JP3164845B2 - Recording method of rewritable recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is reversibly recorded by light or heat, but a recording method of the erasable recording medium body, which the color recording possible, in particular a color copying or color printer There is an advantage in application to a rewritable color recording sheet for facsimile and a memory card with a rewritable display function.

[0002]

2. Description of the Related Art Conventionally, recording materials used for rewritable recording media include heat mode materials and photon mode materials.

[0003] The heat mode material can be a reversible thermosensitive recording material having light absorption characteristics, and includes a phase change recording material and a magneto-optical recording material. Organic reversible thermosensitive recording materials include a thermosensitive dye-based recording material that reversibly develops and decolors by combining a leuco dye with a developer and a decolorant, and the melting and melting of organic crystal particles in a matrix polymer. A phase change type reversible thermosensitive recording material that utilizes the change in the transparency of particles depending on the coagulation conditions using the solidification behavior, and a liquid crystal polymer such as a cholesteric liquid crystal is used to make use of the thermal behavior of its molecular arrangement to make it transparent. There are ways to change sex.

A phase-change type thermosensitive recording material utilizing the fact that transparency changes depending on coagulation conditions is used to melt fine particles by heat and solidify again, and depending on the conditions, for example, a polycrystalline state, a single crystal state, an amorphous state, or the like. The difference is caused in the transparency caused by the coagulation morphology, and the result is recorded.
This heat-sensitive recording material is disclosed in, for example, JP-A-54-119377.
As disclosed in Japanese Patent Application Laid-Open No. H11-163, the recording medium is composed of a combination of a matrix polymer and the following fusible organic molecules, so that extremely various recording materials can be formed. The fusible organic molecules disclosed herein include aliphatic and aromatic alcohols, carboxylic acids, amines, amides, and halides and sulfides thereof. On the other hand, as the matrix polymer, polyester, polyamide, polyacrylic acid,
Common polymers such as styrene, silicone, polyvinyl chloride, polyvinylidene chloride, and polyacrylonitrile are disclosed. Further, a recording material in which carbon black is further added for light-to-heat conversion and an antioxidant is added for improvement are disclosed in, for example, JP-A-57-82087 and JP-A-57-82088.

[0005]

However, although the above-mentioned prior art discloses fusible organic molecules, matrix polymers and carbon black, there is a problem that multicolor recording cannot be performed.

[0006]

The present invention relates to a reversible thermosensitive recording material having a variable transparency.
New and high quality rewritable
It is an object of the present invention to provide a rewritable recording method which can be widely applied to, for example, a printer, a facsimile recording sheet, a color copier, a memory card with a display function, and the like by using a multi-color and color recording medium.

[0008]

SUMMARY OF THE INVENTION Recording on a recording medium of the present invention
As a method, the recording layer is made transparent by the first heating mode.
After detecting the color and position of the colored layer,
Generates a heating pulse in the second heating mode corresponding to the image signal
The recording layer at the position detected
Achieved by concealing and recording the color of the colored layer
Wear.

[0009]

[0010]

[0011]

The rewritable recording medium of the present invention produces a recording display color by a colored layer, and a recording layer is provided on the colored layer.
Recording is performed by concealment (white turbidity) and visible (transparent) using the two states of the recording layer after the two heating modes. When the recording layer of the rewritable recording medium of the present invention is transparent, the colored layer can be seen because the colored layer is visible, and when the recording layer is opaque, white is displayed because the colored layer is hidden. When the coloring layer is a single color, recording of a single color of a colored color and white is performed, but in a configuration in which the coloring layer is colored of a plurality of colors, recording of a plurality of colors and white can be performed. Using this principle, multi-color recording or color recording is possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a typical embodiment for performing color optical recording on a rewritable recording medium according to the present invention. FIG. 1 shows that a second recording layer 5 is formed on a substrate 1 on which a light absorbing layer 2 is formed. On the recording layer 5, a red portion 4R,
A light-transmissive colored layer 4 divided into three primary colors of light of a green portion 4G and a blue portion 4B in the surface direction of the substrate 1 is formed, and a first recording layer 3 and a surface protective layer 6 are further formed thereon. I have. The light absorbing layer 2 is a layer that absorbs the transmitted light of the coloring layer 4 existing thereon, and may have a complementary color of the hue of the coloring layer 4, but it is generally convenient to use black. The resolution of the image is determined by the resolution of the coloring layer 4.

