JP2021151752A - Inkjet recording device - Google Patents

Abstract

To solve the problem that adhesion strength is improved when fixing by pressurizing is performed before a temperature of a formed film falls down, before cooling is performed just after heating, however the adhesion strength cannot be improved when the pressurization is performed in a state where cooling of the film is in progress.SOLUTION: An inkjet recording device is mounted with: a heating mechanism that can heat first ink containing a color material, second ink containing aqueous resin fine particles and not containing a color material and a recording medium and ink recorded on the recording medium during recording or after recording; and pressurizing means that can pressurize an ink layer formed for a certain period of time after heating is completed, which makes the heating mechanism perform heating processing, after performing recording to the recording medium, using the first ink and the second ink, and performs pressurizing processing in a certain period of time after the heating processing. It is determined by estimating adhesion strength from a fixing condition whether the pressurizing processing is to be performed or not.SELECTED DRAWING: Figure 1

Description

The present invention relates to an inkjet recording apparatus that records an image by ejecting a recording liquid such as ink onto a recording medium while scanning a recording head.

Inkjet recording methods include not only printing on permeable recording media such as paper (hereinafter, also referred to as media), but also printing on non-permeable recording media using plastics such as polyvinyl chloride and polyethylene terephthalate. Applications are being developed. Further, in recent years, water-based inks for non-permeable recording media, which are highly environmentally safe, have been commercialized. On the other hand, the ink fixability may be insufficient for non-penetrating media. This is because in the case of ordinary penetrating media, the ink permeates the inside of the media, so that a strong bonding state is likely to be developed between the ink media, but in the case of non-penetrating media, the ink does not permeate inside. Strong adhesion between ink and media is unlikely to occur.

The prior art document discloses a technique for improving the fixability by applying pressure after recording on such a non-penetrating medium.

Japanese Unexamined Patent Publication No. 2005-271590

However, the inventors have found that in a system such as the above-mentioned prior art document, the effect obtained is significantly different depending on the timing of pressure fixing by a roller after heating. Adhesion strength is improved by fixing by pressurization before cooling is performed immediately after heating and before the temperature of the formed film drops, but adhesion strength is improved even if pressurization is performed while the film is being cooled. It is difficult to obtain the improvement effect of.

Further, as disclosed in the prior art, it is possible to perform heating after cooling, but if such a configuration is adopted, heating → cooling → reheating will be performed, resulting in a wasteful process. In addition, sufficient adhesion strength cannot be obtained.

On the other hand, if the heating time and the elapsed time after heating are too short, sufficient adhesion strength cannot be obtained.

An object of the present invention is to provide an inkjet recording apparatus capable of obtaining sufficient adhesive strength of an ink film even in a non-absorbent medium in which it is relatively difficult to obtain adhesive adhesive strength between ink and media.

In order to solve the above problems, the inkjet recording apparatus of the present invention includes a first ink containing a color material and a second ink containing water-based resin fine particles and does not contain a color material, and a recording medium and recording during or after recording. Equipped with a heating mechanism that can heat the ink recorded on the medium and a pressurizing means that can pressurize the ink layer formed within a certain period of time after the end of heating, the first ink and the first ink are provided for the recording medium. (Ii) After recording with ink, heat treatment is performed by a heating mechanism, and pressure treatment is performed within a certain period after the heat treatment.

Further, in the inkjet recording device having such a configuration, in order to perform more effective fixing, the adhesive strength is estimated from the fixing temperature, the pause between scans, etc., and it is assumed that sufficient adhesive strength cannot be obtained by low temperature fixing or the like. If this is the case, fixing with a pressure roller can be performed, and conversely, if it is estimated that sufficient fixing strength cannot be obtained only from the dried portion, roller fixing can be performed.

The parameters for estimating the adhesive strength can be estimated from (1) fixing temperature, (2) presence / absence of inter-scan weight, (3) media type, (4) amount of reaction solution to be used, and the like.

By using the above means, sufficient adhesive strength of the ink film can be obtained even in a non-absorbent medium in which it is relatively difficult to obtain the adhesive adhesive strength between the ink and the media.

It is a figure explaining the main body structure of 1st Embodiment. It is a figure explaining the main body structure of 1st Embodiment. It is a figure explaining the recording head of 1st Embodiment. It is a figure explaining the control system of 1st Embodiment. It is a figure explaining the setting state of the main body panel of 1st Embodiment. It is a figure which showed the temperature change of the recording medium of 1st Embodiment. The judgment flow of the third embodiment is shown. It shows another judgment flow of the 3rd Embodiment. It is a flowchart of an example of control of a pressurization control mechanism. It is a figure explaining the main body structure of 1st Embodiment. It is a table which shows the relationship between the state of pressurization and heating and the state of fixing. It is a table which shows the correspondence between each media type and control.

(First Embodiment)
The first embodiment of the present invention will be described.

<Main unit configuration>
FIG. 1 is a perspective view showing the configuration of a main part of the inkjet recording device, and FIG. 2 is a side view showing the configuration of the main part of the inkjet recording device. A housing 1 is provided inside the inkjet recording device, and a platen 2 is arranged on the housing 1. Further, a suction device 4 for sucking the sheet-shaped recording medium 3 onto the platen 2 is provided in the housing. Further, a carriage 6 that reciprocates in the main scanning direction is supported by a main rail 5 installed in the longitudinal direction of the housing 1. The carriage 6 is equipped with an inkjet recording head 7, and the recording head 7 can use various inkjet methods such as a method using a heating element and a method using a piezo element.

