JPH02285385A - Image formation - Google Patents

Abstract

PURPOSE:To remove ink on the surface of a roll without human intervention by applying a voltage to ink remaining in a device from a pair of members one of which is a blade-like conductive member, reducing adhesion of the ink and removing the ink. CONSTITUTION:An ink carrying roll 1 and a plate roll 3 are provided as a pair of conductive members, and a pair of conductive members one of which is a blade-like conductive member, is composed of a cleaning blade 11, a blanket cylinder 5, a cleaning blade 12, the plate roll 3, a cleaning blade 13 and the ink carrying roll 1. Through the use of ink 2 which never attaches to a pair of electrodes when they apply a voltage, an image forming device including the pair of conductive members 1 and 3 forms an image. After that, the pair of conductive members one of which is a blade-like conductive member applies a voltage to the ink 2 remaining in the device to reduce the adhesion of the ink 2. Consequently, the ink 2 remaining in the image forming device can be removed without human intervention.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming method in which ink can be cleaned.

[Prior Art] Printers using various recording methods, such as laser beam and
Printers, inkjet printers, thermal transfer printers, wire-toe printers and daisy-foil printers are known.

The present applicant also previously proposed a recording method in which pattern-like adhesiveness is chemically imparted to ink and recording is performed by utilizing the difference between the adhesiveness and non-adhesiveness of this ink (Japanese Patent Application Laid-open No. 1986-111001: -302
No. 79).

However, the above recording method is not suitable for large-volume printing due to cost and other considerations.

Conventionally, methods suitable for high-volume printing include lithography,
In these conventional printing methods, such as letterpress printing and gravure printing, ink is first applied to the surface of several successive rolls, and once the thickness of the ink has become sufficiently thin, the plate is removed. It is generally applied to

The present applicant also proposed a printing method (Japanese Patent Application No. 12617/1983) in which printing is performed by applying a voltage to ink to change the adhesion of the ink, as an application for a printing method.

[Problem 8 to be Solved by the Invention] By the way, if the ink remaining on the roll surface after printing is not removed immediately, the ink will dry and the rolls will adhere to each other, causing trouble in the next printing. Conventionally, ink on the surface of a roll could not be completely removed without manual intervention. Therefore, cleaning the ink after printing is a very troublesome task.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an image forming method and an image forming apparatus that can remove ink remaining in an image forming apparatus without manual intervention.

[Means for Solving the Problems] The image forming method of the present invention uses an ink whose adhesion changes depending on the polarity of an applied voltage to form an image using an image forming device including at least one pair of conductive members. applying a voltage to the ink remaining in the image forming apparatus from a pair of conductive members, one of which is a blade-shaped conductive member;
The method is characterized by comprising a cleaning step of removing the ink by reducing the adhesion of the ink.

Further, an image forming apparatus according to the present invention includes a plurality of conductive members capable of carrying ink, and is characterized in that a power source is provided between at least one pair of the conductive members.

[Detailed Description of Aspects of the Invention] The image forming method of the present invention utilizes the property that when a voltage is applied to an adhesive ink by a pair of electrodes, the ink does not adhere to the electrodes, thereby forming an image. This removes ink remaining in various parts of the printer.

The present invention will be explained below with reference to one drawing.

The image forming apparatus used in the image forming method of the present invention has at least one pair of conductive members. In the image forming apparatus shown in FIG. 1, an ink supporting roll 1 and a printing roll 3 are a pair of conductive members. Further, a pair of conductive members, one of which is a blade-shaped conductive member, is a cleaning blade 11.
and plan cylinder 5, cleaning blade 12 and plate roll 3
, a cleaning blade 13 and an ink carrying roll l.

In the image forming apparatus shown in FIG. 1, the ink supporting roll l is a member that has a cylindrical shape and rotates in the direction of arrow A. The roll l is an ink-compatible roll l preferably formed of a conductive material such as aluminum, copper, or stainless steel.
Ink 2, which is a recording material, is formed to have a uniform thickness on the surface (cylindrical surface) by a coating roll 9 rotating in the direction of arrow E. As for the material constituting the surface of the roll 1, which is the ink-bearing surface, a desired ink 2 is applied onto the surface (by conveying the ink 2 by rotation in the direction of the arrow).
Any material that can form a layer can be used without any particular restrictions. More specifically, a conductor made of metal such as stainless steel is preferred.

The surface of the ink carrying roll 1 made of such a material is
Although it may be a smooth surface, from the point of view of further improving the conveyance and carrying capacity of the ink 2, a moderately rough surface (for example, JIS 80
The ink 2, which preferably has a surface roughness of about IS (601), is replenished into the ink reservoir 10.

