JP2000351280A - Image forming apparatus and thermal transfer recording medium - Google Patents

Abstract

(57) [Problem] To form an image including gradation, and to provide an image having security in the formed image plane, or to form an image including gradation in an image including gradation. Provided is an image forming apparatus that can provide security. A heat-sensitive transfer recording medium in which a colored layer using at least one of a pigment and a dye is provided on a support,
The thermal transfer recording image is written on the intermediate transfer medium on the intermediate transfer medium holding member by melt-transferring the thermal transfer recording medium based on the image information, and the intermediate transfer medium is heated and pressurized on the transfer receiving body, so that the intermediate transfer medium is heated and pressed. In an image forming apparatus for transferring an image from a transfer medium to a transfer receiving body, a metal having a crystal structure is internally added to an individual thermal transfer recording material having no coloring layer or coloring agent. The direction and amount of the pattern of the diffracted X-ray when irradiating the line can be used as individual information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming a dot-shaped area gradation image by thermal transfer.
In particular, the present invention relates to an image forming apparatus that incorporates various security technologies inside an image.

[0002]

2. Description of the Related Art Conventionally, as a method of writing an image on an intermediate transfer medium based on image information, a thermal transfer method, an electrophotographic method, and an ink jet method described in the present invention are used in addition to a printing method which is most frequently used in practice. Method, thermal destruction method, and various transfer recording methods using a photopolymerized recording material can be cited as technically possible examples.

[0003] It is difficult to form an image directly on a final recording medium (final product) to which an image is to be applied by using these image forming methods, or the mass productivity is poor.
Alternatively, when there is any problem such as high cost, as described above, a method of forming an image on an intermediate transfer medium and then applying the image to a final product by transfer is used. Has been adopted.

In the case where the image forming method is, for example, a thermal transfer method using a sublimable dye, a thermal transfer ribbon having a sublimable dye coated on a base film so as to be capable of thermal transfer is used for final recording. A heat transfer ribbon is selectively heated based on image data prepared by using a thermal head or the like, and a desired image is transferred onto the transfer object. It is widely known as a known fact to record.

According to this means, for example, in a case where the face of each person or the like is individually recorded on an individual transfer-receiving body,
An advantage that cannot be seen by the printing method is obtained in that a large number of images different from each other can be easily recorded as a color image with rich gradation on a transfer receiving body. If it is attempted to print such a record of the face of each person by a printing method, it is generally uneconomical since a great deal of cost, labor and time are generally required.

However, thermal transfer recording methods using sublimable dyes also have disadvantages. That is, the materials that can be dyed with the sublimable material are limited, and can be applied only to a transfer target made of a limited material such as, for example, polyester, acrylic resin, and vinyl chloride resin.

In order to perform thermal transfer recording using a sublimable dye in spite of using a material other than the above as a material to be transferred, for example, Japanese Patent Application Laid-Open No. As disclosed in JP-A-81093, in an image writing section using a transfer ribbon of a sublimable dye and a thermal head, first, an image is written on a film-like intermediate transfer medium having an adhesive layer, and then transferred. There has been proposed a method in which an image on an intermediate transfer medium is heated and pressed together with the adhesive layer on an object to be transferred by using a transfer roller, and the image is transferred to the object to be transferred.

Although this method is only an example of a sublimable dye, it is not possible to form an image directly on a transfer-receiving body for various reasons. The method of transferring the image to the transfer object together with the layer on which the image is formed is basically the same, and this recording method is hereinafter referred to as an indirect transfer method. For example, final products (recording media)
It is possible to directly form an image on a transferred object for various reasons, such as when the thickness of the transferred object is not constant, when there is unevenness, or when the transferred object is a semi-finished product such as a booklet in advance. It is not an exaggeration to say that when it is not possible, or when it takes a lot of cost and time to form an image, it is possible to form an image only by the indirect transfer method.

However, when an electrophotographic method is used as a method of writing an image on an intermediate transfer medium based on image information, in order to form a full-color image, it is necessary to charge the photosensitive member and expose the charged photosensitive member. Image formation, development of a toner image corresponding to a latent image on a photoreceptor, transfer of an image to a transfer member such as a transfer drum for temporarily storing a toner image of each color, erasure of an unnecessary charged portion on the photoreceptor It is necessary to repeat the electrophotographic process, such as cleaning on the photoreceptor, three or more times (three-color) or four times (four-color). Instability of image formation due to the use of the object occurs. Further, since the size of the dots of the toner image forming the image cannot be changed so much, it is basically a binarized image, and a pseudo area floor by a dither matrix such as a Bayer type or Fatton type (including a screw type). If the tone method is not used, it is impossible to express the density change of the image, and there is a big problem that the image itself is rough.

