JPH05181310A - Near infrared ray discoloring type toner - Google Patents

Abstract

PURPOSE:To provide the toner, which is obtained by including the specified near infrared ray absorbable color and the discoloring agent in the binding resin and which can be discolor the color of the near infrared ray absorbable color quickly by radiating it with the near infrared rays, using the specified thermoplastic resin as the binding resin. CONSTITUTION:This toner is obtained by including the near infrared ray absorbable color expressed by a formula I or a formula II and the discoloring agent expressed by a formula III in the binding resin, and as the binding resin, thermoplastic resin having light permeability at 80% or more is used. In the formulas, X represents halogen ion, perchloric acid ion, PF6-, SbF6- or the like; R<1>-R<4> respectively hydrogen atom, hydrocarbon group or hydrocarbon group including hetero atom; Y cation having the absorbing characteristic in a near infrared ray area; R<5>-R<8> respectively alkyl group and aryl group or the like; and at least one of R<5>-R<8> alkyl group having 1-12 of carbon; R<9>-R<12> respectively hydrogen atom and alkyl group or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a near infrared ray erasable toner. More specifically, it relates to a near-infrared erasable toner capable of visualizing an electric latent image or electric signal in an electrophotographic or electrostatic recording material.

[0002]

2. Description of the Related Art In recent years, the reuse and recycling of used paper has been reviewed to protect nature, especially to protect forest resources and reduce waste in urban areas. As part of this, the reuse of used copy paper, printed matter, facsimile paper, etc. that has become unnecessary in the offices of companies is being studied.

However, since most of these papers are company confidential documents, which are generally regarded as trade secrets, it is extremely difficult to collect and recycle these papers outside the company. Yes, and because the recorded and printed parts of printed matter, copies, etc. cannot be easily erased, they must be incinerated or crushed and discarded.
It was thought that such recycling of papers was practically impossible.

[0004]

Therefore, as a result of intensive studies conducted by the present inventors in view of the above-mentioned prior art, the near infrared light erasable recording capable of absorbing, decomposing and erasing near infrared rays. The material has been found, and a toner using such a recording material has been developed (Japanese Patent Application No. 2-194187).

When electrostatic copying is performed using the toner, the image, print, etc. recorded on the copy paper can be erased by irradiating near infrared rays, and electrostatic copying is performed again after erasing. This makes it possible to reuse the copy paper, and when the used copy paper is discarded, the recorded images, prints, etc. can be erased by irradiating with near-infrared rays. There are many advantages such as the ability to prevent the paper from being ejected, and at the same time, it becomes possible to collect and recycle the copy paper.

However, the toner is desired to have an improved decoloring speed when irradiated with near-infrared rays in order to erase images, prints and the like formed on copy paper, and to make an afterimage invisible after decolorization. ing.

The present invention has been made in view of such a toner, and an object of the present invention is to provide a toner having a high erasing speed and having almost no afterimage after erasing.

[0008]

That is, the present invention provides a binder resin having the general formula (I):

[0009]

[Chemical 4]

(Wherein X represents a halogen ion, a perchlorate ion, PF ₆ ⁻ , SbF ₆ ⁻ , OH ⁻ , a sulfonate ion or BF ₄ ⁻ ) or the general formula (II):

[0011]

[Chemical 5]

(In the formula, R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a hydrocarbon group or a hydrocarbon group containing a hetero atom; Y is a cation having an absorption characteristic in the near infrared region. A near-infrared absorbing dye represented by (showing an ion) and the general formula (III):

[0013]

[Chemical 6]

(In the formula, R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group, an alkynyl group, a silyl group,
A heterocyclic group, a substituted alkyl group, a substituted aryl group, a substituted allyl group, a substituted aralkyl group, a substituted alkenyl group, a substituted alkynyl group or a substituted silyl group, and R ⁵ , R ⁶ and R ⁷
And at least one of R ⁸ is an alkyl group having 1 to 12 carbon atoms; R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each independently a hydrogen atom, an alkyl group, an aryl group, an allyl group, an aralkyl group or an alkenyl. Group, an alkynyl group, a heterocyclic group, a substituted alkyl group, a substituted aryl group, a substituted allyl group, a substituted aralkyl group, a substituted alkenyl group or a substituted alkynyl group). The present invention relates to a near-infrared decolorizable toner characterized by using a thermoplastic resin having a light transmittance of 80% or more as a binding resin.

