JPH02305870A - Image recording ink - Google Patents

Abstract

PURPOSE:To obtain the title ink without occurrence of toxic gas and adhesion of colored deposit on paper by incorporating a specified electrolyte in a liq. dispersion medium in an ink consisting of a fine powder and a liq. dispersion medium used for performing image recording by changing adhesive properties by applying voltage. CONSTITUTION:In the title ink which consists of a fine powder (e.g. lithium teniolite) and a liq. dispersion medium and with which image recording is performed based on changes in adhesive properties caused by applying voltage by means of a pair of electrodes and adhesion of the ink on one of the electrode, one or more compd. selected from electrolytes producing no halogen ion when dissociated, pref. LiBF4, NaPF6, NH4PF6 or CH3COONa is incorporated in the liq. dispersion medium contg. pref. a polyhydric alcohol solvent (e.g. glycerine).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image recording ink suitably used in a novel image forming method.

[Conventional technology]

Hitherto, common printing techniques such as lithographic printing, letterpress printing, and gravure printing have been known.On the other hand, printers using various recording methods, such as laser printers, are used as recording peripherals for computers and other devices. Beam printers, inkjet printers, thermal transfer printers, wire dot printers and daisy-foil printers are well known.

[Invention or problem to be solved]

Lithographic printing, letterpress printing, gravure printing, and other methods require complicated processes to create the plates, making the plates too expensive, and the difference between the ink in the image area and the non-1jjii image area on the plate. Because dampening water is required for buttering, and complex operations are required to control the activation of ink on the resin on the plate surface, it is difficult to apply conventional printing technology to recording peripherals such as computers. has many difficult aspects.

On the other hand, recording peripheral devices such as computers, etc. include laser beam printers, inkjet printers, thermal transfer printers, wire dot printers, and tigi-foil printers.
The method using a printer has a problem in that it is not suitable for the large-volume printing achieved by the above-mentioned printing technology in terms of cost and the like.

Although inkjet ink jets have low consumable costs, they eject low-viscosity liquid ink from thin nozzles, so the ink tends to solidify and clog when not in use. Furthermore, since the ink used in ink jetting has a low viscosity, it is likely to bleed or blur the image after the ink is transferred to the paper.

The present invention has been made in view of the problems of the prior art described above, and it is an object of the present invention to provide a new image recording ink that can efficiently perform high quality recording in a simple process.

[Failure to solve the problem]

The present invention is an image recording ink consisting of fine particles and a liquid dispersion medium whose adhesion changes when a voltage is applied through a pair of electrodes and adheres to one of the electrodes, and when ionized in the liquid dispersion medium, generates halogen ions. This is an image recording ink characterized by containing no electrolyte.

In other words, this ink is a voltage adhesion control ink that adheres only to either the negative or negative electrode when a voltage is applied, and it is possible to apply a voltage by bringing the patterned electrode into contact with the ink. As a result, it is possible to easily form an ink image on the electrode, and as a result, the cost of the device is low, and only the ink adhering to the electrode is used for image formation, eliminating waste and reducing running costs.

Further, the ink is in the form of a sol with high viscosity, and high quality recording on plain paper is possible.

The voltage adhesion control properties of the ink are improved by the presence of an electrolyte in the liquid dispersion medium, making it possible to smoothly carry out the image recording process described below. In other words, although the ink exhibits ionic conductivity, the presence of a predetermined amount of electrolyte in the liquid dispersion medium allows the electrode reaction to occur efficiently due to the application of voltage, thereby promoting the adhesion control mechanism described below. can be promoted. Generally, the electrolyte is one that generates halogen ions, but because halogen ions have a relatively small overvoltage, they tend to gasify or precipitate on the anode side. Halogen gas is generally toxic, and halogen deposits may stain the recording medium 8 in color. Since the ink of the present invention contains, as an electrolyte, a compound that does not produce halogen ions when ionized, it is possible to suppress the generation of halogen gas and the precipitation of halogen due to electrode reactions caused by voltage application.

