JP2010059288A - Photochromic composition, image display medium and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-color image display medium and a multi-color imaging method of a rewritable type which can form/erase an image by light, with excellent image retentivity. <P>SOLUTION: A photochromic composition contains a photochromic compound expressed by general formula (1) and a long-chain alkyl compound, provided that R<SB>1</SB>and R<SB>2</SB>are each independently an ≥18C long-chain hydrocarbon; Z is absent or -CH<SB>2</SB>OCO- or the like; X represents O, S or the like; and R<SB>3</SB>to R<SB>7</SB>each represent hydrogen or the like. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photochromic composition, an image display medium, and an image forming and erasing apparatus. More specifically, the present invention relates to a photochromic compound capable of repeatedly forming an image by light irradiation and heat treatment, an image display medium, and image formation and The present invention relates to an erasing device.

As a method for forming a color image using a photochromic compound, for example, in Patent Document 1, a photochromic property that develops yellow-orange by 254 nm ultraviolet light irradiation, red by 313 nm ultraviolet light irradiation, and bluish purple by 365 nm ultraviolet light irradiation. A method of mixing three kinds of diarylethene compounds and irradiating ultraviolet light of each wavelength has been proposed.
In order to form a full-color image, it is necessary to control the extinction / color development of three or more kinds of photochromic compounds that develop three primary colors (blue, green, red or yellow, magenta, and cyan) with light. Therefore, it is necessary to select whether or not each material is colored depending on three types of ultraviolet light wavelength regions, that is, three or more types of photochromic compounds that do not overlap in the absorption band in the ultraviolet region are required. The three primary colors must be exhibited in the colored state, but no such compound system is actually found.
For practical use, it is necessary to consider not only the color development characteristics but also the repeated durability and heat / humidity stability, and it is very difficult to develop a material satisfying all of these.

Further, in Patent Document 2, after three types of photochromic fulgide compounds exhibiting yellow, magenta, and cyan in a colored state are developed, all the photochromic compounds are colored with 366 nm ultraviolet light, and then white light is transmitted through the color positive film. There has been proposed a method of obtaining a color image by selectively erasing each photochromic fulgide compound as necessary by irradiation.
Although this method has the advantage that only one type of ultraviolet light source can be used, it requires a color positive film for the image to be formed, and it is not practical to prepare it each time. Not suitable for use in image output.
Further, the image formed in this way is gradually discolored by the illumination light and the image is lost.

In addition, when a photochromic compound is used for an image display medium, it is one of the problems that must be overcome to maintain a formed image for a long time under visible light.
So far, preservation of the color development state of photochromic compounds has been studied.
The use is an optical recording material, but Patent Document 3 and Patent Document 4 associate the color development state (photomerocyanine) of the spiropyran compound to enhance the storage stability.
However, spiropyran compounds generally tend to be unable to ensure sufficient strength in various durability such as repeated durability of color development and decoloration and storage stability of the color erased state and color developed state.

Japanese Patent Laid-Open No. 5-271649 JP 7-199401 A Japanese Patent Laid-Open No. 62-147455 JP-A-62-146979

  The present invention has been made in view of the above-described state of the art and problems, can form an image by light, can be erased by light or heat treatment, and can be repeatedly formed and erased. It is another object of the present invention to provide a rewritable multicolor image display medium and a multicolor image method that are excellent in image retention and excellent in image retention.

That is, the said subject is solved by following (1)-(13) of this invention.
(1) “A photochromic composition comprising a photochromic compound represented by the following general formula (1) and a long-chain alkyl compound.

（ただし、Ｒ_１、Ｒ_２、は独立して炭素数１８以上の長鎖炭化水素基である。Ｚは存在しないか、あるいは−ＣＨ_２ＯＣＯ−、−ＮＨＣＯ−、−Ｏ−、−ＯＣＯ−の中から選択される１つである。ＸはＯ、Ｓ、Ｃ（ＣＨ_３）_２のいずれかである。Ｒ_３〜Ｒ_７は独立して水素であるかまたは置換基であり、そのうちの少なくとも一つは電子求引基であり、Ｒ_９〜Ｒ_１２は独立して水素であるかまたは置換基であり、そのうちの少なくとも一つは電子供与基である。Ｒ_８は水素であるかまたは置換基である。）」、
（２）「前記第（１）項に記載のフォトクロミック組成物による表示層が支持基体上に形成されていることを特徴とする画像表示媒体」、
（３）「会合状態における色相が異なる２種以上のフォトクロミック化合物を表示層中に含むことを特徴とする前記第（２）項に記載の画像表示媒体」、
（４）「会合状態においてイエローの色相を示す第１のフォトクロミック化合物と、マゼンタの色相を示す第２のフォトクロミック化合物と、シアンの色相を示す第３のフォトクロミック化合物とを表示層中に含むことを特徴とする前記第（２）項に記載の画像表示媒体」、
（５）「前記表示層が、前記第１のフォトクロミック化合物のみを含む表示層と、前記第２のフォトクロミック化合物のみを含む表示層と、前記第３のフォトクロミック化合物のみを含む表示層が積層された構造であることを特徴とする前記第（４）項に記載の画像表示媒体」、
（６）「前記第（２）項乃至第（５）項のいずれかに記載の画像表示媒体に対し、部分的に紫外光を照射する紫外光照射手段と、発色安定化に必要な所定温度に表示層を昇温する加熱手段とを備えることを特徴とする画像形成装置」、
（７）「前記第（２）項乃至第（５）項のいずれかに記載の表示層が形成された光ディスクを回転駆動する回転駆動手段と、前記光ディスクレーベル記録面に部分的に紫外光を照射する紫外光照射手段と、発色安定化に必要な所定温度に昇温する加熱手段と、を備えることを特徴とする画像形成装置」、
（８）「前記第（２）項乃至第（５）項のいずれかに記載の画像表示媒体に対し、部分的に紫外光を照射する紫外光照射手段と、発色安定化に必要な所定温度に表示層を昇温する第１の加熱手段と、消色に必要な所定温度に表示層を昇温する第２の加熱手段とを備えることを特徴とする画像形成装置」、
（９）「前記第（２）項乃至第（５）項のいずれかに記載の表示層が形成された光ディスクを回転駆動する回転駆動手段と、前記光ディスクレーベル記録面の表示層に部分的に紫外光を照射する紫外光照射手段と、発色安定化に必要な所定温度に表示層を昇温する第１の加熱手段と、消色に必要な所定温度に表示層を昇温する第２の加熱手段とを備えることを特徴とする画像形成装置」、
（１０）「前記第（２）項乃至第（５）項のいずれかに記載の画像表示媒体に対し、表示層に紫外光を照射する紫外光照射手段と、発色状態における各々のフォトクロミック化合物の極大吸収波長に対応した波長域の可視光を照射する可視光照射手段と、発色安定化に必要な所定温度に表示層を昇温する加熱手段とを備えることを特徴とする画像形成装置」、
（１１）「前記第（２）項乃至第（５）項のいずれかに記載の表示層が形成された光ディスクを回転駆動する回転駆動手段と、前記光ディスクレーベル記録面の表示層に紫外光を照射する紫外光照射手段と、発色安定化に発色状態における各々のフォトクロミック化合物の極大吸収波長に対応した波長域の可視光を照射する可視光照射手段と、消色に必要な所定温度に表示層を昇温する加熱手段とを備えることを特徴とする画像形成装置」、
（１２）「前記第（２）項乃至第（５）項のいずれかに記載の画像表示媒体に対し、表示層に紫外光を照射する紫外光照射手段と、発色状態における各々のフォトクロミック化合物の極大吸収波長に対応した波長域の可視光を照射する可視光照射手段と、発色安定化に必要な所定温度に表示層を昇温する第１の加熱手段と、消色に必要な所定温度に表示層を昇温する第２加熱手段とを備えることを特徴とする画像形成装置」、
（１３）「前記第（２）項乃至第（５）項のいずれかに記載の表示層が形成された光ディスクを回転駆動する回転駆動手段と、前記光ディスクレーベル記録面の表示層に紫外光を照射する紫外光照射手段と、発色状態における各々のフォトクロミック化合物の極大吸収波長に対応した波長域の可視光を照射する可視光照射手段と、発色安定化に必要な所定温度に表示層を昇温する第１の加熱手段と、消色に必要な所定温度に表示層を昇温する第２の加熱手段とを備えることを特徴とする画像形成装置」。

(However, R ₁ and R ₂ are each independently a long-chain hydrocarbon group having 18 or more carbon atoms. Z does not exist, or —CH ₂ OCO—, —NHCO—, —O—, —OCO— X is O, S, or C (CH ₃ ) _2. R _{3 to} R ₇ are independently hydrogen or a substituent, of which At least one is an electron withdrawing group, R _{9 to} R ₁₂ are independently hydrogen or a substituent, at least one of which is an electron donating group, R ₈ is hydrogen or Is a substituent.) ",
(2) "Image display medium, wherein a display layer made of the photochromic composition according to item (1) is formed on a support substrate",
(3) “Image display medium according to item (2), wherein the display layer contains two or more photochromic compounds having different hues in an associated state”;
(4) The display layer includes a first photochromic compound exhibiting a yellow hue in an associated state, a second photochromic compound exhibiting a magenta hue, and a third photochromic compound exhibiting a cyan hue. “The image display medium according to item (2)”,
(5) “The display layer includes a display layer including only the first photochromic compound, a display layer including only the second photochromic compound, and a display layer including only the third photochromic compound. The image display medium according to item (4), which has a structure ”,
(6) “Ultraviolet light irradiation means for partially irradiating the image display medium according to any one of (2) to (5) with ultraviolet light, and a predetermined temperature required for color stabilization An image forming apparatus comprising a heating means for raising the temperature of the display layer ”,
(7) “Rotation driving means for rotating the optical disk on which the display layer according to any one of (2) to (5) is formed, and ultraviolet light is partially applied to the optical disk label recording surface. An image forming apparatus comprising: an ultraviolet irradiation means for irradiating; and a heating means for raising the temperature to a predetermined temperature necessary for color stabilization ”
(8) “Ultraviolet light irradiation means for partially irradiating the image display medium according to any one of (2) to (5) with ultraviolet light, and a predetermined temperature required for color stabilization An image forming apparatus comprising: a first heating unit that raises the temperature of the display layer; and a second heating unit that raises the temperature of the display layer to a predetermined temperature necessary for decoloring.
(9) “Rotation driving means for rotationally driving the optical disk on which the display layer according to any one of (2) to (5) is formed, and partly on the display layer of the optical disk label recording surface Ultraviolet light irradiation means for irradiating ultraviolet light, first heating means for raising the temperature of the display layer to a predetermined temperature necessary for color stabilization, and second temperature for raising the display layer to a predetermined temperature required for decolorization An image forming apparatus comprising a heating unit ",
(10) “Ultraviolet light irradiation means for irradiating the display layer with ultraviolet light on the image display medium according to any one of (2) to (5), and each photochromic compound in a colored state An image forming apparatus comprising: a visible light irradiating unit configured to irradiate visible light in a wavelength region corresponding to the maximum absorption wavelength; and a heating unit configured to raise the display layer to a predetermined temperature necessary for color stabilization.
(11) “Rotation driving means for rotating the optical disk on which the display layer according to any one of (2) to (5) is formed, and ultraviolet light is applied to the display layer of the optical disk label recording surface. Ultraviolet light irradiation means for irradiating, visible light irradiation means for irradiating visible light in a wavelength range corresponding to the maximum absorption wavelength of each photochromic compound in a colored state for color stabilization, and a display layer at a predetermined temperature required for decoloring An image forming apparatus comprising:
(12) “Ultraviolet light irradiation means for irradiating the display layer with ultraviolet light on the image display medium according to any one of the above items (2) to (5); and each of the photochromic compounds in a colored state. Visible light irradiating means for irradiating visible light in a wavelength region corresponding to the maximum absorption wavelength, first heating means for raising the display layer to a predetermined temperature necessary for color stabilization, and a predetermined temperature necessary for decoloring An image forming apparatus comprising: a second heating unit configured to raise the temperature of the display layer ”;
(13) “Rotation driving means for rotationally driving the optical disk on which the display layer according to any one of (2) to (5) is formed, and ultraviolet light is applied to the display layer on the optical disk label recording surface. Ultraviolet light irradiation means to irradiate, visible light irradiation means to irradiate visible light in a wavelength range corresponding to the maximum absorption wavelength of each photochromic compound in the colored state, and the temperature of the display layer to a predetermined temperature required for color stabilization An image forming apparatus comprising: a first heating unit configured to perform heating, and a second heating unit configured to raise the temperature of the display layer to a predetermined temperature necessary for decoloring ”.

