JP2000314984A - Decolorable toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a decolorable toner capable of efficiently utilizing the energy of irradiated light for decoloring and having reduced saturation by incorporating two specified colorants having a specified interval between the absorption peaks in the visible light region and a specified decolorant. SOLUTION: The photo-decolorable toner consists of a matrix of a resin A, two colorants (dyes) of the formula Z+.A- (I) different from each other in hue and a decolorant of formula II. The colorants have >=20 nm interval between the absorption peaks in the visible light region. In the formula I, Z+ is a cation having absorption in the range from the visible light region to the near infrared region and A- is an anion selected from a boron ion, a halogen ion, a perchlorate ion, PF6-, etc. In the formula II, 1-R8 are each H, alkyl, a cycloaliphatic group, aryl or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a decolorizable toner. More specifically, an electric latent image (electrostatic latent image) is formed using a photoconductive substance, and then the latent image is developed using toner, and if necessary, is formed on an image support such as paper. The present invention relates to a decolorizable toner used in a photographic method or a printing method in which a powder image formed of a toner is transferred and then fixed by heating, pressing or other appropriate fixing method.

[0002]

2. Description of the Related Art Copies and printed materials that are no longer needed or that are incorrectly copied,
It is generally discarded. Such waste is disposed of by incineration or landfill.

On the other hand, paper recycling (recycled paper) has attracted attention in terms of nature protection and reduction of the problem of urban garbage. In fact, it is not very popular. Therefore, if it is possible to easily erase the characters and images of the copy and the printed matter as described above, the paper can be recycled in an office or the like, and the above-mentioned problems are reduced.

[0004] In order to erase and recycle characters and images of copied and printed materials, it is necessary to erase characters and images easily, quickly and safely. In this method, a dye having a function of decoloring by irradiation with near-infrared light of a certain wavelength (Japanese Patent Laid-Open No. 4-362935) is contained in a binder resin for decolorization of an electrostatic latent image. Toner (JP-A-5-11
9520, etc.) and related techniques using the decolorizable toner.

[0005] Since the color of the colorant of the decolorizable toner becomes colorless due to a photochemical reaction, the copied or printed paper can be recycled. This photochemical reaction is
Since the reaction is caused by the light energy absorbed by the colorant, a photochemical reaction cannot be sufficiently caused by light having a wavelength other than the wavelength at which the colorant has an absorption peak. Therefore, not all of the energy of light emitted for decolorization is efficiently used for the decolorization reaction. That is, the energy of the light emitted for decoloring is wasteful.

[0006] Originally, the decolorizable toner is a product that contributes to protection of forest resources and environmental protection by reducing the amount of paper used. desirable.

[0007] The decolorizable toner is a color other than black, but is used for documents, mainly for documents, like general black toner. In the case of such a document centered on characters, a vivid color copy is difficult to read because fine characters and the like are dazzling. Therefore, the color of the decolorizable toner is preferably as low as possible in color. Ideally, a color close to black is preferable.

[0008] However, the colorants that become colorless by the photochemical reaction as described above are limited to compounds having a specific chemical structure. Most colorants used in black toner, such as carbon, do not undergo such a chemical reaction.

[0009]

Means for Solving the Problems The present invention has been made to solve the above problems, in the decolorizable toner by an optical, general formula ^{(I): Z + · A} - (I) ( In the formula, Z ⁺ is a cation having absorption from the visible light region to the near infrared light region, A ⁻ is a boron ion, a halogen ion, a perchlorate ion, PF ₆ ⁻ , BF ₄ ⁻ , SbF ₆ ⁻ , and OH ^−. and R-SO ₃ ^- anion selected from, wherein, R is an alkyl group, an aryl group, an aralkyl group, a substituted alkyl group,
(A substituted aryl group or a substituted aralkyl group) represented by the following formula (II):

[0010]

