JP2002264517A - Method and apparatus for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method capable of forming images precisely at a high speed, and an image forming apparatus therefor. SOLUTION: The image forming method comprises a latent image forming process wherein a latent image forming liquid containing a transferability accelerating material capable of lowering of a transfer temperature of a thermal transfer material or an adhesive material is discharged like an image from a plurality of nozzles onto either the surface of a transfer recording layer of an image transfer material having the transfer recording layer constituted of the thermal transfer material and provided on a substrate, or the image receiving surface of an image receiving sheet having an image receiving layer containing a binder resin, so as to form a latent image, and a transfer process wherein the surface of the transfer recording layer of the image transfer material and the image receiving surface of the image receiving sheet are brought into close contact with each other and heated, so as to transfer the transfer recording layer corresponding to the latent image onto the image receiving sheet. In the image forming method and the image forming apparatus, the nozzles do not move substantially in relation to the surface of the transfer recording layer or the image receiving surface and the latent image forming liquid is discharged from the nozzles simultaneously or sequentially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming method to which a thermal transfer system is applied and an image forming apparatus used therefor.

[0002]

2. Description of the Related Art A thermal transfer method is one of the methods for forming an image on a transfer member such as paper or film. This thermal transfer method
A transfer body (transfer sheet) having a transfer layer made of a pigment-based dye, which is a transfer material, formed on the surface of a support is superimposed on an image receiver (image receiving sheet) such as paper or film, and thermal transfer is performed from the back side of the support of the transfer sheet. Heat is applied imagewise with a head, a laser head, or the like, and the dye is transferred to the image receiving sheet to form an image on the image receiving sheet. As another mode of such a thermal transfer method, there is a method in which a dye placed on a transfer body is sublimated by heating and transferred to an image receiving sheet.

In the thermal transfer method using a thermal head for imagewise heating, the temperature distribution tends to be non-uniform due to variations in the head resistance value, and as a result, the formed image becomes uneven. There was a problem. In addition, since local high-temperature heating is performed only on the image portion, the support of the heated portion is deformed, and there is a problem that wrinkles are easily generated. In addition, as a means for improving the uniformity of the image, there is a method using laser light for heating in the thermal transfer method, but the apparatus cost is expensive, and furthermore, materials such as dyes are decomposed by local high-temperature instantaneous heating, There is a problem that unevenness is likely to occur in the finally formed image.

In contrast to these image forming methods, as a non-contact image forming method which does not affect an image receiving sheet or a coloring material for forming an image, there is an ink jet system in which ink is ejected as droplets to form an image. There are various types of ink jet systems, such as piezo type, thermal type, and Hertz type. These are described in “Journal of Science and Technology”, Vol. 42, No. 1 (1996, USA)
In detail. Here, the piezo type will be described. In the piezo type, a plurality of nozzle holes in which ink heads are arranged side by side, an independent discharge chamber communicating with the nozzle holes, and a part of a wall serving as a diaphragm, and a piezoelectric element mounted on the diaphragm, A common ink cavity that supplies ink to the ejection chamber is formed. By applying a pulse voltage based on image information to the piezoelectric element, an ink droplet is ejected from a nozzle hole to form an image on an image receiving sheet. Is what you do.

In this ink jet system, although there is no problem of the deformation of the support and the deterioration of the color material due to the heat at the time of recording as described above, clogging of ink nozzles is prevented, and a uniform ink drop is formed stably. For this reason, there are many restrictions on the image forming material due to the physical properties of the liquid, and the image forming material cannot be freely selected. Even when forming a color image, it is necessary to select a dye or a specific pigment in order to prevent nozzle clogging, and there is a limitation on hue reproducibility in the image, for example, to reproduce the same hue as the printing ink pigment. However, it cannot be applied to a high-precision printer for printing proof which requires a high accuracy. Further, if not used for a long time it is employed constrained image forming material, there is a nozzle clogging problem. Further, there is also a problem that the light resistance and water resistance of the formed image are low, and the dye tends to blur on the image receiving sheet.

As an image forming method to which the ink-jet method is applied, for example, Japanese Patent Application Laid-Open No. H11-70633 discloses a method in which a cross-linking agent droplet is applied imagewise to a recording layer made of a cross-linkable material by an ink-jet apparatus. A method is disclosed in which an image is formed by crosslinking and curing the crosslinked portion and removing the material of the non-crosslinked portion by washing. In this method, a so-called screen printing plate is formed by using an ink jet, and then an image is formed by using a colored ink. This is completely different from the transfer method of the present invention, and has two steps of plate making and printing. In addition, since the plate making requires a developing step, there is a problem of cleaning waste liquid treatment and the like, and a complicated step is required. In addition, there is a so-called transfer type ink jet system in which an image formed of a recording liquid containing a liquid and a colorant is formed on an image carrier by an ink jet recording system, and the image is transferred onto a transfer target (for example, a special type of ink jet system). Kaihei 5-42755). This method is a normal ink jet recording method, for example, in which an image containing a dye is once recorded on an image carrier on a drum, and an image is transferred to a transfer target again. However, problems such as limitations on color materials and nozzle clogging remain. In addition, only an image having a low resolution is easily obtained.

Further, as an ink-jet recording method using a transfer medium, Japanese Patent Application Laid-Open No. Hei 7-145576 discloses that an ink-jet ink is imagewise landed on a transfer medium having a liquid-reactive resin layer on the uppermost layer by an ink-jet recording apparatus. , which was in close contact with the image support (fabric, etc.), consists in transferring the image portion is heated and pressurized, in particular,
An image forming method capable of printing on a fabric is described.
For example, when the ink is an aqueous ink, the liquid-reactive resin layer is made of a water-soluble resin, and when an ink droplet lands, that portion dissolves and becomes tacky (adhesive). Since only the landing portion is transferred, a high-definition image can be formed on the fabric using the inkjet method. However, this method is particularly intended for a cloth as an image support, and uses ink-jet ink to the last. Therefore, similar to general ink-jet recording, there are problems such as limitations on color materials and nozzle clogging. There is a problem that the toner remains as it is, and the transfer cannot be performed uniformly, causing unevenness.

In addition, Japanese Patent Application Laid-Open No. Sho 62-117782 discloses a method in which a solvent is applied imagewise to the surface of an image carrier using an ink jet discharge method, and then an ink layer is brought into contact with the image carrier. , the ink layer, only the parts in contact with the imagewise solvent, an image forming method for forming the image bearing member is described. However, this method requires a solvent having an appropriate cohesive force and adhesive force as described in the upper right column of page 4 of the above publication, line 7 to 16, so that it is difficult to select a solvent. Further, although a synthetic resin film is shown as an image carrier, since it is not solvent-acceptable like a binder coating layer, it is very difficult to stably achieve good transferability. Further, the above method does not sufficiently reproduce fine dots, and in particular, cannot obtain a multi-color transfer image with high resolution. Japanese Patent Application Laid-Open No. Hei 7-276780 is an improvement of the image forming method of Japanese Patent Application Laid-Open No. Sho 62-117782. As a method of applying a solvent imagewise to a recording medium, a porous material impregnated with a solvent is used. A method in which thermal energy is applied to a substrate in accordance with image information and an impregnating liquid is released as mist (microdroplets) or vapor onto a recording medium, and there is no clogging because an inkjet discharge method is not used. And the like. However, this method is the same as that of JP-A-62-117782 except that mist or vapor is applied to the recording medium, and thus the same problem as described above remains.

As an image forming method for solving these problems, the present inventors have previously proposed an image transfer material having a transfer recording layer made of a thermal transfer material on a support and an image receiving layer containing a binder resin. As an image forming method using an image receiving sheet, a transfer accelerating material or an adhesive material capable of lowering the transfer temperature of the thermal transfer material is contained on either the transfer recording layer surface of the image transfer material or the image receiving surface of the image receiving sheet. After the latent image is formed by applying the liquid imagewise, the surface of the transfer recording layer of the image transfer material and the image receiving surface of the image receiving sheet are brought into close contact with each other and heated, and the transfer recording layer corresponding to the latent image is placed on the image receiving sheet. (Japanese Patent Application 2000-)
163273, Japanese Patent Application No. 11-288179).