Next, when the ink jet method is used,
Since an image is formed on an intermediate transfer medium using liquid ink, it is necessary to dry the intermediate transfer medium, which causes a problem of nozzle clogging. Furthermore, even in the case of the ink jet method, since the size of the dot cannot be changed so much, a method of a pseudo area gradation such as a dither matrix or an error diffusion method is used, so that the resolution of the image tends to be coarse. It is in. And for the thermal destruction method, it is impossible to perform full color expression at present.

For these reasons, since image formation by a thermal transfer method using a sublimable dye can be realized simply, at low cost, and with high image quality and high resolution, it is particularly excellent as an image formation method in the indirect transfer method. It can be said that. However, the thermal transfer method using a sublimable dye has a major drawback. It is said that the sublimation dye itself is a color material with very low resistance, such as heat resistance, light resistance, and solvent resistance. Is very poor in image durability. For this reason, for example, when the transfer target is an IC card having a heat-resistant temperature of about 120 ° C., a decrease in image density due to a phenomenon such as thermal decomposition or re-sublimation of a sublimation dye occurs even at about 80 ° C. It is impossible to clear the heat-resistant temperature 120 ° C of the body.

Further, when paper such as a passport is used as the transfer object, the image is bleeding from the back side of the paper on which the image has been transferred due to a solvent atmosphere such as paradichlorobenzene or naphthalene which is often used as an insect repellent. Also, when the temperature is high, various problems such as a decrease in image density due to the re-sublimation of the sublimable dye from the paper fibers occur.

Furthermore, since the sublimation type printing method itself is widely used in the world, when used for security purposes such as passports, forgery and tampering tend to be easily performed, and forgery or falsification tends to occur. There is also a problem that even if it is tampered with, it is difficult to distinguish between authenticity and authenticity.

[0014] To solve such a problem unique to the sublimation dye,
In addition, in order to realize simple, low cost, high image quality and high resolution by the thermal transfer method, an area for performing density gradation by changing the size of a dot to be transferred according to the amount of heat generated by a thermal head used for thermal transfer. The gradation type thermal transfer printing method is very effective.

For example, a coloring material such as an organic dye, an organic pigment, or an inorganic pigment is added to a binder resin such as polymethyl methacrylate, polybutyral, a vinyl chloride-vinyl acetate copolymer, a urethane resin, or polystyrene acrylate. An ink internally added, and if necessary, a wax component, a filler, etc., may be added to polyethylene terephthalate (abbreviated as PET) or polyethylene naphthalate (P).
EN), the ink ribbon formed in advance by a printing method or the like on a support is softened by a controlled amount of heat from a thermal head, and the area to be softened is changed according to the amount of heat. This is a fusion transfer method that enables gradation.

In this method, a dye or a pigment other than a sublimable dye can be used as a coloring material, so that durability such as heat resistance, solvent resistance, light resistance, etc. can be greatly improved. It can be said that this method has a very high requirement conformity in the field where high durability is required such as a driver's license.

[0017] Originally, the area gradation type melt transfer method is very sensitive to the unevenness of the recording medium to be transferred, and if there is even a small amount of unevenness, the image cannot be directly transferred and formed. In other words, it can be said that it is almost impossible to obtain a high-quality image by the area gradation type fusion transfer method other than the indirect transfer method.

[0018]

By the way, when the indirect transfer method is used for high security applications and needs such as passports and visas, ordinary colors,
Security technology other than image information such as monochrome (single color) is required. For example, light diffraction such as hologram,
A method of incorporating a reflective pattern into the image layer of the intermediate transfer medium and transferring this pattern together with the image during the heating and pressurizing transfer onto the transfer target has been devised and put into practical use. Is the same pattern made in advance,
There was a problem that it was not possible to make patterns correspond individually.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and forms an image including a gradation characteristic and simultaneously forms an image having each security property on the side of the formed image. It is an object of the present invention to provide an image forming apparatus which can be provided, or which can have various security properties inside an image including gradation, and a thermal transfer recording medium suitable for the image forming apparatus.

