JP2002264384A - Anode for electric solidification printing, printing method and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anode for electric solidification printing exhibiting excellent cleaning performance in which cleaning causes no wear nor depression and formation of passivation film is not prevented. SOLUTION: The anode for electric solidification printing is composed of an Fe alloy containing 20 wt.% or more of Cr, 5-15 wt.% of Ni, 1-2 wt.% of Si, 0.9-1.5 wt.% of Mn, 0.1-0.3 wt.% of C, and the remainder of Fe and inevitable impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an anode for electrocoagulation printing, an electrocoagulation printing method, and an electrocoagulation printing apparatus.

[0002]

2. Description of the Related Art Electrocoagulation printing uses an electrocoagulation printing ink (hereinafter referred to as "ink") comprising a polymer which solidifies by electrolysis, a dispersion medium, a soluble electrolyte, a colorant, and the like.
This ink is filled between an anode for electrocoagulation printing having a surface made of stainless steel or the like (hereinafter referred to as "anode") and a cathode having a large number of pin-shaped electrodes arranged independently from each other, and is electrolytically solidified by energization. This is a method in which a plurality of solidified ink dots representing a desired image are formed on the surface of the anode, and the dots are transferred to a printing medium and printed (US Pat. No. 4,895,955).
No. 629). After the dots have been transferred, the anode surface is washed with a washing brush and a washing liquid to remove any coagulated ink remaining on the anode surface.

The mechanism by which the dots of the coagulated ink are formed on the anode surface is as follows. The anode is made of stainless steel, aluminum, etc. that forms a passivation film. A voltage is applied between the cathode and the anode to destroy the passivation film where the voltage is applied. To elute iron ions and alnium ions. As the ink used is one that coagulates with trivalent iron ions or alnium ions, trivalent iron ions and aluminum ions eluted from the anode are mixed into the printing ink to coagulate the ink. .

Conventionally, stainless steel which is inexpensive and easily available has been used for the anode. Stainless steel is Cr
Containing at least about 11% by weight (hereinafter simply referred to as “%”)
e alloy, specifically, Cr: 12 to 20%, Ni:
3 to 10%, Mo: 0.5 to 2.5%, C: 0.03 to
0.09%, with the balance being Fe and unavoidable impurities. In stainless steel, the presence of this amount of Cr suppresses the generation of rust in clean air, and this corrosion resistance is provided by the above-mentioned passivation film that self-heals under various environments. .

[0005]

Such stainless steel is excellent in terms of electrolytic coagulation of the ink, but is not sufficient in terms of hardness, and is subjected to severe conditions after the dots of the coagulated ink are transferred. The washing of the anode surface performed below causes wear and dents, so the surface had to be polished every time the printing time reached about 40 hours. To do so, the printing device must be stopped and the anode must be removed from the printing device. Addition of elements other than Cr to steel has been performed to provide certain properties and to facilitate manufacture. For example, to improve corrosion resistance, N
i, N, Mo; C, N, Ti for enhancing strength; S, Se for enhancing machinability; Ni for increasing moldability and rigidity.

However, when the C content is increased, there is a problem that the passivation of stainless steel is hindered. On the other hand, stainless steel containing a large amount of Ni cannot be completely removed from the anode surface due to poor cleaning properties. There is a problem that a ground is generated, and when printing a multi-color image using a plurality of inks of different colors, the quality of printed matter is deteriorated. Accordingly, an object of the present invention is to provide an anode which does not cause abrasion or dents due to washing, has excellent washing properties, and does not hinder the formation of a passivation film. Another object of the present invention is to provide an electrocoagulation printing method and apparatus capable of obtaining high quality printed matter with high productivity by using such an anode.

[0007]

In order to achieve the above object, an anode according to the present invention is characterized in that Cr: 20% by weight or more,
i: 5 to 15% by weight, Si: 1 to 2% by weight, Mn: 0.
9 to 1.5% by weight, C: 0.1 to 0.3% by weight,
The balance is made of Fe and an Fe alloy consisting of unavoidable impurities. Since the anode of the present invention has the above-mentioned component composition, the anode has sufficient hardness to withstand washing without causing abrasion and dents, and also has excellent washing properties. . Also, the alloy composition does not adversely affect passivation.

The electrocoagulation printing method according to the present invention is a method using the above-described anode according to the present invention, and comprises the following steps:
a) using the anode and the cathode according to the present invention, by passing an electric current through the electrocoagulated printing ink present between the anode and the cathode, and coagulating the electrocoagulated printing ink electrolytically to present a desired image; Forming a dot on the surface of the anode; and b) transferring the dot of the coagulated ink to a printing medium to print an image.