The carriage motor 8 is a drive source for moving the carriage 6 in the main scanning direction, and the rotational driving force thereof is transmitted to the carriage 6 by the belt 9. The position of the carriage 6 in the main scanning direction is detected and monitored by the linear encoder. The linear encoder includes a linear encoder pattern 10 attached to the housing 1 and a reading unit (not shown) mounted on the carriage 6 that reads the linear encoder pattern 10 optically, magnetically, or mechanically. The recording medium 3 is fed from the roll-shaped paper feed medium 23 provided on the paper feed spool 18. The paper feed spool 18 includes a torque limiter 19 for applying a braking force to the recording medium 3. The recording medium 3 is conveyed on the platen 2 in the sub-scanning direction (in the direction of the arrow in the drawing) orthogonal to the main scanning direction of the carriage 6.

This transfer is performed by a drive mechanism including a transfer roller 11, a pinch roller 16, a belt 12, and a transfer motor 13. The drive state (rotation amount, rotation speed) of the transfer roller 11 is detected and monitored by the rotary encoder. The rotary encoder includes a circumferential encoder pattern 14 that rotates together with the transport roller 11 and a reading unit 15 that optically, magnetically, or mechanically reads the encoder pattern 14. After being recorded by the recording head 7, the recording medium 3 is wound by the take-up spool 20 to form a roll-shaped take-up medium 24. The take-up spool 20 is rotated by a take-up motor 21 and includes a torque limiter 19 for applying a take-up tension to the recording medium 3.

The liquid ink is fixed to the recording medium by the heat from the heater 25, which is located at a position facing the platen 2 and is supported by a frame (not shown).

The heater 25 is covered with a heater cover 26, and the heater cover 26 has a function of efficiently irradiating the paper surface with the heat of each heater and a function of protecting the heater. The ink as an example of the liquid discharged from the discharge head 7 is fixed by the heat from the heater 25 and the heat from the heated recording medium 3 after landing on the recording surface.

<Head configuration>
FIG. 3 is a plan view schematically showing an arrangement of discharge ports of a recording head (shown in FIG. 1-7) used in the embodiment of the present invention. The recording head shown here is provided with a plurality of nozzles for ejecting ink. This nozzle consists of an ejection port n for ejecting ink and an ink flow path (not shown) communicating with the ejection port n. Ink is locally heated in the ink flow path of each nozzle to cause film boiling. An electrothermal converter that ejects ink with the foaming energy is provided. The recording head is arranged with a row of ejection ports corresponding to each of the inks of a plurality of colors to be used. Each discharge port row of the present embodiment is composed of 1280 discharge ports arranged at a density of 1200 dpi along the sub-scanning direction which is the transport direction of the recording medium.

The recording head in the present embodiment ejects black (Bk), cyan (C), magenta (M), yellow (Y) inks, and water-based resin fine particle inks in order to enable recording of a full-color image. Is a so-called side-by-side head in which the heads are sequentially arranged along the X direction. When the reaction solution or the like required in the second embodiment is used, a row of discharge ports is added side by side.

In the inkjet recording apparatus configured in this way, the recording medium is conveyed from a transfer unit (not shown) in the sub-scanning direction. The recording head receives a recording signal from a recording control unit (not shown), moves in the main scanning direction together with the carriage 6, and ejects ink toward the recording area of the recording medium. Recording is performed by repeating such a recording operation and a transport operation of transporting a recording medium by a predetermined amount in the sub-scanning direction. That is, the image is recorded by scanning the recording head.

<Ink composition>
Next, the ink used in this embodiment will be described. Hereinafter, the terms "part" and "%" are based on mass unless otherwise specified.

The color ink containing the pigment used in the present embodiment and the clear ink containing no pigment or containing only a small amount of the pigment contain a water-soluble organic solvent. The water-soluble organic solvent preferably has a boiling point of 150 ° C. or higher and 300 ° C. or lower for the reason of wettability and moisturizing property of the head face surface. Further, from the viewpoint of the function of the film-forming auxiliary for the resin fine particles and the swelling solubility in the recording medium on which the resin layer is formed, a ketone compound such as acetone or cyclohexanone, a propylene glycol derivative such as tetraethylene glycol dimethyl ether, N. A heterocyclic compound having a lactam structure typified by −methyl-pyrrolidone and 2-pyrrolidone is particularly preferable. From the viewpoint of discharge performance, the content of the water-soluble organic solvent is preferably 3 wt% or more and 30 wt% or less.

Specifically, the water-soluble organic solvent has 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol. Alcohols. Amides such as dimethylformamide and dimethylacetamide. Ketone or keto alcohols such as acetone and diacetone alcohol. Ethers such as tetrahydrofuran and dioxane. Polyalkylene glycols such as polyethylene glycol and polypropylene glycol. ethylene glycol. Alternatively, alkylene glycols containing 2 to 6 carbon atoms such as propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol. Lower alkyl ether acetate such as polyethylene glycol monomethyl ether acetate. Glycerin. Lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether. Polyhydric alcohols such as trimethylolpropane and trimethylolethane, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned.

