JPH0659500A - Method for discoloring picture formed by discolorable colorant and discoloring device used therefor - Google Patents

Abstract

PURPOSE:To rapidly discolor the picture formed on a picture substrate by a discolorable colorant such as toner and ink by using this device. CONSTITUTION:A picture formed on a substrate by a discolorable colorant obtained by incorporating a near IR absorbing dye into a binder resin is treated with oil, then irradiated with near IR and discolored by using the discoloring device. The device is provided with an oil depositing material for treating the picture with oil and a near IR irradiation light source for irradiating the picture with near IR.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for erasing an image formed with a erasable colorant and a erasing apparatus used for the method. More specifically, the present invention relates to a method capable of rapidly decoloring an image formed with a decolorizable colorant such as toner or ink formed on an image support, and a decoloring apparatus which can be suitably used for the method.

[0002]

2. Description of the Related Art In recent years, the reuse and recycling of used paper has been reviewed for the purpose of nature protection, particularly forest resource protection and waste reduction in urban areas. As part of this, the reuse of used copy paper, printed matter, facsimile paper, etc. that has become unnecessary in the office of a company 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 above toner, an image recorded on a copy sheet can be erased by only irradiating near infrared rays, and electrostatic copying can be performed again after erasing. Therefore, the copy paper can be reused, and when the used copy paper is discarded,
Since recorded images can be erased by irradiation of near-infrared rays, it is possible to prevent confidential information from leaking to the outside, and at the same time, it is possible to collect and recycle the copy paper, which is a great advantage. There is.

However, the erasing speed is low only by irradiating an image recorded on a copy sheet with near infrared rays, and for example, an image on the entire copy sheet having a size of No. 4 in the Japanese Industrial Standard A is deleted. For example, at least several tens of seconds is required for each copy sheet, in other words, there is a drawback that images or the like can be erased only for several sheets per minute.

Therefore, the inventors of the present invention have conducted extensive studies in order to eliminate such drawbacks, and as a result, after treating the image formed on the image support with the toner with silicone oil, the near infrared rays are applied to the image. The time required for erasing an image or the like can be shortened by irradiating the surface of the object, and the time required for erasing the image can be further shortened when the image is treated with silicone oil while being heated. It has been found that the time required for erasing an image and the like can be further shortened when the silicone oil contains a decoloring agent, and the present invention has been completed.

[0008]

That is, according to the present invention, (A) an image formed on an image support is treated with an oil by a decolorizable colorant comprising a binder resin containing a near-infrared absorbing dye. Then, a near-infrared ray is applied to the image to form an image-erasable colorant, which is a method for decoloring an image, and (B) a decolorizing property obtained by incorporating a near-infrared absorbing dye into a binder resin. The present invention relates to an erasing device comprising an oil-adhering material for treating an image formed on a image support with a colorant with oil and a near-infrared irradiation light source for irradiating the image with near-infrared light.

[0009]

Functions and Examples According to the method for erasing an image formed with the erasable colorant of the present invention, as described above, the erasable colorant obtained by incorporating the near-infrared absorbing dye into the binder resin is used. After the image formed on the image support is treated with oil, it can be erased by irradiating the image with near infrared rays.

The reason why the erasing speed is improved by the erasing method of the present invention is not clear, but probably oil is impregnated in the image formed on the image support and the image is irradiated with near infrared rays. It is presumed that this is because the oil serves as a medium for introducing near-infrared rays into the inner layer portion of the image and at the same time enhances the fluidity of the near-infrared absorbing dye or decoloring agent contained in the image.

Further, when the image formed on the image support is heated, the fluidity of the binder resin and the decolorizing agent contained in the decolorizable toner is improved, so that the decoloring speed is improved. It is estimated to improve.

When the oil also contains a decolorizing agent, the image formed on the image support and the decolorizing agent contained in the oil come into contact with each other, and the decoloring speed is further improved. It is estimated to improve.

The decolorizable colorant used in the decolorizing method of the present invention contains a near infrared absorbing dye as an essential component, and the other components are appropriately adjusted according to the type of the decolorizable colorant. To be done.

Examples of the near-infrared absorbing dyes include those represented by the general formula (I):

[0015]

[Chemical 1]

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

[0017]

[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 defined above) and the like. Is used.

