JPH0271277A - toner for electrostatic photography - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a new type of electrostatographic toner.

That is, the present invention relates to an electrostatographic toner that develops different colors depending on the heat treatment temperature.

[Prior art]

Conventionally, many patent applications have been filed regarding methods for forming two-color images, including Japanese Patent Application Laid-Open Nos. 543,537 and 55.
As disclosed in -65963 and many other patents, a typical method is to use a photoreceptor in which two types of photoconductor layers having different wavelength responses are laminated, and to use developers of different colors and opposite polarities.

Alternatively, as introduced in JP-A-56-127774, a toner containing a coloring pigment, a leuco dye, and a color developer is formed, and a color-changing or color-erasing material such as diethylene glycol is directly applied to the area where the color is to be changed or erased. A method has also been proposed.

However, since these systems use two types of agents, they have the disadvantage that edge effects occur, the agents mix, and the amount of charge decreases, resulting in a decrease in image density. Furthermore, in the method using leuco-based materials, it is necessary to prepare or prepare and apply a color changing or decoloring agent when necessary. These discoloring or decoloring agents are unstable to heat, and the discolored or decolored areas may return to their original color.

On the other hand, in terms of color copying, many models such as full-color copying and twin-color copying are released by various manufacturers, and although two or more tones can be obtained with one copy, some have two or more built-in developing units. , mechanically complex. And the cost is quite high even to cost 1. Furthermore, monochrome copying has many drawbacks, such as the hassle of replacing the developing unit every time a color copy is made, and clothes get stained.

In addition, JP-A-62-] and 41.63 disclose that [a desensitizer that has a decolorizing effect on color development is used, and when heated, the color of the 1-ner disappears due to the action of this desensitizer. toner. 2,
'' and ``If you mix another coloring agent into this toner, you can create different colors before and after erasing.''
It suggests that. However, since an extra desensitizing agent (hereinafter referred to as a bleaching agent) that has a color erasing effect is added, the cost is 1-2, and the melting point of the bleaching agent is generally low (around 50'C). ), it has poor storage stability, especially heat resistance, and it has various problems such as melting and fading or discoloration during transportation or during summer.

〔the purpose〕

The purpose of the present invention is to form a two-color image using one toner, and to use colorant A and colorant B together, but without using a decoloring agent, and to make a difference by simply selecting a heat treatment temperature. An object of the present invention is to provide an electrostatic photographic toner that can express different colors.

〔composition〕

The present invention is characterized in that the coloring agent A irreversibly develops, changes color, or disappears when heated to a specific temperature, and the color tone of the coloring agent A that is not affected by the color at least at the specific temperature is different. The electrostatic latent image is developed using only one type of toner containing colorant B of a certain color tone, and fixed by heating to obtain a one-color image, and then only the desired part of the image is heated to the above-mentioned specific temperature or higher. A method for forming a two-color image by changing only the desired area to a different tone by coloring, changing or decolorizing the coloring agent A only in the desired area, and use for carrying out the method. Regarding the toner used.

As a result of repeated research on decolorizing Colorant A without using a decolorizing agent, the inventor found that the leuco dye and the color developer react with each other when heated to form a dye. The present invention was achieved by discovering that it decomposes and loses color when the temperature exceeds a certain temperature. This decomposition and decoloring phenomenon is probably caused by the decomposition of the color developer.

That is, the present invention provides: (1) irreversible color development by heating to a specific temperature;
Coloring agent A that changes color or disappears; (2) Coloring agent B that is not affected by color at least at the specific temperature and has a different color tone from the color tone when coloring the city-registered colorant.
and (3) an electrostatic photographic toner that is characterized by being made of a binder resin and capable of developing different colors depending on the heat treatment temperature.