The water-soluble organic solvent as described above can be used alone or as a mixture. Further, it is desirable to use deionized water as the water. The content of the water-soluble organic solvent contained in the reaction solution used in the present invention is not particularly limited. However, the color ink and clear ink used in the present invention have, in addition to the above-mentioned components, surfactants, antifoaming agents, preservatives, fungicides, etc., in order to have desired physical property values as needed. Can be added as appropriate.

In view of the above points, in the present embodiment, a method for producing magenta ink as the color ink and water-based resin fine particle ink as the clear ink will be described.

(Color ink)
(Magenta ink)
(1) Preparation of dispersion First, using benzyl acrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 300 and a number average molecular weight of 2500 was prepared by a conventional method, and further neutralized with an aqueous potassium hydroxide solution. A homogeneous 50% by mass polymer aqueous solution was prepared by diluting with ion-exchanged water.

100 g of the above polymer solution, C.I. I. Pigment Red 122 and 300 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hours.

The mixture was then treated using a microfluidizer by passing the mixture through the interaction chamber 5 times under a liquid pressure of about 70 MPa.

Further, the dispersion obtained above was centrifuged (12,000 rpm, 20 minutes) to remove non-dispersions containing coarse particles to obtain a magenta dispersion. The obtained magenta dispersion had a pigment concentration of 10% by mass and a dispersant concentration of 5% by mass.

(2) Preparation of Ink For the preparation of ink, the above magenta dispersion liquid is used, and the following components are added thereto to obtain a predetermined concentration. Then, after sufficiently mixing and stirring these components, pressure filtration is performed with a microfilter (manufactured by Fujifilm Co., Ltd.) having a pore size of 2.5 μm to obtain a pigment ink having a pigment concentration of 4% by mass and a dispersant concentration of 2% by mass. Prepared.

40 parts of the above magenta dispersion,
2-Pyrrolidone 5 copies,
15 parts of 2-methyl1,3 propanediol,
0.5 parts of acetylene glycol EO adduct,
FS-3100 0.5 copies,
(Manufactured by Kawaken Fine Chemical Co., Ltd.) Ion-exchanged water balance.

(Aqueous resin fine particle ink)
(Resin fine particles)
In the present invention, the "resin fine particles" mean fine particles made of resin and having a particle size that can be dispersed in an aqueous medium. The resin fine particles have a function of fixing the pigment on the surface of the recording medium by melting by heating and forming a film (film formation) on the surface of the recording medium.

The glass transition point Tg of the resin constituting the resin fine particles is more than 30 ° C and less than 80 ° C. When the temperature is 30 ° C. or lower, the difference between the Tg of the resin and the room temperature is small, and the resin fine particles are in a state close to the molten state even in the ink, so that the viscosity of the ink increases and the color development of the image decreases due to poor ink ejection. In some cases. When the temperature is 80 ° C. or higher, a large amount of heat is required to melt the resin fine particles, and the resin fine particles cannot be melted before the pigment agglomerates due to the evaporation of water in the ink. Color development may decrease. The Tg of the resin is preferably 31 ° C. or higher and 79 ° C. or lower, and more preferably 40 ° C. or higher and 60 ° C. or lower.

The resin constituting the resin fine particles is not particularly limited as long as the glass transition point Tg satisfies the above range. Specifically, acrylic resin fine particles synthesized by emulsion polymerization of a monomer such as (meth) acrylic acid alkyl ester or (meth) acrylic acid alkylamide; (meth) acrylic acid alkyl ester or (meth) acrylic acid alkyl acid. Examples thereof include styrene-acrylic resin fine particles synthesized by emulsion polymerization of amide and the like and a styrene monomer; polyethylene resin fine particles, polypropylene resin fine particles, polyurethane resin fine particles, styrene-butadiene resin fine particles, and the like. In addition, core-shell type resin fine particles having different polymer compositions between the core portion and the shell portion constituting the resin fine particles and acrylic fine particles synthesized in advance to control the particle size are used as seed particles and emulsion polymerization is carried out around the seed particles. The obtained resin fine particles may be used. Further, hybrid type resin fine particles in which different resin fine particles such as acrylic resin fine particles and urethane resin fine particles are chemically bonded may be used.

Further, "polymer fine particles existing in a state of being dispersed in water" is a form of resin fine particles obtained by homopolymerizing a monomer having a dissociative group or copolymerizing a plurality of types, so-called self-dispersing resin fine particle dispersion. It may be a body. Here, examples of the dissociable group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group, and examples of the monomer having this dissociative group include acrylic acid and methacrylic acid. Further, a so-called emulsified dispersion type resin fine particle dispersion in which resin fine particles are dispersed by an emulsifier may be used. As the emulsifier, a material having an anionic charge can be used regardless of the low molecular weight or the high molecular weight.

In the present invention, the resin fine particles having a sulfonic acid group are insoluble in water and can be used as resin fine particles composed of any commonly used resin component.

The resin component constituting the resin fine particles is not particularly limited as long as it is a resin containing a sulfonic acid group, and any commonly used natural or synthetic polymer, a polymer newly developed for the present invention, or the like can be used. Any resin component can be used without limitation. In particular, from the viewpoint of being generally usable and facilitating the functional design of resin fine particles, a polymer or co-weight of a monomer component having a radically polymerizable unsaturated bond, such as an acrylic resin or a styrene / acrylic resin. You can use coalescence.