[0015]

When the near-infrared color erasable toner of the present invention is formed on an image support such as copying paper, the toner is rapidly and uniformly erased when irradiated with near-infrared rays. Coloring can be performed, and almost no afterimage is left after the erasing process.

As the binder resin used in the decolorizable toner of the present invention, a thermoplastic resin having a light transmittance of 80% or more is used so that an afterimage is hardly left after the decoloring treatment. It is used, but it is preferable to use a thermoplastic resin having a light transmittance of 85% or more.

The light transmittance referred to in the present specification means JI
S K6717: A value measured according to the method specified in Section 4.5 (1977).

In the present invention, the light transmittance is
It was measured using a direct reading haze meter manufactured by Toyo Seiki Seisakusho.

Specific examples of the thermoplastic resin include polystyrene homopolymer, hydrogenated polystyrene, styrene-propylene copolymer, styrene-isobutylene copolymer, styrene-butadiene copolymer, styrene-allyl alcohol copolymer. , Styrene-maleic acid ester copolymer, styrene-maleic anhydride copolymer, acrylonitrile-butadiene-styrene terpolymer, acrylonitrile-styrene-acrylic acid ester terpolymer, styrene-acrylonitrile copolymer, Polystyrene resin such as acrylonitrile-acrylic rubber-styrene terpolymer, acrylonitrile-chlorinated polyethylene-styrene terpolymer; polymethylmethacrylate, polyethylmethacrylate, polybutylmethacrylate, polyglycy Methacrylate,
Acrylic resin such as fluorinated acrylate-methyl methacrylate-butyl methacrylate copolymer, ethyl acrylate-acrylic acid copolymer; styrene-acrylic acid copolymer, styrene-butadiene-acrylic acid ester copolymer, styrene-methyl Methacrylate copolymer, styrene-butylmethacrylate copolymer, styrene-diethylaminoethylmethacrylate copolymer, styrene-methylmethacrylate-butylacrylate terpolymer, styrene-glycidylmethacrylate copolymer, styrene-butadiene-dimethylaminoethyl Styrene- (meth) acrylic acid ester such as methacrylate terpolymer, styrene-acrylic acid ester-maleic acid ester terpolymer, styrene-butyl acrylate-acrylic acid terpolymer Copolymer and the like, these resins may be used alone or as a mixture of two or more.

In the present invention, the near infrared absorbing dye has the general formula (I):

[0021]

[Chemical 7]

(Wherein X represents a halogen ion, a perchlorate ion, PF ₆ ⁻ , SbF ₆ ⁻ , OH ⁻ , a sulfonate ion or BF ₄ ⁻ ) or the general formula (II):

[0023]

[Chemical 8]

(In the formula, R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a hydrocarbon group or a hydrocarbon group containing a hetero atom; Y is a positive atom having absorption characteristics in the near infrared region. The one represented by (showing ions) is used.

