JPH0462087A - Printing device - Google Patents

Abstract

PURPOSE:To enable positive control of an electrification electric charge amount and subsequently, the obtaining of a high-quality image by using whichever method, attaching a printing plate on an elastic plate cylinder or providing a printing plate consisting of an insulating pattern on an elastic, electrically conductive base. CONSTITUTION:A plate cylinder 5 on which a printing plate is mounted consists of an elastic member. Any kind of material can be used for the plate cylinder 5, if it is elastic. For example, rubber material such as silicon rubber, any elastic material containing carbon or Ni powder is dispersed in a rubber material or an elastic graphite consisting of graphite granules bound by a resin binder is used. The plate cylinder 5 preferably has an elasticity equal to a rubber hardness of 50 deg. to 95 deg., more preferably 60 deg. to 90 deg.. The printing plate 10 to be mounted on the plate cylinder 5 is composed of, for example, an insulating pattern 10b formed on an electrically conductive base 10a with a surface of aluminum or copper. Further, the printing plate 10 used consists of, for example, only a conductor(metal) shaped like a plate or aluminum or copper foil attached to a support of PET or polyimide.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing device for printing using ink whose adhesion changes with the application of voltage.

[Conventional technology]

Conventional printing methods using ink include lithographic printing, letterpress printing, and gravure printing.

These methods require dampening water for buttering the ink in the image and non-image areas on the plate, and require complex operations to control the ink adhesion of the resin on the plate surface. There were some points that needed improvement.

[Problem to be solved by the invention]

Therefore, the present applicant has previously proposed an image forming apparatus that prints using ink whose adhesion changes depending on voltage application (Japanese Patent Application No. 63-12617, etc.). Since such an image forming apparatus can control the amount of ink transferred by the amount of electrical charge, there is no need to adjust the amount of ink using a large number of rollers as in conventional printing machines. Furthermore, since the printing process is relatively simple, the device configuration is also relatively simple.

In the image forming apparatus described above, one of a pair of electrodes is used as a plate, the ink is sandwiched between the pair of electrodes, and the amount of ink transferred is controlled by applying electricity between the electrodes. There was a problem in that the state of contact through the contact affected the local amount of electrical charge, resulting in unevenness in the resulting image.

An object of the present invention is to provide a printing device that overcomes the above problems.

In other words, it is a printing method that has a relatively simple configuration, can obtain images of good quality at high speed, and can also ensure more reliable contact between the plate and the other electrode, and more reliably control the amount of energized charge. Provide equipment.

[Means for solving the problem (and action)] The present invention has the following features:
a pair of electrodes, one of which is a plate; means for supplying between the pair of electrodes an ink that changes from adhering to at least one electrode by applying a voltage; and means for applying a voltage between the pair of electrodes. , and a printing device having a transfer means for transferring ink adhered on the plate to a recording medium, characterized in that the plate is attached to an elastic plate cylinder, or the plate is made of a conductive base material. This printing device is characterized in that an insulating pattern is provided on the conductive base material and the conductive base material has elasticity.

According to the present invention, since the plate cylinder that supports the plate or the plate itself has elasticity, contact between the plate and the other electrode is ensured, and the amount of electrical charge can be reliably controlled, resulting in good image quality. images can now be obtained. Note that both the plate and the plate cylinder may have elasticity.

If the plate cylinder is elastic, the plate cylinder can be manufactured according to known rubber processing methods. For example, the method described in the points for selecting rubber materials published by the Japanese Standards Association may be used. Specifically, for example, raw rubber having viscoelastic properties is plasticized and kneaded. Next, heat is applied to create a network bond through a chemical reaction, producing an elastic body. A plate is attached onto this elastic body for use.

When the conductive base material (plate) is elastic, or when both the base material (plate) and the plate are elastic, conductive particles such as conductive carbon or metal powder are added during kneading in the above elastic body manufacturing process. Can be created by dispersing and mixing.

In addition, the elastic graphite body used in the examples described later is obtained by nitrating carbonaceous mesophase and coke produced during the heat treatment process of heavy bituminous materials. Next, this nitride is dissolved in an alkali, and an acid is added to precipitate it, followed by heat treatment and foaming.

This foam is graphitized.

The electrically conductive elastic body may be used as it is as a plate, or may be fixed to a rigid body.