The multicolor electrocoagulation printing method according to the present invention is a method using the above-mentioned anode according to the present invention, and comprises the following steps: a) using the anode and the cathode according to the present invention; Passing an electric current through the electrocoagulated printing ink present during the process to electrolytically coagulate the electrocoagulated printing ink to form dots of the coagulated ink representing a desired image on the surface of the anode; b) dots of the coagulated ink To a non-stretchable endless belt; c) repeating the steps a) and b) a plurality of times using electrocoagulable printing inks of different hues, thereby printing dots of coagulated inks of different hues on the surface of the endless belt. Forming a multicolor image on the surface of the endless belt; and d) transferring the multicolor image to print on a printing medium. .

An electrocoagulation printing apparatus according to the present invention is an apparatus using the above-described anode according to the present invention, and has the following configuration: an anode and a cathode according to the present invention; An ink supply unit for supplying ink; an electric supply unit for electrolytically coagulating the electrocoagulated printing ink by energization to form solidified ink dots representing a desired image on the surface of the anode; and applying the solidified ink dots to the anode. Transfer means for transferring an image from a surface to a printing medium to print an image;
It has.

The multicolor electrocoagulation printing apparatus according to the present invention is an apparatus using the above-described anode according to the present invention, and has the following structure: the anode according to the present invention; a non-stretchable endless belt;
A cathode, an ink supply means for supplying an electrocoagulation printing ink of a different hue between the anode and the cathode, and a coagulation for electrolytically coagulating the electrocoagulation printing ink by energization to represent a desired image A plurality of printing units including an energizing unit that forms dots of ink on the surface of the anode, and a first transfer unit that transfers the dots of the solidified ink from the surface of the anode to the surface of the endless belt; and the plurality of printing units. Second transfer means for transferring a multicolor image formed on the surface of the endless belt by overlappingly transferring dots of solidified inks having different hues onto a printing medium and printing the multicolor image.

In the above-described electrocoagulation printing method and apparatus according to the present invention, since the anode according to the present invention is used,
It is not necessary to frequently interrupt printing for polishing the anode surface, and it is possible to provide a high-quality printed matter free of background with high productivity.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The anode according to the present invention has a Cr: 20
% By weight or more (hereinafter simply referred to as “%”), Ni: 5-1
5%, Si: 1-2%, Mn: 0.9-1.5%, C:
0.1-0.3%, and the balance is composed of Fe and an alloy of unavoidable impurities. In the above alloy composition, Cr must be contained in an amount of 20% or more so that self-repair of the passivation film can be performed sufficiently quickly and undesired elution of Fe ²⁺ ions does not occur. Preferably, 20-30% of Cr is contained. If the content of Ni exceeds 15%, washing of the anode is not sufficiently performed, and an ink film containing non-coagulated ink remains on the anode surface, causing background generation. If less than 5%, sufficient ductility and corrosion resistance cannot be obtained.
It must be included. C, when its content exceeds 0.3%, becomes a hindrance factor of passivation,
If it is less than 0.1%, sufficient hardness cannot be obtained in the anode. Mn is an alloying agent used to define the starting point of destruction of the passivation film, and Si is an alloying agent used to improve corrosion resistance to chlorides.

Preferably, Cr: 25 to 28%, Ni:
8-11%, Si: 1-2%, Mn: 0.9-1.5
%, C: 0.1 to 0.2%, with the balance being Fe alloy containing Fe and unavoidable impurities, particularly preferably Cr: 26.4%, Ni: 9.7%, Si: 1. .0
An Fe alloy containing 8%, Mn: 0.95%, and C: 0.12%, with the balance being Fe and unavoidable impurities is used. Such an alloy has a Brinell hardness of about 225.

After the casting of the Fe alloy,
C., particularly preferably about 1120.degree. C., followed by quenching in water can increase the Brinell hardness to about 325 without impairing passivation. The Fe alloy so treated is austenitic-
It has a ferrite structure.