According to the present invention, it is possible to obtain an image forming material and an image display medium that are excellent in storage stability and repetitive durability against rewriting, and are capable of imparting sufficient stability to light, and further enable full color display.
Furthermore, according to the present invention, it is excellent in storage stability and repetitive durability against rewriting, a plurality of colors having different hues can be displayed, and color retention of a formed image can be improved.
Furthermore, according to the present invention, in addition to the above effects, an appropriate laminated structure without mixed fat stains of materials between the display layers can be obtained, and appropriate color display can be performed for each display layer.
Furthermore, according to the present invention, a monochrome image or a multicolor image can be formed on a medium including a sheet mold, which has excellent storage stability and repeated durability against rewriting and can provide sufficient stability to light. And an erasable device is obtained.
Furthermore, according to the present invention, formation and erasure of a monochrome image or a multicolor image, which is excellent in storage stability and repetitive durability against rewriting and capable of imparting sufficient stability to light, on an optical disk type medium. A device capable of achieving the above is obtained.

Embodiments of the present invention will be described in detail with reference to the drawings.
In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated in order to avoid duplication of description.
First, a basic mechanism of an image display medium in which a display layer containing a photochromic compound is formed on a substrate and a method of forming a color image by light irradiation on the display layer will be described.

FIG. 1 is a schematic diagram showing a configuration of an image display medium (1) used in the present invention.
In this image display medium (1), a display layer containing two or more types of photochromic compounds having different maximum absorption wavelengths in the colored state, that is, different colors recognized in the colored state, is formed on the support substrate (10). The
The structure shown in FIG. 1 is formed by laminating display layers (11), (12), and (13) containing three types of photochromic compounds having different maximum absorption wavelengths.
The display layer (11) containing the first photochromic compound has the characteristics of the maximum absorption wavelength shown in FIG. 2 (A), and the display layer (12) containing the second photochromic compound is shown in FIG. The display layer (13) having the maximum absorption wavelength characteristic indicated by ()) and including the third photochromic compound is composed of each having the maximum absorption wavelength characteristic indicated by (C) in FIG.

In this, after coloring all kinds of photochromic compounds contained in the display layer by ultraviolet light irradiation, in the wavelength range corresponding to the visible absorption band of each colored photochromic compound (wavelength range near the maximum absorption wavelength) A desired color image is obtained by irradiating each predetermined region with light and selectively decoloring a corresponding photochromic compound.
In the example shown in FIG. 1, the first display layer (11) is decolored with respect to light of wavelength A, and the second display layer (12) is decolored with respect to light of wavelength B, The third display layer (13) is decolored with respect to light of wavelength C.

More specifically, the fact that the maximum absorption wavelength in the colored state is different means that the recognized color is different, and this maximum absorption wavelength only needs to be set according to the color to be used for display. In addition, the type of the photochromic compound may be set corresponding to the number of colors desired for display.
By using photochromic compounds in which the hues in the colored state are yellow, magenta, and cyan, respectively, three primary colors for color display are formed.For example, by adjusting the degree of decoloration of each photochromic compound in the visible light irradiation step, It becomes possible to control the density of the color obtained by the photochromic compound, and the above-described image display method enables multicolor display with a wide color reproduction range.

The above describes the case where an image is formed on an image display medium composed of a display layer containing two or more types of photochromic compounds having different maximum absorption wavelengths in a colored state.
When an image display medium consisting of a display layer containing only one type of photochromic compound is targeted, a so-called monochrome image having a single color hue and a different density is formed. The basic method of forming an image by controlling the degree of color development of the photochromic compound contained is the same as in the case of forming a color image.
In addition, even when the photochromic compound contained in the display layer is one type or when there are two or more types having different maximum absorption wavelengths in the colored state, the photochromic compound is in a predetermined region with respect to the state where all the photochromic compounds are decolored. A monochrome image can be formed by irradiating ultraviolet light to cause color development.

  The present invention can form a color image by light irradiation based on an image display medium having a display layer containing the photochromic compound described above formed on a substrate and a method of forming an image by light irradiation on the display medium, In addition, the present invention has been obtained as a result of studying an image display medium and an image forming method excellent in practical use in which an image can be rewritten and the formed image has sufficient stability to light.

Hereinafter, the present invention will be described in more detail.
One of the features of the present invention is to constitute a photochromic composition containing a photochromic compound represented by the following general formula (1) and a long-chain alkyl compound.

（ただし、Ｒ_１、Ｒ_２、は独立して炭素数１８以上の長鎖炭化水素基である。Ｚは存在しないか、あるいは−ＣＨ_２ＯＣＯ−、−ＮＨＣＯ−、−Ｏ−、−ＯＣＯ−の中から選択される１つである。ＸはＯ，Ｓ，Ｃ（ＣＨ_３）_２のいずれかである。Ｒ_３〜Ｒ_７は独立して水素であるかまたは置換基であり、そのうちの少なくとも一つは電子求引基であり、Ｒ_９〜Ｒ_１２は独立して水素であるかまたは置換基であり、そのうちの少なくとも一つは電子供与基である。Ｒ_８は水素であるかまたは置換基である。）

(However, R ₁ and R ₂ are each independently a long-chain hydrocarbon group having 18 or more carbon atoms. Z does not exist, or —CH ₂ OCO—, —NHCO—, —O—, —OCO— X is one of O, S, and C (CH ₃ ) _2. R _{3 to} R ₇ are independently hydrogen or a substituent, of which At least one is an electron withdrawing group, R _{9 to} R ₁₂ are independently hydrogen or a substituent, at least one of which is an electron donating group, R ₈ is hydrogen or It is a substituent.)

[Spirooxazine-based photochromic compounds]
The spirooxazine photochromic compound represented by the general formula (1) changes its color from a spiro structure to a planar structure when irradiated with ultraviolet light, forms a stable association state by heating, and is irradiated with visible light. Discoloration will not occur.
Compared with the photochromic compound reported well conventionally, the photochromic compound of the general formula (1) shown here has two long-chain structures, an electron withdrawing group, and an electron donating group.
By introducing an electron donating group into any one of R _{9 to} R ₁₂ and an electron withdrawing group into any one of R _{3 to} R ₇ , the spirooxazine in a colored state can easily take an ionic structure. The colored molecules are likely to form an associated state due to the interaction of the ions.

Examples of the electron withdrawing group for R _{3 to} R ₇ include a halogen atom, an aldehyde group, an ester group, a carboxylic acid group, an acyl group, a ketone group, a sulfonic acid group, a cyano group, and a nitro group.
Examples of the electron donating group for R _{9 to} R ₁₂ include an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an amide group, a hydroxyl group, an amino group, and a heterocyclic ring.

In the general formula (1), Z does not exist or is one selected from —CH ₂ OCO—, —NHCO—, —O—, —OCO—, and when Z does not exist, R ₂ Is directly bound to the photochromic compound.

Regarding the length of the long chain structure of R ₁ and R _{2 in} the general formula (1), when any of the two long chain structures is shorter than 18, the association state cannot be maintained for a long period of time. Therefore, the number of carbon atoms in the two long chains is preferably 18 or more.
On the other hand, the upper limit of the length is not particularly limited, but if it is too long, the solubility in a solvent tends to be impaired.

  Another feature of the present invention is that the display layer of the image display medium includes two or more photochromic compounds having different hues in an associated state.

  Furthermore, another feature of the present invention is that a display layer containing two or more photochromic compounds represented by the general formula (1) and a long-chain alkyl compound having different maximum absorption wavelengths in an associated state is formed on a support substrate. Thus, the image display medium is configured.

  Thus, by using two or more kinds of photochromic compounds represented by the general formula (1) having different maximum absorption wavelengths in the associated state, a plurality of colors having different hues can be displayed.

Further, another feature of the present invention is that the display layer comprises a photochromic compound in which the hue in the associated state is yellow, a photochromic compound in which the hue in the associated state is magenta, and a photochromic compound in which the hue in the associated state is cyan. It is to contain everything.
As a result, the three primary colors necessary for color display are formed, and a full color image can be formed by controlling and combining the respective photochromic compound erasing and decoloring states.
As described above, the photochromic compound represented by the general formula (1) changes its color to a merocyanine structure upon irradiation with ultraviolet light, forms a stable association state upon heating, and disappears even when irradiated with visible light. Although it does not occur, the hue changes slightly because the absorption characteristics change before and after the formation of the associated state. Considering this, it is necessary to set the photochromic compound by paying attention to the hue in the state in which the association state is formed.

In the association state of the photochromic compounds, three primary colors of yellow, magenta, and cyan are configured, so that multicolor display is possible.
As the photochromic compound represented by the general formula (1) in which the hue in the association state is yellow, for example, 8′-bromo-5-methoxy-1-octadecyl-5′-docosanate spiro [2H-benzo [d] oxazole -2,3 '-[3H] naphtho [2,1-b] [1,4] oxazine] or 8'-bromo-1,3-dihydro-3,3-dimethyl-5-dimethylamino-1- And octadecyl-5′-docosanoyloxymethyl spiro [2H-indole-2,3 ′-[3H] naphtho [2,1-b] [1,4] oxazine].

