JPH05165248A - Microcapsule manufacturing method and image forming apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a method for producing a photosensitive microcapsule for obtaining a clear image without stains, and an image forming apparatus using the photosensitive microcapsule toner. [Structure] A method for producing a microcapsule comprises s / o / microcapsules containing magnetic particles and a photosensitive substance.
It is manufactured using w emulsion. In the image forming apparatus, a magnetic pole is provided on at least a part of a member that holds and conveys the microcapsule toner, and does not transfer unnecessary toner to the image receiving paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing microcapsules containing at least a photosensitive substance and an image forming apparatus using the microcapsules.

[0002]

2. Description of the Related Art Conventionally, a toner composed of microcapsules in which a photosensitive material consisting of a pigment body such as a face wash and a photocurable material is contained in the outer wall of a resin, and the mechanical strength of which is changed in response to light has been known. Japanese Patent Laid-Open No. 3-77961 and Japanese Patent Laid-Open No. 3-8
It is disclosed in Japanese Patent No. 0258. Further, using the toner composed of the microcapsules, after exposing the toner, only the weak toner is destroyed by pressure or the like,
An image forming apparatus for forming an image on an image receiving paper by letting out the encapsulated dye body and transferring it to the image receiving paper is disclosed in Japanese Patent Application Laid-Open No. HEI 3 (1998)
No. -80258 and Japanese Patent Laid-Open No. 3-92856.

In this image forming apparatus, a toner application mechanism for charging the toner, holding it on a carrier and adhering it to a support by electrostatic force, means for exposing microcapsule toner according to image information, and the pigment body It has a capsule breaking means for spilling. The application mechanism applies microcapsule toner to the holding member. Next, among the microcapsule toners image-exposed by the exposing means, the microcapsule toners which have not been photo-cured are destroyed by the destroying means and the inclusions such as pigment bodies flow out, so that the image is received on the image receiving paper. It is formed.

[0004]

However, in these image forming apparatuses, the adhesive force between the holding member and the microcapsule toner is weak, so that the microcapsule toner unnecessary for the image cured by the imagewise exposure is also included. It was transferred to the image receiving paper. It is obvious that the image is disturbed when the unnecessary toner is attached in this manner. In particular, when a color pigment is contained in the toner inclusion, it is a serious defect. The present invention has been made in order to solve the above-mentioned problems, and manufactures a microcapsule toner capable of forming a good image without adhering originally unnecessary capsule toner to an image receiving paper. A method and an image forming apparatus are provided.

[0005]

The method for producing microcapsules according to the present invention is a method for producing microcapsules containing at least a magnetic substance and a photosensitive substance as an encapsulation material. Using a so-called s / o / w complex emulsion in which a dispersed phase surrounded by an oil-soluble substance (o) composed of a soluble substance is emulsified in a water-soluble continuous phase (w), Alternatively, the outer wall material of the microcapsule is added to both phases.

Further, the image forming apparatus of the present invention uses a microcapsule toner containing at least a magnetic substance and a photosensitive substance, and pressurizing means for causing the photosensitive substance to flow out, and the microcapsule toner in the pressurizing means. An image forming apparatus having holding means for supplying a magnetic material, wherein the holding means is provided with a magnetic pole for holding a magnetic material.

[0007]

According to the above-mentioned method for producing microcapsules, s
In the / o / w complex emulsion, a resin is formed around the dispersed phase by interfacial polymerization or in-situ polymerization and becomes the outer wall of the microcapsule.

Therefore, microcapsules having the magnetic particles and the oil-soluble substance as the inclusions and the resin as the outer wall are formed in the water-soluble continuous phase. Then, the water of the continuous phase is evaporated or sublimated to obtain microcapsule powder.

The powder of the microcapsules is hereinafter referred to as (photosensitive) microcapsule toner.