Preferred embodiments of the toner of the present invention are mainly the following three.
Classified into forms (i), (ii) and (iii): (i) the binder resin (3) is a thermoplastic resin particle;
A structure in which a thin layer of colorant B (2) is coated on the surface of the thermoplastic resin particles, and a thin layer of colorant A (1) is further coated on the outer surface of the thin layer of colorant B. Toner that is. 2. (See Figure 1); (i]) Binder resin (3)
are thermoplastic resin particles, the colorant B (2) is dispersed in the thermoplastic resin particles (3), and the colorant A ( 1
) (see Figure 2); and (iii) the binder resin (3) is a thermoplastic resin;
The colorant A (1) is a leuco dye (1') and a color developer (1).
''), the leuco dye (1') and the colorant B (2) are first dispersed in the thermoplastic resin (3) by melt-kneading, and the leuco dye (1') and the colorant B are contained. A toner having a granular structure obtained by further mixing a thermoplastic resin and the color developer (see FIG. 3).

The present invention provides that the colorant A has the property of (1) developing color by reacting the leuco dye and the color developer when heated; (2)
When the colorant that has developed color due to the reaction in (1) is heated to a higher temperature, colorant A gradually begins to decompose within a certain temperature range, causing color change, and then finally disappears at a certain temperature. This skillfully utilizes the property of coloring. The phenomenon (2) above is probably caused by the decomposition of the color developer.

The color developer used in the present invention has a decomposition point at which it decomposes in a high-temperature atmosphere, and when the decomposition point is exceeded, the color developer loses its color developing ability. Therefore, the fixing area for normal copying (160 to 190℃
), the temperature is below the decomposition point, so a variety of leuco dye colors can be obtained. However, if the fixing area is set higher than the above-mentioned area (above the decomposition point), the color developer undergoes thermal decomposition and loses its color developing function.

As shown in Figure 4, colorant A is the color world of colorant B because the leuco dye and color developer do not develop color at temperatures below (a), but at temperatures of (b). When heated to a temperature of 1, the world becomes an intermediate color between colorant A and colorant B, and when heated to temperature (c), the world becomes a world of colorant A. Such discolored areas can be used to form two-color images.

Also, as shown in Figure 4, when colorant A is heated from (d) to (e), its color gradually disappears, and at temperature (f), it completely decomposes and loses its color. It can also be used to form two-color images. At present, the latter method is preferable because a much more stable two-color image can be obtained from the viewpoint of the color change temperature range.

The usual fixing temperature used in this case is preferably 150 to 190°C on the low temperature side (coloring temperature), preferably 170 to 18°C.
0℃ is good. Also, the high temperature side (discoloration to discoloration temperature) is 200~
250°C or a similar amount of heat is preferable. Preferably 2
20-230°C is good.

If the colorant A is a dark color and the colorant B is a light color, the power to hide the color of the colorant B when coloring agent A develops is great. In particular, when black is used as the colorant A, its hiding power is maximum and it is most advantageous.

In the present invention, leuco dyes that can constitute the coloring agent A include, but are not limited to, those that develop a black color such as triphenylmethane series, fluoran derivatives, leuco auramine derivatives, and spiropyran series. isn't it.

Specific examples of leuco dye groups are as follows.

3.3-bis(p-dimethylaminophenyl)-phthalide, 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(p- dimethylaminophenyl)-6-dibutylaminophenyl, 3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6- Chlorfluorane, 3-dimethylamino-5,7-dimethylfluorane, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane.

