JPH04276482A - Image recording apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention uses ink whose adhesion changes depending on the polarity of the applied voltage, and uses porous insulation between the inking member, which is one electrode, and the plate, which is the other electrode. The present invention relates to an image recording apparatus that applies a voltage through a sheet, causes ink to adhere in a pattern onto the plate, and transfers the ink onto a recording medium.

0002

[Prior Art] Lithographic printing, letterpress printing, gravure printing, etc. are used in printing technology, but they require complicated steps to create plates and require dampening water to pattern the ink. It was extremely troublesome to handle. In addition, the adhesion of ink is easily affected by temperature and humidity,
Lacks environmental stability. For this reason, there are many difficulties in applying conventional printing techniques to recording peripheral devices such as computers.

On the other hand, printers using various recording methods, such as laser beam printers, inkjet printers, thermal transfer printers, wire dot printers, and daisy foil printers, are known as recording peripheral devices for computers and the like. However, these methods have the disadvantage that they are not suitable for the large-volume printing achieved by the above-mentioned printing techniques in terms of cost and the like.

[0004] In order to solve the drawbacks of these printers, when a voltage is applied to the ink through a pair of electrodes, the adhesive ink no longer adheres to the electrodes, or the non-adhesive ink adheres to the electrodes. Utilizing the property that the ink becomes The applicant has developed an image recording device that uses gas generated by electrolysis to change the adhesion of ink according to the pattern of the electrodes.
(See Publication No. 8).

However, these image recording devices
In order to increase the definition of the ink image, the gap between the plate and the inking member, which is a counter electrode, is made very narrow, so there is a drawback that leakage occurs between the plate and the inking member. there were. In order to prevent the occurrence of this leak, attempts have been made to adhere a porous insulating sheet 11 to the surface of an ink carrying roll 1, which is an inking member, as shown in FIG. Note that many of the parts in FIG. 4 are common to the embodiments described later, and therefore will not be described here.

[0006]

[Problems to be Solved by the Invention] In the conventional image recording device described above, gas is generated on the surface of the inking member by electrolysis of the ink, and when operated for a long time, this gas accumulates between the ink member and the porous insulating sheet. Therefore, there are disadvantages in that the porous insulating sheet is wrinkled and the ink image is disturbed, and the electrical resistance between the inking member and the plate is increased, making it necessary to increase the voltage applied.

An object of the present invention is to provide an image recording apparatus in which gas generated by energization does not accumulate between the inking member and the porous insulating sheet.

[0008]

[Means for Solving the Problems] The image recording device of the present invention has a structure in which the porous insulating sheet partially contacts the inking member within a certain range including the point where the porous insulating sheet contacts the plate. have

[0009]

[Operation] Since the structure is such that the porous insulating sheet partially contacts the inking member within a certain range including the point where the porous insulating sheet contacts the plate, there is a gap between the inking member and the porous insulating sheet. The generated gas is released into the surroundings as the inking member moves.

0010

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view of an image recording apparatus showing a first embodiment of the present invention.