Next, an electrocoagulation printing method and apparatus according to the present invention using the above-described anode will be described with reference to the drawings. FIG. 1 shows an electrocoagulation printing apparatus 1 according to a preferred embodiment. The apparatus 1 has an anode 3 and a diameter of about 5 mm, which is arranged at a predetermined distance (gap) from the anode 3.
A plurality of 0-μm pin-shaped cathodes 5, an ink supply means 9 for supplying an electrocoagulated printing ink between the anode 3 and the cathode 5 (anode surface), and a desired image by electrolytically solidifying the ink by energization Means for forming dots of coagulated ink on the surface of the anode 3 (not shown), and a non-coagulated ink dot transferred from the non-coagulated ink dots by contacting the web S in the form of a continuous web with the surface of the anode 3. Transfer means 13 for printing an image on S
(For example, an impression cylinder made of polyurethane).
The anode 3 is made of the above-mentioned Fe alloy, has an anode active surface defined by a continuous passive surface,
It travels at a substantially constant speed along a predetermined path.

Further, the apparatus 1 is preferably provided with a coating means 7 for coating the surface of the anode 3 with a coating agent, and for removing the non-coagulated ink from the anode surface prior to the transfer of the coagulated ink and reusing the same. Removal means 1
1 (for example, a rubber squeegee made of a flexible polyurethane),
A cleaning unit 15 is provided for cleaning the anode surface after transfer of the coagulated ink by spraying a cleaning liquid. The coating means 7 weakens the adhesion of the solidified ink to the anode of the dots,
Further, in order to prevent uncontrollable corrosion of the anode, the surface of the anode is coated with microdroplets of an oily substance (for example, an olefinic substance) prior to ink supply.

The anode may be in the form of an endless moving belt as disclosed in US Pat. No. 4,661,222, or disclosed in US Pat. Nos. 4,895,629 and 5,538,601. It is preferred to have the shape of a rotating cylinder as described. The anode, in the form of a rotating cylinder, has a longitudinal axis at its center and rotates at a substantially constant speed about the longitudinal axis, as shown in FIG. Preferably, it is arranged around the anode. Preferably, the anode active surface and the ink are maintained at a temperature of about 35-60 ° C., more preferably about 40 ° C., to increase the viscosity of the coagulated ink in the step of forming the dots of the coagulated ink, and to increase the tackiness in the step of transferring the dots. To promote transcription. For example, the anode active surface can be heated to a desired temperature to provide ink on the heated anode surface and transfer heat from the anode active surface to the ink.

Using an apparatus as described above, electrocoagulation printing is carried out in the following procedure: a) Using an anode and a cathode, the ink is passed through the ink existing between the anode and the cathode, and the ink is electrolyzed. Forming solidified ink dots representing a desired image on the anode surface; and b) transferring the solidified ink dots to a printing medium to print an image.

More specifically, the electrocoagulation printing method preferably comprises the following steps: a1) continuous passivation defining an anodic active surface, moving at a substantially constant speed along a predetermined path. Providing an electrolytically inactive anode having a textured surface, a2) a colloidal dispersion comprising, on said anode active surface, an electrolytically coagulable polymer, a dispersion medium, a soluble electrolyte and a colorant. Forming a large number of dots of a colored coagulation ink representing a desired image by electrocoagulation of said electrolytically coagulable polymer present in the electrocoagulation printing ink comprising: Transferring the dots of colored coagulated ink from the anodic active surface onto the substrate by contacting the dots of ink, thereby printing an image on the substrate.

When using a cylindrical anode rotating at a substantially constant speed about the longitudinal central axis of the anode, step a) or step a2) of the electrocoagulation printing method is as follows. It can be suitably implemented: i) a certain predetermined gap arranged in a plane parallel to the longitudinal axis of the anode and arranged in a line parallel to the longitudinal axis of the anode, electrically insulated from one another and defining a series of corresponding cathode active surfaces; Providing a plurality of electrolytically inactive cathodes spaced from the anode active surface by (electrode gap) and each spaced from each other by at least a distance equal to the electrode gap; ii). Applying an oily substance to the anode active surface to form microdroplets of the oily substance; iii) filling the electrode gap with ink; iv) selecting a plurality of cathodes while rotating the anode. A voltage is applied to the applied cathode, and on the anode active surface coated with an oily substance at a position facing the electrode active surface of the applied cathode, solidification and adhesion of the ink are selectively generated one by one, This forms dots of coagulated ink; and v) removes any remaining non-coagulated ink from the anode active surface.

As described in US Pat. No. 4,895,629, placing the cathodes at a distance equal to or greater than the electrode gap prevents edge erosion of the cathodes. be able to. In addition, as described above, by coating the anode with an oily substance before applying a voltage to the cathode, the adhesion of the dots of the coagulated ink to the anode can be reduced, and uncontrollable corrosion of the anode can be prevented. . Since the passivation film on the anode surface contains a sufficient amount of metal oxide to act as a catalyst, it is not necessary to mix the metal oxide with the oily substance.

