JPH0725165A - Image forming method - Google Patents

Abstract

PURPOSE:To easily form the image corresponding to the image of an already present image manuscript from the image manuscript by simple operation using a simple device. CONSTITUTION:In an image forming method, a thermal color erasing type thermal recording material containing dye particles developed by preliminarily reacting a leuco dye and a phenolic coupler and a color erasing material is brought into contact with a thermal head heated corresponding to the manuscript image signal obtained by optically reading a manuscript image and the negative image of the manuscript image erased by the heat energy from the thermal head is formed on the thermal color erasing type thermal recording material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a negative image (negative image) on a heat-decoloring type heat-sensitive recording material according to an original image, and more particularly to a transmission image forming method suitable for use in an overhead projector. .

[0002]

2. Description of the Related Art A heat-sensitive recording material having a heat-sensitive color forming layer provided on a support such as paper or plastic film is widely known and has been put to practical use in facsimiles, word processor printers and the like. Such a heat-sensitive recording material has advantages such that recording can be performed in a short time with a compact device, environmental pollution is small, and manufacturing cost is low.
On the other hand, a negative-type heat-sensitive recording material (heat-decoloring type heat-sensitive recording material) in which the recording surface is decolored or decolored by thermally scanning a colored surface is
Overhead projector (OHP) sheet,
It is said to be useful as a hard copy of a CRT image used in the medical field using an X-ray imaging apparatus, an ultrasonic diagnostic apparatus, a CT scanner and the like. Conventionally, positive type OHP sheets are generally prepared by analog electrophotography. Negative type OHP sheets, which are easy on the eyes, have come to the fore, but negative type OHP sheets are
Up to now, it has been prepared by a digital electrophotographic method or a transfer heat-sensitive method, and in general, it could not be easily prepared.

[0003]

When a high-sensitivity heat-decoloring type heat-sensitive recording material is used, a negative-type OHP sheet can be prepared by using, for example, a heat-sensitive printer such as a word processor. However, with this method, an existing image original is used, and a negative type O corresponding to the image is used.
It is not possible to create HP sheets. Therefore, an object of the present invention is to provide an image forming method for forming a negative image corresponding to an existing image original from an already existing image original by a simple and easy operation using a simple device.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-bleaching type heat-sensitive recording material containing dye particles and a color-erasing material which are colored by reacting a leuco dye and a phenolic developer in advance.
A negative image of the original image, which has been erased by the thermal energy from the thermal head, is formed on the thermal decoloring type thermal recording material by bringing it into contact with a thermal head that is heated according to the original image signal obtained by optically reading the original image. Was achieved by an image forming method comprising:

The present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an outline of a flow of a particularly preferable embodiment of the image forming method of the present invention. In FIG. 1, scanner image data (original image signal) obtained by optically scanning an original image is stored in a line memory via a CCD I / F (CCD interface), and the image quality of the original image signal is increased according to need. The image is corrected and stored in the image memory, and this image signal is sent to the thermal head via the thermal head I / F, and head printing is performed on the heat-decolorable thermal recording material according to the image signal. That is, using a positive image original, an image signal obtained by inverting the image signal of the original is sent to the thermal head, and the negative image of the original image can be heated and recorded on the heat-decoloring type thermal recording material by the thermal head. . It is also possible to use a negative image original and send the image signal of the original image as it is to the thermal head to heat-record the negative image on the heat-decolorable thermal recording material. The individual operations themselves in each step shown in FIG. 1 can be performed by known methods. For example, the optical scanning reading of an original image can be performed by using a reading device used in a facsimile, and a thermal head such as that provided in a facsimile or a thermal printer is used as a thermal head. You can record heat sensitively.

The image forming method of the present invention will be described with reference to FIG. 2 showing one specific example of the image forming apparatus which can be used for carrying out the present invention. FIG. 2 is a partial cross-sectional perspective view showing a specific example of an image forming apparatus that can be used to carry out the present invention. In FIG. 2, the image forming apparatus 1 includes a document insertion opening 2, a document transporting roller 3, a scanner 4, an image signal processing unit 5, a heat-decolorable thermal recording material cartridge 6, and a heat-decolorable thermal recording material transport. An image forming roller 7, a platen roller 8, a thermal head 9, and an image-formed heat-decoloring type thermal recording material discharge port 10 are provided in a main body case 11. The scanner 4 is a device for reading an image of a document by optical scanning, such as used in a document reading device of a facsimile. The image signal processing unit 5 stores the scanner image data shown in FIG. 1 in a line memory via a CCD I / F (CCD interface), and corrects the image quality of the original image signal as needed (further, if necessary). Is a unit that performs signal processing until the original image signal is converted to an inverted image signal and stored in an image memory and the image signal is sent to the thermal head 9. The thermal head 9 is a scanning thermal head that is heated according to an image signal, such as that provided in a facsimile or a thermal printer.