On the other hand, in order to stably record images, it is desirable to keep the electrical conductivity of the ink constant; however, if the liquid dispersion medium evaporates during the image recording process, the electrical conductivity of the ink decreases. do. For this reason, it is desirable that the liquid dispersion medium be stable against environmental changes, etc., but by containing a polyhydric alcohol solvent as the liquid dispersion medium and dissolving the electrolyte in it, the electrical conductivity of the ink can be improved. It can be made more stable. This is because if the electrolyte is contained in the polyhydric alcohol solvent, even if the water in the ink evaporates during the image recording process, the polyhydric alcohol solvent remains and is contained in the solvent. This is because it is possible to prevent the electrical conductivity of the electrolyte or ink from significantly decreasing and maintain good sensitivity. During the image recording process, the electrolyte does not generate halogen ions, so halogen gas that is toxic to the human body is not released into the atmosphere due to electrolysis, and the halogen is precipitated as a solid and attached to the recording object. Nor.

Next, a method for recording an image using the ink of the present invention will be explained.

The basic image recording method is that when a voltage is applied to the ink by a pair of electrodes, the adhesive ink stops adhering to the electrode, or the non-adhesive ink starts adhering to the electrode. By using one electrode with a desired pattern as a plate and supplying the ink between it and the opposite electrode, and applying a DC voltage between the pair of electrodes, an image is created according to the pattern of the electrodes. It is something that is made to form.

- In method F, in order for the ink to adhere well to the electrode pattern, the viscosity of the ink is low, and liquids such as water and alcohol have weak cohesive force, making it impossible to obtain suitable adhesion. For this reason, the adhesion of the ink is, for example, 21TII11 on a platinum-plated stainless steel plate placed vertically.
It is preferable that the ink of the present invention be substantially retained on the platinum-plated stainless steel plate when the ink of the present invention is deposited to a thickness of . In addition, the ink of the present invention was sandwiched between two platinum-plated stainless steel plates to make the ink thickness 2 mm, and when the two platinum-plated stainless steel plates were separated from each other with no voltage applied, which It is preferable that the ink adheres to the plate to the same extent.

Furthermore, the ink of the present invention is basically composed of inorganic or organic fine particles and a liquid dispersion medium, and the viscosity of the ink can be arbitrarily adjusted by adjusting the type of fine particles, the particle size, the blending ratio, the type of dispersion medium, etc. It is.

The image forming method using the ink of the present invention can be divided into the following two types depending on the properties of the ink used.

Namely, one type is that the ink has adhesive properties when no voltage is applied, and the adhesive properties disappear when voltage is applied.

In this case, ink adheres to the insulating portion of the plate, forming a desired recorded image.

The other type is that the ink is not sticky when no voltage is applied, but becomes sticky when voltage is applied.

In this case, ink adheres to the conductive portion of the plate, forming a desired recorded image.

Next, the adhesion of ink used in the image forming method will be explained.

Whether the ink is made to have adhesive properties from the beginning or not can be easily controlled by the blending ratio of the materials constituting the ink, the types of constituent materials, etc.

Regarding the mechanism of changing the adhesion of ink by voltage application, the following several cases can be considered.

One is when the adhesion changes due to Coulomb force, and the basic composition of the ink is made up of inorganic or organic fine particles and a liquid dispersion medium, and the mechanism utilizes the difference in the chargeability of the fine particles. thing.

In this case, if the ink is adjusted to have adhesive properties from the beginning and contains fine particles that are likely to be negatively charged,
When a voltage is applied, the ink on the negative electrode side will no longer adhere, and if the adhesion is adjusted to reduce the adhesion and particles that are easily charged positively are included, then the ink on the positive electrode side will no longer adhere when a voltage is applied. In addition, if you make the ink non-adhesive from the beginning and include particles that are easily charged negatively in the form of fine particles, the ink on the positive electrode side will adhere to it when a voltage is applied, causing it to become adhesive. If the ink is adjusted so that it does not occur and contains fine particles that are likely to be positively charged, the ink will adhere to the cathode side when a voltage is applied.

The second mechanism is that the ink electrolyzes when it is energized by applying a voltage, generating gas and changing its tackiness.

In this case, the ink is adjusted to have adhesive properties, and when a voltage is applied, the ink electrolyzes near one electrode or near both electrodes to generate gas, and this gas causes the ink to adhere to the electrodes. It disappears. In order for the ink to electrolyze and generate gas, the electrical resistance of the ink should be low, and preferably the volume resistivity should be 10 5 Ωcm or less. If the volume resistance exceeds 105 Ωcm, the current flow rate will decrease, or a high voltage will be required to prevent a decrease in conductivity, which is undesirable.