The above-mentioned image forming method solves the problems of the limitation of the image forming material and the problem of clogging of the nozzles, which are disadvantages of the ink jet system. An improved image with excellent hue reproducibility can be formed.In addition, the transferability and resolution of fine points are also excellent.Especially when forming multi-color images, it is significantly better than the conventional thermal transfer method. An excellent image is formed. However, in the above-described image forming method, image recording is performed by reciprocating the surface of the image receiving sheet in the same direction or at a right angle to the moving direction of the recording medium, and the recording speed is determined by the movement of the nozzle head. Since the speed depends on the speed, there is a limit in increasing the speed in terms of the mechanical structure of the apparatus, and there is still room for improvement in the accuracy of the position where the droplet of ink or the like lands.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems, and it is an object of the present invention to provide a high-speed image forming apparatus capable of accurately forming an image. An object of the present invention is to provide an image forming method and an image forming apparatus for the image forming method.

[0012]

The above object is attained by providing the following image forming method and image forming apparatus. (1) Either on the surface of a transfer recording layer of an image transfer material having a transfer recording layer made of a thermal transfer material on a support or on the image receiving surface of an image receiving sheet having an image receiving layer containing a binder resin.
A latent image forming step of forming a latent image by discharging a latent image forming liquid containing a transferability promoting material or an adhesive material capable of lowering the transfer temperature of the thermal transfer material from a plurality of nozzles in an image-like manner,
A step of heating the transfer recording layer surface of the image transfer material and the image receiving surface of the image receiving sheet in close contact with each other, and transferring a transfer recording layer corresponding to the latent image onto the image receiving sheet; An image forming method, wherein a plurality of nozzles does not substantially move with respect to the surface of a transfer recording layer or an image receiving surface, and the latent image forming liquid is discharged simultaneously or sequentially from a plurality of nozzles. (2) the plurality of nozzles form a plurality of groups;
The image forming method according to (1), wherein the image forming apparatus is driven sequentially in units of the group. (3) The nozzle according to (1), wherein the nozzle is minutely moved in one or more directions, and the latent image forming liquid is ejected to a transfer recording layer surface or an image receiving surface at a location different from the ejection location before the movement. Or the image forming method according to (2). (4) The image forming method according to any one of (1) to (3), wherein the minute movement is smaller than a nozzle pitch. (5) The nozzle is minutely moved in one or more directions, and the latent image forming liquid is ejected to substantially the same location as the ejection location on the transfer recording layer surface or image receiving surface before the movement. The image forming method according to 1) or 2).

(6) An image forming apparatus for transferring a transfer recording layer of an image transfer material in which a transfer recording layer made of a thermal transfer material is provided on a support to an image receiving sheet having an image receiving layer containing a binder resin. Then, a droplet of a latent image forming liquid containing a transferability promoting material or an adhesive material capable of lowering the transfer temperature of the thermal transfer material is imagewise formed on either the transfer recording layer surface or the image receiving surface of the image receiving sheet. A nozzle head, which has a plurality of nozzles and is substantially fixed, which ejects and forms a latent image, is brought into close contact with the surface of the transfer recording layer of the latent image forming liquid and the image receiving surface of the image receiving sheet, and is passed therethrough. An image forming apparatus comprising: a pair of pressure rollers having heating means capable of controlling a heating temperature in at least one of the pressure rollers.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The image forming method according to the present invention is a method for thermally transferring an image on a transfer recording layer surface of an image transfer material having a transfer recording layer made of a thermal transfer material on a support or an image receiving surface of an image receiving sheet having an image receiving layer containing a binder resin. A latent image forming step of forming a latent image by imagewise applying a latent image forming liquid containing a transferability promoting material or a tacky material capable of lowering the transfer temperature of the material from a plurality of nozzles, and Heating the transfer recording layer surface and the image receiving surface of the image receiving sheet in close contact with each other, and transferring the transfer recording layer corresponding to the latent image onto the image receiving sheet. The method is characterized in that the transferability promoting material or the solution is discharged simultaneously or sequentially from a plurality of nozzles without substantially moving with respect to the recording layer surface or the image receiving surface.

"A plurality of nozzles do not move substantially with respect to the surface of the transfer recording layer or the image receiving surface" means that the head provided with the nozzles reciprocates on the image transfer material or the image receiving sheet as in the above-mentioned prior art. Means not. Therefore, it is necessary that a plurality of nozzles in the image forming method of the present invention are provided at least corresponding to the image forming area. For example, when the image receiving sheet has a size corresponding to a postcard or various types of cards (various prepaid cards such as telephone cards, cash cards, etc.), a plurality of nozzles cover these image forming areas. And a plurality of nozzles arranged vertically and horizontally corresponding to the card. FIG. 1 shows an example. A plurality of nozzles shown in FIG. 1 are provided corresponding to the image forming area of the image receiving sheet. 13A is a nozzle head provided with a plurality of nozzles 10. The arrangement of the plurality of nozzles is not particularly limited. As shown in FIG. 1, the nozzles may be arranged in a grid in the X direction and the Y direction, or may be arranged in a staggered manner. The diameter of each nozzle is 15 to 80 μm, preferably 20 to 50 μm. The nozzle pitch (the length connecting the center points of two adjacent pitches) is determined in both the X and Y directions.
35-500 [mu] m, preferably 70-170 [mu] m is suitable.

In the present invention, a plurality of nozzles (nozzle heads)
The latent image forming liquid is discharged in a state in which the latent image is fixed without being substantially moved to form a latent image. Then, when forming a latent image, a plurality of nozzles are driven at a time, or a plurality of nozzles are divided into a plurality of groups, and the groups are sequentially driven to discharge droplets. Therefore, since the nozzle (nozzle head) does not need to be reciprocated and does not substantially move as in the prior art, high-speed image formation is possible, and the accuracy of the landing position of the liquid droplet can be increased. A fine image can be obtained. Also,
As in the case of forming an image by an ink jet method using a nozzle group as in the present invention (Japanese Patent Application Laid-Open No. 2000-15846), it is not necessary to provide a nozzle of a type corresponding to the number of colors by making the nozzle pitch extremely small. In addition, since the system for supplying ink does not become complicated, there is an advantage that it is relatively easy to manufacture a nozzle head.

On the other hand, in the present invention, "the plurality of nozzles do not substantially move with respect to the transfer recording layer surface or the image receiving surface".
This does not exclude the following “small movement”. “Small movement” means, for example, small movement in the X direction and / or the Y direction in FIG.
For example, the nozzle (nozzle head) is minutely moved in one or more directions, for example, is moved by a distance smaller than the pitch of the plurality of nozzles, and is ejected to a transfer recording layer surface or an image receiving surface at a location different from the ejection location before the movement. Thereby, higher resolution is achieved. In addition, the nozzles are moved in one or more directions by a minute distance, for example, one pitch or more, and ejected by a different nozzle at substantially the same place as the ejection place before the movement on the surface of the transfer recording layer or the image receiving surface. A plurality of droplets are ejected to a location, and the “ejection clogging” of each nozzle is canceled, so that image unevenness can be removed. At this time, if necessary, the concentration of the transfer promoting material or liquid supplied to the plurality of groups of nozzles can be made different.

[Latent Image Forming Liquid] Next, the latent image forming liquid used in the present invention will be described. As the latent image forming liquid of the present invention, a liquid containing a transferability promoting material capable of lowering the transfer temperature of a thermal transfer material or a liquid containing an adhesive material is preferably used. (Liquid Containing a Transferability-Promoting Material That Can Lower the Transfer Temperature of a Thermal Transfer Material) Examples of the transfer-promoting material include organic solvents and surfactants. Among them, organic solvents freely miscible with water at room temperature, surfactants miscible with water, and mixtures thereof are desirable. In addition, the transferability-promoting material does not contain a solid pigment or a compound that precipitates with time from the viewpoint of stability over time and no fear of clogging of the nozzle, and further uses a coloring material for the transfer recording layer. When it does, from the viewpoint that it does not affect the color tone, it is a material that does not chemically act on the coloring material and does not cause a coloring reaction or the like even by applying energy such as heating, and is itself colorless or Light color is desirable. If the transferability-promoting material can be stably discharged from the nozzle as it is, like an organic solvent, it is not necessary to dilute it with water or the like. It is used after being diluted with a neutral organic solvent.

