JPH03280054A - Photosensitive thermosensitive recording material - Google Patents

Abstract

PURPOSE:To allow high-speed recording and continuous gradation with low energy and to obtain high resolution images by forming the latent images of images by light energy and subjecting dyes to color development by thermal transfer to obtain the images. CONSTITUTION:A microcapsule layer 8 formed by dispersing porous microcapsules 3 which contain a dye precursor 4, a polymerizable monomer 5 to be cured by light energy and a photopolymn. initiator 6 and are synthesized by an in situ polymn. method or making combination use of the in situ polymn. method and coacervation method into a binder is constituted on one surface of a base 2. The porous microcapsules 3 transmit the dye precursor contg. therein when impressed with heat energy. The polymerizable monomer 5 can control the transmission quantity of the dye precursor 4 released from the porous microcapsules 3 by a difference in the degree of polymn. by photoirradiation. The thermal transfer is executed on the recording sheet provided with a color developer layer on a base, such as paper, in such a manner, by which the ground fogging is obviated and the continuous gradation is possible. The high-quality image is thus obtd.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a light and heat sensitive recording material that can be used in printers and copying machines as outputs of computers, etc. The present invention relates to a light- and heat-sensitive edge recording material that allows for digital recording.

[Summary of the invention]

In the present invention, a color developer layer in which a color developer that reacts with a dye precursor to develop color from the dye precursor is dispersed in a binder is provided on one side of a support such as paper. Porous microcapsules containing a dye precursor, a polymerizable polymer, and a photopolymerization initiator are synthesized on a support using a +n 5 itu polymerization method or a combination of an in 5 itu polymerization method and a core cell basis method, and then incorporated into a binder. This is a light- and heat-sensitive recording material that records by thermal transfer using a heat-sensitive transfer sheet provided with a dispersed microcapsule layer. By irradiating this microcapsule layer with visible light or ultraviolet light to draw a latent image of the image, and then thermally transferring it using a roller, infrared rays, or thermal head, continuous VTLI toning is possible and a high-quality recorded image is created. The purpose is to obtain.

C. Prior Art] Conventional heat-sensitive recording materials are generally those in which thermochromic dyes are coated on a support such as paper and then colored by heat from a thermal head or the like for recording. Furthermore, carbonless paper is a typical recording material to which microcapsules are applied, and the resolution depends on the pressurized area of a pressurized object such as a ballpoint pen.

In addition, as a recording material that applies light energy and microcapsules, Japanese Patent Application Laid-Open No. 58-88739 and Japanese Patent Application Laid-Open No. 58-17432 disclose a photosensitive and pressure-sensitive recording sheet that uses light to create a latent image of an image using high pressure. By destroying the microcapsules, the contents of the microcapsules are released, and the dye reacts with a color developer to develop color and produce an image.

Further, in Japanese Patent Application Laid-Open No. 60-214990, after an image is formed by heat, the image is fixed and recorded by curing the photocurable resin inside the uncolored microcapsules with light energy.

[Problem to be solved by the invention]

With conventional recording materials using thermochromic dyes, it is difficult to express gradation without using a pseudo gradation method such as a dither method, and natural color development of the dye has been a problem during long-term storage.

In addition, with photosensitive and pressure-sensitive recording sheets, since the microcapsules are destroyed with high pressure, there are problems such as unevenness in images due to uneven pressure in the pressurized area, increased size of the device, and inability to record at high speed. there were. In the fixing type using light energy, the resolution of the image depends on the heating element that is the thermal energy source, so there is a problem that a high-resolution image cannot be obtained.

[Means to solve the problem]

In order to solve the above problems, in the present invention, a latent image of an image is formed using light energy, and a dye is colored by thermal transfer to obtain an image, thereby enabling high-speed recording and continuous gradation with low energy. The object of the present invention is to provide a light and heat sensitive recording material that can obtain high resolution images.

[For production]

The porous microcapsules of the photosensitive and thermosensitive recording material of the present invention contain a dye precursor and a polymerizable monomer,
i3 a M! from the porous microcapsules of the dye precursor depending on the degree of polymerization of the polymerizable monomer in the porous microcapsules by light irradiation. is controlled to enable continuous gradation expression.