The printing plate 4 on the plate roll 3 rotating in the direction of arrow B comes into contact with the ink 2 on the surface of the ink-bearing roll 1, and the printing plate 4
The ink of ink 2 is transferred to the image area to form an ink image. As the printing plate 4, conventionally known ones can be used. For example, an offset printing plate, a gravure printing plate, a letterpress plate, etc. can be used. Further, the printing plate 4 is composed of a conductive part and an insulating part, and by applying a voltage between the printing plate 4 and the ink carrying roll l, for example, the ink does not adhere to the conductive part of the plate, and the ink is applied only to the insulating part. Alternatively, an additional roll may be inserted between the printing plate 4 and the ink carrying roll l to form a uniform ink layer, or the rolls may be used as a pair of conductive members. A voltage may be applied.

Next, the ink image on the printing plate 4 is transferred to the blank cylinder 5 rotating in the direction of arrow C while being in pressure contact with the printing plate 4, and the ink image on the blank cylinder 5 is further transferred to the blank cylinder 5 while being in pressure contact with the blank cylinder 5. An image corresponding to the above-mentioned ink image is transferred onto a recording medium 7 (paper, cloth, metal sheet) passing in the F direction between impression cylinders 6 rotating in the direction F, and an image corresponding to the above-mentioned ink image is transferred onto the recording medium 7 (paper, cloth, metal sheet). is formed.

In some cases, the ink image on the first plate 4 may be directly transferred onto the recording medium 7 without providing the blank cylinder 5, but the surface material of the blank cylinder 5 can prevent wear and deterioration of the plate. Furthermore, an image having the same pattern as the plate can be obtained on the recording medium.

Now, if the ink layer on the blank cylinder 51 plate 4 and ink carrying roll 1 is not removed after printing is completed, the ink layer will dry and cause problems in the next printing.

In the above printing process, in the present invention, cleaning is carried out by using a blade made of a conductive material that can be pressed and detached from the plate cylinder, blank cylinder, ink support roll, and other rollers to which ink adheres. can do.

In other words, the blade-shaped conductive member is a blade-shaped member (cleaning blade) as shown in the schematic perspective view of FIG. 3 and the schematic cross-sectional view of FIG. 13), which is arranged at a certain angle so as to be in electrical contact with the roller (the ink-bearing roll L in FIGS. 3 and 4) through the ink 2, and so as to scrape off ink residue on the roll. It is something that can be cleaned. The tip of the cleaning blade 13 has a sharp angle. In other words, the shape of the cleaning blade 13 may be such that the tip that touches the roller is sharp and can be arranged parallel to the length direction of the roller at a certain angle.The cleaning blade 13 does not come off the roller except during cleaning. It is best to have a detachable means so that it can be removed. The cleaning blade 13 is electrically conductive, and as shown in FIGS. 3 and 4, the cleaning blade 13 is electrically conductive.
A voltage can be applied between the When a voltage is applied between the roller 1 and the cleaning blade 13, the voltage is applied to the ink residue 2 remaining on the roller, changing the adhesion of the ink and causing it to adhere onto the cleaning blade 13. The polarity of the applied voltage is set according to the characteristics of the ink used, so that the ink adheres to the cleaning blade by applying the voltage.

In the present invention, the cleaning blade 13 has two functions. One is a function to physically scrape and remove ink from the roll, and the other is a function to change the adhesion of ink by electrical action and remove it from the roll. When removing ink using the former function, there is no need to apply voltage to the cleaning blade, and the tip thereof may be in contact with the roller surface, whereby ink residue on the roller is physically scraped off. When removing ink using the latter function, the cleaning blade does not come into direct contact with the roller, but is electrically connected through the ink. That is, the cleaning blade and the roller have a pair of electrodes, and by applying a voltage to the ink, the adhesion of the ink can be changed and the ink can be removed from the roller.

According to the cleaning blade (hereinafter simply referred to as blade) that can be used in the method of the present invention, when the blade and roller are not in electrical contact, cleaning of ink residue by scraping by physical action (physical When the blade and roller are electrically connected via ink, cleaning can be performed by moving the ink due to changes in the adhesive properties of the ink itself (electrical cleaning), making it possible to clean ink residue very efficiently. I can do it.

A device for cleaning can be composed of a blade-shaped conductive member and voltage application means, but the voltage application means basically includes a DC power source and means for connecting the power source to the blade and the roll. If the roll itself is made of conductive material, the power supply can be connected directly to the roll shaft, or if only the surface of the roll is conductive, the power supply can be connected directly to the roll surface. It is preferable that the roller be equipped with a means that can contact the roll surface with a constant pressure during physical leaning, such as a mechanism that can be pressed against the roll surface using a spring or the like. It is preferable that the blade is provided with an inching means such as a screw so that the distance between the blade and the roll can be set to a predetermined distance.These may be done electrically or manually.

Next, the blade surface of the blade has sharp etches, but by making the tip an insulator, physical cleaning and electrical cleaning can be performed at the same time, making cleaning of residual ink more efficient. It is also a turning part.

For example, as shown in Figure 5, by using an insulating blade at the tip and a conductor on the other blade surface, the ink residue scraped off by the blade tip will stick to the conductor part of the blade surface due to the applied voltage. The properties of the ink will change and it will stick, causing more ink to be drawn away from the roller and onto the blade.