The dimensions and shapes of the elastic body and conductive base material manufactured by the above manufacturing method are not particularly limited, and may be used in a flat or cylindrical shape.

In addition, the hardness of the surface rubber is so” according to JIS standard A.
The angle is preferably 95°, and more preferably 60° to 90°.

(Example〕 Hereinafter, the present invention will be described in detail with reference to the drawings.

In FIG. 1, rollers 1 to 4 are means for supplying ink 8, and roller 4 is configured to form a pair of electrodes with the conductive base material of plate 10.

The material of the surface of the rollers 1 to 3 is not particularly limited, and for example, metal materials such as stainless steel, rubber materials such as silicone rubber, plastic materials, etc. are used.

The surface material of the roller 4, which also serves as one electrode, is not particularly limited as long as it has conductivity; for example, conductors such as aluminum, stainless steel, copper, platinum, resin,
It is made of rubber made of conductive material made by dispersing carbon, Ni, etc. powder, or an elastic graphite made of granular graphite bound with a resin binder.

The plate cylinder 5 on which the plate is mounted is made of an elastic member. The material of the plate cylinder 5 may be any material as long as it has elasticity, such as rubber materials such as silicone rubber, materials in which powders such as carbon or Ni are dispersed in the rubber material, or materials made of granular graphite in resin. An elastic graphite body bonded with a binder or the like is used. The elasticity of the plate cylinder 5 has a rubber hardness of 50.
Preferably, the angle is between 95° and 95°. More preferably 60°~
It is best to use one with a 90° angle.

As shown in FIG. 2, the plate 10 mounted on the plate cylinder 5 is constructed by forming an insulating pattern 10b on a conductive base material 10a whose surface is made of, for example, aluminum, copper, or the like. For example, it may take the form of a plate using only a conductor (metal, etc.), a foil made of aluminum or copper glued onto a support such as PET or polyimide, or carbon or nitrogen in a resin.
A material prepared by dispersing powder such as i or the like can be used. The thickness of the conductive base material is arbitrarily determined depending on the quality of the conductive material, but in order not to offset the elasticity of the plate cylinder 5, the thickness of the conductive base material is 500 μm or less, and further 200 μm or less.
It is preferable to make it less than m.

The insulating pattern formed on the conductive base material can be formed using, for example, an insulating ink containing a polymer or wax used in a conventional thermal transfer method, a toner used in an electrophotographic method, or the like. Alternatively, a polymerizable polymer precursor layer is formed on a conductive base material, and a pattern image consisting of a polymerized portion and an unpolymerized portion is formed on the precursor layer by applying light and/or heat to the precursor layer. It is also possible to remove the unpolymerized portions by etching or the Beer-Apart method to form an insulating pattern consisting of the polymerized portions. In addition, any material that can be coated with an electrically insulating material may be used, such as crayon, marker, paint, or other electrically insulating material.

As described above, the plate having the insulating pattern formed on the conductive base material is attached to the plate cylinder made of the elastic member.

The ink 8 used for printing using the apparatus of the present invention is an ink whose adhesion changes depending on the polarity of the applied voltage,
For example, ink may be sticky when no voltage is applied, and the stickiness disappears when a voltage is applied. When this ink is energized by applying a voltage, the ink electrolyzes to generate scum, and its adhesion changes from adhesive to non-adhesive.

In this case, the ink is adjusted to have adhesive properties,
When a voltage is applied, ink or gas is generated near one electrode, and this gas prevents ink from adhering to the electrode. In order for the ink to electrolyze and generate gas, the ink contains a solvent such as water, alcohol, glycol, or a solvent in which an electrolyte is dissolved. The electrical resistance of the ink is preferably as low as possible, and the volume resistivity is preferably 10 5 Ω·Cl 11 or less. If the volume resistance exceeds 10 5 Ω·cm, the amount of current flowing decreases or a high voltage is required to prevent the amount of current flowing, which is not preferable.

This ink has a weak cohesive force with liquids such as water and alcohol, and does not have suitable adhesiveness. In addition, the ink can be applied, for example, to a platinum-plated stainless steel plate held vertically.
It is preferable that the ink be substantially retained on the platinum-plated stainless steel plate when the ink is deposited to a thickness of LL1. In addition, the ink is sandwiched between two platinum-plated stainless steel plates to reduce the thickness of the ink to 2+nm.
Preferably, when two platinum-plated stainless steel plates are separated from each other with no voltage applied, ink adheres to both plates to the same extent.

