JPH05241369A - Decoloring toner under near infrared ray - Google Patents

Abstract

PURPOSE:To ensure high stability and to prevent decoloration and discoloration by adding an image stabilizing agent to a decoloring toner obtd. by incorporating one of specified near IR absorbing dyes and a decoloring agent into a binding resin. CONSTITUTION:One of compds. represented by formulae I, II is used as a near IR absorbing dye and a compd. represented by formula III is used as a decoloring agent. In the formula I, X is a halogen ion, a perchlorate ion, PF6<->, OH<->, a sulfonate ion or BF4<-> and Y is a cation having absorbing characteristics in a near IR region. In the formula II, each of R<1>-R<4> is H or a hydrocarbon group optionally contg. a hetero atom. In the formula III, each of R<5>-R<8> is alkyl or substd. silyl, at least one of R<5>-R<8> is 1-12C alkyl and each of R<9>-R<12> is H, etc.

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 waste paper such as used copy paper, printed matter, and facsimile paper that has become unnecessary in the office of a company is being studied.

Therefore, a company has put a paper manufacturing company in a group, collects waste paper, melts it, reprocesses it as recycled paper, and reuses it, but these papers are generally regarded as trade secrets. Since most of the company's internal confidential documents are
It is extremely difficult to collect and recycle these papers at a paper manufacturing company outside the company, and since the recorded parts and printed parts of printed matter, copied matter, etc. cannot be easily erased, they can be incinerated or burned. It had to be crushed and discarded, and it was thought that it would be virtually impossible to reuse such papers. In addition, although some studies have been conducted on the recycling of waste paper crushed by shredders, etc., recycled paper manufactured using such crushed waste paper generally has low strength. It has a drawback that it cannot be used as information paper.

[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 only irradiating the near infrared rays, and electrostatic copying is performed again after the 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 near-infrared absorbing dyes and decolorizing agents used in the toner are decolored or faded due to heating during kneading of the toner raw material or heat generated by mechanical shearing, or during storage. There is a drawback that the toner or an image printed using the toner is discolored or faded when it is irradiated with natural light or fluorescent light.

The present invention has been made in order to solve the above drawbacks, and it is possible to obtain a near-infrared absorbing dye even if it is heated at the time of kneading, or is irradiated with natural light or fluorescent light during storage or after printing image formation. It is an object of the present invention to provide a near-infrared decolorizable toner which has improved stability and is hardly affected by decolorization and fading.

[0008]

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

[0009]

[Chemical 4]

(In the formula, X is a halogen ion, perchlorate ion, PF ₆ ⁻ , SbF ₆ ⁻ , OH ⁻ , sulfonate ion or BF ₄ ⁻ , and Y is a cation having an absorption property in the near infrared region. And a near-infrared absorbing dye represented by the general formula (II):

[0011]

[Chemical 5]

Near infrared absorption represented by the formula (wherein 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 the same as above) At least one near-infrared absorbing dye selected from organic dyes 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). A near-infrared color erasable toner characterized by containing an image stabilizer in a binder resin.

[0015]

Working and Examples The near-infrared color erasable toner of the present invention can be applied to an image support such as a copy paper even when it is heated during the kneading of the raw materials for the toner, and using the erasable toner. Even if it is exposed to natural light during storage before forming a print, image, etc. on it, erasing, discoloration,
Since it is hard to fade, it has excellent heat stability and storage stability.

As the binder resin used in the decolorizable toner of the present invention, for example, polystyrene resin represented by polystyrene or the like; polyester resin represented by saturated polyester or unsaturated polyester; epoxy resin; polymethyl (Meth) acrylic resin represented by methacrylate, polyhydroxyethyl acrylate, polyhydroxypropyl acrylate, etc .; silicone resin; fluorine resin; polyamide resin; polyvinyl alcohol resin; polyurethane resin; polyolefin resin such as polyethylene; polyvinyl Butyral; Phenol formaldehyde resin; Rosin-modified phenol formaldehyde resin; Polyacrylonitrile resin; Polyvinyl acetate resin; Phenol resin; Styrene-methylmethacrylate Copolymer, styrene-butyl acrylate-butyl methacrylate copolymer, styrene-butyl acrylate-methyl methacrylate copolymer, styrene-hydroxyethyl acrylate copolymer, styrene-acrylic acid ester-hydroxyethyl acrylate copolymer, styrene- Styrene-acrylic copolymer such as hydroxypropyl acrylate copolymer, styrene-acrylic acid ester-hydroxyethyl acrylate copolymer, styrene-2-ethylhexyl acrylate copolymer, styrene-butyl acrylate-2-ethylhexyl acrylate copolymer Coal; styrene-acrylonitrile copolymer, styrene-acrylic rubber-acrylonitrile copolymer, styrene-EPDM-acrylonitrile copolymer, styrene-butane Styrene-acrylonitrile copolymers such as ene-acrylonitrile copolymers and styrene-chlorinated polyethylene-acrylonitrile copolymers; ethylene-vinyl acetate copolymers, modified ethylene-vinyl acetate copolymers such as ethylene-vinyl acetate Examples thereof include ethylene-acrylic acid copolymers, but the present invention is not limited to these examples. These binding resins are usually used alone or in admixture of two or more. Among these binder resins, the binder resin itself has a large polarity, for example, polyester resin, epoxy resin, (meth) acrylic resin, polyurethane resin, polyacrylonitrile resin, phenol resin, styrene-acryl. Binder resins with large polarity having at least one group selected from a hydroxyl group, a cyano group, a carboxyl group and a carbonyl group in the molecule, such as a styrene-based copolymer and a styrene-acrylonitrile-based copolymer, have further excellent discoloration. Since it imparts preventive properties, it can be particularly preferably used in the present invention.