2- (N-(3'-trifluoromethylphenyl)
Aminoco-6-dinithylaminofluorane, 2-(3,
6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam], 3-diethylamino-6-methyl-7-(mrostylanilino)fluoran, triclodiethylamino(0-chloroanilino)fluoran, 3-dibutylamino- 7-(o-chloroanilino)fluorane, 3-N-methyl-N-amylamino-6nylinofluorane, methyl-7-a3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(N,N-diethylamino)-5-methyldibenzylamino)fluoran, benzoylleucomethylene blue (N,N-6'-chloro-87-med) xy-benzoindolino-pyrillospiran, 6'-bromo-3'-methoxy-benzoindolino-pyrylospiran, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy 5'-Chlorphenyl)phthalide, 3-(2'-hydroxy-4'l)-3-(2'-methoxy-5'lide, diethylaminophenynitrophenyl)phthalide, 3-(2'-hydroxy-4'-diethylamino) phenyl)-3-(2'-methoxy-57-methylphenyl)
Phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'-methylphenyl)phthalide, 3-morpholino-7-(N-propyl- trifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-(N-benzyltrifluoromethylanilino)fluorane, 3-pyrrolidino-7- (di-P-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(αethylamino)fluorane, phenyl 3-(N-ethyl-p-toluidino)-7ethylamino)fluorane, (α-phenyl 3-diethylamino-7-(o-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran, diethylamino-7-piperidinofluorane, 2-chloro-3- (N-methyltoluidino)-7-(p
-n-butylanilino)fluorane, 3-(N-benzyl-N-cyclohexylamino)-5
.

6-penzo 7-α-naphthylamino-41-bromofluorane, and as a color developer, N,N'-di(3-chlorophenyl)thiourea. N,N'-diphenylthiourea, N-
p-Ethyl-N'-phenylthiourea, N-P-butylphenyl-N'-phenylthiourea, N,N'-P
-trifluoromethylthiourea, N,N'-di-m-methylphenylthiourea, etc., but are not limited thereto.

Furthermore, as colorant B, any colorant that is not affected by the temperature range in which the color change of colorant A is utilized and has a color that can be distinguished from colorant A can be used.
Typical examples include (red pigments) red pigments, cadmium red, reseal red, lake red, permahon 1-red, watching red,
Pyrazole Red, Rhodamine Lake, Solvent Red, Disbird's Red, Butt Red, Modern Red (blue pigment) Cobalt Blue, Alkali Blue Lake, Victoria Blue Lake, Phthalocyanine Blue First Sky Blue, Industhrene Blue (yellow pigment) Yellow lead, Examples include cadmium dirho, yellow iron oxide, mineral first yellow, nickel titanium yellow, Hansa yellow, quinoline yellow lake, permanent yellow (green pigment), chromium green, chromium oxide, pigment green, and malachite green lake.

Furthermore, the binder resin used in the present invention is not particularly limited;
Polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, Styrene-maleic acid copolymer, styrene-acrylic ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-
octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylate ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate) styrenic resins (including styrene or styrene substituted products) such as styrene-α-methyl chloroacrylate copolymers, styrene-acrylonitrile-acrylic acid ester copolymers, etc. (homopolymer or copolymer), vinyl chloride resin, rosin-modified maleic acid resin.

Examples include phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral, and the like.

When using the binder resin as described above as core particles, the binder resin is formed into particles by granulation polymerization, and suspension polymerization is preferably used for such granulation polymerization. .

In such a suspension polymerization method, a colorant and other toner components are added as necessary to a polymerization composition consisting of a monomer, a polymerization initiator, a suspension stabilizer, etc., and then polymerization is carried out. The desired nuclear particles can be obtained by substantially the same steps. In the suspension polymerization method, stirring of the suspension system is an important element, and the conditions thereof affect the particle size of the polymer particles and the stability of polymerization.

Depending on the viscosity, interfacial tension, etc. of the polymer composition, the particle size is 1 to 5.
Shear stress 103 to obtain 0 micron polymer particles
Stirring at ~106 dynes/cm2 is sufficient.