  Examples of the photochromic compound represented by the general formula (1) in which the hue in the association state indicates magenta include, for example, 8′-bromo-1,3-dihydro-3,3-dimethyl-5-methoxy-1-octadecyl-5 ′. -Docosanoyloxymethyl spiro [2H-indole-2,3 '-[3H] naphtho [2,1-b] [1,4] oxazine] or 8'-bromo-1,3-dihydro-3,3 5-trimethyl-1-octadecyl-5′-docosaciloxyspiro [2H-indole-2,3 ′-[3H] naphtho [2,1-b] [1,4] oxazine].

  As the photochromic compound represented by the general formula (1) in which the hue in the association state is cyan, for example, 8′-cyano-1,3-dihydro-3,3-dimethyl-5-methoxy-1-octadecyl-5′- Docosanoyloxymethyl spiro [2H-indole-2,3 '-[3H] naphtho [2,1-b] [1,4] oxazine] or 1,3-dihydro-3,3-dimethyl-8'-nitro -1-octadecyl-5-phenyl-5′-docosanoyloxymethylspiro [2H-indole-2,3 ′-[3H] naphtho [2,1-b] [1,4] oxazine] or 5-methoxy- 8′-nitro-1-octadecyl-5′-docosanamide spiro [2H-benzo [d] thiazole-2,3 ′-[3H] naphtho [2,1-b] [1,4] oxa Down], and the like.

[Long-chain alkyl compounds]
It has been confirmed as an experimental result that a long-chain alkyl compound improves the efficiency of association formation of a photochromic compound in a polymer medium.
The long-chain alkyl structure preferably has 12 or more carbon atoms in order to control cohesion between molecules. For example, n-hexadecane, n-pentadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-docosan and the like can be mentioned.
In addition, long-chain alkyl compounds with ester bonds can be used as candidates for other long-chain alkyl compounds. It has been confirmed that a good association state can be formed even with methyl stearate.

[Other materials]
In addition to photochromic compounds and long-chain alkyl compounds, the materials constituting the display layer include binder materials, but they do not adversely affect the photochromic function of the photochromic compounds and are compatible with the photochromic compounds and long-chain alkyl compounds. It is preferable to use a resin material that can be formed into a film and has excellent transparency after curing.
Examples of such materials include polystyrene, polyester, polymethyl methacrylate, vinyl chloride-vinylidene chloride copolymer, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, and polyvinylphenol.

  About each ratio in the case of comprising the photochromic composition in this invention by the photochromic compound / long-chain alkyl compound / polymer represented by General formula (1), a photochromic compound is 0.1 with respect to 100 weight part of polymers. It is desirable that the amount of the long-chain alkyl compound is 10 to 200 parts by weight.

Another feature of the present invention is that an image display medium is formed by forming the photochromic composition as a display layer on a support substrate.
Materials for the supporting substrate include polyethylene terephthalate, polyethersulfone, polycarbonate, phenoxy resin, aromatic polyester, phenolic resin, epoxy resin, etc., or opaque materials formed by adding a white pigment thereto, and paper Materials can be used.
The shape of the support substrate is not limited to a sheet shape, a card shape, or a film shape, and may be a block shape, for example, and the shape is not limited.

Examples of the method for forming the display layer include a vapor deposition method in addition to the coating method, but the coating method is simple, and the photochromic compound, the long-chain structure compound, and the polymer material are both dissolved in a solvent, a printing method, The film may be applied by a method such as spin coating and dried to form a film.
The display layer does not necessarily have to be formed on the entire support substrate, and may be formed on a part.
The preferred thickness of the display layer varies depending on the concentration of the photochromic compound contained in the photochromic composition, but is preferably about 0.1 to 10 μm.

  Another feature of the present invention is that the display layer includes a first display layer containing a photochromic compound represented by the general formula (1) in which the hue in the associated state is yellow and a long-chain alkyl compound, and the hue in the associated state. , A second display layer containing a photochromic compound represented by the general formula (1) and magenta and a long-chain alkyl compound, and a photochromic compound and a long-chain alkyl represented by the general formula (1) where the hue of the associated state is cyan The third display layer containing the compound has a laminated structure.

An intermediate layer may be provided between each layer. In the process of laminating each layer, depending on the method of forming the laminated film, the components of each layer may be mixed around the boundary of each layer, so providing an intermediate layer prevents such mixing and results. As a result, the display layer can be formed in a state in which the association formation change in each layer is appropriately maintained.
The material for forming the intermediate layer is transparent or has a certain degree of resistance to the organic solvent used in the coating method suitably used for forming the display layer, even if it is colored or small. Are preferable, and silicone resin, PVA (polyvinyl alcohol), and the like can be given. The forming method is the same as that of the display layer, and any method may be used, but the coating method is simple.

Next, a description will be given of the image display medium and an apparatus for forming and erasing an image of the image display medium and a recording medium on which a printing surface is formed on a label recording surface of a sheet-like printed material or an optical disk. In that case, first, a method of forming and erasing an image will be described (method of forming a monochrome image).
A step of partially irradiating the image display medium (whether one or more photochromic compounds contained in the display layer) with ultraviolet light according to image data and a step of raising the temperature to a predetermined temperature required for the association As a result, a monochrome image can be formed.
Further, the image can be erased by performing a process of raising the temperature to a predetermined temperature necessary for erasure.

First, a monochrome image is created by partially irradiating UV light based on the data corresponding to the image to be formed, with all the photochromic compounds contained in the display layer decolored as the initial state. Is formed.
Next, by raising the temperature of the display layer to a temperature of about 40 ° C., for example, the photochromic compound contained in the display layer forms an association state, and the monochrome image is stabilized, and is exposed to light such as illumination for a long time. The image will not fade or disappear after exposure.
When the image is to be erased, the display layer is heated to a temperature of, for example, about 100 ° C., so that the association state of the photochromic compound contained in the display layer is solved and the color is erased to erase the image.

  As a method of partially irradiating ultraviolet light, a method of combining a lamp-shaped UV light source and an array-type or surface-type shutter, a method using a UV array light source capable of controlling irradiation ON / OFF by itself, or a UV laser Scan etc. are mentioned.

As a means for raising the temperature to a predetermined temperature required for the meeting, conventional heaters such as a heat roller, a thermal head, a halogen heater, a ceramic heater, and a quartz tube heater can be used. In addition, the heating temperature and heating time of the photosensitive layer of the image display medium can be adjusted according to conditions such as the proximity distance to the image display medium and time, or the contact pressure and time.
Therefore, they can also be used as means for raising the temperature to a predetermined temperature necessary for erasing.

(Method for forming a multicolor image)
A process of developing all the photochromic compounds contained in the display layer by irradiating the image display medium with ultraviolet light, and an image of visible light in a wavelength range corresponding to the maximum absorption wavelength of each of the colored photochromic compounds. By applying a process of selectively erasing the photochromic compound by irradiation based on the data and a process of raising the temperature to a predetermined temperature necessary for the association, the photochromic compound contained in the display layer is applied to one type of image display medium. As a result, a monochrome image is formed, and a multicolor image can be formed on an image display medium having two or more photochromic compounds contained in the display layer.

First, all the photochromic compounds contained in the display layer are colored by irradiating the entire surface of the display layer with ultraviolet light.
Next, the photochromic compound is selectively erased by partially irradiating visible light in the wavelength range corresponding to the maximum absorption wavelength of each colored photochromic compound corresponding to the image to be formed. As a result, a desired image is formed.
Next, by raising the temperature of the display layer to a temperature of about 40 ° C., for example, the photochromic compound contained in the display layer forms an associated state, and the image is stabilized and exposed to light such as illumination for a long time. The image will not fade or disappear.
When this image is to be erased, by raising the temperature of the display layer to a temperature of about 80 ° C., for example, the association state of the photochromic compound contained in the display layer is solved and the color is erased and the image is erased.

As a method of irradiating the entire surface of the display layer with ultraviolet light, a mercury lamp or a xenon lamp may be combined with an optical filter to extract ultraviolet light in a desired wavelength range, or in a specific wavelength range such as an LED or LD. A light-emitting element that emits light may be used.
As a method of partially irradiating visible light, lamps having a configuration in which an optical filter is combined with a white light source may be used, or a light emitting element that emits light in a specific wavelength range such as an LED or LD may be used. Good.
As a method of irradiating only a desired region, for example, a light source array is formed by relatively moving a light source array in which light emitting surfaces capable of controlling ON / OFF of irradiation for each minute region are continuously arranged, and an image display medium. It is also possible by controlling the ON / OFF of the irradiation of each light emitting surface of the array.
As a means for raising the temperature to a predetermined temperature required for the meeting, conventional heaters such as a heat roller, a thermal head, a halon heater, a ceramic heater, and a quartz tube heater can be used. In addition, the heating temperature and heating time of the photosensitive layer of the image display medium can be adjusted according to conditions such as the proximity distance to the image display medium and time, or the contact pressure and time. Therefore, they can also be used as means for raising the temperature to a predetermined temperature necessary for erasing.

  Another feature of the present invention is that the image display medium is partially irradiated with ultraviolet light corresponding to image data, and the display layer is heated to a predetermined temperature required for image stabilization. It is to construct an apparatus equipped with heating means.

The support substrate used for the image display medium in the present invention is not limited to a sheet shape, but may be any shape. Here, taking a sheet-like image display medium as an example, a configuration example and operation of an apparatus capable of forming and erasing a monochrome image This will be described with reference to FIG.
FIG. 3 is a schematic diagram illustrating an example of an image forming apparatus that forms a monochrome image on a sheet-like image display medium according to the first embodiment of the image forming apparatus of the present invention.

  A sheet-like image display medium (1) according to the present invention is set on a sheet mounting table (30) of an image forming apparatus (20). The image display medium (1) is provided with a display layer containing the photochromic compound according to the present invention on a support substrate (10). The color of the support substrate (10) is white, and the image display medium (1) is white when the photochromic compound is not colored.

  The image display medium (1) is conveyed from the insertion port (21) into the image forming apparatus (20) by the conveying roller (22). The ultraviolet light irradiating means (24) forms a monochrome image by partially irradiating ultraviolet light corresponding to the image to be formed to cause color development. This ultraviolet light irradiation means (24) is a method of combining a lamp-shaped UV light source and an array-type or surface-type shutter, a method using a UV array light source capable of controlling ON / OFF of irradiation by itself, a UV laser scan, etc. Consists of.