Therefore, ultraviolet or visible light corresponding to an image signal from a CRT or the like is irradiated onto the light and heat sensitive recording material 4 of the present invention, and a latent image corresponding to the image signal is formed on the polymerizable layer. Using heat from a thermal head or infrared rays, an amount of dye precursor corresponding to the image signal passes through the porous microcapsules and is transferred to the recording sheet, where it reacts with the color developer in the color developer layer to develop color and produce a continuous layer. This achieves high-quality image recording.

〔Example〕

This will be explained below based on the drawings. The first is a schematic cross-sectional view showing a heat-sensitive transfer sheet in the present invention. FIG. 2 is a schematic cross-sectional view showing the exposure state of the heat-sensitive transfer sheet, and FIG. 3 is a schematic cross-sectional view showing the heat-sensitive transfer state. In the present invention, polyethylene terephthalate (
A dye precursor 4 is placed on one side of a support 2 such as a PET) film, and a polymerizable adhesive that is cured by light energy is placed on one side of a support 2 such as PET) film.
A microcapsule layer 8 was provided in which porous microcapsules 3 containing 5 and a photopolymerization initiator 6 and synthesized using an in 5 in situ polymerization method or a combination of an in 5 in itu polymerization method and a coacelhesion method were dispersed in a binder. The structure is as follows.

Here, the porous microcapsules 3 have the effect of transmitting the dye precursor contained therein by applying thermal energy, and the polymerizable monomer 5 contained in the porous microcapsules 3 is irradiated with light. Since the amount of permeation of the dye precursor 4 released from the porous microcapsules 3 can be controlled by the difference in the degree of polymerization, this has the effect of controlling the amount of permeation of the dye precursor 4 depending on the irradiated light energy.

When the microcapsule layer 8 is irradiated with irradiation light 9 such as ultraviolet rays or visible light corresponding to an image signal from a CRT or the like, the polymerizable monomer 5 is polymerized according to the energy and released from the porous microcapsule 3. Dye precursor 4
It becomes possible to control the amount of permeation. When heated by the heating element 16, the binder 7 in the microcapsule layer 8
is melted, and the dye precursor 4 whose permeation amount is controlled depending on the degree of polymerization of the polymerizable monomer 5 is released from the porous portion of the porous microcapsule 3, and the dye precursor 4 is released from the porous portion of the porous microcapsule 3, and the dye precursor 4 is released from the porous portion of the porous microcapsule 3, and the dye precursor 4 is released from the porous portion of the porous microcapsule 3. It is transferred to layer 12 and reacts with the color developer 1) in the color developer layer to develop color. Therefore, color development of the dye corresponding to the energy amount of the irradiated light 9 is observed in the color developer layer 12, and a continuous gradation high-quality image is recorded.

In the present invention, melamine-
Examples include formalin resin, urea-formalin resin, and the like. In addition, examples of constituent materials of the porous microcapsule film using the core cell basis method include styrene-butadiene resin, styrene-maleic anhydride resin, and the like.

As the dye precursor, leuco type dyes can be used, such as crystal violet lactone, rhodamine B lactam, malachite green, 3-dialkylamino-7-dialkylamylfluoran, and hengeine leucomethylene blue.

In addition, color developers for coloring leuco dyes as dye precursors include aromatic carboxylic acid metal salts such as salicylic acid and its derivatives, acid clay, activated clay, clays such as hentonite, α-naphthol, Bisphenol A
Phenol compounds such as the following can be used.

As the binder, polyvinyl alcohol, polyethylene glycol, carboxyl methylcellulose, styrene-maleic anhydride copolymer, styrene-butadiene latex, etc. can be used.