Examples of the halogen ion include fluorine ion, chlorine ion, bromine ion and iodine ion, and examples of the sulfonate ion include methyl sulfonate ion such as CH ₃ SO ₃ ⁻ and FCH.
₂ SO ₃ ⁻ , F ₂ CHSO ₃ ⁻ , F ₃ CSO ₃ ⁻ , Cl
^{_{CH 2 SO 3 -, Cl 2}} CHSO 3 -, Cl 3 CSO 3
^{_{-, CH 3 OCH 2 SO 3}} -, (CH 3) 2 NCH 2 S
O ₃ ^- substituted methyl sulfonate ion such as, C ₆ H ₅ S
O ₃ ^- phenyl sulfonate ion such as, CH ₃ C ₆ H
^{_{4 SO 3 -, (CH 3}} ) 2 C 6 H 3 SO 3 -, (C
_{H 3) 3 C 6 H 2} SO 3 -, HOC 6 H 4 SO 3 -,
_{(HO) 2 C 6 H 3} SO 3 -, (HO) 3 C 6 H 2 SO
^{_{3 -, CH 3 OC 6 H}} 4 SO 3 -, C 6 H 4 ClSO 3
^{_{-, C 6 H 3 Cl 2}} SO 3 -, C 6 H 2 Cl 3 S
O ₃ ⁻ , C ₆ HCl ₄ SO ₃ ⁻ , C ₆ Cl ₅ SO ₃ ⁻ ,
^{_{C 6 H 4 FSO 3 -,}} C 6 H 3 F 2 SO 3 -, C 6 H 2
^{_{F 3 SO 3 -, C 6}} HF 4 SO 3 -, C 6 F 5 S
Substituted phenyl sulfonate ions such as O ₃ ⁻ and (CH ₃ ) ₂ NC ₆ H ₄ SO ₃ ⁻ can be used.

In the general formula (II), R¹, R
², R³And R^FourSpecific examples of
Child, alkyl group, aryl group, allyl group, aralkyl
Group, alkenyl group, alkynyl group, silyl group, heterocycle
Group, substituted alkyl group, substituted aryl group, substituted allyl group,
Substituted aralkyl group, substituted alkenyl group, substituted alkynyl
Group, a substituted silyl group and the like. Of these
Specific examples of preferred compounds include, for example, hydrogen atom,
Nyl group, anisyl group, n-butyl group, n-pentyl group, n-hexyl group
Xyl group, n-heptyl group, n-octyl group, n-dodecyl group
Group, cyclohexyl group, cyclohexenyl group, methoxy
Methyl group, methoxyethyl group, ethoxyphenyl group,
Ruyl group, t-butylphenyl group, fluorophenyl group,
Chlorophenyl group, diethylaminophenyl group, vinyl
Group, allyl group, triphenylsilyl group, dimethylphenyl
Rusilyl group, dibutylphenylsilyl group, trimethylsilane
Ryl group, piperidyl group, thienyl group, furyl group, etc.
You can Also, R¹, R², R ³And R^FourLittle of
At least one is an alkyl group having 1 to 12 carbon atoms
Preferred, but more preferred among such alkyl groups
Examples include, for example, n-butyl group, n-pentyl group, n-
Hexyl group, n-heptyl group, n-octyl group, n-dodecyl
Examples thereof include alkyl groups having 4 to 12 carbon atoms such as groups.

Preferred examples of Y in the near-infrared absorbing dye represented by the general formula (II) include, for example, cyanine, triarylmethane, aminium, diimmonium, thiazine and xanthene, which have absorption characteristics in the near infrared region. Examples include oxazine, styryl and pyrylium-based cationic dyes. As a typical example of such Y, for example,

[0028]

[Chemical 9]

[0029]

[Chemical 10]

And the like.

The amount of the near-infrared absorbing dye compounded is 0.01 to 100 parts by weight of the binder resin (weight part, the same applies hereinafter).
90 parts, preferably 0.5 to 20 parts. When the compounding amount of such near infrared absorbing dye is less than the above range,
If the obtained toner is not sufficiently colored, and if the amount is more than the above range, the triboelectric charge amount peculiar to the obtained toner may be adversely affected.

In the present invention, the general formula (II
I):

[0033]

[Chemical 11]

(Wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group, an alkynyl group, a silyl group,
A heterocyclic group, a substituted alkyl group, a substituted aryl group, a substituted allyl group, a substituted aralkyl group, a substituted alkenyl group, a substituted alkynyl group or a substituted silyl group, and R ⁵ , R ⁶ and R ⁷
And at least one of R ⁸ is an alkyl group having 1 to 12 carbon atoms: R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each independently a hydrogen atom, an alkyl group, an aryl group, an allyl group, an aralkyl group or an alkenyl. Group, an alkynyl group, a heterocyclic group, a substituted alkyl group, a substituted aryl group, a substituted allyl group, a substituted aralkyl group, a substituted alkenyl group or a substituted alkynyl group).