Embedded image

(Wherein, R ^{1 to} R ⁸ each independently represent a hydrogen atom, an alkyl group, an alicyclic group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a silyl group, a heterocyclic group, a substituted alkyl group, Group, substituted alicyclic group, substituted aryl group,
A aralkyl group, a substituted alkenyl group, a substituted alkynyl group or a substituted silyl group), and the two colorants are separated by 20 nm or more in the absorption peak in the visible light region. A color erasable toner (Claim 1), a toner erasable by light, comprising three kinds of colorants having different hues belonging to the colorant represented by the general formula (I) and the colorant represented by the general formula (I)
A decolorizable toner containing the decoloring agent represented by I), wherein the peak tops of the absorption peaks in the visible light region of each of the three colorants are separated from each other by 20 nm or more (claim 2); One of the three colorants belonging to the colorant represented by the formula (I) has a hue in the Munsell color specification of any of G, BG, B, and PB, and one type has P, RP, and R. One of the remaining is YR,
3. The decolorizable toner according to claim 2, which is either Y or GY, wherein one of the three colorants belonging to the colorant represented by the general formula (I) has a wavelength of 400 to 500 nm. It has a peak top of the absorption peak, and one kind is 500 to 570
The decolorizable toner according to claim 2 or 3, wherein the toner has a peak top of an absorption peak at nm and one of the residues has a peak top of an absorption peak at 570 to 700 nm (claim 4).
And the decolorizable toner according to claim 1, wherein the saturation (C) in the Munsell color specification is 12 or less.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the toner capable of being decolorized by light according to the present invention include a matrix composed of resin A, a decolorizable toner composed of a colorant (dye) and a decolorant.

[0013] As the coloring agent, the general formula ^{(I): Z + + A} - in (I) (wherein the cation Z ⁺ is having an absorption in the near infrared region from the visible light region, A ^- boron ion, halogen ion, perchlorate _{^{ion, PF 6 -, BF 4 -}} , SbF 6 -, OH - and R-SO ₃ ^- anion selected from, wherein, R is an alkyl group, an aryl group, an aralkyl group, a substituted Alkyl group,
A substituted aryl group or a substituted aralkyl group) and two or three colorants having different hues belonging to the colorant, and the peak of the absorption peak in the visible light region of the two or three colorants. Top 20nm each
It is necessary to be at least separated. As described above, since two or three kinds of colorants having different hues in which the peak tops of the absorption peaks are separated by 20 nm or more are used,
The color tone becomes dark. In particular, by mixing red, blue, and yellow colors, an achromatic color, that is, close to black, can be obtained, and a color such as a fine character can be easily read. Further, it can absorb a wide wavelength range of light irradiated for decoloring and can be used for a decoloring reaction.

As the two or three colorants having different hues, the hues in the Munsell color specification are G, BG, B, P
B, any of P, RP, R, YR,
It is preferable to use a combination of two or three selected from any of Y and GY from the viewpoint that the color can be made close to black.
m, each having a peak top of the absorption peak separately in any of the ranges of 500 to 570 nm and 570 to 700 nm, and the peaks separated by 20 nm or more are preferable.

The coloring agent represented by the general formula (I) includes, for example, the general formula (III):

[0016]

Embedded image

(Wherein, Z ⁺ is a cation having absorption in the visible light region to the near infrared light region, R ⁹ , R ¹⁰ , R ¹¹ and R ¹²
Are each independently a hydrogen atom, an alkyl group, an alicyclic group,
Aryl group, aralkyl group, alkenyl group, alkynyl group, silyl group, heterocyclic group, substituted alkyl group, substituted alicyclic group, substituted aryl group, substituted aralkyl group, substituted alkenyl group, substituted alkynyl group or substituted silyl group Show)
In cationic colorant represented (cationic dye) or the general formula ^{(IV): Z + · E} - (IV) ( wherein, Z ⁺ is a cation having an absorption in the near infrared region from the visible light region, E ^- is a halogen ion, a perchlorate ion,
PF ₆ ⁻ , SbF ₆ ⁻ , BF ₄ ⁻ , OH ⁻ or a sulfonate ion (R—SO ₃ ⁻ , wherein R is an alkyl group, an aryl group, an aralkyl group, a substituted alkyl group, a substituted aryl group or a substituted aralkyl group; A cationic colorant (cationic dye) represented by) is given as a typical example.

