JP2762853B2 - Dry toner, method of manufacturing the same, and decoloring method for reusing transfer material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry toner for an electrostatic image used for developing an electrostatic latent image in electrophotography and electrostatic recording.

[0002]

2. Description of the Related Art In recent years, the problem of waste and the effective use of limited resources have been demanded. In particular, paper, dust, and the like discharged from the office have been regarded as problems from the above viewpoint, and copy paper is one of them. Therefore, paper is being recycled, but it has various problems such as high cost of recycling, imbalance between supply and demand, and confidentiality. Is the actual situation. Recently, for the purpose of reusing copy paper, printing was performed on paper using a toner containing photochromic dye and ammonium salt of organic boron as essential components, and when storage of the paper became unnecessary, near-infrared light was irradiated. A method of decoloring the print by applying the method is reported in the Functional Dye Subcommittee Material No. 17.
This technique can be said to be a very interesting technique because it can be easily reproduced in an office in terms of reusing copy paper. However, this method has some problems, and the following problems are pointed out. First, since the color is erased by near-infrared light, storage stability is poor. Further, since the colorant of the toner is limited to a photochromic dye (cyanine dye), printing can be performed only in cyan. further,
Polymer matrix of main component of toner (in binder resin)
In order to generate radicals by irradiating near-infrared light in the inside and decolorize due to structural change, the decoloring speed is slow. on the other hand,
JP-A-62-14163, JP-A-62-67560, JP-A-1-102481 and JP-A-2-71277 report electrophotographic toners that change color by heat. However, these are used for the purpose of preventing re-copying or for multicolor printing, and irreversible erasing of the printing is impossible. Therefore, none of them has been sufficiently satisfactory for the purpose of reusing paper.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances of the prior art. In other words, an object of the present invention is to make it possible to sufficiently read a print on a transfer material and, when storage of the transfer material becomes unnecessary, easily erase the color of the print and reuse the transfer material. It is intended to provide a possible dry toner and a method for producing the same. Another object of the present invention is to provide a dry toner having little dependency on charging temperature and humidity.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a method of recycling a transfer material, and have found that at least an electron-donating color-forming organic compound, an electron-accepting compound, and a contact of these compounds. A dry toner containing a polymer and a binder resin, which irreversibly erases a color-fixed image, has little dependency on charging temperature and humidity.A normal copying operation is performed using the dry toner, and the toner is copied once. The inventors have found that the above object can be achieved by applying heat energy equal to or higher than the fixing heat energy at the time of copying when reusing paper or other transfer materials, and completed the present invention.

That is, the present invention provides a) a colorless or pale-colored electron-donating color-forming organic compound, b) an electron-accepting compound, and c) a decolorizing effect on color development by the combination of the above compounds a) and b). And d) a dry toner containing a binder resin as an essential component, and the toner desirably further contains e) a polypropylene wax. The present invention also relates to a step A of melt-kneading and pulverizing the compounds a) and b) and a part of the resin d), and a step B of melt-kneading and pulverizing the polymer c) and the rest of the resin d). , Step A above
And B. The dry toner production method comprises a step C of melt-kneading and pulverizing the pulverized products obtained in B and B, respectively. The present invention further provides a color erasing method for reusing a transfer material for erasing a fixed image by heating a transfer material holding a fixed toner image. The present invention is directed to a decoloring method for reusing a transfer material containing a) to d).

Hereinafter, the present invention will be described in detail. The dry toner of the present invention is present in the vicinity of a dye domain which has been colored by the transfer of electrons between the colorless or light-colored electron-donating color-forming organic compound of component a) and the electron-accepting compound of component b). A polymer obtained by polymerizing at least a nitrogen-containing monomer having a decolorizing effect of component c) which is not in contact with the binder resin of component d). This dry toner is colored at room temperature and can be read in color even after fixing heat energy of the ordinary copying operation level is applied, but when storage of the transfer material is no longer necessary, the thermal energy is higher than the fixing heat energy. By adding, the printed portion is erased or faded to a state close to an unused transfer material, and can be used again for a new copying purpose. As the transfer material, in addition to paper such as copy paper, polypropylene resin,
Examples include synthetic resin paper such as coumarone indene resin and petroleum resin, and semi-synthetic paper such as nitrocellulose. These transfer materials are usually used in the form of a sheet or a film, but may be a flat molded product.