The compounding amount of the binder resin having a large polarity is
Since the magnitude of the polarity varies depending on the type of polar group present in the binder resin, it cannot be unconditionally determined, but in order to sufficiently improve the fading prevention property, it is usually 5 in the binder resin. It is preferable to adjust the content to be not less than 10% by weight, especially not less than 10% by weight.

In the present invention, the binder resin may be blended with a wax such as a polyolefin wax such as polypropylene wax or a paraffin wax, if necessary. The blending amount of such wax is
In order to fully bring out the effect of blending such a wax, it is desirable that the amount is 0.1 part or more, preferably 0.5 part or more with respect to 100 parts (weight part, the same applies hereinafter) of the binder resin. If the blending amount is too large, film formation on the photoreceptor that forms an electrical latent image tends to occur, so 20 parts or less, preferably 10 parts or less, relative to 100 parts of the binder resin is used. Is desirable.

The image stabilizer used in the present invention has a function of preventing the near-infrared absorptive dye from fading, discoloring or fading due to heating, irradiation of natural light, irradiation of fluorescent light, etc. In the above, at least one selected from heat-resistant antioxidants, metal oxides and metal soaps can be used. Although the reason why the image stabilizer used in the present invention exhibits such an action is not clear, it is probable that the heat-resistant antioxidant has a phenolic hydroxyl group and the like, and the metal oxide has a basic polar group on its surface. It is considered that the groups are present and that the metal soap has an ionic polar group such as a carboxyl group on the surface thereof. That is, the near-infrared absorbing dye used in the near-infrared decolorizable toner of the present invention is an ionic complex,
It is considered that the presence of the anionic polar group stabilizes the ion pair of the complex, which increases the stability of the near-infrared absorbing dye to light and heat. Therefore, due to such properties, when the heat-resistant antioxidant, metal oxide or metal soap is present at the same time as the near-infrared absorbing dye used in the toner, the near-infrared absorbing dye becomes stable, and discoloration, discoloration or fading occurs. Is considered to be prevented.

As the heat resistant anti-aging agent, the decolorizable toner obtained is not contaminated when it is transferred and fixed on an image support such as paper, and white color such as copying paper is used. When it is applied to a sheet having a color, it is preferable to use a color close to white or a light color.

Specific examples of the heat resistant anti-aging agent include:
For example, hydroquinone derivative anti-aging agents such as 2,5-dihydroquinone, 2,5-di-t-amylhydroquinone, 2,5-di-t-butylhydroquinone and hydroquinone monoethyl ether; methyl p-hydroxybenzoate, Ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, 3,4-hydroxyphenyl-p-tolylsulfone, gallic acid n-Propyl, lauryl gallate, resorcinol, 1-oxy-3-methyl-4-isopropylbenzene, 2,6-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6- J-t
-Butyl-4-methylphenol, 2,6-di-t-butyl-4-sec-butylphenol, butylhydroxyanisole, 2,6-di-t-butyl-α-dimethylamino-p-cresol, 2- ( 1-Methylcyclohexyl) -4,6-dimethylphenol, styrenated phenol, alkylated phenol and other alkylated phenol-based and phenol derivative-based antiaging agents;
3-tris- (2-methyl-4-hydroxy-5-t-
Butylphenyl) butane, 4,4'-butylidene bis-
(3-methyl-6-t-butylphenol), 2,2-
Thiobis (4-methyl-6-t-butylphenol),
n-octadecyl-3- (4'-hydroxy-3 ', 5
'-Di-t-butylphenyl) propionate and other hindered phenolic antioxidants; tris (nonylphenyl) phosphite, tris (mixed mono and di-nonylphenyl) phosphite, phenyldiisodecylphosphite, diphenylmono (2 -Ethylhexyl) phosphite, diphenyl monotridecyl phosphite, diphenyl isodecyl phosphite, diphenyl isooctyl phosphite, triphenyl phosphite, tris (tridecyl) phosphite, tetraphenyl dipropylene glycol phosphite and other phosphites. There are non-contaminating heat-resistant anti-aging agents that hardly contaminate white copying paper such as diphenylamine and anti-aging agents. These heat-resistant anti-aging agents can be used alone or in 2
It is used as a mixture of two or more species. Among these heat-resistant anti-aging agents, hydroquinone derivative anti-aging agents and phenol derivative anti-aging agents have good compatibility with styrene-based binder resins and significantly prevent deterioration of crystalline resins due to light rays. It is preferable because it has the property of

