JPH11105418A - Method for forming/recording image and image forming material used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming/recording an image with a high degree of freedom by which it is possible to form a high-quality image with the use of a fine particle coloring material of pigment and even at an applied voltage with a small potential difference to be generated in compliance with a photoimage signal and further, in a highly safe and simple manner. SOLUTION: In this method for forming/recording an image, an image retaining member with an electrode and an image retaining face is provided in a container for retaining a liquid, and an aqueous dispersion containing an electrodeposition material comprising a polymer to be chemically dissolved or deposited and sedimented according to the change of a pH value and a fine particle coloring material, is prepared in a container for a device combined with an opposite electrode. Further, an electric current or an electric field is supplied to the image retaining member and the opposite electrode in compliance with an image pattern, and thereby, the electrodeposition material containing the coloring material is deposited and sedimented to form the image. In this case, the electrodeposition material has a hydrophobic group and a hydrophilic group in a molecule and the number of the hydrophobic groups of the polymer is within the range of 40-80%, in proportion, of the total number of the hydrophilic groups and the hydrophobic groups. The 50% or higher of the hydrophilic group part has such a characteristic that it can reversibly change from the hydrophilic group to the hydrophobic group due to a change in the pH value. Besides, the 50% or higher of the hydrophilic group part contains a copolymer whose acid value is 30-400.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming and recording method for forming an image by electrochemically insolubilizing an image forming material by applying a current to a dispersion of an aqueous fine particle colorant.

[0002]

2. Description of the Related Art There are many office image recording techniques using a liquid image forming material. For example, silver salt technology, ink jet technology, electrophotographic technology, and the like.

[0003] Printing technology using silver halide is disclosed in Hatsumi Tanemura et al., "High-quality color copy system using silver halide photography", Japan.
an Hardcopy '89 Research Proceedings P2
29. Printing technology using electrophotographic technology of liquid development,
E. FIG. B. Caruthers, et al. , "Mod
eling of Liquid Toner Ele
critical Characteristics "
Proceedingsof IS & T 10th I
nt @ l. Congress on Advances
in Non-Impact Printing T
technologies P204 ($ 94). Printing technology using inkjet technology is Minoru Usui's new method MAC
There are many technical announcements such as "Development of H" Japan Hardcopy '96.

In the conventional printing technique, there is no problem in image quality and image fastness in the printing technique using silver salt.
The printing process involving a chemical reaction involves the use and disposal of chemicals such as chemically active metal compounds, which has caused problems in office adaptation. In inkjet printing technology, it is difficult to obtain high resolution due to the problem of nozzle diameter and printing reliability, and the image forming material is generally an aqueous dye,
There is a problem in image fastness, safety, and printability on plain paper. Electrophotographic technology has no problem in image quality, printability on plain paper, and image robustness comparable to printing, but consumes a large amount of energy in the fixing section, and the complicated printing process increases the machine size and safety. -Problems have occurred in reliability.

As a prior art similar to the image forming method of the present invention, a technique using an electrodeposition liquid in which a coloring material is dispersed in an insulating liquid to generate an electric double layer is disclosed in Japanese Patent Laid-Open No. 7-1817.
No. 50, Japanese Patent Publication No. 7-54407, a technique using an electrodeposition printing technique in which an insulating pattern is provided on a conductive substrate to form a printing plate is disclosed in Japanese Patent Application Laid-Open No. 4-9902. Japanese Patent Application Laid-Open No. 6-293125 discloses an electrodeposition offset printing method and a printing plate.

[0006] By the way, characteristics required for printing technology used in offices are that a high quality image of 600 DPI or more / multi-value gradation can be obtained, printing on plain paper is possible,
There are demands for image robustness comparable to printing, high security of printed matter and printing machines, little waste, low running cost, and the like. On the other hand, in the prior art, there are various disadvantages as described above, and the technology described in each of the above patents utilizing electrodeposition is also
The technology that can fully satisfy them has not been completed.

High image quality (1000 DPI level resolution /
When good color reproduction / multi-valued gradation is achieved, the image structure is preferably 2 μm or less, more preferably 1 μm or less in view of the relationship between color reproduction range and image sharpness. Become. As a result, it is necessary that the average shape diameter of the image forming material, which is an element for providing an image structure, is a size of submicron or less. However, if the average shape diameter of the image forming material is 5 microns or less, there is a problem in fluidity, so that the powder type image forming material is practically difficult to use. On the other hand, liquid image forming materials are considered to be quite effective in this regard. Also, in the image forming process of an image on the order of several microns, it is technically difficult to control the pixel shape with high accuracy in a minute area of the image forming material particles, and a dye-based aqueous solution of a molecular order, which is a minute minimum particle, is formed on the electrodeposition material. Is considered to be one of the very effective methods from the viewpoint of a highly accurate color material control method.

The electrophotographic technique using an insulating liquid developer disclosed in the above-mentioned patents such as Japanese Patent Application Laid-Open No. 7-181750 is capable of high resolution because the shape diameter of the image forming material is on the order of submicron, and printing is possible. The suitability of plain paper is also high. However, since a hydrocarbon-based solvent is used as a developing solution, safety due to solvent vapor is considered to be a major problem, and in some cases, its use is severely restricted by countries.

The electrodeposition printing technique disclosed in Japanese Patent Application Laid-Open No. 4-9902 and the like, in which an insulating pattern is provided on a conductive substrate and used as a printing plate, employs an insulative resist in advance by a photolithography process. Since the process is complicated, such as creating a non-image part, it is difficult to change the image pattern every time to print.In addition, the precision of the equipment is large and the number of steps is large. It can be used only when it is installed in a well-equipped factory to perform printing work. Further, the history of the image forming process is likely to remain on the substrate, and the reproducibility of fine image recording is low. In addition, since the image portion is concave, the image portion also has a low particle adhesion selectivity due to the particle migration phenomenon, and a large amount of the liquid component of the image forming material in the image portion is likely to remain. The image forming material in the image area is liable to cause flow and cohesive failure, and it is difficult to obtain high image quality. Further, these are all technologies for producing a printing plate corresponding to a fine pattern, and do not directly record an image on a recording medium.

As described above, in the conventional image forming method, a printing technique which is highly safe and can be performed by a simple apparatus and which satisfies the characteristics required for the printing technique used in the office is still realized. Did not.

[0011]

SUMMARY OF THE INVENTION High image quality (600 DPI)
/ Multi-valued gradation or more), it is preferable that the shape of the image forming material is 1 micron or less, and it is necessary to use a liquid image forming material which can contain a fine particle coloring material. Considering that it is installed in an office, it is necessary that the liquid used in the image forming material has high safety, and it is preferable to select water having no problem in safety. In addition, in the printing technology in the office, it is necessary to easily and inexpensively produce a small quantity of many kinds of prints, so that a printing process using a printing plate that cannot be reproduced is poor in adaptability. Therefore, every time printing is performed, an image signal is input to create image information, and the print output is a system in which the image-formed image forming material is transferred to various types of recording media, such as plain paper, that meet the various needs of the user and recorded. Is preferred in the market.

In addition, it is necessary to use a pigment-based coloring material in consideration of the image fastness, high optical density, and safety against being taken into the human body. In the printing process, energy consumption must be suppressed more than necessary.

The present invention has been made in view of the above-described characteristics, and an object of the present invention is to realize high image quality by using a pigment-based fine particle coloring material, and to produce a high quality image corresponding to an optical image signal. An image can be formed even by an applied voltage having a small potential difference between the image forming portion and the reference electrode, and is a highly safe and simple method, and a highly flexible image recording method and an image forming material which can be suitably used for the method. To provide.

[0014]

The main components of the image forming and recording method of the present invention are an aqueous dispersion containing a pigment-based coloring material and a specific electrodeposition material, a container thereof, and an electrode capable of generating an electrical image pattern. An image holding member and a counter electrode, and
A jig for immersing an image holding member or the like in a container into which an aqueous electrodeposition material dispersion liquid is injected, which is an auxiliary member, and fixing it at a predetermined position, and a control device for each of the above members. The image pattern formed on the image holding member by depositing and sedimenting the electrodeposition material by this apparatus can directly handle the image holding member as a document, and transfer and fix the image to another medium as a document. Can also handle.

That is, according to the image forming / recording method of the present invention, an image holding member having an electrode capable of supplying a current or an electric field at least in accordance with an image pattern and a surface capable of holding an image in a container capable of holding a liquid; An aqueous dispersion containing a fine particle colorant and an electrodeposition material made of a polymer that is chemically dissolved or precipitated / sedimented due to a change in pH is prepared in a container of a device having a counter electrode which is the other of the pair. Applying an electric current or an electric field to the image holding member and the counter electrode in accordance with an image pattern to change the pH of the dispersion in the vicinity of the image holding member, thereby depositing and sedimenting the electrodeposition material containing the fine particle colorant to form an image. Wherein the electrodeposition material comprising the polymer has both a hydrophobic group and a hydrophilic group in the molecule, and the number of hydrophobic groups in the polymer is 40% of the total number of the hydrophilic group and the hydrophobic group. % In the range of 80%, it has a property capable of reversibly changing the hydrophobic group from the hydrophilic groups over 50% by a change in pH of the hydrophilic group moiety, and an acid value of 30 to 400
Characterized by containing a copolymer represented by the formula:

The means for supplying a current or an electric field to the image holding member and the counter electrode has a mechanism for converting a light image signal into a current in response to a light image signal input. Means for generating a current corresponding to the optical image signal is preferable.