Examples of the monomers that can be used in the production of the core particles constituting the toner of the present invention include styrene,
0-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, P-ethylstyrene,
2,4-dimethylstyrene, p-n-butylstyrene,
p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-phenyl styrene,
Preferred examples include styrene monomers such as p-chlorostyrene and 3,4-dichlorostyrene. In addition, for example, ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene;
Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate; methyl acrylate, ethyl acrylate, acrylic acid n -butyl, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate,
lauryl acrylate, 2-ethylhexyl acrylate,
stearyl acrylate, 2-chloroethyl acrylate,
Phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, α-Methylene aliphatic monocarboxylic acid esters such as lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; acrylonitrile, methacrylic acid Acrylic acid or methacrylic acid derivatives such as 1-lyl and acrylamide; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; Vinyl ketones such as vinyl carbazole, vinyl hexyl ketone, and methyl isopropenyl ketone. Class; N-vinylpyrrole, N-
Examples include N-vinyl compounds such as vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; vinylnaphthalenes; and others. These monomers can be used alone or in combination.

(Hereinafter, blank spaces) For the polymerization of the vinyl monomers described above, a polymerization initiator is usually used in an amount of 0.5 to 10% by weight based on the polymerizable monomer. Specific examples of typical polymerization initiators include:
For example, acetylcyclohexylsulfonyl peroxide, isodibutyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, 2,4-dichlorobenzoyl peroxide, t-butyl peroxypivalate, 3 ，
5.5-trimethylhexanonyl peroxide, octanoyl peroxide, decanonyl peroxide,
Lauroyl peroxide, stearoyl peroxide, propionyl peroxide, succinic acid peroxide, acetyl peroxide, t-butyl peroxy-2-ethylhexanoate, benzoyl peroxide, parachlorobenzoyl peroxide, t-butyl peroxide Isobutyrate, t-butyl peroxymaleic acid, t-butyl peroxylaurate, cyclohexanone peroxide, t-butyl peroxyisopropyl carbonate, 2,5-dimethyl 2,5-dibenzoyl peroxyhexane, t- Butylperoxyacetate, t-butylperoxybenzoate-1-, diisobutylciba-oxyphthalate, methyl ethyl ketone peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, t-butylcumyl peroxide, t
-butyl hydroperoxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t-butyl peroxyhexane, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, pinane hydroperoxide, 2 , 5-dimethylhexane-2,5-dihydroperoxide, peroxide-based initiators such as cumene hydroperoxide, 2,2-noazobisisobutyronitrile, 1,1'azobis(cyclohexane-1-carbonitrile) , 2.2'-azobis-4-methoxy-2,4-dimethylvalerodi-1-lyl,
Examples include azo initiators such as 2,2'-azobis-2,4-dimethylvaleronitrile.

In addition, suspension stabilizers are generally classified into water-soluble polymer substances and fine powders of poorly soluble inorganic compounds, and the former include gelatin, starch, polyvinyl alcohol, and others.
The latter include sparingly soluble salts such as barium sulfate, calcium sulfate, barium carbonate, calcium carbonate, and calcium phosphate;
Includes inorganic polymer substances such as talc, clay, silicic acid, diatomaceous earth, metal oxides, and other powders. In addition, when the polymer composition contains an ionic substance, for example, a cationic substance or anionic substance such as a nitrogen-containing polymerizable monomer or poorly water-soluble amines, when dispersed in water, the dispersed particles are In the case of being charged to either positive or negative polarity, an ionic dispersant that is charged to the other polarity when dispersed in water, such as negatively charged colloidal silica,
Positively charged aluminum oxide or the like can be effectively used as a suspension stabilizer.

Next, three representative forms (i), (ii) and (
The manufacturing method of each of the toners (ijj, ) will be described in detail below.

(i) First, a binder resin (thermoplastic resin particles) with an average particle size of 5 to 20 μm and colorant B are mixed by applying mechanical strain to form a thin layer of colorant B on the resin core particles. form. Next, the colorant A is further coated on top of it to form a layered structure as shown in FIG.

Mixing by mechanical strain force ultimately results in an average particle size of 5 to 30μ.
, preferably in the range of 15 to 25μ.