The amount of the heat resistant anti-aging agent to be blended is 0.05 to 30 parts, preferably 0.5 to 30 parts, relative to 100 parts of the binding resin.
It is 10 parts, more preferably 0.5 to 2 parts. When the amount of the heat-resistant antiaging agent is less than the above range, the effect of preventing fading of the near-infrared absorbing dye becomes insufficient, and when the amount exceeds the above range, no more is added. Increasing the quantity not only increases the cost, but also
The coloring property of the near-infrared absorbing dye becomes insufficient.

Specific examples of the metal oxide include, for example, MgO, Al ₂ O ₃ , SiO ₂ , Na ₂ O and SiO _2.
・ MgO, SiO ₂・ Al ₂ O ₃ , Al ₂ O ₃・ Na ₂
O · CO _2, such as _{MgO · Al 2 O 3 · CO} 2 and the like, these metal oxides may be used alone or in combination. Among these metal oxides, Mg
O, a mixture of MgO and SiO ₂ or Al ₂ O ₃ , N
a ₂ O, SiO ₂ · MgO, SiO ₂ · Al ₂ O ₃ , A
l ₂ O ₃ , Na ₂ O / CO ₂ , MgO / Al ₂ O ₃ / C
O _{2 and the} like are preferable.

The amount of the metal oxide blended is 10% for the binder resin.
It is desirable that the amount is 1 to 50 parts, preferably 5 to 20 parts, relative to 0 part. When the compounding amount of the metal oxide is more than the above range, the color density of the toner tends to be low due to the coloring property of the metal oxide, and when it is less than the above range, it is sufficient. The effect of preventing fading tends to be lost.

When the amount of the metal oxide compounded is 5 parts or more with respect to 100 parts of the binder resin, white decolorizing paper generally used in electrophotography is used in the decolorizing type of the present invention. After forming an image using toner, when the image is erased by irradiating it with near-infrared rays, the erased image part shows a white color similar to that of copy paper, and suppresses the gloss unique to the binder resin. Since the glossiness is similar to that of copying paper, there is an advantage that it is difficult to distinguish between an image forming portion and a non-image forming portion after decoloring. Such an advantage is remarkable when a metal oxide containing MgO is used among the image stabilizers, and MgO, the metal oxide containing the MgO and a mixture thereof are further used for printing and image formation. Since it does not sometimes impair the color developability of the toner, it can be particularly preferably used in the present invention.

If the average particle size of the metal oxide as an image stabilizer is too large, the quality of the image may be impaired. Therefore, the average particle size is usually 5 μm or less, especially 1 μm or less. Is preferred. In addition, the shape and color of the particles are not particularly limited, but in order to eliminate the gloss of the binder resin and eliminate the traces when the formed prints and images are erased, the shape of the particles is spherical or elliptical. It is desirable that the color is white, since the color of electrophotographic copying paper is generally white.

Specific examples of the metal soap include stearates such as lithium stearate, magnesium stearate, aluminum stearate, calcium stearate, strontium stearate, barium stearate, zinc stearate, cadmium stearate and lead stearate. Acid salts; lauric acid salts such as cadmium laurate, zinc laurate, calcium laurate, barium laurate; chlorostearate salts such as calcium chlorostearate, barium chlorostearate, cadmium chlorostearate; 2-ethylhexylate barium, 2 2-zinc ethylhexylate, cadmium 2-ethylhexylate, lead 2-ethylhexylate and other 2-ethylhexylates; barium ricinoleate,
Ricinoleate such as zinc ricinoleate and cadmium ricinoleate; Formula: 2PbO.Pb (C ₁₇ H ₃₅ COO) ₂
Such as dibasic lead stearate; salicylates such as lead salicylate, zinc salicylate, tin salicylate, and chromium salicylate; Formula: 3PbO.Pb (C ₄ H ₂ O ₄ ) H ₂ O
Such as tribasic lead maleate; Formula: 2PbO.Pb (C
₈ H ₄ O ₄ ) and other dibasic lead phthalates, and these metal soaps may be used alone or in admixture of two or more. Among these metal soaps, a near infrared erasable toner obtained by using zinc stearate, calcium stearate, magnesium stearate, zinc laurate, calcium laurate, lead salicylate, zinc ricinoleate, barium 2-ethylhexylate, etc. is used. When an image is formed by applying the image, it has a melting point suitable for forming a good image without fog, and is excellent in characteristics such as nontoxicity.