Further, in the polymer compound constituting the electrodeposition material, a hydrophilic group portion capable of reversibly changing from a hydrophilic group to a hydrophobic group by a change in the pH has a carboxyl group or an amino group. It is preferable to contain a styrene or α-methylstyrene unit from the viewpoints of sensitivity and image retention.

The image forming material of the present invention is used in the image forming and recording method, and comprises a fine particle coloring material and an electrodeposition material made of a polymer which is chemically dissolved or precipitated / precipitated by a change in pH. An aqueous dispersion containing the polymer, wherein the electrodeposition material comprising the polymer has both a hydrophobic group and a hydrophilic group in the molecule, and the number of the hydrophobic groups of the monomer units constituting the polymer is a ratio of the total number of the hydrophilic group and the hydrophobic group. 40% to 80% of the above, 50% or more of the hydrophilic group portion has the property of being able to reversibly change from a hydrophilic group to a hydrophobic group by a change in pH, and
It is characterized by containing a copolymer having an acid value of 30 to 400.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

According to the image forming and recording method of the present invention, an image holding member having an electrode capable of supplying at least a current or an electric field according to an image pattern and a flat member holding an image in a container capable of holding a liquid; An aqueous dispersion (hereinafter referred to as appropriate) containing a fine particle coloring material and an electrodeposition material made of a polymer which is chemically dissolved or precipitated / sedimented by a change in pH in the container of the other device having a counter electrode. , An aqueous colorant electrodeposition liquid or simply referred to as an electrodeposition liquid). First, the aqueous colorant electrodeposition liquid will be described.

The constituent materials of the aqueous colorant electrodeposition liquid are water-insoluble colorant particles, an aqueous electrodeposition material, water and an aqueous solvent as main components, and in addition, a wetting material, a water-soluble polymer material, an emulsion material, Additives such as latex materials, various solvents, surfactants, antiseptic / antifungal agents, and pH adjusters can be used as long as the effects of the present invention are not impaired.

The composition of the aqueous colorant electrodeposition liquid has a solid content of 1% by weight to 40% by weight, preferably 5% by weight to 19% by weight. When the solid content concentration is less than 1% by weight, there are problems that it is difficult to obtain dispersion stability of the coloring material component and it is difficult to easily obtain a sufficient optical density of an image.
When the solid content concentration is higher than 40% by weight, the liquid tends to be non-uniform at the time of electrodeposition, and the liquid exhibits thixotropy.

In the solid components of the electrodeposition liquid, the amount of the coloring material component is from 20% by weight to 80% by weight, preferably from 30% by weight to 50% by weight, based on the total solid components. If the value is lower than the above range, the gloss of the image becomes too high,
This may cause the optical density of the image to decrease. On the other hand, when the value is higher than the above range, the electrodeposition efficiency is reduced, and defects and defects are easily generated in the image layer formation, the fixing strength is lowered, and the color tone is problematic.

The conductivity of the electrodeposition solution is 10 ⁵ Ω · cm or less,
Preferably, it is in the range of 10 ³ Ω · cm to 1 Ω · cm.
If the value is higher than the above range, the electrodeposition voltage is increased, the bubbling phenomenon of the electrode is activated, and the electrodeposition phenomenon becomes unstable, and the film quality of the formed image tends to vary. On the other hand, if it is too low, the current of the image signal is spread, and the resolution of the image is reduced.

The viscosity of the electrodeposition solution is from 1 cps to 1000 cp.
s is good, more preferably from 10 cps to 200
cps range. If the value is lower than the above range, the liquid tends to be scattered due to insufficient viscosity of the liquid, and if the value is higher than the above range, the operation load becomes large in the transportability and agitation of the electrodeposited liquid, and the complex viscosity characteristic is increased. , It causes problems such as a decrease in efficiency.

In setting the initial value of the pH of the electrodeposition solution, when applying the electrodeposition method in which the electrodeposition material contained in the electrodeposition solution is anodic deposition, a pH value of 1 ± 2 from the deposition start pH point is used. Value, more preferably 1 ± 1.5.
In the case of the electrodeposition method in which the electrodeposition material is cathode deposition, the deposition start p
The pH of the electrodeposition solution is set to a value of -1 ± 2 from the point H, more preferably, to a value of -1 ± 1.5.
By setting to such an initial value, the deposition and sedimentation of the electrodeposition material are performed sharply, and high electrodeposition film formation efficiency is maintained. If the pH is set so that precipitation is easier than the precipitation start pH point outside the above range, the dispersion stability of the electrodeposition liquid cannot be obtained, and there are inconveniences such as precipitation of color material particles in the non-image area and variation in the amount of electrodeposition. . If the deposition start pH is out of the above range, the efficiency of electrodeposition film formation is low, causing an increase in electrodeposition potential and a problem in the film properties of the formed film.

The electrodeposition material which plays an important role in the image forming recording material of the present invention in connection with the preferable properties of the electrodeposition solution is a dispersion of the colorant particles in an aqueous liquid which is a main component of the electrodeposition solution. Function to improve electrodeability, electrodeposition adsorption phenomenon, that is, a function to form an electrodeposited film (image) by rapid precipitation and sedimentation due to electrochemical changes in the environment, and a function to impart water resistance to the electrodeposited film (image) Plays an important role. Therefore, the electrodeposition material needs to have a molecular structure having both a group that is hydrophilic and easily ion dissociated in an aqueous liquid (hydrophilic group) and a hydrophobic group that dislikes water.

Here, the image forming action of the present invention will be described. The ion-dissociated hydrophilic group in the polymer constituting the electrodeposition material is changed by the change in pH of the electrodeposition liquid on the surface of the image holding member due to energization. Ion dissociation is suppressed and a hydrophobic function is developed, thereby rendering the entire structure of the electrodeposited material itself hydrophobic, rendering the electrodeposited material containing the coloring material insoluble in an aqueous liquid and retaining an image. An image is formed by precipitation and sedimentation on the member surface. This phenomenon is thought to be due to the fact that the molecular chains that had spread in the liquid of the electrodeposition material were shrunk due to the change in pH, agglomeration occurred with the color material particles, and the phenomenon of precipitation of an image containing the color material particles was observed. Can be

As a guide for selecting a polymer compound to be used for the electrodeposition material, the solubility characteristics of the polymer with a change in pH are shown in the graph of FIG. FIG. 1 is a graph showing the relationship between the dissolution characteristics of a polymer used for various electrodeposition materials and the pH of a solution. Good balance between hydrophilic and hydrophobic groups in the polymer,
Further, in a material having a hydrophilic group which can be changed to a hydrophobic group depending on conditions, as shown in graph A (shown by a solid line), a certain p
Precipitation occurs sharply at the boundary of the H value, while in the case of a material having a large number of hydrophilic groups, the solubility is good regardless of the pH value as shown in a graph B (shown by a broken line). Also, when there are many hydrophobic groups,
It becomes insoluble irrespective of the pH value like the material of the graph C (indicated by the two-dot broken line). Further, even if the balance between the hydrophilic group and the hydrophobic group is good, a material that does not have a hydrophilic group that can be converted to a hydrophobic group or has a small proportion thereof is dissolved as shown in a graph D (indicated by a dashed line). Even if the properties change, the change in dissolution / precipitation is insufficient for image formation. These properties also vary with the relationship between the material and the solvent used. In the present invention, it is preferable that precipitation occurs rapidly at a certain pH value as shown in graph A.

The electrodeposition material has a constitution containing a thermoplastic resin component, and must exhibit sufficient solubility in the adjusted aqueous liquid. As shown in the graph A of FIG. 1, the change in the pH value of the electrodeposition solution in which the electrodeposition material is dissolved causes a change in the liquid property in which a supernatant is generated from the dissolved state of the electrodeposition material to cause precipitation, thereby causing a precipitation. It is required to occur within one. In order to obtain more preferable properties, the pH range is preferably within 0.5. With the characteristics in this range, it is possible to instantaneously deposit an image even when the pH changes sharply due to energization, and to increase the cohesive force of the deposited image and reduce the rate of re-dissolution in the electrodeposition solution. Making it possible. Thereby, the water resistance of the image is also obtained. If the pH range of the liquid property change that causes precipitation from the dissolved state to the change in the pH value of the electrodeposition liquid is larger than 1, the printing speed is reduced to obtain a sufficient image structure and the image lacks water resistance. For example, there may be a problem in printing characteristics.

For example, when a carboxyl group is used as a hydrophilic group, it is necessary to set the pH at the precipitation start point and the dissolution start point in an acidic range. Is set to 5.0 or more and 6.9 or less, preferably 5.5 or more and 6.5 or less. It suffices that the pH of the recording material in at least a portion of the recording material that is in contact with the surface of the image holding member is set to the above value.
Actually, the starting point of precipitation and the starting point of dissolution of the recording material can be confirmed visually using a buffer solution of the recording material and a commercially available pH meter.

The function of the electrodeposited material according to the present invention is required to have the above-mentioned action characteristics. Therefore, it is necessary to have the structure and characteristics as described below.