Specific examples of the decoloring agent include tetramethylammonium n-butyltriphenylboron,
Tetramethylammonium n-butyltrianisyl boron, tetramethylammonium n-octyltriphenylboron, tetramethylammonium n-octyltrianisylboron, tetraethylammonium n-butyltriphenylboron, tetraethylammonium n-butyltrianisylboron, tetrabutyl Ammonium n-butyltriphenylboron, tetrabutylammonium n-butyltrianisylboron, tetraoctylammonium n-octyltriphenylboron, tetrabutylammonium
n-dodecyl triphenyl boron, trimethylhydrogen ammonium n-butyl triphenyl boron, triethyl hydrogen ammonium n-butyl triphenyl boron, tetrahydrogen ammonium n-butyl triphenyl boron, tetramethyl ammonium tetrabutyl boron, tetraethyl ammonium tetrabutyl boron,
Tetra n-butyl ammonium tetra n-butyl boron, tetramethyl ammonium tri n-butyl (triphenylsilyl) boron, tetraethyl ammonium tri n-butyl (triphenylsilyl) boron, tetrabutyl ammonium n-butyl (triphenylsilyl) boron , Tetramethylammonium tri-n-butyl (dimethylphenylsilyl) boron, tetraethylammonium tri-n-butyl (dimethylphenylsilyl) boron, tetrabutylammonium tri-n-butyl (dimethylphenylsilyl) boron, tetramethylammoniumn-octyldiphenyl ( Di-n-butylphenylsilyl) boron, tetraethylammonium n-octyldiphenyl (di-n-butylphenylsilyl) boron, tetrabutylammonium n-octyldiphenyl (di-n-butylphenyl) Silyl) boron, tetramethylammonium dimethylphenyl (trimethylsilyl) boron, tetraethylammonium dimethylphenyl (trimethylsilyl) boron, tetrabutylammonium dimethylphenyl (trimethylsilyl) boron, etc., and these decolorizers may be used alone or in combination of two or more. Used as a mixture.

The compounding amount of the decoloring agent cannot be unconditionally determined because it varies depending on the kind of the near-infrared absorbing dye, but usually 1 to 2500 parts per 100 parts of the near-infrared absorbing dye, It is preferably selected from the range of 5 to 1000 parts. When the compounding amount of the decoloring agent is less than the above range, the decoloring speed becomes slow, and when the compounding amount is more than the above range, the light resistance of the printing and image formed by using the obtained toner. It becomes less sexual and discolors and fades.

The decolorizable toner of the present invention contains a binder resin, a near-infrared absorbing dye and a decoloring agent, and if necessary, for example, a wax, an ultraviolet absorber, a charge control agent, a plasticizer, You may mix | blend an appropriate amount of additives, such as a coloring pigment.

The method for preparing the decolorizable toner of the present invention includes a solution method and a melting method.

The solution method means, for example, a near-infrared absorbing dye and a binder resin are dissolved and mixed in an organic solvent, and a decoloring agent and an additive are added thereto and dissolved and mixed, and the resulting mixture is mixed with an organic solvent. Is removed, and then finely pulverized by, for example, a hammer mill, a cutter mill, a jet mill or the like to prepare a toner having an average particle size of about 5 to 30 μm.

In the melting method, for example, a near-infrared absorbing dye is melt-kneaded with a binder resin by heating, a decoloring agent and an additive are added thereto, and the mixture is kneaded and then cooled, followed by the solution method. In the same manner, the toner is prepared by crushing.

The thus-obtained decolorizable toner of the present invention is printed and fixed on an image support made of, for example, paper, and then irradiated with near infrared rays by means such as a semiconductor laser, a halogen lamp and a light emitting diode. The printed part can be erased. Then, after the printed portion is erased, it is possible to print again by overlapping the erased portion again.