Examples of the hydrophilic radically polymerizable unsaturated monomer (hereinafter referred to as a monomer) having a sulfonic acid group used in the present invention include styrene sulfonic acid, -2-propyl acrylamide sulfonic acid, and ethyl -2-sulfonic acid acrylate. , Ethyl methacrylate-2-sulfonic acid, butyl acrylamide sulfonic acid and salts thereof and the like.

Further, as the hydrophilic monomer, in addition to the above-mentioned monomer having a sulfonic acid group, carboxyl such as acrylic acid, methacrylic acid, crotonic acid, etaacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, fumaric acid and the like. A monomer having a group and a salt thereof, a monomer having a phosphonic acid group such as ethyl methacrylate-2-phosphonate, ethyl -2-phosphonate acrylate and the like may be used together.

Examples of the monomers classified as hydrophobic monomers include methyl acrylate, ethyl acrylate, isopropyl acrylate, -n-propyl acrylate, -n-butyl acrylate, -t-butyl acrylate, and acrylic acid. Benzyl, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, -n-propyl methacrylate, -n-butyl methacrylate, isobutyl methacrylate, -t-butyl methacrylate, tridecyl methacrylate, benzyl methacrylate, etc. ( Meta) Acrylic acid ester; styrene-based monomers such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-tert-butylstyrene, etc .; Itaconic acid ester such as benzyl itaconate, etc. Acrylic acid esters such as dimethyl maleate; fumaric acid esters such as dimethyl fumarate; acrylic acid nitriles, methacrylonitrile, vinyl acetate and the like. In addition, various known or new oligomers, macromonomers and the like can be used without limitation.

Since the radically polymerizable monomer used in the production method according to the present invention is a component constituting resin fine particles having a sulfonic acid group through aqueous precipitation polymerization, it may be appropriately selected depending on the characteristics of the resin fine particles to be obtained. In the production method of the present invention, any conventionally known radically polymerizable monomer or a radically polymerizable monomer newly developed for the present invention can be used.

In the present invention, in particular, the resin fine particles having a sulfonic acid group are composed of a copolymer of a monomer component containing a hydrophilic monomer having at least one kind of sulfonic acid and at least one kind of hydrophobic monomer among the above-mentioned fine particles. The configuration is preferable in that an aqueous inkjet recording ink having dispersion stability and suitable print recording characteristics can be obtained. That is, when producing the resin fine particles, various control factors such as the type and concentration of the polymerization initiator used, the type of the constituent monomers, the copolymerization ratio, and the like, various kinds of the resin fine particles adhering to the surface of the coloring material are used. It is possible to appropriately control the characteristics and the like.

The radical polymerization reaction conditions vary depending on the properties of the polymerization initiator, dispersant, and monomer used, but for example, the reaction temperature is 100 ° C. or lower, preferably 40 ° C. or higher and 80 ° C. or lower. The reaction time is 1 hour or more, preferably 6 hours or more and 30 hours or less. The stirring speed during the reaction is preferably 50 rpm or more and 500 rpm or less, preferably 150 rpm or more and 400 rpm or less.

In the above-mentioned steps, particularly when at least one kind of hydrophobic monomer and a hydrophilic monomer containing at least a sulfonic acid group are polymerized to obtain resin fine particles having a sulfonic acid group, the monomer component is preferably aqueous. It is desirable to drop it into an aqueous dispersion containing a radical polymerization initiator. In order to uniformly obtain resin fine particles having a desired sulfonic acid group from a mixture of monomers having different properties such as a hydrophobic monomer and a hydrophilic monomer, the copolymerization ratio of the monomers having different properties should always be kept constant. Is desirable. When the mixture of the monomers is added into the polymerization system in excess of the amount of the monomers consumed in the polymerization reaction within a certain period of time, only a specific monomer species is polymerized in advance, and the remaining monomers are polymerized in advance. There is a tendency to polymerize after the resulting monomer is consumed, and in this case, a large non-uniformity occurs in the properties of the resin fine particles having a sulfonic acid group to be produced.

A resin component having a large content of a hydrophilic monomer component may not be precipitated due to its high hydrophilicity, and resin fine particles having a sulfonic acid group may not be formed and may remain in the system as a water-soluble resin component. be. The above-mentioned method for synthesizing the resin fine particles can be carried out by a known general method for synthesizing the resin fine particles.

In the present invention, first, insoluble resin fine particles are dispersed in a water-soluble resin that functions as a dispersant to obtain an aqueous dispersion. The resin fine particles obtained by this step are resin fine particles having a sulfonic acid group, and are excellent in dispersion stability by themselves. Hereinafter, preferred embodiments of the above manufacturing method will be described in detail.

In the present embodiment, a specific method for dispersing the resin fine particles will be described.

First, in a nitrogen atmosphere and heated to 70 ° C., the following three additive liquids were gradually added dropwise while stirring with a motor, and polymerization was carried out for 5 hours. Each additive solution is a mixed solution containing a hydrophobic monomer consisting of 28.5 parts of methyl methacrylate, a hydrophilic monomer consisting of 4.3 parts of sodium p-styrene sulfonate and 30 parts of water, and 0.05 part of potassium persulfate. It is a mixed solution containing 30 parts of water and a polymerization initiator.