First, the entire recording layer is made transparent by heating in the first heating mode. The colored layer 4 develops the colors of the red portion 4R, the green portion 4G, and the blue portion 4B. However, since the recording layers 3 and 5 are transparent, the transmitted light is absorbed by the light absorbing layer 2 and the surface protective layer 6 side It looks black when viewed. This is the initial (reset) state before recording. When the color image light is irradiated, the colored layers 4 colored red (R), green (G), and blue (B) absorb light other than their own transmitted light (or reflected light), and the temperature rises. Due to the temperature rise in the second heating mode, the recording layers 3 and 5 in the vicinity of the colored layer become clouded, and the color of the colored layer is hidden. That is, in the portion irradiated with the white light, all three primary colors of the colored layer rise in temperature to absorb light having a wavelength other than their own transmitted light, become white, and become white. Regarding the recording of the color portion, for example, in the case of a portion irradiated with red light, only the red portion 4R of the colored layer does not absorb light, so the recording layer 3 on the red portion 4R is kept transparent. The red light transmitted through the red portion 4R of the colored layer 4 is reflected by the light absorbing layer 2 immediately below the colored layer of the red portion 4R.
And the temperature of the light absorbing layer 2 at this portion rises, and the second recording layer 5 on the light absorbing layer 2 is subjected to a change in the second heating mode.
Becomes cloudy. When viewed from the surface protective layer 6 side, the color of the red portion 4R of the colored layer 4, that is, red, is exhibited. On the other hand, the green portion 4G and the blue portion 4B of the colored layer 4 irradiated with the red light absorb the light, respectively, rise in temperature, become cloudy, and exhibit white. Therefore, the portion irradiated with red light exhibits red.
Green and blue recordings can be formed by the same mechanism when irradiating green light and blue light. On the other hand, in the black portion not irradiated with light, the red portion 4R, the green portion 4G, and the blue portion 4B transmit light as described above, and the transmitted light is absorbed by the light absorbing layer 2 immediately below the colored layer. As a result, it takes on a black color. This first method of the invention is not limited to color copy sheets, but also to overhead projectors.
It can also be used for (OHP) sheets.

FIG. 2 shows a second representative embodiment for performing color printing in the present invention. FIG. 2 shows the light reflection layer 7.
Are formed on the substrate 1 on which red portions 4R, green portions 4G,
A light-transmitting colored layer 4 which is separated into four colors of a blue portion 4B and a black portion 4BK is formed, and a recording layer 3 is further formed thereon.
And a surface protective layer 6 are formed. The configuration in which the light reflection layer 7 is formed is suitable for obtaining a clear image with a large contrast. The recording method for this recording medium is performed as follows. In this recording medium, the recording layer 3 is made transparent in the first heating mode in the same manner as in the first embodiment, and the recording is initially set to the initial (reset) state. The color and position of the colored layer 4 of the recording medium thus initialized are detected by the light detection head 8, and a heating pulse in the second heating mode is generated in the writing thermal head 9 in accordance with the detection signal and the image signal. To make the recording layer 3 opaque and the colored layer 4
This is a method of recording while hiding the color of the image. Here, the colored layer 4
Is added to the recording layer 3 so that when the light detection head 8 detects black, a heating pulse in the second heating mode is generated in the writing thermal head 9 so that the black portion of the recording layer 3 is generated. 4BK is made cloudy. The configuration including the black portion 4BK in the color layer obtained by color separation is suitable for easily reproducing the color of black. This method does not directly reproduce color by irradiating image light as described above, but performs recording through control of a head by an electric signal. Therefore, this method is suitable for facsimile machines, printers, digital copiers and the like.