Preferred examples of Z ⁺ in the general formula (III) include, for example, cyanine, triarylmethane, aminium, diimmonium, thiazine, xanthene, thiazine, oxazine, diallylmethane, triallylmethane, styryl, Examples include cations contained in pyrylium and thiopyrylium-based cationic dyes. Representative examples of such cationic dyes include, for example, those described in Table 1-1 to Table 1-7.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

[Table 5]

[0024]

[Table 6]

[0025]

[Table 7]

In Tables 1-1 to 1-7, M
e: methyl group, Et: ethyl group, n-Bu: n-butyl group, n-Hex: n-hexyl group, n-Oct: n-octyl group, Ar: aryl group, Ph: phenyl group, To
l: tolyl group, Anisyl: anisyl group, OMe: methoxy group.

Further, R ⁹ and R in the general formula (III)
Specific examples of ¹⁰ , R ¹¹ and R ¹² include a hydrogen atom, an alkyl group, an alicyclic group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a silyl group, a heterocyclic group and a substituted alkyl group as described above. , A substituted alicyclic group, a substituted aryl group, a substituted aralkyl group, a substituted alkenyl group, a substituted alkynyl group, and a substituted silyl group. Of these, at least one of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² It is preferable that one is an alkyl group in order to promote the decolorization reaction.

Specific examples of the alkyl group include, for example, n-butyl group, n-pentyl group, n-hexyl group and n-hexyl group.
An alkyl group having 1 to 12 carbon atoms, such as a heptyl group, an n-octyl group, or an n-dodecyl group;

Specific examples of the alicyclic group include C5-C6 alicyclic groups such as a cyclohexyl group and a cyclohexenyl group.

Further, specific examples of the aryl group include, for example, phenyl group and naphthyl group; specific examples of the aralkyl group include, for example, benzyl group; specific examples of the alkenyl group include, for example, vinyl group, allyl group, and the like. Specific examples of silyl groups include, for example, triphenylsilyl group, dimethylphenylsilyl group, dibutylphenylsilyl group, trimethylsilyl group and the like; specific examples of heterocyclic groups include piperidyl group, thienyl group,
Specific examples of the substituted alkyl group include, for example, methoxymethyl group and methoxyethyl group; specific examples of the substituted aryl group include, for example, anisyl group, ethoxyphenyl group, tolyl group, tolyl group, t-butylphenyl Group, fluorophenyl group, chlorophenyl group, diethylaminophenyl group, xylyl group and the like.

An anion in the general formula (III):

[0032]

Embedded image

Specific examples of the above include, for example, methyl triphenyl boron ion, ethyl triphenyl boron ion, n-butyl triphenyl boron ion, n-octyl triphenyl boron ion, n-dodecyl triphenyl boron ion, methyl tri-p- Tolyl boron ion, ethyl tri-p-tolyl boron ion, n-butyl tri-p-tolyl boron ion, n-octyl tri-p
-Tolyl boron ion, n-dodecyl tri-p-tolyl boron ion, methyl trianisyl boron ion, ethyl trianisyl boron ion, n-butyl trianisyl boron ion, n-octyl trianisyl boron ion, n-dodecyl trianisyl boron ion Dimethyldiphenylboron ion, diethyldiphenylboron ion, di-n-butyldiphenylboron ion, din-octyldiphenylboron ion, din-dodecyldiphenylboron ion, dimethyldi-p-tolylboron ion, diethyldi-p-tolylboron ion Di-n-butyldi-p-tolyl boron ion, di-n-octyldi-p
-Tolyl boron ion, di-n-dodecyl di-p-tolyl boron ion, dimethyl dianisyl boron ion, diethyl dianisyl boron ion, di n-butyl dianisyl boron ion, di n-octyl dianisyl boron ion, di n-dodecyl Dianisyl boron ion, tetraphenyl boron ion, tetraanisyl boron ion, tetra-p-tolyl boron ion, triphenyl naphthyl boron ion, tri-p-tolyl naphthyl boron ion, tetrabutyl boron ion, tri n-butyl (tri Phenylsilyl) boron ion, tri-n-butyl (dimethylphenylsilyl) boron ion, n-octyldiphenyl (di-n-butylphenylsilyl) boron ion,
And dimethylphenyl (trimethylsilyl) boron ion.