The image forming method using the ink of the present invention is considered to be mainly based on one of the above mechanisms, or it is also possible that each mechanism occurs simultaneously. In addition, in the case of ink that changes from adhesion to non-adhesion by voltage application, the transfer of ink to the plate occurs almost entirely in the thickness direction of the part of the ink layer where voltage is applied (hereinafter referred to as bulk transfer). Also, for ink that changes from non-adhesion to adhesion, it may result in bulk movement due to the relationship between the adhesive force at each interface and the cohesive force of the ink, or it may result in partial transfer in which a part of the surface layer of the ink is transferred. It seems that it will.

The ink of the present invention can be an ink that adheres or does not adhere when no voltage is applied, but from the viewpoint of image density, it is preferable for the ink to move in bulk because the density becomes more uniform.

The adhesion of the ink changes due to the above-mentioned mechanism, and when the ink adheres to the anode or cathode, an electrode reaction occurs on or near the electrode, and phenomena that are not related to adhesion control also appear. For example, electrolyte deposition or gas generation that occurs on or near the electrode when a voltage is applied to the ink is caused by the formation of toxic halogen gas on the anode side when a solvent containing an electrolyte that generates halogen ions is used. In addition, colored halogen is generated and deposited on the ZCJJii, colors the electrode surface, and is finally mixed into the image on the recording medium. Additionally, if the electrical conductivity of the ink decreases due to evaporation of the solvent (liquid dispersion medium) used in the ink during the image recording process, the sensitivity of ink adhesion control will decrease, causing problems such as adhesion and non-adhesion on electrodes. Adhesion will not be smooth.

In the present invention, since an electrolyte that does not generate halogen ions is used, ionic conduction can occur without causing the phenomenon described in -F. The electrolyte should preferably have a relatively large overvoltage and be difficult to deposit, and should also have a sufficient electrical conductivity to smoothly control the voltage adhesion of the ink.

A preferred electrolyte that can be used in the ink of the present invention is lithium fluoroborate (LiBFJ).

Sodium hexafluorophosphate (NaPFs), ammonium hexafluorophosphate (N'84PF6)
, sodium acetate ((:1I3COONa), etc.), and can be used alone or in combination with other electrolytes, and lithium borofluoride is particularly preferred.The content is 0.05 parts by weight per 100 parts by weight of the liquid dispersion medium. It is preferable to use it so that the color saturation solution (relative to polyhydric alcohol solvent under image recording conditions) is 0.05 parts.
If the amount is less than 2 parts by weight, the electrical conductivity will not increase, and if the amount is more than 2 parts by weight, the electrolyte that cannot be completely dissolved in the solvent will precipitate, making the ink non-uniform, which is not preferable.

Further, the liquid dispersion medium is preferably one that is not susceptible to changes due to external factors such as evaporation during the image recording process and easily dissolves the electrolyte. Preferred liquid dispersion media contain polyhydric alcohol solvents, and examples of polyhydric alcohol solvents that can be used as the liquid dispersion medium for the ink of the present invention include ethylene glycol, propylene glycol, Diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (for weight average molecules, about 100 to +000
), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl carpitol, ethyl carpitol, butyl carpitol, ethyl carpitol acetate, diethyl carpitol, triethylene glycol monomethyl nityl, triethylene glycol Examples include monoethyl ether, propylene gelcol monomethyl ether, dipropylene glycol, hexylene glycol, and glycerin. These polyhydric alcohol solvents may be used alone or in combination of two or more. The polyhydric alcohol solvent may also be used in combination with another liquid dispersion medium, and the polyhydric alcohol solvent is usually contained in an amount of θ to 100% by weight based on the total liquid dispersion medium in the ink. desirable.

Water is commonly used as other liquid dispersion medium, but it can be selected and used as appropriate depending on the type of adhesion control mechanism involved. For example, triethanolamine,
Formamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-prolidone, 1,3-dimedyl-mitazolidinone, N-methylacetamide,
Ethylene carbonate, acetamide, succinonitrile, dimethyl sulfoxide, sulfolane, furfuryl alcohol, N2N-dimethylformamide, 2-ethoxyethanol, hexamethylphosphoric triamide, 2-nitropropane, nitroethane, γ - Butyrolactone, propylene carbonate, 1,2.6-hexanetriol, etc. alone or a mixture of two of them can be used. The liquid dispersion medium is
It is preferably contained in an amount of 40 to 95 parts by weight, more preferably 60 to 85 parts by weight, per 100 parts by weight of the ink.