FIG. 3 shows a third representative embodiment for performing color printing in the present invention. The configuration itself of the recording medium shown in FIG. 3 is the same as that of the first embodiment shown in FIG. The recording method for this recording medium is performed as follows. The recording layers 3 and 5 are made transparent to the recording medium in the first heating mode in the same manner as in the first embodiment, and the recording medium is first set to the initial (reset) state. The color and the position of the colored layer 4 of the recording medium thus initialized are detected by the light detection head 8, and the laser 10 is irradiated in accordance with the detection signal and the image signal to generate a heating pulse in the second heating mode. In this method, the recording layers 3 and 5 are made opaque by generating a corresponding light pulse and heating the coloring layer 4, so that the color of the coloring layer 4 is hidden and recorded. In this case, since the recording medium is black in the initialized state, it is difficult for the light detection head 8 to detect the color of the colored layer. For this reason, it is possible to easily detect the color and position of the colored layer by various methods such as forming a pattern so that the light absorbing layer 2 can easily detect the color, or storing the color position in the colored layer 4 in advance. is there.

On the other hand, as another method, at the time of initialization, the recording layer 3 is made transparent within the two recording layers 3 and 5 so that the recording layer 5 becomes cloudy, and the color and the position of the coloring layer 4 are detected by a light detection head. 8, there is a method for easy detection. In this case, the recording layer 5 existing under the coloring layer 4 is whitened, and the laser 10
Variable heating mode. The color unnecessary for the image causes the recording layer 3 existing on the coloring layer 4 to become cloudy with a light pulse corresponding to the second heating mode, and when recording black, the recording layer 5 is formed with a light pulse corresponding to the first heating mode. Is made transparent.
In the configuration using the laser 10, it is also possible to control the temperature difference between the two recording layers 3 and 5 by focusing the laser 10 on either the recording layer 3 or the recording layer 5. The method of the third embodiment is a recording method suitable for a facsimile, a printer, a digital copying machine, and the like, like the second recording method.

1 to 3, the colored layer 4 is red,
Although the form divided into the three primary colors of green and blue has been described, it is a matter of course that recording can be performed by the same operation even in the case of single-color or multi-color recording.

As described above, according to the recording method of the present invention,
In any case, rewritable recording is possible, and the degree of white turbidity can be controlled by the degree of the temperature of the second heating mode, and recording with a different concealment force can be performed. Therefore, halftone recording is also possible, and rewritable by a simple configuration. Record is possible,
It can support multicolor recording and color recording.

In the present invention, the plurality of hue portions of the colored layer 4 decomposed in the plane direction of the substrate are desirably one of a stripe shape, a mosaic shape, and a dot matrix shape. A pattern that can perform signal processing is more desirable in terms of the reading speed. Such a recording layer 4 can be formed by, for example, a normal printing method such as a screen printing method or a gravure printing method, a method of sequentially dyeing a plurality of hues on a matrix that is easily dyed such as gelatin, a method of dyeing a plurality of colors. The resist can be formed by an ordinary method such as a photoprocess method in which printing, pattern exposure and development are sequentially repeated, or an electrodeposition method in which a colorant charged in an electrolytic solution is electroplated. As described above, since the resolution of the recording medium of the present invention is determined by the colored layer 4, it is preferable that the plurality of divided hue portions of the colored layer 4 be as small as possible. The coloring layer 4 divided into a plurality of hues at a pitch can be formed.

Examples of the material provided for the colored layer 4 of the present invention include organic or inorganic substances such as a colored pigment, a thermoplastic resin or a thermosetting resin colored with a dye or a pigment, glass, and the like. . However, when performing multi-color recording by light irradiation such as color copying or the like, a light-transmissive colored layer 4 is required.

The substrate 1 used in the present invention includes, for example, glass, metal, polymer film and the like, and an appropriate material can be selected according to the use of the recording medium of the present invention.