The amount of the above-mentioned metal soap is 100
It is desirable that the amount is 0.05 to 10 parts, preferably 0.1 to 5 parts. When the amount of the metal soap is larger than the above range, the triboelectric charge amount peculiar to the toner tends to be adversely affected, and bleeding on the surface of the near-infrared erasable toner causes adhesion to a photoreceptor or the like. There is a tendency that adverse effects such as contamination occur and cause image defects, and if it is less than the above range, the anti-fading effect tends to be insufficient, and sufficient stability tends to be difficult to obtain. ..

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

[0030]

[Chemical 7]

(In the formula, X is a halogen ion, perchlorate ion, PF ₆ ⁻ , SbF ₆ ⁻ , OH ⁻ , sulfonate ion or BF ₄ ⁻ , and Y is a cation having an absorption property in the near infrared region. ) Near-infrared absorbing dye and the general formula (II):

[0032]

[Chemical 8]

(Wherein 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 the same as described above) At least one selected from the functional dyes is used.

Examples of the halogen ion include fluorine ion, chlorine ion, bromine ion and iodine ion, and examples of the sulfonate ion include CH ₃
Alkyl sulfonate ion such as SO ₃ ⁻ , CH ₃ C ₂ H ₄ SO ₃ ⁻ , FCH ₂ SO ₃ ⁻ , F ₂ CHSO ₃ ⁻ ,
F ₃ CSO ₃ ⁻ , ClCH ₂ SO ₃ ⁻ , Cl ₂ CHSO
^{_{3 -, Cl 3 CSO 3 -}} , CH 3 OCH 2 SO 3 -,
Substituted methyl sulfonate ion such as (CH ₃ ) ₂ NCH ₂ SO ₃ ⁻ , phenyl sulfonate ion such as C ₆ H ₅ SO ₃ ⁻ , CH ₃ C ₆ H ₄ SO ₃ ⁻ , (CH ₃ ) ₂ C _{6
^{H 3 SO 3 -, (CH}} 3) 3 C 6 H 2 SO 3 -, HOC
^{_{6 H 4 SO 3 -, (}} HO) 2 C 6 H 3 SO 3 -, (H
_{O) 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 SO 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
Substituted phenyl sulfonate ions such as F ₅ SO ₃ ⁻ and (CH ₃ ) ₂ NC ₆ H ₄ SO ₃ ⁻ may be mentioned.

In the general formula (II), R ¹ , R
Specific examples of ² , R ³ and R ⁴ include, for example, hydrogen atom, alkyl group, aryl group, allyl group, aralkyl group, alkenyl group, alkynyl group, silyl group, heterocyclic group, substituted alkyl group, substituted aryl group, A substituted allyl group,
Examples thereof include a substituted aralkyl group, a substituted alkenyl group, a substituted alkynyl group and a substituted silyl group. Specific examples of preferable ones among these include, for example, hydrogen atom, phenyl group, anisyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-dodecyl group. , Cyclohexyl group, cyclohexenyl group, methoxymethyl group, methoxyethyl group, ethoxyphenyl group, toluyl group, t-butylphenyl group, fluorophenyl group,
Examples thereof include chlorophenyl group, diethylaminophenyl group, vinyl group, allyl group, triphenylsilyl group, dimethylphenylsilyl group, dibutylphenylsilyl group, trimethylsilyl group, piperidyl group, thienyl group and furyl group. Further, at least one of R ¹ , R ² , R ³ and R ⁴ is preferably an alkyl group having 1 to 12 carbon atoms, and more preferable alkyl group is, for example, n-butyl. Group, n-pentyl group, n-
Examples thereof include alkyl groups having 4 to 12 carbon atoms such as hexyl group, n-heptyl group, n-octyl group and n-dodecyl group.

Preferred examples of Y include cyanine, triarylmethane, aminium, diimmonium, thiazine, which have absorption characteristics in the near infrared region.
Examples include xanthene, oxazine, styryl, pyrylium-based cationic dyes, and the like. As a typical example of such Y, for example,

[0037]

[Chemical 9]

[0038]

[Chemical 10]

And the like.

The compounding amount of the near infrared absorbing dye is 0.01 to 25 parts, preferably 0.1 to 100 parts by weight of the binder resin.
It is desirable to be 15 parts. When the compounding amount of the near-infrared absorbing dye is less than the above range, the obtained near-infrared decolorizable toner is not sufficiently colored, and when it is more than the above range, it is obtained. The triboelectric charge amount specific to the near infrared erasable toner may be adversely affected.