Examples of the organic solvent freely miscible with water, which is a transfer promoting material, include methyl alcohol,
Ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, ethylene glycol, diethylene glycol, thiodiethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, 1,2,
6-hexanetriol, hexylene glycol, polypropylene glycol, monohydric or polyhydric alcohols such as glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether,
Ethers such as tripropylene glycol monomethyl ether, keto alcohols such as diacetone alcohol,
There are nitrogen-containing solvents such as N-methyl 2-pyrrolidone and 2-pyrrolidone. As the water-miscible surfactants, any of anions, cations, nonionics and amphoteric surfactants can be arbitrarily selected according to the properties of the thermal transfer material used, but they can be dissolved in water. Can be used at concentrations within the range. Specifically, fatty acid salts, alkyl sulfate salts, polyoxyethylene alkyl ether sulfate salts, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, alkyl phosphates,
Examples include naphthalene sulfonate formalin condensate, polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, alkyl alkanolamine, alkylamine salt, and alkyl betaine.

Each of the above materials can be selected and used according to the characteristics of the thermal transfer material.
Mixtures of more than one species may be used. Above all, it is desirable from the viewpoint of effects to use hydrophilic organic solvents, surfactants, and the like individually or in an appropriate combination, mixed with water. When adjusting the liquid composition of the transferability promoting material, the surface tension adjusting material, the antifungal agent, and the viscosity adjusting are used for the purpose of adjusting the discharge suitability, improving the storage stability of the liquid, preventing the diffusion of the ejected droplets, and the like. Materials, pH adjusters, defoamers, and the like can be used in combination as long as the effects of the present invention are not impaired.

The transferability-enhancing material is used for the purpose of improving the transferability of an arbitrary portion of the transfer recording layer made of a thermal transfer material so that the transfer can be easily and completely performed at a lower transfer temperature. It is. The transferability promoting material is
At least partially penetrate into the transfer recording layer or the image receiving layer,
The material for facilitating the peeling of the transfer recording layer from the support, and the transferability-promoting material preferably has a surface tension of 20 to 60 mN /
m, viscosity 50 mPa. It is a liquid having the following physical properties.
It is desirable that the amount of the transferability-promoting material applied to the transfer recording layer or the image receiving layer be kept within a range that does not reduce the resolution of the transferred image. If the amount is too large, penetration of the transferability-promoting material at the interface between the image area and the non-image area and the dissolution and flow of the transfer recording layer may occur, and the sharpness of the image interface may be reduced.
Here, as a criterion for lowering the transfer temperature, it is preferable that the transfer temperature be lowered by 3 ° C. or more by adding the transferability promoting material to the original transfer temperature of the transfer recording layer. It is considered that the function of the transfer promoting material is that the binder resin contained in the transfer recording layer or the image receiving layer is plasticized or swelled. This transfer temperature can be measured by the following method.

As shown in FIG. 2, an apparatus having a pair of heating nip rollers having a heating roller with a variable temperature, a thermocouple is sandwiched between the transfer material and the image receiving sheet, and the temperature is controlled by the thermocouple while passing through the heating nip roller. Measure. The measurement is performed while changing the heating temperature, and the lowest temperature at which transfer occurs is defined as the transfer temperature.

In the image forming method of the present invention, when a nonionic surfactant is used as a transferability promoting material,
The effect of lowering the transfer temperature is great, and the transferability of fine points is good, so that a transferred image with high resolution can be obtained. The reason for this is not always clear, but because of good wettability and permeability to the transfer layer or the image receiving layer, it is necessary to sharply form a latent image of fine dots. It is considered that the resin has a high effect as a plasticizer for the resins used, and as a result, the adhesiveness of the latent image forming portion due to heat is developed, and the transfer effect is obtained. Further, the permeated nonionic surfactant may be oriented at the interface between the support of the transfer layer and the coating layer to promote peel transfer. In addition, among nonionic surfactants, the use of a nonionic compound having an ethylene oxide group added as a hydrophilic group, among others, has found that the effect of lowering the transfer temperature in the latent image forming portion is large and that high resolution can be obtained. Was. Examples of the nonionic compound include compounds represented by the following general formulas 1 to 4.

[0024]

Embedded image

In the above general formula 1, R represents an alkyl group or an alkylene group, and n is 2 to 30, preferably 2
Represents an integer of 20 to 20, in the general formula 2, R represents an alkyl group, n represents an integer of 2 to 30, preferably an integer of 2 to 20,
In the general formula 3, R represents hydrogen or an alkyl group;
And 1 represents an integer of 2 to 30, preferably 2 to 20,
In the general formula 4, R ₁ and R ₂ represent hydrogen or an alkyl group, and m and n are 2 to 30, preferably 2 to 2,
Indicates 0 integer. In the above general formulas 1-4, the number of additions of ethylene oxide is preferably 2 to 30, and particularly preferably 2 to 20. Specific examples of the compounds represented by the above general formulas 1-4 include polyoxyethylene (4) lauryl ether, polyoxyethylene (7) cetyl ether, polyoxyethylene (13) stearyl ether, polyoxyethylene (5) oleyl ether, and polyoxyethylene (5) oleyl ether. Oxyethylene
(10) Nonylphenyl ether, ethylene oxide-propylene oxide copolymer (n = 10, l = 7), ethylene oxide adduct of acetylene glycol (n + m =
10) and the like, but are not limited thereto.

The nonionic surfactant is added in an amount of 0.1 to 20% by weight, preferably about 0.1 to 10% by weight, in the discharged liquid. If the amount exceeds 20% by weight, the resolution tends to decrease. On the other hand, when the amount is less than 0.1% by weight, it is difficult to obtain the transferability promoting effect. In addition to the nonionic surfactant, a water-soluble organic solvent can be appropriately added. As the water-soluble organic solvent, the above-mentioned organic solvents that are freely miscible with water can be used. The content of the water-soluble organic solvent is 0 to 90% by weight in the solution.
The degree is appropriate. In particular, when the content of the solvent having a boiling point of 100 ° C. or more is large, the ejection stability at the time of forming the latent image is increased, but the drying property of the transferred image is reduced. The optimum solvent type and the amount used are determined by the necessity of drying the transfer member and the drying capacity of the apparatus. Furthermore, in order to impart ejection suitability and storage stability of the liquid, a surface tension adjusting material, a fungicide, a viscosity adjusting material such as a polymer, a pH adjusting material, a defoaming material, and the like can be used in combination.

Further, in the image forming method of the present invention,
Water and a boiling point of 1 under normal temperature and normal pressure
By using a solution containing an organic solvent having a temperature of 00 ° C. or higher and having compatibility with water, the ejection stability of the solution is improved, so that the non-ejection phenomenon at the time of forming a latent image and restarting after standby can be prevented. In addition, since the transferability of fine dots is improved, a high-resolution transfer body can be obtained. Examples of the organic solvent having a boiling point of 100 ° C. or higher at normal temperature and normal pressure and having compatibility with water include ethylene glycol, diethylene glycol, thiodiethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, and glycerin.
Polyhydric or polyhydric alcohols, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol Ethers such as monobutyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, and tripropylene glycol monomethyl ether; keto alcohols such as diacetone alcohol; nitrogen-containing solvents such as N-methyl 2-pyrrolidone and 2-pyrrolidone And the like.

These organic solvents are contained in the solution in an amount of 1 to 90% by weight. When the content exceeds 90% by weight, the ejection stability at the time of forming a latent image increases, but the drying property of the transferred image tends to decrease. If the amount is less than 1% by weight, it becomes difficult to improve the ejection stability and transferability of fine dots. The optimum amount is determined by the need for drying the transfer member and the drying capacity of the apparatus. Further, as a material for lowering the transfer temperature, in addition to the above-mentioned organic solvent, the above-mentioned organic solvents which are freely miscible with water and the above-mentioned surfactants can also be added. Further, a surface tension adjuster for improving discharge suitability and storage stability of the liquid, a fungicide, a viscosity adjuster such as a polymer, and a pH adjuster.
An adjusting agent, an antifoaming agent and the like can be used in combination. Water is contained in the solution in an amount of about 5 to 95% by weight.