That is, in the present invention, the blade-shaped conductive member is
The blade itself does not need to be electrically conductive, as long as a conductor is formed on the blade surface, and a portion of the blade surface, particularly the tip, may be an insulator.

The smaller the distance between the conductive part of the blade surface and the roller, the more efficient the continuity of physical and electrical cleaning is, and it is preferable. 0.01~1
It is preferable to set the distance from the roller surface by about 0.00 mm, and of course, the distance may be set as appropriate depending on the amount and type of ink.

To make the tip of the blade insulative and the other blade surfaces conductive, either make the blade itself with an insulator and coat the blade surface other than the tip with a conductive material, or conversely, make the blade itself conductive. This can be done by covering the tip with an insulator.

Further, the arrangement angle of the blade with respect to the roller may be about 45° with respect to the roller surface.Although the tip of the blade may be pressed against the roller, it may be arranged at a certain distance due to ink residue or the like.

Materials that can be used for the blade include conductors such as aluminum, copper, stainless steel, zinc, platinum, iron, and gold, but as mentioned above, the blade itself is an insulator and a part of the blade surface is a conductor. In this case, the blade is made of insulating resin such as silicone, Teflon, urethane, styrene, acrylic, or epoxy, and the conductor that forms part of the blade surface is aluminum, copper, stainless steel, or
Zinc, platinum, iron, gold, etc. may be used.

Practically speaking, the power source for the voltage applied during cleaning is preferably a DC voltage of 3 to 100 V, more preferably 5 to 80 V, and a high frequency (10 fiz - 100 kllz) AC bias voltage (IOV to 100 V) is further applied. By doing so, the cleaning effect can be partially enhanced.0Usually,
1r used to transfer ink to the roll! , may be as high as the source voltage.

The cleaning procedure may be performed as follows.

After printing is completed (after the entire printing process is completed and the image on the roller has been microscopically transferred, etc.), contact the blade to which no voltage is applied to the roller, rotate the roller one or more revolutions, and remove the roller. Scrape off any ink residue on the surface. The peripheral speed of rotation of the roller at this time is 0.5~
A speed of about 500 cm/s is recommended. After scraping, stop the roller rotation.

Remove the blade from the roller while keeping the ink residue scraped on the blade in electrical contact with both the roller surface and the blade. Next, gradually remove the blade from the roller while applying voltage to the blade. As a result, no ink residue remains on the roller.

Also, after printing is finished, do not let the blade make electrical contact with the roller, but keep a distance from the roller so that it comes into contact with ink residue, and rotate the roller at least once at a circumferential speed of about 0.5 to 5OOc/S. The remaining ink on the roller can also be removed by gradually moving it away from the roller.

Furthermore, when using the blade shown in the fifth column, even if the roller and the blade come into physical contact, they do not make electrical contact, so a voltage is applied while pressing the blade against the roller with a certain amount of pressure.

This is preferable because physical cleaning and electrical cleaning of residual ink can be performed simultaneously while the roller continues to rotate.

The above-described cleaning method according to the present invention can be applied to a printing process using ink whose adhesion changes depending on the application of voltage, and where ink residue remains on the ink-carrying roll and may affect the quality of one image. It can be suitably used for cleaning plate rolls, plan cylinders, etc. Furthermore, even if residual ink exists on the flat plate rather than on the roll, cleaning can be carried out by moving the blade along the flat plate using a drive means suitable for the purpose.

That is, the cleaning method of the present invention can be used in any printing process as long as a voltage can be applied between a member having a conductive blade surface and a surface on which ink remains, and thus the cleaning method can be used in any printing process. Ink will no longer adhere to the roller again, and no ink will remain on the roller during cleaning. Therefore, there is less fog on the recording paper than when using a conventional cleaning roller, and cleaning is also easier. Furthermore, in the cleaning method of the present invention, in addition to mechanically removing residual ink, the adhesive properties of the ink itself are utilized by applying voltage, so the ink supply surface or transfer surface is roughened. Ink residue can be removed very efficiently even when

Next, further explanation will be given with reference to FIG. In FIG. 1, numerals 11, 12, and 13 are conductive blades for cleaning the plan cylinder, plate, and ink carrying roll, respectively, and are preferably made of a conductive material such as aluminum, copper, or stainless steel. Further, the distance between the blade and the roll and the nip pressure can be adjusted to desired distances and pressures. In this way, the power supply (10
4, 105, 106), the adhesion of the ink in contact with the conductive portion changes, and the difference in adhesion causes more of the cleaned ink to be deposited on the blade. After cleaning, remove the blade from the roller and press '7! By turning off the power source, any remaining ink on the roller can be removed. The voltages of power supplies 104, 105 and 106 apply to the ink roll 3.
The voltage may be approximately the same as the voltage of the power supply 103 used for transferring the image, that is, practically 3 to 5 volts, or even 5 volts.
A DC voltage of ~80v is preferred, and a high frequency
By further applying an alternating current bias voltage (tovNlOoV) of 0 kHz), the cleaning effect can be further enhanced.