In FIG. 2, the document A is inserted from the document insertion port 2 with the image surface facing downward, and is transported by the document transport roller 3 in the direction of arrow a by passing over the scanner 4. In the meantime, by the scanner 4 located under the original A,
The image of the document A is read by optical scanning. The signal read by the scanner 4 is processed by the image signal processing unit 5 as described with reference to FIG. 1 and sent to the thermal head 9. On the other hand, the heat-decoloring type heat-sensitive recording material B taken out from the heat-decoloring type heat-sensitive recording material cartridge 6 in response to the insertion of the original A is conveyed by the heat-decoloring type heat-sensitive recording material conveying roller 7, and the platen roller 8 Thus, it moves in the direction of the arrow b while contacting the thermal head 9 and is discharged from the image-formed thermal decoloring type thermal recording material discharge port 10. When the heat-decoloring type heat-sensitive recording material B is in contact with the heat-sensitive head 9, heat energy is applied from the heat-sensitive head 9 to the heat-decoloring type heat-sensitive recording material B according to an image signal, and heat energy is applied. The part is erased and a negative image corresponding to the original image is formed. The rotation speeds of the document conveying roller 3 and the heat-decoloring type heat-sensitive recording material conveying roller 7 are synchronized, and the rotation speeds of the document conveying roller 3 and the heat-decoloring type heat-sensitive recording material conveying roller 7 are By changing it, the printing density on the heat-erasable type heat-sensitive recording material B can be changed. The image formation by the thermal head 9 may be slightly delayed from the reading of the original image by the scanner 4, and the image-formed heat-decoloring type thermal recording material B may be taken out while the original A is being fed, and the original image signal is stored in the memory. After that, an image may be formed on the heat-decoloring type heat-sensitive recording material B after reading the original.

The heat-decoloring type heat-sensitive recording material which can be used in the image forming method of the present invention has a high heat-sensitive layer in which the heat-sensitive layer is decolored by the heat energy applied by the heat-sensitive head (for example, energy of about 10 mJ / mm ² or more). Any form may be used as long as it has sensitivity. As such a heat-erasable type heat-sensitive recording material, a heat-erasable material containing dye particles and a color-erasing material, which are produced by reacting a leuco dye and a phenolic developer in advance, in the same layer or in separate layers. Color-type heat-sensitive recording materials can be mentioned. As a preferred specific example of the high-sensitivity heat-decoloring type heat-sensitive recording material as described above, a leuco dye and a phenolic developer are preliminarily reacted to develop a color, and a hydrophilic particle containing the dye particle in a dispersed state. Of a hydrophilic binder and substantially free of a particulate decoloring agent, and when heat energy is applied, decoloring is caused by the interaction between the pigment particles and the hydrophilic binder, and at room temperature. An example of the heat-sensitive color-erasable heat-sensitive recording material is a heat-sensitive layer in which the heat-sensitive layer which maintains the color-erased state when it is returned to 1.

The leuco dye in the above heat-decoloring type heat-sensitive recording material is preferably a dye containing a lactone ring used in conventional heat-sensitive recording materials. Preferred examples thereof are triphenylmethanephthalide-based, fluorane-based, and indolylphthalide-based leuco dyes. As a preferred specific example,
3,3-bis (p-dimethylaminophenyl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6
-Dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3, 3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluorane, 3- (N, N-diethylamino) -5-methyl-7
-(N, N-dibenzylamino) fluorane, 3-dimethylamino-5,7-dimethylfluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino -6
-Methyl-7-chlorofluorane, 3-pyrrolidino-6
-Methyl-7-anilinofluorane, 2- (N- (3 '
Examples include -trifluoromethylphenyl) amino) -6-diethylaminofluorane, 2- (3,6-bis (diethylamino) -platen roller 9- (o-chloroanilino) xanthyl benzoate lactam) and the like.
The amount of leuco dye used is 0.05 to ² g / m ² , preferably 0.1 to 1 g / m ² .