As the recording material used for the recording layers 3 and 5 in the present invention, a reversible thermosensitive recording material can be used. The reversible thermosensitive recording materials include: 1) a phase change type material utilizing the melting and solidification behavior of organic crystal particles in a matrix polymer and utilizing the change in transparency of the particles depending on solidification conditions; 3) those that repeat transparency and opacity according to the size of the crystalline domain of the conductive polymer, 3) those that utilize the crystalline-amorphous transition, 4) those that are compatible or incompatible with the composition of two or more materials, 5) Some use the thermal behavior of molecular alignment by polymer liquid crystals.

The recording layers 3 and 5 of the present invention need to have excellent contrast, excellent transparency and white turbidity, and have the above-mentioned 1) particularly in view of the response speed and low cost. The use of a phase change thermosensitive recording material is suitable. Therefore, the phase-change type thermosensitive recording material will be described below, but it goes without saying that the recording layer 3 or 5 provided in the recording medium of the present invention is not limited to the phase-change type thermosensitive recording material.

This phase-change type thermosensitive recording material is composed of a combination of a matrix polymer and the following fusible organic molecules, as disclosed in, for example, JP-A-54-119377. Can be configured.
The fusible organic molecules disclosed herein include aliphatic and aromatic alcohols, carboxylic acids, amines, amides, and halides and sulfides thereof. On the other hand, as the matrix polymer, general polymers such as polyester, polyamide, polyacrylic acid, styrene, silicone, polyvinyl chloride, polyvinylidene chloride, and polyacrylonitrile are disclosed. Further, a recording material in which carbon black is further added for light-to-heat conversion and an antioxidant is added for improvement thereof are disclosed in, for example, JP-A-57-82087 and 57-82088.

In the case where the recording layers 3 and 5 of the present invention are phase change type thermosensitive recording materials, the above-mentioned fusible organic molecules are disclosed, but among them, a composite material of crystalline organic molecules and a matrix polymer is used. It is preferable to use a molecule having a hydrogen bonding group, especially in consideration of the crystallinity of the crystalline organic molecule. Among the hydrogen bonding groups, an organic molecule having at least one of a carboxyl group, a hydroxyxyl group, an amino group, and an amide group is preferable because of high crystal growth, and has a melting point of 60 to 120 ° C. The use of is desirable because the heat energy or light intensity required for recording or erasing can be reduced. In order to adjust the melting point of these molecules, these crystalline organic molecules are further separated from, for example, higher alcohols, fatty acids, alkylamines, oxycarboxylic acids, dicarboxylic acids, diamines, dialkylene glycols, etc. by forming eutectics or complexes. Alternatively, a crystalline organic molecule having a desired melting point can be formed.

On the other hand, the matrix polymer used for the recording layer 3 or 5 of the present invention includes polyester, polyacrylate, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, cellulose acetate, polyvinyl butyral, polystyrene, styrene / butadiene. A transparent polymer such as a copolymer may be mentioned, but a transparent matrix polymer partially containing a hydrogen bonding group is suitable in terms of controlling compatibility.
As specific examples, adhesive (OH group-containing) polyester,
There are partially saponified vinyl acetate / vinyl chloride copolymer, polyamide, polyurethane, thermoplastic phenol resin, vinyl alcohol copolymer, acrylic acid copolymer, acrylamide copolymer, maleic acid copolymer and the like. In addition, it is natural that a plasticizer is used in combination therewith as appropriate.

In the recording layers 3 and 5 of the present invention made of this phase-change type thermosensitive recording material, when the crystalline organic molecules in the recording layers 3 and 5 are heated to near the melting point and cooled, the solidified crystalline organic molecules become transparent. When it is melted at a higher temperature and then cooled, the solidified crystalline organic molecules become cloudy. In the present invention, the heating which becomes transparent after cooling and solidifying after melting is called a first heating mode, and the heating which becomes cloudy is called a second heating mode. The reason for this phenomenon is unclear, but when cooled after heating in the first heating mode, the crystals solidify in the presence of crystal nuclei, causing large crystals to grow and become transparent, while the second heating mode. When cooled after heating by a negative electrode, the crystalline organic molecules are cooled to a melting point or lower in a supercooled state, and are therefore supposed to crystallize at once and become fine crystals and become cloudy.