In the general formula (I), 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 ⁻ , ^{_{FCH 2 SO 3 -, F 2}} CHSO 3 -, F 3 CS
^{_{O 3 -, ClCH 2 SO 3}} -, Cl 2 CHSO 3 -, C
l ₃ CSO ₃ ⁻ , CH ₃ OCH ₂ SO ₃ ⁻ , (CH ₃ )
₂ NCH ₂ SO ₃ ⁻ and other substituted methylsulfonate ions, C ₆ H ₅ SO ₃ ⁻ and other phenylsulfonate ions, CH ₃ C ₆ H ₄ SO ₃ ⁻ , (CH ₃ ) ₂ C ₆ H ₃ S
^{_{O 3 -, (CH 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 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 F 5 SO
^{_{3 -, (CH 3) 2}} NC 6 H 4 SO 3 - and the like substituted phenyl sulfonate ion such.

In the general formula (II), R ¹ , R ² ,
Specific examples of R ³ and R ⁴ include, for example, a hydrogen atom,
Alkyl group, aryl group, allyl group, aralkyl group, alkenyl group, alkynyl group, silyl group, heterocyclic group, substituted alkyl group, substituted aryl group, substituted allyl group, substituted aralkyl group, substituted alkenyl group, substituted alkynyl group, substituted Examples include silyl groups. 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, chlorophenyl group, diethylaminophenyl group, vinyl group, allyl group, triphenylsilyl group, dimethylphenylsilyl group, dibutylphenylsilyl group, trimethylsilyl group, piperidyl group, thienyl Group, furyl group and the like. 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. Examples thereof include alkyl groups having 4 to 12 carbon atoms such as groups, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group and n-dodecyl group.

Further, in the general formula (I) or the general formula (II), preferred as Y ⁺ are, for example, cyanine, triarylmethane, aminium, diimmonium, thiazine, xanthene and oxazine which have absorption characteristics in the near infrared region. , Styryl, pyrylium-based cationic dyes and the like. As a typical example of such Y ⁺ , for example,

[0022]

[Chemical 3]

[0023]

[Chemical 4]

And the like.

The amount of the near-infrared absorptive dye blended cannot be unconditionally determined because it varies depending on the type of the decolorizable colorant. Therefore, as will be described later, it is usually determined according to the type of the decolorizable colorant. Adjusted.

The decolorizable colorant may be preliminarily blended with the decolorizing agent, or may be blended only with the oil described below without blending the decolorizing agent. Good. When the decoloring colorant is blended with the decoloring agent in advance, the decoloring speed at the time of decoloring can be increased, but the light resistance of the decoloring colorant tends to be lowered.

Examples of the decoloring agent include those represented by the general formula (II
I):

[0028]

[Chemical 5]

(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 , 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-butyltrianisylboron, 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, tetramethylammonium n-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 blending amount of the decoloring agent cannot be unconditionally determined because it varies depending on the kind of the near-infrared absorbing dye, but it is usually 100 parts by weight of the near-infrared absorbing dye (part by weight, hereinafter the same). On the other hand, 0.1 to 2500 parts, preferably 0.
It is selected from the range of 5 to 1000 copies. When the blending amount of the decoloring agent is less than the above range, sufficient decoloring property is not imparted, and when it is more than the above range,
The underprint printed using the obtained recording material tends to have poor light resistance and is likely to undergo discoloration or fading.

Examples of the decolorizable colorant include toner, ink, ink ribbon, pressure-sensitive transfer sheet, and heat-sensitive transfer sheet, but the present invention is not limited to these examples. Typical examples of the decolorizable colorant include toners, inks, and pressure-sensitive transfer sheets among the above-mentioned ones.

The toner is a powdery decolorizable colorant obtained by pulverizing a binder resin containing a near-infrared absorbing dye and a decoloring agent.

Examples of the binder resin include polystyrene resins represented by polystyrene and the like, polyester resins represented by polyester and unsaturated polyester, epoxy resins, and (meth) acryl represented by polymethylmethacrylate. Examples of the resin include a resin, a silicone resin, a fluororesin, a polyamide resin, a polyvinyl alcohol resin, a polyurethane resin, a polyolefin resin, a polyvinyl butyral resin, a phenol formaldehyde resin, and a rosin-modified phenol formaldehyde resin. It is not limited to the examples. These binder resins are usually used alone or in combination of two or more.