[0020]

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention is directed to an image forming apparatus comprising: an intermediate transfer medium on an intermediate transfer medium holding member; Using a heat-sensitive transfer recording medium in which at least one colored layer is provided on a support, a heat-sensitive transfer recording image is written by melt-transferring the heat-sensitive transfer recording medium based on image information, and then the above-described method is performed. An image forming apparatus configured to transfer the image from the intermediate transfer medium to the transfer target by heating and pressurizing the intermediate transfer medium to the transfer target, and to perform individual image sensing without the coloring layer or the colorant. Since a metal having a crystal structure is internally added to the thermal transfer recording material, it is possible to use the direction and amount of a diffracted X-ray pattern when X-rays can be used as individual information. To.

Next, an image forming apparatus according to a second aspect of the present invention comprises:
Since the crystal structure of the metal internally added to the heat-sensitive recording material is two or more, for example, by changing the metal to be internally added to a face-centered cubic lattice and a body-centered cubic lattice, X
It is characterized in that a change can be given to a diffraction pattern when a line is irradiated. Also, even with the same body-centered cubic lattice, if the type of metal is different, the lattice spacing changes, so it can be said that the crystal structure is different, and even for the same metal, for example, ferrite and martensite in iron, Since the intermolecular distance of the crystal is different, the crystal structure is different.

Further, according to a third aspect of the present invention, there is provided an image forming apparatus comprising:
Since the shape of the metal internally added to the thermal transfer material is a fine powder, the diffraction pattern upon X-ray irradiation is characterized by a donut shape called Debye ring.

According to the image forming apparatus of the present invention, since the metal internally added to the thermal transfer material has a fibrous shape, it uses not only X-ray diffraction but also ultrasonic waves and magnetism as a reader. Characterized by the ability to do

According to the image forming apparatus of the present invention, the intermediate transfer medium on the intermediate transfer medium holding member is provided with a colored layer using at least one of a pigment and a dye as a coloring material on the support. Using a heat-sensitive transfer recording medium provided in the above, writing a heat-sensitive transfer recording image by melt-transferring the heat-sensitive transfer recording medium based on image information, and then heating and pressurizing the above-described intermediate transfer medium to a transfer-receiving body. so,
An image forming apparatus configured to transfer the image from an intermediate transfer medium to an object to be transferred, wherein the individual thermal transfer recording material having no coloring layer or coloring agent emits fluorescence by X-ray irradiation. Since the property is given, it is possible to visualize an X-ray fluorescence image without detecting the X-ray diffraction pattern or the like.

Next, according to the image forming apparatus of the present invention, the heat-sensitive transfer material in the image forming apparatus of any one of the first to fourth aspects is provided with a property of emitting fluorescent light by X-ray irradiation. It is characterized in that the fluorescent image recognition can be used together with X-ray diffraction pattern detection, ultrasonic wave detection and the like.

According to the image forming apparatus of the present invention,
Using a heat-sensitive transfer recording medium in which a coloring layer using at least one of a pigment and a dye as a coloring material is provided on a support on the intermediate transfer medium on the intermediate transfer medium holding member, and based on image information, An image in which a thermal transfer recording image is written by melt-transferring a thermal transfer recording medium, and then the intermediate transfer medium is heated and pressurized on a transfer receiving body to transfer the image from the intermediate transfer medium to the transfer receiving body. Since a photochromic material having a photochromic phenomenon of being visualized by light irradiation is internally added to the individual thermal transfer recording material having no colored layer or colorant in the forming apparatus, It is characterized in that a security image is visualized on an image by irradiating light of high luminance such as a strobe or ultraviolet light.

According to the image forming apparatus of the present invention, the thermal transfer material in the image forming apparatus according to any one of the first to sixth aspects is provided with a photochromatic material which is visualized by light irradiation. Therefore, in addition to reading individual data such as X-ray irradiation, ultrasonic waves, magnetism, etc., it is characterized by higher security by using it together with visualizing a security image on an image.

According to a ninth aspect of the present invention, there is provided a thermal transfer recording medium, wherein a color layer using at least one of a pigment and a dye as a color material is provided on a support, and the color layer or the colorant is provided. It is characterized in that a metal having a crystal structure is internally added to the individual thermal transfer recording material.