In the image forming apparatus of the present invention having the above structure, first, the magnetic substance of the microcapsule toner is attracted to the magnetic pole provided on the holding member.
The microcapsule toner is held by the holding member. Since the holding member moves, the microcapsule toner is supplied to the pressing means. The microcapsule toner is sandwiched between the holding member and the transfer member and pressed by the pressing means. When pressurized, the unexposed and therefore uncured microcapsules are destroyed. The photosensitive substance, which is an oil-soluble substance, out of the contents of the destroyed microcapsules flows out and adheres to the transfer body. On the other hand, the magnetic substance in the inclusion is attracted to the holding member by the magnetic force, and thus remains in the holding member.

The exposed or cured microcapsules are not destroyed by the pressure, and thus are retained in the retaining member by the magnetic force as they are cured.

The photosensitive substance attached to the transfer body is transferred to the image receiving paper by thermal transfer or the like later. Since the photosensitive material contains a coloring matter such as a dye or pigment, an image is formed on the image receiving paper.

Therefore, the image receiving paper contains only the pigment bodies necessary for the image, and does not contain unnecessary microcapsule toner.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a microcapsule manufactured by an embodiment of the manufacturing method of the present invention. Figure 1
In, the microcapsules 1 are substantially spherical particles, and the diameter thereof can be freely set within the range of 0.1 to 100 microns depending on the manufacturing conditions, but in this embodiment, it is about 10 microns.

In this microcapsule 1, one or a plurality of magnetic particles 2 having a diameter of 0.1 to 2 microns and an oil-soluble substance 3 surrounding the particles are included as an inclusion, and the inclusion is a resin. It is enclosed by an outer wall 4 consisting of. The thickness of the outer wall 4 is usually 0.1 to 1 micron. The oil-soluble substance 3 is obtained by dissolving or mixing a photopolymerization initiator, a wavelength sensitizer, and a pigment powder for coloring in an oil-soluble liquid of a monomer of a polymerizable compound. That is, this oil-soluble substance is a photosensitive substance that reacts with light to cause a polymerization reaction.

FIG. 2 is a process chart of one embodiment of the method for producing microcapsules of the present invention. An s / o / w emulsion is prepared, and the aqueous phase, which is the continuous phase of this emulsion, is added to the microcapsule wall. It is a flow figure explaining the method of manufacturing a microcapsule by adding the aqueous solution of the reactant used as material.

First, an oil-soluble liquid to be the dispersed phase of the emulsion is prepared. First, magnetic particles are mixed with the oil-soluble substance.

As the magnetic particles, fine powders of iron, cobalt, nickel, alloys or oxides containing these as main components, or various ferrites are used.

The photosensitive material mixed with the magnetic particles is stirred for homogenization, and as a result, the individual magnetic particles are dispersed in the oil-soluble solution. This is called a dispersion.

On the other hand, a protective colloid aqueous solution which will be the continuous phase of the emulsion later is prepared. The protective colloid aqueous solution may be prepared by dissolving the protective colloid substance in pure water. Examples of the protective colloid substance include gelatin, gum arabic, casein, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, and ethylene-maleic anhydride copolymer. A natural or synthetic hydrophilic polymer substance such as coalesced is used.

The protective colloid aqueous solution and the dispersion are mixed. Then, when the mixed liquid is stirred by a commercially available homogenizer or an emulsifier, minute droplets of the dispersion liquid in which the magnetic particles are surrounded by the oil-soluble liquid are formed in the continuous aqueous protective colloid solution. Emulsified into. That is, an s / o / w complex emulsion is created. Here, the size of the droplets of the dispersion liquid has a strong influence on the size of the microcapsules to be produced. In order to obtain the desired size of microcapsules, the speed of stirring may be adjusted.

Next, an aqueous solution of the reactant which becomes the material for the outer wall of the capsule is added to this emulsion. The preparation of this solution is usually done prior to the preparation of said emulsion. As the reactant used here, a mixture of an organic amine, an acid amide and a water-soluble epoxy compound, a prepolymer of urea and formaldehyde, a mixture of urea and formaldehyde and polyacrylic acid, a mixture of an aminoplast resin prepolymer and a surfactant, Examples include a prepolymer of melamine and formaldehyde, a mixture of a heterocyclic amine and an aldehyde, and the like.