Suitable examples of the electrolytically inactive metal that can constitute the cathode include stainless steel, platinum, chromium, nickel and aluminum. The gap defined between the anode and cathode can be from about 50 μm to about 10 μm.
0 μm, and as the electrode gap becomes smaller,
The resulting solidified ink dots are sharp. If the electrode gap is on the order of 50 μm, the cathodes are preferably spaced from one another at a distance of about 75 μm.

The oily substance used for coating the surface of the anode in step ii) is preferably an olefinic substance. The use of an olefinic substance as the oily substance is preferable in that the gas generated as a result of the electrolysis is consumed by the reaction with the olefinic substance, so that no gas is accumulated between the cathode and the anode. Suitable examples of this olefinic material include unsaturated fatty acids such as arachidonic acid, linoleic acid, linolenic acid, oleic acid and palmitoleic acid, corn oil, linseed oil, olive oil, peanut oil, soybean oil and sunflower oil. Such unsaturated vegetable oils. Oleic acid is particularly preferably used. The microdroplets of oily substance formed on the anode surface are:
Generally, the diameter is about 1 to 5 μm.

FIG. 2 shows a partially enlarged printing unit. The oily substance is preferably distributed by the dispensing roller 71.
The supply device 77 supplies the oily substance while rotating the applicator roller 73 and the distribution roller 71 in alignment with each other. The microdroplets transferred from the applicator roller 73 to the distribution roller 71 are transferred from the distribution roller 71 to the surface of the anode 3 by a transfer roller 75 which is in parallel with the distribution roller 71 and engages and rotates in contact therewith. The transfer roller 75 and the anode 3 are engaged with each other in a pressure contact state. Such roller arrangements are disclosed in U.S. Pat.
No. 49,392.

The anodic surface coated with an oleaginous material is preferably polished prior to step iii) above to increase the deposition of microdroplets on the anodic active surface. For example, a rotating brush 8 having a plurality of bristles 81 extending radially can be used. The bristles 81 are made of horse hair and have tips that come into contact with the surface of the anode. The friction created by the bristles contacting the surface as the brush rotates has been found to increase the deposition of microdroplets on the anode active surface.

If the cylindrical anode extends vertically, the above step iii) preferably takes place on the anode active surface from an ink supply means 9 arranged adjacent to the electrode gap 6 at a predetermined height with respect to the anode 3. Ink continuously,
Allow the ink to flow along the anode active surface, and as the anode rotates, the ink is carried to the electrode gap,
Fill the electrode gap. Preferably, the excess ink flowing over the anode active surface is collected and the collected ink is recycled to the ink supply 9.

[0028] The ink used for printing contains a polymer which can be electrolytically solidified, a dispersing medium, a soluble electrolyte and a colorant. As the polymer which can be electrolytically coagulated, generally a linear high molecular weight compound, that is, a polymer having a weight average molecular weight of about 10,000 to about 1,000,000, preferably 100,000 to 600,000 is used. Can be Specific examples of preferred polymers include albumin,
Examples include natural polymers such as gelatin, casein and agar, and synthetic polymers such as polyacrylic acid and polyacrylamide. Particularly preferred polymers are
Acrylamide having a weight average molecular weight of about 250,000
Acrylic acid anionic copolymer, Cyanamide (C
Cost Length 86 (ACCOSTRE) by yanamid Inc.)
NGTH 86). In order to use the polymer as a colloidal dispersion, water is preferably used as a dispersion medium.

[0029] Soluble electrolytes include alkali metal halides and alkaline earth metal halides such as lithium chloride, sodium chloride, potassium chloride and calcium chloride. Of these, potassium chloride is particularly preferred.