In Figure 1, the blade side is the anode and the roller side is the cathode, but depending on the properties of the ink used, the anodes may be reversed.Also, if a cleaning blade is attached to the plan cylinder as shown in Figure 1, The plunger cylinder must be made of an electrically conductive material, but if it is not attached, it may be made of an insulating member.

Next, other requirements for carrying out the image forming method of the present invention will be explained.

In FIG. 1, the plate 4 may have 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, 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 can also be used. Further, the shape of the plate is not limited to a flat surface, and may be a roll shape, a curved surface shape, or a polygonal shape.

The shape of the ink application member is not limited to a roll, and a blade-like application member may be used, and the shape of the conductive member is not limited to a roll, but a plate-like conductive member may be used.

The plate 4 wound around the first plate roll 3 is in contact with the ink 2 on the surface of the above-mentioned ink support roll l, but the plate 4 is made of a conductive material such as metal, for example, as shown in FIG. A desired pattern 4b made of an insulating material is provided on a base material 4a.

As the material of the base material 4a, aluminum, copper, stainless steel, platinum, gold, chromium, nickel, steel copper, carbon, etc., or conductive polymers or various polymers in which metal fillers are dispersed are used. Materials for pattern 4b include thermal transfer recording materials (mainly wax and resin),
Electrophotographic toners, vinyl polymers, and natural or synthetic polymers are used.

In this way, by applying a voltage between the plate 4 and the ink support roll 1 from the power supply 103, the adhesion of the ink 2 that comes into contact with the conductive portion of the plate 4 changes, and the difference in adhesion causes the ink 2 to be applied onto the plate. It is deposited in a pattern to form an ink image. The voltage of the power supply 103 is practically 3 to 10
A DC voltage of 0 V, more preferably 5 to 80 V is preferable, and by further applying a high frequency (loIz to 100 kllz) AC bias voltage (10 to 100 V), the quality of one image can be made even sharper.

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

Specifically, the voltage from the power source 103 is preferably applied between the respective rotation axes of the printing roll 3 and the ink carrying roll l.

The thickness of the layer of ink 2 formed on the surface of the ink-compatible roll 1 is (the thickness of the ink-compatible roll 1 and the coating roll 9).
the size of the gap, the fluidity or viscosity of ink 2,
Although it varies depending on the material or roughness of the surface of the ink carrying roll 1 or the rotational speed of the roll l, the ink transfer position B where the roll l faces the pattern plate 4 on the plate roll 3 is approximately 0.001. It is preferably about 100 m1, more preferably 0.001 to 10-10.

If the layer thickness of the ink 2 is less than 0.001 mm, it becomes difficult to form a uniform ink layer on the ink-supporting 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. Support roll 1 and conductive pattern plate 4
It is no longer easy to connect electricity to the device.

If the ink 2 contains water (water-soluble ink, emulsion ink), it can be changed from adhesive to non-adhesive by applying a voltage and used in the image forming method of the present invention.

Regarding the mechanism by which the ink changes from adhesive to non-adhesive due to voltage application, the following several cases can be considered.

(1) When the adhesion changes due to Coulomb force when a voltage is applied, the basic composition of the ink is one consisting of inorganic or organic fine particles and a liquid dispersion medium, and one that takes advantage of the difference in the chargeability of the fine particles. It is.

In this case, if the ink contains fine particles that easily charge negatively, the ink will not adhere to the negative electrode side when a voltage is applied, and if the ink contains fine particles that easily charge positively, the ink will not stick to the anode side when a voltage is applied. Ink on the electrode side will no longer adhere.

(2) When the ink electrolyzes and generates gas due to the application of voltage, and the adhesion changes. In this case, the ink generates gas near the electrode due to the voltage application, and this gas causes the ink to adhere to the iQ. I won't. In order for the ink to electrolyze and generate gas, the ink contains a solvent such as water, alcohol, or glycol, or a solvent in which an electrolyte such as sodium chloride or potassium chloride is dissolved. The lower the electrical resistance of the ink, the better, and the volume resistivity is preferably 10 8 Ω·cm or less. When the volume resistance exceeds 10 5 Ω·CI, the amount of current flowing decreases, or a high voltage is required to prevent the amount of current flowing from decreasing.

(3) When energization by voltage application causes a change in the crosslinked structure of the ink due to an electrochemical reaction or a change in the dissociation state of the electrolyte, resulting in a change in adhesion; in this case, at least part of the crosslinked structure of the ink is changes and becomes non-adhesive. Alternatively, the dissociation state of the electrolyte changes and becomes non-adhesive.

The mechanism by which the ink changes from adhesive to non-adhesive due to voltage application is thought to be due to any of the above (1), (2), and (3).

It is also possible that two or more mechanisms (3) occur simultaneously. In addition, in the case of ink that changes from adhering to non-adhering when voltage is applied, the transfer of ink from the plate involves almost all movement in the thickness direction of the part of the ink layer to which voltage is applied (hereinafter referred to as bulk movement). ), also non-adhesive →
Regarding ink that adheres and changes, there may be bulk movement due to the relationship between adhesive force and cohesive force of ink at each interface, or partial transfer where a part of the ink surface layer is transferred.
Since the cleaning method of the present invention removes the entire residual ink, it is preferably used for ink that moves in bulk.