(Liquid Containing Adhesive Material) Next, a liquid containing an adhesive material will be described as a latent image forming liquid in the present invention. The adhesive material here refers to a substance having adhesiveness at normal temperature or when heated, and mainly includes an organic polymer. Specifically, acrylic acid,
Homopolymers and copolymers of acrylic monomers such as methacrylic acid, acrylic esters and methacrylic esters, and vinyl monomers such as polyvinyl acetate, polystyrene, polyvinyl pyrrolidone, polyvinyl butyral, polyvinyl alcohol, polyvinyl chloride, etc. homopolymer and ethylene - vinyl acetate copolymers thereof, polyesters, condensation polymers such as polyamides, styrene - butadiene copolymer, acrylonitrile - be mentioned rubber-based polymers such as butadiene copolymers it can. Among these, the glass transition point (Tg)
Is preferably lower than 90 ° C. Further, these may be an emulsion dispersion in water, that is, a so-called latex state.

The liquid containing the adhesive material refers to a solution obtained by dissolving or dispersing the above-mentioned adhesive material in water or a solvent such as an organic solvent (including solid dispersion and emulsified dispersion).
The organic solvents referred to herein include, specifically, methyl alcohol, ethyl alcohol, n-propyl alcohol, i
Amides such as alkyl alcohols of propyl alcohol, dimethylformamide, dimethylacetamide, etc., ethylene glycol, 1,2,6 hexanetriol, thiodiglycol, propylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, glycerin Monohydric or polyhydric alcohols such as dioxane, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, triethylene glycol monobutyl ether, tripropylene glycol monomethyl ether, etc., acetone, methyl ethyl ketone, diacetone alcohol And keto alcohols and the like.

These water or organic solvents may be used alone or in combination of a plurality of solvents to dissolve or disperse the adhesive material. In addition, the above solution is used in combination with a surface tension adjusting material, an antifungal agent, a viscosity adjusting material, a pH adjusting material, a defoaming material, a plasticizer, etc. in order to improve discharge suitability, liquid storage stability, and adhesive properties. can do.

When the latent image forming liquid of the present invention contains the tacky material in a dispersed form (solid dispersion or emulsified dispersion), the compound represented by the formula (I) R- (SP) n Is preferably added. By adding this compound,
The tacky material in the dispersed form does not cause aggregation, the latent image forming liquid is stably held, and the occurrence of nozzle clogging is also prevented. The compound represented by formula (I) is added in an amount of 3 to 20% by mass, preferably 3 to 10% by mass, based on the solid content of the latent image forming solution.

In the formula (I), R represents a hydrophobic group or a hydrophobic polymer, and P contains at least one of the following structural units A, B and C, and has a polymerization degree of 10 to 3500. Represents coalescence. n represents 1 or 2.

[0034]

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Here, R ¹ represents -H or an alkyl group having 1 to 6 carbon atoms, R ² represents -H or an alkyl group having 1 to 10 carbon atoms, and R ³ represents -H or -CH ₃ . And R
⁴ H, -CH _3, (including ammonium salt or metallic salt) -CH ₂ COOH or represents -CN, X is -H, -C
OOH (including ammonium or metal salts) or -CO
Represents NH _2, Y is (including ammonium salt or metallic salt) -COOH, - (including ammonium salt or metallic _{salt) SO 3 H, - OSO 3} H ( including ammonium salt or metallic salt), - CH ₂ SO ₃ (including ammonium salt or metallic _{salt) H, - CONHC (CH 3} ) ( including ammonium salt or metallic salt) ₂ CH ₂ SO ₃ H or -CONHCH ₂ C
Represents H ₂ CH ₂ N ⁺ (CH ₃ ) ₃ Cl ⁻ .

In the general formula (I), R ¹ is preferably -H, and R ² is preferably -CH ₃ . Typical examples of the compound represented by the general formula (I) include a random or block copolymer of vinyl alcohol and a vinyl ester or a vinyl alcohol containing a third monomer component having an anionic group such as a carboxyl group. And random or block copolymers of vinyl and vinyl esters whose terminals are modified with an alkyl group or a hydrophobic polymer.

The hydrophobic group represented by R in the general formula (I) includes an aliphatic group (eg, an alkyl group, an alkenyl group,
Alkynyl group, etc.), aromatic groups (eg, phenyl group, naphthyl group, etc.) and alicyclic groups, including those substituted. Examples of the substituent include an aliphatic group, an aromatic group, an alicyclic group, a heterocyclic group, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an N-substituted sulfamoyl group, a carbamoyl group, an acylamino group, an alkylsulfonylamino group,
Examples include an arylsulfonylamino group, an alkoxy group, an aryloxy group, an aralkyl group, and an acyl group.

When the hydrophobic group of R in the general formula (I) is an alkyl group, it has 3 to 70 carbon atoms, preferably 4 to 5 carbon atoms.
0, especially 8 to 24 is preferred. A specific example when R is a hydrophobic group is described in paragraph 0034 of JP-A-10-95942.
To (S-1) to (S-
Groups up to 50) are preferred.

When R in the general formula (I) is a hydrophobic polymer, polystyrene and its derivatives, polymethacrylate (eg, polymethyl methacrylate) and its derivatives, polyarylic acid esters and its derivatives,
Water-insoluble vinyl polymers and vinyl copolymers represented by polybutene, polyvinyl acetate, polyvinyl versatate, etc., water-insoluble polyoxyalkylenes such as polyoxypropylene and polyoxytetramethylene, and furthermore Water-insoluble polymers such as polyamide and polyester are exemplified. In particular, polystyrene and its derivatives, polymethacrylate and its derivatives, polyacrylate and its derivatives, and polyvinyl chloride are preferably used. The degree of polymerization of the hydrophobic polymer is 2 or more and 50 or more.
It is 0 or less, preferably 2 or more and 200 or less, and more preferably 2 or more and 100 or less.

The polymer P in the compound represented by the general formula (I) is a polymer containing at least one of the above structural units A, B and C. As Specifically structural units A constituting the polymer A, vinyl alcohol, alpha-
Methyl vinyl alcohol, α-propyl vinyl alcohol and the like can be mentioned. Examples of the structural unit B constituting the polymer P include vinyl acetate, vinyl formate, vinyl propionate, and their α-substituted products. Further, as the structural unit C constituting the polymer P, acrylic acid, methacrylic acid or crotonic acid (each including an ammonium salt or a metal salt such as Na or K), maleic acid or itaconic acid (a monoalkyl ester or an ammonium salt, respectively) Or Na, K
Etc.), vinylphosphonic acid, vinylsulfuric acid,
Acrylic sulfonic acid, methacrylsulfonic acid, 2-acrylamido-3-methylpropanesulfonic acid or 2-methacrylamido-3-methylpropanesulfonic acid (including an ammonium salt or a metal salt such as Na or K, respectively), acrylamidopropyltrimethyl Monomer units that ion dissociate in water, such as ammonium chloride or methacrylamidopropyltrimethylammonium chloride. Particularly, itaconic acid and maleic acid are preferred.

Among them, the structural unit A includes a vinyl alcohol unit, the structural unit B includes a vinyl acetate unit, and the structural unit C includes a carboxylic acid (an ammonium salt or a metal salt such as Na or K). ) Containing vinyl monomer units or sulfonic acids (ammonium salts, or Na,
(Including metal salts such as K) is a more preferred unit.

The content of the structural units A, B, and C constituting the polymer P is not particularly limited. However, when the contents of A, B, and C are x, y, and z mol%, respectively, x + y + z
= 100, 0 ≦ x ≦ 100, 0 ≦ y ≦ 75, 0 ≦ z ≦ 1
00 is preferable, x + y + z = 100, 0 ≦ x ≦ 10
0, 0 ≦ y ≦ 50 and 0 ≦ z ≦ 50 are particularly preferred. Further, when the content of the structural unit C is 1 mol% or less, the content of the structural unit A is 50 mol% to 100 in order that the polymer represented by the general formula (P) is water-soluble or water-dispersible. Mol%
It is preferred that

The compounds represented by the general formula (I) of the present invention include those in a wide range from water-soluble to water-dispersible. As long as the compound represented by the general formula (I) of the present invention is water-soluble or water-dispersible, the polymer P is composed of the above structural units A and B
And may include structural units other than C,
As these structural units, such as ethylene, propylene, Isoputen, acrylonitrile, acrylamide,
Examples include methacrylamide, N-vinylpyrrolidone, vinyl chloride or vinyl fluoride units. The polymerization degree of the polymer P is 10 to 3500, preferably 10 to 2000, more preferably 10 to 1000, and particularly preferably 10 to 50.
0.