There are no particular restrictions on the method of granulating the binder resin particles as core particles with an average particle size of 5 to 20μ, including (a) crushing, classification,
Methods include (b) suspension polymerization, (c) dissolution, precipitation, and (d) spraying.

In addition, the mixing conditions for mixing resin core particles and colorants B and A to form particles with an average particle size of 5 to 30 μm are as follows: The conditions are such that the resin does not fuse and form a large lump, or conversely, the strain force is too large and the resin is not pulverized to become too fine.

The conditions are such that the coloring agent 13 is attached as a thin layer to the surface of the core particle of the binder resin, and the coloring agent A is further attached to the surface of the core particle of the binder resin to form a thin film in the state of primary particles.

As a specific method that satisfies both of these conditions, a mortar is mainly used in the laboratory, and a grinder, a ball mill, a vibration mill, a sand mill, etc., which have the same effect as a mortar, are used industrially. However, with the devices and equipment described above, it takes a long time to obtain the desired granular material. It is preferable to use a mixer that is equipped with a blade, hammer, etc. that gives a blow. Examples of such a mixer include a 71-mizer, an automatic pulverizer, and the like. Preferably, a circulating type and closed system device, such as a hybridizer manufactured by Nara Kikai Co., Ltd., is preferable.

This mixing process produces the effect that colorants B and A are attached to the surface of the binder resin particles and embedded in the state of primary particles because the binder resin particles and the colorant particles are not powders or =24 collides with a dispersion medium such as a wall or a blade, producing a momentary and partially high-pitched sound, and it is thought that a phenomenon similar to a mechanochemical reaction is occurring.

The average particle size of the toner of the present invention thus obtained is 5.
-30μ, preferably 15-25μ; if the particles have a particle size of 15μ or less, the fluidity of the toner becomes poor and problems such as background smearing are likely to occur; As the particle size increases, problems such as poor image sharpness tend to occur.

(ii) Colorant B-containing binder resin particles having an average particle size of 5 to 20 μm are prepared by suspension polymerization of colorant B in the binder resin described above. The thus prepared colorant B-containing binder resin particles and colorant A are mixed by applying mechanical strain to form four layers of colorant A on the colorant B-containing resin particles.
The toner has a structure as shown in FIG. Mixing by mechanical strain is carried out under the same conditions as described above, so that the final average particle size is in the range of 5 to 30 microns, preferably in the range of 15 to 25 microns.

In addition to the method of coating the colorant A by applying mechanical strain, the colorant A may be coated by a dyeing method. That is,
After adding resin particles containing dispersed colorant B through suspension polymerization or melt kneading into a polar solvent with an SP value of 10 to 20,
Heat in the range of 30 to 40°C for 30 minutes to 3 hours.

This heating step is performed in order to heat and swell the surface of the colorant B-containing resin particles in a polar solvent, thereby making it easier to adsorb colorant A.

(iii) First, the colorant B and the leuco dye are incorporated into the binder resin described above by melt mixing, and then a color developer is further mixed and granulated, so that a coloring agent as shown in FIG. 3 is obtained. The final structure of the toner is such that the average particle size is in the range of 5 to 30 microns, preferably in the range of 15 to 25 microns.

In the production of toners having the respective forms (i), (ii), and (iii), colorant B is used in an amount of 5 to 10 parts by weight based on 100 parts by weight of binder resin, and colorant A is used in an amount of 5 to 10 parts by weight based on 100 parts by weight of binder resin. is used in an amount of 10 to 40 parts by weight based on 100 parts by weight of the binder resin. Furthermore, among the colorant A, the leuco dye is used in an amount of 5 to 10 parts by weight per 100 parts by weight of the binder resin, and the color developer is used in an amount of 5 to 10 parts by weight per 100 parts by weight of the binder resin.
It is used in an amount of 30 parts by weight.

In order to form a two-color image using the toner of the present invention,
For example, a color tone converter with a built-in thermal head is added to the paper output section at the rear end of the fuser section of a copying machine, and a color tone converter with a built-in thermal head is added to the paper output section at the rear end of the fuser section of a copying machine. A two-color image can be easily formed by sending signals to.