The colorless or light-coloring electron-donating color-forming organic compound of component a) used in the present invention includes, for example, crystal violet lactone, malachite green lactone, crystal violet carbinol, malachite green carbinol, N- ( 2,3-dichlorophenyl) leuco auramine, N-acetyl auramine,
N-phenyl auramine, N-benzoyl auramine,
Rhodamine-β-lactam, N, 3,3-trimethylindolinobenzospiropyran, 3-diethylamino-6
-Methyl-7-chlorofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-xylidinofluoran, 3-
Examples thereof include diethylamino-7-methoxyfluoran, 3-diethylamino-6-benzyloxyfluoran, and 1,2-benz-6-diethylaminofluoran.

Examples of the electron-accepting compound of component b) include nonylphenol, dodecylphenol, styrenated phenol, 2,2-methylene-bis- (4-methyl-6-t-butylphenol), 2,4,6 -Trichlorophenol, o-phenylphenol, p-phenylphenol, p- (p-chlorophenyl) phenol, o- (o-chlorophenyl) phenol, methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, p-hydroxybenzoate Propyl acid, butyl p-hydroxybenzoate, octyl p-hydroxybenzoate, p
-Dodecyl hydroxybenzoate, bisphenol A,
1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, phenolphthalein, o-cresolphthalein, propyl protocatechuate, butyl protocatechuate, octyl protocatechuate, dodecyl protocatechuate, 2, 3,4-trihydroxyethylbenzene, methyl gallate, ethyl gallate, propyl gallate, butyl gallate, hexyl gallate, octyl gallate, dodecyl gallate, cetyl gallate, stearyl gallate, 2,3,5-tri Hydroxynaphthalene, tannic acid, phenolic resin precondensate, p-ethylphenol, o-ethylphenol, p-cresol, o-cresol, m-cresol, 2,4-xylenol, pyrocatechol, resorcinol, methylcatechol, ethylcatechol Le, propyl catechol, t- butyl catechol, alpha-naphthol, thymol, eugenol, isoeugenol and the like.

[0009] The polymer obtained by polymerizing at least a nitrogen-containing monomer having a decoloring effect on the color development by the combination of the compounds a) and b) of the component c) is, in particular, an addition-polymerizable nitrogen-containing vinyl monomer. Those produced by polymerization are preferably used. Mn and Mw of the obtained polymer are preferably in the range of 2,000 to 40,000 and 50,000 to 1,000,000, respectively. Specific examples of the nitrogen-containing vinyl monomer include 2
-Vinylpyridine, 4-vinylpyridine, 2-vinyl-
6-methylpyridine, 2-vinyl-5-methylpyridine, 4-butenylpyridine, 4-pentenylpyridine,
N-vinyl piperidine, 4-vinyl piperidine, N-vinyl dihydropyridine, N-vinyl pyrrole, 2-vinyl pyrrole, N-vinyl pyrroline, N-vinyl pyrrolidine, 2-vinyl pyrrolidine, N-vinyl-2-pyrrolidone, N -Vinyl-2-piperidone, N-vinylcarbazole, dimethylaminomethyl acrylate, dimethylaminomethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dibutylaminoethyl acrylate, dibutylaminomethyl methacrylate and the like. These can be used alone or 2
More than one type can be used in combination.