Ink carrying roll 1 which is an inking member
metal materials such as aluminum, copper, stainless steel,
It is composed of a conductive rubber member made of a rubber material such as silicone rubber with carbon black and metal powder dispersed therein. A conveying roll 13 is provided that rotates in the direction of arrow A in parallel with the ink carrying roll 1. A belt-shaped porous insulating sheet 11 is stretched between an ink carrying roll 1 and a conveying roll 13 that rotate in the direction of arrow A'. Ink carrying roll 1
A plate 4 mounted on a plate cylinder 3 rotating in the direction of arrow B is in contact with a porous insulating sheet 11 interposed therebetween. A coating roll 9 rotating in the direction of arrow E is brought into contact with the conveyance roll 13 via the porous insulating sheet 11, so that the ink 2 can be supplied onto the porous insulating sheet 11 from the ink reservoir 10 on the coating roll 9. has been done. As the porous insulating sheet 11, for example, a porous body with continuous pores is preferably used. Porous bodies with open pores include, for example, sponges, filtering materials (Bel Eata (manufactured by Kanebo Co., Ltd.), etc.), abrasive materials, water absorbing materials, water supply materials, wiping materials (Berkulin (manufactured by Kanebo Co., Ltd.), etc.), nonwoven fabrics, Fabrics made of materials such as cheesecloth, cotton, acetate, polyester, and nylon;
Glass filters, ceramic filters, etc. are preferred. However, if the surface is rough, the surface shape of the porous insulating sheet 11 will tend to appear as a striped pattern in the ink adhered to the image-like pattern on the plate 4, so the diameter of the continuous pores will be determined by the ionic conductivity. It is preferable to keep it as small as possible within the range that can be maintained. Porous polyolefin films are known as such materials. For example, Exepol E.
BSP (manufactured by Mitsubishi Kasei Corporation), Hipore (manufactured by Asahi Kasei Corporation), Cellpore (manufactured by Sekisui Chemical Co., Ltd.), etc. are used. Further, in order to improve the osmotic pressure of the ink, electrolyte solution, etc. and improve the ionic conductivity, it is preferable to use a hydrophilic treated material for the porous insulating sheet 11. Ink carrying roll 1 via porous insulating sheet 11
The plate 4 on the plate cylinder 3 rotating in the direction of arrow B comes into contact with the ink 2 on the surface of the plate 4, and the ink 2 is transferred to the image area of the plate 4 to form an ink image. As the version 4, a known version can be used. For example, a plate for offset printing, a plate for gravure printing, a letterpress, etc. can be used. Further, the plate 4 is composed of a conductive part and an insulating part, and for example, by applying a voltage between the plate 4 and the ink carrying roll 1, the ink does not adhere to the conductive part of the plate 4, and the ink adheres only to the insulating part. You can do as you like. Further, a roll may be further interposed between the plate 4 and the ink carrying roll 1 to form a uniform ink layer, or the rolls may be used as a pair of conductive members to apply a voltage. The blank cylinder 5, which is an intermediate transfer member, rotates in the direction of arrow C while being in pressure contact with the plate 4, and transfers the ink image on the plate 4 to the blank cylinder 5. The impression cylinder 6 rotates in the direction of arrow D while being in pressure contact with the blank cylinder 5, and moves in the direction of arrow F between it and the blank cylinder 5.
Recording object 7 (paper, cloth, metal sheet, etc.) passing in the direction
The ink image on the blank cylinder 5 is transferred thereon. Recorded object 7
An image corresponding to the ink image is formed thereon.

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

A voltage is applied between the ink carrying roll 1 and the plate 4 by a power source 15, with the plate cylinder 3 side serving as a cathode and the ink carrying roll 1 side serving as an anode. The plate 4 side may be used as an anode, and the ink carrying roll 1 side may be used as a cathode. Specifically, the voltage from the power source 15 is preferably applied between the rotation axes of the plate cylinder 3 and the ink carrying roll 1, respectively. The thickness of the layer of ink 2 formed on the surface of the ink carrying roll 1 depends on the size of the gap between the ink carrying roll 1 and the coating roll 9, the fluidity or viscosity of the ink 2, and the ink carrying roll 1.
Surface material or roughness, or ink carrying roll 1
Although it varies depending on the rotational speed of the ink carrier roll 1, the ink transfer position where the ink carrying roll 1 faces the plate 4 on the plate cylinder 3 is approximately 0.001 to 100 mm, particularly 0.001 to 1 mm.
Preferably, it is 0 mm. The layer thickness of this ink 2 is 0
．． If it is less than 0.001 mm, it will be difficult to form a uniform ink layer on the ink carrying roll 1. On the other hand, if the ink layer thickness exceeds 100 mm, the ink 2
It becomes difficult to convey the ink carrying roll 1.
It becomes difficult to conduct electricity between the plate 4 and the plate 4. If the ink 2 contains water (water-soluble ink, emulsion ink), it can be changed from adhesive to non-adhesive by voltage application and can be used in the image recording apparatus of the present invention. The plate 4 has a desired insulating pattern made of an insulating material on a conductive base material such as metal. As the material for the conductive base material, aluminum, copper, stainless steel, platinum, gold, chromium, nickel, phosphorous copper, carbon, etc., conductive polymers, or various polymers in which metal fillers are dispersed are used. Insulating pattern materials include thermal transfer recording materials (mainly wax and resin), electrophotographic toner,
Vinyl polymers and natural or synthetic polymers are used.

Further, as the plate 4, a plate having an insulating film on which an image-like conductive pattern is formed by discharge breakdown on a base material made of a conductive material can also be used. 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.