Further, the thermal transfer recording medium of claim 10 is
A colored layer using at least one of a pigment and a dye as a coloring material is provided on a support, and individual thermal transfer recording materials having no colored layer or coloring agent are irradiated with X-rays. Is provided with a property of emitting fluorescence.

The thermal transfer recording medium according to the eleventh aspect is provided with a color layer using at least one of a pigment and a dye as a color material on a support, and having the color layer or the colorant. The present invention is characterized in that a photochromatic material which is visualized by light irradiation is internally added to the individual thermal transfer recording material.

[0031]

According to the first aspect of the present invention, there is provided a thermal transfer recording method in which a color layer using at least one of a pigment and a dye as a coloring material is provided on a support on an intermediate transfer medium. Using a medium, a thermal transfer recording image is written by melt-transferring the thermal transfer recording medium based on image information, and then the above-described intermediate transfer medium is heated and pressurized to a transfer-receiving body, thereby transferring the image to the intermediate transfer medium. An image forming apparatus configured to transfer the image to a transfer target from
Since a metal having a crystal structure is internally added to the individual thermal transfer recording material having no coloring layer or coloring agent, when irradiated with X-rays, it is diffracted according to the internally added metal crystal. X-rays are emitted.

This means that a diffraction pattern represented by a Laue photograph can be detected by, for example, X-ray diffraction analysis. In particular, in the case of a metal crystal, the structure of each crystal, for example, austenitic stainless steel (SUS324, 316L, etc.) or Face-centered cubic lattice of aluminum, etc., body-centered cubic lattice of iron, copper, etc., closest hexagonal crystal of magnesium, titanium, etc.
A characteristic diffraction pattern emitted according to (orthogonal) or the like can be created. The difference between these crystals is that X
Since the pattern is limited by the extinction rule of line diffraction,
Pattern recognition of each crystal is easy.

Next, an image forming apparatus according to a second aspect of the present invention
Since the crystal structure of the metal internally added to the heat-sensitive recording material is two or more, for example, by changing the metal to be internally added to a face-centered cubic lattice and a body-centered cubic lattice, X
A change can be given to the diffraction pattern when the line is irradiated. However, the difference in crystal structure here means that, for example, even if the same body-centered cubic lattice is used, if the type of metal is different, the lattice spacing changes, so that it can be said that the crystal structure is different. In the system, since the intermolecular distance of the crystal is different between the ferrite system and the martensite system, different crystal structures are used.

The image forming apparatus according to a third aspect of the present invention further comprises:
Since the shape of the metal internally added to the heat-sensitive transfer material is a fine powder, the diffraction pattern upon X-ray irradiation becomes a donut shape called Debye ring, so that the X-ray diffraction pattern reading portion (sensing portion) Has few placement constraints,
Compatible with simple readers.

According to the image forming apparatus of the present invention, since the metal internally added to the heat-sensitive transfer material has a fibrous shape, in addition to X-ray diffraction, an ultrasonic wave is incident and reflected. The reflected signal, magnetism, etc. at the time of contact can be used as a reader.

According to the image forming apparatus of the present invention, the intermediate transfer medium on the intermediate transfer medium holding member is provided with a colored layer using at least one of a pigment and a dye as a coloring material on the support. Using a heat-sensitive transfer recording medium provided in the above, writing a heat-sensitive transfer recording image by melt-transferring the heat-sensitive transfer recording medium based on image information, and then heating and pressurizing the above-described intermediate transfer medium to a transfer-receiving body. so,
An image forming apparatus configured to transfer the image from an intermediate transfer medium to an object to be transferred, wherein the individual thermal transfer recording material having no coloring layer or coloring agent emits fluorescence by X-ray irradiation. Since the property is given, the X-ray fluorescence image can be used as a security image without having to detect the X-ray diffraction pattern or the like.

Next, according to the image forming apparatus of the present invention, the heat-sensitive transfer material in the image forming apparatus of the first to fourth aspects is provided with the property of emitting fluorescence by X-ray irradiation. Recognition of a fluorescent image emitted by X-ray irradiation can be used together with X-ray diffraction pattern detection and ultrasonic detection.