The ink used is sticky when no voltage is applied,
It may be either non-adhesive or non-adhesive, and from the viewpoint of image density, it is preferable for the ink to move in bulk, as the density will be uniform.

The ink that adopts the above mechanisms (1) and (2) will be explained below.

If the ink used in the present invention is a low-viscosity liquid such as water or alcohol, the cohesive force is weak and suitable adhesion cannot be obtained.The viscosity of the ink is a shear rate of 10 rad/g,
At a temperature of 25°C, lOI to 1O10 poise, and even 1
04 to 10" poise is preferred, and the ink used in the present invention has, for example, a 2 mm thick ink applied to a vertically erected platinum-plated stainless steel plate.
It is preferable that the ink is substantially retained on the platinum-plated stainless steel plate in an environment of a temperature of 25°C and a humidity of 60%, and the ink is sandwiched between the two platinum-plated stainless steel plates. When the thickness of the plate is 2cm and two platinum stainless steel plates are separated from each other at a speed of 5c@/sec with no voltage applied, ink adheres to both plates to the same extent. Preferably.

Inks employing mechanisms (1) and (2) are composed of, for example, inorganic or organic fine particles and a liquid dispersion medium. The fine particles in the ink make it easier to cut the ink and improve the resolution of the image. The ink used in the present invention is amorphous and non-Newtonian in fluidity.

If the change in ink adhesion is due to Coulomb force, charged particles or easily charged particles may be used as all or part of the particles, and kneaded in a liquid dispersion medium described below, such as in a homogenizer, colloid mill, or ultrasonic disperser. As a result, charged particles are generated. Particles to which a positive charge is imparted include metal (Au, 8g, Cu, etc.) particles, sulfides (zinc sulfide ZnS, antimony sulfide 5blS3,
Potassium sulfide KtS, calcium sulfide CaS, germanium sulfide GeS, cobalt sulfide Cog, tin sulfide S
nS, iron sulfide FeS, copper sulfide Cu, S, manganese sulfide MnS, molybdenum sulfide 1iot33, etc.) particles, silicic acid (orthosilicic acid 1.3io, metasilicic acid H, 5i)
03. Mesonisilicic acid tlJi*Os, Mesonisilicic acid H
45i303, mesotetrasilicate HsSi401I, etc.) particles, polyamide resin particles, polyamideimide resin particles, etc., and particles to which a # charge is imparted include iron hydroxide particles, aluminum hydroxide particles, fluoride particles, etc. mica particles, polyethylene particles, montmorillonite particles,
Fluororesin or the like can be used. Furthermore, polymer particles containing various load control agents used as toners for electrophotography can also be used.

The above-mentioned fine particles have an average particle diameter of tOO4m or less,
Preferably, 0.1 to 20 parts can be used, and in particular, 0.1 to 10 parts can be used, and such fine particles can be added to the ink at a tg per 100 parts by weight of the ink.
The amount is preferably 3 parts by weight to 90 parts by weight, more preferably 5'! It can be contained in an amount of rEm parts to 6° parts by weight.

In addition, the liquid dispersion medium used in the ink includes ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol (total average molecular weight of about 10
0-1000), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl calpitol, ethyl calpitol, butyl calpitol, ethyl calpitol acetate, diethyl calpitol, triethylene glycol monomethyl ether, triethylene Glycol monoethyl ether, propylene glycol monomethyl ether, glycerin, triethanolamine, formamide, dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N-methylacetamide, ethylene carbonate, acetamide , succinonitrile, dimethyl sulfoxide, sulfolane, furfuryl alcohol,
N,N-dimethylformamide, 2-ethoxyethanol, hexamethylphosphoric triamide (hexamethylphosphoric triamide), 2-nitropropane, nitroethane, γ-butyrolactone, propylene carbonate,
1,2,6-hexandriol, dipropylene glycol, hexylene glycol, etc. can be used alone or in a mixed medium of 2M or more. The amount of the liquid dispersion medium is 40 to 95 parts by weight, more preferably 60 parts by weight, based on 100 parts of the ink.
It is preferable to contain up to 85 parts by weight.

In addition, in order to control the viscosity of the ink, 1 to 90 parts by weight, more preferably 1 to 50 parts by weight, particularly 1 to 20 parts by weight of the above-mentioned polymer soluble in the liquid dispersion medium is added to the ink based on 100 parts by weight of the ink material. It can be contained in a proportion of parts by weight. Such polymers include plant-based 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, and casein. , animal polymers such as albumin and collagen; cellulose polymers such as methyl cellulose, ethyl cellulose, and hydroxyethyl cellulose; starch polymers such as soluble starch, carboxymethyl starch, and methyl starch; alginic acid polymers such as propylene glycol alginate and alginate; Other semi-synthetic polymers such as polysaccharide derivatives; vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, carboxyvinyl polymer, sodium polyacrylate; other polyethylene gelcol, ethylene oxide, propylene oxide block copolymers , alkyd resin, phenol resin, epoxy resin, aminoalkyd resin, polyester resin, polyurethane resin, acrylic resin, polyamide resin, polyamideimide resin, polyesterimide resin, silicone resin, and other synthetic polymers are used alone or in combination of two or more. be able to. It is also possible to use greases such as silicone grease and liquid polymers such as polybutene.