By applying voltage from the power supply 15 between the plate 4 and the ink carrying roll 1 in this manner, 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 to be applied on the plate 4. Ink 2 is applied in a pattern to form an ink image. Practically speaking, the voltage of the power supply 15 is preferably a DC voltage of 3 to 100 V, particularly 5 to 80 V. Image quality can be further sharpened by further applying a high frequency (10 Hz to 100 kHz) AC bias voltage (10 V to 100 V). It can be done.

Next, the operation of this embodiment will be explained.

A porous insulating sheet 1 is stretched between a transport roll 13 rotating in the direction of arrow A and an ink carrying roll 1.
1, the ink 2 from the ink reservoir 10 is applied to a uniform thickness by a coating roll 9 rotating in the direction of arrow E. Next, a power supply 15 is provided between the plate 4 and the ink carrying roll 1.
When a voltage is applied, the ink 2 is deposited in a pattern on the plate 4 mounted on the plate cylinder 3 which rotates in the direction of arrow B while contacting the ink carrying roll 1 through the porous insulating sheet 11. The ink image formed on this plate 4 is
The ink is transferred to the blank cylinder 5 rotating in the direction of arrow C, and recorded as an ink image 8 on the recording medium 7 that moves in the direction of arrow F between the blank cylinder 5 and the impression cylinder 6 rotating in the direction of arrow D. . At this time, since the porous insulating sheet 11 is not in contact with half of the outer circumferential surface of the ink carrying roll 1, the gas generated on the outer circumferential surface of the ink carrying roll 1 is transferred between the ink carrying roll 1 and the porous insulating sheet 11. will not be accumulated between.

As a modification of this embodiment, the coating roll 9 shown in FIG. 1 may be in contact with the ink carrying roll 1 instead of the configuration in which it is brought into contact with the transport roll 13 side. Further, the ink carrying roll 1 and the conveying roll 13 do not have to be arranged vertically.

Next, the mechanism by which ink changes from adhesive to non-adhesive by voltage application will be explained.

[0021] When electricity is applied by applying a voltage, the ink is electrolyzed to generate gas, and this gas prevents the ink from adhering to the electrodes. 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 5 Ω·cm or less. Volume resistance is 105 Ω・cm
If the voltage exceeds 100%, the amount of current flowing decreases, or a high voltage is required to prevent the amount of current flowing. In addition, the transfer of ink to the plate is as follows for the part of the ink layer to which voltage is applied.
Almost the entire thickness (referred to as bulk movement) is transferred.

[0022] If the ink is a liquid such as water or alcohol, its cohesive force is weak and suitable adhesiveness cannot be obtained. This ink is preferably such that, for example, when a 2 mm thick ink is applied to a vertically erected platinum-plated stainless steel plate, the ink is substantially retained on the platinum-plated stainless steel plate. . In addition, the ink is sandwiched between two platinum-plated stainless steel plates to a thickness of 2 m.
m, and when two platinum-plated stainless steel plates are separated from each other with no voltage applied, it is preferable that ink adheres to both plates to the same extent. The viscosity of the ink is 101 to 1010 poise, especially 104 to 1010 poise at a shear rate of 10 rad/s and a temperature of 25°C.
108 poise is preferred.

[0023] The ink that employs the above-mentioned mechanism is basically composed of inorganic or organic fine particles and a liquid dispersion medium. The fine particles of ink improve the ink cutting and improve the resolution of the image. Ink is a colloidal sol, an amorphous solid, and non-Newtonian in fluidity.

In order to change the adhesion of the ink by applying a voltage, fine particles are contained in the ink. A fine particle dispersion is formed by kneading in the above-mentioned liquid dispersion medium, for example, in a homogenizer, a colloid mill, or an ultrasonic disperser. Such particles include metal (Au
, Ag, Cu, etc.) particles, sulfide (zinc sulfide ZnS,
Antimony sulfide Sb2S3, potassium sulfide K2S,
Calcium sulfide CaS, germanium sulfide GeS, cobalt sulfide CoS, tin sulfide SnS, iron sulfide FeS
, copper sulfide Cu2S, manganese sulfide MnS, molybdenum sulfide Mo2S3, etc.) particles, silicic acid (orthosilicic acid H
4SiO4, metasilicic acid H2SiO3, mesodisilicic acid H
2Si2O5, mesotrisilicate H2Si3O3, mesotetrasilicic acid H6Si4O11, etc.) particles, polyamide resin particles, polyamideimide resin particles, iron hydroxide particles, aluminum hydroxide particles, fluorinated mica particles, polyethylene particles, montmorillonite particles, fluororesins, etc. can be used. Further, polymer particles containing various charge control agents used as toners for electrophotography can also be used.