In the above heat-decoloring type heat-sensitive recording material, the color developing agent is a phenolic compound. When an organic acid or a metal salt thereof, which is generally known as a developer in a heat-sensitive recording material, is used as the developer in the above heat-bleaching type heat-sensitive recording material, the color disappears during heating recording. However, it is not preferable because the color is recovered when the temperature is returned to room temperature. The phenolic color developer that is preferably used in the above heat-decoloring type heat-sensitive recording material has a melting point in the range of 50 to 250 ° C.,
More preferably, it has a melting point within the range of 60 to 200 ° C., and is hardly soluble in water. Preferred specific examples of the phenolic color developer include 4,4′-isopropylidene-diphenol (bisphenol A), p-tert-butylphenol, 2,4-dinitrophenol, 3,4.
-Dichlorophenol, 4,4'-methylene-bis (2,6-di-tert-butylphenol), p-phenylphenol, 4,4-cyclohexylidenediphenol, 2,2'-methylenebis (4-tert-butylphenol) ), 2,2′-methylenebis (α-phenyl-p-
Cresol) thiodiphenol, 4,4'-thiobis (6-tert-butyl-m-cresol), sulfonyldiphenol, 1,1-bis (4-hydroxyphenyl)
2-ethyl-n-hexane, 1,1-bis (4-hydroxyphenyl) -n-dodecane, 4,4-bis (4-
Examples thereof include hydroxyphenyl) -1-pentanoic acid ethyl ester. The higher the amount of the phenolic color developer used, the higher the color density, but it becomes difficult to erase the color by heating. Therefore, in the above heat-decoloring type heat-sensitive recording material, the amount of the phenolic color developer used is preferably 1 to 20 times, more preferably 2 to 10 times the mol of the leuco dye. Is more preferable.

In the above heat-decoloring type heat-sensitive recording material, it is preferable that the dye particles produced by contacting the leuco dye and the phenolic developer in advance to cause coloration are as fine as possible. In particular, the above heat-decoloring type heat-sensitive recording material is used as an OHP.
When used in applications where transparency is important, such as dyes, the average particle size of the dye (color former) particles produced by the reaction of the leuco dye and the phenolic developer is 1 μm or less, and particularly, 0. It is preferably in the range of 01 to 0.4 μm.
As a method for producing such a color body of fine particles,
Leuco dyes and phenolic color developers are dissolved in water insoluble or insoluble organic solvents, such as ethyl acetate, isopropyl acetate, methyl ethyl ketone, etc., and the resulting solution is emulsified and dispersed in an aqueous medium to form fine oil droplets. After that, the method of removing the solvent is preferable. At this time, it is possible to coexist with a high boiling point oil. As the oil, a hydrocarbon oil that does not inhibit the color development of the leuco dye is preferable. When oil is added, the sensitivity tends to increase, but the background density decreases, so the amount used is preferably the same as or less than the total amount of the leuco dye and the color developer. According to the conventional method in which the leuco dye and the color developer are dispersed together in an aqueous medium at high temperature, or the separately dispersed substances are mixed with an organic solvent, the particle size of the color-forming dye particles produced tends to be large. Tend.

In the above heat-bleaching type heat-sensitive recording material, dye particles obtained from a leuco dye and a phenol developer are dispersed in a hydrophilic binder. This hydrophilic binder may be any of generally known hydrophilic polymers such as nonion, anion, and cation polymers. For example, functional groups such as a hydroxyl group, a carbonyl group, an ether group, and an amino group are included in its molecular structure. Polymers having groups are mentioned. Specific examples of the hydrophilic binder include those described on pages 128 to 134 of Known Technology No. 5 (March 22, 1991, issued by Aztec Co., Ltd.). However, depending on the polymer, there are those that exhibit the decoloring action of the color-developing material during the production of the heat-decoloring type heat-sensitive recording material, so it is necessary to pay attention to the conditions of use. A particularly preferable material as the hydrophilic binder used in the above heat-decoloring type heat-sensitive recording material is gelatin and polyvinyl alcohol (PVA), which can also be used as a dispersion polymer when emulsifying and dispersing a leuco dye and a color developer. Is. Gelatin is most preferable because it has a high initial density of the color-developing material and is easily decolored when heated. The above hydrophilic binder is contained in an aqueous medium when emulsifying and dispersing the leuco dye and the developer, or after emulsifying and dispersing the leuco dye and the developer, a heat-sensitive layer forming liquid before coating. It may be added additionally. In the above heat-decolorable heat-sensitive recording material, the weight ratio of hydrophilic binder / phenolic developer is preferably in the range of 0.8 to 10. If the amount of the hydrophilic binder is less than the above range, the sensitivity during heating tends to be low and white spots in the printed portion tend to be insufficient,
If the amount of the hydrophilic binder is larger than the above range, the density of the color-developing material (background density) tends to be insufficient.