The emulsion, to which the aqueous solution of the reactant is added, is adjusted in temperature and pH value so that a resin as an outer wall material is formed from the reactant, and is stirred for several hours.

As a result, the resin reacted with the reactant is produced around the minute droplets of the dispersion liquid. Therefore, microcapsules having the magnetic particles and the oil-soluble liquid composed of a photosensitive substance surrounding the magnetic particles as an inclusion and a resin as an outer wall are generated.

The liquid produced by the microcapsules is filtered and washed, and then dried by a method such as natural drying, powder mist drying, and freeze drying to obtain powdery microcapsules, that is, microcapsule toner. Be done.

An experimental example by this method will be shown. Due to the use of photosensitizers, the following experiments were conducted in a dark room under safe light.

A photoinitiator and a sensitizing dye for initiating a polymerization reaction in the visible light range were mixed with an acrylate monomer which is a photopolymerizable compound to prepare 30 g of an oil-soluble solution.
In this solution, 5 g of magnetic ferrite with a particle size of about 3 microns
And mix with a homogenizer at 6000 rpm for 5
After stirring for minutes, a dispersion liquid in which ferrite was dispersed in an oil-soluble liquid was obtained.

A melamine-formaldehyde prepolymer was used as the reactant. That is, 5 g of powdered melamine and 20 ml of 35% formaldehyde solution were dissolved in water at pH 9.0 to obtain an aqueous solution of a reactant.

The protective colloid aqueous solution was obtained by dissolving 2 g of gelatin in 200 ml of pure water.

The emulsification was carried out by stirring with a homogenizer at 5000 rpm for 5 minutes. After adding the aqueous solution of the reactant to the s / o / w emulsion thus obtained,
Adjust to 6.0, keep temperature at 60 degrees, 5 at 100 rpm
I stirred the time. This liquid was freeze-dried by-
When frozen at 40 ° C. and placed under a vacuum of 0.05 Torr for 12 hours, dried microcapsules, that is, microcapsule toners were obtained.

Next, a second embodiment of the present invention will be described with reference to FIG. This example is a method of mixing a reactant with an oil phase which is a dispersed phase of an s / w / o emulsion.

As the oil-soluble substance and protective colloid,
The same as the first embodiment can be used. Reactants include acrylic acid ester, methacrylic acid ester, vinyl acetate, styrene / divinylbenzene, and the like. The magnetic material is dispersed in the oil-soluble substance, and the reactant is further mixed. This oil-soluble substance is emulsified in a protective colloid aqueous solution to form an s / o / w emulsion. When the temperature and pH of this emulsion were adjusted and stirred, a wall material was produced from the oil phase, which is the dispersed phase of the emulsion, and the wall material encapsulated the oil-soluble substance in which the magnetic particles were dispersed. Generates microcapsules. After that, the microcapsule toner is prepared by the same process as in the first embodiment.

Although the steps of adding the reactant are different between the first embodiment and the second embodiment, s
/ O / w emulsion and in-situ polymerization method are used.

Further, the present invention using the s / o / w emulsion and the interfacial polymerization method can be carried out by changing the method as follows. That is, an oil-soluble Reactant A is mixed with a dispersed phase (oil-soluble substance) and a water-soluble Reactant B is mixed with a continuous phase (protective colloid aqueous solution), respectively, and then an s / o / w emulsion is formed, and You may generate a capsule. In this case, the Reactant A and the Reactant B react with each other to generate a resin that becomes a wall material. This method is called an interfacial polymerization method, and as the resin of the wall material to be produced, polyamide, polyurethane, polyester, polyurea, polycarbonate, etc. can be used.

Next, the image forming apparatus of the present invention will be described with reference to FIG.