E in the above general formula (IV)^-Halogen
Fluorine ion, chlorine ion, bromine ion
And iodine ions;
For example, CH_ThreeSO_Three ^-Methyl sulfonate ion such as F
CH_TwoSO_Three ^-, F_TwoCHSO_Three ^-, F_ThreeCSO_Three ^-, ClCH_Two
SO_Three ^-, Cl_TwoCHSO_Three ^-, Cl_ThreeCSO_Three ^-, CH_ThreeOC
H_TwoSO_Three ^-, (CH_Three)_TwoNCH_TwoSO_Three ^-Substituted methyl such as
Sulfonate ion, C ₆H_FiveSO_Three ^-Such as phenylsulfo
Acid ion, CH_ThreeC₆H_FourSO_Three ^-, (CH_Three)_TwoC₆H_ThreeS
O_Three ^-, (CH_Three)_ThreeC₆H_TwoSO_Three ^-, HOC₆H_FourSO_Three ^-,
(HO)_TwoC₆H_ThreeSO_Three ^-, (HO)_ThreeC₆H_TwoSO_Three ^-, CH
_ThreeOC₆H_FourSO_Three ^-, C₆H_FourClSO_Three ^-, C ₆H_ThreeCl_TwoS
O_Three ^-, C₆H_TwoCl_ThreeSO_Three ^-, C₆HCl_FourSO_Three ^-, C₆Cl
_FiveSO_Three ^-, C₆H_FourFSO_Three ^-, C₆H_ThreeF_TwoSO_Three ^-, C₆H_TwoF
_ThreeSO_Three ^-, C₆HF_FourSO_Three ^-, C₆F_FiveSO_Three ^-, (CH_Three)_Two
NC₆H_FourSO_Three ^-Such as substituted phenylsulfonate ion
Throw.

[0035] Z ⁺ in formula (IV) are those same as Z ⁺ in formula (III) is used particularly without limitation.

Two or three kinds, preferably G and BG, belonging to the colorants represented by the above general formula (I), which have different hues and whose peaks of absorption peaks in the visible light region are separated from each other by 20 nm or more. , B, PB, P, RP, R, YR, Y, GY
Two or three selected from any of the above, more preferably those having an absorption peak peak at 400 to 500 nm, those having an absorption peak at 500 to 570 nm, and those having an absorption peak at 570 to 700 nm. Two or three types selected from those having a peak top are used.

When three types are used, it is desirable that the peak tops are separated from each other on average (about the same).

The proportion of the two or three kinds of colorants used is preferably such that the chroma of the produced toner becomes low. Since the absorptivity differs depending on the coloring agent, those skilled in the art may appropriately select the coloring agent according to the type of the coloring agent.

The amount of the coloring agent used is generally 0.05 parts or more, more preferably 0.3 parts or more, per 100 parts by weight (hereinafter referred to as "parts") of the resin A in order to sufficiently color the resin. Note that the upper limit is 20 parts, and further 7 parts.

Examples of the resin A include homopolymers of styrene such as polystyrene, poly p-chlorostyrene, and polyvinyltoluene and substituted products thereof;
Methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate Copolymer, styrene-octyl methacrylate copolymer, styrene-butyl acrylate-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-hydroxyethyl acrylate copolymer, styrene-acrylate- Styrene- (meth) acrylate-based copolymers such as hydroxyethyl acrylate-based copolymer, styrene-hydroxypropyl acrylate copolymer, styrene-acrylonitrile copolymer, Styrene-acrylonitrile copolymers such as styrene-acryl rubber-acrylonitrile copolymer, styrene-EPDM-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-chlorinated polyethylene-acrylonitrile copolymer, and styrene- p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-vinylmethylether copolymer, styrene-vinylethylether copolymer, styrene -Vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-
Other styrene copolymers such as indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, polyacrylic acid, polymethyl methacrylate, polybutyl methacrylate, polyhydroxymethyl acrylate, poly (Meth) acrylic acid resins represented by hydroxyethyl acrylate, polyhydroxypropyl acrylate, polyhydroxymethyl methacrylate, polyhydroxyethyl methacrylate, polyhydroxypropyl methacrylate, etc .; polyester resins represented by saturated polyesters, unsaturated polyesters, etc. , Ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer such as modified ethylene-vinyl acetate copolymer, polyethylene, olefin resin such as polypropylene, Poxy resin, vinyl chloride resin, silicone resin, fluorine resin, polyamide resin, polyvinyl alcohol resin, polyurethane resin, polyvinyl butyral, rosin, modified rosin, rosin modified phenol formaldehyde resin, phenol formaldehyde resin, phenol resin, acetic acid Examples include vinyl resins, terpene resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes, carnauba waxes, etc., but the present invention is limited to only such examples. is not. These may be used alone or in combination of two or more.