Further, it goes without saying that additives such as an antioxidant, an ultraviolet absorber or a plasticizer may be added to the recording layer 3 or 5 of the present invention in a usual manner.

The amount of the crystalline organic molecules constituting the recording layer 3 or 5 relative to the matrix polymer is 5-5.
Although it can be added in a range of 0%, addition of 15 to 40% is desirable. When the ratio of the crystalline organic molecules is higher than this, the binding force is weakened, and it is difficult to form a uniform coating as the recording layer 3 or 5. Conversely, when the ratio of the matrix polymer increases, the amount of crystalline organic molecules decreases, so that opacity is difficult and the recording contrast deteriorates.

As described above, the recording layer 3 or 5 of the recording medium of the present invention
In the above, the case where a phase-change thermosensitive recording material is used has been described. Of course, a possible recording medium can be formed.

Although the surface protective layer 6 in the present invention is not necessarily required, it is generally formed by an ordinary method for the purpose of preventing the recording layer 3 from being scratched or dusted. Is practical. In addition, if the wear-resistant surface protective layer 6 is provided, a recording medium with little deterioration over time even with contact with the thermal head and high repetitive durability can be formed. Light scattering due to scratches or the like can be prevented.

Next, the present invention will be described with reference to specific examples. (Example 1) In order to constitute the recording material of the recording layers 3 and 5, hydroxystearic acid 4 was used as a crystalline organic molecule.
g, a hindered phenolic antioxidant 0.1 g as an additive, and vinyl chloride
6 g of a vinyl acetate / acrylamide copolymer was dissolved in 100 ml of tetrahydrofuran to prepare a recording material solution. As a black light absorbing layer 2, a 0.2 mm-thick polyester sheet coated with carbon black having a thickness of 15 μm on the entire surface is used as a substrate 1. On this light absorbing layer 2, the recording material solution is used. It was formed with a thickness of 30 μm. On the recording layer 5, red, green,
A 5 μm-thick colored layer 4 divided into three primary colors of blue was formed by screen printing. Further, using this recording material solution, a recording layer 3 having a thickness of 30 μm was formed on the coloring layer 4. Further, as a surface protective layer 6, a UV-curable acrylic resin prepolymer was coated by a bar coating method to a thickness of 20 μm, and then cured by irradiating ultraviolet rays.

The recording medium thus formed is melted and cooled by a heating roller at 80 ° C. as a first heating mode to make the recording layers 3 and 5 transparent.
(Reset) state. When this recording medium was irradiated with light of a color image and writing was performed, a clear color image was obtained. Furthermore, after erasing, the light of the color image was irradiated again to form a color image repeatedly. The transparency temperature range of this recording medium is about 70 to 80 ° C.
Met. When the life characteristics were measured repeatedly, it was endured 150 times.

Example 2 3 g of behenic acid as a crystalline organic molecule of a recording material, 0.1 g of a phenolic antioxidant as an additive, and 6 g of a vinyl chloride / vinyl acetate / acrylamide copolymer as a transparent matrix polymer Was dissolved in 100 ml of tetrahydrofuran to obtain a recording material solution. As a white light reflecting layer 7, a 0.2 mm-thick polyester sheet coated with a 15 μm-thick white paint was used as the substrate 1, and 10% of the white light reflecting layer 7 as shown in FIG.
Red, green, blue and black 4 stripes at 0 μm pitch
A colored layer 4 having a thickness of 5 μm and separated into colors was formed by screen printing. Further, using the above recording material solution,
The recording layer 3 was formed with a thickness of 30 μm. Further, a UV-curable acrylic resin prepolymer was coated as a surface protective layer 6 by a bar coating method to a thickness of 25 μm, and then cured by irradiating ultraviolet rays. The transparency temperature range of the rewritable color recording medium thus obtained was about 80 to 90 ° C. This recording medium is subjected to a melting / cooling process by a 90 ° C. heat roller as a first heating mode to make the recording layer 3 transparent,
First, an initial (reset) state of recording was set. The color and the position of the colored layer 4 of the recording medium thus initialized are detected by the light detection head 8, and the write thermal head 9 is set to the first heating mode in the second heating mode in accordance with the detection signal and the color image signal.
A heating pulse of 30 ° C. is generated to make the recording layer 3 cloudy,
A clear color recorded image was obtained. Further, when the repetition characteristics were measured, it was endured 110 times.