This ink basically consists of a liquid dispersion medium and inorganic or organic fine particles. The fine particles in the ink make it easier to cut the ink and improve the resolution of the image. The ink controlled by the present invention is an amorphous solid of a colloidal sol and is a non-Newtonian fluid in terms of fluidity.

The liquid dispersion medium used in this ink includes ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetro-diethylene glycol, and polyethylene glycol (weight average molecular weight, approximately 10
0 to 1,000), ethylene glycol methyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl calpitol, ethyl calpitol, butyl calpitol, ethyl calpitol, triethylene glycol Recol 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, dimethylsulfoxide, sulfolane, furfuryl alcohol, N,N-dimethylformamide, 2-ethoxyethanol, hexamethylphosphoric triamide (hexamethyl It is possible to use a single medium or a mixed medium of two or more of phosphoric acid triamide), 2-nitropropane, nitroethane, γ-butyrolactone, propylene carbonate, 1゜2.6-hexandrol, dipropylene glycol, hexylene glycol, etc. I can do it. The liquid dispersion medium 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.

More preferred liquid dispersion media include water, alcohols such as methanol and ethanol, solvents with hydroxyl groups such as glycerin, ethylene glycol and propylene glycol, or solvents in which electrolytes such as sodium chloride and potassium chloride are dissolved. In particular, it is preferable to use water or something containing water as the liquid dispersion medium because hydrogen scum is likely to be generated on the negative electrode side. When water and another liquid dispersion medium are mixed, the content of water is preferably 1 part by weight or more, more preferably 5 parts by weight or more, based on 100 parts by weight of the ink.

In a preferred embodiment, in order to control the viscosity of the ink, the above-mentioned polymer soluble in the liquid dispersion medium is added to the ink material in an amount of 1 to 90 parts by weight, more preferably 1 part by weight, based on 100 parts by weight of the ink material.
It can be contained in a proportion of from 1 to 50 parts by weight, particularly from 1 to 20 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 droxyethyl cellulose; starch polymers such as soluble starch, carboxymethyl starch, and methyl starch; alginic acid polymers such as propylene glycol alginate and alginate; Semi-synthetic polymers such as polymers and other polysaccharide-based conductors; vinyl-based polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, carboxyvinyl polymers, sodium polyacrylate; other polyethylene glycol, ethylene oxide, propylene oxide blocks, etc. Synthetic polymers such as polymers, alkyd resins, phenolic resins, epoxy resins, amino alkyd resins, polyester resins, polyurethane resins, acrylic resins, polyamide resins, polyamideimide resins, polyesterimide resins, silicone resins, etc., singly or in combination of two or more It can be used as It is also possible to use greases such as silicone grease and liquid polymers such as bolybdenum.

The fine particles contained in the ink include metals (Au, A
g, [;11, etc.) particles, sulfides (zinc sulfide ZnS, antimony sulfide 5b2s3. potassium sulfide 2S, calcium sulfide CaS, germanium sulfide GeS, cobalt sulfide cos, tin sulfide SnS, iron sulfide FeS, copper sulfide Cu2S, sulfide manganese MnS, molybdenum sulfide MO253, etc.) particles, silicic acid (orthosilicic acid 14SiO
4, Metasilicic acid H2S1O, Mesotrisilicate H2S12
05, mesotrisilicate 114sf03, mesotetrasilicic acid H6
5iJ+ + etc.) particles, boramid resin particles, polyamideimide resin particles, iron hydroxide particles, aluminum hydroxide particles, fluoride mica particles, polyethylene particles, montmorillonite particles, fluororesin, silica, carbon fluoride, titanium oxide,
Carbon black, carbon fluoride, and various polymer particles used as electrophotographic toners can also be used.

The above-mentioned fine particles have an average particle diameter of 100 μm or less,
Preferably, particles with a diameter of 0.1 μm to 20 μm, especially 10 μm or less, can be used, and such fine particles are present in the ink in an amount of 1 part by weight or more, preferably 3 parts by weight to 90 parts by weight, based on 100 parts by weight of the ink. More preferably, it can be contained in an amount of 5 parts by weight to 60 parts by weight.

In a preferred embodiment of the ink, in consideration of the viscoelastic properties of the ink, it is preferable to use swellable fine particles capable of holding the above-mentioned liquid dispersion medium as the fine particles in the ink. Examples of such swelling fine particles include Na-montmorillonite, Ca-montmorillonite, 3-octahedral synthetic smectite, Na-hectolite, Li-hectolite, Na-teniolite, Na-tetrasilicic mica, and Li-teniolite. There are fluorinated mica, synthetic mica, silica, etc.

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

General formula (1) % formula %) In the above formula, W is Na or Li, X and Y are Mg2+F
6-coordinate ions such as e", Ni", Mn2", Fe", Li+, Z is AI", Si", Ge", p e 3 +
, B3+ or a combination thereof (A I 3 + / S
represents an ion with a coordination number of 4, such as r 4 + ).

The average particle diameter of the swellable fine particles is preferably 100 μm or less, preferably 1 to 20 μm, and preferably 10 μm or less.

If necessary, the ink can contain colorants such as dyes and pigments that are generally used in the fields of printing and recording, such as carphone black. When the ink contains a coloring material, the content of the coloring material is o, based on 100 parts by weight of the ink.
i to 40 parts by weight, more preferably 1 to 20 parts by weight. Further, instead of or together with the colorant, a color-forming compound that develops color upon application of voltage may be contained.

In addition, electrolytes that give conductivity to ink, thickeners,
It can contain a thinning agent, a surfactant, etc. Furthermore, it is also possible for the above-mentioned fine particles themselves to also function as a coloring material.

The ink 8 having the above-mentioned structure is put between the rollers 1 and 2 as shown in FIG. 1, and the ink 8 is supplied onto the plate 10 by the rollers 1 to 4. At the same time, a voltage is applied between the plate 10 with the ink 8 interposed therebetween and the roller 4. Then, the adhesion of the ink 8 in contact with the conductive base material 10a of the plate changes to non-adhesion, thereby forming an ink image only on the insulating pattern tob of the plate. The applied voltage at this time is practically preferably a DC voltage of 3 to 100V, more preferably 5 to 80V, and an AC bias voltage may be supplementarily applied.

In FIG. 1, the plate 10 side is the cathode and the roll 4 side is the anode, but this may be reversed depending on the properties of the ink used.

Next, the ink image on the plate is transferred onto a recording medium 11 (paper, cloth, metal sheet, etc.) that passes between the impression cylinders 6 rotating in the direction of arrow F while being in pressure contact with the plate. An ink image is formed as shown in FIG. In some cases, the ink image on the plate may be transferred once to an intermediate transfer body such as a plan cylinder, and then transferred again to the recording medium.

After repeating image formation as described above and completing the required number of sheets, if unnecessary insulating patterns 10b and ink images remain, the remaining ink is scraped off from the conductive base material 10a using a web of the cleaner 9 or the like. By removing it, a new image can be formed. However, the cleaner 9 is movable so as to be in a non-contact state with the conductive base material 10a during image formation, and to be in contact with the conductive base material 10a during cleaning. Cleaning methods include scraping with a plate, transporting a heated paper or other removal material to melt and remove the insulating pattern forming material, and removing with a web impregnated with a solvent.

The apparatus of the present invention comprises the above-mentioned Leete 9 (base material 10).
Although it is preferable to have a means for removing the pattern on a), the present invention is not limited thereto, and the cleaning may be performed manually by an operator. Moreover, if a flexible conductive sheet or the like is wrapped around the conductive base material 10a and a pattern is formed, the sheet can be thrown away.
Pattern removal is also possible.

Further, when cleaning is performed using the cleaner 9 and manual cleaning described above, the roller 4 is made not to come into contact with the plate on the plate cylinder 5.

(Example 1) An apparatus having the following configuration based on FIG. 1 was prepared.