Among the resins A, for example, polyester resins, epoxy resins, (meth) acrylic acid resins, polyamide resins, polyvinyl alcohol resins,
Polyurethane resin, polyacrylonitrile resin, polyvinyl acetate resin, phenol resin, styrene
In the molecule of (meth) acrylate copolymer, styrene-acrylonitrile copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, etc., selected from hydroxyl group, cyano group, carboxyl group and carbonyl group. Such a highly polar resin having at least one type of group exhibits excellent anti-fading properties and can be particularly preferably used.

The resin A is made of 30 parts of the resin A in order to prevent residual color when an image formed using the obtained decolorizable toner is irradiated with visible light to near infrared light. L * a * by a color difference meter in an ethyl acetate solution
b * value at b color coordinate is 20 or less, preferably -20
~ 20, more preferably -5 ~ 20.

The L * value, a * value, and b * value in the present invention were all determined using a 30% ethyl acetate solution of Resin A and a color difference meter "Z- @ 90 C" manufactured by Nippon Denshoku Industries Co., Ltd.
This is a value obtained by transmitted light measurement using “OLOR MEASURING SYSTEM”.

As the L * value increases, the brightness increases, and as the L * value decreases, the brightness decreases. The a * value becomes green as the value increases and becomes red as the value decreases. The b * value becomes yellow as the value increases, becomes colorless as it approaches 0, and becomes blue as the negative value increases.

In the present invention, it is particularly preferable that the b * value is 20 or less. When the b * value is larger than 20, the resin A is colored yellow, and the yellow coloring is obtained. This has an adverse effect on the hue of the image after erasing.

In the present invention, a wax such as a polyolefin wax or a paraffin wax may be added to the resin A, if necessary.

The amount of the wax is 0.1 part or more, preferably 0.5 part or more with respect to 100 parts of the resin A, in order to sufficiently exhibit the effect of the wax, for example, the effect of preventing offset. It is desirable that If the amount of the wax is too large, film formation on a photoreceptor that forms an electric latent image tends to occur.
Preferably, it is 10 parts or less.

The decoloring agent used in the present invention has the general formula (I)
I):

[0049]

Embedded image

(Wherein R ^{1 to} R ⁸ each independently represent a hydrogen atom, an alkyl group, an alicyclic group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a silyl group, a heterocyclic group, a substituted alkyl group , A substituted alicyclic group, a substituted aryl group,
A substituted aralkyl group, a substituted alkenyl group, a substituted alkynyl group or a substituted silyl group).

The alkyl, alicyclic, aryl, aralkyl, alkenyl, alkynyl, alkynyl, silyl, heterocyclic and substituted alkyl groups mentioned as examples of R ^{1 to} R ^{8 in} formula (II) Group, substituted alicyclic group, substituted aryl group,
Specific examples of the substituted aralkyl group, substituted alkenyl group, substituted alkynyl group or substituted silyl group include compounds represented by the general formula (II
The same as the specific example of I) can be mentioned.