As a coloring agent, a dye or a pigment can be used. Preferred dyes are water-soluble dyes,
Duasyn Acid Blac which is commercially available from Hoechst (HOECHST)
k) or Duasin Acid Blue (Duasy
n Acid Blue) or Riedel-DE
HAEN) commercially available anti-coloring cyan
Halodai Blue T. Pina (Anti-Halo Dye Blue T. Pin
a), Anti-Halo Dye AC Magenta Extr
a V01 Pina) and anti-halodioxonol yellow N.I. Pina (Anti-Halo Dye Oxono
l Yellow N. Pina). As the pigment, for example, a pigment commercially available from CABOT CORP. Such as Carbon Black Monarch (registered trademark) 120 (Carbon Black Monarch® 120) for coloring black, or a pigment for cyan is used. Hostaperm Blue B2G or B3G (Permanent Rubin F6B or L6 for magenta coloring)
B (Permanent Rubine F6B or L6B) and permanent yellow DGR or DHG (Perma
nent Yellow DGR or DHG) can be used. In order to uniformly disperse the pigment in the ink, a dispersant is added. Suitable dispersants include CROSPERZ 25000 (CLO
SPERSE 25000) and Boehme Latex Canada Inc.
Filatex Canada Inc.).

After the ink has solidified, in step v)
By rubbing the anode surface with, for example, a soft rubber squeegee 11, any remaining non-coagulated ink is removed from the anode active surface to separate the coagulated ink from the non-coagulated ink and completely expose the colored coagulated ink. Preferably, the non-coagulated ink thus removed is collected and recycled to the supply means described above.

The reflection density of the dots of the colored coagulated ink can be changed by changing the voltage and / or pulse width of the pulse modulation signal applied to the cathode.

The printing medium S takes the form of a continuous web,
Passes a transfer position required for image formation. According to a preferred embodiment, as shown in FIG. 2, the apparatus 1 comprises an impression cylinder 13 which extends parallel to the cylindrical anode 3 and which presses against it to form a nip 14; The step b) of transferring the dot is performed by driving the impression cylinder 13 by the rotation of the anode 3 and guiding the web S to pass through the nip 14. Preferably, the impression cylinder is provided with a surrounding coating of a synthetic rubber material such as polyurethane having a Shore A hardness of about 95. A polyurethane coating having such a hardness further improves the transferability of the coagulated ink from the anode active surface to the substrate. The pressure applied between the anode and the impression cylinder is about 50-100 kg / cm ²
Is preferably within the range.

After the transfer step b), a cleaning of the anodic active surface is usually carried out in order to remove any remaining coagulated ink and oily substances from the anodic active surface. According to a preferred embodiment, the anode 3 is rotatable in a predetermined direction, and the remaining coagulated ink is removed from its active surface using an elongated rotating brush 151 extending parallel to the longitudinal axis of the anode. . The brush 151 comprises a plurality of radially extending bristles 152 made of horsehair and having tips in contact with the anode active surface, the direction of rotation of the anode 3 being such that the bristles 152 frictionally engage the anode active surface. The brush 151 is rotated in the opposite direction, and a jet of pressurized cleaning liquid is sprayed from both sides of the brush 151 onto the anode active surface by the high-pressure injector 153. In such embodiments, the anodic active surface is heated when the cleaning liquid is contacted with the cleaning liquid, and the ink is supplied from the anodic active surface to the ink by supplying ink onto the heated anodic surface. It is preferred that the anode active surface and the ink be maintained at a temperature of about 35-60 ° C so that migration occurs.

When printing a multicolor image, a plurality of printing units using mutually different hues of ink are arranged such that the cathode, the ink supply means, the current supply means and the transfer means constitute one printing unit. Along the path of
It is only necessary to form images of coagulated ink colored in various colors, and transfer the images by superimposing them on the printing medium at the respective transfer positions. Alternatively, an anode may be prepared for each printing unit, and a plurality of printing units may be arranged before and after (in tandem). Furthermore, each printing unit, each also including an anode, can be arranged around a single roller. The rollers are arranged to contact the dots of colored coagulated ink formed by each printing unit with the substrate, and the substrate in the form of a continuous web is partially wrapped around the rollers to provide individual After passing through the transfer position, various colored images are printed in a superimposed manner. Such an arrangement is disclosed in U.S. Pat. No. 4,895,629.

When printing a high-resolution multicolor image,
It is preferable to use an inextensible endless belt that moves at substantially the same speed as the anode. This endless belt has, on one side, an ink holding surface (for example, a porous surface) that holds the solidified ink dots detachably.
The dots of the solidified ink of different hues formed in each printing unit are successively transferred at each transfer position from the anode onto the ink holding surface by the first transfer means of each printing unit. The multicolor image on the endless belt is transferred and printed by the second transfer means by bringing the ink holding surface into contact with the printing medium. In this way, when transferring to the ink holding surface,
The alignment accuracy of images of different hues can be significantly improved, and as a result, the resolution of a multicolor image can be increased. The anode in this case is a cylindrical electrode having a longitudinal axis at the center and rotating at a substantially constant speed about this longitudinal axis, each printing unit being arranged around a cylindrical anode. Preferably, they are arranged. As the endless belt, a plastic belt whose surface is covered with a porous silica film can be preferably used.