In the present invention, the binder resin may be blended with wax such as polyolefin wax and paraffin wax, if necessary. The amount of such a wax to be added is such that the binder resin is used in order to sufficiently bring out the effect of adding 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, but if the amount of the wax is too large, film formation on the photoreceptor that forms an electrical latent image occurs. Since there is a tendency, the amount is preferably 20 parts or less, and more preferably 10 parts or less, based on 100 parts of the binder resin.

The amount of the near-infrared absorbing dye blended is 0.01 to 30 parts, preferably 0.5 to 100 parts by weight of the binder resin.
~ 20 copies. When the blending amount of such a near-infrared absorbing dye is less than the above range, sufficient coloring property is not imparted, and when it is more than the above range, the triboelectric charge amount of the obtained toner is adversely affected. May be given.

The toner may be, for example, a charge control agent,
Additives such as a plasticizer, a heat resistant anti-aging agent, and an ultraviolet absorber may be appropriately mixed.

The toner manufacturing method includes a solution method and a melting method.

The solution method means that the near-infrared absorbing dye, the decoloring agent and the binder resin are dissolved and mixed in an organic solvent, and if necessary, additives are added and dissolved and mixed. In this method, the solvent is removed, coarsely pulverized with, for example, a hammer mill or cutter mill, and then finely pulverized with, for example, a jet mill to produce a toner.

In the melting method, the near-infrared absorbing dye and the decoloring agent are heated and melt-kneaded in a binder resin, and if necessary, additives are added, and after kneading and cooling, the solution method is used. It is a method for producing a toner by finely pulverizing in the same manner as in.

The particle size range of the toner is usually 30 μm.
Hereinafter, it is preferable to adjust the thickness to about 3 to 25 μm. The average particle diameter of the toner is usually 20 μm or less, preferably about 7 to 15 μm. If the average particle size exceeds 20 μm, it tends to be difficult to reproduce an image faithful to the original image.

A typical example of the method for forming an image or the like on an image support by using a toner as an erasable colorant is, for example, a method for forming a predetermined image by using a so-called electrostatic image developing copying machine. However, the present invention is not limited to such examples.

The method of forming an image on an image support using the toner is particularly effective when it is necessary to accurately copy a predetermined image in a small amount.

Examples of the ink include printing inks, inks for water-based pens, inks for felt pens, and the like, but the present invention is not limited to these examples. As typical ones of the ink,
Among the above-mentioned ones, printing ink can be mentioned.

The printing ink can be obtained by mixing a near-infrared absorbing dye and a decoloring agent with a vehicle for fixing the ink on the surface of a paper base material which is an object to be printed.

Examples of the vehicle include a drying oil which dries in a relatively short time when left in the air, a drying property, a luster,
It is composed of a resin for improving the transferability and a solvent which gives necessary viscosity and fluidity.

Examples of the drying oil include linseed oil,
Examples include cinnamon oil, soybean oil, and castor oil.

Examples of the resin include natural resins such as rosin and shellac; natural resin derivatives such as cured rosin, rosin ester, maleic acid resin and fumaric acid resin; phenol resin, xylene resin, urea-melamine resin, ketone resin, Synthetic resins such as polyvinyl chloride, vinyl chloride-vinyl acetate resin, butyral resin, styrene-maleic acid resin, chlorinated polypropylene, acrylic resin, polyester, alkyd resin, polyamide, epoxy resin, polyurethane, nitrocellulose, etc. .

Examples of the solvent include aliphatic hydrocarbons such as hexane, heptane and rubber volatile oil; aromatic hydrocarbons such as toluene and xylene; methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, Alcohols such as cyclohexyl alcohol; diethylene glycol,
Glycols such as dipropylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, glycerin; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene Glycol derivatives such as glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate; esters such as ethyl acetate, isopropyl acetate, butyl acetate; acetone, methyl ethyl ketone,
Examples include ketones such as methyl isobutyl ketone and cyclohexanone.