The image display medium (1) on which the monochrome image is formed on the display layer by the ultraviolet light irradiation means (24) is further fed by the transport roller (22), and the predetermined temperature required for the association by the heating means (25). The temperature is increased to stabilize the image.
As a means for raising the temperature to a predetermined temperature necessary for the meeting, a heat roller, a thermal head, a halogen heater, a ceramic heater, a quartz tube heater, or the like is used.

The image display medium (1) for which the image stabilization processing has been completed by the heating means (25) is conveyed by the conveying roller (23), discharged from the discharge port (29), and placed on the discharge tray (27). Discharged.
For example, it is possible to form a monochrome image by manufacturing the apparatus with such a configuration.

  Next, an optical disk comprising: an ultraviolet light irradiation means for partially irradiating the optical disk label recording surface on which the display layer is formed; and a heating means for raising the temperature to a predetermined temperature necessary for image stabilization. An apparatus for forming an image on the label recording surface will be described.

In recent years, optical discs such as CDs and DVDs have become widespread as information recording media.
Examples of the CD include a reproduction-only CD-ROM, a recordable CD-R, a rewritable CD-RW, and the like. As the DVD, a reproduction-only DVD-ROM, a recordable DVD-R, and a rewritable DVD. -RAM, DVD-RW, etc. For example, a recordable optical disc has an information recording layer.
An optical disk having a label recording surface capable of recording characters and images by handwriting on a label recording surface opposite to the surface on the information recording layer is widely used.

Once a character or image is recorded on the label recording surface by an ink jet printer or handwriting, the image or the like cannot be erased.
In a rewritable optical disk, it is desirable that the label recording surface be rewritten correspondingly when the contents are rewritten.
Therefore, if a recording layer made of the image display medium according to the present invention is provided on the label recording surface, image formation and erasure can be easily performed.
Therefore, the present invention comprises an ultraviolet light irradiation means for partially irradiating the optical disk label recording surface with ultraviolet light, and a heating means for raising the temperature to a predetermined temperature necessary for image stabilization. It is an object of the present invention to provide an apparatus capable of forming an image and erasing it if necessary.

A configuration example of an apparatus for forming an image on an optical disk label recording surface and an outline of the operation will be described with reference to FIG.
FIG. 4 is a schematic diagram showing an apparatus for forming an image on an optical disc label recording surface, showing a second embodiment of the image forming apparatus of the present invention. A configuration example of an apparatus for forming an image on an optical disk label recording surface and an outline of the operation will be described with reference to FIG.
For example, an optical disk (100) is fixed and an apparatus capable of controlling rotation is used as a base, such as an existing optical disk drive apparatus. An optical disc label recording surface (100a) is provided on the surface opposite to the information recording surface of the optical disc (100). The optical disc label recording surface (100a) is provided with the image recording medium according to the present invention. In this case, the substrate of the optical disk constitutes the support base (10).
Then, a heating means (110) and an ultraviolet light irradiation means (111) are provided facing the optical disc label recording surface (100a).

  To record an image, first, the optical disk (100) is rotated in the direction of the arrow in the figure, and the ultraviolet light irradiating means (111) generates a color by partially irradiating ultraviolet light corresponding to the image to be formed. Form an image. Next, the heating means (110) raises the temperature to a predetermined temperature required for the meeting and stabilizes the image, whereby a monochrome image can be formed.

  The formation of an image on the optical disc label recording surface (100a) is basically performed as described above. In practice, however, the rotational speed of the optical disc, the irradiation timing of ultraviolet light corresponding to the radial direction of the disc, and the like. It is necessary to control according to the image data.

Next, a configuration example of an apparatus in which the image recording apparatus of the present invention is provided in the optical disc drive apparatus will be described with reference to the block diagram of FIG.
An image recording apparatus capable of forming an image on the label recording surface without resetting the optical disc is provided for the optical disc (100) provided with the image recording medium of the present invention on the optical disc label recording surface (100a). An optical disc device is provided.

FIG. 5 is a block diagram showing a configuration of an optical disc apparatus provided with an image recording apparatus according to the second embodiment of the present invention.
In FIG. 5, (120) is a drive mechanism part, (123) is a spindle motor, (124) is an optical pickup, (127) is a feed part, (111) is an ultraviolet light irradiation means, (125) is a heating means, (128) is a first analog processing unit, (129) is a servo processing unit, (130) is a first motor driving unit, (131) is a controller, (132) is a laser driving unit, and (133) is a digital signal processing unit. , (134) is a buffer memory, (137) is an irradiation means driving unit, and (100) is an optical disk.

The operation of the optical disc apparatus configured as described above according to an embodiment of the present invention will be described.
In FIG. 5, the drive mechanism (120) includes a spindle motor (123) that rotates the optical disc (100), and an optical pickup (124) that records or reproduces information on the information recording surface of the optical disc (100). The optical disk label recording surface (100a) is irradiated with ultraviolet rays to form a visible image, and an optical pickup (124) is mounted on a carriage mounted with an optical pickup (124) in the radial direction of the optical disc (100). And a heating unit (125) for stabilizing the image by raising the temperature to a predetermined temperature required for the meeting.

  The first analog signal processing unit (128) generates a focus error signal based on a signal output from an optical sensor (not shown) in the optical pickup (124) provided in the drive mechanism unit (120). A tracking error signal is generated and output to the servo processing unit (129).

The servo processing unit (129) generates a lens position signal indicating the relative positional relationship between the objective lens of the optical pickup (124) and the carriage, and outputs the lens position signal to the first motor driving unit (130). The first motor drive unit (130) drives the optical pickup (124), the spindle motor (123), and the feed unit (127).
The servo processing unit (129) includes an ON / OFF circuit, an arithmetic circuit, a filter circuit, an amplifier circuit, and the like, and the objective of the optical pickup (124) is set so that the light beam spot follows the information track of the optical disc (100). Focus / tracking control of the lens is performed, and further, feed control is performed using the low-frequency component of the tracking error signal so that the objective lens maintains a substantially neutral position.

  The feed unit (127) is composed of a feed motor, a gear, a screw shaft (not shown), and the like, and the carriage moves in the radial direction of the optical disc (100) by rotating the feed motor.

  The digital signal processing unit (133) converts the analog signal sent from the first analog signal processing unit (128) into a digital signal, and the controller (131), the laser driving unit (132), and the irradiation means driving unit (137). ), And sent to each part of the buffer memory (134).

  The controller (131) performs overall control of the servo unit configured as described above, and includes a first analog signal processing unit (128), a servo processing unit (129), a first motor driving unit (130), The digital signal processing unit (133) and the irradiation unit driving unit (137) receive signals sent from the respective units of the irradiation unit driving unit, perform arithmetic processing of these signals, and the result (signal) of the arithmetic processing is transmitted to each unit. , And driving and processing are executed in each part to control each part.

  The first motor drive unit (130) uses the counter electromotive current obtained from the spindle motor (123) to generate an FG pulse signal having a frequency corresponding to the rotational speed of the spindle motor (123) in the digital signal processing unit (133). Is output to the PLL circuit.

  The PLL circuit multiplies the FG pulse signal and generates a PLL clock signal used for visible image formation. For example, when the spindle motor (123) generates n FG pulses while the optical disk rotates once, that is, when the optical disk rotates once, the PLL circuit generates a PLL clock signal obtained by multiplying the FG pulse.

  The digital signal processing unit (133) reads out data necessary for image formation indicating the gradation degree of one coordinate from the buffer memory (134) for each PLL clock signal, that is, every time the optical disk rotates by a certain angle. A lighting control signal is sent to the irradiation means driving unit (137).

The ultraviolet light irradiation means (111) in this embodiment has a plurality of irradiation portions in a line shape in the radial direction of the optical disc (100).
As the line-shaped ultraviolet light irradiation means (111), a combination of a lamp-shaped UV light source and an array-type shutter, or a UV array light source capable of controlling irradiation ON / OFF by itself is used. In the case of using a shutter, the irradiation means driving unit (137) controls the opening and closing of the shutter corresponding to the image data. Further, when the UV array light source is used, the irradiation means driving unit (137) controls ON / OFF.

By the way, as shown in the conceptual diagram of the recording track on the label recording surface in FIG. 6, the number of dots to be recorded on the optical disc (100) increases along the outer peripheral direction. When the line-shaped ultraviolet light irradiation means (126) is used, the number of dots to be recorded is different between the inner peripheral side and the outer peripheral side. For this reason, the light emission part corresponding to the dot of the ultraviolet light irradiation means (126) of the inner peripheral side has fewer dots to be lit than the light emission part of the outer peripheral side.
According to the example of FIG. 6, first, the dots corresponding to the L3 and L2 lines are turned on. At this time, the L1 line is not lit. Subsequently, when the optical disk (100) for one dot in the L3 line is rotated, the dots corresponding to the L3 line are turned on. At this time, the L1 and L2 lines are not lit. Subsequently, when the optical disk (100) for one dot of three lines is rotated, the dots corresponding to the L1, L2, and L3 lines are turned on. Further, when the optical disk (100) for one dot in the L3 line is rotated, the dots corresponding to the L2 and L3 lines are turned on. At this time, the L1 line is not lit.
Thus, in this example, while the L3 line 4 dots are lit, the L2 line is controlled to be 3 dots and the L1 line is 1 dot, and the number of dots recorded on the inner and outer peripheral sides is different. Controlled to record.

Next, an image recording operation on the label recording surface of the optical disc (100) will be described.
When the optical disc (100) is inserted, the optical disc apparatus rotates the spindle motor (123), starts the activation process, applies focus servo and tracking servo, and disc discriminates.
Next, a visible image recording operation is performed on the optical disc label recording surface (100a) according to a user instruction. In the image recording operation on the optical disk label recording surface (100a), the disk rotation speed is first set.

For setting the rotation speed of the optical disc (100), various user input information is transmitted from the host device to the controller (131) via the digital signal processing unit (133), and the controller (131) is based on the information. An instruction is issued to the first motor drive unit (130) via the servo processing unit (129) to operate the spindle motor (123).
Further, the controller (131) transmits information to the ultraviolet light irradiation means (111) via the irradiation means driving unit (137), and starts the lighting control operation of the ultraviolet light irradiation means (111).

  Next, the controller (131) detects each recording position linear velocity from the operation status of the spindle motor (123). The recording position linear velocity detection is calculated from the radial position of each irradiation section of the ultraviolet light irradiation means (126) and the rotation speed of the spindle motor (123).

  Subsequently, an image recording operation on the label recording surface (100a) of the optical disc (100) is started. In the image recording operation on the label recording surface (100a) of the optical disc (100), the controller (131) first gives an instruction to the digital signal processing unit (133) based on the information already received from the user. This is transmitted in the order of the ultraviolet light irradiation means (111) via the irradiation means driving section (137), and the desired irradiation section of the ultraviolet light irradiation means (111) is turned on.