Using such an apparatus with the anode of the present invention, a multicolor electrocoagulation printing method is preferably carried out, comprising the following steps: a) Ink present between the two electrodes using the anode and the cathode. C) forming a dot of the coagulated ink on the surface of the anode by electrolytically coagulating the ink by passing an electric current to the anode surface; b) transferring the dots of the coagulated ink to a non-stretchable endless belt; Steps a) and b) are repeated a plurality of times using electrocoagulation printing inks of different hues, so that dots of coagulation inks of different hues are sequentially superimposed and transferred onto the endless belt surface, and a multicolor image is formed on the endless belt surface. Forming; and d) transferring and printing the formed multicolor image on a printing medium.

More specifically, the multicolor electrocoagulation printing method preferably comprises the following steps: a1) moving at a substantially constant speed along a predetermined path, the continuous non-continuous layer defining the anode active surface. Providing an electrolytically inactive anode having a mobilized surface; a2) a colloidal composition comprising an electrolytically coagulable polymer, a dispersing medium, a soluble electrolyte and a colorant on the anode active surface. Forming a large number of dots of a colored coagulation ink representing the desired image by electrocoagulation of said electrolytically coagulable polymer present in an electrocoagulation printing ink comprising a dispersion; Contacting the non-extensible endless belt having an ink holding surface on one side thereof for detachably holding the dots of the colored and coagulated ink with the anode active surface. Causing the transfer of dots of colored coagulated ink from the anode active surface onto the ink retaining surface of the belt, thereby printing an image on the ink retaining surface; c) a predetermined location along the path Determine a number of printing stages, each of which uses a different colorant, thereby producing several different colored images of coagulated ink, wherein at each transfer position said colored image is:
Steps a2) and b) so that they are superimposed to obtain a multicolor image and are transferred onto the ink holding surface.
D) repeating the multicolor image from the ink-retaining surface onto a substrate, thereby printing the multicolor image on the substrate. Contacting the body with the ink retaining surface of the belt.

FIG. 3 shows a preferred embodiment of the multicolor electrocoagulation printing apparatus of the present invention. This device 2 comprises, as anodes according to the invention, a central cylinder-shaped anode 3 in the form of a rotating cylinder and four identical printing units 20 (20A, 20A) arranged around the cylinder-shaped anode 3.
20B, 20C, 20D). Of the printing units 20, the first printing unit 20 located on the left in the drawing
A is for yellow printing, the second printing unit 20B is for crimson (magenta) printing, and the third printing unit 20C is for printing.
Is the fourth printing unit 2 for blue-green (cyan) printing.
0D is provided for black printing. FIG.
As shown in FIG. 5, each printing unit includes a cathode 5, an ink supply unit 9, a current supply unit (not shown), a first transfer unit 131, and the like.

In a preferred embodiment, the device 2 comprises at least two printing units, each comprising a pair of impression cylinders (first transfer means) 131 arranged diametrically opposite one another. . By having two such pairs of impression cylinders arranged around the anode 3 at opposite positions, the forces exerted by each impression cylinder cancel each other out, so that the deflection of the anode is prevented.

The non-stretchable endless belt 17 moves at substantially the same speed as the anode, and has an ink holding surface 171 on one side thereof for detachably holding the dots of the colored coagulated ink. The endless belt 17 is brought into contact with the anode 3 by the impression cylinder 131, and the dots of the coagulated ink are transferred from the anode 3 to the ink holding surface 171.

Preferably, the ink comprises water as a dispersion medium and the dots of the coagulated ink of different hues are applied in step c) above.
And d). Thereby, the transfer of the multicolor image in the step d) is performed substantially completely. As shown in FIG. 3, a wetting unit 19 having a plurality of injection nozzles 191 can be used.