Representative examples of the decoloring agent (boron compound) represented by the general formula (II) include, for example, tetramethylammonium methyltriphenylboron, tetramethylammonium n-butyltriphenylboron, tetramethylammonium n-octyl Triphenyl boron, tetramethyl ammonium n-dodecyl triphenyl boron, tetramethyl ammonium methyl tri-p-tolyl boron, tetramethyl ammonium n-butyl tri-p
-Tolyl boron, tetramethyl ammonium n-octyl tri-p-tolyl boron, tetramethyl ammonium n-dodecyl tri-p-tolyl boron, tetramethyl ammonium methyl trianisyl boron, tetramethyl ammonium n-butyl trianisyl boron, tetramethyl ammonium n -Octyltrianisyl boron, tetramethyl ammonium n-dodecyl trianisyl boron, tetraethyl ammonium n-methyl triphenyl boron, tetraethyl ammonium n-butyl triphenyl boron, tetraethyl ammonium n-octyl triphenyl boron, tetraethyl ammonium n-dodecyl triphenyl Boron, tetraethyl ammonium methyl tri-p-tolyl boron, tetrabutyl ammonium n-butyl trif Such as Niruhou arsenide, and the like. These decoloring agents may be used alone or in combination of two or more.

The amount of the decoloring agent used is preferably at least 1 part, more preferably at least 5 parts with respect to 100 parts of the coloring agent in order to improve the decoloring property. In order to improve the light fastness of prints and images formed using toner, and to prevent discoloration and fading, 50
Parts or less, more preferably 20 parts or less.

The method for producing the decolorizable toner of the present invention is not particularly limited, and the toner can be produced by, for example, mixing the raw materials and producing the same as in a normal toner.

For example, the colorant and the decolorant may be dispersed in the resin A by mixing the resin A, the colorant, and the decolorant and then heating and kneading the mixture.

In producing the decolorizable toner, a toner property imparting agent may be added as necessary.

Examples of the toner property imparting agent include a chargeable substance, an anti-fading agent, a white filler, an ultraviolet absorber, a plasticizer, a lubricant and the like.

Representative examples of the chargeable substance include a charge control agent.

Examples of the charge control agent include positive charge control agents such as quaternary ammonium salts, alkylamides, and hydrophobic silicas; diaminoanthraquinones, chlorinated polyolefins, chlorinated polyesters, metal salts of naphthenic acids, and metal salts of fatty acids. And the like.

The charge control agent is generally available as a commercial product, and typical examples of such a product include Bontron P-51 (Orient Chemical Co., Ltd.) which is a positive charge control agent for a quaternary ammonium salt. Industrial Co., Ltd.
TP-415 (manufactured by Hodogaya Chemical Industry Co., Ltd.), Kayacharge N-3 (manufactured by Nippon Kayaku Co., Ltd.) which is a negative charge control agent, and a negative charge control agent of calixarene. Bontron E-89 (Orient Chemical Industry Co., Ltd.)
Manufactured).

The amount of the chargeable substance may be appropriately adjusted according to the charge amount of the target decolorizable toner. If the amount of the chargeable substance is too large, the resulting decolorizable toner tends to have poor moisture resistance and poor image stability. Parts or less, more preferably 8 parts or less, and when it is intended to impart a certain degree of chargeability, the blending amount of the chargeable substance is 0.3 parts or more based on 100 parts of the resin A, and furthermore Preferably it is at least 1 part.

When a color fading preventing agent is added to the decolorizable toner of the present invention in advance, a decrease in the image density of a printed or copied image of the decolorizable toner can be prevented.
This is because the reaction and decomposition of the colorant in the decolorizable toner due to light and heat are suppressed.

When the toner property-imparting agent is added, the toner property-imparting agent may be dissolved in an organic solvent, if necessary, added and kneaded to volatilize and remove the organic solvent.

The above-mentioned heat-melt kneading can be usually carried out using a kneader, roll, kneading extruder or the like. After kneading so as to have a uniform composition, the mixture is cooled, and the obtained kneaded material is pulverized to a predetermined particle size. The pulverization can be performed by, for example, a cutter mill, a jet pulverizer, or the like. After the pulverization, if necessary, classification may be performed using an air classifier or the like in order to obtain a predetermined particle size.