According to the image forming apparatus of claim 7,
Using a heat-sensitive transfer recording medium in which a coloring layer using at least one of a pigment and a dye as a coloring material is provided on a support on the intermediate transfer medium on the intermediate transfer medium holding member, and based on image information, An image in which a thermal transfer recording image is written by melt-transferring a thermal transfer recording medium, and then the intermediate transfer medium is heated and pressurized on a transfer receiving body to transfer the image from the intermediate transfer medium to the transfer receiving body. A photochromic material having a photochromic phenomenon (a phenomenon caused by a photochromic reaction), which is visualized by light irradiation, is internally added to the individual thermal transfer recording material having no colored layer or coloring agent. Irradiates light from flashes, strobes, other high-intensity light sources, or high energy levels such as ultraviolet light. Accordingly, since the security image is visualized on the image, you can use this image as a security image.

Incidentally, the photochromic reaction is a photochemical reaction in which a hue change occurs. An image melt-transferred by an ink ribbon in which the photochromatic material is internally added is originally transparent, but ultraviolet rays and relatively short images are used. It is visualized by light of a wavelength. Then, the image disappears with the passage of time, but when the light is irradiated again, the image becomes visible.

Further, according to the image forming apparatus of the present invention, a photochromatic material which is visualized by light irradiation is internally added to the heat-sensitive transfer material in the image forming apparatus of the first to sixth aspects. Therefore, in addition to reading individual data such as X-ray irradiation, ultrasonic waves, magnetism, etc., security can be further improved by using the security image on an image in combination with visualization.

According to the thermal transfer recording medium of the ninth to eleventh aspects, it can be suitably used when a security image is formed by the image forming apparatus of any one of the first to eighth aspects.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing an image forming apparatus according to the present invention. A transfer-receiving member 1 (1 ') is provided via a base rubber sheet made of silicon rubber having a surface coated with a fluorine-based polymer compound (not shown). Is set on tray 2 (2 '). The positions of the transfer target 1 and the tray 2 indicated by solid lines are positions when the image on the intermediate transfer medium 6 is heated and pressed on the transfer target 1 by the heat roller 40. The transfer of the non-transferred body is performed by moving the rail 3 to the wheels 4 (4 ′) by an actuator and a drive system (not shown).
Move at 5 (5 ').

Reference numeral 6 denotes an intermediate transfer medium which is supplied from a supply reel 23 and has guide rollers 13, 15, 16,
39 and transport rollers 17, 18 (rotational direction h if advancing) and 20, 19 (rotational direction d if advancing) to the take-up reel 24, and when writing an image, it is placed on the silicon-based elastomer layer. Writing is performed while being held by clamp rollers 8 and 9 on a platen roller 10 covered with a fluorine-based polymer compound. Reference numeral 25 denotes a cleaning roller for removing dust on the platen roller.

In this embodiment, the intermediate transfer medium 6 has a hologram image layer (including an electron beam drawing grid image) which is a diffraction grating image formed by hologram or electron beam drawing, and the hologram image is aligned. The registration is performed on the platen roller 10 by the registration mark sensor 11 for performing the adjustment. Reference numeral 12 denotes a cleaning roller that removes dust on the side of the intermediate transfer medium 6 on which an image is written, and removes dust on the image surface of the intermediate transfer medium together with a neutralization brush (not shown).

On the other hand, in the present embodiment, thermal transfer is performed by using a molten ink using an organic pigment or an inorganic pigment as a coloring material (actually, the ink is thermally softened). The gradation is provided by arbitrarily changing the size of the dot formed by the image data applied to the thermal concentration type thermal head 38 having a substantially square shape of 40 microns square.

The ink ribbon 7 having the molten ink using the pigment is supplied from the supply reel 26 and is supplied to the guide roller 3.
6 and transport rollers 28 (rotation direction g if advancing), 2
9 and cleaning rollers 32 and 3 which also serve as guide rollers
3 and is transferred to a take-up reel 27 by a thermal concentration type thermal head 34 based on image information.
Write an image to the

The ink ribbon 7 is distinguished and positioned by reading sensor marks formed on the ink ribbon in advance by the sensors 30 and 31 in order to distinguish the colors. In addition to the black (ink), cyan, magenta, and yellow colors,
It has a security panel with a photochromic material that is visualized by light.

The photochromic reaction is a photochemical reaction in which a hue change occurs. An image melt-transferred by the security panel is originally transparent, but is visualized by ultraviolet light or light having a relatively short wavelength. Then, the image disappears with the passage of time, but when the light is irradiated again, the image becomes visible.