  By rotating the optical disk 1 once, an image is recorded on the label recording surface (100a) of the optical disk (100). Here, when the output of the recording power of the ultraviolet light irradiating means (111) is limited, the optical disk (100) is rotated several times in order to perform the recording operation a plurality of times at the same location and to perform the overlapping recording. What is necessary is just to comprise so that it may record repeatedly on the same location.

Then, after an image is recorded on the label recording surface (100a) of the optical disc (100), an operation for stabilizing the image is started.
To stabilize the image, the heating means (110) is heated to a predetermined temperature required for the meeting, the spindle motor (123) is driven, the optical disk (100) is rotated, and the heating means (110) is passed under the heating means (110). . When the temperature is raised to a predetermined temperature required for the meeting by passing once, the rotation of the optical disk 1 may be one degree. However, according to the power of the heating means (110), the optical disk (100) is rotated a plurality of times. Rotate and stabilize.

Next, a third embodiment of the present invention will be described.
In the third embodiment, as shown in FIG. 7, an ultraviolet light irradiation means (24) for partially irradiating the image display medium with ultraviolet light, and a display layer at a predetermined temperature necessary for image stabilization. A second heating means (25b) for raising the temperature and a first heating means (25a) for raising the temperature of the display layer to a predetermined temperature necessary for erasing the formed image are provided.

FIG. 7 is a schematic diagram showing an example of an image forming apparatus for forming and erasing a monochrome image on a sheet-like image display medium according to the third embodiment of the present invention.
A sheet-like image display medium (1) according to the present invention is set on a sheet mounting table (30) of an image forming apparatus (20). The image display medium (1) is provided with a display layer containing the photochromic compound according to the present invention on a support substrate (10). The color of the support substrate (10) is white, and the image display medium (1) is white when the photochromic compound is not colored.

  The image display medium (1) is conveyed from the insertion port (21) into the image forming apparatus (20) by the conveying roller (22). If necessary, the first heating means (25a) erases the image by raising the temperature of the display layer to a predetermined temperature necessary for erasing the image. Then, the ultraviolet light irradiation means (24) forms a monochrome image by irradiating the ultraviolet light partially in correspondence with the image to be formed to cause color development.

The image display medium (1) on which the monochrome image is formed on the display layer by the ultraviolet light irradiation means (24) is further fed by the transport roller (22), and necessary for the meeting by the second heating means (25b). The image is stabilized by raising the temperature to a predetermined temperature.
The image display medium (1) for which the image stabilization processing has been completed by the second heating means (25b) is transported by the transport roller (23), discharged from the discharge port (29), and placed on the discharge tray (27). To be discharged.
For example, it is possible to form and erase a monochrome image by manufacturing the apparatus with such a configuration.

  In the above configuration example, the first heating means (25a) for erasing and the second heating means (25b) for stabilizing the image are provided separately, but each of the erasing process and the stabilizing process is performed using only one heating means. It may be used properly by heating it to the temperature required for it. In that case, the image display medium (1) is transferred to the heating means again after the erasing process by the heating means and the image forming process by the ultraviolet light irradiation means (24) while being conveyed, and the stabilization process is performed. However, various configurations are conceivable.

Next, a fourth embodiment of the present invention will be described.
In this embodiment, as shown in FIG. 8, the optical disk label recording surface (100a) on which the display layer is formed is irradiated with ultraviolet light irradiation means (111) that partially irradiates ultraviolet light, and image stabilization. An apparatus comprising second heating means (125b) for raising the display layer to a required predetermined temperature and first heating means (125a) for raising the display layer to a predetermined temperature necessary for erasing the formed image Is to build.

An example of the configuration of the apparatus is the same as that shown in FIGS.
4 and 5, the second heating means (125b) for raising the display layer to a predetermined temperature necessary for image stabilization, and the display layer at a predetermined temperature necessary for erasing the formed image. A first heating means (125a) for raising the temperature of

  Note that the same configuration as that shown in FIGS. 4 and 5 may be used by heating the same heating means to respective temperatures required for the erasing step and the stabilizing step. In this case, for example, if necessary, the display layer is first heated to a predetermined temperature necessary for erasing the image, and the rotation of the disk is controlled to erase the image. Next, a monochrome image is formed by irradiating the ultraviolet light partially with the ultraviolet light irradiation means in correspondence with the image to be formed to cause color development. Next, the temperature is raised to a predetermined temperature required for the association by the heating means and the image is stabilized, whereby a monochrome image can be formed and erased.

Next, a fifth embodiment of the present invention will be described.
In this embodiment, as shown in FIG. 9, the image display medium (1) is irradiated with ultraviolet light irradiation means (24) for irradiating the display layer with ultraviolet light, and the maximum absorption wavelength of each photochromic compound in the colored state. And a visible light irradiating means (26) for irradiating visible light in a wavelength region corresponding to the above, and a heating means (25) for raising the temperature of the display layer to a predetermined temperature necessary for image stabilization.

The configuration example and operation of the fifth embodiment will be described with reference to FIG.
A sheet-like image display medium (1) according to the present invention is set on a sheet mounting table (30) of an image forming apparatus (20). The image display medium (1) is provided with a display layer containing the photochromic compound according to the present invention on a support substrate (10). The color of the support substrate (10) is white, and the image display medium (1) is white when the photochromic compound is not colored.

The image display medium (1) is conveyed from the insertion port (21) into the image forming apparatus (20) by the conveying roller (22). If necessary, the temperature of the display layer is raised to a predetermined temperature necessary for erasing the image by the heating means (25) to erase the image. Then, all photochromic compounds contained in the display layer are colored by the ultraviolet light irradiation means (24).
The colored image display medium (1) is sent to the visible light irradiation means (26) by the transport roller (22). The visible light irradiation means (26) partially irradiates visible light in a wavelength region corresponding to the maximum absorption wavelength of each colored photochromic compound corresponding to the image to be formed, as shown in FIG. Selectively decolorize photochromic compounds. By selectively erasing, a desired image is formed.

Next, the heating means (25) raises the display layer to a predetermined temperature necessary for the association to stabilize the image, and the image is discharged from the discharge port (29) to the outside of the apparatus. For example, it is possible to form a monochrome image or a multicolor image by manufacturing the apparatus with such a configuration.
Next, a sixth embodiment of the present invention will be described. In this embodiment, as shown in FIG. 10, the optical disc label recording surface (100a) on which the display layer is formed is irradiated with ultraviolet light irradiation means (111) for irradiating the display layer with ultraviolet light, A visible light irradiating means (126) for irradiating visible light in a wavelength region corresponding to the maximum absorption wavelength of the photochromic compound, and a heating means (110) for raising the display layer to a predetermined temperature necessary for image stabilization. Is done.

A configuration example and operation of the apparatus according to the sixth embodiment will be described with reference to FIG.
For example, an optical disk (100) is fixed and an apparatus capable of controlling rotation is used as a base, such as an existing optical disk drive apparatus. An optical disc label recording surface (100a) is provided on the surface opposite to the information recording surface of the optical disc (100). The optical disc label recording surface (100a) is provided with the image recording medium according to the present invention. The image recording medium (1) is configured to be capable of color display. As shown in FIG. 1, the image display medium (1) is configured in the same manner as having the first, second, and third photosensitive layers (11), (12), and (13).
The first photosensitive layer (11) includes a fulgide compound having a maximum absorption wavelength in the range of 400 nm to less than 500 nm, and the second photosensitive layer (12) has a maximum absorption wavelength of 500 nm to less than 600 nm. The layer containing the fulgide compound in the range and the third photosensitive layer (13) are composed of a layer containing the fulgide compound in which the maximum absorption wavelength is in the range of 400 nm to less than 500 nm. The photosensitive layer thus formed is colorless, and the color of the support substrate (10) is white. This image display medium (1) is recognized as white by the observer.

Then, a heating means (110), an ultraviolet light irradiation means (111), and a visible light irradiation means (126) are provided facing the optical disc label recording surface (100a). The visible light irradiation means (126) is configured to emit three types of visible light corresponding to the respective maximum absorption wavelengths in order to perform color display. For example, it is composed of three types of light emitting diode arrays.
For example, the first light emitting diode array is irradiated with visible light having a center wavelength of 460 nm and a half width of 10 nm, and the second light emitting diode array is irradiated with visible light having a center wavelength of 560 nm and a half width of 10 nm. As such, it may be configured such that visible light having a center wavelength of 660 nm and a half width of 10 nm can be irradiated. By irradiating the three types of light emitting diode arrays based on the corresponding image data, the display layer having an absorption wavelength in the irradiated visible light is selectively decolored and a color image is displayed.

First, when the optical disk (100) is rotated in the direction of the arrow in the figure and the ultraviolet light irradiating means (111) partially irradiates ultraviolet light corresponding to the image to be formed to cause color development, all three display layers are formed. Color develops to black.
Next, the visible light irradiation means (126) selectively irradiates the photochromic compound by partially irradiating visible light in a wavelength region corresponding to the maximum absorption wavelength of each photochromic compound colored corresponding to the image to be formed. A desired image is formed by decoloring.
Thereafter, the heating means (110) raises the temperature to a predetermined temperature required for the meeting and stabilizes the image, whereby a monochrome image or a multicolor image can be formed.

Next, a sixth embodiment in which the above apparatus is applied to an optical disk drive apparatus will be described with reference to the block diagram of FIG.
Although the basic configuration is the same as that shown in FIG. 5, the image shown in FIG. 5 was recorded by the irradiation of the ultraviolet light irradiation means (111). Image recording based on the image data is performed by the light irradiation means (126).
The same components as those in FIG. 5 are denoted by the same reference numerals, and the description thereof is omitted here in order to avoid duplication of description.

FIG. 11 is a block diagram showing a configuration of an optical disc apparatus provided with an image recording apparatus according to the sixth embodiment of the present invention.
In FIG. 11, (120) is a drive mechanism unit, (123) is a spindle motor, (124) is an optical pickup, (127) is a feed unit, (111a) is an ultraviolet light irradiation means, and (126) is a visible light irradiation. Means, (125) is a heating means, (128) is a first analog processing section, (129) is a servo processing section, (130) is a first motor driving section, (131) is a controller, and (132) is laser driven. , (133) is a digital signal processing unit, (134) is a buffer memory, (137a) is a visible light driving unit, and (100) is an optical disk.