The above-mentioned fine particles have an average particle diameter of 10
Fine particles of 0 μm or less, preferably 0.1 μm to 20 μm, especially 10 μm or less, can be used, and such fine particles are contained in the ink in an amount of 1 part by weight or more, preferably 3 parts by weight to 100 parts by weight of the ink. It can be contained in an amount of 90 parts by weight, particularly preferably 5 to 60 parts by weight. Liquid dispersion media used in ink include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol (weight average molecular weight, approximately 10
0-1000), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl carbitol,
Ethyl carbitol, butyl carbitol, ethyl carbitol acetate, diethyl carbitol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, glycerin, triethanolamine,
Formamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N-methylacetamide, ethylene carbonate, acetamide, succinonitrile, dimethylsulfoxide, sulfolane, furfuryl alcohol,
N,N-dimethylformamide, 2-ethoxyethanol, hexamethylphosphoric triamide (hexamethylphosphoric triamide), 2-nitropropane, nitroethane, γ-butyrolactone, propylene carbonate,
One or a mixture of two of 1,2,6-hexanetriol, dipropylene glycol, hexylene glycol and the like can be used. The liquid dispersion medium is 40 to 95 parts by weight, particularly 60 to 95 parts by weight, based on 100 parts by weight of the ink.
It is preferable to contain 85 parts by weight.

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 to 90 parts by weight, based on 100 parts by weight of the ink material. It can be contained in an amount of 50 parts by weight, particularly 1 to 20 parts by weight. Such polymers include plant-based polymers such as guar gum, locust bean gum, gum arabic, taragant, carrageenan, vectin, 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; polyvinyl alcohol, polyvinylpyrrolidone,
Vinyl polymers such as polyvinyl methyl ether, carboxyvinyl polymer, sodium polyacrylate; other polyethylene glycol, ethylene oxide, propylene oxide block copolymer, alkyd resin, phenol resin, epoxy resin, amino alkyd resin, polyester resin, polyurethane resin , acrylic resin, polyamide resin, polyamideimide resin, polyesterimide resin,
Synthetic polymers such as silicone resins can be used alone or in combination of two or more. It is also possible to use greases such as silicone grease and liquid polymers such as polybdenum.

Since the change in ink adhesion is caused by the generation of gas due to electrolysis, water, water,
A solvent such as methanol, ethanol, glycerin, ethylene glycol or propylene glycol, or a solvent in which an electrolyte such as potassium iodide or lithium borofluoride is dissolved is preferably used. The contents of the liquid dispersion medium and fine particles are the same as those described above. In particular, it is preferable to use water or a liquid containing water as the liquid dispersion medium because hydrogen gas 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, particularly 5 parts by weight or more, based on 100 parts by weight of the ink. In the case of ink that generates gas through electrolysis, the fine particles contained in the ink include, in addition to those listed above, silica, fluorocarbon, titanium oxide, carbon black, fluorocarbon, and the like. In a preferred embodiment of the ink, considering the viscoelastic properties of the ink, it is preferable to use swellable fine particles capable of retaining the above-mentioned liquid dispersion medium as all or part of the fine particles in the ink. Examples of such swellable fine particles include Na-montmorillonite, Ca-montmorillonite, 3-octahedral synthetic smectite, Na-hectorite, Li-hectrite, Na-
Taeniolite, Na-tetrasilicic mica and Li-
Examples include fluorinated mica such as taeniolite, synthetic mica, and silica. The above-mentioned fluorinated mica can be represented by the following general formula (1). General formula (1) W1 ~1/3 (X, Y)2.5 ~3 (Z4 O
10) In the F2 formula, W is Na or Li, X and Y are Mg
2+, Fe2+, Ni2+, Mn2+, Al3
+, 6-coordinate ions such as Fe3+, Li+, Z is A
l3+, Si4+, Ge4+, Fe3+, B3
+ represents a cation with a coordination number of 4, such as + or a combination thereof (Al3+/Si4+).