It is preferable to use water or something containing water as the liquid dispersion medium because hydrogen gas is easily generated on the negative electrode side. When water and another liquid dispersion medium are mixed, the content of water is preferably at least 11 parts by weight, more preferably at least 5 parts by weight, based on 10 parts by weight of the ink.

Next, other configurations of the ink of the present invention will be explained.

The ink of the present invention is a colloidal sol amorphous solid basically composed of inorganic or organic fine particles and a liquid dispersion medium, and is a non-Newtonian fluid in terms of fluidity. The fine particles in the ink improve the sharpness of the ink and improve the resolution of the image.

If you want to control changes in ink adhesion using Coulomb force, you can use fine particles that are easily charged and knead them in Meitatsu's liquid dispersion medium, for example in a homogenizer, colloid mill, or ultrasonic disperser. Ga obi tK
Charged particles are generated. Particles to which a positive charge is imparted include metal (Au, Ag, C: u) particles,
Sulfides (zinc sulfide ZnS, antimony sulfide 5b2s,
Potassium sulfide (2S, calcium sulfide Gas, germanium sulfide GeS, cobalt sulfide CoS, tin mide SnS, iron sulfide FeS, copper sulfide Cu2S, mangani sulfide/MnS, molybdenum sulfide Mo253, etc.) particles,
Silicic acid (orthosilicic acid H4S i04, metasilicic acid t1
2si03, mesotrisilicate 11□5i205, mesotrisilicate H45r303, mesotetrasilicic acid 116s1401
1) particles, polyamide resin particles, polyamideimide resin particles, etc., and particles to which a negative charge is imparted include iron hydroxide particles, aluminum hydroxide particles, fluorinated mica particles, polyethylene particles, Montmorillonite particles, fluororesin, etc. can be used.

It is also possible to use polymer particles containing various load control agents used as toners in electrophotography.

The size of the fine particles described in 112 is 51' average particle diameter of 100 μm or less, preferably 0.1 μm to 2f) 4 m
Among them, particles with a diameter of 10 μm or less can be used, and such fine particles are contained in the ink at a ratio of IF! to 100 parts by weight of the ink. jfi parts or more, preferably 3 parts by weight to 90 parts by weight
It is contained in an amount of 5 parts by weight, more preferably 5 parts by weight to 60 parts by weight.

In a preferred embodiment of the present invention, in order to control the viscosity of the ink, the above-described polymer soluble in the liquid dispersion medium is added to the ink in an amount of 1 to 90 parts by weight, more preferably 1 to 50 parts by weight per 100 parts of the pupil of the ink. It can be contained in an amount of 1 to 20 parts by weight, particularly 1 to 20 parts by weight. Such polymers include vegetable polymers such as guar gum, locust bean gum, gum arabic, taragant, carrageenan, pectin, mannan, and starch; microbial polymers such as xanthan gum, dextrin, succinoglucan, and curdlan; gelatin, casein, Animal-based polymers such as albumin and collagen; Cellulose-based polymers such as methylcellulose, ethylcellulose, and droxyethylcellulose, or starch-based polymers such as soluble starch, carboxymethyl starch, and methyl starch; Alginic acid-based polymers such as propylene glycol alginate and alginate Semi-synthetic polymers such as polymers and other polysaccharide derivatives; vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, carboxyhinyl polymer, sodium polyacrylate; other polyethylene glycols, Mated ethylene, oxidized Synthetic polymers such as propylene block monomer, alkyd resin, phenol resin, epoxy resin, amino alkyd resin, polyester resin, polyurethane resin, acrylic resin, polyamide resin, polyamideimide resin, polyesterimide resin, silicone resin, etc. alone or in combination The above can be used in combination. It is also possible to use greases such as silicone grease and liquid polymers such as polybdenum.

In the case of ink that generates gas by electrolysis, the fine particles contained in the ink include colloidal silicon, fluorocarbon, titanium oxide, carbon black, fluorocarbon, etc. in addition to those listed above.

In a preferred embodiment of the ink of the present invention, in consideration of the viscoelastic properties of the ink, the fine particles are preferably swellable fine particles capable of retaining the liquid dispersion medium described above. Examples of such swelling fine particles include Na-montmorillonite, Cra-montmorillonite, 3-octahedral synthetic smectite, Na-hectolite, Li-hectolite, and Na-duolite.