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

[0042]

[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 tri n-butyl (triphenylsilyl) Boron, tetramethylammonium tri-n-butyl (dimethylphenylsilyl) boron, tetraethylammonium tri-n-butyl (dimethylphenylsilyl) boron, tetrabutylammonium tri-n-butyl (dimethylphenylsilyl) boron, tetramethylammonium n-octyldiphenyl (Di-n-butylphenylsilyl) boron, tetraethylammonium n-octyldiphenyl (di-n-butylphenylsilyl) boron, tetrabutylammonium dimethyldiphenylboron, tetrabu Ruammonium di-n-butyldiphenylboron, Tetrabutylammonium n-octyldiphenyl (di-n-butylphenylsilyl) boron, Tetramethylammonium dimethylphenyl (trimethylsilyl) boron, Tetraethylammonium dimethylphenyl (trimethylsilyl) boron, Tetrabutylammonium dimethylphenyl Examples thereof include (trimethylsilyl) boron, and these decolorizing agents may be used alone or in admixture of two or more.

The amount of the decolorizer blended is 1 to 2500 parts, preferably 5 to 1000 parts, relative to 100 parts of the near infrared absorptive dye.
It is a department. When the compounding amount of the decoloring agent is less than the above range, the decoloring speed becomes low, and when it is more than the above range, the obtained near infrared decoloring toner is used. The light resistance of printing and images becomes poor, and the colors fade, discolor, and fade.

Further, the near infrared erasable toner of the present invention includes
Furthermore, for example, an ultraviolet absorber, a charge control agent, a plasticizer and the like may be appropriately mixed.

Methods for preparing the near infrared erasable toner of the present invention include a solution method and a melting method.

In the solution method, the near-infrared absorbing dye and the binder resin are dissolved and kneaded in an organic solvent, and a decoloring agent, an image stabilizer, wax if necessary, and other additives are mixed and melt-mixed. After removing the organic solvent from the obtained mixture, it is roughly pulverized with, for example, a hammer mill or a cutter mill, and then finely pulverized with, for example, a jet mill to prepare a toner having an average particle size of about 5 to 30 μm. is there.

In the melting method, the near-infrared absorbing dye is heated and melt-kneaded in a binder resin, and a decoloring agent, an image stabilizer, wax if necessary, and other additives are added to the resin, and the mixture is kneaded. After cooling, the toner is prepared by pulverizing in the same manner as the solution method.

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

The near-infrared color erasable toner of the present invention contains an image stabilizer, and as described above, a heat-resistant antioxidant, a metal oxide or a metal soap is used as the image stabilizer. In the meantime, due to the phenolic hydroxyl group of the heat-resistant antioxidant, the basic polar group on the surface of the metal oxide or the anionic carboxyl group of the metal soap, the near-infrared absorption in the near-infrared decolorizable toner is absorbed. The stable dye is stabilized and it has excellent resistance to fading.

Therefore, the near-infrared color erasable toner of the present invention is an image formed by using the toner even when it is heated during the kneading of the raw materials for the toner during the production of the toner. Since it is hard to fade even when it is exposed to natural light or fluorescent light for a long time, it can be printed clearly when riding, including image supports such as copy paper, and erased when getting off and repeated. It can be suitably used for printing usable tickets, coupon tickets, and various pieces of admission tickets.

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

Reference Example 1 The raw materials shown in Tables 1 to 4 were mixed at the blending ratio shown in Examples 1 to 24 or Comparative Example 1 in Table 5 to obtain a mixture. 20 parts of the obtained mixture was stirred at a ratio of 80 parts of 1,1,2,2-tetrachloroethane so as to obtain a uniform composition to obtain a solution.

This solution was used as a blank sample for measuring the absorbance. The compositions of the blank samples used in Examples 1 to 24 and Comparative Example 1 were prepared so as to correspond to Examples 1 to 24 and Comparative Example 1 shown in Table 5, respectively.

Examples 1 to 24 and Comparative Example 1 The raw materials shown in Tables 1 to 4 were mixed at the compounding ratio shown in Table 5 to obtain a mixture. Using the obtained mixture, a mixing chamber temperature of 120 ° C, a mixing chamber filling rate of 70%, and a kneading time of 5 minutes, using a Labo Plastomill: Model 20C200 (chamber volume 60 ml) manufactured by Toyo Seiki Co., Ltd. The mixture was kneaded, and shearing stress was applied to the binding resin.

To the 20 parts of the kneaded mixture obtained next, 1,1,
A toner solution was obtained by stirring at a ratio of 80 parts of 2,2-tetrachloroethane so as to obtain a uniform composition.

The absorbance of the obtained toner solution at a wavelength of 640 nm was measured by using UV / VIS-6 manufactured by JASCO Corporation as an absorptiometer.
It was measured using a 60 spectrophotometer, and the relative absorbance ratio was calculated when the absorbance of the blank sample obtained in Reference Example 1 was 100. The results are shown in Table 5.