In the above heat-bleaching type heat-sensitive recording material, the heat-sensitive layer contains a particulate decoloring agent, such as a) alkylene oxide adducts of bisphenols, which has been conventionally used for heat-sensitive paper. , B) amide compounds such as methylolamide and bisamide, acetamide, c) long-chain 1,2-glycol, d) ethylene oxide adduct of terephthalic acid, e) solid alcohol such as stearyl alcohol, f) polyether or polyethylene glycol. , G) a guanidine derivative, h) an amine or a quaternary ammonium salt is not substantially contained. In the present specification, the term "substantially free of a particulate decoloring agent" means that the content of the particulate decoloring agent in the heat-sensitive layer is 0, or it is more than 0.05 g / m ^2. Means less. The above heat-erasable type heat-sensitive recording material maintains a sufficiently stable color density of the heat-sensitive layer when stored at room temperature. For example, it is stored for one month in an atmosphere of a temperature of 25 ° C. and a relative humidity of 50%. If this is done, the decrease in concentration is 10% or less.

The heat-sensitive layer in the above heat-bleachable heat-sensitive recording material is erased by the interaction of the dye particles and the hydrophilic binder when heat energy is applied, and is erased even when returned to room temperature. It has the property that the color state is maintained. The thermal energy required for decoloring the heat-sensitive layer of the above heat-decolorable heat-sensitive recording material is sufficient to be about 10 mJ / mm ² or more, and from this fact, the heat-decolorable heat-sensitive recording material is It can be said that the sensitivity is extremely high. The conventional heat-erasable heat-sensitive recording material contains about a few g / m ² of a particulate decoloring agent. In the above heat-decolorable heat-sensitive recording material, the heat-sensitive layer has a particulate eraser. The fact that high-sensitivity erasable recording can be performed despite the fact that the colorant is not substantially contained is not known at all in the past and cannot be expected by those skilled in the art. Further, the above heat-decoloring type heat-sensitive recording material, since the heat-sensitive layer contains substantially no particulate decoloring agent,
It also has excellent performance of having good transparency and greatly improving storage stability. Although the mechanism of high-sensitivity color-erasable recording in the above heat-discolorable heat-sensitive recording material is not necessarily established, the hydrophilic binder is used to impart dye particles to the heat-sensitive layer by imparting heat energy. It is considered that the dye is decolored by entering the bond between the leuco dye and the developer in the medium and moving the developer away from the leuco dye.

As the transparent support used in the heat-decoloring type heat-sensitive recording material, a plastic film is preferable. Examples of the plastic film include polyester films such as polyethylene terephthalate and polyethylene naphthalate, cellulose derivative films such as cellulose triacetate film, polyolefin films such as polystyrene, polyethylene and polypropylene, polyimide films, polyvinyl chloride films, polyvinylidene chloride. Examples thereof include films, polyacrylic films, polycarbonate films and the like. As the transparent support used in the heat-decoloring type heat-sensitive recording material, a polyester film subjected to heat treatment and antistatic treatment is particularly preferable. Further, for the purpose of preventing the heat-sensitive layer from peeling off from the transparent support, it is preferable to provide an undercoat layer on the transparent support before applying the heat-sensitive layer to the transparent support. Examples of the material for the undercoat layer include polymers such as gelatin, acrylic acid ester copolymer, polyvinylidene chloride, styrene butadiene latex and water-soluble polyester. The thickness of the undercoat layer is preferably 0.1 to 0.5 μm.