According to another preferred embodiment, the substrate S is in the form of a continuous web and is covered in step d) by a support roller 135 and a pressure roller (not shown) extending parallel to the support roller. The printed body S is carried. The pressure roller is pressed against the support roller 135 to form a nip through which the endless belt 17 passes. Support roller 13
5 and the pressure roller are driven by the movement of the endless belt 17, and together with a pair of guide rollers 137, the web S
Through the nip between the pressure roller and the porous surface (ink holding surface) 171 of the endless belt, and the multicolor image 200 is printed on the web S. here,
Support roller 135, pressure roller and guide roller 13
Reference numeral 7 integrally forms a second transfer unit. The endless belt 17 having the porous surface on which the multicolor image is formed moves along a path extending in a plane intersecting the longitudinal axis of the anode 3 located at the right corner in the drawing, and forms the web S and the porous material. Preferably, the surface 171 comes into contact. If the longitudinal axis of the anode 3 extends vertically, the endless belt 17 is guided to move along a horizontal path, with its porous surface 171 facing downward, and the support roller 135 The pressure roller is
It is located in a plane that extends perpendicular to the horizontal path.

After step d), the colloid holding surface 171 of the belt 17 is preferably cleaned to remove any remaining coagulated ink therefrom. According to a preferred embodiment, any remaining coagulated ink is transferred to the belt 1
7, at least one elongated rotatable brush 211 and at least one support roller 2 extending parallel to the brush and arranged on the other side of the belt.
13 is removed from the ink holding surface 171 of the belt 17. The brush 211 and the support roller 213 have a rotating shaft arranged in a plane extending orthogonally to the belt, and the brush 211 is made of horse hair and has a number of tips having a contact with the ink holding surface 171. Bristles 212 extending in the radial direction.
While supporting the belt 17 with the support roller 213, the brush 211 is rotated in a direction opposite to the moving direction of the belt 17 so that the ink holding surface 171 and the bristles 212 frictionally engage with each other. Sprays a jet of pressurized cleaning liquid onto the ink retaining surface, and also removes the cleaning liquid from the ink retaining surface along with the removed coagulated ink.

Various changes and modifications can be made to the preferred embodiments described above without departing from the technical spirit of the present invention, and all of them are included in the scope of the present invention.

[0046]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention. In addition,
Hereinafter, “% by weight” is simply described as “%”.

(1) Electrocoagulation printing ink Black ink was prepared using the following raw materials.

Anionic acrylamide polymer 8.8% (Mitsui Cytec Co., Ltd .; Accostength 86) Carbon black pigment 8.8% (Cabot Co .; Carbon Black Monarch 120) Anionic dispersant aqueous solution (active ingredient about 42%) 75% (Boehme Filexate Canada; Closperse 2500) Potassium chloride 8.8% EDTA disodium dihydrate 0.03% Preservative and fungicide 0.1% (Gray Products; Parmetol K-50) Ionized water 72.72% Total 100%

(2) Alloy for anode Anodes of Examples and Comparative Examples were produced using alloys having the compositions shown in Table 1. The alloy (CX-131) of Example 1 and the alloy (CF-3M) of Comparative Example were subjected to post-treatment after casting (heat treatment at 1120 ° C. and quenching in water) to obtain an alloy (CX-131) of Example 2. In 132), no post-processing was performed.
Table 1 also shows the obtained Brinell hardness.

[0050]

[Table 1]

(3) Electrocoagulation Printing Using an electrocoagulation printing apparatus shown in FIG. 1 of the type described in US Pat. No. 5,693,206, electrocoagulation printing was performed using the anodes of Examples and Comparative Examples, respectively. went. Oleic acid was used as the anode coating agent. The ink and the cleaning agent for cleaning the anode were heated to 40 ° C., the anode was kept at 40 ° C., and printing was performed for 5 hours a day. During this time, when the liquid level of the electrocoagulated printing ink in the ink supply device was lowered, the ink was added to keep the liquid level constant. After one day of printing, the presence or absence of wear or dents on the anode surface and the quality of the obtained printed matter were visually determined.

As a result, when the anode of the comparative example was used, 7
After a day, wear and dents of the anode were confirmed. On the other hand, in the anode of the example, slight wear and dents were confirmed only after 21 days. Further, the printed matter obtained in the examples showed excellent quality without density unevenness and no background. Instead of black ink, copper phthalocyanine indigo pigment (BASF; Heliogen Blue)
D7072), indigo ink, azo red pigment (Clariant; Permanent Rubin F6)
When the same examination was performed using the red ink using B), similar results were obtained regardless of the type of ink.

As described above, the anode of the present invention has good passivation film formation, has little mechanical wear and dents, can be used continuously for a long time, and has good cleaning properties after printing. It has been found that the printing is excellent, and that the printing using the ink is excellent in the electrocoagulability of the ink, the background is less generated, and a high-quality printed matter is obtained.