R in the structural units A and B of the polymer P
^As the alkyl group for ¹ and R ^2, a methyl group is particularly preferred. Further, the alkyl group is a hydroxyl group, an amide group, a carboxyl group, a sulfonic acid group, a sulfinic acid group,
It may be substituted by a sulfonamide group or the like.

The compounds represented by the general formula (I) of the present invention vary in the optimum chemical composition and molecular weight of P and R constituting the compounds according to the purpose of the present invention. The composition having a weight ratio of 0.001 ≦ R / P ≦ 2, more preferably 0.01 ≦ R / P ≦ 1, is particularly effective.

Next, the image transfer material and the image receiving sheet used in the method of the present invention will be described. The image transfer material of the present invention is obtained by providing a transfer recording layer made of a thermal transfer material on a support. Hereinafter, the support constituting the image transfer material, the transfer recording layer, and other optional layers will be described in detail.

[Support] The material of the support of the image transfer material is not particularly limited, and various support materials can be used according to the purpose. Preferred examples of the support material include:
Polyethylene terephthalate, polyethylene-2,6-
Examples include synthetic resin materials such as naphthalate, polycarbonate, polyethylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and styrene-acrylonitrile copolymer. Among them, biaxially stretched polyethylene terephthalate is preferable in consideration of mechanical strength and dimensional stability against heat.

The support may be subjected to a surface roughening treatment and / or the provision of one or more undercoat layers in order to improve the adhesion to the transfer recording layer provided thereon. preferable. Examples of the surface roughening treatment include a glow discharge treatment and a corona discharge treatment. The material of the undercoat layer preferably has high adhesiveness to both surfaces of the support and the transfer recording layer, low thermal conductivity, and excellent heat resistance. Examples of such a material for the undercoat layer include styrene, styrene-butadiene copolymer, and gelatin. The thickness of the entire undercoat layer is usually 0.01 to 2 μm. Also, on the surface of the thermal transfer sheet opposite to the side where the transfer recording layer is provided,
If necessary, various functional layers such as a release layer or the like, or a surface treatment can be performed.

[Transfer Recording Layer] The transfer recording layer, when forming a colored image, contains at least a pigment which is transferred to an image receiving sheet to form a colored image, and a binder for forming a layer. Contains resin and, if desired, other components. The transfer recording layer in the present invention is not necessarily limited to the recording layer of colored, for example, may be an colorless resin layer when used in the formation of such a lithographic printing plate, the liquid transfer property described above It is necessary that the accelerating material has a property of improving transferability. Pigments are generally classified into organic pigments and inorganic pigments.The former has properties such as excellent transparency of the coating film, and the latter generally has properties such as excellent concealing properties, and can be appropriately selected according to the application. I just need. When the image transfer material according to the present invention is used as a color proof for printing color proofing, organic pigments that match yellow, magenta, cyan, and black commonly used in printing inks or have a similar color tone are preferably used. used. In addition, a metal powder, a fluorescent pigment, or the like may be used. Examples of preferably used pigments include azo pigments, phthalocyanine pigments, anthraquinone pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, and nitro pigments. The pigment used for the transfer recording layer is divided by hue,
These are listed below, but are not limited thereto.

1) Yellow pigments Hansa Yellow G, Hansa Yellow 5G, Hansa Yellow 10G, Hansa Yellow A, Pigment Yellow L,
Permanent Yellow NCG, Permanent Yellow F
GL, permanent yellow HR. 2) red pigment permanent red 4R, permanent red F2R,
Permanent Red FRL, Lake Red C, Lake Red D, Pigment Scarlet 3B, Bordeaux 5B,
Alizarin Lake, Rhodamine Lake B. 3) blue pigment phthalocyanine blue, Victoria Blue Lake, Fast Sky Blue. 4) Black pigment carbon black.

As the binder resin for the transfer recording layer, an amorphous organic high molecular polymer having a softening point of 40 ° C. to 150 ° C. is preferable. Examples of the amorphous organic high-molecular polymer include butyral resin, polyamide resin, polyethyleneimine resin, sulfonamide resin, polyester polyol resin, petroleum resin, styrene, vinyltoluene, α-methylstyrene, 2-methylstyrene, and chloroform. Styrene such as styrene, vinylbenzoic acid, sodium vinylbenzenesulfonate and aminostyrene and derivatives thereof, homopolymers and copolymers of substituted products, methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and hydroxyethyl methacrylate And methacrylic acid, methyl acrylate, ethyl acrylate,
Acrylates such as butyl acrylate and α-ethylhexyl acrylate, and dienes such as acrylic acid, butadiene and isoprene, acrylonitrile, vinyl ethers, maleic acid and maleic esters, maleic anhydride, cinnamic acid, vinyl chloride, and vinyl acetate it can be used a copolymer of a monomer such as alone or other vinyl monomer and the like. These resins can be used as a mixture of two or more kinds.

The transfer recording layer preferably contains 30 to 70% by weight of a pigment, more preferably 30 to 50% by weight. The transfer recording layer is made of a resin of 70%.
The content is preferably from 30 to 30% by weight, more preferably from 70 to 50% by weight.

When a multicolor image is produced by repeatedly superimposing a number of image layers (transfer recording layers on which images are formed) on the same image receiving sheet, transfer is performed to enhance the adhesion between the images. The recording layer preferably contains a plasticizer. Examples of such plasticizers include dibutyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate,
Phthalic acid esters such as dinonyl phthalate, dilauryl phthalate, butyl lauryl phthalate, and butyl benzyl phthalate; aliphatic dibasic acid esters such as di (2-ethylhexyl) adipate and di (2-ethylhexyl) sebacate; Examples include phosphoric acid triesters such as tricresyl phosphate and tri (2-ethylhexyl) phosphate, polyol polyesters such as polyethylene glycol ester, and epoxy compounds such as epoxy fatty acid ester. In addition to the general plasticizers described above, polyethylene glycol dimethacrylate, 1,2,4-butanetriol trimethacrylate, trimethylolethane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol Acrylic esters such as polyacrylates are also preferably used in combination depending on the type of binder used. Incidentally, two or more plasticizers may be used in combination.

In the transfer recording layer, the weight ratio of the total amount of the pigment and the resin to the plasticizer is generally 1%.
00: 1 to 100: 3, preferably 100: 1.5 to 1
00: 2. A surfactant, a thickener, and the like are further added to the transfer recording layer as needed.

The transfer recording layer is provided by preparing a coating solution in which a pigment and the binder resin or the like are dissolved or dispersed, applying the coating solution on a support (on the support, on the undercoat layer), and drying. be able to. Examples of the solvent used for preparing the coating liquid include n-propyl alcohol, methyl ethyl ketone, propylene glycol monomethyl ether (MFG), and methanol. Coating and drying can be performed by using ordinary coating and drying methods. Incidentally, the layer thickness (dry layer thickness) of the transfer recording layer is 0.1-5.
0 μm, preferably 0.3 to 3.0 μm.

A transfer-promoting material is applied imagewise to the surface of a transfer recording layer of an image transfer material having a structure in which a transfer recording layer is laminated on a support in this order, or to the surface of an image receiving sheet described later. When an image is formed, of the thermal transfer material constituting the transfer recording layer, the transfer promoting material permeates the transfer recording layer only in the portion of the latent image to which the transfer promoting material has adhered, and the binding of the binder constituting the layer is loosened. At the same time, the bonding force between the support and the image forming layer is reduced, the transferability to the image receiving sheet is improved, and the transfer can be performed at a lower temperature.