Examples include fluoride clouds 1'f) such as Na-tetrasilicic mica and Li-teniolite, synthetic mica, and silica.

The above-mentioned fluorinated mica can be represented by the following general formula (1).

General formula (1): % formula %) In the formula, W is Na or Li, X and Y are Mg'', Fe
2+.

Six-coordinate ions such as Ni'', Mn'', AI'', Fe''+ Li+, Z is 813◆, Si'÷Ge'',
pe3+, B54T or a combination thereof (AI”/
It represents a cation with a coordination number of 4, such as Sj'9. The average particle diameter of the swellable fine particles is preferably 100 μm or less, more preferably 1 to 20 μm, and preferably 10 μm or less.

The ink of the present invention may contain colorants such as carbon black and other dyes and pigments that are generally used in the fields of printing and recording, if necessary. When the ink contains a coloring material, the content of the coloring material is preferably 0.1 to 40 parts by weight, more preferably 1 to 20 parts by weight per 100 parts by weight of the ink. Further, instead of or together with the coloring material, a coloring compound that develops color upon application of voltage may be contained. In addition, the ink may contain an electrolyte, thickener, thinner, surfactant, etc. that impart conductivity. Further, it is also possible to make the fine particles themselves serve the function of a coloring material.

An image recording method using the ink of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram schematically showing a recording apparatus that can perform image recording using the ink of the present invention. In this figure, an ink carrying roll 1 is a member that has a cylindrical shape and rotates in the direction of the arrow claw. be. The roll 1 is preferably made of a conductive material such as aluminum, copper, or stainless steel. On the surface (cylindrical surface) of the ink carrying roll 1, ink 2, which is a recording material, is formed to have a uniform thickness by a coating roll 9 rotating in the direction of arrow E. The material constituting the surface of the roll l, which is the ink carrying surface, may be any material that can form a desired layer of ink 2 on the surface (by conveying the ink 2 by rotation in the direction of the arrow claw). If so, it can be used without any particular restriction. More specifically,
A conductor made of metal such as stainless steel is preferred. The ink carrying roll 1 is connected to one end of a DC power supply 11.

The surface of the ink carrying roll 1 made of such a material is
Although it may be a smooth surface, it is preferable that the surface be appropriately roughened (for example, to a roughness level of IS) in order to further improve the transport and support properties of the ink 2.

A plate 4 wound around a plate roll 3 is in contact with ink 2 on the surface of the ink carrying roll 1. The plate roll 3 is rotating in the direction of arrow B in the opposite direction to the roll 1. For example, as shown in FIG. 2, the plate 4 includes a base material 4a made of a conductive material such as metal, and a desired pattern 4b made of an insulating material provided thereon.

As for the material of the base material 4a, its surface may be a metal such as aluminum, copper, stainless steel, platinum, gold, chromium, nickel, steel copper, or carbon, or a conductive polymer, or a metal filler dispersed in various polymers. used. The material for the pattern 4b is a thermal transfer recording material or an electrophotographic toner image.

Vinyl-based polymers and other natural and synthetic polymers may be used.

In this way, by applying a voltage between the plate 4 and the ink carrying roll 1 from the power supply 11, the adhesion of the ink 2 that comes into contact with the conductive portion of the plate 4 changes, and due to the difference in adhesion, the ink 2 is applied onto the plate. is deposited in a pattern to form an ink image. The voltage of the power supply 11 is practically 10 to 10
A DC voltage of 0 V, more preferably 5 to 50 V is preferable, and an AC bias voltage (I
By further applying OV -100V), the image quality can be made even sharper.

In Figure 1, the plate 4 side is the anode and the ink carrying roll 1 side is the cathode, but depending on the properties of the ink used, the plate 4 side
The side may be used as a cathode and the roll 1 side may be used as an anode.

Specifically, the voltage from the power supply II is preferably applied between the respective rotation axes of the printing roll 3 and the ink carrying roll 1.

The thickness of the layer of ink 2 formed on the surface of the ink carrying roll 1 is (the thickness of the ink carrying roll 1 and the coating roll 9
This roll 1 is different depending on the size of the gap between the plate roll 3-L, the flow characteristics or viscosity of the ink 2, the material or roughness of the surface of the ink-carrying roll 1, or the rotation speed of the roll 1). At the ink transfer position facing the pattern plate 4, it is preferably approximately 0.001 to b.