If the change in ink adhesion is due to the generation of gas due to electrolysis, the liquid dispersion medium should be water, alcohols such as methanol or ethanol, solvents with hydroxyl groups such as glycerin, ethylene glycol, propylene glycol, or chloride. A solvent in which an electrolyte such as sodium or potassium chloride is dissolved is preferably used. The contents of the liquid dispersion medium and fine particles are the same as those described above. In particular, when water or a liquid containing water is used as a liquid dispersion medium, hydrogen gas is easily generated on the cathode side, which is preferable.When water and another liquid dispersion medium are mixed, the water content is It is preferably 1 part by weight or more, more preferably 5 parts by weight or more and 99 parts by weight or less based on 10 parts by weight.

In the case of ink that generates gas through electrolysis, the fine particles contained in the ink include, in addition to those previously fried, silica, carbon fluoride, and titanium oxide.

Carbon brauke etc. are used.

In a preferred specific example of the ink, considering the viscoelastic properties of the ink, it is preferable to use in-type fine particles that can hold the liquid dispersion medium in the particles for all or part of the fine particles. For example, Na-
Montmorillonite.

Ca-montmorillonite, 3-octahedral synthetic smectite, Na-hectolite, Li-hectolite, Na-
Taeniolite, Na-tetrasilicic mica and 1,i
-There are fluorinated mica such as taeniolite, synthetic mica, and shinoka.

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

General formula (1) % formula %) In the formula, W is Na or Li, X and Y are Mg", Fe"
◆6 such as Ni”, Mn”, AI” dispute, Fe”, Li dispute, etc.
Coordination ion, 2 is AI", Si", Ge"+Fe"J"
or a combination thereof (represents a cation with a coordination number of 4 with the Al''/Si' linkage).

l11fI! The average particle diameter of the l-type fine particles is 0.
1 to 20 t■, even 0.8 to 15 ru■, especially 0.8
The content of ma mechanical fine particles, which is preferably 8 μ-, may be the same as the content of fine particles described above, but
00 parts by weight, preferably 8 parts by weight to 60 parts by weight,
11 It is also preferable to use particles having electrical charges on their surfaces.

The ink 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 colorant, the content of the colorant is 11 parts by weight per 100 parts by weight of the ink.
．． 1 to 40 parts by weight, more preferably 1 to 20 parts by weight,
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. Furthermore, it is also possible for the above-mentioned fine particles themselves to also function as a coloring material.

In order to obtain the ink described above, for example, a liquid dispersion medium and fine particles may be mixed by a conventional method.

Next, the ink that adopts mechanism (3) described above will be explained.

As the ink used in the present invention, an ink containing a liquid dispersion medium and a crosslinked structure substance or polymer electrolyte that holds the liquid dispersion medium can be used.

The term "crosslinked substance" here refers to a substance that can form a crosslinked structure by itself, or a substance that forms a crosslinked structure by adding other additives (for example, a crosslinking agent made of inorganic ions such as borate ions). A substance that makes it possible to

Further, the term "crosslinked structure" refers to a three-dimensional structure having "tachibana-kake bonds".

In the ink used in the present invention, this "pink bond" may be an ionic bond, a hydrogen bond, or a van der Waals bond (or a combination of two or more of these).
It may be configured by

In the ink used in the present invention, the above-mentioned "crosslinked MIJ structure" is sufficient as long as it can obtain the desired liquid dispersion medium retention property. That is, this crosslinked structure may be, for example, a net-like, honeycomb-like, or spiral structure, and may not be a regular structure.

In the ink used in the present invention, various inorganic or mechanical solvents that are liquid at room temperature can be used as the liquid dispersion medium, but they have relatively low volatility (e.g., equivalent to water). , or lower) is preferably used.

When a hydrophilic dispersion medium such as water or a water-containing dispersion medium is used as the liquid dispersion medium, a hydrophilic (natural or synthetic) polymer or the like is preferably used as the crosslinked structure substance.

Examples of such hydrophilic polymers include guar gum,
Plant-based polymers such as locust bean gum, gum arabic, taragant, carrageenan, pectin, mannan, and starch; Microbial polymers such as xanthan gum, dextrin, succinoglucan, and kartran; Animal-based polymers such as gelatin, casein, albumin, and collagen. Cellulose-based polymers such as methylcellulose, ethyl cellulose, and hydroxyethylene cellulose, or starch-based polymers such as soluble starch, carboxymethyl starch, and methyl starch, propylene glycol alginate,
Semi-synthetic polymers such as alginic acid polymers such as alginates and other polysaccharide derivatives; Vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, carboxyvinyl polymers, and sodium polyacrylate; other polyethylene glycols Synthetic polymers such as ethylene oxide, propylene oxide block copolymers, etc. are preferably used alone or in combination of two or more as necessary.

These wood-loving polymers are usually 0.2 to 50 parts by weight, particularly 0.5 to 30 parts by weight, per 100 parts by weight of the liquid dispersion medium.
It is preferable to use i parts.

Another form of the ink is a polymer electrolyte, which is a polymer having a dissociative group in its polymer chain. Examples of substances that dissociate and become polymer ions when dissolved in wood include natural polymers such as alginic acid and gelatin; and those synthesized by introducing dissociative groups into synthetic polymers such as polystyrene sulfonic acid and polyacrylic acid. be.

Among polymer electrolytes, in order to obtain a wide range of changes in adhesion when energized, it is necessary to use acids such as proteins.
Preferred are amphoteric polyelectrolytes that can also be dissociated as a base.

On the other hand, when using a dispersion medium consisting of an oil such as mineral oil or an organic solvent such as toluene as the liquid dispersion medium, for example, a metal salt of stearic acid such as aluminum stearate, magnesium stearate, zinc stearate;
Other metal soaps made of similar metal salts of fatty acids such as valmitic acid, myristic acid, and lauric acid, or hydroxypropyl cellulose derivatives, dibenzylidene D-
Organic substances such as sorbitol, sucrose fatty acid ester, dextrin fatty acid ester, etc. are preferably used alone (same as the above-mentioned wood-philic polymers) or in combination of two or more as necessary.

When using the above-mentioned wood-philic polymers or metal soaps, the retention of the liquid dispersion medium and the film-forming properties of the ink depend on the amount of these or the combination of these with the liquid dispersion medium. changes to some extent. These amounts,
Alternatively, it is somewhat difficult to unambiguously determine the composition of the combination, but in order for an ink consisting of a liquid dispersion medium and a crosslinked structure substance or a polymer electrolyte to have adhesive properties, it is necessary to It is preferable to increase the amount of solvent, or to lower the degree of crosslinking when using a crosslinked structure substance.

The ink that adopts the mechanism described in (3) has the above-mentioned liquid dispersion medium and a crosslinked structure substance or a polymer electrolyte as essential components, but also contains dyes and pigments or colored fine particles as necessary. A coloring compound that develops color when energized, or an electrolytic substance that imparts desired conductivity to the ink and generates heat when the ink is energized, and if necessary, a fungicide. It may contain additives such as preservatives.

As the colorant, dyes and pigments generally used in the fields of printing and recording, such as carbon black, can be used without particular limitations.

Further, fine particles of an inorganic compound such as colloidal silica, titanium oxide, tin oxide, etc. may be added for the purpose of improving the rigidity of the image.

In order to obtain an ink consisting of the above-mentioned components, for example, a liquid dispersion medium such as water, a crosslinked structure substance consisting of a hydrophilic polymer, etc. (if necessary, a crosslinking agent, a coloring agent, an electrolyte, etc.) and/or It is easy to uniformly mix the polymer electrolyte with heating to form a viscous solution or dispersion, and then cool it to gel.

In addition, when using colored particles such as toner particles as a coloring agent, it is better to add the colored particles after mixing the crosslinked structure material or/and polymer electrolyte and the liquid dispersion medium while heating to make them uniform. Preferably, or in this case, it is also particularly preferable to mix at around room temperature to prevent agglomeration of toner particles, etc.

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

Example 1 (Preparation of ink) 200 g of glycerin and lithium taeniolite
w L i (S i 40H0) F8. Average particle size 2
．． 5ILs) 40 g in a homogenizer at 1 rotation speed.
After kneading at 0,000 rpm for 30 minutes, 200 g of water was added and mixed on a roll mill to prepare a gray amorphous solid colloidal sol ink.

After applying the above ink to a thickness of approximately 21 mm on a platinum-plated stainless steel plate of 1 cs x 1 am, place the platinum-plated stainless steel plate of the same size on top of the ink, and then apply the two sheets under no voltage. When the two platinum-plated stainless steel plates were separated by gradually widening the interval between the platinum-plated stainless steel plates, ink was found to have adhered to almost the entire area on both platinum-plated stainless steel plates.

Next, a voltage of +30 V was applied to one of the two platinum-plated stainless steel plates sandwiching the two-layer ink layer between them, with one side serving as the cathode (earth) and the other serving as the anode.

When the two platinum-plated stainless steel plates were separated by gradually increasing the distance between them while applying this voltage, all the ink adhered to the anode side electrode and the cathode side There was no ink adhesion.

(Printing process) 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 m was used, and as the printing roll 3, an iron cylindrical roll with a diameter of 30 m5 and whose surface was plated with hard chrome was used. A plate 4 made of an aluminum plate buttered with a vinyl resin was wound around the plate roll 3, and the above-described ink material was introduced between the ink-bearing roll 1 and the coating roll 9.