[Image-Receiving Sheet] The image-receiving sheet which can be used in the method of the present invention is usually provided with a support and thereon an image-receiving layer containing one or more binder resins. Cushion layer, release layer, between layers
And a structure in which one or two or more intermediate layers are provided. However, if the affinity with the above-mentioned transfer recording layer is good, polyethylene terephthalate (P
A resin sheet such as ET), plain paper, coated paper, glass epoxy sheet, and metal plate can also be used. In the case of an image receiving sheet having an image receiving layer provided on a support, a back layer for improving transportability is preferably provided on the surface of the support opposite to the image receiving layer.

Examples of the support include ordinary sheet-like base materials such as plastic sheets, metal sheets, glass sheets, and paper. Examples of the plastic sheet include a polyethylene terephthalate sheet, a polycarbonate sheet, a polyethylene sheet, a polyvinyl chloride sheet, a polyvinylidene chloride sheet, a polystyrene sheet, a styrene-acrylonitrile sheet, and a polyester sheet. In addition, printing paper, coated paper, or the like can be used as the paper support.

It is preferable that the support has minute voids (voids) since curling can be prevented and image quality can be improved. Such a support is, for example, a thermoplastic resin, a mixed melt obtained by mixing an inorganic pigment or a filler made of an incompatible polymer with the thermoplastic resin, a single-layer or multi-layer by a melt extruder. It can be produced by forming a film and stretching it uniaxially or biaxially.
In this case, the porosity is determined by the selection of the resin and the filler, the mixing ratio, the stretching conditions, and the like.

As the thermoplastic resin, a polyolefin resin such as polypropylene and a polyethylene terephthalate resin are preferable because of good crystallinity, good stretchability and easy void formation. It is preferable to use the above-mentioned polyolefin resin or polyethylene terephthalate resin as a main component, and appropriately use a small amount of another thermoplastic resin in combination. As the inorganic pigment used as the filler, those having an average particle size of 1 μm or more and 20 μm or less are preferable, and calcium carbonate, clay, diatomaceous earth, titanium oxide, aluminum hydroxide, silica and the like can be used. When polypropylene is used as the thermoplastic resin as the incompatible resin used as the filler, it is preferable to combine polyethylene terephthalate as the filler. The content of the filler such as an inorganic pigment in the support is generally about 2 to 30% by volume.

The thickness of the support of the image receiving sheet is usually from 10 to
It is 400 μm, preferably 25 to 200 μm. Further, the surface of the support is subjected to a surface treatment such as a corona discharge treatment or a glow discharge treatment in order to enhance the adhesion with the image receiving layer (or the cushion layer) or the adhesion with the image forming layer of the thermal transfer sheet. May be.

In order to transfer the image forming layer on the surface of the image receiving sheet and fix it, it is preferable to provide one or more image receiving layers on the support. The image receiving layer is preferably a layer formed mainly of a binder resin composed of an organic polymer. The binder resin is preferably a thermoplastic resin, for example, acrylic acid, methacrylic acid, acrylic acid ester, homopolymers of acrylic monomers such as methacrylic acid esters and copolymers thereof,
Methylcellulose, ethylcellulose, cellulosic polymers such as cellulose acetate, polystyrene,
Homopolymers and copolymers of vinyl monomers such as polyvinylpyrrolidone, polyvinylbutyral, polyvinyl alcohol, polyvinyl chloride and the like, condensation polymers such as polyester and polyamide, and rubbers such as butadiene-styrene copolymer System polymer. The binder of the image receiving layer is provided with a glass transition temperature (Tg) in order to obtain a proper adhesive strength with the image forming layer.
Is preferably a polymer having a temperature lower than 90 ° C. For this purpose, it is also possible to add a plasticizer to the image receiving layer.
Further, the binder polymer preferably has a Tg of 30 ° C. or higher in order to prevent blocking between sheets. As the binder polymer of the image receiving layer, a polymer that is the same as or similar to the binder polymer of the image forming layer may be used in terms of improving adhesion to the image forming layer during transfer recording and improving sensitivity and image strength. Particularly preferred. Since the image receiving layer is a layer formed by applying an organic solvent solution or an aqueous solution (aqueous solution, aqueous dispersion) containing a binder resin on the support, it is different from a support such as a plastic sheet in promoting thermal transfer. Receptive to materials. Receptivity means that the image receiving layer is plasticized or swelled by the thermal transfer promoting material, for example. The plasticizing or swelling action, the transfer temperature of the thermal transfer material may be reduced. According to the method of the present invention, an image can be once formed on an image receiving layer and then retransferred to a printing paper or the like.

The thickness of the image receiving layer is 0.3 to 7 μm, preferably 0.7 to 4 μm. When the thickness is 0.3 μm or less, the film strength is insufficient at the time of retransfer to the printing paper, and the film is easily broken. If the thickness is too large, the gloss of the image after the re-transfer of the paper increases, and the closeness to the printed matter decreases. The image forming method of the present invention is performed using the above-described image transfer material, image receiving sheet and transferability promoting material.

Next, an image forming apparatus according to the present invention will be described with reference to the drawings, and an image forming method will be sequentially described for each process. FIG. 2 is a conceptual diagram showing a configuration of the image forming apparatus according to the present invention. In the image forming apparatus 1, a discharge head (nozzle head) 13 for applying a droplet-like transferability promoting material to the image transfer material 5 and the image transfer material 5 and the image receiving sheet 11 are brought into close contact with each other to perform transfer. A pair of pressure rollers including a support drum 3 and a pinch roller 7 having a heating unit are provided. An image transfer material (transfer sheet) 5 having a transfer recording layer formed on a support is supported on the support drum 3 so as to be wound around a part of the outer periphery. The transfer recording layer formed on the support contains materials such as pigment-based dyes and metal particles, and a binder resin and the like. In this embodiment, the case the transfer material is a pigment-based dye as an example.

The image transfer material 5 has a support drum 3 on the support side.
, And is supported by the support drum 3 such that the transfer recording layer side becomes the surface. In the image forming apparatus 1, a pinch roller 7 in the same axial direction as the support drum 3 is disposed to face.
A heater whose temperature can be controlled is built in the pinch roller 7. An image receiving sheet 11 is inserted between the support drum 3 and the pinch roller 7. Between the support drum 3 and the pinch roller 7, an image transfer material 5 and an image receiving body 1 are provided.
1 are laminated so that the transfer recording layer and the image receiving surface of the image receiving sheet 11 are in close contact with each other, inserted between the pressure rollers, and heated while rotating the support drum 3 and the pinch roller 7 in the right direction in the figure. To move to.
In this embodiment, an example in which the image receiving sheet uses a PET film as a support will be described.

The transfer temperature of the portion where the latent image is formed with the transferability promoting material is lower than that of the peripheral portion of the transfer recording layer. Therefore, the heating condition of the pinch roller 7 at this time is such that the temperature of the contact portion between the latent image forming portion and the image receiving layer is lower than the original transfer temperature of the transfer recording layer and higher than the transfer temperature of the latent image portion. If the temperature range is set in the range, the latent image forming part and the non-forming part (part where the transferability promoting material does not adhere)
Image transfer with clear on / off of the image can be performed. The heating temperature is lower than the transfer temperature of the transfer recording layer, and
The temperature is preferably in a range exceeding the transfer temperature of the latent image portion.

The image forming apparatus 1 is provided with a droplet discharge head 13 facing the support drum 3. Droplet discharge head 1
3 does not substantially move and has a plurality of nozzle groups.
The droplet discharge head 13 discharges a droplet made of a liquid transferability-promoting material in an image-like manner, and forms a latent image on the surface of the image transfer layer of the image transfer material 5 supported by the support drum 3. As the structure of the droplet discharge head 13, a structure having a structure based on a known general ink jet discharge principle can be applied.

When a multicolor image is formed using this apparatus, black (K), cyan (C), magenta (M), and yellow (Y) are used as color materials contained in the transfer recording layer of the image transfer material. An image is formed with an image transfer material using each color of ()). A droplet of the transferability promoting material is ejected imagewise from the droplet ejection head 13 onto the K color image transfer material 5 to form a latent image on the transfer recording layer of the image transfer material 5. In this case, the transfer recording layer is stationary with respect to the droplet discharge head. This step is a latent image forming step.