〔effect〕

1. Unlike conventional color copying machines, there is no need to incorporate two or more developing units (developer or toner), making the copying machine lightweight and compact. Color and mid-color copies can be obtained.

2. Also, since two or more types of developing powder (toner) are not used, toners do not mix with each other, so abnormal images due to contamination are eliminated.

3. There is no need to replace the developing section, so there is no need to stain clothes or hands.

4. The cost is low because no bleaching agent is used, and there is no need to worry about the shelf life of the bleaching agent.

〔Example〕

Next, the present invention will be explained with reference to Examples.

Example 1 Styrene-2-ethylhexyl acrylate-n-butyl methacrylate copolymer was crushed and classified to prepare particles with an average particle size of 15μ, and the content of large particles with a particle size of 25μ or more was reduced to almost 0%. ) was used as a core particle for film formation. 100 parts by weight of the core particles and 5 parts by weight of colorant B (Pigment Red 112) were predispersed for 10 minutes using a Henschel mixer (manufactured by Mitsui Miike) at a low/see blade rotation speed to bind colorant B. It was attached onto the surface of the resin particles. Next, this pre-dispersed powder was put into a hybridizer (manufactured by Nara Kikai) and allowed to stay there for 10 minutes at an internal rotary blade outer peripheral speed of 85 m/sec, and then collected by a collector. The average particle size of the particles thus prepared was 15
．． It was 6μ.

Next, as colorant A, leuco dye (3-N-cyclohexyl-N-methyl-6-methyl-7-anilite fluorane) and color developer (N,N'-di(3-chlorophenyl)thiourea) were used. ) in a weight ratio of 4/1, and 10 parts by weight of this mixture was added to the powder 10 prepared as described above.
0 parts by weight, and after residence in a hybridizer for 10 minutes with the rotational speed of the blades set in the same manner as described above, the toner was recovered to obtain the toner of the present invention.

When this toner was made into a developer and copied using Ricoh's FT-5520, the color tone was black when the fixing temperature was set to 185°C, but when the fixing temperature was set to 210°C and 230°C.
When changed to ℃, sepia color at 210℃, 230℃
It turned red in color.

Example 2 In Example 1, the colorant B Pigment Rerad 112
A toner was obtained in exactly the same manner as in Example 1 except that phthalocyanine blue was used instead of phthalocyanine blue.

This toner was made into a developer and developed using Ricoh's FT-555.
When copying at 0, the color was black when the fusing temperature was set to 185°C, but when the fusing temperature was set to 210°C, the color was black.
When the temperature was changed to 245℃, it turned dark blue at 210℃, 24
The color became sky blue at 5°C.

Example 3 Using the toner obtained in Example 1, FT-5 manufactured by Ricoh
I copied the calendar using 520. At this time, the fixing temperature was 180° C. and the copy color tone was black.

Next, we installed a color changer with a built-in thermal head in the paper output section of the FT-5520, and changed only Sunday and its numbers to 21.
A signal was input to heat it to 5° C., and the black-only copy was passed through the color changer.

Then, only Sunday and its number changed to red, while the rest remained black.

Example 4 Styrene/2-ethylhexyl acrylate/n-butyl methacrylate monomer and colorant B (Pigment Red 112) were suspension-polymerized in an aqueous solution so that the average particle size of the dry product was 15 to 25μ. Separation adjustment was made. When the average particle size was measured, it was 16.5μ (volume). Then, the colorant B-containing particles 100 prepared in this way
Weight parts and colorant A (3-N-cyclohexyl-N-methyl-6-methyl-7-anilite fluorane and N,N'
-di(3-chlorophenyl)thiourea in a weight ratio of 4/
1) was predispersed for 10 minutes using a Henschel mixer (manufactured by Mitsui Miike) with a blade rotation peripheral speed set at 10 m/see, and colorant A was adhered onto the surface of the binder resin particles. . Next, this pre-dispersed powder is put into a hybridizer (manufactured by Nara Kikai) and allowed to stay there for 10 minutes at an internal rotary blade outer peripheral speed of 85 m/secC, and then collected by a collector to obtain the 1- I was nervous.