In the embodiment shown in FIG. 5, image data is recorded by the ultraviolet light irradiation means. For this reason, it is configured to be able to be turned on / off corresponding to the pixel dot. On the other hand, in the embodiment shown in FIG. 11, the ultraviolet light irradiation means (111a) may color the entire image display medium (1) regardless of the pixel dots. For this reason, what is necessary is just to be able to irradiate the radial direction of the optical disc (100) in a line shape with a mercury lamp or the like.
In this embodiment, the light irradiation based on the image data is performed by the visible light irradiation means (126). Therefore, as described above, the visible light irradiation means (126) is configured to be able to irradiate three types of visible light corresponding to the respective maximum absorption wavelengths in order to perform color display.
In this embodiment, the first light-emitting diode array can emit visible light with a center wavelength of 460 nm and a half-value width of 10 nm, and the second light-emitting diode array emits visible light with a center wavelength of 560 nm and a half-value width of 10 nm. As a light-emitting diode array, a light-emitting diode array capable of irradiating visible light with a center wavelength of 660 nm and a half-value width of 10 nm is prepared, and the three light-emitting diode arrays constitute the visible light irradiation means (126). The visible light irradiating means (126) performs lighting control of each dot of the light emitting diode array corresponding to the image data by a driving signal given from the visible light driving unit (137a).

Next, an image recording operation on the label recording surface of the optical disc (100) will be described.
When the optical disc (100) is inserted, the optical disc apparatus rotates the spindle motor (123), starts the activation process, applies focus servo and tracking servo, and disc discriminates.
Next, a visible image recording operation is performed on the optical disc label recording surface (100a) according to a user instruction. In the image recording operation on the optical disk label recording surface (100a), the disk rotation speed is first set.

For setting the rotation speed of the optical disc (100), various user input information is transmitted from the host device to the controller (131) via the digital signal processing unit (133), and the controller (131) is based on the information. An instruction is issued to the first motor drive unit (130) via the servo processing unit (129) to operate the spindle motor (123).
The controller (131) transmits information to the ultraviolet light irradiation means (111a) and the visible light irradiation means (126) via the irradiation means driving unit (137), and the ultraviolet light irradiation means (111a) and the visible light irradiation. The lighting control operation of the means (126) is started.

  Next, the controller (131) detects each recording position linear velocity from the operation status of the spindle motor (123). The recording position linear velocity detection is calculated from the radial position of each irradiation section of the visible light irradiation means (126) and the rotation speed of the spindle motor (123).

Subsequently, an image recording operation on the label recording surface (100a) of the optical disc (100) is started. In the image recording operation on the label recording surface (100a) of the optical disc (100), first, the ultraviolet ray irradiation means (111a) irradiates the optical disc label recording surface (100a) with ultraviolet rays.
All three display layers are colored and become black by the ultraviolet irradiation. When the ultraviolet light irradiation means (111a) detects that the optical disk (100) has rotated once in the ultraviolet light irradiation means (111a), the irradiation stops. By controlling in this way, it is possible to prevent the color erased by the visible light irradiation means (126) from recurring.

  Based on the information already received from the user, the controller (131) first issues an instruction to the digital signal processing unit (133), which passes through the visible light driving unit (137a), and the visible light irradiation means ( 126), and a desired light emitting diode of the visible light irradiation means (126) is turned on, whereby the display layer having an absorption wavelength in the irradiated visible light is selectively decolored, and a color image or a monochrome image is formed. Is displayed.

  By rotating the optical disk (1) once, an image is recorded on the label recording surface (100a) of the optical disk (100). Here, when the output of the recording power of the visible light irradiating means (126) is limited, the optical disk (100) is rotated several times in order to perform the overlapping recording in which the recording operation is performed a plurality of times at the same location. What is necessary is just to comprise so that it may superimpose and record in a location.

Then, after an image is recorded on the label recording surface (100a) of the optical disc (100), an operation for stabilizing the image is started.
To stabilize the image, the heating means (110) is heated to a predetermined temperature required for the meeting, the spindle motor (123) is driven, the optical disk (100) is rotated, and the heating means (110) is passed under the heating means (110). .
When the temperature is raised to a predetermined temperature required for the meeting by passing once, the rotation of the optical disk (1) may be one degree. However, according to the power of the heating means (110), the optical disk (100 ) Is rotated and stabilized.
The heating means (110) uses a ceramic heater, and the temperature of the display layer of the image display medium is controlled by the conveyance speed of the image display medium so that the temperature can be raised to 100 ° C. and 50 ° C., respectively. .

  Next, as shown in FIG. 12, in the seventh embodiment of the present invention, an ultraviolet light irradiation means (24) for irradiating the display layer with ultraviolet light on the image display medium, and each photochromic in the colored state. Visible light irradiation means (26) for irradiating visible light in a wavelength range corresponding to the maximum absorption wavelength of the compound, first heating means (25b) for raising the display layer to a predetermined temperature necessary for image stabilization, and formed And a second heating means (25a) for raising the temperature of the display layer to a predetermined temperature necessary for erasing the image.

FIG. 12 is a schematic diagram illustrating an example of an image forming apparatus that forms a multicolor image or a monochrome image and deletes it on a sheet-like image display medium according to a seventh embodiment of the present invention.
A sheet-like image display medium (1) according to the present invention is set on a sheet mounting table (30) of an image forming apparatus (20). The image display medium (1) is provided by laminating three display layers containing the photochromic compound according to the present invention on a support substrate (10). The color of the support substrate (10) is white, and the image display medium (1) is white when the photochromic compound is not colored.

  The image display medium (1) is conveyed from the insertion port (21) into the image forming apparatus (20) by the conveying roller (22). If necessary, the first heating means (25a) erases the image by raising the temperature of the display layer to a predetermined temperature necessary for erasing the image. Then, the ultraviolet light irradiating means (24) irradiates the ultraviolet light so that all the photochromic compounds contained in the display layer are colored.

The visible light irradiation means (26) partially irradiates visible light in a wavelength region corresponding to the maximum absorption wavelength of each colored photochromic compound to selectively erase the photochromic compound, thereby obtaining a desired image. Form.
The image display medium (1) with the image formed on the display layer is further fed by the conveying roller (22), and the second heating means (25b) raises the temperature to a predetermined temperature required for the meeting, thereby stabilizing the image. It becomes.

The image display medium (1) for which the image stabilization processing has been completed by the second heating means (25b) is conveyed by the conveying roller (23), discharged from the discharge port (29), and discharged from the discharge tray (27). Discharged to the top.
For example, it is possible to form and erase a color image or a monochrome image by manufacturing the device with such a configuration.

  In the above configuration example, the first heating means (25a) for erasing and the second heating means (25b) for stabilizing the image are provided separately, but each of the erasing process and the stabilizing process is performed using only one heating means. It may be used properly by heating it to the temperature required for it. In that case, the image display medium (1) is transferred to the heating means again after the erasing process by the heating means and the image forming process by the ultraviolet light irradiation means (24) while being conveyed, and the stabilization process is performed. However, various configurations are conceivable.

Next, an eighth embodiment of the present invention will be described.
In this embodiment, as shown in FIG. 13, an ultraviolet light irradiation means (111) for irradiating the display layer with ultraviolet light on the optical disc label recording surface (100a) on which the display layer is formed, Visible light irradiating means (126) for irradiating visible light in a wavelength region corresponding to the maximum absorption wavelength of the photochromic compound, and second heating means (125b) for raising the display layer to a predetermined temperature necessary for image stabilization, And constructing an apparatus including first heating means (125a) for raising the temperature of the display layer to a predetermined temperature necessary for erasing the formed image.

An example of the configuration of the apparatus is the same as that shown in FIGS.
10 and 11, the second heating means (125b) for raising the display layer to a predetermined temperature necessary for image stabilization, and the display layer at a predetermined temperature necessary for erasing the formed image. A first heating means (125a) for raising the temperature of

As an example of the configuration of the apparatus, the same configuration as that shown in FIG. 12 may be used so that the same heating means is heated to the respective temperatures required for the erasing step and the stabilizing step. In this case, for example, if necessary, the display layer is first heated to a predetermined temperature necessary for erasing the image, and the rotation of the optical disc (100) is controlled to erase the image.
Next, all the photochromic compounds contained in the display layer are colored by the ultraviolet light irradiation means (111), and then each photochromic compound colored by the visible light irradiation means (126) corresponding to the image to be formed. A desired image is formed by partially irradiating the photochromic compound by partially irradiating visible light in a wavelength region corresponding to the maximum absorption wavelength.
Next, it is possible to form a monochrome image or a multi-color image by stabilizing the image by raising the temperature to a predetermined temperature required for the association by the heating means.
About a heating means, as shown in FIG. 13, it is good also as a structure which provides the heating means for exclusive use for an erasing process and a stabilization process one by one.

Hereinafter, the present invention will be specifically described based on examples.
Example 1
As a photochromic compound, 8′-cyano-1,3-dihydro-3,3-dimethyl-5-methoxy-1-octadecyl-5′-docosanoyloxymethylspiro [2H-indole-2,3 ′-[3H] naphtho [ 2,1-b] [1,4] oxazine] (hereinafter referred to as “PC1”), n-eicosane was used as the long-chain alkyl compound, and polymethyl methacrylate was used as the binder.
20 parts by weight of n-docosane was added to 20 parts by weight of PC1, and 80 parts by weight of polymethyl methacrylate was added. Using toluene as a solvent, a coating solution was prepared to produce a cast film on a quartz substrate.

When the absorption spectrum before light irradiation was measured, the absorption band was recognized in the range of 300-400 nm, and it was colorless.
When this was irradiated with 366 nm ultraviolet light extracted from a high-pressure mercury lamp, it developed blue and the maximum absorption wavelength of the absorption spectrum was 605 nm. When this was heat-treated at 40 ° C. with a heat roller, the hue changed to cyan, and the maximum absorption wavelength of the absorption spectrum was 628 nm.
When this was again heat-treated again at 80 ° C. with a heat roller, it returned to colorless and no absorption was observed in the visible region.

  A cast film having the same formulation as described above was formed on a white PET (polyethylene terephthalate) substrate (thickness: 188 μm), and a PVA film (thickness: 2 μm) was further formed as a protective layer to produce an image display medium. Since the display layer formed in this way is colorless and the color of the substrate is white, the produced image display medium was recognized as white by the observer.

Next, after irradiating the display layer of the image display medium with 366 nm ultraviolet light again to saturate the color reaction, the heat treatment is performed at 40 ° C. with a heat roller, and then visible light having a center wavelength of 630 nm and a half width of 10 nm is emitted. Irradiation was performed at an illuminance of 1 mW / cm ² for 1000 hours, but the display layer did not change and was not decolored. That is, it was confirmed that the association state was stably maintained even when irradiated with visible light for a long time. Thereafter, when the heat treatment was temporarily performed at 80 ° C. by the heat roller, the display layer returned to colorless.
In addition, the image display medium was irradiated with 366 nm ultraviolet light to develop a color, heat treated at 40 ° C. with a heat roller to associate with it, and then decolored with an 80 ° C. heat roller 100 times. It did not occur at all, and good repeated durability was confirmed.