Example 3 A black light absorbing layer 2 having a thickness of 15 μm was formed on a polyester sheet substrate 1 having a thickness of 0.2 mm.
After coating m of carbon black on the entire surface except for the end of the substrate 1, a recording medium similar to that of Example 1 was formed. The end of this sheet is used for detecting the color of the striped colored layer. The recording medium thus formed is subjected to a melting / cooling process by a heat roller at 80 ° C. as a first heating mode to make the recording layers 3 and 5 transparent in the same manner as in Example 1 above, and first to an initial (reset) state of recording. And The color and position of the colored layer 4 of the recording medium thus initialized are detected by the light detection head 8, and the laser 10 generates a second heating mode light pulse in accordance with the detection signal and the color image signal. The recording layer was made cloudy and the color of the colored layer 4 was hidden to record. Thus, a clear color recorded image was obtained. Further, when the repetition characteristics were measured, it was endured 210 times.

Example 4 A recording medium having the same structure as that of Example 1 was heated from the back side with a heat roller at the time of initialization, so that the first recording layer 3 was made transparent and the second recording layer 5 was made cloudy. .
With respect to the initialized recording medium, the color and the position of the coloring layer 4 are detected by the photodetecting head 8, and the color unnecessary for the image is changed by the light pulse of the laser 10 corresponding to the second heating mode. Was opaque and hidden. The black portion was irradiated with a weak light pulse corresponding to the first heating mode to make the second recording layer 5 transparent. Using this recording medium, application to a laser printer was studied.

[0037]

As described above, the rewritable recording medium of the present invention forms a colored layer having a plurality of hues on a substrate and forms a transparent layer on the substrate by heating and cooling processes in two heating modes. -It is composed of a recording medium provided with a recording layer that forms two states of white turbidity, so that an easily rewritable image can be obtained, and it is possible to cope with multicolor recording such as color. The present invention can perform not only color copying by irradiating color image light but also color recording through control of a head by an electric signal, and is of industrial value applicable to facsimile machines, printers, digital copying machines, and the like. It is a great thing.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part showing a configuration of a representative embodiment for performing color optical recording on a rewritable recording medium of the present invention.

FIG. 2 is an enlarged sectional view of a main part showing a configuration of a second representative embodiment for performing color recording on a rewritable recording medium of the present invention.

FIG. 3 is an enlarged sectional view of a main part showing a configuration of a third representative embodiment for performing color recording on a rewritable recording medium of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Light absorption layer 3 Recording layer 4 Colored layer 4R Red part 4G Green part 4B Blue part 4BK Black part 5 Recording layer 6 Surface protection layer 7 Light reflection layer 8 Photodetection head 9 Writing thermal head 10 Laser

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-576 (JP, A) JP-A 1-172896 (JP, A) JP-A 64-78880 (JP, A) JP-A 64-64 26493 (JP, A)

Claims (2)

(57) [Claims] A light absorbing layer provided on a substrate;
Recorded equipped with divided into a plurality of hues in the surface direction of the substrate provided on the layer coloring layer, and a recording layer to form a two-state transparent-opaque, respectively, by two heating modes provided on the colored layer the medium was clarified the recording layer by the first heating mode, the light absorption color and position of the colored layer
Detecting by the pattern formed in the layer, generating a heating pulse of the second heating mode corresponding to the detection signal of the color and the position and the image signal, the recording layer at the position becomes cloudy, the color of the coloring layer A recording method for a rewritable recording medium, wherein the recording is performed while concealing the recording. 2. The recording method for a rewritable recording medium according to claim 1, wherein the heating pulse is a pulse by a thermal head or a laser.