Further, the fading property and storage stability of the obtained kneaded product were examined according to the following methods. The results are also shown in Table 5.

(Discoloration) The colors of the obtained kneaded product and the blank sample were visually compared and evaluated based on the following evaluation criteria.

(Evaluation Criteria) A: No change in color is observed in comparison with the blank sample. B: Fading is slightly observed as compared with the blank sample, but there is no practical problem. C: Some fading is observed in comparison with the blank sample, but there is no problem in practical use. D: Discoloration was clearly observed in comparison with the blank sample, which is not suitable for practical use.

(Storage stability) The obtained kneaded product was placed in a glass transparent container and stored at room temperature for 10 days in a laboratory capable of illuminating ordinary natural light. Then, the color of the kneaded product and the blank sample was measured. Visually contrast the above "fading"
It evaluated based on the evaluation standard of. The results are shown in Table 5.

[0063]

[Table 1]

[0064]

[Table 2]

[0065]

[Table 3]

[0066]

[Table 4]

[0067]

[Table 5]

From the results shown in Table 5, when the metal oxide was blended as the image stabilizer as in Examples 1 to 24, there was almost no fading as seen in Comparative Example 1, and the storage was good. It can be seen that a toner having excellent stability can be obtained.

Next, after removing the solvent from the kneaded materials obtained in Examples 1 to 24 and pulverizing with a jet mill, toner particles having an average particle diameter of about 12 μm were obtained using an air classifier. On the other hand, 0.3 wt% of R-972 (manufactured by Nippon Aerosil Co., Ltd., trade name) was added as silica and mixed with a Henschel mixer to obtain a toner.

The decoloring property of the obtained toner is converted into a near-infrared ray by an aluminum coat type halogen lamp (2 W / cm ² ) on a developed image formed by copying the toner on a copy sheet.
I confirmed by irradiating from a distance of 30 cm for 1 hour,
It was confirmed that all of the products obtained in the respective examples had excellent decoloring properties and were practical.

Examples 25 to 29 and Comparative Example 2 Toner solutions were obtained in the same manner as in Example 1 except that the raw materials shown in Tables 1 to 4 were mixed in the proportions shown in Table 6.

The absorbance ratio, the color fading property and the storage stability of the obtained toner solution were examined in the same manner as in Example 1.

Further, the obtained toner solution was applied onto a white copy paper with a brush so that the thickness after drying was about 20 to 25 μm, and after drying, the dichroic halogen lamp (2 W / cm ² ) Was irradiated for 1 hour from a distance of 30 cm to erase the color.

Then, the residual shadow of the toner on the copy paper was visually examined for transparency and gloss. The results are shown in Table 6.

[0075]

[Table 6]

From the results shown in Table 6, in Examples 25 to 29 in which the metal oxide was blended as the image stabilizer, as is clear from the comparison with Comparative Example 2 in which the metal oxide was not blended,
It can be seen that when the gloss decreases and approaches the gloss of copy paper, especially when the blending amount is increased, the toner trace after erasing changes from translucent to opaque and approaches the color of copy paper even more. ..

Examples 30 to 41 and Comparative Examples 3 to 4 The raw materials shown in Tables 1 to 4 were weighed in proportions shown in Table 7 so that the total amount would be 800 g. Next, all the raw materials are put into a pressure type kneader with an effective capacity of 2 liters, the kneader is heated, the kneading temperature of the raw materials is adjusted to 130 ° C., and the mixture is kneaded for 15 minutes. And solidified.

The solidified product thus obtained was crushed to a particle size of about 1 mm using a cutter mill to obtain a toner coarse powder.

The physical properties of the obtained toner coarse powder were examined for thermal fading characteristics and light stability according to the following methods. The results are shown in Table 7.

(Thermal fading characteristic) Since the thermal fading characteristic of the toner coarse powder cannot be examined in a pulverized state, the obtained toner coarse powder is thickened with a hydraulic press at a pressure of 700 kg · f / cm ^2. It was molded into a 2 mm molded product. Using a Macbeth densitometer, the reflection density of the molded product was measured as a thermal fading property. The higher the value, the smaller the thermal fading property.

(Light stability) After the molded product was left under a fluorescent lamp of 1500 lux for 48 hours, the reflection density was measured in the same manner as the thermal fading property, and the formula: (light stability) = (reflection after standing) The light stability was determined according to (density / reflection density before standing) × 100. The higher the value, the greater the photostability.

[0082]

[Table 7]

From the results shown in Table 7, when metal soap was used as the image stabilizer as in Examples 30 to 41, as shown in Comparative Examples 3 to 4, when the raw materials for toner were kneaded. It can be seen that there is almost no discoloration due to heating and the light stability is excellent.