The above-mentioned undercoat layer is preferably a conductive undercoat layer in order to prevent the adhesion of the heat-decoloring type heat-sensitive recording materials to each other and improve the transportability. The conductive undercoat layer is a layer in which fine particles of a conductive metal oxide having an average particle size of 0.2 μm or less are dispersed in a binder made of a polymer, and the surface electric resistance thereof is 1 × 10 ¹⁰ to 1 ×. Range of 10 ¹³ Ω (25 ° C, 6
It is preferably in the range of 5% RH). And 10 ° C, 30% RH, 25 ° C, 65% RH and 30
It is preferably within the above range under all conditions of ° C and 90% RH. The material of the conductive metal oxide particles is Zn
O, TiO, SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , Si
O ₂ , MgO, BaO and MoO ₃ can be mentioned. These may be used alone or as a composite oxide of these. The metal oxide preferably further contains a different element, for example, Al, In, etc. for ZnO, Nb, Ta, etc. for TiO, Sn.
O ₂ is preferably one containing (doping) Sb, Nb, a halogen element or the like. Among these,
SnO ₂ doped with Sb is particularly preferable because it has a small change in conductivity over time and high stability. The fine particles of the metal oxide used in the above heat-bleaching type heat-sensitive recording material preferably have a small particle size in order to suppress light scattering as much as possible. In a transparent heat-decoloring type heat-sensitive recording material that can be used for an OHP (overhead projector), that is, a heat-decoloring type heat-sensitive recording material of a type that can be used by projecting an image, the scattering efficiency is 20% or less. preferable. For this purpose, the average particle diameter of the conductive metal oxide particles needs to be 0.2 μm or less, preferably 0.1 μm or less.

The polymer used in the conductive undercoat layer is not particularly limited. As the water-soluble polymer, polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyhydroxyethyl acrylate, polyvinylpyrrolidone, water-soluble polyester, water-soluble polyurethane, water-soluble nylon, water-soluble epoxy resin, gelatin, hydroxyethyl cellulose, hydroxypropyl cellulose, Carboxymethyl cellulose and derivatives thereof can be mentioned. As the polymer other than the water-soluble polymer, acrylic resin, polyester, polyvinyl acetate,
Mention may be made of SBR (styrene-butadiene rubber), which are generally preferably used as aqueous polymer dispersions or emulsions. In the above heat-decoloring type heat-sensitive recording material, it is particularly preferable to use it as a polymer aqueous dispersion. A preferable polymer for forming an aqueous polymer dispersion is a water-dispersible polymer such as acrylic resin or polyester. This water-dispersible polymer has a polar group (eg, quaternary ammonium salt group, sulfonate group, sulfonate group, carboxylic acid group, carboxylate group, phosphate group, phosphate group) in the molecule of 0.1. It is preferably in the range of 10 to 10% by weight, more preferably in the range of 1 to 5% by weight. As the polar group, carboxylic acid ammonium salt is preferable. An acrylic resin is particularly preferable for the undercoat layer. A crosslinking agent, a surfactant, or the like may be added to these polymers.

The mixing ratio of the metal oxide fine particles and the water-soluble or water-dispersible polymer is preferably in the range of 1: 3 to 3: 1 by weight. The layer thickness of the conductive undercoat layer is 1 × 10 in the humidity range where the surface electric resistance is 30 to 90% RH.
^{It is} generally 0.01 in order to be in the range of ¹⁰ to 1 × 10 ¹³ Ω.
The range is from ˜1.00 μm, preferably from 0.05 to 0.5 μm. The conductive undercoat layer is formed, for example, by dispersing or dissolving the metal oxide fine particles, the binder, the surfactant and the like in water, coating the obtained coating liquid on the transparent film, and drying by heating. Can be carried out. The coating can be performed by a known coating method such as an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, and a bar coater.

In the above heat-decoloring type heat-sensitive recording material,
A protective layer may be provided on the heat-sensitive layer to impart water resistance and scratch resistance to the heat-sensitive layer. Examples of the material for the protective layer include polyvinyl alcohol, modified polyvinyl alcohol, gelatin, styrene maleic anhydride copolymer, starch and the like. These materials may be used alone or as a mixture of two or more kinds, and if necessary, a curing agent for curing these materials may be used, and borax, boric acid, colloidal silica and the like may be used. You may add. Furthermore, in order to improve the handleability and prevent the adhesion to the thermal head during thermal recording, the protective layer has a lubricant such as zinc stearate and paraffin wax, kaolin,
A pigment such as calcium carbonate may be used to the extent that transparency is not impaired. The coating amount of the protective layer is 0.1 to 3
It is preferably g / m ² .

The above heat-decoloring type heat-sensitive recording material can easily form a transparent image on a colored background from an image original by the image forming method of the present invention. Particularly, it is useful as a heat-decoloring type heat-sensitive recording material for producing an OHP sheet.