If the layer thickness of the ink 2 is less than 0.00 mm, it will be difficult to form a uniform ink layer on the ink carrier roll 1. On the other hand, if the ink layer thickness exceeds 100 mm, it becomes difficult to convey the ink 2 while keeping the surface layer of the ink layer (the layer in contact with the conductive pattern plate 4) at a uniform circumferential speed, and the ink carrying roll Communication between 1 and the conductive pattern plate 4 is also easily eliminated.

Next, while pressing the ink image on the plate 4 with the plate 4, press the arrow C
It is transferred to the plan cylinder 5 which rotates in the direction, and further transferred to the plan cylinder 5L.
The ink image is transferred onto a recording medium 7 (paper, cloth, metal sheet, etc.) that passes between an impression cylinder 6 that rotates in the direction of the arrow while being in pressure contact with a plan cylinder 5. An image 8 corresponding to the above ink image is formed thereon.

In some cases, the ink image on the plate 4 may be directly transferred onto the recording medium 7 without providing the plan cylinder 5, but it is better to provide the plan cylinder 5 because the contact between the plate and the recording medium is This is preferable because it prevents deterioration due to abrasion of the plate and allows an image with the same pattern (positive image) as the plate to be obtained on a non-recording medium.

It is also possible to use a plate having an insulating film on which an image-like conductive pattern is formed by discharge breakdown on a base material made of a conductive material. Furthermore, it is also possible to use a plate having a photographic image in which a conductive pattern of a silver image is formed by depositing silver particles on a base material made of a conductive material.

In the example shown in Fig. 1, the plate 4 is used while being housed in a cylindrical plate roll 3, but the plate 4 is used as an electrode as it is, and ink is applied to the plate and the plate and counter electrode are connected. Even if a voltage is applied with the ink sandwiched between them, an ink image can be formed on the printing plate.

Furthermore, since the ink of the present invention can be controlled by voltage adhesion, the ink inside the device can be cleaned by applying voltage when changing the ink, so it is possible to configure a recording device that is easy to maintain. .

〔Example〕

Hereinafter, the present invention will be explained according to examples.

Example 1 200g of glycerin and lithium teniolite (LiM
After kneading 40 g of g2Li (Si40,.)F2) in a homosinizer at a rotation speed of 10,000 rpm for 30 minutes, 200 g of water and LiBF4 Jog were added,
A gray amorphous solid colloidal vine ink was prepared by mixing on a roll mill. , After applying the above ink to a thickness of about 2 mm on a platinum-plated stainless steel plate measuring 1 cm x 1 cm, a platinum-plated stainless steel plate of the same size as the surface was placed on top of the ink, and then applied under no voltage. When the two platinum-plated stainless steel plates were separated by gradually increasing the distance between the two platinum-plated stainless steel plates, ink was found to have adhered to almost the entire area on both platinum-plated plates.

Next, a voltage of 30V was applied to both platinum-plated stainless steel plates with a 2mm thick ink layer sandwiched between them, one of which was used as a cathode (earth) and the other as an anode, and while this voltage was being applied, the two plates were When the two platinum-plated stainless steel plates were separated by gradually increasing the distance between them, all the ink adhered to the anode side electrode.
There was no ink adhesion on the cathode side. Further, the electrical conductivity of the ink was about 100 Ωcm.

Next, image formation was performed using the printing machine shown in FIG.

As the ink carrying roll 1, a platinum-plated stainless steel cylindrical roll (surface roughness IS) with a diameter of 30++ on was used, and as the plate roll 3, an iron cylindrical roll with a diameter of 30IIIn and whose surface was hard chromium plated was used.

A plate 4 was wound around this plate roll 3, and the above-described ink material was introduced between the ink carrying roll 1 and the coating roll 9. The ink carrying roll 1 was rotated in the direction of the arrow at a circumferential speed of 5 mm/sec, and the gap with the coating roll 9, which was a cylindrical roll made of surface Teflon comb rotating in the direction of the arrow E, was controlled.
By rotating at mm/sec, the ink layer thickness on the ink carrying roll 1 was controlled to 0.2 mm. The plate roll 3 was rotated in the direction of arrow C at a circumferential speed of 5 mm/sec.