The intermediate transfer medium having an image formed on the intermediate transfer medium is heated and pressed on the transfer target 1 by lowering the heat roller 40 in the direction b, so that the image on the intermediate transfer medium (the image receiving layer is not formed). A so-called image layer such as a heat bonding layer, a hologram layer and a protective layer (not shown) is transferred by heating and pressing. However, shutters 41 and 42 for safety are provided between the heat roller 40 and the object 1 to be transferred.
Shutter 4 only when heat roller descends in direction b
The shutters 4 are provided so that the directions c and c ′ are open and the human hands or the like do not touch the heat roller 40 and do not get burned.
1, 42 are closed.

The heat roller 40 is a hollow cylinder having a halogen lamp heater 37 inside and a blackened inside to absorb heat radiation from the halon lamp heater. An inverted crown-shaped heat roller provided with a conductive fluorine-based polymer compound on the outermost surface. By rotating the peripheral speed (i.e., the rotation direction is i) slightly faster than the conveying speed of the intermediate transfer medium or the transfer-receiving body, tension is intentionally generated outside the center of the intermediate transfer medium being heated. The generation of a transfer medium is prevented.

The surface temperature of the heat roller 40 is detected by a temperature sensor 21 and is kept constant by a temperature controller or the like (not shown). In order to keep the heat roller surface clean at all times. Is provided with a cleaning roller 22. Then, other detailed conditions in this embodiment are presented as follows.

Intermediate transfer medium properties: Multi-layer coated on 25 μm PET base. A mixed resin mainly composed of urethane resin, epoxy resin, etc. for the image receiving layer and thermal bonding layer on the outermost surface. Ink ribbon properties: Uses organic pigment-based coloring materials. The thickness of the ink layer is 0.2 to 0.6 mm. An ink ribbon containing the following photochromic material can be used. Hg ₃ S ₂ I ₂ , ZnS, hydrazone derivative, osazone derivative, fulgide derivative, stilbene derivative, salicylaldehyde derivative, spiropyran derivative, biimidazolyl derivative, bianthrone, etc. in the binder resin And so on. Base rubber sheet: Silicon rubber (rubber hardness: 50 mm according to JIS (A)) The surface is coated with an ethylene tetrafluoride polymer or a hexafluoropolypropylene polymer. Transfer object: paper base material with a thickness of 200 to 800 μm

Heat roller: Heat source; Halogen lamp heater Temperature control; Temperature control by detecting roller surface temperature Core metal; Hypertonic aluminum Inner blackening treatment Elastomer layer; Heat-vulcanized silicone rubber 0.5mm thick Roller surface material; Copolymer of ethylene tetrafluoride and perfluoroalkyl vinyl ether provided with a surface Roller surface shape: Inverted crown type Circumferential speed is slightly higher than medium conveyance speed Roller surface temperature: 180 ° C Heating / pressing speed: 15 mm / sec Heating / pressing line load: 3.0 kgf / cm Thermal head: Heating part characteristics: Heat-concentrated type Heating part density: 300 dots / inch Heating part shape: Almost square (70 μm square)

As presented above, with respect to the thickness of the ink ribbon, in order to improve the gradation (area gradation), in order to make the ink layer from the support layer (PET film or the like) good, it is necessary to remove the foil. The thickness is preferably set to 1 μm or less, and particularly when the thickness is 0.6 μm or less, a good area gradation of 256 gradations or more is possible.

Now, an actual magnetic recording image will be described with reference to FIGS. FIG. 2 shows a transferred image (final recording medium image) obtained by transferring an image on a booklet as a transfer object in the present embodiment.
However, in the image forming apparatus of the present invention, for example, an inorganic photochromic material such as Hg ₃ S ₂ I ₂ or ZnS, a hydrazone type, an osazone type, a fulgide type, a stilbene type, or a salicylaldehyde type is used for the melt-transferred ink layer. An organic derivative such as spiropyran, biimidazolyl or the like, or an organic substance such as bianthrone was dispersed in a thermoplastic binder resin, for example, a copolymer of vinyl chloride and vinyl acetate, polymethyl methacrylate, or an epoxy resin. Since it can be composed of a photochromic stripe image in the vertical direction, a photochromic stripe image b in the horizontal direction,
A photochromic image can be formed in an arbitrary place such as a ruled line or a portion C, which is a frame for surrounding characters.