(Examples 2 to 10, Comparative Examples 1 to 13)
A cast film was prepared on white PET in the same procedure as in Example 1, using a compound in which the carbon number of the long chain structure site of R ₁ and R ₂ of the photochromic compound used in Example 1 was as shown in Table 1. .
After irradiating these cast films with ultraviolet light, heat treatment was performed at 40 ° C. with a heat roller, and a fluorescent lamp was irradiated with an illuminance of 700 lx for 1000 hours. The state of the cast film after 1000 hours is shown in Table 1.

(Example 11)
The image display medium produced in Example 1 was formed using the apparatus shown in FIG. The image display medium (1) is transported from the insertion port (21) into the image forming apparatus (20) by the transport roller (22), and is heated to 80 ° C. by the heat roller (first heating means) (25a). Erase.
Next, when the display layer was irradiated with an ultraviolet light LED (ultraviolet light irradiation means) (24), the display layer was colored blue. Next, heat treatment was performed at 40 ° C. by a heat roller (second heating means) (25b), and the image display medium colored cyan was discharged from the discharge port (29). The image display medium was irradiated with a fluorescent lamp at an illuminance of 700 lx for 90 days, but the display layer did not change and was not erased. That is, it was confirmed that the association state was stably maintained even when irradiated with visible light for a long time. Thereafter, when the heat treatment was temporarily performed at 80 ° C. by the heat roller (25a), the display layer returned to colorless.

Example 12
As a photochromic compound, 5-methoxy-8′-nitro-1-octadecyl-5′-docosanamide spiro [2H-benzo [d] thiazole-2,3 ′-[3H] naphtho [2,1-b] [ 1,4] oxazine] (hereinafter referred to as “PC2”), n-octadecane was used as the long-chain alkyl compound, and polymethyl methacrylate was used as the binder.
20 parts by weight of n-eicosane and 80 parts by weight of polymethyl methacrylate were added to 20 parts by weight of PC2. Using toluene as a solvent, a coating solution was prepared to produce a cast film on a quartz substrate.

When the absorption spectrum before light irradiation was measured, the absorption band was recognized in the range of 300-400 nm, and it was colorless.
When this was irradiated with 366 nm ultraviolet light extracted from a high-pressure mercury lamp, it developed blue and the maximum absorption wavelength of the absorption spectrum was 611 nm. When this was heat-treated at 40 ° C. with a heat roller, the hue changed to cyan, and the maximum absorption wavelength of the absorption spectrum was 631 nm.
When this was again heat-treated again at 80 ° C. with a heat roller, it returned to colorless and no absorption was observed in the visible region.

  Next, a cast film having the same formulation as described above was formed on a white PET (polyethylene terephthalate) substrate (thickness: 188 μm), and a PVA film (thickness: 2 μm) was further formed as a protective layer to produce an image display medium. . Since the display layer formed in this way is colorless and the color of the substrate is white, the produced image display medium was recognized as white by the observer.

Next, after irradiating the display layer of the image display medium with 366 nm ultraviolet light again to saturate the color reaction, the heat treatment is performed at 40 ° C. with a heat roller, and then visible light having a center wavelength of 630 nm and a half width of 10 nm is emitted. Irradiation was performed at an illuminance of 1 mW / cm ² for 1000 hours, but the display layer did not change and was not erased. That is, it was confirmed that the association state was stably maintained even when irradiated with visible light for a long time. Thereafter, when the heat treatment was temporarily performed at 80 ° C. by the heat roller, the display layer returned to colorless.
In addition, the image display medium was irradiated with 366 nm ultraviolet light to develop a color, heat treated at 40 ° C. with a heat roller to associate with it, and then decolored with an 80 ° C. heat roller 100 times. It did not occur at all, and good repeated durability was confirmed.

(Example 13)
A cast film having the same formulation as that of Example 12 was formed on the optical disc (100), and a PVA film (film thickness: 2 μm) was further formed as a protective layer to produce an image display medium. Since the display layer formed in this way is colorless and the color of the substrate is white, the produced image display medium was recognized as white by the observer.
Next, an image was formed on the optical disk (100) using the apparatus shown in FIG. When an ultraviolet LED (ultraviolet light irradiation means) (111) equipped with a liquid crystal shutter was arbitrarily irradiated, the portion irradiated with the ultraviolet light was colored blue. When heat treatment was performed at 40 ° C. by the ceramic heater (second heating means) (125b), the portion that was colored blue exhibited cyan.
The optical disc (100) was irradiated with a fluorescent lamp at an illuminance of 700 lx for 90 days, but the display layer did not change and was not erased. Thereafter, when the heat treatment was temporarily performed at 80 ° C. by the ceramic heater (125a), the display layer returned to colorless.

(Example 14)
As a photochromic compound, 8′-bromo-1,3-dihydro-3,3,5-trimethyl-1-octadecyl-5′-docosasyloxyspiro [2H-indole-2,3 ′-[3H] naphtho [2,1 -B] [1,4] oxazine] (hereinafter referred to as “PC3”), n-eicosane was used as the long-chain alkyl compound, and polystyrene was used as the binder.
20 parts by weight of n-eicosane and 80 parts by weight of polystyrene were added to 20 parts by weight of PC3. A coating solution was prepared using toluene as a solvent to prepare a cast film on a quartz substrate. When the absorption spectrum before light irradiation was measured, the absorption band was recognized in the range of 300 nm-400 nm, and it was colorless.

When this was irradiated with 366 nm ultraviolet light extracted from a high-pressure mercury lamp, it developed blue-violet and the maximum absorption wavelength of the absorption spectrum was 574 nm.
When this was heat-treated at 40 ° C. with a heat roller, the hue changed to magenta, and the maximum absorption wavelength of the absorption spectrum was 528 nm. When this was again heat-treated again at 80 ° C. with a heat roller, it returned to colorless and no absorption was observed in the visible region.

20 parts by weight of n-eicosane and 80 parts by weight of polystyrene were added to 20 parts by weight of PC3. A coating solution is prepared using toluene as a solvent, a cast film is formed on a white PET (polyethylene terephthalate) substrate (thickness: 188 μm), and 20 weight parts of n-eicosane is added to 20 parts by weight of PC2. Then, 80 parts by weight of polystyrene was added, and a cast film was formed by a coating solution using toluene as a solvent to prepare an image display medium. Since the display layer formed in this way is colorless and the color of the substrate is white, the produced image display medium was recognized as white by the observer.
When the display layer of this image display medium was irradiated with 366 nm ultraviolet light, both PC2 and PC3 developed color and exhibited a bluish green color. Further, when this was irradiated with white light, the display layer became colorless and transparent again, so that the image display medium was recognized as white.
This image display medium was again irradiated with 366 nm ultraviolet light to develop color, and then a part thereof was irradiated with visible light having a central wavelength of 610 nm and a half-value width of 10 nm. Exhibited a bluish purple color. Moreover, when another part was irradiated with visible light having a center wavelength of 570 nm and a half-value width of 10 nm, PC3 was selectively decolored and the irradiated part exhibited blue. Further, when this was irradiated with white light, the display layer became colorless and transparent again, so that the image display medium was recognized as white.

  This image display medium was again irradiated with 366 nm ultraviolet light to develop a color, and then a part of the image display medium was irradiated with visible light having a center wavelength of 610 nm and a half-value width of 10 nm. Exhibited a bluish purple color. Further, when another portion was irradiated with visible light having a center wavelength of 570 nm and a half-value width of 10 nm, PC3 was selectively decolored and the irradiated portion exhibited blue. After that, when the heat treatment was carried out to 40 ° C. with a heat roller, the portion showing blue-purple became magenta, and the portion showing blue showed cyan. This image display medium was irradiated with a fluorescent lamp at an illuminance of 700 lx for 1000 hours, but there was no change in the display layer. That is, it was confirmed that the association state was stably maintained even when irradiated with visible light for a long time.

(Example 15)
The image display medium used in Example 14 was formed using the apparatus shown in FIG. The image display medium (1) is transported from the insertion port (21) into the image forming apparatus (20) by the transport roller (22), and is heated to 80 ° C. by the heat roller (first heating means) (25a). Erase.
Next, when the display layer was irradiated with an ultraviolet light LED (ultraviolet light irradiation means) (24), the display layer was colored blue-green.
Next, an arbitrary image was formed by an LED (visible light irradiation means) (26) having a central wavelength of 610 nm and a half-value width of 10 nm and an LED (visible light irradiation means) (26) having a half-value width of 10 nm and a liquid crystal shutter. Subsequently, heat treatment was performed at 40 ° C. by the heat roller (second heating means) (25b), and one image display medium displaying an arbitrary image was discharged from the discharge port (29). The image display medium was irradiated with a fluorescent lamp at an illuminance of 700 lx for 1000 hours, but the display layer did not change and was not decolored. That is, it was confirmed that the association state was stably maintained even when irradiated with visible light for a long time.

(Example 16)
As a photochromic compound, 8′-bromo-5-methoxy-1-octadecyl-5′-docosanate spiro [2H-benzo [d] oxazole-2,3 ′-[3H] naphtho [2,1-b] [1 , 4] oxazine] (hereinafter referred to as “PC4”), n-octadecane was used as the long-chain alkyl compound, and polystyrene was used as the binder.
20 parts by weight of n-docosane was added to 20 parts by weight of PC4, and 80 parts by weight of polystyrene was added. A coating solution was prepared using toluene as a solvent to prepare a cast film on a quartz substrate.
When the absorption spectrum before light irradiation was measured, the absorption band was recognized in the range of 300 nm-400 nm, and it was colorless.

When this was irradiated with 366 nm ultraviolet light extracted from a high-pressure mercury lamp, it was colored red and the maximum absorption wavelength of the absorption spectrum was 493 nm. When this was heat-treated at 40 ° C. with a heat roller, the hue changed to yellow, and the maximum absorption wavelength of the absorption spectrum was 460 nm. When this was again heat-treated again at 80 ° C. with a heat roller, it returned to colorless and no absorption was observed in the visible region.
In addition, the image display medium was irradiated with 366 nm ultraviolet light to develop a color, heat treated at 40 ° C. with a heat roller to associate with it, and then decolored with an 80 ° C. heat roller 100 times. It did not occur at all, and good repeated durability was confirmed.

20 parts by weight of n-octadecane and 80 parts by weight of polystyrene were added to 20 parts by weight of PC4. A coating solution is prepared using toluene as a solvent, a cast film is formed on a white PET (polyethylene terephthalate) substrate (thickness: 188 μm), and 20 parts by weight of PC3 is formed on the PVA intermediate layer. On the other hand, 20 parts by weight of n-octadecane was added and 80 parts by weight of polystyrene was added. A cast film is formed from a coating solution using toluene as a solvent, and 20 parts by weight of n-octadecane is added to 20 parts by weight of PC2 via an intermediate layer of PVA, and 80 parts of polystyrene is added. An image display medium was prepared by adding parts by weight, forming a cast film by a coating solution using toluene as a solvent, and further forming a PVA film as a protective layer. Since the display layer formed in this way is colorless and the color of the substrate is white, the produced image display medium was recognized as white by the observer.
When the display layer of this image display medium was irradiated with 366 nm ultraviolet light, all of PC2, PC3, and PC4 were colored and black. Further, when this was irradiated with white light, the display layer became colorless and transparent again, so that the image display medium was recognized as white.