By mixing the near infrared ray erasable toner of the present invention with a carrier, a two-component developer can be obtained.

Examples of the carrier include carriers such as glass beads, iron powder, ferrite and magnetite; carriers in which the surface of the carrier is coated with silicone resin, fluorine resin, acrylic resin, styrene resin, etc .; ferrite powder , Magnetite powder, γ-Fe ₂
A carrier in which magnetic powder such as O ₃ powder is dispersed in a resin and adjusted to have a predetermined particle size; metal salicylate, azo-based metal-containing dye, bisazo-based metal-containing dye, diaminoastraquinone, chlorinated polyolefin, chlorine Examples of the carrier include a charge control agent such as a modified polyester, a metal salt of naphthenic acid, a metal salt of fatty acid, a nigrosine dye, an amine compound, a quaternary ammonium salt, carbon and an inorganic oxide.

The amount of the carrier used is usually 10
It is desirable that the amount of the near-infrared decolorizable toner is adjusted to 1 to 20 parts, preferably 2 to 10 parts, relative to 0 part.

Next, the near-infrared color erasable toner of the present invention will be described in detail based on examples, but the present invention is not limited to these examples.

Examples 1 to 10 and Comparative Examples 1 to 5 The raw materials shown in Tables 1 to 4 were weighed in proportions shown in Table 5 so that the total amount would be 800 g. Next, all the raw materials are put into a pressure type kneader having an effective capacity of 2 liters, the kneader is heated, the kneading temperature of the raw materials is adjusted to 120 ° C., and the mixture is kneaded for 5 minutes. Then, the kneaded product is taken out from the kneader and cooled. And solidified.

The solidified product obtained was pulverized by a jet mill, and then a wind classifier was used to obtain toner particles having an average particle diameter of about 11 μm. R-972 (Japan) was used as hydrophobic silica for the toner particles. Aerosil Co., Ltd., trade name) 0.2
% By weight was added and mixed with a Henschel mixer to obtain a toner.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

[Table 4]

The physical properties of the toner thus obtained were examined for print marks after the decoloring treatment according to the following method. The results are shown in Table 5.

(Print mark after decoloring treatment) 100 parts of silicone resin coated carrier (F97-2535 manufactured by Powder Tech Co.) was mixed with 4 parts of toner so as to have a uniform composition, and a developer was mixed. Prepared.

The obtained developer is used as a copying machine manufactured by Sanyo Electric Co., Ltd.
Put into SFT-70 The Institute of Electrophotography Test Chart No.1-R1975
Was used to make a copy on PPC paper.

The erasability was evaluated by irradiating the obtained copy with a dichroic coat type halogen lamp (2 W / cm ² ) as a near-infrared light source for 2 seconds, and then randomly including the non-copy. The sheet was attached to a vertical wall surface, and the printed matter and the unprinted matter were visually identified from a distance of 5 m. This identification was carried out by a total of 10 persons, including 5 males and 5 females. Based on the following evaluation criteria, the total number of 10 persons is 1 when the printed matter that has been erased after printing is regarded as unprinted. Evaluated.

(Evaluation criteria) A: 40 to 50 points B: 30 to 39 points C: 20 to 29 points D: 0 to 19 points

[0057]

[Table 5]

From the results shown in Table 5, all of the near-infrared decolorizable toners obtained in Examples 1 to 10 in which a thermoplastic resin having a light transmittance of 80% or more was used as a binder resin, were erased. It can be seen that even after the color time is short, the afterimage hardly exists after the color is erased.

[0059]

INDUSTRIAL APPLICABILITY The near-infrared erasable toner of the present invention is capable of rapidly erasing the color of the near-infrared absorbing dye only by irradiating it with near-infrared rays. When applied to the above, printing and erasing can be repeated.