[0028] The average particle diameter of the swellable fine particles is 75 μm or less in a dry state, more preferably 0.8 to 15 μm, especially 8 μm.
m or less is preferable.

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

[0030] In order to obtain such an ink, for example, a liquid dispersion medium and fine particles may be mixed by a conventional method.

FIG. 2 is a schematic sectional view of an image recording apparatus showing a second embodiment of the present invention, and FIG. 3 is a sectional view taken along the line GG' in FIG.

The porous insulating sheet 11 has a cylindrical shape with both ends circularly reinforced by being wrapped around the outer periphery of the frame 12b, which is a reinforcing member. The inner peripheral portion of the frame 12b is slidably fitted. A notch is formed at a rotationally symmetrical position on the outer periphery of the support 12a, through which the rotation axis of the ink carrying roll 1 and the rotation axis of the transport roll 13 pass, and the respective rotation axes pass through this cutout. frame 1
2b is provided with a stepped portion 12c as shown in FIG. 3, forming an internal gear. A gear 1a and a gear 1b are formed at the ends of the ink carrying roll 1 and the conveyance roll 13, respectively, and mesh with an internal gear formed on the stepped portion 12c.

As shown in FIG. 2, as the ink carrying roll 1 and the conveying roll 13 rotate, the frame 12b
The cylindrical porous insulating sheet 11 stretched over the
The same operation as in the first embodiment is performed, and the gas generated on the ink carrying roll 1 is not accumulated in this embodiment as well. In this embodiment, the rotation transmitting means is a gear as described above, but it is not limited to this, and it may be constructed of a member with a high coefficient of friction and brought into contact with the gear. Note that no matter how the structure is configured, the ink carrying roll 1 and the conveying roll 1
3 must be in contact with the porous insulating sheet 11, respectively.

In the first and second embodiments, the inking member and the plate were formed into rolls, but if the plate is a planar plate, a porous insulating sheet is stretched between the outer frame and the inking member and the plate. When the inking member and the plate come into contact with each other, it may be inserted laterally between the two, or a porous insulating sheet may be placed between the inking member and the plate so that they do not come into contact with each other. At this time, the inking member and the plate may be placed close to each other so as to sandwich the porous insulating sheet between them. <Prototype Example 1> An ink was manufactured as follows.

LiB was added to a mixed solvent consisting of 15 g of water and 49.4 g of glycol solvent TE-100 (manufactured by Asahi Denka).
60 g of F4 and 8.2 g of polyvinylpyrrolidone
Dissolved at °C. This includes colloidal silica, Aerosil #200 (manufactured by Nippon Aerosil Co., Ltd.), and carbon black.
11.8 g of Mogel L (manufactured by Cabot) was mixed and kneaded using a three-roll mill to obtain a black amorphous ink. When the volume resistivity of the obtained ink was measured, it was found to be 1×
It was 103Ω·cm. When printing was carried out using this ink using a device similar to that shown in FIG. 4, in which each member was configured as shown below, up to about 10 sheets could be printed without any leakage occurring between the plate 4 and the ink carrying roll 1. Good images with high resolution were obtained. Gas accumulates between the ink carrying roll 1 and the porous insulating sheet 11, and the porous insulating sheet 1
1 had wrinkles.

Plate cylinder 3: A pattern is created using vinyl resin on a 30 μm thick stainless steel plate, and an 80 m long plate made of silicone rubber and carbon black is created using conductive double-sided tape.
m diameter conductive silicone rubber roll (volume resistance 2 x 100
Ω・cm).

Ink carrying roll 1: 35 mm diameter, platinum-plated stainless steel roll Porous insulating sheet 11: 23 μm thick, porous polyolefin, Excelpol EBSP/BX-4, hydrophilic treated product (manufactured by Mitsubishi Kasei Corporation) Coating roll 9 ...Silicone rubber roll cylinder 5
...NBR rubber roll impression cylinder 6...Stainless steel roll The porous insulating sheet 11 on the ink-carrying roll 1 was adhered to both ends of the ink-carrying roll 1 and the joining part of the sheet with double-sided tape (not shown). <Prototype Example 2> Printing was performed using the same ink as in Prototype Example 1 and under the same conditions using the apparatus shown in FIG. 1. In FIG. 1, the conveyance roll 13 is a silicone rubber roll, and the other members are the same as in the first prototype.