[0021]

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto. [Example 1] Preparation of coating liquid for conductive undercoat layer 1.55 g of water-soluble acrylic resin (Jurimer ET-410; ammonium carboxylate: 2 wt%; manufactured by Nippon Pure Chemical Industries, Ltd.) Antimony-doped tin dioxide 1.80 g (SN-88; average particle size: 88 nm, manufactured by Ishihara Sangyo Co., Ltd.) Sodium sulfonate-based surfactant 0.125 g (Sanded BL, manufactured by Sanyo Chemical Co., Ltd.) Nonionic surfactant 0. 125 g (EMALEX / NP8.5; manufactured by Nippon Emulsion Co., Ltd.) Pure water 96.4 g (weights other than pure water represent solid content or nonvolatile content)

Preparation of transparent support film The above coating solution for the conductive undercoat layer was coated on one side of a 100 μm thick corona-discharge-treated polyethylene terephthalate film using Bar Coat # 2.4 at a coating speed of 105 m.
/ Min and dried at 185 ° C for 10 minutes to obtain a layer thickness of 0.
A transparent support film having a 15 μm conductive undercoat layer was prepared. For the transparent support film, an insulation meter (TR-8601, manufactured by Advantest Corporation)
10 ° C, 30% RH, 25 ° C, 65% RH and 30 ° C,
The surface electric resistances (Ω) measured 1 minute after the energization under the condition of 90% RH were 5 × 10 ¹⁰ , 1 × 10 ¹¹ , and 5 × 10 ¹¹ , respectively.

Preparation of Coloring Dye Dispersion (NB-1) 2.2 g of the following leuco dye (LD-1) and 6.4 g of the following phenolic developer (PH-1) were added to ethyl acetate 3
It was dissolved in 0 g. On the other hand, 57 g of a 14% aqueous solution of lime-processed gelatin and 5 g of a 5% aqueous solution of sodium dodecylbenzenesulfonate were mixed and placed in a 200 cc homogenizer cup. Into this, add the above dye solution to 1000
The mixture was stirred at 0 rpm for 5 minutes to obtain a color dye dispersion (NB-1) having a particle size of about 0.3 μm.

[0024]

[Chemical 1]

Preparation of heat-decoloring type heat-sensitive recording material 101 To 4.2 g of the coloring dye dispersion (NB-1), 7.5 g of water and 3 g of a 1% aqueous solution of the following surfactant (WW-1) were added, Mixed. This liquid was applied on the conductive undercoat layer of the transparent support film at a coating amount of 31.5 cc / m ² and dried to give a substantially transparent blue heat-decolorable thermosensitive recording material 101.
Got

[0026]

[Chemical 2]

A negative image was formed on the heat-erasable heat-sensitive recording material 101 by the method of the present invention by using the image-forming apparatus as shown in FIG. 2 and the heat-erasable heat-sensitive recording material 101. Disappeared and became transparent. When this was projected with a transmission type OHP, an extremely clear image could be read.

[0028]

According to the image forming method of the present invention, it is possible to form a negative image corresponding to an existing image original from an existing image original by a simple and inexpensive apparatus and by an easy and simple operation. Has a remarkable effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a flow of a particularly preferable embodiment of an image forming method of the present invention.

FIG. 2 is a partial cross-sectional perspective view showing a specific example of an image forming apparatus that can be used to carry out the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Original insertion port 3 Original transport rollers 4 Scanner 5 Image signal processing unit 6 Thermal decolorizable thermal recording material cartridge 7 Thermal decolorizable thermal recording material transport roller 8 Platen roller 9 Thermal head 10 Image formed Thermally erasable thermal recording material discharge port 11 Body case

Claims (3)

[Claims] 1. A heat-decoloring type heat-sensitive recording material containing dye particles and a decoloring material, which are colored by reacting a leuco dye and a phenolic developer in advance, is converted into a document image signal obtained by optically reading a document image. Touch the thermal head, which is heated accordingly.
An image forming method comprising forming a negative image of a document image which has been erased by heat energy from a thermal head on the thermal erasable thermal recording material. 2. The heat-decoloring type heat-sensitive recording material comprises dye particles which are colored by reacting a leuco dye and a phenolic developer in advance, and a hydrophilic binder containing the dye particles in a dispersed state. A layer that does not substantially contain a particulate decoloring agent, and when heat energy is applied, decolorizes due to the interaction between the dye particles and the hydrophilic binder, and also when the temperature is returned to room temperature. The image forming method according to claim 1, wherein the heat-sensitive layer in which the color state is maintained is a heat-decolorable heat-sensitive recording material formed on a transparent support. 3. The image forming method according to claim 1, wherein the optical reading of the original image is performed by a scanning method, and the thermal head is a scanning thermal head.