The following components are mixed so that the obtained resin fine particles are 10% in the ink, and further pressure-filtered with a microfilter (manufactured by FUJIFILM Corporation) having a pore size of 2.5 μm to obtain an aqueous resin fine particle ink. And said.

2-Pyrrolidone 5 copies,
15 parts of 2-methyl1,3 propanediol,
0.5 parts of acetylene glycol EO adduct,
FS-3100 0.5 copies,
(Manufactured by Kawaken Fine Chemical Co., Ltd.) Ion-exchanged water balance.

Surfactants are used for the purpose of improving wettability to impermeable recording media. The larger the amount of the surfactant added, the stronger the property of lowering the surface tension of the ink, and the better the wettability and permeability of the ink to the recording medium. Surfactant It is preferable to use an acetylene glycol EO adduct or a fluorine-based or silicone-based surfactant. Since the surface tension of the ink can be reduced even with a small amount of the fluorine-based or silicone-based surfactant, the wettability of the ink to the recording medium can be improved. As a result, even when recording is performed on a non-penetrating recording medium, the phenomenon that the ink is repelled on the surface of the recording medium is suppressed, and the image quality can be further improved.

As the fluorine-based or silicone-based surfactants, all of the following are trade names, for example, Zonyl FSO, Zonyl FSO100, Zonyl FSN, Zonyl FSN100, Capstone FS-3100 (all manufactured by DuPont); Megafvck F-410. , Mega Fvck F-493, Mega Fvck F-443, Mega Fvck F-444, Mega Fvck F-445 (all made by DIC); Novec FC-4430, Nov
ec FC-4432 (above, made by 3M); Futergent 100, Futergent 150
, Futagent 150CH, Futagent 250, Futagent 400SW, Futagent 501 (above, made by Neos); KS508, KP360A, KP360A (above, made by Shinetsu Silicone); FZ-2191, FZ-2123, 8211ADDITIVE (
As mentioned above, manufactured by Toray Dow Corning); etc.

In the case of this example, a surfactant was added to adjust the surface tension to 30 dyn / cm or less as a preferable surface tension. A fully automatic tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) was used to measure the surface tension. The measuring instrument is not limited to the above-exemplified one as long as the surface tension of the ink can be measured.

Further, since all the inks of the present embodiment use an anionic coloring material, the pH of the ink is stable on the alkaline side, and the value is 8.5 to 9.5. In general, the pH of the ink is 7.0 or more 10. It is preferably 0 or less. For the measurement of pH, pHMETER model F-52 manufactured by HORIBA, Ltd. was used. The measuring instrument is not limited to the above-exemplified one as long as it can measure the pH of the ink.

<Heating mechanism>
In the recording method of the present invention, the resin fine particles on the impermeable recording medium to which the ink is applied are heated to melt the resin fine particles, and the solvent in the ink is evaporated to make the pigment into the recording medium. Can be fixed. Therefore, it is desirable that the heating temperature is equal to or higher than the minimum film forming temperature of the resin fine particles. In addition, since it is necessary to evaporate most of the liquid components such as the solvent in the ink during heating, the recording medium transport direction is sufficient to secure a heating time for supplying the energy required for evaporating most of the liquid components. It has a structure with a temperature distribution of.

The "minimum film forming temperature MFT" as used in the present invention means the minimum temperature required for the resin fine particles to be melted by heating to form a resin film (film formation). MFT can be easily measured using a minimum film-forming temperature measuring device. In this minimum film-forming temperature measuring device, an ink containing resin fine particles (including pigment, water, a water-soluble solvent, and resin fine particles at least) is spread on a metal plate having a high thermal conductivity with a temperature gradient and dried. The temperature at the point where the film is formed is measured as the minimum film formation temperature. In the present invention, unless otherwise specified, MFT means the minimum film-forming temperature of resin fine particles in the form of ink, and the minimum film-forming temperature in an aqueous dispersion that does not contain a coloring material such as a pigment or a water-soluble solvent. It doesn't mean anything.

Further, the recording method of the present invention includes at least a step of heating the surface of the impermeable recording medium to which the ink is applied, and sub-scanning from the vicinity of the region to which the ink is applied in the impermeable recording medium. It has a step of heating a portion on the downstream side in the direction.

Specifically, the heating mechanism is such that a nickel alloy heater is placed below the aluminum alloy platen manufactured by the die cast method, which is not easily deformed by heat, the platen is heated by the heater, and the platen is used for heating. The method of doing this can be mentioned. Further, a method of heating the surface of the recording medium by using a sheathed heater, a halogen heater and a heat reflector can be mentioned.

In the present embodiment, the heating temperature is preferably 50 ° C. to 120 ° C. If the temperature is lower than 50 ° C, a large amount of solvent contained in the ink may remain in the ink film, and if the heating temperature is 120 ° C or higher, the recording medium may be deformed. be.

<Control system configuration>
FIG. 4 is a block diagram showing a schematic configuration of the control system according to the present embodiment. The main control unit 1 includes a CPU 2 that executes processing operations such as calculation, selection, discrimination, and control, a ROM 3 that stores a control program or the like to be executed by the CPU 2, a RAM 4 that is used as a buffer for recorded data, and input / output. It has a port 5 and the like. The input / output ports 5 are connected to drive circuits 6, 7, 8 and 9 such as a transfer motor (LF motor) 10, a carriage motor (CR motor) 11, a recording head 12 and an actuator in the heating mechanism 13. There is. Further, an operation panel 15 is connected to the input / output port 5 so that the control program can be operated. Further, the main control unit 1 is connected to the host PC 16 via the interface circuit 14. The printer is controlled by software installed on the host PC 16.