The electrodeposition material is composed of a copolymer containing a monomer unit having a hydrophilic group which dissociates ions and a minimum monomer unit having a hydrophobic group which promotes insolubilization in an aqueous electrodeposition solution. The ratio of the total number of the hydrophilic groups to the hydrophobic groups is from 40% to 80
%, More preferably 55% to 70%
The electrodepositing composition having the above-mentioned range is particularly preferred because it has a high electrodeposition deposition efficiency, exhibits an electrodeposition characteristic of forming a film at a low electrodeposition potential, and has stable liquid properties of the electrodeposition liquid. The number of the hydrophilic groups and the number of the hydrophobic groups can be calculated, for example, in the case of a vinyl polymer or the like, based on the charged ratio of the monomers during the polymer polymerization reaction.

When the number of hydrophobic groups in the monomer units of the copolymer constituting the electrodeposition material is less than 40% of the total number of hydrophilic groups and hydrophobic groups, the water resistance of the electrodeposition film formed at the time of electrodeposition and the film If the strength is insufficient and the number of hydrophobic groups is 80% or more of the total number of the hydrophilic groups and the hydrophobic groups, the solubility in the aqueous liquid becomes insufficient, and the electrodeposition liquid becomes turbid or precipitates of the electrodeposition material are formed. However, there are problems such as the occurrence of such a problem and an increase in the viscosity of the electrodeposition solution, which are not preferable.

FIG. 2 is a graph showing the relationship between the water resistance of the electrodeposited film on which an image is formed by precipitation and sedimentation, and the ratio of these hydrophobic groups and the total number of hydrophilic groups and hydrophobic groups. A line a parallel to the horizontal axis of this graph is a water-resistant region required to hold an image, and a line b is a region having a good water resistance. When the number of hydrophobic groups increases more than the line c parallel to the vertical axis, the solubility of the polymer material decreases and the properties of the solution become unstable. When the number of lines exceeds d, the material becomes insoluble and measurement becomes impossible.

The monomer unit containing a hydrophilic group used in the electrodeposition material includes methacrylic acid, acrylic acid, hydroxyethyl methacrylate, acrylamide, maleic anhydride, trimellitic anhydride, phthalic anhydride, hemi-mellitic acid, succinic acid , Adipic acid, propiolic acid, propionic acid, fumaric acid, itaconic acid, and the like, and derivatives thereof. In particular, methacrylic acid and acrylic acid have a large effect / effect on the electrodeposition phenomenon, and are useful hydrophilic monomer structural units having high electrodeposition efficiency due to pH change and high hydrophilicity efficiency.

Although various polymers can be used in the present invention, preferred are a vinyl polymer obtained from a vinyl monomer, and a polyester resin obtained by polycondensation of a polyol and a polycarboxylic acid. The ratio of the hydrophilic group to the hydrophobic group in the polymer is as described above. In the case of the vinyl polymer, the number of the hydrophobic groups of the monomer units constituting the vinyl polymer is the total number of the hydrophilic group / the hydrophilic group and the hydrophobic group. By charging monomers so as to be in the range of 40% to 80% of the ratio of the above, a polymer having almost the same ratio can be obtained in the obtained polymer. In the case of a polyester resin, a polymer having a hydroxyl group or a carboxyl group at a terminal is obtained by condensation polymerization of a hydroxyl group of a polyol and a carboxyl group of a polycarboxylic acid.In this case, the charged amount of the polycarboxylic acid is smaller than that of the polyol. By increasing the amount, a polymer having a carboxylic acid at the terminal can be obtained. In this case, the number of the hydrophobic groups and the number of the hydrophilic groups of the monomer units used at the time of charging are different from those of the obtained polymer.
In the present invention, the ratio of the hydrophilic group to the hydrophobic group in the obtained polymer is important.

Further, at least 50%, more preferably at least 75%, of the hydrophilic group portion of the monomer unit of the copolymer constituting the electrodeposition material can be reversibly changed from a hydrophilic group to a hydrophobic group by a change in pH. It is preferably a hydrophilic group portion of the unit. This hydrophilic group is ion dissociated in an aqueous solvent and exhibits hydrophilicity, but is a functional group that suppresses ion dissociation due to a change in the pH of the electrodeposition solution and exhibits a hydrophobic function.

Specific examples of the ionic dissociating hydrophilic group include a carboxyl group, an amino group, a sulfonic acid group, a quaternary ammonium group, and a sulfate group.
Among them, those having a carboxyl group or an amino group as a hydrophilic group have a high image deposition efficiency in the electrodeposition phenomenon and exhibit characteristics of forming a highly robust electrodeposited film. These groups have a high efficiency of reversibly changing from a hydrophilic group to a hydrophobic group by a change in pH, and are suitable for application to the present invention.

More specifically, when the image pattern generating portion is more anodically than the reference electrode, the electrodeposited material has a carboxyl group, and the carboxyl group, which is the hydrophilic group in the aqueous liquid, dissociates ions to form an anionic group. At the same time, a part of the electrodeposited material is bonded, adhered or associated with the surface of the colorant particles, and the acid value of the electrodeposited material is preferably in the range of 60 to 300. Preferably, the value is in the range from 90 to 150. When the image pattern generating portion is more cathodic than the reference electrode, the electrodeposited material has an amino group, and the amino group which is a hydrophilic group portion of the electrodeposited material in an aqueous liquid becomes a cation group by ion dissociation, At the same time, it is preferable that a part of the electrodeposition material is bonded, adhered or associated with the surface of the coloring material particles.

The electrodeposited material containing a hydrophilic group capable of changing its structure shows a so-called hysteresis curve as shown by a solid line in FIG. In other words, the re-dissolution is not performed abruptly in response to a change in the pH value, and is maintained in a precipitated state for a certain period of time. This characteristic is ideal from the viewpoint of image forming properties and stability of the formed image. . A material having such re-dissolution characteristics in addition to the precipitation characteristics shown by the graph A shown in FIG. 1 above, that is, having a large Δt in the graph of FIG. 3 is preferable. Δt is a measure of the water resistance of the deposited electrodeposition film (image). The polymer compound represented by the broken line in FIG. 3 has the same structure as the copolymer represented by the solid line, but has a molecular weight of 4,
Less than 000, easily re-dissolved due to low water resistance, and the material showing such re-dissolution characteristics has good image formability, but the stability of the formed image is slightly inferior. A device must be devised for holding and transporting to the transfer process section to the recording medium.

To form such a hysteresis curve,
Not only the properties of the polymer compound but also the properties related to the deposition of the material are involved. That is, since the deposited electrodeposition material is aggregated, and the solution is extruded from the aggregate of the aggregated material, the amount of water contained in the image formed by the aggregated material and the fine particle coloring material taken therein is adjusted, For example, when the formed image is transferred to a transfer unit for transfer, the application of voltage is stopped, and even if the pH value of the solution changes again, the re-dissolution of the electrodeposited material is not immediately started. It is also known that the stability of an image is improved.

The hydrophobic group in the structure of the electrodeposition material has a strong affinity for an organic pigment used as a coloring material, has an adsorption ability to the pigment, and gives a good pigment dispersing function. Also,
A printing function for instantaneously depositing an image is imparted to the hydrophilic desorption of the hydrophilic group portion of the electrodeposition material due to a change in pH due to the application of a voltage. In particular, when the ratio of the total number of the hydrophilic groups to the hydrophobic groups in the monomer unit of the electrodeposition material is in the range of 40% to 80%, the effect of reducing the electrodeposition potential for forming a strong film is large, and Therefore, it is an indispensable condition for completing a low-potential printing process using a photoelectromotive force due to light input.

The monomer units containing a hydrophobic group used in the electrodeposition material include an alkyl group, styrene, α-methylstyrene, α-ethylstyrene, methyl methacrylate,
Butyl methacrylate, acrylonitrile, vinyl acetate,
Ethyl acrylate, butyl acrylate, lauryl methacrylate, and the like and derivatives thereof are used. In particular, styrene and α-methylstyrene have high hydrophobicization efficiency, high electrodeposition deposition efficiency, and high controllability during polymerization during production, and are useful hydrophobic monomer structural units.

The acid value of the electrodeposited material of the type which deposits an image on the positive electrode is preferably in the range of 60 to 300 from the viewpoint that good electrodeposition characteristics can be obtained. The acid value of the electrodeposition material is 60
In the following cases, the solubility in the aqueous liquid becomes insufficient, the solid content concentration of the electrodeposition liquid cannot be increased to an appropriate value, the liquid becomes turbid, a precipitate is formed, and the liquid viscosity increases. Occurs. When the acid value of the electrodeposition material is 300 or more, the formed film has low water resistance and the electrodeposition efficiency with respect to the amount of electricity supplied is low.

As described above, the electrodeposition material according to the present invention is mainly composed of a polymer compound obtained by copolymerizing a molecule containing a hydrophilic group and a hydrophobic group in the above ratio. The type of group is not limited to one. Further, the copolymer may be any of random, block, and graft copolymers.

The average molecular weight of the copolymer is 4,000 from the viewpoint of the properties of the electrodeposited film and the adhesive strength of the film.
To 30,000 can obtain a good electrodeposited film (deposited image). From the viewpoint of more preferable film properties and film adhesive strength, those having an average molecular weight of 9,000 to 20,000 are suitable. If the average molecular weight is lower than 4,000, the deposited electrodeposited film is non-uniform and has low water resistance, so that the formed image has low robustness and may not be retained image-wise and may be powdered. On the other hand, if the average molecular weight is higher than 30,000, the solubility in the aqueous liquid becomes insufficient, so that the solid concentration of the electrodeposition liquid cannot be increased to an appropriate value, or the liquid becomes cloudy or precipitates are formed. In addition, the viscosity of the liquid increases, which causes a problem.

The preferred characteristics of the electrodeposited material are as described above, but the electrodeposited material constituting the image forming material used in the image forming / recording method of the present invention has all of the above characteristics in a well-balanced manner. Is preferred.

As the colorant particles used in the image forming and recording method of the present invention, those having an average particle diameter in the range of 0.01 μm to 1.2 μm, preferably 0.02 μm to 0.3 μm are suitable. I have. When the average particle diameter is less than the above range, the light-shielding property of the image layer is reduced, so that the optical image density is apt to be reduced, the gloss is generated more than necessary in the image, and the problem is easily caused in safety. Further, when the average particle diameter exceeds the above range, the dispersion state of the electrodeposition liquid of the color material particles becomes poor and precipitates are generated, or a problem occurs in the uniformity of the image layer containing the color material particles or the light shielding property by the particles is generated. Is likely to occur, making it impossible to cope with a transmissive image, or causing an image to be unnecessarily matted. Especially the average particle size range 0.2
In the range of 0 μm or less, the dispersion stability is excellent as an aqueous dispersion material, and the color transparency is high.

As the coloring material particles, dyes and pigments which are insoluble or low in water are suitable. Specifically, for example, carbon black, titanium oxide, zinc white, red iron oxide, alumina white, aluminum powder, Bronze powder,
Zinc oxide, barium sulfate, magnesium carbonate, ultramarine,
Inorganic pigments such as graphite, cobalt blue, navy blue, etc., toluidine red, permanent carmine FB, fast yellow G, disazo yellow AAA, disazo orange P
MP, lake red C, brilliant carmine 6B, phthalocyanine blue, indanthrone blue, quinacridone red, dioxazine violet, victoria viewer blue, alkali blue toner, aniline black, permanent red 2B, barium lithol red, quinacridone magenta, naphthol red HF4
B, organic pigments such as phthalocyanine green, benzimidazolone red, Victoria Blue 4R base, nigrosine, nigrosine base, C.I. I. Solven
t Yellow 19, C.I. I. Solvent
Orange 45, C.I. I. Solvent R
Oil-soluble dyes such as ed8 and the like, as well as disperse dyes, dyed lake pigments, and resin powders in which a dye is contained in a resin, may be mentioned as those which can obtain appropriate characteristics.

Examples of the aqueous solvent used with the electrodeposition material and the colorant particles include water, alcohols such as methanol, ethanol, butanol, and isopropyl alcohol; ketones such as acetone and methyl ethyl ketone; ethanolamine and dimethylamine. , And various amines such as triethanolamine, and acids such as acetic acid, sulfuric acid, phosphoric acid, oxalic acid, and phthalic acid can be used alone or in combination. Very useful in terms of safety, stability and cost.

It is preferable to mix a water-soluble solvent as a wetting agent in order to prevent deterioration of the electrodeposition solution due to evaporation of the aqueous solvent component. However, this water-soluble solvent has high hydrophilicity and has an azeotropic point with water. A liquid with a high boiling point and a low vapor pressure is preferred. The required properties are a highly polar solvent and a boiling point of 120 ° C.
Above, the saturated vapor pressure in the atmosphere is 100 mmHg or less, preferably, the boiling point is 150 ° C or more, and the vapor pressure in the atmosphere is 60 mmHg.
g or less is good. Outside the above range, the electrodeposition solution evaporates greatly, shortening the life of the electrodeposition solution or increasing the change in the properties of the solution, making it difficult to obtain stable electrodeposition characteristics. The composition ratio is preferably in the range of 0.5% to 70% by weight, and more preferably in the range of 5% to 30% by weight. Specific examples include ethylene glycol, diethylene glycol, polyethylene glycol, glycerin, diacetanol, methylcellosolve, ethylcellosolve, butylcellosolve, and ethylene glycol diacetate.

The addition of a polymer additive or an emulsion material provides stable film formation characteristics during electrodeposition, and is important for improving the film properties of the electrodeposited film, the robustness of the electrodeposited image, and controlling the electric resistance of the film. Show the effect. The amount of these added is preferably in the range of 0.2% by weight to 50% by weight, and more preferably in the range of 1% by weight to 15% by weight, as the concentration of solid content.

Examples of the polymer additive include gelatin, gum arabic, pectin, casein, starches, microcrystalline cellulose, alginate, polyvinyl alcohol, vinyl acetate copolymer, polyacrylic acid copolymer, and methylcellulose derivatives. This is shown as a representative example.

As emulsion materials, polyvinyl acetate emulsion, vinyl acetate copolymer emulsion,
Acrylic ester copolymer emulsions, synthetic rubber latex and the like are shown as typical examples.

In addition, an antiseptic / antifungal agent, a trace amount of a surfactant, a pH adjuster or a liquid viscosity adjuster may be added in some cases. In particular, in the present invention, since an aqueous liquid is used as the dispersion medium, the liquid is liable to be deteriorated due to propagation of microorganisms and generation of mold, and from the viewpoint of the stability of the liquid, an antiseptic / antifungal agent is added. Is preferred.

The preferred image forming conditions and the apparatus suitably used in the image forming / recording method of the present invention are described below.

The voltage difference applied between the electrode and the image holding member in the image forming (electrodeposition) step in the method of the present invention is as follows:
A DC power supply within ± 5 V is often used. However, in order to sharply reproduce one pixel at a time on an image, a short-time DC pulse and a signal input of the short pulse by a heavy pulse may be performed. The applied voltage difference is more preferably 3
Use a DC power supply within V. If film properties are more important, use a DC power supply within 2.5V. When a voltage difference of 5 V or more is applied, the generation of bubbles due to the electrolysis of the solution from the electrode surface in the liquid becomes severe, the electric field distribution on the electrode surface becomes uneven, and the film quality of the film itself becomes uneven, The film surface becomes uneven due to the defoaming phenomenon, and it becomes difficult to reproduce an image of a target fine pattern. Electrodeposition coating is a technique similar to the image forming process of the present invention. In general, in electrodeposition coating, an applied voltage of 100 V or more is applied to perform electrodeposition. This is because, when the applied voltage is low, the resistance of the electrodeposited film generated is high, and as the electrodeposited film formation proceeds, the electrodeposited film formation speed is greatly reduced and the required film thickness (generally 20 μm
Above), to avoid this, apply a high voltage to cause a vigorous bubbling phenomenon due to electrolysis, and use it to stir near the electrode surface and bring the electrode surface into contact with a new electrodeposition liquid. As a result, a film thickness necessary for electrodeposition coating is obtained.

The purpose of the present invention is to reproduce a high quality image, specifically, a fine image (40 μm) at a film thickness level of 2 μm or less.
(0 dpi or more) In order to reproduce the pattern, it is necessary to suppress the bubbling phenomenon due to the electrolysis of the electrodeposition solution, and if it occurs, it must be suppressed to a level that does not affect the reproduction of a fine image pattern. The applied voltage difference is a DC electric field of 5 V or less, preferably 3 V for printing finer images (800 dpi or more), and 2.5 V or less if image quality is more important. Also, the voltage applying means may use a three-electrode method in consideration of voltage stabilization. Further, since an image can be formed by applying a voltage having such a small voltage difference, a mechanism for converting an optical image signal into a current in response to an optical image signal input is provided in the image forming step of the present invention. It can be used as a means.

That is, the photovoltaic power is usually 1 V or less, for example,
0.6-0.7 for general purpose using silicon material
Although it is about V, considering that the bias voltage is about 1.5 V, it is understood that the image forming and recording method of the present invention can be suitably used for inputting an optical image signal.

In the case of optical writing, the structure of the image holding member is composed of at least a planar electrode layer and a photoconductive material layer, and a current flows on the surface of the image holding member in the light-irradiated portion to cause electrolytic adhesion of color material particles. It has a structure to do.

Next, an image recording apparatus which can be suitably used in the image recording method of the present invention will be described. FIG. 4 is a schematic view showing an image recording apparatus of the present invention used in a first embodiment described later. In the image recording apparatus, an image holding member 3 composed of a flat member having a work electrode capable of inputting an image signal from the back surface is placed in an electrodeposition liquid bath 1 filled with an aqueous color material liquid 1 for electrodeposition. A counter electrode 5 and a control electrode 6 using a salt bridge are also installed in the bath 1. The image holding member 3 is made of a laminated structure in which a transparent conductive layer of ITO is provided on a sheet glass substrate having a thickness of 4 mm and two organic photoconductor layers are formed thereon, and the ITO conductive layer is used as a work electrode, and an organic photoconductor is used. The surface of the layer is smooth without any steps. Each electrode is connected to a potentiostat power source 4, and a voltage is applied between the work electrode and the counter electrode 5 from the potentiostat power source 4 while inputting an image to the optical image input section on the back surface of the image holding member 3. The electrodeposited material therein is deposited together with the color material particles on the surface of the image holding member 3 to form an image. The image recorded here can be transferred and fixed to a transfer target such as plain paper or a plastic film, if desired, as described later.

The image recording method will be described in detail. FIG. 5 is a conceptual diagram showing an image recording phenomenon due to deposition of an electrodeposition material. When a voltage is applied from the DC power supply 8 to the pseudo current supply electrode 7 arranged imagewise on the image holding member 3, the pH of the electrodeposition liquid 1 near the electrode 7 changes, and the electrodeposition liquid 1 dissolves in the electrodeposition liquid 1.
The electrodeposited material 9 containing the dispersed coloring material particles is deposited on the surface of the image holding member 3, and the polymer compound containing the coloring material deposited imagewise adheres, and the image 10 is recorded. Also, in FIG.
The structure of the electrodeposited particles in the electrodeposition liquid is schematically shown. In the electrodeposition solution, the polymer compound 25 constituting the electrodeposition material is present near the surface so as to cover the coloring material particles 24, and it is presumed that a part thereof exists as free ions 26 of the electrodeposition material. .