Ink is uniformly applied onto the belt made of the porous insulating sheet 11 by the coating roll 9, and the plate cylinder 3 is rotated while applying a DC voltage of 40 V with the plate 4 as the cathode and the ink carrying roll 1 as the anode. Speed 100mm/s
When the plate was rotated using an ec, ink adhered to the pattern on the plate 4, and this ink was sequentially transferred from the blank cylinder 5 to the paper to obtain an image. When 20 sheets were continuously printed under these conditions, good images were obtained on all of them. There was no accumulation of gas between the ink carrying roll 1 and the porous insulating sheet 11, and no wrinkles or bubbles were generated in the porous insulating sheet 11. <Prototype Example 3> Using the same ink as in Prototype Example 1, printing was performed using an apparatus having the configuration shown in FIG. In the apparatus shown in Fig. 2, the drum 12... made of stainless steel (frame 12 with a diameter of 90 mm).
b, and a thread-wound support 12a having a central axis with a diameter of 20 mm); a conveyance roll 13...a silicone rubber roll (diameter 35 mm); and the same components as in Prototype Example 1 were used for the other members. When the plate cylinder 3 was rotated at a linear speed of 100 mm/sec and a voltage of 40 V was applied using the plate 4 as a cathode and the ink carrying roll 1 as an anode, ink selectively adhered to the pattern on the plate 4. By sequentially transferring this ink from the printing cylinder 5 to the paper, a good image was obtained, and when 20 sheets were continuously printed, there was no deterioration in image quality at all. No gas was accumulated between the ink carrying roll 1 and the porous insulating sheet 11, and no wrinkles or bubbles were generated in the porous insulating sheet 11.

[0039]

As explained above, the present invention has a structure in which the porous insulating sheet partially contacts the inking member within a certain range including the point where the porous insulating sheet contacts the plate. Even if continuous operation is performed, gas generated by electrolysis of ink will not accumulate between the surface of the inking member and the porous insulating sheet, so wrinkles and air bubbles on the porous insulating sheet will not be the cause. This has the effect that there is no need to increase the voltage required for energization because image disturbance does not occur and the electrical resistance between the inking member and the plate does not increase.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an image recording apparatus showing a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of an image recording apparatus showing a second embodiment of the invention.

FIG. 3 is a cross-sectional view taken along the line GG' of the apparatus shown in FIG. 2;

FIG. 4 is a schematic cross-sectional view of a conventional image recording device.

[Explanation of symbols]

1 Ink carrying roll 2 Ink 3 Plate cylinder 4th edition 5 Blanc body 6 Impression cylinder 7 Recorded object 8 Ink image 9 Coating roll 10 Ink reservoir 11 Porous insulation sheet 12 Drum 13 Conveyance roll 14 Conductive double-sided tape 15 Power supply

Claims (5)

[Claims] Claim 1: Using ink whose adhesion changes depending on the polarity of the applied voltage, a voltage is applied between an inking member as one electrode and a plate as the other electrode via a porous insulating sheet. In an image recording apparatus that applies a voltage to deposit ink in a pattern on the plate and transfer it to a recording medium, the porous insulating sheet An image recording apparatus characterized in that the inking member has a structure in which the inking member partially contacts the inking member. 2. In the structure, the inking member is a roll, the porous insulating sheet is an endless belt, a conveying roll is provided parallel to the inking member and close to the coating roll, and the inking member is a roll. 2. The image recording apparatus according to claim 1, wherein a porous insulating sheet is stretched between the inking member and the conveyance roll so as to come into contact with the printing plate and the coating roll. 3. In the structure, the inking member is a roll, the porous insulating sheet has a cylindrical shape with circular reinforcement at both ends, and a conveyance roll is provided in parallel with the inking member, 2. The image recording apparatus according to claim 1, wherein the porous insulating sheet is in contact with the printing plate, and an inner surface is in contact with the inking member and the conveyance roll. 4. The image recording apparatus according to claim 1, wherein the porous insulating sheet is hydrophilic. 5. The image recording apparatus according to claim 1, wherein a voltage is applied using the plate as a cathode and the inking member as an anode.