Therefore, when the decolorizable toner of the present invention is used, the image support can be reused, and at the same time, when it is discarded, the recorded portion can be erased by irradiating it with near infrared rays in advance. Thus, it is possible to prevent the secret item from being known to a third party.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 17, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

Examples of the carrier include carriers such as glass beads, iron powder, ferrite and magnetite; carriers in which the surface of the carrier is coated with silicone resin, fluorine resin, acrylic resin, styrene resin, etc .; ferrite powder , Magnetite powder, γ-Fe ₂
O ₃ magnetic powder, such as powder dispersed in a resin, the carrier was adjusted into a predetermined particle size, salicylic acid metal salts, azo metal complex dyes, bisazo metal complex dyes, Jiaminoa down Torakino <br/> down, Examples include carriers containing a charge control agent such as chlorinated polyolefin, chlorinated polyester, naphthenic acid metal salt, fatty acid metal salt, nigrosine dye, amine compound, quaternary ammonium salt, carbon and inorganic oxide.

[Procedure amendment]

[Submission date] March 18, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

The decolorizable toner of the present invention, binder resin, but those containing a near infrared absorptive dye and the discoloring agent, if necessary, such as waxes, UV absorbers, a charge control agent, a plasticizer, You may mix | blend an appropriate amount of additives, such as a coloring pigment.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction content]

[0038] to a method for the preparation of the decolorizable toner of the present invention, there is a solution method and a melting method.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

[0039] and the solution method, for example a near infrared absorbing dye and the binder resin were dissolved and mixed in an organic solvent, to which the decolorizer, and then dissolved and mixed together by blending an additive, organic from the obtained mixture After removing the solvent, for example, a hammer mill,
This is a method in which a toner having an average particle diameter of about 5 to 30 μm is prepared by finely pulverizing with a cutter mill, a jet mill or the like.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

[0041] Thus decolorizable toner of the present invention as example, for example after printing fixed on an image support made of paper, for example a semiconductor laser, a halogen lamp, by irradiating near infrared rays by means such as a light emitting diode The printed part can be erased. Then, after the printed portion is erased, it is possible to print again by overlapping the erased portion again.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0057

[Correction method] Change

[Correction content]

[0057]

[Table 5]

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Change

[Correction content]

[0060] Thus, by using the decolorizable toner of the present invention, it can be performed to erase the recorded portion if previously irradiated with near infrared rays to the disposal and at the same time it is possible to reuse the image support Thus, it is possible to prevent the secret item from being known to a third party.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number in the agency FI Technical indication location G03G 9/08 361 365 (72) Inventor Kiichi Hosoda 5-1 Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa (72) Inventor Toshio Arai, 3-2-15, Meiwadori, Hyogo-ku, Kobe, Hyogo Prefecture Bando Kagaku Co., Ltd.

Claims (1)

[Claims] 1. The binder resin has the general formula (I): (In the formula, X is halogen ion, perchlorate ion, PF _{6
^{-, SbF 6 -, OH -}} , sulfonic acid ion or BF
₄ ^- shows a) or general formula (II): ## STR2 ## (In the formula, R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a hydrocarbon group or a hydrocarbon group containing a hetero atom; Y is a cation having an absorption property in the near infrared region. ) Near-infrared absorbing dye and the general formula (II
I): [Chemical 3] (In the formula, R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group, an aryl group, an allyl group, an aralkyl group,
An alkenyl group, an alkynyl group, a silyl group, a heterocyclic group, a substituted alkyl group, a substituted aryl group, a substituted allyl group, a substituted aralkyl group, a substituted alkenyl group, a substituted alkynyl group or a substituted silyl group, R ⁵ , R ⁶ and R ⁷ and R
^At least one of 8 is an alkyl group having 1 to 12 carbon atoms; R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each independently a hydrogen atom, an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group, Alkynyl group, heterocyclic group, substituted alkyl group, substituted aryl group, substituted allyl group, substituted aralkyl group, substituted alkenyl group or substituted alkynyl group). A near-infrared decolorizable toner characterized by using a thermoplastic resin having a light transmittance of 80% or more as a wearing resin.