When this toner was made into a developer and copied using Ricoh's FT-5520, the color tone was black when the fixing temperature was set to 185°C, but when the fixing temperature was set to 210°C and 230°C.
When changed to ℃, sepia color at 210℃, 230℃
It turned red in color.

Example 5 In Example 4, Pigment Red 112 of colorant B
A toner was obtained in exactly the same manner as in Example 4 except that phthalocyanine blue was used instead of phthalocyanine blue.

This toner was made into a developer and developed using Ricoh's FT-555.
When copying at 0, the color was black when the fusing temperature was set to 185°C, but when the fusing temperature was set to 210°C, the color was black.
When the temperature was changed to 245℃, it turned dark blue at 210℃, 24
The color tone became sky blue at 5°C. Example 6 Using the toner obtained in Example 4, FT-5 manufactured by Ricoh
I copied the calendar using 520. At this time, the fixing temperature was 180° C. and the copy color tone was black.

Next, we installed a color changer with a built-in thermal head in the paper output section of the FT-5520, and changed only Sunday and its number to 22.
A signal was input to heat it to 0° C., and the black-only copy was passed through the color changer.

Then, only Sunday and its number changed to red, while the rest remained black.

Example 7 (2) Pigment Red 112 1.5 parts by weight (4) N-N'-di(3-chlorophenyl)thiourea 20 parts by weight (5) Polyvinyl resin
30 parts by weight (1), (2) of the above formulation
), (3), and (5) at 150℃ using a hot roll mill.
After melting and kneading for 30 minutes and lowering the kneading temperature to 110°C, (4) was added and kneaded for 10 minutes. The kneaded product was coarsely pulverized and finely pulverized, and the obtained powder was classified to select 5 to 30 microns, which was used as the toner of the present invention.

Copies were made using this toner with Ricoh FT-5520.

The copy color tone at this time was a clear black.

The fixing temperature at this time was 185°C. When this copy was further heat-treated at 230° C. in a fixing tester, the black tone changed to a clear red tone.

Example 8 A toner of the present invention was obtained in the same manner except that (2) of Example 7 was changed to phthalocyanine blue. When this toner was used for copying with Ricoh's FT-5520, a clear black tone was obtained. The fixing temperature at this time was 183°C. Next, this copy was heat-treated at 230° C. in a fixing tester, and the color changed to a clear bluish tone.

Example 9 A toner of the present invention was produced using the same method except that (4) in Example 7 was changed to N,N'-diphenylthiourea. I got 2. When this toner was used for copying with Ricoh's FT-5520, a clear black tone was obtained. The fixing temperature at this time was 180°C. Next, when this copy image was heated to 215° C. in a fixing tester, it changed to a clear red-brown tone.

Example 10 A toner of the present invention was obtained in the same manner as in Example 7 except that (3) was changed to 2-ortho-chloroanilino-6-diethylaminofluorane. When this toner was used for copying with Ricoh's FT-5520, a clear black tone was obtained. The fixing temperature at this time was 178°C. Next, this copy image was heat-treated at 220° C. in a fixing tester, and the color changed to a clear red color.

Example 11 Example 7 (3) was converted into 2-ortho-chloroanilino-6-
The toner of the present invention was obtained in the same manner except that dinithylaminofluorane was used and (4) was changed to N,N'-diphenylthiourea. Using this toner, Ricoh Togo 55
20, a clear black tone was obtained. The fixing temperature at this time was 180°C. Next, this copy image was heat-treated at 230° C. in a fixing tester, resulting in a clear red-brown tone.