When printing was carried out without applying any voltage from the DC power source 11 of this printing machine, no image-like printed material was obtained. When printing was carried out under the condition where a DC voltage of 30 V was applied, many prints with sharp image quality were obtained.

Note that during the printing process, no gas was observed from the ink-carrying roll 1 of the anode and no deposits were observed on the roll.

Furthermore, no decrease in sensitivity of adhesion control due to changes in electrical conductivity was observed.

Example 2 600g of glycerin, 3DOg of water, carbon black (
Pigment) (manufactured by Capot, USA, "Sterling SRJ
') and 100 g of polyvinyl alcohol (manufactured by Nippon Gosei Kagaku T, "Gohsenol KPO8J") were added and kneaded at 80°C to dissolve the polyvinyl alcohol, and then 100 g of lithium duolite and LiBF4 were added.
30 g was added and mixed in a roll mill to obtain an amorphous solid ink.

When printing was performed using the above ink in the same manner as in Example 1, a large number of printed matter with sharp image quality was obtained as in Example 1.

Example 3 Parts by weight (average particle size 1 micron or less) Carbon black 6° (manufactured by Cabot, USA, trade name Sterling R) Water
140 glycerin
280゛ Water, glycerin, and carphone blank were mixed at 411r using an attritor to prepare a mixed solution, and this mixed solution was mixed with colloidal hydrous silicate and 650 g of NaPF using a kneader to obtain the ink of the present invention.

When this ink was used for printing in the same manner as in Example 1, a large number of prints with sharp image quality were obtained as in Example 1.

Example 4 Part by weight water
50 Propylene Glycol 50
Polyvinyl alcohol 20 (product name Gohsenol GL-03, manufactured by Nippon Gosei Chemical Co., Ltd.) Carbon black 10 (product name Sterling R1, manufactured by Cabot, USA) Sodium borate (decahydrate) 0.9 (Na2B, 0
．． -10820) Sodium hydroxide IN aqueous solution 4,5LiB
F420 After heating the above components to 80°C and mixing them uniformly, the mixture was cooled and printed using the ink according to the method of Example 1.
As in Example 1, many prints with sharp image quality were obtained.

Comparative Example 1 When an ink was prepared using KCILog instead of 410 g of LIBF in Actual jj'fi Example 1 and printing was performed in the same manner, chlorine gas was detected from the ink carrying roll 1.

Comparative Example 2 Kl 2 was used instead of 420 g of LiBF in Example 4.
When 0 g of ink was prepared and printing was performed in the same manner, coloring, which was thought to be due to iodine precipitation on the ink carrying roll 1, was observed in the ink image 8 on the recording medium.

(Effects of the Invention) As explained above, in the ink used in the new image forming method that records an image by changing the adhesion by applying a voltage, the ink contains an electrolyte that does not generate halogen ions when ionized. By doing so, it is possible to obtain high-quality printed matter without generating toxic helocene gas or adhering colored halogen deposits to the paper.

Furthermore, by including a monohydric alcohol solvent as a liquid dispersion medium, stable printing can be performed without reducing the electrical conductivity of the ink.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing an example of an apparatus for forming an image using the ink of the present invention, and FIG. 2 is a schematic side view of a plate used for forming an image using the ink of the present invention.
- It is a schematic perspective view showing an example. 1... Ink carrying roll 2... Ink 3...
Plate roll 4... Plate 5... Plan cylinder
6... Impression cylinder 7... Recorded object 8
... Ink image 9 ... Coating roll 10.
...Ink reservoir 11...Power supply 4a...
・Base material 4b...pattern

Claims (1)

[Scope of Claims] 1. An image recording ink consisting of fine particles and a liquid dispersion medium whose adhesion changes when a voltage is applied through a pair of electrodes and adheres to one of the electrodes, and when ionized in the liquid dispersion medium. An image recording ink characterized by containing an electrolyte that does not generate halogen ions. 2. The ink according to claim 1, wherein the liquid dispersion medium contains a polyhydric alcohol solvent. 3. The electrolyte is lithium borofluoride (LiBF_4)
, sodium hexafluorophosphate (NaPF_6),
Ammonium hexafluorophosphate (NH_4PF_6
), sodium acetate (CH_3COONa), and one or more compounds selected from the group consisting of sodium acetate (CH_3COONa). 4. The compound is lithium borofluoride (LiBF_4)
The ink according to claim 3, characterized in that it is.