This image display medium was again irradiated with 366 nm ultraviolet light to develop a color, and then a part thereof was irradiated with visible light having a center wavelength of 490 nm and a half-value width of 10 nm. Exhibited a bluish green color.
Further, when another part was irradiated with visible light having a center wavelength of 570 nm and a half-value width of 10 nm, PC3 was selectively decolored, and the irradiated part exhibited a bluish purple color. Further, when another portion was irradiated with visible light having a center wavelength of 610 nm and a half-value width of 10 nm, PC2 was selectively decolored and the irradiated portion was reddish purple. Further, when this was irradiated with white light, the display layer became colorless and transparent again, so that the image display medium was recognized as white.

This image display medium was again irradiated with 366 nm ultraviolet light to develop a color, and then a part thereof was irradiated with visible light having a center wavelength of 490 nm and a half-value width of 10 nm. Exhibited a bluish green color. Further, when another part was irradiated with visible light having a center wavelength of 570 nm and a half-value width of 10 nm, PC3 was selectively decolored, and the irradiated part exhibited a bluish purple color.
Further, when another portion was irradiated with visible light having a center wavelength of 610 nm and a half-value width of 10 nm, PC2 was selectively decolored and the irradiated portion was reddish purple. After that, when the heat treatment was performed at 40 ° C. with a heat roller, the portion that had been blue-green became blue, the portion that had been bluish purple became green, and the portion that had had red-purple color was red. Even if this image display medium was irradiated with white light (100,000 lux) for 1000 hours, there was no change in the image display medium. That is, it was confirmed that the association state was stably maintained even when irradiated with visible light for a long time.

(Example 17)
A display layer was also formed on the optical disc (100) in the same procedure as in Example 16. An image was formed on the optical disk (100) using the apparatus shown in FIG. First, when the display layer was irradiated with an ultraviolet LED (ultraviolet light irradiation means) (111), the display layer was colored black. An arbitrary image was formed by an LED having a liquid crystal shutter having a center wavelength of 610 nm and a half-value width of 10 nm and an LED having a center wavelength of 490 nm and a half-value width of 10 nm (126). A ceramic heater (second heating means) (125b) was heated to 40 ° C. to fix the image.
The optical disc (100) was irradiated with a fluorescent lamp at an illuminance of 700 lx for 1000 hours, but the display layer did not change. That is, it was confirmed that the association state was stably maintained even when irradiated with visible light for a long time. After that, when the heat treatment was temporarily performed at 80 ° C. by the ceramic heater (125a), the display layer returned to colorless.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive.
The scope of the present invention is shown not by the above description of the embodiment but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  The present invention can be used for so-called electronic paper, CD, DVD label surfaces, and the like.

It is a schematic diagram which shows the structure of the image display medium used for this invention. It is a schematic diagram which shows the relationship between the light absorbency of a photochromic compound, and a wavelength. 1 is a schematic diagram illustrating an image forming apparatus that forms a monochrome image on a sheet-like image display medium according to a first embodiment of the image forming apparatus of the present invention. FIG. 5 is a schematic diagram illustrating an apparatus for forming an image on an optical disc label recording surface according to a second embodiment of the image forming apparatus of the present invention. FIG. 5 is a block diagram illustrating an image forming apparatus according to a second embodiment of the present invention, in which an image recording apparatus of the present invention is provided in an optical disk drive device. It is a conceptual diagram of the recording track of a label recording surface. FIG. 9 is a schematic diagram illustrating an image forming apparatus that forms a monochrome image and erases a sheet-like image display medium according to a third embodiment of the present invention. FIG. 9 is a schematic diagram illustrating an apparatus for forming an image on an optical disc label recording surface according to a fourth embodiment of the image forming apparatus of the present invention. FIG. 10 is a schematic diagram illustrating an image forming apparatus that forms and deletes a monochrome image on a sheet-like image display medium according to a fifth embodiment of the present invention. FIG. 10 is a schematic diagram illustrating an apparatus for forming an image on an optical disc label recording surface according to a sixth embodiment of the image forming apparatus of the present invention. FIG. 10 is a block diagram illustrating an image forming apparatus according to a sixth embodiment of the present invention, in which the image recording apparatus of the present invention is provided in an optical disk drive device. FIG. 10 is a schematic diagram illustrating an image forming apparatus according to a seventh embodiment of the present invention, which performs multicolor image formation or monochrome image formation and deletion on a sheet-like image display medium. FIG. 10 is a schematic diagram illustrating an image forming apparatus according to an eighth embodiment of the present invention, which forms an image on an optical disc label recording surface.

Explanation of symbols

[About Figures 1 and 2]
DESCRIPTION OF SYMBOLS 1 Image display medium 10 Support base | substrate 11 Display layer 12 Display layer 13 Display layer [About FIG. 3, FIG. 7, FIG. 9 and FIG. 12]
DESCRIPTION OF SYMBOLS 1 Image display medium 20 Image forming apparatus 21 Insertion port 22 Conveyance roller 23 Conveyance roller 24 Ultraviolet light irradiation means 25 Heating means 25a First heating means 25b Second heating means 26 Visible light irradiation means 27 Paper discharge tray 29 Outlet 30 Sheet loading Table [About Fig. 4, Fig. 8, Fig. 10 and Fig. 13]
DESCRIPTION OF SYMBOLS 100 Optical disk 100a Optical disk label recording surface 110 Heating means 111 Ultraviolet light irradiation means 125a First heating means 125b Second heating means 126 Visible light irradiation means [About FIGS. 5 and 11]
DESCRIPTION OF SYMBOLS 100 Optical disk 111 Ultraviolet light irradiation means 111a Ultraviolet light irradiation means 120 Drive mechanism part 123 Spindle motor 124 Optical pick-up 125 Heating means 126 Visible light irradiation means 127 Feed part 128 1st analog process part 129 Servo process part 130 1st motor drive part 131 Controller 132 Laser driving unit 133 Digital signal processing unit 134 Buffer memory 137 Irradiation means driving unit 137a Visible light driving unit [about FIG. 6]
100 optical disc

Claims (13)

A photochromic composition comprising a photochromic compound represented by the following general formula (1) and a long-chain alkyl compound.

(However, R ₁ and R ₂ are each independently a long-chain hydrocarbon group having 18 or more carbon atoms. Z does not exist, or —CH ₂ OCO—, —NHCO—, —O—, —OCO— X is one of O, S, and C (CH ₃ ) _2. R _{3 to} R ₇ are independently hydrogen or a substituent, of which At least one is an electron withdrawing group, R _{9 to} R ₁₂ are independently hydrogen or a substituent, at least one of which is an electron donating group, R ₈ is hydrogen or It is a substituent.)   An image display medium, wherein a display layer made of the photochromic composition according to claim 1 is formed on a support substrate.   The image display medium according to claim 2, wherein the display layer contains two or more kinds of photochromic compounds having different hues in an associated state.   The display layer includes a first photochromic compound exhibiting a yellow hue in an associated state, a second photochromic compound exhibiting a magenta hue, and a third photochromic compound exhibiting a cyan hue. Item 3. The image display medium according to Item 2.   The display layer has a structure in which a display layer including only the first photochromic compound, a display layer including only the second photochromic compound, and a display layer including only the third photochromic compound are stacked. The image display medium according to claim 4.   An ultraviolet light irradiation means for partially irradiating the image display medium according to any one of claims 2 to 5 with ultraviolet light, and a heating means for raising the temperature of the display layer to a predetermined temperature necessary for color stabilization. An image forming apparatus comprising the image forming apparatus.   6. A rotation driving means for rotating the optical disk on which the display layer according to claim 2 is formed, an ultraviolet light irradiation means for partially irradiating the optical disk label recording surface with ultraviolet light, and color stabilization. An image forming apparatus comprising: heating means for raising the temperature to a predetermined temperature required for the image forming apparatus.   6. An ultraviolet light irradiation means for partially irradiating the image display medium according to claim 2 with ultraviolet light, and a first heating for raising the temperature of the display layer to a predetermined temperature necessary for color stabilization. And an image forming apparatus comprising: a second heating unit configured to raise the temperature of the display layer to a predetermined temperature necessary for erasing.   Rotation driving means for rotationally driving the optical disk on which the display layer according to claim 2 is formed, ultraviolet light irradiation means for partially irradiating the display layer of the optical disk label recording surface with ultraviolet light, An image comprising: a first heating means for raising the temperature of the display layer to a predetermined temperature required for color stabilization; and a second heating means for raising the temperature of the display layer to a predetermined temperature required for decoloring. Forming equipment.   6. An ultraviolet light irradiation means for irradiating the display layer with ultraviolet light on the image display medium according to claim 2, and visible light in a wavelength range corresponding to a maximum absorption wavelength of each photochromic compound in a colored state. An image forming apparatus comprising: a visible light irradiating unit that irradiates the display layer; and a heating unit that raises the temperature of the display layer to a predetermined temperature necessary for color stabilization.   6. A rotation driving means for rotating the optical disk on which the display layer according to claim 2 is formed, an ultraviolet light irradiation means for irradiating the display layer on the recording surface of the optical disk label with ultraviolet light, and color stabilization. A visible light irradiating means for irradiating visible light in a wavelength region corresponding to the maximum absorption wavelength of each photochromic compound in a colored state, and a heating means for raising the display layer to a predetermined temperature necessary for decoloring. An image forming apparatus.   6. An ultraviolet light irradiation means for irradiating the display layer with ultraviolet light on the image display medium according to claim 2, and visible light in a wavelength range corresponding to a maximum absorption wavelength of each photochromic compound in a colored state. Visible light irradiating means, first heating means for raising the display layer to a predetermined temperature necessary for color stabilization, and second heating means for raising the display layer to a predetermined temperature necessary for decoloring An image forming apparatus comprising:   A rotation driving means for rotating the optical disk on which the display layer according to any one of claims 2 to 5 is rotated, an ultraviolet light irradiation means for irradiating the display layer on the optical disc label recording surface with ultraviolet light, Visible light irradiating means for irradiating visible light in a wavelength range corresponding to the maximum absorption wavelength of each photochromic compound, first heating means for raising the display layer to a predetermined temperature necessary for color stabilization, and decolorization An image forming apparatus comprising: a second heating unit configured to raise the temperature of the display layer to a necessary predetermined temperature.

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