Polymerizable monomer is the main component in porous microcapsules and is also used as a solvent to dissolve dye precursors and photopolymerization initiators. It is necessary to have the ability to smoothly release the dye precursor from the porous microcapsules when the dye precursor is applied. In addition, the size of porous microcapsules is determined by emulsifying the capsule liquid in water, so in addition to the polymerizability of the liquid as a solvent, the insolubility of the filler in water is also an important factor. There is one. If an effective polymerizable monomer is solid at room temperature, it can be used in combination with other polymerizable monomers that are liquid at room temperature. It is also possible to dissolve polymerizable monomers that are solid at room temperature in water-insoluble oils (such as diisopropylnaphthalene), although they do not exhibit polymerizability, but in this case, they do not completely polymerize. However, there is a problem in that the dye precursor oozes out from the porous microcapsules without being completely cured. As effective polymerizable polymers, there may be used polymers having at least two or more ethylenically unsaturated groups in the molecule and polymers having ethylenically unsaturated groups at the ends or side chains. Compounds included in these include polyesters having acrylate or methacrylate terminals, epoxy resins having acrylate or meccrylate terminals, and acrylic esters or methacrylic esters of polyhydric alcohols. Specifically, the compounds included in these include diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, polyethylene glycol diacrylate, and polyethylene glycol. Dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritol In addition to hexaacrylate, dipentaerythritol hexamethacrylate, ethylcarpitol acrylate, ethylcarpitol methacrylate, phenoxyethyl acrylate, fenoquine ethyl methacrylate, and the like, the following acrylates can be mentioned.

A A (M N)nM A , A (
X Y) nX-A where A Niacrylic acid, M:2
Hydrolic alcohol, N: dibasic acid, X: polyhydric alcohol, Y
: It is a polybasic acid.

As the photopolymerization initiator, quinone, acyloin, diazoanthrone, diazonium salt, diazophenanthrone, disulfide, aromatic azide, aromatic ketone, aromatic azosulfonate, aromatic carbazide, etc. can be used.

Examples of the present invention are shown below, but the present invention is not limited thereto.

(Preparation of recording paper) A color developer liquid in which 20 parts by weight of each of bisphenol A and silica powders were dispersed in an aqueous solution of 5% (W/W) polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.) using a ball mill. was coated onto a support such as paper using a bar coater (Har Coater-20, manufactured by Yoshimitsu Seiki Co., Ltd.) to prepare a recording paper.

(Prepolymer preparation) Add 1 part of melamine to 30 parts by weight of 37% formaldehyde aqueous solution.
0! ! of the mixture was added, reacted at 60°C for 15 minutes, and then
1 part by weight of glycine was added and reacted for 1 minute to obtain an aqueous prepolymer solution. Even if this prepolymer aqueous solution is left to stand, polymerization may proceed naturally and it may harden, so it is necessary to encapsulate it immediately after preparation.

(Example 1) 2 parts by weight of a leuco dye that develops a magenta color was heated and dissolved in 25 parts by weight of trimethylolpropane triacrylate (TMPTA), and 1 part by weight of benzoin methyl ether was further dissolved to prepare a capsule-enclosed liquid. This capsule liquid was mixed with 200 parts by weight of water adjusted to pH 4, and emulsified and dispersed using a homogenizer at sooorpm for about 5 minutes.

This dispersion was stirred with a mechanical stirrer and heated to 60°C in a hot water bath, and the previously prepared melamine-formalin resin prepolymer was added dropwise, and stirring was continued for about 3 hours while maintaining the temperature at 60°C. At this time, if the prepolymer is not adjusted and dropped quickly, the prepolymer may become polymerized and cannot be encapsulated.

From the porous microcapsule dispersion thus obtained,
Porous microcapsules were separated by a centrifugal separator. This porous microcapsule was mixed with 5% (W) of the same amount of polyvinyl alcohol (Kuraray Bobal 1) 7: manufactured by Kuraray
/W) It was dispersed in an aqueous solution and applied onto a PET film using a bar coulter to obtain a heat-sensitive transfer sheet.

Characteristics of the produced light and heat sensitive recording materials were evaluated using a 300W xenon seat arc lamp (manufactured by Ushio Inc.: UYX-
300) is used to irradiate the thermal transfer sort to form a latent image of the image.
Thermal transfer was performed on a recording sheet using Ml>, and the resulting image was used.

As a result, an image was formed on the recording notebook according to the light irradiation time, and continuous tone recording was also possible. In addition, in areas where color development was not required, the polymerizable monomer was cured by light irradiation and the dye was in a state where no color development occurred, so it was possible to obtain a good image without background fading.

[Example 2] In Example 1, a leuco dye that develops a cyan color was used instead of the leuco dye that develops a magenta color, and 0.2 parts by weight of benzophenone and 0.5 parts by weight of Michler's ketone were used instead of benzoin methyl ether. Using the same method, porous microcapsules were synthesized and coated on a PET film to prepare a heat-sensitive transfer sheet.

As a result of evaluating the characteristics against light irradiation, it was possible to obtain a high-quality image with continuous gradation as in Example 1.

[Example 3] The same method as in Example 1 was carried out except that the leuco dye that develops a yellow color was used instead of the leuco dye that develops a magenta color, and 1.0 parts by weight of dl-camphorquinone was used instead of benzoin methyl ether. Porous microcapsules were synthesized and coated on a PET film to make a heat-sensitive transfer sheet. As a result of evaluating the characteristics against light irradiation, it was possible to obtain a high-quality image with continuous gradation as in Example 1.

[Example 4] 2 parts by weight of a leuco dye that develops a magenta color was dissolved by heating in 25 parts by weight of trimethylolpropane triacrylate (TMPTA), and 1 part by weight of benzoin methyl ether was further dissolved to prepare a capsule-enclosed liquid. This capsule liquid was mixed with 200 parts by weight of a 3% aqueous solution of styrene-maleic anhydride copolymer adjusted to pH 8, and emulsified and dispersed at 5000 rpm for about 5 minutes using a homogenizer.

This dispersion was stirred with a mechanical stirrer and heated to 60° C. in a water bath, and the melamine-formalin resin prepolymer prepared previously was added dropwise.

The pH was adjusted to 4 with a dilute aqueous hydrochloric acid solution, and stirring was continued for about 3 hours while maintaining the temperature at 60°C. By adjusting the pH to 4, the styrene-maleic anhydride copolymer is precipitated around the emulsion according to the principle of the coacelation method, and a capsule film is quickly formed. It is then completely encapsulated using an in 5 situ polymerization method.

Thereafter, porous microcapsules were obtained in the same manner as in Example 1. As a result of evaluating the characteristics with respect to light irradiation, it was possible to obtain continuous gradation as in Example 1. Regarding the background fog, better results than in Example 1 could be obtained.

〔Effect of the invention〕

The present invention provides porous microcapsules synthesized on a support such as a PET film by combining a dye precursor, a photopolymerization initiator, and a polymerizable monomer using a 1 nsitu polymerization method or an in 5 situ polymerization method in combination with a core cell vane run method. By thermally transferring from a heat-sensitive transfer sheet with a porous microcapsule layer encapsulated in a binder and provided with a layer of porous microcapsules dispersed in a binder to a recording sheet with a color-developing layer on a support such as paper,
It is possible to provide a high-quality light and heat-sensitive recording material that is capable of continuous gradation without background blur.

[Brief explanation of the drawing]

FIG. 1 shows a schematic cross-sectional view of the heat-sensitive transfer sheet of the present invention, FIG. 2 is a schematic cross-sectional view showing the exposure state of the heat-sensitive transfer sheet of FIG. 1, and FIG. It is a sectional view showing a state. 1...Thermal transfer sheet 2...Support 3...Porous microcapsules 4...Dye precursor 5...Polymerizable monomer 6...Photopolymerization initiator 7・・ ・Binder 8...Microcapsule layer 9...Irradiation light 10...Photocured microcapsules 1)...
Color developer 12...Developer layer 13...Support 14...Color development section 15...Recording paper

Claims (5)

[Claims] (1) A porous layer containing a color developer layer that reacts with a dye precursor to develop color on one side of the support, and a dye precursor, a polymerizable monomer, and a photopolymerization initiator on another support. Microcapsules are synthesized by an in situ polymerization method or by a combination of an in situ polymerization method or a coacervation method, a microcapsule layer dispersed in a binder is provided, and the dye precursor is colored by thermal transfer. A light and heat sensitive recording material characterized by: (2) The photosensitive and thermosensitive recording material according to claim 1, wherein the capsule membrane material of the porous microcapsules synthesized by the in situ polymerization method is selected from the following combinations of compounds. [1] Melamine-formalin [2] Urea-formalin (3) The light and heat sensitive recording material according to claim 1, wherein the porous microcapsule membrane material in the coacervation method is selected from the following compounds. [1] Styrene-butadiene copolymer [2] Styrene-maleic anhydride copolymer [3] Gelatin [4] Gelatin-gum arabic system (4) The light and heat sensitive recording material according to claim 1, wherein the dye precursor is a leuco dye. (5) The light and heat sensitive recording material according to claim 1, wherein the polymerizable monomer is a compound that is crosslinked and cured by light energy.