Next, the transfer recording layer of the image transfer material 5 on which the latent image is formed and the image receiving surface of the image receiving sheet 11 are laminated so as to be in close contact with each other, and are pressed by the support drum 3 and the pinch roller 7. At this time, the entire surface of the image receiving sheet 11 and the image transfer material 5 is heated under a predetermined condition by controlling the heating means inside the pinch roller 7, so that only the latent image portion on which the transferability accelerating material adheres like an image. The image is transferred imagewise onto the transfer sheet 11 surface. That is, a transfer step. Thereafter, the image transfer material 5 is rolled in the circumferential direction along the support drum 3 and transported, whereby the image transfer material 5 is peeled off from the image receiving sheet 11, and a black image is formed on the surface of the image receiving sheet 11. You.
Hereinafter, the transfer recording layer for each color is sequentially transferred and fixed on the same image receiving sheet 11 based on the image information using the image transfer materials 5 of C, M, and Y colors in the same procedure. To form a full-color image in which four colors are superimposed.

As described above, according to the image forming method using the above-described image forming apparatus 1, the entire surface of the image transfer material 5 and the image receiving sheet 11 is heated so that the latent image to which the transferability promoting material adheres is obtained. The transferability of only the portion is improved, and only the latent image portion is selectively transferred to the transfer sheet 11 and fixed.
Unlike the conventional peeling transfer method, it is possible to form a uniform image without unevenness in thermal conductivity due to unevenness in resistance value of the thermal head, unevenness in contact, and unevenness in thickness of the support.

Further, since pigment-based dyes can be used in the transfer recording layer, there is no need to select pigments or dyes due to physical property limitations as in the case of ink jet recording inks. Can be selected, desired hue can be selected and excellent hue reproducibility, and pigments excellent in light resistance, metal pigments, functional pigments and the like can be arbitrarily selected, so that an image having good durability and a desired image can be obtained. An image having a hue and a function can be formed. Therefore, the present invention can be suitably applied to a color proof or the like in which hue reproducibility is important.

Next, another embodiment of the image forming apparatus of the present invention will be described. FIG. 3 shows a second configuration of the image forming apparatus according to the present invention. The image forming apparatus 20 includes the image receiving sheet 11
Discharge head 2 for applying droplet-like transferability promoting material to the surface
1, the image transfer material 5 and the image receiving sheet 11 are brought into close contact with each other,
A pair of pressure rollers consisting of the pinch roller 7 for having a supporting drum 3 and the heating means for performing transfer, adhesion, and receiving the image transfer material 5 which has finished the transfer process sheet 1
And a peeling bar 23 for peeling off the base material 1.

In the image forming apparatus 20 according to this embodiment, the image transfer material 5 is provided downstream of the support drum 3 in the transport direction.
Bar (peeling bar) that presses the sheet toward the image receiving sheet 11 side
23 are provided. Further, between the peeling bar 23 and the winding means 25 of the image transfer material 5, the image transfer material 5 is wound with a predetermined tension. Further, the image transfer material 5 after passing through the peeling bar 23 is peeled at an angle close to a right angle with respect to the image receiving sheet 11. According to the image forming apparatus 20 configured as described above,
Since the support of the image transfer material 5 is bent at an angle close to a right angle with the separation bar 23 as a boundary, the separation between the support and the transfer material is promoted by the difference in bending radius, and the surface of the image receiving sheet 11 is Of the transfer recording layer can be improved.

The image forming apparatus 20 has a droplet discharge head 21 facing the support drum 3. The droplet discharge head 21 is substantially fixed to the image receiving sheet 11 at the time of droplet discharge. In this embodiment, except that the ejection head 21 ejects droplets in the direction of the image receiving sheet 11 and that the ejection head 21 is provided with a peeling bar 23 for stably peeling the image transfer material 5 and the image receiving sheet 11 from each other, It has a configuration similar to that of the image forming apparatus 1. The droplet discharge head 21 discharges droplets of the transferability promoting material imagewise onto the surface of the image receiving sheet 11 to form a latent image, and the image receiving sheet 11 is supported by the image transfer material supported by the support drum 3. 5 has a function of improving the transferability of the transfer recording layer at the portion where the latent image is formed, in close contact with the surface of the transfer recording layer.

In this embodiment, since the transferability promoting material is discharged to the image receiving sheet 11 instead of to the transfer recording layer, even when a thin transfer recording material is used, a decrease in the positional accuracy of the latent image due to the discharge factor can be suppressed. Can be. As described above, in the image forming method of the present invention, an image-like latent image is formed with the transferability-promoting material, and the transfer recording layer itself in that portion is transferred and fixed to the image receiving sheet 11 to form an image. As compared with an image formed by discharging ink, there is no fear of ink bleeding, and an image excellent in resolution and hue reproducibility can be formed. Further, as described above, the same effect is obtained when the latent image formed of the transferability promoting material is formed on the surface of the transfer recording layer of the image transfer material 5 or on the image receiving surface of the image receiving sheet.

Hereinafter, a modified example of the image forming apparatus of the present invention will be described. In the image forming apparatus 30 according to the present invention, as shown in FIG. 4, the droplet discharge direction of the droplet discharge head is the same as that of the image transfer material 5 and the image receiving sheet 1.
The discharge direction is provided so as to be switchable so that the discharge direction can be set to any one of the directions (1), and the discharge direction is appropriately changed depending on the material and the transfer conditions. As a direction switching structure of the droplet discharge head 31, a droplet discharge head 31 having a single or a plurality of discharge holes is provided in a rotatable manner (shown in FIG. 4), or in advance in each direction. It is conceivable that a discharge hole is provided and one of the discharge holes is opened and closed as required. According to the image forming apparatus 30, the droplet discharge direction of the droplet discharge head 31 can be adjusted with respect to any suitable image forming surface based on the suitability of the image transfer material 5 or the image receiving sheet 11 to be used and the droplets. By switching, a latent image can be formed.

Further, in the image forming method of the present invention, it is preferable to add a step of heating and drying the image receiving surface of the image receiving sheet after the transfer step. This drying step evaporates the residual solution for forming the latent image. As a result, when an image transfer material of another color is further transferred and transferred onto the image receiving sheet, there is no secondary color fog and high image quality is obtained. Can be produced. As an image forming apparatus for performing the above method, there is an image forming apparatus provided with the heating / drying apparatus shown in FIGS. Image forming apparatus 4 shown in FIG.
In the image forming apparatus 50 shown in FIG. 2, a heating / drying device 27 is further provided downstream of the transfer position in the image forming apparatus shown in FIG. 2, and in the image forming apparatus 50 shown in FIG. In the image forming apparatus indicated by
The heating and drying device 27 is provided on the downstream side.
Although not shown, it is preferable to heat-dry the applied surface after transferring the transferability-promoting material to the image transfer material or the image receiving sheet before transferring the image so as not to lower the resolution. .

Further, as an application of the image forming method of the present invention, a drum-shaped plate having an outer peripheral surface as a plate surface instead of the image receiving sheet 11 using an image transfer material 5 having a lipophilic resin layer formed on a support. By performing image formation using the cylinder in the same procedure, a desired fine image can be formed on a curved surface such as the outer peripheral surface of the plate cylinder. A set plate cylinder can be formed.

According to this image forming apparatus, since droplets are ejected in a planar manner, high-speed image formation can be accurately performed.

[0080]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In this example, unless otherwise specified.
“Parts” indicates “parts by mass”, and “%” indicates “% by mass”. Example 1 <Preparation of image transfer material> Preparation of transfer recording layer coating solution Butyral resin 12.0 parts (Esrec FPD-1 manufactured by Sekisui Chemical Co., Ltd.) Magenta pigment 12.0 parts (Toyo Ink Co., Ltd. Rio) Nourlet LX-235) n-propyl alcohol 110.4 parts Dispersing aid 0.8 part (Solsperse S-20000 manufactured by ICI Corporation)

[0081] 0.24 parts of stearamide and n-
60 parts of propyl alcohol was added to prepare a diluting solution, which was coated on a 5 μm-thick polyester film support having a release treatment on the back surface so as to have a dry film thickness of 0.38 μm to form a transfer recording layer, and image transfer was performed. The material was obtained.