In FIG. 4, inside the image forming apparatus M,
An exposure unit 10, a microcapsule toner application unit 20,
A microcapsule toner holding member 44, a transfer roller 45, a heat roller 42, and a cleaning unit 30 are provided.

The holding member 44 holds and conveys the photosensitive microcapsule toner (hereinafter sometimes simply referred to as toner) and has a diameter of 30 mm to 200 m.
Length of about m (length in the direction perpendicular to the paper surface in FIG. 1) 32
It has a cylindrical shape of 0 mm. Further, this holding member 44
Is composed of an outer sleeve member 47 and an inner magnetic pole 46. The sleeve member 47 can be rotated by a drive device (not shown).

The material of the sleeve member 47 is preferably non-magnetic and has high mechanical strength, and aluminum and non-magnetic stainless steel are preferable. However, the surface of the sleeve member 47 may be bonded or coated with ceramics, resin, or the like in order to improve wear resistance and impart releasability.

The magnetic pole 46 is for generating a magnetic flux on the surface of the sleeve member 47, and is provided at least inside the sleeve member 47 and at a position facing the transfer roller 45.

The power source 28 is connected to the metal portion of the holding member 44.

The exposure unit 10 is provided for forming a chemical latent image according to image information on the microcapsule toner held by the holding member 44, and the exposure lamp 1
1, a document table glass 15, a document cover 13, a filter 14 for adjusting the color tone of an image, and a light blocking plate 19.

The microcapsule toner applying section 20 is provided for applying toner to the surface of the holding member 44 by electrostatic force, and stores the toner in the toner case 21.
A toner agitator 23, a toner carrier 25 for carrying toner, a toner supplier 24 for supplying toner to the toner carrier 25, and the stored microcapsule toner 22.

The microcapsule toner 22 is placed between the toner carrier 25 and the holding member 44 by the power source 28 connected to the holding member 44.
An electric field for moving the electric field from the holding member 44 to the holding member 44 is formed.

The transfer roller 45 works in conjunction with the holding member 44 to pressurize the microcapsule toner located between the transfer roller 45 and the holding member 44, and flow out from the microcapsules destroyed due to its weak mechanical strength. Is provided for holding the oil-soluble liquid which has a diameter of 30 to 150
The roller is made of metal and has a length of 320 mm and a length of 320 mm. However, the surface of the transfer roller may be adhered or coated with a resin or the like for easily holding the oil-soluble liquid.

The cleaning unit 3 is located close to the holding member 44.
0 is installed, and the cleaning blade 31 which is a constituent member of the cleaning unit 30 is in contact with the holding member 44.

Below the transfer roller 45, there is provided a heat roller 42 containing a heat source such as a halogen lamp or a resistor. Further, the image receiving paper 52 is supplied between the transfer roller 45 and the heat roller 42.

The microcapsule toner 22 used in the image forming apparatus M is a powder obtained by drying the microcapsule 1 shown in FIG. At least the particles of the magnetic material and the photosensitive material are enclosed by the outer wall of the resin. However, in order to improve the electrical or physical properties required for general toners, specifically, the chargeability and fluidity, fine powder of an organic or inorganic substance is externally added to the outer wall of the microcapsule. It may have been done.

Next, the operation of this device will be described.
When a start switch (not shown) is turned on, the holding member 44
The sleeve member 47 starts rotating in the direction of the arrow in the figure.

In the microcapsule toner applying section 20, the toner is charged and carried on the carrier 25 by the rotation of the agitator 23 and the feeder 24. The carried toner is subjected to electrostatic attraction in the direction of the holding member 44 due to the electric field formed between the holding member 44 and the carrier 25. As a result, the toner moves toward the holding member 44,
It is attached to the holding member 44 by electrostatic force.

The holding member 44 further rotates, and the microcapsule toner is conveyed to the lower portion 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 passes through the filter 14 for adjusting the color tone of the image and is imaged on the surface of the microcapsule toner applied to the holding member 44.