As the polymer of component c), other than the above, copolymers of the above-mentioned vinyl monomer containing nitrogen and various monomers can also be used. Examples of other copolymerizable monomers include the following. That is, styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene,
Alkyl styrenes such as butyl styrene, hexyl styrene, heptyl styrene and octyl styrene: halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene and iodostyrene: styrene monomers such as nitrostyrene, acetylstyrene and methoxystyrene Addition-polymerizable unsaturated aliphatic monocarboxylic acids such as α-ethylacrylic acid, crotonic acid, α-methylcrotonic acid, α-ethylcrotonic acid, isocrotonic acid, tiglic acid, ungeric acid: maleic acid, fumaric acid, itacone Acids, citraconic acid, mesaconic acid, glutaconic acid, dihydromutanoic acid, etc .; addition-polymerizable unsaturated aliphatic dicarboxylic acids; the above-mentioned addition-polymerizable unsaturated aliphatic carboxylic acids and alcohols, for example, methyl alcohol, ethyl alcohol, propyl alcohol Unsubstituted alcohols such as coal, butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, dodecyl alcohol, tetradecyl alcohol and hexadecyl alcohol: halogenated alcohols obtained by partially halogenating these unsubstituted alcohols: Alkoxy alcohols such as methoxyethyl alcohol, ethoxyethyl alcohol, ethoxyethoxyethyl alcohol, methoxypropyl alcohol and ethoxypropyl alcohol: Aromatic alcohols such as benzyl alcohol, phenylethyl alcohol and phenylpropyl alcohol: Not available such as allyl alcohol and crotonyl alcohol Esterified product with a saturated alcohol or the like: derived from the above addition-polymerizable unsaturated aliphatic carboxylic acid Amides, nitriles; aliphatic monoolefins such as ethylene, propylene, butene, and isobutylene; vinyl chloride, vinyl bromide, vinyl iodide, 1,2-dichloroethylene, 1,2-dibromoethylene, 1,2-diiodoethylene, Halogenated aliphatic olefins such as isopropenyl chloride, isopropenyl bromide, allyl chloride, allyl bromide, vinylidene chloride, vinyl fluoride, and vinylidene fluoride; 1,3-butadiene;
1,3-pentadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2,4-
Conjugated diene aliphatic diolefins such as hexadiene and 3-methyl-2,4-hexadiene; These can be used alone or in combination of two or more. In the case of a copolymer, the content of the nitrogen-containing monomer is preferably 5% by weight or more.

Examples of the binder resin of the component d) used in the dry toner of the present invention include commonly used styrene resins, polyester resins, epoxy resins, polyamide resins, polyurethane resins and the like. These can be used alone or in combination of two or more.

The dry toner of the present invention exhibits good characteristics as a developer when used as a two-component developer in combination with carrier particles or as a one-component developer without using carrier particles. When a dry toner is used as a magnetic toner, a magnetic powder such as a metal such as iron, cobalt, or nickel, an alloy thereof, or a metal oxide is added to a binder resin. Also, if necessary, surfactants, quaternary ammonium salts, charge controlling agents such as gold-containing dyes having an organic complex structure, plasticizers, particulate or fibrous organic and inorganic fillers, foaming agents, antioxidants, etc. May be included.
The dry toner of the present invention is also intended to improve the fluidity of the developer, storage stability, and the like, or to prevent toner filming on a photosensitive material, and to improve the cleaning property of the toner. Other external additives may be added. Examples of these external additives include long-chain fatty acids such as stearic acid, esters, amides, metal salts, molybdenum disulfide, carbon black, graphite, fluorinated graphite, silicon carbide, boron nitride, silica, aluminum oxide, and dioxide. Examples include fine powders such as titanium, tin oxide, and zinc oxide, fine powders such as a fluororesin, conductive fine powders, polycyclic aromatic compounds, crosslinked and non-crosslinked resin fine powders, and the like.

It is also effective to use various waxes in combination with the toner binder resin. Examples of wax include polyethylene wax, polypropylene wax,
Paraffin wax, montan wax, microcrystalline wax, carnauba wax, beeswax, hollow, candelilla wax, ceresin and the like,
A combination of polypropylene wax is preferred. In addition, various natural and synthetic ester waxes can be used. Further, a leuco compound, a color developer, and a colorant may be dispersed in wax, and these may be used as a colorant for the toner.

As a method for producing the dry toner of the present invention, an ordinary toner production method can be used. Specific examples include a method of pulverizing raw materials after melt-kneading, a spray drying method, a direct polymerization method, and various microencapsulation methods. In the production of a dry toner, it is important to mix it with the binder resin d) so that the colored product of the combination of the compounds a) and b) and the polymer c) do not contact as much as possible. For example, in the case of producing a dry toner by a method of pulverizing after melt-kneading, compounds a) and b) and polymer c) are melt-kneaded and pulverized together with binder resin d) in separate steps, and then pulverized. A method comprising a step of combining the pulverized materials obtained in each step, melt-kneading and pulverizing again is recommended. In these steps, waxes such as polypropylene wax may or may not be added, and various additives as described above may be added as necessary.