<Fixing process>
The fixing process of this embodiment will be described with reference to FIGS. 1 and 2.

As described in the main body configuration, the heater 25 is provided at a position facing the platen 2, and the heat from the heater promotes the evaporation of the water solvent or the like of the liquid ink to fix it on the recording medium.

The heater 25 is covered with a heater cover 26, and the heater cover 26 has a function of efficiently irradiating the paper surface with the heat of each heater and a function of protecting the heater. The ink as an example of the liquid discharged from the discharge head 7 is fixed by the heat from the heater 25 and the heat from the heated recording medium 3 after landing on the print recording surface. The recording medium 3 is held at a position facing the heater 25 with the medium in between, and infrared rays or the like emitted from the heater 25 and transmitted through the recording medium 3 are prevented from being emitted to the outside, and infrared rays are absorbed or reflected. This plays a role in improving the heating efficiency.

The pressurizing roller 27 is provided directly below the heater 25 in the traveling direction of the recording medium. It is desirable that the nip rollers 28 are provided at positions facing each other across the media so that an appropriate pressure can be applied to the resin film formed on the recording medium 3. Further, in the case of this embodiment, the pressure applied to the pressurizing roller 27 is increased by the solenoid 30 to prevent the media from being damaged or the nip roller 28 from being damaged. A pressure spring 29 for adjustment is provided between the pressure spring 29 and the solenoid 30.

The optimum timing of pressurization differs depending on the media type, the resin in the ink, the composition of the ink solvent, and the like, but in another embodiment of this embodiment, the pressurization treatment is performed before the temperature drops.

That is, by providing a pressurizing roller in the area of the heating heater 26 as shown in FIG. 10 and performing pressurization in a state where the temperature is sufficiently high, it is possible to effectively exert the pressurizing effect. ..

The results of the test conducted in such a configuration are shown in FIG.

(Second Embodiment)
This embodiment shows an example in which a reaction solution is used in addition to the color ink and the water-based resin fine particle ink.

This embodiment basically has the same configuration as that of the first embodiment, but uses a reaction solution as the ink. The reaction solution is for suppressing the movement of the pigment in the liquid on the recording medium by aggregating or insolubilizing the pigment. As a result, it is possible to prevent the adverse image quality caused by visually recognizing the density unevenness caused by the movement of the pigment, which is particularly remarkable in the non-penetrating recording medium, and it is possible to obtain a suitable image in the non-penetrating recording medium. .. The details of the ink composition of the reaction solution and the recording control are described below.

When a reaction solution is used as in this example, it is common that the reaction solution and the aqueous resin are reactive. In such a case, the water-soluble resin may aggregate before the heat film formation due to the action of the reaction solution, so that sufficient adhesion strength may not be obtained.

The present invention is considered to work more effectively in cases such as those of the present embodiment.

<Ink composition>
(Reaction solution)
The reaction solution used in the present invention contains a reactive component that reacts with the pigment contained in the ink to aggregate or insolubilize the pigment. Specifically, the above-mentioned reactive component is dispersed when it is mixed with an ink having a pigment that is stably dispersed or dissolved in an aqueous medium by the action of an ionic group on a recording medium or the like. A component that can destroy stability. More specifically, it is at least one selected from organic acids, metal salts (particularly polyvalent metal ions and salts thereof) and cationic polymers. Hereinafter, each of these reactive components will be described.

<Reactive component>
(Organic acid)
In the present invention, the organic acid used as the reactive component of the reaction solution is preferably one that is soluble in water. Specific examples of organic acids include oxalic acid, polyacrylic acid, formic acid, acetic acid, propionic acid, glycolic acid, malonic acid, malonic acid, maleic acid, ascorbic acid, levulinic acid, succinic acid, glutaric acid, glutamic acid, and fumaric acid. , Citric acid, tartaric acid, lactic acid, pyrrolidone carboxylic acid, pyron carboxylic acid, pyrrol carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumarin acid, thiophene carboxylic acid, nicotinic acid, oxysuccinic acid, dioxysuccinic acid and the like. The content of the organic acid is preferably 3.0% by mass or more and 90.0% by mass or less, and preferably 5.0% by mass or more and 70.0% by mass or less, based on the total mass of the liquid composition. More preferred.

(Multivalent metal salt)
Specific preferred polyvalent metal ions that can be used as the reactive component of the reaction solution constituting the present invention include, for example, Ca2 +, Cu2 +, Ni2 +, Mg2 +, Zn2 +, Sr2 + and Ba2. Examples include divalent metal ions such as +. Further, trivalent metal ions such as Al3 +, Fe3 +, Cr3 + and Y3 + can be mentioned, but the present invention is not limited thereto. In order to contain these polyvalent metal ions in the reaction solution, it is preferable to use a salt of the polyvalent metal. The salt is a metal salt composed of polyvalent metal ions as described above and anions bonded to these ions, but it is required to be soluble in water. Preferred anions for forming salts include, but are limited to, for example, Cl-, NO3-, I-, Br-, ClO3-, SO42-, CO32-, CH3COO- and HCOO-. It's not something.

In the present invention, Ca2 +, Mg2 +, Sr2 +, Al3 + and Y3 + are particularly preferable as the polyvalent metal ion from the viewpoints of reactivity, colorability, ease of handling and the like, and among them, Ca2 + Is particularly preferred. Further, as an anion for forming a salt with a polyvalent metal ion, methanesulfonic acid is particularly preferable from the viewpoint of safety and the like. Therefore, the metal salt used in the present invention was calcium methanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.). Hereinafter, the reactivity with the resin fine particles and the pigment particles when a polyvalent metal salt is used as the reactive component will be described. The polyvalent metal salt destroys the hydration structure of the dispersed particles by increasing the salt concentration, and promotes aggregation of the particles. In other words, it can be expected that dispersion fracture will proceed uniformly for particles that take a dispersion form other than particles that are dispersed only by steric hindrance. In the present embodiment, a reaction solution 2 containing calcium methanesulfonate as a reactive component was prepared. The reaction solution 2 was used as Comparative Example 1 in which the dispersed forms of both the resin fine particles and the pigment particles were destroyed. Further, the reaction solution containing the above-mentioned metal salt as a reactive component preferably does not contain a pigment and is colorless, but it does not necessarily have to show absorption in the visible region. That is, even if absorption is shown in the visible region, absorption may be shown in the visible region as long as it does not substantially affect the image.

(Cationic polymer)
In the present invention, the cationic polymer used as the reactive component of the reaction solution is preferably one that is soluble in water. Specific examples of the cationic polymer include polyallylamine hydrochloride, polyaminesulfonate, polyvinylamine hydrochloride, chitosan acetate and the like. In addition to this, a copolymer of vinylpyrrolidone obtained by cationizing a part of a nonionic polymer substance and an aminoalkylal chelate quaternary salt, a copolymer of acrylic amide and an aminomethylacrylic amide quaternary salt, etc. Can be mentioned. Of course, it goes without saying that the present invention is not limited to these compounds.

In the present invention, polyallylamine hydrochloride (PAA-HCL-03 / manufactured by Nittobo Medical Co., Ltd.) was used as a representative example of the cationic polymer. Hereinafter, the reactivity with the resin fine particles and the pigment particles when a cationic polymer is used as the reactive component will be described. The cationic polymer can be considered in two ways, one is the case where the hydration structure of the resin fine particles and the pigment particles is destroyed, and the other is the case where the cationic polymer is self-precipitated. That is, when the cationic polymer is stronger as an acid, the hydrated structure of the cationic polymer is not destroyed (maintains the ionic state), but the hydrated structure on the particle side is destroyed. On the other hand, when the cationic polymer is weaker as an acid, the hydration structure of the cationic polymer is destroyed and itself is precipitated. That is, it can be expected that when the acid on the particle side is weak, the particle side is aggregated, and when the acid on the particle side is strong, the dispersed particles are aggregated by precipitating themselves. In the present embodiment, a reaction solution 3 in which the reactive component was polyallylamine hydrochloride was prepared. The reaction solution 3 was used as Comparative Example 2 in which the dispersed forms of both the resin fine particles and the pigment particles were destroyed.

Further, the reaction solution containing a cationic polymer as a reactive component is preferably colorless, but does not necessarily have to show absorption in the visible region. That is, even if it shows absorption in the visible region, it may be a light-colored one that shows absorption in the visible region as long as it does not affect the image when the image is formed. ..

<Preparation of reaction solution>
Three types of reaction solutions were prepared according to the types of the above-mentioned reactive components.

(Reaction solution 1)
Glutaric acid 3 parts,
2-Pyrrolidone 5 copies,
15 parts of 2-methyl1,3 propanediol,
0.5 parts of acetylene glycol EO adduct,
FS-3100 0.5 copies,
(Manufactured by Kawaken Fine Chemical Co., Ltd.) Ion-exchanged water balance.

(Reaction solution 2)
Calcium methanesulfonate 5 parts,
2-Pyrrolidone 5 copies,
15 parts of 2-methyl1,3 propanediol,
0.5 parts of acetylene glycol EO adduct,
FS-3100 0.5 copies,
(Manufactured by Kawaken Fine Chemical Co., Ltd.) Ion-exchanged water balance.

(Reaction solution 3)
Polyallylamine hydrochloride 1.5 parts,
2-Pyrrolidone 5 copies,
15 parts of 2-methyl1,3 propanediol,
0.5 parts of acetylene glycol EO adduct,
FS-3100 0.5 copies,
(Manufactured by Kawaken Fine Chemical Co., Ltd.) Ion-exchanged water balance.

<Pressure treatment>
The pressurizing mechanism used in this embodiment has the same configuration as that of the first embodiment. However, a pressurization control mechanism is provided to control the execution / non-execution of pressurization after heating depending on the use / non-use of the reaction solution or the recorded concentration of each of the reaction solution / ink. An example of control is shown in FIG.

(Third Embodiment)
<Heating control>
In this embodiment, as shown in FIG. 7, it is controlled whether or not pressurization is performed based on the heating temperature.