The exposed microcapsule toner is cured because the photosensitive substance inside the capsule undergoes a polymerization reaction depending on the degree of the exposure energy.

Further, the holding member 44 rotates, and the microcapsule toner is conveyed toward the transfer roller 45. Here, the microcapsule toner is sandwiched between the holding member 44 and the transfer roller 45 and pressed. At this time, the magnetic pole 46 provided inside the sleeve member 47 of the holding member 44 causes the sleeve member 47 of the holding member 44 to move.
Magnetic flux is generated in at least a portion of the surface of the sheet facing the transfer roller 45.

Of the pressurized microcapsule toner, the capsules cured by the exposure are not destroyed, but the capsules not exposed are destroyed. The encapsulated photosensitive substance flows out from the destroyed microcapsules. At this time, since the toner and the transfer roller 45 are in contact with each other, at least a part of the photosensitive substance is transferred to the transfer roller 45. Here, the magnetic particles contained in the destroyed microcapsules are retained on the surface of the sleeve member 47 by the magnetic force and do not move to the transfer roller 45.

For the same reason, the microcapsule toner that has been cured and not destroyed is retained on the surface of the sleeve member 47 and is transferred to the transfer roller 45.
Is not transferred to.

In this way, only the photosensitive substance necessary for forming the image is attached to the surface of the transfer roller 45, and the hardened capsule toner and the like unnecessary for the image are not attached.

The holding member 44 further rotates, and the portion coated with the microcapsule toner is conveyed to the cleaning unit 30. The blades 31 of the cleaning unit contact the unnecessary undestructed microcapsule toner adhering to the holding member 44 and the magnetic particles of the destroyed microcapsule toner, and these are removed.

The image receiving paper 52, which is plain paper, is the paper feed cassette 5.
1 and is sent between the transfer roller 45 and the heat roller 42.

The image receiving paper 52 is heated by the heat roller 42.
When the transfer roller 45 is heated, the transfer roller 45
The photosensitive material including the pigment and the like attached to the sheet permeates the image receiving paper 52 and is transferred. Image receiving paper 5 on which an image is formed in this way
2 is discharged to the output tray 54.

[0060]

As is apparent from the above description, according to the method for producing microcapsules of the present invention, photosensitive microcapsules containing magnetic particles can be easily produced.

Further, according to the image forming apparatus of the present invention, the toner formed on the image receiving paper does not originally contain unnecessary toner. Therefore, a high quality image is formed.

[Brief description of drawings]

FIG. 1 is a view showing a cross section of a microcapsule of the present invention.

FIG. 2 is a process drawing for explaining the first embodiment of the method for producing microcapsules of the present invention.

FIG. 3 is a process drawing explaining a second embodiment of the method for producing microcapsules of the present invention.

FIG. 4 is a schematic configuration diagram of an image forming apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microcapsule 2 Magnetic substance 3 Oil-soluble substance 4 Outer wall 10 Exposure part 20 Microcapsule toner coating device 22 Microcapsule toner 30 Cleaning part 42 Heat roller 44 Holding member 45 Transfer member 46 Magnetic pole 47 Sleeve member 52 Image receiving paper

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03G 9/083 9/08 G03G 9/08 394

Claims (2)

[Claims] 1. A method for producing microcapsules containing at least a magnetic substance and a photosensitive substance, wherein a dispersion liquid in which magnetic substance particles are surrounded by an oil-soluble substance is emulsified in a water-soluble continuous phase. A method for producing microcapsules, which comprises using a so-called s / o / w complex emulsion. 2. A microcapsule toner containing at least a magnetic substance and a photosensitive substance is used, and a pressurizing means for causing the photosensitive substance to flow out and a holding means for supplying the microcapsule toner to the pressurizing means. An image forming apparatus having the image forming apparatus, wherein a magnetic pole for holding the magnetic body is provided in at least a part of the holding unit.