When the transfer material holding the fixed toner image is heated to erase the color of the fixed image, it is necessary to apply heat energy equal to or higher than the fixing heat energy at the time of copying. The thermal energy is mainly related to the operating temperature and the transfer speed of the transfer material during fixing and decoloring. In general, the faster the transfer speed of the transfer material, the better. Is desirable. Usually, the conveyance speed at the time of decoloring is appropriately in the range of about 10 to 100 mm / sec, and the operation temperature at that time is about 150 to 300 ° C, preferably about 200 to 250 ° C.

[0016]

The present invention will be described below in detail with reference to examples. Example 1 Crystal violet lactone 100 g Bisphenol A 200 g Partially crosslinked epoxy resin 800 g Polypropylene wax 30 g After melt-mixing the above composition with a Banbury mixer,
It was cooled and coarsely pulverized to 1 mm or less. Styrene resin 450 g Polypropylene wax 10 g Styrene (80 wt%)-dimethylaminoethyl methacrylate (20 wt%) (Mn: 6,500, Mw: 200,000) 450 g After blending the above components with a Banbury mixer,
It was cooled and coarsely pulverized to 1 mm or less. This coarsely crushed material 500
g, and 500 g of the above coarsely pulverized material were mixed with a Henschel mixer, and then melt-mixed with an extruder. Thereafter, the molten mixture was pulverized and classified, and 1% by weight of hydrophobic silica was added and mixed with a Henschel mixer to obtain a toner of the present invention.

Example 2 A toner of the present invention was obtained in the same manner as in Example 1, except that crystal violet lactone was replaced with 3-diethylamino-6-methyl-7-anilinofluoran.

Comparative Example A control toner was obtained in the same manner as in Example 1, except that the styrene-dimethylaminoethyl methacrylate copolymer was changed to methylpiperazine.

Evaluation Test Three types of developers were prepared by mixing 50 g of the toners obtained in Examples 1 and 2 and Comparative Example with 950 g of a ferrite carrier coated with a coating material containing polymethyl methacrylate as a main component. . These developers were used as FX-5039
Using a copier (manufactured by Fuji Xerox Co., Ltd.), a fixing heat roll temperature of 180 ° C. and a paper conveying speed of 200 mm / sec.
Under the above conditions to obtain a copy paper on which a toner image was formed. The obtained copy paper was subjected to a heat treatment by an external fixing device adjusted to a decoloring heat roll temperature of 220 ° C. and a paper conveyance speed of 20 mm / sec. The results are shown in Table 1 below. The image density was measured using a Macbeth densitometer. The initial image density was obtained by copying using a patch document of 1.0 Gray.

[0020]

[Table 1]

[0021]

As is clear from Table 1, in a toner not containing a polymer obtained by polymerizing at least a nitrogen-containing monomer having a decolorizing effect of the component c), the charge is more than doubled between summer and winter. And a stable copy cannot be obtained. On the other hand, in the toner of the present invention, at the time of ordinary copying, an easily readable image density can be obtained by a combination of the electron-donating color-forming organic compound of the component a) and the electron-accepting compound of the component b). After copying, the toner contains a polymer having a decolorizing effect of component c) with respect to the color development of components a) and b). It is possible to erase another original as a transfer material for copying until the original can be copied. In addition, since the polymer of the component c) is a polymer obtained by polymerizing a nitrogen-containing monomer having low temperature / humidity dependency, the charging temperature / humidity dependency is also good.

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G03G 9/08 CA (STN)

Claims (4)

(57) [Claims] 1. a) a colorless or pale-colored electron-donating color-forming organic compound b) an electron-accepting compound c) at least a nitrogen-containing monomer having a decoloring effect on the color development by the combination of the compounds a) and b) D) a binder comprising: a) a binder resin; and a) to d) as essential components. 2. The dry toner according to claim 1, further comprising e) a polypropylene wax as an essential component. 3. A. a) A step of melt-kneading and pulverizing a) a colorless or pale-colored electron-donating color-forming organic compound and b) an electron-accepting compound and d) a part of a binder resin. c) a step of melt-kneading and pulverizing a polymer obtained by polymerizing at least a nitrogen-containing monomer having a decoloring effect on the color formation by the combination of the compounds a) and b) and d) the remaining binder resin; . A step of melt-kneading and pulverizing the pulverized product of step A and step B. A method for producing a dry toner comprising the above steps. 4. In a decoloring method for reusing a transfer material for heating a transfer material holding a fixed toner image and decoloring the fixed image, at least toner forming a toner image is used. A decoloring method for reusing a transfer material, characterized by containing the essential components described above.