As a matter of course, if a photochromic material is internally added to the ink to be formed as a single color or a color image by itself with a colored ink, the image can be formed in that color. Alternatively, the photochromic ink image can be concealed by using an infinitely colorless photochromic ink to match the color of the background color (including preprint) of the booklet. Especially when not irradiating light, with a colorless photochromic material, a copy of the human image data is concealed on the transferred object by a thin fine line or a halftone gradation image on the transferred object, for example, as in G. If it is, it can be used as a watermark in which an image emerges by light irradiation.

Furthermore, if a photochromic material is mixed with one or more ink layers of the gradation image D such as a face image, photochromism can be imparted to the face image. Further, the photochromic image itself can be hidden in the image as the above-mentioned hiding ink.

Further, photochromism can be imparted to the OCR (optically read character) portion E, and it can be included in the personal data F portion. Incidentally, if photochromism is imparted to the standard character portion Q, the color images can be unified in all booklets. Of course, if these characters are tampered with a non-color-forming or non-photochromic ink or the like, no color change due to light irradiation occurs, so that tampering is easily revealed.

Next, a developed example of FIG. 2 will be described with reference to FIG. A part 50 of the part A in FIG. 3 is an example of a ruled line (A) that looks linear when viewed with the naked eye, but is actually an example in which the thickness of the line is delicately changed by gradation recording of ink. Since the density gradation of the photochromic image itself changes due to the difference in the thickness of the photochromic image, an analog modulation can be applied to the density pattern when light is irradiated, and the amount of information increases and the security is improved. In particular, if the data is mechanically read by the analog data image reading reader, it can be used for data such as individual security information. Further, in a part (60) of the portion B, not only the thickness of the line but also the size of each dot is changed in various ways to modulate the two-dimensional photochromic image, so that the information amount is further increased. , Security is also improved.

Further, the gradation image D is a photochromic image itself, which is advanced two-dimensional matrix data, and can form a photochromic image equivalent to the number of area gradations, so that the information amount is further increased and the security is improved.
Further, it can also be used for a watermark having a gradation like G in FIG.

In the present embodiment, a detailed example of the photochromic image has been presented, but various other examples can be presented. For example, the inventors:
We have found that X-rays can be used as a security measure.

For example, 18-20% chromium in the ink,
When austenitic stainless steel internally containing 8 to 10% of nickel is internally added, the amount of heat required to form a melt-transferred image is larger than that of other inks because the specific heat is large. However, an image can be formed. When an X-ray generated by using copper as a target is irradiated on this image through a collimator, a characteristic diffracted light according to an annihilation law caused by the structure of the metal crystal is obtained as in a Laue photograph. In the case of the austenitic stainless steel, the face-centered cubic lattice (F
CC) is obtained. Further, when the metal to be internally added is made into a fine powder to form the ink, each diffraction pattern is radiated in a donut shape, that is, in a so-called Debye ring shape. These are used as security information. Especially when ferrite stainless steel of about 17 to 19% chromium is added to the above stainless steel, the structure of ferrite stainless steel is body-centered cubic lattice (BCC) and its diffraction pattern is different. This allows the diffraction pattern to be changed freely.

If the metal to be added is made into a fiber or chip, an ultrasonic echo pattern based on the pattern is selected. If the metal is a magnetic substance, for example, cobalt ferrite, γ-iron oxide, magnetite Magnetic information such as barium / ferrite, nickel, pamenjur, samarium / cobalt, and alnico alloy can also be obtained.

If a fluorescent substance that emits light by X-ray irradiation is added to the ink, the light emission pattern can be used as a security image without having to detect a diffraction pattern. By the way, a material that emits or emits light by transition of a level such as a Fermi level is widely known to emit light by using a second harmonic such as a long wavelength (for example, light of 850 nm) such as an infrared ray. , These materials can also be used. As described above, according to the present invention, individual information can be drastically included in the transfer target.

[0065]

According to the present invention, there is provided an image forming apparatus which forms an image having a security characteristic in a formed image at the same time as forming an image including a gradation characteristic, or an image forming apparatus including a gradation characteristic. Has been provided with an image forming apparatus having various security properties.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a schematic diagram illustrating a transfer image (final recording medium image) formed on a booklet as a transfer target by the image forming apparatus according to the present invention.