It is generally desirable that the heater temperature be as low as possible because it causes less media damage and consumes less energy. On the other hand, there is a certain degree of correlation between the heating temperature / time / solvent evaporation amount, the film strength, and the bond strength of the film to the media, and it is desirable for the resin film to have the solvent almost completely evaporated. As for the evaporation of water, solvent, etc., the higher the heating temperature, the faster the evaporation, so at present, a relatively high temperature of 100 ° C. or higher is used.

In this embodiment, as shown in FIG. 7, it is configured to determine whether or not pressurization is performed according to the fixing temperature set before the recording operation. The predetermined temperature is set in the storage device ROM 3 of the main body in advance, and the fixing temperature set by the user or selected by the main body is read from the RAM 4. If the set temperature is equal to or less than the predetermined value according to the judgment result, the solenoid 30 is operated. The pressurizing roller 27 is brought into contact with the media to control the pressurization. If it is more than a predetermined value, the recording operation is performed as it is without using the pressurization by the pressurizing roller 27.

The temperature state of the media when this example is used is shown in FIG. In normal operation, the temperature rises to the fixing temperature as shown by the dotted line, and then drops sharply due to the cooling fan. On the other hand, in order to perform fixing by pressurization, cooling at the outlet is not performed as shown by the solid line in the figure. As a result, the temperature of the ink film on the media is maintained at a high temperature for a while even after passing through the heater 27. (Region indicated by arrow A in the figure) If pressure fixing is performed in the zone A where the temperature is maintained after this configuration, pressure fixing can be performed efficiently.

Further, as a similar configuration, FIG. 8 shows an example in which it is determined whether or not pressure fixing is performed depending on the presence or absence of a weight between scans. In FIG. 8, when a pause of a predetermined value or more (3s is set in this example) is set by the user or the main body (NO is selected in S8), no pressurization is performed and the set value is equal to or less than the predetermined value. In the case (when YES is selected in S8), pressure fixing is performed. This is because the adhesion strength of the resin film can be sufficiently obtained by setting the pause time to a predetermined time or longer, and when the weight between scans is performed, the media that has passed through the heater 25 reaches the fixing roller 27. This is because the temperature drops during that time, and the effect of pressure fixing cannot be sufficiently obtained.

(Fourth Embodiment)
<Media control>
In this embodiment, the configuration in the case of controlling whether or not pressurization is performed depending on the media type is shown. The media type is selected from the menu of driver, RIP, etc. as shown in FIG. Each medium is usually associated with a so-called recording mode suitable for each medium, and this recording mode includes the number of recording passes, the maximum recording density, a thinning mask, and the like. Similarly, in a recording device such as that used in this embodiment, information about heating / drying after performing a recording operation is associated with the media type. These drying conditions include conditions necessary for fixing, such as heating temperature, ventilation conditions, and waiting time for each scan.

In the case of this embodiment, in addition to the above drying conditions, the presence or absence of pressurization treatment is held as information linked to the media type, and when the media to be recorded is selected at the start of recording, pressurization in the library is performed. It is configured to call up information on the presence or absence of processing. Although the information regarding pressurization is stored in the host PC 16 in the case of this embodiment, the information stored in the ROM 3 on the printer side may be used.

Further, for example, as shown in FIG. 12, when the heating temperature is defined by the media and there is a correlation between the heating temperature of the media and the pressurizing treatment, the pressurizing treatment is performed when the heating temperature is 60 ° C. or lower. It is also possible to uniformly determine the presence or absence of pressurization treatment according to conditions such as heating temperature and ventilation conditions.

1 Housing 2 Platen 3 Recording medium 4 Suction device 5 Main rail 6 Carriage 7 Recording head 8 Carriage motor 18 Paper feed spool

Claims (9)

A heating mechanism capable of heating the first ink containing a coloring material, the second ink containing an aqueous emulsion resin and not containing a coloring material, and the ink recorded on the recording medium and the recording medium during or after recording. When recording is performed by mounting and heat-treating with the heating mechanism using the first ink and the second ink, the ink film on the heated media is added to the ink film in a state where the temperature is above a predetermined temperature. An inkjet recording device characterized by starting a pressure process. A third ink containing a reactive component that reacts with a coloring material contained in the first ink to aggregate or insolubilize the first ink is provided, and when recording on a non-permeable recording medium, the first ink and the second ink are used. The inkjet recording apparatus according to claim 1, wherein recording is performed using ink and a third ink. The inkjet recording apparatus according to claim 1, wherein the predetermined temperature is Tg or more of the resin component forming the ink film. The inkjet recording apparatus according to claim 1, wherein the pressurizing step is started from a predetermined temperature or higher and is performed until the ink film on the medium becomes a predetermined temperature or lower. The inkjet recording apparatus according to claim 1, wherein the presence or absence of a pressurization step is determined by the so-called number of passes until the image of the recording operation is completed. The inkjet recording apparatus according to claim 1, wherein the presence or absence of pressure fixing is determined by the concentration of the reaction solution with respect to the ink. The inkjet recording apparatus according to claim 1, wherein the presence or absence of performing the pressurizing process is switched depending on the type of media. The inkjet recording apparatus according to claim 1, wherein the presence or absence of the pressurization step is switched depending on the fixing temperature. The inkjet recording apparatus according to claim 1, wherein a roller for pressure fixing is present in a portion heated by a heater.

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