The ink support roll 1 is rotated in the direction of the arrow at a circumferential speed of 5 am/see, and the gap between the coating roll 9 and the coating roll 9, which is a cylindrical roll made of surface Teflon rubber and rotating in the direction of the arrow E, is controlled. mm/se
The thickness of the ink layer on the ink carrying roll 1 was controlled to 0.2 mm by rotating the roll at a speed of c.

Plate roll 3 is 511II in the direction of arrow B! It was rotated at a circumferential speed of l/SeC. Also, at this time, clean blade 1
1.12.13 were fixed so as not to contact the ink or the roller.

When I printed with no voltage applied from the DC power supply +03 of this printing machine, no image-like printed matter was obtained, but when I printed with a DC voltage of 30V applied from the DC power supply +03, A large number of prints with sharp image quality were obtained (at this time, the plate roll 3 was used as a cathode and the ink carrying roll 1 was used as an anode).

(Cleaning of residual ink) After printing is completed, the cleaning blades 11, 12 and 13 are brought into contact with each roller to start the rotation of each roller and scrape off the ink on the roller surface until the roller has completed one rotation or more. When finished, the rollers stopped rotating. Next, the cleaning blade is separated from the roller to the extent that it does not come into contact with the roller, but at this time the roller and cleaning blade are in electrical contact with each other due to the ink layer that was scraped off.
Next, each roll was rotated again while applying a DC voltage of 30 V from the power supplies 104, 105, and 106, and most of the ink residue on each roller was removed by separating the cleaning blades 11, 12, and 13 from the rollers. .

Example 2 After printing in the same manner as in Example 1 using the ink and printing machine, cleaning was performed as follows.

Bring the cleaning blades 11, 12 and 13 into contact with the ink layer without touching the roller surface, and turn on the power supply ports 4 and 1.
From 05, 106, the rollers were rotated for more than 11 times while being energized at 30V, and after rotating for more than one revolution, the cleaning blades 11, 12, 13 were further separated from the rollers while continuing to be energized, and most of the ink residue on each roller was removed. Ta.

Example 3 600g of glycerin, 300g of water, carbon black (
Pigment) (Manufactured by Cabot, USA, "Sterling SRJ"
50 g and 100 g of polyvinyl alcohol (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., "Gohsenol KPO8J") were added, and the mixture was kneaded at 80°C to dissolve the polyvinyl alcohol.
00g was added and mixed in a roll mill to obtain an amorphous solid ink.

When the above ink material was tested in a manner similar to that used in Example 1, similar results were obtained.

Example 4 <Ink material> Part by weight Water glycerin Among the above materials, water, glycerin, and carbon black were mixed in 411r in an attritor to create a mixed solution, and then this mixed solution and colloidal hydrated silicate were mixed in a kneader. death,
Got the ink.

Using this ink, printing was performed in the same manner as in Example 1 using the same printing machine as in Example 1, and then cleaning was performed in the same manner as in Example 1, and the same results as in Example 1 were obtained.

[Effects of the Invention] The image forming method of the present invention in which the adhesion of ink changes depending on the polarity of the applied voltage and forms an image using this change has excellent environmental stability and is very easy to handle. Furthermore, by incorporating a cleaning means, even more excellent image formation can be performed.

That is, according to the present invention, the cleaned ink material does not adhere to the roller again, and the ink does not remain on the roller during cleaning regardless of the smoothness of the roller surface, so there is no fogging of the recording paper. can be reduced.

In addition to the above-mentioned cleaning means, the present invention can also be applied to areas where ink remains, such as cleaning ink adhering to non-image areas on printing plates, and cleaning can be easily performed. The image forming method of the present invention is very useful in printing technology.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing an example of a printing apparatus according to the image forming method of the present invention, FIG. 2 is a schematic perspective view showing an example of a printing plate used in the apparatus shown in FIG. 1, and FIG. FIG. 4 is a schematic perspective view and a sectional view showing the configuration during cleaning by the cleaning blade, and FIG. 5 is a schematic perspective view showing another aspect of the cleaning blade. l... Ink carrying roll 2... Ink 3... Plate roll 4... Plate 4a... Base material 4b... Image pattern 5... Plan cylinder 6... Impression cylinder 7... -Recorded object 8...Ink image 9...Coating roll lO...Ink reservoir 103, 104, 105, 106-...DC power supply 11.
12.13...Cleaning blade 14-...Conductor 15...Insulator

Claims (4)

[Claims] (1) A printing process in which an image is formed by an image forming apparatus including at least a pair of conductive members using ink whose adhesion changes depending on the polarity of an applied voltage, and one of the inks remaining in the image forming apparatus is An image forming method comprising: a cleaning step of removing the ink by applying a voltage from a pair of conductive members that are blade-shaped conductive members to reduce the adhesion of the ink. (2) The method according to claim 1, wherein the tip of the blade surface of the blade-shaped conductive member is an insulator. (3) The method according to claim 1, wherein the ink is removed after the ink is removed by the blade-like conductive member without applying a voltage. (4) The method according to any one of claims (1) to (3), wherein the step of forming an image is based on bulk movement.