Roller ~3: 34mmφ, width 80LIII11, stainless steel roller 4: 34mm1Iφ, width 80mm, conductive rubber with carbon dispersed in silicone rubber attached to a stainless steel shaft (manufactured by Meiji Kasei Rubber), rubber hardness 75 degrees Copper plate 5: 80 mmφ, width 80 mm, stainless steel shaft with silicone rubber pasted, rubber hardness 75 degrees Plate 10: Conductive base material 10a: Copper plate, thickness 0.1 mm
Insulating pattern 10b = photoresist forming Gap between rollers 1 and 2: 0.5 mm Between rollers 2 and 3 //: 0.1 mm Roller 4 contacts rollers 3 and 5 Rollers 1 to 5 are driven by motor ink 8 200 g of glycerin, lithium taeniolite (average particle size 2.5 μm, LiMg2L1 (
Si40□. ) F2) 140 g, and a cyan pigment (5upranol Cyanin manufactured by Bayer AG) as a coloring agent.
e 7BF) 10g in a homogenizer at 10 revolutions
' A gray amorphous solid sol ink was prepared by adding 200 g of water and mixing on a roll mill after kneading for 30 minutes at rpm.

Electrical connection of the conductive base material 10a of the plate 10 was made via a stainless steel shaft (not shown) of the plate cylinder 5.

After the ink 8 was added as shown in FIG. 1, the rollers 1 to 6 were rotated at a circumferential speed of 100 mm/sec in the direction of arrow ANF. After visually confirming that the roller 4 was uniformly coated with the ink 8, the roller 4 was brought into contact with the plate. At this time, a DC voltage of 30 V was simultaneously applied using the conductive base material 10a of the plate as a cathode (grounded) and the roller 4 as an anode.

As a result, the ink adhered only to the insulating pattern of the conductive substrate 10a, and a large number of prints with high image quality and no sharp fogging were obtained. This process was repeated several times, and a large number of prints were also obtained.

(Comparative Example 1) Printing was performed in the same manner as in Example 1 except that the plate cylinder 5 was made of stainless steel.

Although many prints with sharp image quality were obtained, fogging occurred along the longitudinal direction of the roller 4, although some of the prints were turned over several times. The cause is roller 4 and plate 10.
This seems to be because the contact between the two was sometimes insufficient, and the voltage was not applied uniformly and stably.

(Example 2) Plate cylinder 5 Stainless steel plate making 10: Conductive base material 10a: Conductive rubber with carbon dispersed in silicone rubber (manufactured by Meiji Kasei Rubber Co., Ltd.), thickness 2 mm, rubber hardness 75 degrees Insulation pattern: Photoresist above Printing was carried out in the same manner as in Example 1 except for this.

As in Example 1, a large number of prints with good image quality were obtained.

(Example 3) Conductive base material 10a: Elastic graphite sheet (manufactured by Kota Oil Co., Ltd.),
Printing was carried out in the same manner as in Example 2 except that the thickness was 2 mm and the rubber hardness was 85 degrees.

Good printing similar to Example 1 was achieved.

(Example 4) A blank cylinder is provided between the plate (and plate cylinder) and the recording medium as an intermediate transfer means, and the ink on the plate is once transferred to the plan cylinder.
After the image was transferred to the recording medium, printing was performed on the recording medium 11 that was sent between the blank cylinder and the impression cylinder. Other configurations and conditions were the same as in Example 1.

As in Example 1, a large number of good printed materials were obtained.

〔Effect of the invention〕

As explained below, according to the present invention, by having an elastic member on the plate side, the contact between the plate and the other electrode is made more secure, uniform voltage application is realized, and good quality is achieved without fogging. Provided is a device that can print a large number of images at high speed.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the apparatus of the present invention, and FIG. 2 is a schematic diagram showing an example of a plate used in the apparatus of the present invention. Roller 2: Roller 3: Roller 4: Roller (electrode) 5: Plate cylinder 6: Impression cylinder 8: Ink 9: Cleaner 0: Plate Oa: Conductive base material Ob: Insulation pattern 1: Recorded object

Claims (1)

[Claims] 1. A pair of electrodes, one of which is a plate; means for supplying between the pair of electrodes an ink that changes from adhering to at least one electrode to non-adhering by applying a voltage; A printing device comprising a means for applying a voltage between electrodes and a transfer means for transferring ink deposited on the plate onto a recording medium, characterized in that the plate is mounted on an elastic plate cylinder. Device. 2. A pair of electrodes, one of which is a plate; means for supplying between the pair of electrodes an ink that becomes non-adhesive to at least one electrode by applying a voltage; applying a voltage between the pair of electrodes; and a transfer means for transferring ink adhered on the plate to a recording medium, the plate having an insulating pattern provided on a conductive base material,
A printing device characterized in that the conductive base material has elasticity.