<Preparation of Image Receiving Sheet> “Coating Solution for First Layer” Vinyl chloride-vinyl acetate copolymer 160 parts (Solvain CL2 manufactured by Nissin Chemical Co., Ltd.) Ethylene-vinyl acetate copolymer 61 parts (Mitsui Di 28 parts of sebacic acid polyester (FN-G25 manufactured by Nippon Soda Co., Ltd.) 4 parts of perfluoroalkyl group-containing oligomer (Mega Fac F-178K manufactured by Dainippon Ink and Chemicals, Inc.) Ethyl ketone 630 parts Toluene 210 parts Dimethylformamide 30 parts

“Second Layer Coating Solution” Polyvinyl butyral resin 16 parts (Denka Butyral # 2000-L, manufactured by Denki Kagaku Kogyo KK) N, N-dimethylacrylamide-butyl acrylate copolymer 4 parts Perfluoroalkyl group-containing Oligomer 0.5 part (Mega Fac F-177 manufactured by Dainippon Ink and Chemicals, Inc.) 200 parts of n-propyl alcohol

The above first layer coating solution was applied on a PET film support having a thickness of 130 μm using a spin coating machine,
The film thickness after drying at 100 ° C. was adjusted to 20 μm. Using a spin coater, apply the second layer coating solution on the first layer coating layer, and dry at 100 ° C. to adjust the thickness of the second layer to 2 μm. Produced.

<Preparation of Transferability-Promoting Material Liquid 1> Distilled Water 50 parts n-Propyl alcohol 45 parts Polyoxyethylene (4) lauryl ether 5 parts

As the image forming apparatus, the same image forming apparatus 1 as shown in FIG. 2 was used. The ejection head used was a rectangular head similar to that shown in FIG. 1 and had a size of 34 mm in length and 51 mm in width. The diameter of the hole of each nozzle was 20 μm, and the pitch between the nozzles (the distance between the centers of two adjacent nozzles) was 170 μm in both the vertical and horizontal directions. As shown in FIG. 2, the image transfer material 5 is sandwiched and passed between the support drum 3 and the pinch roller 7 with the surface of the transfer recording layer of the image transfer material 5 facing down and the image receiving surface of the image receiving sheet 11 facing up.

At this time, the transferability promoting material solution 1 (surface tension: 25.6 mN / m, viscosity:
2.0 mPa. s) was jetted imagewise onto the transfer recording layer surface of the image transfer material 5 to form a latent image. After the transfer body and the image receiving body are peeled off after passing through a pressure roller with the surface temperature of the pinch roller set to 75 ° C., the transfer recording layer is transferred onto the image receiving surface corresponding to the latent image forming portion, and the image is formed. Was formed. The image forming speed was extremely high, and the obtained image was uniform, had no color unevenness, had good hue reproducibility, was high-definition, and showed no wrinkles or distortion of the image receiving sheet. This device (set the surface temperature of the pinch roller to 75 ° C)
Then, when the image was transferred through the image transfer material and the image receiving sheet, the temperature of the transfer portion (measured with a sensor interposed between the image transfer material and the image receiving sheet) was 61 ° C. In addition, in order to investigate the transferable temperature of the transfer section when the transferability-enhancing material solution is applied and when it is not applied, the surface temperature of the pinch roller of the present apparatus was varied and the transferable temperature was determined. Is
The temperature was 47 ° C. when the liquid was attached, and 76 ° C. when the liquid was not attached.

Example 2 An image was formed in the same manner as in Example 1 except that the latent image forming liquid was changed as follows. <Latent image forming liquid> Distilled water 65 parts Ethylene-vinyl acetate copolymer latex (solid content 50%) 35 parts As in Example 1, a good image was obtained at high speed.

[0089]

As described above, according to the image forming method of the present invention, the latent image forming liquid is applied imagewise to the image transfer recording material to form a latent image, and only the latent image forming portion is formed. Is transferred to the surface of the image receiving sheet by peeling, so that the range of choices of image transfer materials can be greatly expanded, images with good hue reproducibility can be formed, and images can be formed with light-resistant pigments, functional inorganic materials, etc. Can also be adapted. Further, unlike the conventional transfer method, there is no influence of the temperature distribution caused by the thickness unevenness of the support, the unevenness of contact with the thermal head, and the unevenness of heat diffusion, so that an image can be formed uniformly and without color unevenness. . Further, the image forming method of the present invention has an effect that the transfer temperature is lowered and the support of the image receiving sheet is less damaged. Further, in addition to these effects, the present invention, when a latent image is formed by discharging the latent image forming liquid from a plurality of nozzles onto a transfer recording layer surface or an image receiving surface in an imagewise manner, the plurality of nozzles are transferred to the transfer recording layer. Since the latent image forming liquid is ejected simultaneously or sequentially from a plurality of nozzles without being substantially moved with respect to the surface or the image receiving surface, high-speed image formation is possible and the accuracy of the landing position of the droplet is improved. Therefore, a high-definition image can be obtained. Further, it is relatively easy to manufacture a nozzle head used in the image forming method of the present invention.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating an example of a nozzle head provided with a plurality of nozzles used in an image forming method of the present invention.

FIG. 2 is a conceptual diagram illustrating one embodiment of an image forming apparatus according to the present invention.

FIG. 3 is a conceptual diagram illustrating an aspect in which an ejection head of the image forming apparatus according to the present invention is arranged in a direction of an image receiving sheet.

FIG. 4 is a conceptual diagram showing a mode in which the direction of a discharge head of the image forming apparatus according to the present invention is switchably arranged.

FIG. 5 is a conceptual diagram illustrating one embodiment of an image forming apparatus in which a heating and drying device is provided in the image forming apparatus of FIG. 2;

6 is a conceptual diagram illustrating one embodiment of an image forming apparatus in which a heating and drying device is provided in the image forming apparatus of FIG.

[Explanation of symbols]

1, 20, 30, 40, 50 Image forming apparatus 3 Support drum 5 Image transfer material 7 Pinch roller 10 Nozzle 11 Image receiving sheet 13, 13A, 21, 31 Droplet discharge head (nozzle head) 23 Peeling member (peeling bar) 27 Heat drying equipment

Claims (6)

[Claims] 1. A transfer temperature of a thermal transfer material to either a surface of a transfer recording layer of an image transfer material having a transfer recording layer made of a thermal transfer material on a support or an image receiving surface of an image receiving sheet having an image receiving layer containing a binder resin. Latent image forming step of forming a latent image by ejecting a latent image forming liquid containing a transferability promoting material or a tacky material capable of reducing image quality from a plurality of nozzles in an imagewise manner, and a transfer recording layer surface of the image transfer material And heating the image-receiving sheet in close contact with the image-receiving sheet, and a transfer step of transferring a transfer recording layer corresponding to the latent image onto the image-receiving sheet, the image forming method comprising: An image forming method, wherein the latent image forming liquid is discharged from a plurality of nozzles simultaneously or sequentially without substantially moving with respect to an image receiving surface. 2. The image forming method according to claim 1, wherein the plurality of nozzles form a plurality of groups and are sequentially driven in units of the groups. 3. The latent image forming liquid is discharged to a position different from a discharge position before the movement on the surface of the transfer recording layer or the image receiving surface by finely moving the nozzle in one or more directions. The image forming method according to claim 1. 4. The image forming method according to claim 1, wherein the minute movement is smaller than a nozzle pitch. 5. The method according to claim 1, wherein the nozzle is minutely moved in one or more directions, and the latent image forming liquid is ejected to the transfer recording layer surface or the image receiving surface at substantially the same place as the ejection place before the movement. The image forming method according to claim 1. 6. A transfer recording layer of an image transfer material comprising a transfer recording layer made of a thermal transfer material provided on a support,
An image forming apparatus for transferring to an image receiving sheet having a binder resin-containing image receiving layer, comprising: a transferability-enhancing material or an adhesive capable of lowering the transfer temperature of a thermal transfer material to either the surface of the transfer recording layer or the image receiving surface of the image receiving sheet. A plurality of nozzles and a substantially fixed nozzle head for forming a latent image by imagewise discharging droplets of a latent image forming liquid containing a neutral material, and transfer recording of the latent image forming liquid An image forming apparatus comprising: a pair of pressure rollers having a heating unit capable of controlling a heating temperature on at least one of the pair of pressure rollers, which can pass the layer surface and the image receiving surface of the image receiving sheet in close contact with each other, and can control the heating temperature. apparatus.