Next, a process of transferring and fixing the image thus recorded on another recording medium will be described. FIG. 7A is a schematic diagram showing the above-described image recording process. The image 10 formed by the recording material deposited on the surface of the image holding member 3 is held. (B) is a schematic diagram showing an image transfer process. Plain paper 11 as a transfer object is laminated on the image holding member 3 taken out from the aqueous electrodeposition liquid 1, and is pressed by a transfer roller 12, more preferably, heated.
Pressure is applied to transfer and fix the image 10 on the plain paper 11.
(C) shows the image 10 transferred and fixed on the plain paper 11, and the recording of the image on the plain paper (transfer medium) 11 is completed in this way.

As the image holding member used in the image recording method of the present invention, one having high smoothness on the surface on which an image is formed and having no steps can obtain good printing characteristics, and can easily obtain good transfer characteristics. An important characteristic is that the surface energy is low from the viewpoint of preventing the image from remaining when different images are formed using the holding member.

More specifically, the surface roughness (Ra) of the surface of the image holding member is preferably in the range of 0.01 μm to 1.5 μm, and more preferably in the range of 0.06 μm to 0.5 μm. Transfer characteristics can be obtained. Also,
The critical surface tension of the surface of the image holding member is 35 dyne / c
m or less, more preferably from 20 dyne / cm to 29 d
Good transfer characteristics can be obtained when the amount is in the range of yne / cm 2.

From these viewpoints, it is necessary to form a low surface energy layer on the surface of the image holding member. Examples of the material include a fluorine resin and a fluorine rubber (FE).
P), a dimethylsiloxane-based resin, silicone rubber, a wax-based material, and the like, and a composite material obtained by mixing a conductive powder with these materials for the purpose of controlling the electric resistance of the layer itself is also used. .

As described above, the surface of the image holding member having a high surface smoothness and a low surface energy can obtain good printing characteristics. In particular, this characteristic becomes important when a repeated image holding member is used. Thereby, the physical cleaning property of the image on the image holding member surface is improved, and a printing cycle in which the history of the previously recorded image information does not always remain even if different image recording is performed every time can be constructed.

In the image forming step, in order to maintain the uniformity of the liquid property of the bath of the electrodeposition solution, it is preferable to perform stirring in the liquid bath to form a uniform image (electrodeposited film). Is preferred. However, stirring that is too strong may delay film formation or cause liquid scattering, so it is necessary to select suitable stirring conditions in consideration of the state of the liquid.

By controlling the liquid temperature, more uniform and good film properties can be obtained. Since this phenomenon itself is affected by the liquid temperature, when aiming to reproduce high-quality images,
In particular, it is necessary to install a highly accurate liquid temperature control system.

The image formed on the flat member surface of the image holding member in the image forming step can be transferred to another recording medium. In the image transfer step, the formed image (electrodeposited film) is transferred from the image holding member to a transfer medium such as plain paper using electrostatic force, pressure, adhesive force and the like.

In particular, in the image transfer step, the image transfer is carried out in a state in which an appropriate amount of the liquid component of the electrodeposition solution is contained at the time of film formation, so that the transferred image material exhibits viscous properties, However, viscous deformation of the image is caused only by the pressure, and the image can be transferred. This makes it possible to construct an image forming process in which the entire system is more compact and consumes no wasteful energy.

If the configuration of the image holding member is a belt shape, image recording, transfer to the object to be transferred, and fixing can be performed continuously, so that efficient image recording becomes possible.

In producing such a belt-shaped image holding member, a polyimide resin and its modified compound, a polyaramid resin and its modified compound,
Alternatively, a polymer such as a silicone resin and a modified compound thereof, or a material containing these as a main component may be used. When the image holding member is formed into a belt shape, the belt can be bent at an acute angle to efficiently remove the color material attached to the surface, and enhance the physical cleaning property of the image on the image holding member surface, Even if particle deposition recording of a different image is performed each time, it is possible to construct a printing cycle in which the history of previously recorded image information does not always remain.

FIG. 8 is a schematic diagram showing one embodiment of the system of the image recording apparatus according to the present invention. Since the image holding member 3 has a belt shape, the image 10 recorded by applying an optical signal in the aqueous color material liquid 1 is conveyed while being adhered to the surface of the belt-shaped image holding member 3, and is transferred at the transfer portion. The paper is transferred onto the paper 11 supplied from the paper roll 19 when passing through the gap between the pressurizing and heating rolls 12. The dye remaining on the image holding member 3 is removed by the cleaning brush 20 and accumulated in the cleaning waste tray 21. The image holding member 3 cleaned by the cleaning brush 20 is again used for image recording.

When the image holding member is continuously used in the form of a belt as described above, the color remaining on the surface of the flat member after the image forming step and the image transferring step is completed and before the image forming step is performed again. It is preferable to remove materials, electrodeposition materials, and the like. A known cleaning method such as a blade method, a fur brush method, an elastic roller method, a cleaning web method, and a liquid cleaning method can be applied as a method for removing the image forming material remaining on the surface of the flat member of the image holding member.

According to the image forming and recording method of the present invention, an image holding member for generating an electric current corresponding to an optical image signal is disposed in a liquid containing colorant particles in an aqueous system, and an electrodeposition is performed in accordance with the image current. A recording method for forming an image containing a group of ionic colorant particles by causing a phenomenon on an image holding member surface, and an image forming / recording method including a post-process of transferring the recorded image to a transfer medium. In particular, the image forming / recording method is characterized in that the transfer step is performed when the image adhered to the image holding member surface contains the liquid component of the electrodeposition solution. Can be formed,
Wide application range.

[0078]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

(Example 1) Styrene-acrylic acid copolymer
(Molecular weight: 13,000, hydrophobic group / hydrophilic group + hydrophobic group
Ratio: 65%, acid value: 150) 20% by weight alkaline water
90 parts by weight of solution, carbon black powder (average particle
(Diameter: 0.08 μm) 11 parts by weight, diethylene glycol
15 parts by weight, 7 parts by weight of isopropanol, distilled water
 15 parts by weight, mixing the above materials, propeller of medium strength
Stir for 1 hour to make carbon buccac powder sufficiently liquid
Wet to produce a crude dispersion. Next, this dispersion liquid is
High-intensity forced dispersion treatment for 6 minutes using a homogenizer
To prepare a dispersion stock solution. 60 parts by weight of distilled water,
Lycerin 10 parts by weight, fungicide (ICI Proxe
XL-2) 0.8 parts by weight of the mixed diluent
Dropping into this dispersion stock solution while stirring with a propeller, electrodeposition
A color material particle dispersion was completed. This solution is an aqueous solution of phosphoric acid
And adjusting the pH with an aqueous sodium hydroxide solution,
The pH was set to 7.9. The starting point of the color material particle precipitation of this liquid
pH was 6.2. And a complete supernatant precipitate
The resulting pH point was 5.7. Also, the conductivity of this liquid
Is 5 × 10 ^TwoΩ · cm.

Next, an image was recorded by applying this aqueous coloring material liquid to an image recording apparatus as shown in FIG. As shown in FIG. 4, the image recording apparatus is configured such that an image holding member 3 having a work electrode capable of inputting an image signal from the back side is placed on an electrodeposition bath 2 containing the electrodeposition solution 1, and the back side is outside the bath. Put it out,
Then, a counter electrode 5 and a control electrode 6 using a salt bridge were installed in the bath. This image holding member is made of a 3 mm-thick plate glass substrate provided with a transparent conductive layer of ITO on which a two-layer organic photoconductor layer is laminated. The ITO conductive layer is used as a work electrode, and the organic photoconductor layer is formed. Was smooth without any steps. Each electrode was connected to a potentiostat power supply.
Then, while inputting an image to the optical image input section on the back side of the image holding member, a 2.7 V D.V. C. Voltage was applied for 5 seconds.

Next, the image holding member on which the image formation was completed was taken out of the liquid, and it was confirmed that a high quality image having an optical image density of 1.43 was formed on the surface of the image holding member.

(Example 2) 2 of α-methylstyrene-methacrylic acid copolymer (molecular weight: 17,000, molar ratio of hydrophobic group / (hydrophilic group + hydrophobic group): 70%, acid value: 160)
120 parts by weight of a 0% by weight aqueous alkali solution, 20 parts by weight of carbon black powder (average particle diameter: 0.07 μm), 10 parts by weight of polyethylene glycol, 10 parts by weight of isopropanol, 20 parts by weight of distilled water, and the above materials were mixed. Strong propeller stirring was performed for 3 hours to sufficiently wet the carbon bulk powder into a liquid to prepare a coarse dispersion.
Next, this dispersion liquid was subjected to a dispersion treatment for 35 hours using a ball mill disperser to prepare a dispersion liquid. Distilled water 100
A mixture of 20 parts by weight of glycerin, 0.5 part by weight of a fungicide (Proxel XL-2, ICI) was added dropwise to the dispersion liquid while stirring with a propeller to disperse the colorant particles for electrodeposition. The liquid was completed. This solution was adjusted to pH 8.1 by adjusting the pH with a phosphoric acid aqueous solution and an ammonia aqueous solution. The pH of the liquid at the starting point of the precipitation of the coloring material particles was 6.3. The pH point at which complete precipitation of the supernatant was 5.9. The conductivity of the liquid was 2 × 10 ² Ω · cm ² .

Next, using the image recording apparatus shown in FIG.
An image holding member 3 with a work electrode to which an image signal can be input from the back side is placed in a liquid bath 2 containing the above-mentioned electrodeposition liquid such that the back side is outside the liquid bath. A control electrode 6 using a bridge was installed in the bath. The image holding member 3 is made of a 2 mm thick quartz substrate on which a transparent conductive layer of ITO is provided, on which a two-layer organic photoconductor layer is laminated, and the ITO conductive layer is used as a work electrode, and an organic photoconductor is used. The surface of the layer was smooth. Each electrode was connected to a potentiostat power supply. Then, the He- light emitted from the laser light source 22 to the optical image input section on the back surface of the image holding member is provided.
While inputting an image with the Ne laser beam 23, the potentiostat power supply 4 applies a 2.9 V D.E. between the work electrode and the counter electrode. C. A pulse voltage (pulse width 3 ms / pulse period 4 ms) was applied.

Next, the image holding member after the completion of the image formation was taken out of the liquid, and it was confirmed that a high quality image having an optical image density of 1.48 was formed on the surface of the image holding member.

Example 3 Styrene-α-methylstyrene
-Acrylic acid copolymer (molecular weight: 11,000, hydrophobic
Group / (hydrophilic group + hydrophobic group) molar ratio: 72%, acid value: 14
0) 150% by weight of 20% by weight aqueous alkali solution, lid
Russianin powder (average particle size: 0.2 μm) 10 weight
Parts, water-soluble acrylic resin 6 parts by weight, isopropanol
 10 parts by weight, mixing the above materials, medium strength propeller
Stir for 0.5 hours to sufficiently wet the pigment powder to liquid
This produced a crude dispersion. Next, this dispersion liquid is homogenized.
Perform dispersion for 10 minutes using a disperser and disperse
A stock solution was made. 100 parts by weight of distilled water, diethylene glycol
Recall 20 parts by weight, fungicide (ICI Proxe
XL-2) 0.5 parts by weight of the mixed diluent
Dropping into this dispersion stock solution while stirring with a propeller, electrodeposition
A color material particle dispersion was completed. This solution is an aqueous solution of phosphoric acid
And adjusting the pH with an aqueous solution of lithium hydroxide, p
H7.7 was set. P of the starting point of colorant particle precipitation of this liquid
H was 6.3. And a complete supernatant precipitate
The pH point was 5.9. The conductivity of this liquid is
9 × 10 ^TwoΩ · cm.

Next, using the apparatus shown in FIG. 10, the image holding member 3 capable of inputting a current image signal from the back side is placed in the electrodeposition bath 2 containing the electrodeposition solution, and the back side is outside the electrodeposition bath. The counter electrode 5 and the control electrode 6 using a salt bridge were set in the bath 2. The image holding member 3 was provided with a 5 mm-thick conductive layer in which current diffusion was suppressed, and the surface of the conductive layer in contact with the liquid was made smooth. Each electrode was connected to a control power supply. Then, 600 is input to the image input unit on the back side of the image holding member.
An image is input using a needle electrode image input print head 12 of DPI, and a voltage of 3.1 V between the needle electrode and the counter electrode is applied.
C. Pulse voltage (pulse width 2ms / pulse cycle 3ms)
Was applied in synchronization with the scanning speed of the print head 12.

Next, the image holding member after the completion of the image formation was taken out of the liquid, and it was confirmed that a high-quality image having a cyan optical image density of 1.53 was formed on the surface of the image holding member. Further, the voltage between the needle electrode and the counter electrode is set to 2.3 V D.E. C. It was confirmed that a high-quality image having a cyan optical image density of 1.15 was formed on the surface of the image holding member by printing with a pulse.

Example 4 A 20% by weight aqueous alkaline solution of a styrene-maleic anhydride copolymer (molecular weight: 8,000, hydrophobic group / (hydrophilic group + hydrophobic group) molar ratio: 62%, acid value: 190) 220 parts by weight, 20 parts by weight of carbon black powder (average particle diameter 0.07 μm), 10 parts by weight of polyethylene glycol, 3 parts by weight of water-soluble acrylic resin, 10 parts by weight of isopropanol, 50 parts by weight of distilled water , Medium intensity propeller stirring
After a period of time, the carbon bulk powder was sufficiently wetted with a liquid to prepare a coarse dispersion. Next, this dispersion liquid was subjected to a dispersion treatment for 24 hours using a ball mill disperser to prepare a dispersion stock solution. A diluent obtained by mixing 80 parts by weight of distilled water, 10 parts by weight of glycerin, 4 parts by weight of pyrrole, and 0.5 parts by weight of a fungicide (Proxel XL-2, ICI) was dropped into the dispersion without stirring with a propeller. Thus, a colorant particle dispersion for electrodeposition was completed. The pH of this solution is adjusted with a phosphoric acid aqueous solution and an aqueous ammonia solution to adjust the pH.
It was set to 7.8. P of the starting point of colorant particle precipitation of this liquid
H was 5.9. The pH point at which complete precipitation of the supernatant occurred was 5.4. The conductivity of the liquid was 1 × 10 ² Ω · cm.

Next, using an apparatus similar to that of Embodiment 1 shown in FIG. 4, an image holding member provided with a work electrode to which an image signal can be input from the back side is placed in an electrodeposition liquid bath containing the above electrodeposition liquid. At the same time, the back side was placed outside the electrodeposition liquid bath, and a counter electrode and a control electrode using a salt bridge were installed in the bath. The image holding member is made of a 2 mm thick quartz substrate provided with a transparent conductive layer of ITO on which a two-layer organic photoconductor layer is laminated, and the ITO conductive layer is used as a work electrode, and the organic photoconductor layer is formed. Had a smooth surface. Each electrode was connected to a potentiostat power supply. Then, while inputting an image to the optical image input section on the back surface of the image holding member with a He-Ne laser beam, a 2.2 V D.V. C. A voltage was applied.

Next, the image holding member on which the image formation was completed was taken out of the liquid, and it was confirmed that a high quality image having an optical image density of 1.26 was formed on the surface of the image holding member.

(Example 5) In the same manner as in Example 1, a dispersion for electrodeposition was prepared, and the image holding member having an image formed on the surface thereof was taken out of the electrodeposition liquid bath through an image forming step. Plain paper was placed on the surface of the flat member on which the image containing the coloring material particles was formed. A corona discharge of +6 KV was performed from above the paper, and a pair of rubber rollers were then pressed with a linear pressure of 500 g / cm.
, And pressurized and rotated and conveyed the plain paper and the image holding member. Immediately after the pressurization, the plain paper was peeled off from the image holding member, and a transferred image having an optical image density of 1.36 was obtained on plain paper.

Example 6 Styrene-acrylic acid ester-acrylic acid copolymer (molecular weight: 16,000, molar ratio of hydrophobic group / (hydrophilic group + hydrophobic group): 2.0, acid value: 18)
180 parts by weight of a 20% by weight alkaline aqueous solution of 0), carbon black powder (average particle size: 0.07 μm)
5 parts by weight, 15 parts by weight of glycerin, 7 parts by weight of isopropanol, 55 parts by weight of distilled water, and the above materials are mixed, and a medium-strength propeller is stirred for 1 hour to sufficiently wet the carbon black powder into a liquid to obtain a coarse dispersion. It was created.
Next, the dispersion liquid was subjected to a high-intensity forced dispersion treatment for 3 minutes using a homogenizer disperser to prepare a dispersion stock solution. 100 parts by weight of distilled water, aqueous solution of vinyl acetate emulsion 8
0 parts by weight, fungicide (Proxel XL-2, ICI)
0.6 parts by weight of the mixed diluent was dropped into this dispersion stock while stirring with a propeller to complete a colorant particle dispersion for electrodeposition. This solution was adjusted to pH 7.8 by adjusting the pH with a phosphoric acid aqueous solution and sodium hydroxide. The pH at the colorant particle deposition start point of this liquid was 5.9. The pH point at which complete supernatant precipitation occurs is 5.
It was 6. The conductivity of this liquid is 5 × 10 ² Ω · c
m.

Next, as shown in FIG. 4, the image holding member provided with the work electrode from which the image signal can be inputted from the back side is put into the electrodeposition bath containing the above electrodeposition solution, and the back side goes out of the bath. And a control electrode utilizing a salt bridge was installed in the bath. This image holding member is made of a laminated structure of a two-layer organic photoconductor layer on which a transparent conductive layer of ITO is provided on a 4 mm-thick soda lime glass substrate, and the ITO conductive layer is used as a work electrode, and an organic photoconductor is formed. The surface of the layer was smooth. Each electrode was connected to a potentiostat power supply. Then, while inputting an image to the optical image input unit on the back surface of the image holding member, a 2.6 V D.V. C. Voltage was applied for 9 seconds.

Next, the image holding member on which the image formation was completed was taken out of the liquid, and it was confirmed that a high quality image having an optical image density of 1.48 was formed on the surface of the image holding member.
Next, as a result of performing an eraser rub fixing test, the optical density change amount of this print sample was 0.2. on the other hand,
When the same fixing test was performed on the print sample of Example 1, the optical density change amount was 0.5. Thus, it was confirmed that the fixability was improved by the addition of the emulsion aqueous solution.

Example 7 A 20% by weight aqueous alkali solution of a styrene-acrylic acid copolymer (molecular weight: 13,000, hydrophobic group / (hydrophilic group + hydrophobic group) molar ratio: 68%, acid value: 150) 90 parts by weight, 11 parts by weight of carbon black powder (average particle size: 0.08 μm), 7 parts by weight of isopropanol, 15 parts by weight of distilled water, and the above materials were mixed and stirred with a medium-strength propeller for 1 hour to obtain a carbon powder. The powder was sufficiently wetted with a liquid to form a coarse dispersion. Next, the dispersion liquid was subjected to a high-intensity forced dispersion treatment for 3 minutes using a homogenizer disperser to prepare a dispersion stock solution. A diluent obtained by mixing 140 parts by weight of distilled water and 0.3 part by weight of a fungicide (Proxel XL-2, ICI) was dropped into the dispersion without stirring with a propeller, and a colorant particle dispersion for electrodeposition was added. Completed.

Next, the image holding member provided with the work electrode to which an image signal can be input from the back surface used in Example 1 shown in FIG. 4 was placed in an electrodeposition solution bath containing the above electrodeposition solution. It was placed outside the bath, and a counter electrode and a control electrode using a salt bridge were installed in the bath. Then, while inputting an image to the optical image input section on the back surface of the image holding member, a 2.5 V D.V. C. Voltage was applied for 7 seconds.

Next, the image holding member on which the image formation was completed was taken out of the liquid, and it was confirmed that a high quality image having an optical image density of 1.36 was formed on the surface of the image holding member.

Then, the electrodeposition recording apparatus containing the above-mentioned electrodeposition liquid of this embodiment and the same electrodeposition recording apparatus containing the electrodeposition liquid of Example 1 were left as they were for one week. as a result,
The liquid level of the electrodeposition recording apparatus of the present embodiment dropped by 25 mm, but the liquid level of the electrodeposition recording apparatus of Example 1 dropped by 9 mm. As a result, it was found that the addition of a wetting agent such as diethylene glycol and isopropanol was effective in preserving the liquid properties.

Example 8 The same electrodeposition solution as in Example 1 was completed in the same manner as in Example 1.

Next, by using the same apparatus as that of the embodiment 2 shown in FIG. 8, He-Ne is applied to the optical image input section on the back surface of the image holding member.
2.0 V between the work electrode and the counter electrode from a potentiostat power supply while inputting an image with laser light
D. C. Pulse voltage (pulse width 2 ms / pulse period 3
ms). In this example, an image was formed under the same conditions as in Example 2 while a propeller for stirring was placed in the electrodeposition liquid bath and the electrodeposition liquid in the bath was slightly stirred.

Next, the image holding member after the completion of the image formation is taken out of the liquid, an image having an optical image density of 1.48 is formed on the surface of the image holding member, and the optical density variation of the solid portion is σ = 0. .04. On the other hand, in the same evaluation, the optical image density of the image formed in Example 1 was 1.42, and the optical density variation of the solid portion was σ =
Since it was 0.09, it was found that stirring the inside of the electrodeposition bath slightly was useful for improving the optical image density and the uniformity of the image.

Example 9 The same electrodeposition solution as in Example 2 was completed in the same manner as in Example 2.

Next, by using the same apparatus as that of the embodiment 2 shown in FIG. 8, He-Ne is applied to the optical image input section on the back surface of the image holding member.
2.5 V between the work electrode and the counter electrode from the potentiostat power supply while inputting an image with laser light
D. C. Pulse voltage (pulse width 2 ms / pulse period 3
ms). At that time, an image was formed at a constant temperature (40 ° C.) while a temperature controller was placed in the electrodeposition bath and the temperature of the electrodeposition solution in the bath was controlled.

Next, the image holding member having completed the image formation is taken out of the liquid to form an image having an optical image density of 1.49 on the surface of the image holding member, and the optical density variation of the solid portion is σ = 0. .05. On the other hand, in the same evaluation, the optical image density of the image formed in Example 2 was 1.48, and the optical density variation of the solid portion was σ =
From 0.09, it can be seen that controlling the liquid temperature of the colorant liquid in the colorant electrodeposition liquid bath to be constant is useful for improving the optical image density and the image uniformity. Was.

Example 10 In the same manner as in Example 3, an electrodeposition liquid was prepared, and the image holding member having an image formed on the surface thereof was taken out of the electrodeposition liquid bath through an image forming step. Plain paper was placed on the surface of the flat member on which the image containing the coloring material particles was formed.

Using a conductive rubber roller and an insulating rubber roller,
A pressure was applied between the plain paper and the image holding member at a linear pressure of 300 g / cm, a bias voltage of +600 V was applied to the conductive rubber roller, and the sheet was rotated and conveyed. And immediately after unloading the rollers,
The plain paper is peeled off from the image holding member, and an optical image density of 1.
Thirty-eight transferred images were obtained on plain paper.

Next, the transfer residual image forming material on the surface of the image holding member was removed using a rubber blade. As a result, the surface of the image holding member returns to the initial state, and the preparation for the next image formation is completed. At this time, the critical surface tension of the surface of the image holding member was 35 dyne / cm.

Example 11 Surface image formation was performed in the same manner as in Example 3 except that an electrodeposition solution similar to that of Example 3 was prepared and an image holding member having a critical surface tension of 44 dyne / cm was used. After the process, the image-holding member having the image formed on the surface was taken out of the electrodeposition liquid bath, and plain paper was placed on the surface of the flat member surface of the image-holding member on which the image containing the colorant particles was formed.

The conductive rubber roller and the insulating rubber roller are applied with a linear pressure of 3.
The sheet was pressed at 00 g / cm with the plain paper and the image holding member interposed therebetween, and a bias voltage of +500 V was applied to the conductive rubber roller to carry the sheet by rotation. Then, the plain paper was peeled off from the image holding member immediately after the roller was carried out, and a transferred image having an optical image density of 1.18 was obtained on the plain paper.

Next, the transfer residual image forming material on the image holding member surface was removed using a rubber blade. However, the image forming material partially remained in the thin film state, and the surface of the image holding member did not return to the initial state. From this, it was found that if the critical surface tension of the surface of the image holding member is too large, the surface of the image holding member easily returns to the initial state, and is suitable for reuse.

Example 12 An image forming process was performed in the same manner as in Example 2 except that an electrodeposition solution similar to that of Example 2 was prepared, and an image holding member having a critical surface tension of 18 dyne / cm was used. After that, the sheet was taken out of the electrodeposition bath, a color material image was obtained on the image holding member, and plain paper was placed on the image holding member surface. From above the paper, apply a conductive rubber roller and insulating rubber roller at a linear pressure of 300 g.
/ Cm between the plain paper and the image holding member, and +6
A bias voltage of 00 V was applied to the conductive rubber roller, and the sheet was rotated and transported. Then, the plain paper was peeled off from the image holding member immediately after the roller was carried out, and a transferred image having an optical image density of 0.88 in a solid portion was obtained on the plain paper. However, the line image caused a flow and showed poor reproduction. From this, it was found that if the critical surface tension of the flat member surface of the image holding member was too low, the holding ability of the image formed on the image holding member surface was deteriorated.

Next, the transfer residual image forming material on the image holding member surface was removed using a rubber blade. As a result, the surface of the image holding member returns to the initial state, and the preparation for the next image formation is completed.

Example 13 Styrene-methacrylic acid copolymer (molecular weight: 16,000, molar ratio of hydrophobic group / (hydrophilic group + hydrophobic group): 69, acid value: 160) 160% by weight of a 20% by weight aqueous alkali solution Parts, 5 parts by weight of carbon black powder (average particle diameter: 0.1 μm), 15 parts by weight of diethylene glycol, 7 parts by weight of isopropanol,
The above materials were mixed with 55 parts by weight of distilled water, and a medium-strength propeller was stirred for 1 hour to sufficiently wet the carbon bulk powder into a liquid to prepare a coarse dispersion. Next, the dispersion liquid was subjected to a high-intensity forced dispersion treatment for 3 minutes using a homogenizer disperser to prepare a dispersion stock solution. 120 parts by weight of distilled water, 10 parts by weight of glycerin, fungicide (ICI
A mixed solution of 0.3 parts by weight of Proxel XL-2) was dropped into this dispersion stock solution while stirring with a propeller to complete an electrodeposition solution. The pH of this solution was adjusted with an aqueous hydrochloric acid solution and an aqueous sodium hydroxide solution to adjust the pH.
The values were set to 4.6, 6.0, 7.5 and 9.5. The pH of the liquid at the start of colorant particle deposition is 5.0. Then, the pH point at which complete precipitation of the supernatant was obtained was 4.4.

Next, as shown in FIG. 4, the image holding member provided with the work electrode from which the image signal can be inputted from the back side is put into the electrodeposition bath containing the above-mentioned electrodeposition solution, and the back side goes out of the bath. And a control electrode utilizing a salt bridge was installed in the bath. This image holding member is made of a laminated structure of a two-layer organic photoconductor layer on which a transparent conductive layer of ITO is provided on a 4 mm-thick soda lime glass substrate, and the ITO conductive layer is used as a work electrode, and an organic photoconductor is formed. The surface of the layer was smooth. Each electrode was connected to a potentiostat power supply. Then, while inputting an image to the optical image input section on the back surface of the image holding member, a 2.6 V D.V. C. Voltage 7
Seconds.

Next, the image-holding member on which the image formation was completed was taken out of the liquid, and the optical image density of the surface of the image-holding member was measured. As a result, 1.35 (electrodeposition solution of pH 4.6),
It was confirmed that images of 43 (electrodeposit at pH 6.0), 1.39 (electrodeposit at pH 7.5), and 1.05 (electrodeposit at pH 9.5) were formed. Here, in the electrodeposition solution having a pH of 4.6, the coloring material particles were settled at the bottom of the bath, and the dispersion state was unstable.

As described above, according to the image recording method of the present invention, the color material particles are contained in the image holding member capable of supplying a current corresponding to the image signal to the electrodeposition liquid containing the electrodeposition material. An image is formed by the deposition phenomenon of an electrodeposited material.Because an image can be formed at a predetermined position by applying a voltage or irradiating a laser beam, recording with excellent resolution can be performed and high optical density can be obtained. A record having printing characteristics such as high resolution, low image thickness image structure, strong image adhesiveness, good halftone reproduction, high image fastness, and high safety can be obtained.

[0117]

As described above, according to the present invention,
The number of hydrophobic groups in the monomer unit of the electrodeposition material is such that the ratio of the total number of hydrophilic groups to hydrophobic groups is in the range of 40% to 80%, and the average molecular weight of the electrodeposition material is 4,000 to 3%.
When the pH is in the range of 0000 and the acid value is in the range of 60 to 300, the pH range of the change which causes precipitation from the dissolved state to the change in the pH value of the electrodeposition solution is within 1 By forming an image by the electrodeposition phenomenon using an image holding member capable of flowing current, high optical density, high resolution,
An image having a printing characteristic with a low image thickness image structure, high image fastness, and high safety can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a change in pH of an aqueous colorant liquid and a dissolution characteristic of the colorant.

FIG. 2 is a graph showing the relationship between the molar ratio of a hydrophobic group to a (hydrophobic group + hydrophilic group) of an electrodeposition material and the water resistance of the film.

FIG. 3 is a graph showing the concept of film water resistance and deposition characteristics of an electrodeposition material.

FIG. 4 is a schematic diagram illustrating an image recording apparatus used for image recording according to the first embodiment.

FIG. 5 is a conceptual diagram showing an image recording phenomenon due to deposition of an electrodeposited material.

FIG. 6 is a conceptual diagram showing a structure of electrodeposited particles in an electrodeposition liquid.

FIGS. 7A to 7C are schematic diagrams showing an image forming and recording process of the present invention.

FIG. 8 is a schematic diagram illustrating one embodiment of an image recording system of the present invention using an image recording apparatus having a belt-shaped image holding member.

FIG. 9 is a schematic diagram illustrating an image recording apparatus including a laser generator used for image recording according to the second embodiment.

FIG. 10 is a schematic diagram illustrating an image recording apparatus including an LED print head used for image recording according to a third embodiment.

[Explanation of symbols]

 Reference Signs List 1 water-based colorant for electrodeposition 2 liquid bath 3 image holding member 4 potentiostat power supply 5 counter (counter) electrode 6 control electrode

Claims (20)

[Claims] 1. An image holding member having at least an electrode capable of supplying a current or an electric field according to an image pattern and a surface capable of holding an image, and a counter electrode which is the other of the electrode pair, in a container capable of holding a liquid. In the container of the arranged device,
An aqueous dispersion containing a fine particle coloring material and an electrodeposition material containing a polymer compound that is chemically dissolved or precipitated / precipitated due to a change in pH is prepared, and current or current is applied to the image holding member and the counter electrode according to an image pattern. An image formation recording method for forming an image by applying an electric field and changing the pH of the dispersion near the surface of the image holding member to deposit and settle an electrodeposited material containing a fine particle colorant, thereby forming an image. The electrodeposition material comprising a molecule has both a hydrophobic group and a hydrophilic group in the molecule, and the number of hydrophobic groups in the polymer is in the range of 40% to 80% of the ratio of the total number of the hydrophilic group and the hydrophobic group. 50% or more has the property of being able to reversibly change from a hydrophilic group to a hydrophobic group by a change in pH, and has an acid value of 30 to 40.
An image forming and recording method comprising a copolymer which is 0. 2. The method according to claim 1, further comprising the step of transferring and fixing an electrodeposition material containing a fine particle coloring material deposited and settled in an image pattern on the surface of the flat member holding the image of the image holding member to a recording medium. The image forming and recording method according to claim 1. 3. A means for applying a current or an electric field to the image holding member and the counter electrode, comprising a mechanism for converting a light image signal into a current in response to a light image signal input, wherein the light image is provided on the surface of the image holding member. 3. The image forming and recording method according to claim 1, wherein said means is a means for generating a current in response to a signal. 4. The method according to claim 1, wherein the hydrophilic group capable of reversibly changing from a hydrophilic group to a hydrophobic group by changing the pH has a carboxyl group or an amino group. Image formation recording method. 5. The electrodeposition material made of a polymer according to claim 1, wherein the hydrophobic group portion contains at least one of a styrene unit and an α-methylstyrene unit. Image forming recording method. 6. A method according to claim 1, wherein said color material particles are ionized particles having a polarity opposite to the polarity of the image pattern attaching portion of the image holding member, and the potential difference between the image pattern attaching portion of the image holding member and the reference electrode is reduced. 6. The image forming and recording method according to claim 1, wherein the image is formed using an applied voltage within ± 5 V. 7. When the image pattern generating section is more anodic than the reference electrode, the electrodeposited material becomes an anionic group by dissociating a carboxyl group, which is a hydrophilic group portion of the electrodeposited material, in an aqueous liquid. The electrodeposition material is a structural substance, and at the same time, a part of the electrodeposition material is bonded, adhered or associated with the surface of the coloring material particles, and the acid value of the electrodeposition material is in a range of 60 to 300. Item 7. The image forming and recording method according to any one of Items 1 to 6. 8. When the image pattern generating portion is more cathodic than the reference electrode, the electrodeposited material becomes a cation group by dissociating an amino group, which is a hydrophilic group portion of the electrodeposited material, in an aqueous liquid. 7. The image forming / recording method according to claim 1, wherein the material is a structural material, and at the same time, a part of the electrodeposited material is bonded, adhered or associated with the surface of the colorant particles. . 9. The electrodeposition material having an average molecular weight of 4,0.
It contains a thermoplastic resin component in the range of 00 to 30,000, and has a pH value change region between a dissolved state (transparent) with respect to a change in pH of the aqueous solution of the electrodeposition material and a precipitated state that produces a supernatant liquid. 2. The method according to claim 1, wherein the distance is within 1.0.
9. The image forming and recording method according to any one of claims 1 to 8. 10. A surface roughness (R) of the surface of the image holding member.
The image formation recording method according to any one of claims 1 to 9, wherein a) is from 0.01 µm to 1.2 µm, and the critical surface tension is from 20 dyne / cm to 40 dyne / cm. 11. The image forming and recording method according to claim 1, wherein the form of the image holding member is a belt shape. 12. The aqueous dispersion liquid contains a water-soluble polymer material, and in the image forming step, the water-soluble polymer material adheres to the image pattern portion on the surface of the image holding member as a part of the image forming material. The image forming and recording method according to claim 1, wherein: 13. The aqueous dispersion liquid having a boiling point of 120 ° C.
The image forming and recording method according to claim 1, further comprising a water-soluble solvent having a vapor pressure in the atmosphere of 50 mmHg or less. 14. The image forming apparatus according to claim 1, wherein an average particle diameter of the fine particle coloring material in the aqueous dispersion is in a range of 0.02 μm to 0.3 μm. Recording method. 15. The aqueous dispersion liquid having a conductivity of 10 ⁵ Ω ·
The image forming and recording method according to any one of claims 1 to 9, wherein the diameter is equal to or less than 10 cm. 16. A container in which the aqueous dispersion is disposed,
10. The image forming / recording method according to claim 1, further comprising means for flowing or stirring the aqueous dispersion. 17. A container in which the aqueous dispersion is disposed,
10. The image forming and recording method according to claim 1, further comprising means for controlling the temperature of the aqueous dispersion. 18. An image forming material used in the image forming and recording method according to claim 1, wherein the fine particle color material and p
An aqueous dispersion containing a polymer electrodeposition material that chemically dissolves or precipitates and precipitates due to a change in H. The polymer electrodeposition material has both a hydrophobic group and a hydrophilic group in the molecule. The number of hydrophobic groups in the polymer is in the range of 40% to 80% of the ratio of the total number of hydrophilic groups to hydrophobic groups, and at least 50% of the hydrophilic groups are reversibly changed from hydrophilic groups to hydrophobic groups due to a change in pH. It has properties that can be obtained, and has an acid value of 30 to 400.
An image-forming material comprising a copolymer represented by the formula: 19. The pH value of the aqueous dispersion is 1 ± 1 pH from the deposition start pH point when the electrodeposition material is an anodic deposition method.
PH value of 2 is set, and when the electrodeposit is a cathodic deposition, the pH value is set to a value of -1 ± 2 from the deposition start pH point. The image forming material according to claim 18. 20. The electrodeposition material according to claim 1, wherein the hydrophilic group has a carboxyl group or an amino group, and the hydrophobic group contains at least one of a styrene unit and an α-methylstyrene unit. 19. The image forming material according to 18.