[0054]

As described above, according to the present invention,
It is possible to provide an anode which has sufficient hardness to sufficiently withstand washing without causing abrasion or depression, has excellent washing properties, and does not hinder the formation of a passivation film. This anode can be used for a long time because of its high durability, and has a long life as an anode. Using this anode, it is not necessary to frequently interrupt printing for polishing the anode surface, and a high-quality printed matter free of background can be provided with high productivity.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing an electrocoagulation printing apparatus according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing one of the printing units.

FIG. 3 is a plan view schematically showing a multicolor electrocoagulation printing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrocoagulation printing apparatus 2 Multicolor electrocoagulation printing apparatus 3 Anode 5 Cathode 9 Ink supply means 13 Transfer means 17 Endless belt 20 Printing unit S Printed object

Claims (10)

[Claims] 1. Cr: 20% by weight or more, Ni: 5 to 15%
% By weight, Si: 1-2% by weight, Mn: 0.9-1.5% by weight, C: 0.1-0.3% by weight, and the balance is composed of Fe and an Fe alloy consisting of unavoidable impurities. Anode for electrocoagulation printing. 2. The Fe alloy contains 25 to 28% by weight of Cr, 8 to 11% by weight of Ni, 1 to 2% by weight of Si,
n: 0.9 to 1.5% by weight, C: 0.1 to 0.2% by weight
The anode for electrocoagulation printing according to claim 1, wherein the balance comprises Fe and unavoidable impurities. 3. The method according to claim 1, wherein the Fe alloy is 1110 to 1
The anode for electrocoagulation printing according to claim 1 or 2, which is a cast alloy obtained by heat treatment at 130 ° C and subsequently quenching in water. 4. The anode for electrocoagulation printing according to claim 3, wherein the Fe alloy has an austenite-ferrite structure. 5. An electrocoagulation printing method comprising the following steps: a) an electrocoagulation printing ink using the anode and the cathode according to claim 1 and present between the anode and the cathode. Passing an electric current through the electrocoagulating printing ink to electrolytically coagulate the electrocoagulating printing ink to form a dot of the coagulating ink representing a desired image on the surface of the anode; and b) transferring the dot of the coagulating ink to a printing medium. The step of printing an image. 6. A multicolor electrocoagulation printing method comprising the following steps: a) electrocoagulation between the anode and the cathode, using the anode and the cathode according to claim 1. Passing a current through the printing ink to electrolytically solidify the electrocoagulated printing ink to form solidified ink dots representing a desired image on the anode surface; b) endlessly extending the solidified ink dots to a non-stretchable belt C) repeating the steps a) and b) a plurality of times using electrocoagulation printing inks of different hues to transfer dots of coagulation inks of different hues sequentially on the endless belt surface Forming a multicolor image on the surface of the endless belt; and d) transferring the multicolor image to print on a printing medium. 7. An electrocoagulation printing apparatus having the following configuration:
An anode and a cathode according to any one of claims 1 to 4; an ink supply means for supplying an electrocoagulated printing ink between the anode and the cathode; Energizing means for forming dots of the coagulated ink representing the image on the anode surface; and transfer means for transferring the dots of the coagulated ink from the surface of the anode to a printing medium to print an image. 8. The method according to claim 1, wherein the cathode, the ink supply means, the power supply means, and the transfer means are arranged to form one printing unit, and the coagulation inks of different hues are formed using electrocoagulation printing inks of different hues. The electrocoagulation printing apparatus according to claim 7, further comprising a plurality of the printing units that form dots, wherein a multicolor image is formed by superimposing and transferring the dots of the coagulation inks having different hues onto a printing medium. 9. The printing unit, wherein the anode is a cylindrical electrode having a longitudinal axis and rotates at a substantially constant speed about the longitudinal axis.
9. A method according to claim 8, wherein said step is arranged around said cylindrical anode.
An electrocoagulation printing apparatus as described in the above. 10. A multicolor electrocoagulation printing apparatus having the following constitution: an anode according to any one of claims 1 to 4; a non-stretchable endless belt; An ink supply means for supplying an electrocoagulated printing ink of a different hue to each other, and an energization for electrolytically coagulating the electrocoagulated printing ink to form dots of a coagulated ink representing a desired image on the surface of the anode. Means,
A plurality of printing units including first transfer means for transferring the dots of the coagulated ink from the surface of the anode to the surface of the endless belt; and the dots of the coagulated ink having different hues are superimposedly transferred by the plurality of printing units. Second transfer means for transferring the multicolor image formed on the surface of the endless belt to a printing medium for printing.