If the average particle diameter of the decolorizable toner is too small, the cost tends to increase. Therefore, the average particle diameter is preferably 5 μm or more, more preferably 8 μm or more. Has a tendency that it is difficult to obtain a clear toner image.
More preferably, it is 20 μm or less.

The decolorizable toner of the present invention may be manufactured by separately dispersing different types of colorants in the resin A and the resin B incompatible with each other, and then dispersing the colorants in the resin A. In this case, since different types of colorants are contained in different domains composed of the colorants and the resin B, contact between the domains is prevented via the resin A, and direct contact between the colorants is avoided. Can be Therefore, it is possible to prevent a change in the color tone of the decolorizable toner due to the interaction between the different types of colorants, and a change in the color tone of an image formed using the decolorizable toner. Further, by adjusting at least one of the type of the resin B and the amount of the resin B used, the decoloring property of the decolorizable toner can be adjusted.

As the resin B, for example,
From among those exemplified as above, those other than those actually used as the resin A and incompatible with the resin A may be selected and used.

Further, the usage ratio of the resin (B) to the coloring agent and the decoloring agent may be in accordance with the usage ratio of the resin A to the coloring agent and the decoloring agent.

When a decolorizable toner is produced using particles (also referred to as toner particles) in which a colorant, a decoloring agent, etc. are dispersed in the resin (B), the toner particles are dispersed in the resin (A). What is necessary is just to make it.

The decolorizable toner according to the present invention has a chroma (C) of 12 or less, more preferably 10 or less, and especially 4 or less in Munsell color specification.
It is preferable from the point of view. If the saturation (C) is larger than 12, the characters tend to be dazzling and tired when reading characters.

The decolorability of the decolorizable toner of the present invention can be evaluated, for example, by the following method.

That is, the decolorizable toner is dissolved in an organic solvent such as dichloromethane or acetone, applied to an overhead print film, and then air-dried to form a coating film having a thickness of about 10 μm. The reflection density (density A) of the formed coating film is measured with a Macbeth densitometer.

Next, the coating film was irradiated with a halogen lamp for a predetermined time (T time) to erase the color, and the reflection density (density B) was measured in the same manner as described above. (Et)] = [(density A−density B) / density A]
The decoloring rate (Et) is determined according to × 100.

In the present invention, near-infrared rays are
If the erasing rate (Et) after irradiation for seconds is 95% or more, it can be said that the erasing property is good.

Further, different kinds of colorants are separately dispersed in the resin A and the resin B which is incompatible with each other.
When the decolorizable toner is obtained by a manufacturing method of dispersing the colorants, it is desirable that the decolorization rates of the different domains composed of the respective colorants and the resin B are substantially equal to each other. For example, let E (a) T be the color erasing rate of the domain composed of colorant a and resin B after irradiation T time, and the color erasing rate of domain composed of colorant b and resin B after irradiation T time. To E (b) T
| E (a) T−E (b) T | is preferably about 10% or less, preferably about 5% or less.

The image fixed on an image support made of, for example, paper using the decolorizable toner of the present invention is
Characters are easy to read. Further, after printing and fixing, the printed portion can be decolorized by irradiating visible light to near-infrared light by means such as a semiconductor laser, a halogen lamp, and a light emitting diode. And
After the printed portion is erased, printing can be performed again by overlapping the erased portion. Therefore, the decolorizable toner of the present invention can be used, for example, for image supports such as copy paper, and for tickets that can be printed repeatedly at the time of boarding, erased at the time of getting off, and used repeatedly, and tickets for boarding tickets and various admission tickets. It can be suitably used for printing.

[0077]

EXAMPLES Next, the decolorizable toner of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to only these Examples.

The evaluation methods used in the following examples and comparative examples are summarized below.

(Color erasing property) A sample before color erasing (color erasable toner printing paper, adjusted so as to have a Macbeth density of 0.8) is irradiated with a halogen lamp for a predetermined time to decolor the sample, and then a Macbeth densitometer ( The image density after erasing was measured with no color filter), and evaluated according to the following criteria.