Example 12 100 parts by weight of styrene/2-ethylhexyl acrylate/n-butyl methacrylate-1 to copolymer and 5 parts by weight of colorant B (Pigment Red 112) were melt-kneaded at 150°C for 30 minutes in a heated roll mill. Thereafter, the kneaded material was pulverized through coarse pulverization and pulverization steps, and the resulting powder was classified to select particles of 5 to 30 microns to prepare colorant B-containing resin particles.

Next, the colorant B-containing resin particles lOO prepared in this way
Weight parts and colorant A (3-N-cyclohexyl-N-methyl-6-methyl-7-anilite fluorane and N,N'
-di(3-chlorophenyl)thiourea in a weight ratio of 4/
After putting 20 parts by weight of the mixture of 1) into a polar solvent with an SI) value of 15, it was heated at 40° C. for 1 hour and then suction-dried, followed by a fixation treatment to obtain the toner of the present invention. .

When this toner was made into a developer and copied using Ricoh's FT-5520, the color tone was black when the fixing temperature was set to 180°C, but when the fixing temperature was set to 220°C and 250°C, the color was black.
When changed to ℃, sepia color at 220℃, 250℃
It turned red in color.

Example 13 In Example 12, Pigment Red 11 of colorant B
A toner was obtained in exactly the same manner as in Example 12, except that phthalocyanine blue was used instead of No. 2.

This toner. 2, was made into a developer and similarly manufactured by Ricoh FT5.
When copying with 520, the color was black when the fusing temperature was set to 185°C, but when the fusing temperature was set to 210°C, the color was black.
℃, 245℃, dark blue color at 210℃,
Example 14 The toner obtained in Example 12 was used to obtain a sky blue color tone at 245°C.
I copied the calendar using 5520. At this time, the fixing temperature was 180° C. and the copy color tone was black.

Next, we installed a color changer with a built-in thermal head in the paper output section of the FT-5520, and changed only Sunday and its number to 22.
A signal was input to heat it to 0° C., and the black-only copy was passed through the color changer.

Then, only Sunday and its number changed to red, while the rest remained black.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are explanatory diagrams of the structure of toner of each form of the present invention. FIG. 4 is an explanatory diagram showing the relationship between colorant A and colorant B in terms of color density and temperature. ■600 Colorant A 2. ,, Colorant B500. Binder resin 1. ' , , , Leuco dye 1 '' ＋ ＋
H color developer

Claims (1)

[Scope of Claims] 1. (1) Coloring agent A that irreversibly develops, changes color, or decolors when heated to a specific temperature; (2) Colorant A that is not affected by color at least at the specific temperature; An electrostatic photographic toner capable of developing different colors depending on the heat treatment temperature, characterized by comprising a colorant B having a color tone different from that of the colorant A when developing the color, and (3) a binder resin. 2. The binder resin (3
) are thermoplastic resin particles, a thin layer of colorant B(2) is coated on the surface of said thermoplastic resin particles, and colorant A(1) is further coated on the outer surface of said thin layer of colorant B. 2. The electrostatographic toner according to claim 1, which has a structure in which a thin layer of is coated. 3. The binder resin (3) is a thermoplastic resin particle, the colorant B (2) is dispersed in the thermoplastic resin particle (3), and the thermoplastic resin contains the colorant B. 2. The electrostatic photographic toner according to claim 1, which has a structure in which a thin layer of colorant A(1) is coated on the surface of the particles. 4. The binder resin (3) is a thermoplastic resin, and the colorant A (1) is a thermoplastic resin.
) consists of a leuco dye and a color developer, the leuco dye and the colorant B (2) are dispersed in the thermoplastic resin (3) by melt kneading, and the leuco dye and the colorant B are dispersed in the thermoplastic resin (3) by melt kneading. 2. The electrostatic photographic toner according to claim 1, wherein the thermoplastic resin and the color developer are further mixed to form a granular structure.