Examples 42 to 44 and Comparative Example 5 The raw materials shown in Tables 1 to 4 were weighed at the blending ratio shown in Examples 42 to 44 or Comparative Example 5 in Table 8 so that the total amount was 5150 to 5200 g. Next, all the raw materials were put into a mixer with an effective capacity of 20 liters, and the contents were mixed for 5 minutes while adjusting the temperature of the raw materials so that the kneading temperature was 25 to 40 ° C. The mixture was kneaded using a co-rotating extruder and cooled to obtain a solidified product. This solidified product was molded into a molded product having a thickness of 2 mm at a pressure of 700 kg · f / cm ² by using a hydraulic press to obtain a sample.

As the physical properties of the obtained sample, image stability 1 to 4 was examined according to the following methods. The results are shown in Table 8.

(Image stability 1) The reflection density of the molded product was measured using a Macbeth densitometer before standing under a fluorescent lamp of 1500 lux (0 minutes) and after standing for 120 minutes. The smaller the difference between before and after the fluorescent lamp irradiation, the better the image stability, and the larger the absolute value, the higher the anti-fading property.

(Image stability 2) manufactured by Nippon Denshoku Industries Co., Ltd.
Z-Σ90 COLOR MEASURING SYSTEM
Using EM, the surface color of the molded product was measured before standing under a fluorescent lamp of 1500 lux (0 minutes) and after standing for 120 minutes. a. b. The value of L on the color solid scale is shown. A larger L value indicates brighter, and a smaller L value indicates darker. In addition, a small change in L value indicates high anti-fading property.

(Image stability 3) Similar to the image stability 2,
The surface color of the molded product was measured before leaving it under a fluorescent lamp of 1500 lux (0 minute) and after leaving for 120 minutes, and the image stability was determined to be L. a. b. The value of a on the color three-dimensional scale is shown. It is shown that the smaller the a value is, the stronger the green is, and the larger the a value is, the stronger the red is. A small change in the a value indicates high anti-fading property.

(Image stability 4) Similar to the image stability 2,
The surface color of the molded product was measured before leaving it under a fluorescent lamp of 1500 lux (0 minutes) and after leaving for 120 minutes, and the image stability was evaluated as L. a. b. The value of b on the color solid scale is shown. It is shown that the smaller the b value, the stronger the blue color, and the larger the b value, the stronger the yellow color. A small change in b value indicates high anti-fading property.

[0090]

[Table 8]

From the results shown in Table 8, when metal soap was used as the image stabilizer as in Examples 42 to 44,
It is understood that the image stability is superior to that of Comparative Example 5.

Examples 45 to 55 and Comparative Examples 6 to 9 The raw materials shown in Tables 1 to 4 were blended in the blending ratios shown in Table 9 and mixed to give a uniform composition to obtain a mixture.

Next, 20 parts of the obtained mixture and 80 parts of 1,1,2,2-tetrachloroethane were mixed, and the mixture was sufficiently dissolved and dispersed to obtain a toner solution.

The obtained toner solution was applied to a white copy paper in a layered manner by brushing so that the thickness of the toner layer after drying was about 20 to 30 μm, and the solvent was volatilized and removed to obtain a sample.

The light resistance A of the obtained sample was examined by the following method. The results are shown in Table 9.

(Light resistance A) The sample was allowed to stand for 10 days at room temperature in a shaded room where direct sunlight enters through a window glass in fine weather, and the discoloration of the sample was compared with that before natural light irradiation. And evaluated based on the following evaluation criteria.

(Evaluation Criteria) A: Discoloration of the sample is not recognized. B: A slight discoloration of the sample is recognized. C: Discoloration of the sample is slightly recognized. D: Discoloration of the sample is clearly recognized.

[0098]

[Table 9]

From the results shown in Table 9, it can be seen that the toners obtained in Examples 45 to 55 in which the heat-resistant antioxidant was blended as the image stabilizer were all excellent in light resistance. When the decoloring properties of the toners obtained in Examples 45 to 55 by near-infrared irradiation were examined, none of the toners obtained in any of the examples contained a heat-resistant antiaging agent as an image stabilizer. It was confirmed that there was no inferiority to the products (Comparative Examples 6 to 9) and that they had a decoloring property that was satisfactory in practical use.

Examples 56 to 65 and Comparative Examples 10 to 12 Toner solutions were prepared in the same manner as in Examples 45 to 55 and Comparative Examples 6 to 9 by mixing the raw materials shown in Tables 1 to 4 in the compounding ratio shown in Table 10. I got it.

Then, Examples 45 to 55 and Comparative Examples 6 to 9
A sample was prepared in the same manner as above, and the light resistance B as a physical property of the obtained sample was examined according to the following method. The results are shown in Table 10.

(Light resistance B) After the sample was left under a fluorescent lamp of 1500 lux for 1 week, the reflection densities of the sample before and after being left were measured by using a Macbeth densitometer, and the formula: ) = (Reflection density after leaving / reflection density before leaving) × 100, the rate of change in reflection density was calculated and evaluated based on the following evaluation criteria.

(Evaluation Criteria) A: Reflection density change rate of 80% or more (excellent light resistance) B: Reflection density change rate of 60% or more and less than 80% (excellent light resistance) C: Reflection density change rate of 40% or more and less than 60% (normal light resistance) D: Reflection density change rate of less than 40% (light resistance is low)

[0104]

[Table 10]

From the results shown in Table 10, it is understood that the toners obtained in Examples 56 to 65 in which the heat-resistant antiaging agent was blended as the image stabilizer were all excellent in light resistance. When the decoloring properties of the toners obtained in Examples 56 to 65 by near infrared rays were examined, those obtained in any of the examples did not contain a heat resistant anti-aging agent as an image stabilizer. It was confirmed that there was no inferior comparison with (Comparative Examples 10 to 12) and that it had a practically satisfactory decoloring property.

[0106]

The near-infrared color erasable toner of the present invention contains a heat-resistant antiaging agent, a metal oxide or a metal soap as an image stabilizer, and is mixed during the kneading of raw materials for the toner during the production of the toner. Decoloration, fading, discoloration, etc. even when the toner is heated, or when the toner is stored or when an image formed by using the toner is irradiated with natural light or fluorescent light. There is almost no occurrence of, and the storage stability is excellent.

The near infrared erasable toner of the present invention is
For example, after applying it on an image support such as copy paper,
When the color is erased by irradiating with near infrared rays, the gloss of the toner trace on the image support can be eliminated, and the gloss of the toner trace can be brought closer to the gloss of the image support.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication 368 (72) Inventor Toshio Kaji 3-2-15 Meiwatsu, Hyogo-ku, Kobe-shi, Hyogo Bando Chemical Co., Ltd. In-house (72) Inventor Takayuki Yoshida 3-2-15 Meiwa-dori, Hyogo-ku, Kobe City, Hyogo Bando Kagaku Co., Ltd. (72) Inventor Kiyotaka Yamaguchi 3-2-1-15 Meiwa-dori, Hyogo-ku, Kobe, Hyogo Bando Inside Chemicals Co., Ltd. (72) Inventor Yuki Abe 3-2-15 Meiwadori, Hyogo-ku, Kobe, Hyogo Prefecture

Claims (10)

[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 ^-, Y is near-infrared absorbing dye and represented by the general formula shows a cation having an absorption property in a near infrared region) (I
I): [Chemical 2] (Wherein 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 the same as described above) At least one selected near-infrared absorbing dye and the general formula (III): (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 ^At least one of ⁷ and 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, alkyl group, aryl group, allyl group, aralkyl group, alkenyl group, alkynyl group, heterocyclic group, substituted alkyl group, substituted aryl group, substituted An allergic group, a substituted aralkyl group, a substituted alkenyl group, or a substituted alkynyl group), which is a decolorizable toner containing an image decoloring agent, characterized by containing an image stabilizer in a binder resin. Near infrared erasable toner. 2. The near-infrared decolorizable type according to claim 1, wherein the binder resin contains a resin having at least one functional group selected from a hydroxyl group, a cyano group, a carbonyl group, a carboxyl group and a ketone group. toner. 3. The binding resin is a polyester resin, an epoxy resin, a (meth) acrylic resin, a polyurethane resin, a polyacrylonitrile resin, a phenol resin,
The decolorizable toner according to claim 2, which is at least one selected from a styrene-acrylic copolymer and a styrene-acrylonitrile copolymer. 4. The near-infrared color erasable toner according to claim 1, wherein the image stabilizer is a heat resistant antioxidant. 5. The near-infrared decolorizable toner according to claim 4, wherein the heat-resistant antioxidant is at least one of a hydroquinone derivative-based antioxidant and a phenol derivative-based antioxidant. 6. A binder resin containing a heat-resistant anti-aging agent in a blending amount.
The near-infrared color erasable toner according to claim 4, which is 0.05 to 30 parts by weight with respect to 100 parts by weight. 7. The image stabilizer is a metal oxide.
Alternatively, the near-infrared color erasable toner according to 2. 8. The near infrared decolorizable toner according to claim 7, wherein the compounding amount of the metal oxide is 1 to 50 parts by weight with respect to 100 parts by weight of the binder resin. 9. The near infrared erasable toner according to claim 1, wherein the image stabilizer is a metal soap. 10. The near-infrared color erasable toner according to claim 9, wherein the blending amount of the metal soap is 0.05 to 10 parts by weight with respect to 100 parts by weight of the binder resin.