[0080]

(Visibility) The chroma of the sample before decolorization was measured with a colorimetric color difference meter “ZE- # 2000” manufactured by Nippon Denshoku Industries Co., Ltd. The higher the saturation, the more dazzling and the worse the visibility. Conversely, the lower the saturation, the less glare the better the visibility.

Examples 1-4 and Comparative Examples 1-5 97 parts of a polyester resin ("FC-714" manufactured by Mitsubishi Rayon Co., Ltd.) as a matrix resin (resin A), polypropylene wax (manufactured by Sanyo Chemical Industries, Ltd.) "R-
972 "), 0.5 part of a white filler (titanium oxide:" STR-60 ", manufactured by Showa Denko KK), and a decolorizing agent (tetrabutylammonium n-butyltriphenylboron)
3 parts and 1 part of each colorant mixture described in Table 2 were mixed and melt-kneaded using a kneading extruder.

After cooling the obtained kneaded product, it was pulverized using a cutter mill and a jet mill to obtain an average particle size of 11 μm.
Was obtained.

The contents of Dyes 1 to 5 in Table 2 are shown in Table 3.
Shown in

Using the obtained decolorizable toner, a decolorizable toner copy was formed by the following method.

5 parts of decolorizable toner and a silicone resin-coated ferrite carrier (F95-
100 ") and 95 parts thereof were uniformly mixed using a V-type blender to obtain a two-component developer.

The obtained developer was set in a commercially available copying machine (“FT-4525” manufactured by Ricoh Co., Ltd.), and copying was performed using black solid as an original at various printing densities.

The reflection density of the obtained printed copy was measured with a Macbeth densitometer (without a color filter), and the sample having an image density of 0.8 was used as a sample before the decolorizing treatment. The decolorability and the visibility were evaluated using the sample before the decolorization treatment. Table 2 shows the results.

[0089]

[Table 8]

[0090]

[Table 9]

[0091]

When the decolorizable toner of the present invention is used, the energy of light used for decoloring can be efficiently used for the decoloring reaction, and the decoloring property is improved. Also, by mixing two or three kinds of coloring agents (dyes), the saturation becomes low, fine characters and the like become easy to read, and eyes are hardly tired.

Claims (5)

[Claims] 1. A color erasable toner by light, the general formula ^{(I): Z + · A} - (I) ( wherein the cation Z ⁺ is having an absorption in the near infrared region from the visible light region , A ^- boron ions, halogen ions, perchloric acid ions, PF ₆ is _{^{-, BF 4 -, SbF 6}} -, OH - and R-SO ₃ ^- anion selected from, wherein, R is an alkyl group, an aryl group , Aralkyl group, substituted alkyl group,
Two kinds of colorants having different hues belonging to the colorant represented by the formula (II): (Wherein, R ^{1 to} R ⁸ each independently represent a hydrogen atom, an alkyl group, an alicyclic group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a silyl group, a heterocyclic group, a substituted alkyl group, An alicyclic group, a substituted aryl group, a substituted aralkyl group, a substituted alkenyl group, a substituted alkynyl group or a substituted silyl group), the absorption peaks of the two colorants in the visible light region. A decolorizable toner having a peak top separated by 20 nm or more. 2. A toner capable of decoloring by light, comprising three kinds of colorants having different hues belonging to the colorant represented by the general formula (I) and the decolorant represented by the general formula (II). A decolorizable toner, wherein the peak tops of the absorption peaks in the visible light region of each of the three colorants are separated from each other by 20 nm or more. 3. One of the three colorants belonging to the colorant represented by the general formula (I), wherein the hue in the Munsell color specification is any one of G, BG, B, and PB, and Is P, RP, or R, and one of the residues is YR,
The decolorizable toner according to claim 2, which is any one of Y and GY. 4. One of three colorants belonging to the colorant represented by the general formula (I) has a peak top of an absorption peak at 400 to 500 nm, and one of the colorants has a peak top of 500 to 570.
The color erasable toner according to claim 2, wherein the toner has a peak top of an absorption peak at nm, and one of the residues has a peak top of an absorption peak at 570 to 700 nm. 5. The saturation (C) in the Munsell color specification is 12
5. The decolorizable toner according to claim 1, wherein: