JPH0619127A - Microcapsule - Google Patents

Abstract

PURPOSE:To prevent the breakage of microcapsules during handling or applying by including an image forming material, a photosensitive material to be cured by light energy and a thickener which does not react with both into the microcapsules. CONSTITUTION:The microcapsule 1 consists of a shell part 2, a liquid component 3 therein and the thickener 4. The microcapsule contains, as the liquid component 3, a color developing material, such as dye or pigment or the image forming material, such as die precursor which develops a color by reacting with a color developer, etc., and the photosetting material which cures by sensing a certain wavelength. The thickener 4 does not react with the image forming material and the photosensitive material. Since the microcapsule 1 internally contains the thickener 4, the viscosity is high and, therefore, its internal resistance increases during the course of an electrostatic application operation and the microcapsule is hardly broken by the pressure applied thereon at the time of applying the microcapsule. Then, the breakage of the microcapsule is prevented even during the handling thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive microcapsule used in copying machines and printers.

[0002]

2. Description of the Related Art Conventionally, a photosensitive sheet coated with microcapsules encapsulating a dye precursor and a photo-curable substance is exposed based on image information by using an exposing means, and the microcapsules are exposed based on the image information. After curing, the microcapsules that have not been cured are crushed by pressure development in a state of being in close contact with a support such as plain paper coated with a color developing agent that reacts with the dye precursor encapsulated in the microcapsules. An image forming apparatus has been put into practical use in which an image is formed by reacting a dye precursor flowing out from a microcapsule with a roller and a color developer.

Further, since the image forming apparatus requires a developer because it uses a dye precursor, Japanese Patent Application No. 3-12491, which the applicant of the present invention has already filed.
In Japanese Patent Application Nos. 9-124920 and 3-124921, there is proposed an image forming apparatus using a colored micropsel toner containing a dye or a pigment which does not require a developer. . In this method, colored microcapsule toner is applied to an endless belt, a photoconductor, an image receiving paper, etc., and then exposed and pressure developed according to image information to form an image on plain paper.

[0004]

However, in such an image forming apparatus, there is a problem that the capsules are broken at the time of handling the microcapsules or applying the microcapsules.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a microcapsule which is not destroyed or is hardly destroyed during handling or application of the microcapsule.

[0006]

In order to achieve this object, the microcapsule of the present invention is formed with an image of a dye precursor or the like which changes color at least by reacting with a color-forming substance such as a dye and a pigment or a developer. It is characterized by containing a material, a photosensitive substance which is cured by light energy, and a thickener which does not react with the image forming material and the photosensitive substance.

[0007]

In the microcapsule of the present invention having the above structure, the viscosity of the encapsulated substance is improved by the contained thickener, and as a result, the elastic force of the microcapsule is improved and the capsule is less likely to be broken. Therefore, the microcapsules are not destroyed or extremely rare during handling or coating.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an enlarged sectional view of a microcapsule embodying the present invention. The microcapsule 1 includes an outer shell 2, a liquid component 3 inside the outer shell 2, and a thickener 4.

The liquid component 3 contains at least an image-forming material such as a dye or a pigment and a photo-curable substance which cures in response to a certain wavelength.

As the image forming material, a dye precursor or the like that changes color by reacting with a dye, a pigment, a color developer or the like can be used. As the dye, xanthene-based, coumarin-based, merocyanine-based, thiazine-based, azine-based, methine-based, oxazine-based, phenylmethane-based, cyanine-based, azo-based, anthraquinone-based, pyrazoline-based, stilbene-based, quinoline-based, phthalocyanine-based, Examples thereof include leuco dyes, and examples of pigments include inorganic pigments such as carbon black, yellow lead, red iron oxide, titanium oxide, and molybdenum red, and organic pigments. Further, as the dye precursor, a diphenylmethane compound, a triphenylmethane compound, a bisphenylmethane compound, a xanthene compound, a thiazine compound,
Fluoran compounds, spiropyran compounds, etc. and mixtures thereof can be used. When the dye precursor is used as the image forming material, it is necessary to use the color developer as the absorbing layer.

The photosensitive substance is a resin which is sensitive to light and hardens, and is usually used by mixing a photoinitiator and a polymerizable substance. The photoinitiator is one which is sensitive to light and initiates the polymerization of the resin, and for example, benzophenone, benzoylalkyl ethers such as benzoylisopropyl ether, Michler's ketone, metal arene compound, 2,4-
Diethyl thioxanthone etc. can be mentioned.

Examples of the polymerizable substance include N-vinyl-2-pyrrolidone, bisphenol A diacrylate and methacrylate, tripropylene glycol diacrylate and methacrylate, polyethylene glycol diacrylate and methacrylate, pentaerythritol triacrylate and methacrylate,
Examples include dipentaerythritol hexaacrylate and methacrylate, trimethylolpropane triacrylate and methacrylate, oligoester acrylate and methacrylate, and the like. Further, these polymerizable compounds may be used alone or as a mixture of two or more kinds.

As the thickener 4, there are an aqueous system and a non-aqueous system. When the liquid component 3 is water-soluble, it is necessary to select an aqueous system and when it is oil-soluble, it is necessary to select a non-aqueous system. Thickener 4
Are roughly classified into inorganic type and organic type both in water type and non-aqueous type, and both can be used. Specific examples of the aqueous system include hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, sodium alginate, casein, sodium caseinate, xanthan gum, polyvinyl alcohol, montmorillonite and the like. Examples of the non-aqueous system include aluminum stearate, zinc stearate, aluminum octylate, fatty acid amide, polyethylene oxide, dextrin fatty acid ester, dibenzylidene sorbitol, organic bentonite, silica and the like.

The thickener 4 is added so that the liquid component 3 has a viscosity of several hundred to several hundred thousand cps. Further, when used in an image forming apparatus as shown below, it is 500 to 10
000 cps is more preferable.

The microcapsule 1 having the above structure can be manufactured by a method which has already become a known technique in the art. For example, US Pat. No. 2,800,457.
No. 2,400,458 and the like, a method of phase separation from an aqueous solution as described in JP-B-38-1974 and JP-A-4
No. 2-446, No. 42-771, etc., interfacial polymerization method, JP-B-36-9168, JP-A-51.
I by polymerization of monomers shown in Japanese Patent Publication No. 9079
n-situ method, British Patent Nos. 952807 and 96
Although there is a melt dispersion cooling method and the like shown in the specification of 5074, it is not limited to this.

As the material for forming the outer shell 2, gelatin, gum arabic, starch, sodium alginate, polyvinyl alcohol, polyethylene, polyamide, polyester, polyurethane, polyurea, polyurethane,
Polystyrene, nitrocellulose, ethyl cellulose,
Methyl cellulose, melamine-formaldehyde resin,
A urea-formaldehyde resin or the like is used, but a material that allows sufficient light transmission is more preferable.

Next, the microcapsule 1 having the above structure is
An example used in an image forming apparatus will be described with reference to the drawings.

FIG. 2 is a schematic sectional view of an image forming apparatus 60 using the microcapsules 1.

Inside the image forming apparatus 60, a capsule holding member 44, a microcapsule applying section 20 for applying the microcapsule 1 to the capsule holding member 44, an exposing section 10, and a transfer member 45 are provided.

Capsule holding member 44 and transfer member 4
5 are both columnar or cylindrical in shape, and the size thereof is not limited, but for example, diameter 30 mm to 200
Length in mm (length in the direction perpendicular to the paper surface in Fig. 2) 3
It is about 00 mm. Furthermore, since the holding member 44 and the transfer member 45 need to withstand the pressure applied to break the microcapsules, at least the core portion is preferably made of metal such as stainless steel or aluminum. If necessary, a resin material for adding a function may be coated or bonded around the core portion. The region sandwiched between the capsule holding member 44 and the transfer member 45 constitutes the destruction portion 42 of the microcapsule.

The exposure unit 10 is composed of an exposure lamp 11, a document table glass 15, a document cover 13, a filter 14 for adjusting a color tone of an image, and a light shielding plate 19.

The microcapsule coating section 20 is provided to dry-coat the holding member 44 with microcapsules, and a case 21 for storing the microcapsules 1, a stirrer 23, and a carrier 25 carrying the microcapsules 1 are provided. And a supply body 24 for supplying the microcapsules to the support body 25. Here, the microcapsule 1 is held between the holding member 44 and the carrier 25 by a DC or AC power supply (not shown).
An electric field for moving from 5 to the holding member 44 is formed.

Next, the operation of this device will be described.

When a start switch (not shown) is turned on,
The holding member 44 starts rotating in the direction of the arrow in the figure.

In the microcapsule coating section 20, the microcapsule 1 is charged and carried on the carrier 25 by the rotation of the agitator 23 and the feeder 24. The carried microcapsule 1 includes the holding member 44 and the carrier 25.
An electrostatic attraction is applied in the direction of the holding member 44 by the electric field formed between the two. As a result, the microcapsules 1 move toward the holding member 44 and adhere to the holding member 44 by electrostatic force. That is, the powdery microcapsules 1 are applied to the holding member 44.

During the electrostatic coating operation described above, the microcapsule 1 has a high viscosity because it contains a thickener inside. Therefore, the internal resistance increases, and the microcapsules are hardly broken at a pressure applied to the microcapsules. Therefore, even during capsule handling
It will not be destroyed. However, since the viscosity inside the capsule is only improved, the capsule is broken immediately when a certain pressure or more is applied.

The holding member 44 coated with the microcapsules 1 rotates in the direction of the arrow in the figure, and the microcapsules 1 are conveyed to the lower part of the exposure unit 10. At this point, the halogen lamp 11 of the exposure unit 10 is turned on, and the original platen glass 15 supporting the original 12 is moved. As a result, the exposure operation is performed according to the original 12. The light reflected from the original 12
An image is formed on the surface of the microcapsule 1 applied to the holding member 44 through the filter 14 for adjusting the color tone of the image.

The microcapsules 1 thus exposed according to the image information are cured because the liquid component 3 undergoes a polymerization reaction according to the degree of the exposure energy.

Further, the microcapsule 1 has a destruction portion 42.
Be transported to. Here, the microcapsule 1 is
It is sandwiched between the holding member 44 and the transfer member 45 and pressed. Among the pressurized microcapsules, the microcapsules 1 to which the degree of exposure by the exposure is weak are destroyed and the image forming material or the like flows out according to the exposure amount. At this time, since the microcapsule 1 and the transfer member 45 are in contact with each other, the effluent is transferred to the transfer member 45.

The image receiving paper 52 such as plain paper is supplied to the paper feeding cassette 5.
1 and is sent between the transfer member 45 and the heat roller 55.

When the image receiving paper 52 and the transfer member 45 are heated by the heat roller 55, the image forming material and the like attached to the transfer member 45 are transferred to the image receiving paper 52. As a result, an image is formed and fixed on the image receiving paper 52, and the image is ejected to the outside of the apparatus.

The microcapsules that have been completely exposed by the imagewise exposure remain unbroken and remain on the holding member 44 because the liquid component 3 is polymerized, and are peeled off from the holding member 44 by the blade 31 of the cleaning unit 30 and collected. To be done.

The above-described present invention is not limited to the above-described embodiments, but can be modified within the scope of the invention.

For example, although the microcapsules are dry-coated on the holding member in this embodiment, they may be wet-coated.

[0036]

As is apparent from the above description,
In the microcapsules of the present invention, the microcapsules are not destroyed or extremely rare during handling or application.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a microcapsule of the present invention.

FIG. 2 is a schematic sectional view of an image forming apparatus using the microcapsules of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microcapsule 2 Outer shell 3 Liquid component 4 Thickener 20 Microcapsule application part 44 Holding member 45 Transfer member

Claims (1)

[Claims] 1. An image forming material such as a dye precursor which changes color by reacting with a coloring substance such as a dye or a pigment or a color developing agent, a photosensitive substance which is cured by light energy, and the image forming material and A microcapsule containing a photosensitizer and a thickener that does not react with the photosensitive substance.