FIG. 3 is a schematic diagram for explaining a further developed example of the transfer image as shown in FIG. 2;

[Explanation of symbols]

1, 1 ': Transfer object 2, 2': Tray 3: Rail 4, 4 ': Wheel 5, 5': Wheel 6: Intermediate transfer medium 7: Ink ribbon 8, 9 Clamp roller 10 Platen roller 11 Registration mark sensor 12 Cleaning roller 13 Guide roller 15 Guide roller 16 Guide roller 17 -Conveying roller 18 ... Conveying roller 19 ... Conveying roller 20 ... Conveying roller 21 ... Temperature sensor 22 ... Cleaning roller 23 ... Supply reel 24 ... Take-up reel 25 ... Cleaning roller 26 Supply reel 27 Take-up reel 28 Transport roller 29 Transport roller 30 Sensor 31 Sensor 32 Cree Cleaning roller (also guide roller) 34 Thermal head (heat concentration type) 36 Guide roller 37 Halogen lamp heater 38 Thermal head (heat concentration) 39) Guide roller 40 Heat roller 41 Shutter 42 Shutter 50 Part of ruled line A 60 Part of ruled line B b Photochromic stripe image (vertical or horizontal) c, c ': shutter opening direction i: rotation direction (heat roller) A: ruled line B: ruled line C: ruled line or boxed character Frame D: gradation image E: OCR section F: personal data section G: duplicated person image data Q: fixed character section

Claims (11)

[Claims] An image information is obtained by using a heat-sensitive transfer recording medium in which a coloring layer using at least one of a pigment and a dye as a coloring material is provided on a support as an intermediate transfer medium on an intermediate transfer medium holding member. The thermal transfer recording image is written by melt-transferring the thermal transfer recording medium based on the above, and then the image is transferred from the intermediate transfer medium to the transfer target by heating and pressurizing the intermediate transfer medium to the transfer target. An image forming apparatus characterized in that a metal having a crystal structure is internally added to the individual thermal transfer recording material having no coloring layer or coloring agent. 2. The image forming apparatus according to claim 1, wherein said heat-sensitive recording material has two or more types of crystal structures. 3. The image forming apparatus according to claim 1, wherein the metal internally added to the thermal transfer material is a fine powder. 4. The image forming apparatus according to claim 1, wherein the metal internally added to the thermal transfer material has a fibrous shape. 5. A thermal transfer recording medium comprising a support and a coloring layer using at least one of a pigment and a dye as a coloring material provided on the intermediate transfer medium on the intermediate transfer medium holding member. The thermal transfer recording image is written by melt-transferring the thermal transfer recording medium based on the above, and then the image is transferred from the intermediate transfer medium to the transfer target by heating and pressurizing the intermediate transfer medium to the transfer target. Wherein the individual thermal transfer recording material having no colored layer or coloring agent is provided with a property of emitting fluorescence by X-ray irradiation. Image forming device. 6. The image forming apparatus according to claim 1, wherein said thermal transfer material has a property of emitting fluorescence by X-ray irradiation. 7. A thermal transfer recording medium in which a coloring layer using at least one of a pigment and a dye as a coloring material is provided on a support is provided on the intermediate transfer medium on the intermediate transfer medium holding member. The thermal transfer recording image is written by melt-transferring the thermal transfer recording medium based on the above, and then the image is transferred from the intermediate transfer medium to the transfer target by heating and pressurizing the intermediate transfer medium to the transfer target. An image forming apparatus, wherein a photochromic material that is visualized by light irradiation is internally added to the individual thermal transfer recording material having no coloring layer or coloring agent. Characteristic image forming apparatus. 8. The image forming apparatus according to claim 1, wherein a photochromatic material which is visualized by light irradiation is internally added to said thermal transfer material. 9. A coloring layer using at least one of a pigment and a dye as a coloring material is provided on a support, and the individual heat-sensitive transfer recording material having no coloring layer or coloring agent is provided in the individual thermal transfer recording material. A heat-sensitive transfer recording medium, wherein a metal having a crystal structure is internally added. 10. A coloring layer using at least one of a pigment and a dye as a coloring material is provided on a support, and the individual thermal transfer recording material not having the coloring layer or the coloring agent is provided in the individual thermal transfer recording material. A heat-sensitive transfer recording medium having a property of emitting fluorescence upon irradiation with X-rays. 11. A coloring layer using at least one of a pigment and a dye as a coloring material is provided on a support, and the individual heat-sensitive transfer recording material having no coloring layer or coloring agent is provided in the individual thermal transfer recording material. A thermal transfer recording medium, wherein a photochromatic material which is visualized by light irradiation is internally added.