The blending amounts of the drying oil, resin and solvent are as follows:
It cannot be determined unconditionally because it depends on the type of printing ink, but usually the vehicle contains 10-30% by weight of drying oil, 20-40% by weight of resin, and 30-60% by weight of solvent. Adjusted to.

If desired, the vehicle may contain a plasticizer, a filler, an ultraviolet absorber, a wax, and the like.

The compounding amount of the near-infrared absorbing dye is usually 0.01 to 90 parts per 100 parts of the vehicle, especially 0.5 to
Adjusted within 20 copies. When the compounding amount is less than the above range, the coloring property becomes insufficient, and when it is more than the above range, the time required for decoloring becomes long.

As a method for forming an image or the like on an image support using a printing ink, for example, offset printing,
Examples of the method include letterpress printing, gravure printing, stencil printing, flexographic printing, metal printing, plastic printing, glass printing, special printing such as transfer paper printing, and electronic printing using a printer such as an impact printer.

The method of printing using the printing ink is
This is particularly effective when a large number of images having the same shape formed on an image support need to be produced.

The pressure-sensitive transfer sheet is, for example, a resin film such as polyethylene terephthalate prepared by blending a binder such as paraffin wax with a near-infrared absorbing dye and a decoloring agent, and further blending a softening agent such as xylene resin. It is applied on the surface of paraffin paper. When such a pressure-sensitive transfer sheet is used, it is not possible to form a large number of images of the same shape at one time, but when forming a small number of rough images, a large-scale printing machine or copying machine is required. It is simple because it is unnecessary.

When the pressure-sensitive transfer sheet is used, an image having a predetermined shape is formed by superposing the pressure-sensitive transfer sheet on the image support, which is an object to be copied, and pressing and printing.

The image support referred to in the present specification refers to a base material capable of fixing an image formed by a decolorizable colorant, and specific examples of such an image support include, for example, pulp, natural or Examples include materials obtained by processing materials such as synthetic fibers, synthetic resins, rubber, and metals into paper, film, woven cloth, non-woven cloth, sheets, plates, and the like.

The image referred to in the present specification is not particularly limited, but for example, a partially colored or whole surface of the image support such as colored prints, figures and patterns formed on the image support. It is something that is colored.

The method of forming the image is not particularly limited, and examples thereof include a method of fixing the decolorizable toner on the image support using a normal copying machine.

As the copying machine, a copying machine for developing electrostatic image is usually used, and the model of the copying machine is not particularly limited, and various kinds can be used.

Next, the image formed on the image support with the decolorizable toner is treated with oil.

As a method for processing an image with oil,
For example, a method of bringing an oil-adhering material such as a belt, a roller, or a brush to which oil is attached into contact with the image can be used.

FIG. 1 is a schematic explanatory view of a erasing device used in the erasing method of the present invention. The decoloring device 1 includes an oil tank 3 in which an oil 2 for treating an image formed on an image support with oil is injected, and an oil adhering material (felt felt) having one end immersed in the oil 2 in the oil tank 3. ) 4 is provided. The oil attachment material 4 is in contact with the application roller 5 and has a role of attaching the oil 2 to the application roller 5.

The coating roller 5 rotates in the direction of arrow A, and the pressure roller 6 simultaneously rotates in the direction of arrow B.

By inserting the image support in the direction of arrow C so that the formed image is the upper surface, the oil 2 attached to the coating roller 5 is attached on the image.

Here, examples of the oil include silicone oils such as various polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, and modified polysiloxane, and Daifloyl # 1, # 3, # 10. , # 20, # 30 (above, Daikin Industries, Ltd., trade name) and other representative trifluorochloroethylene compounds, Hiluve D550 (Daiichi Kogyo Seiyaku Co., Ltd., trade name), etc. However, the present invention is not limited to these examples.

When the kinematic viscosity of the oil at 25 ° C. is too small, the coating amount on the image surface tends to be extremely small, and when it is too large, the coating amount on the image surface is large. Is usually 10 to 70,000 cSt, especially 30 to 5000.
It is preferably 0 cSt, especially 100 to 30,000 cSt.

When the amount of the oil adhered to the image is too large, it becomes possible to visually recognize that the oil is present on the image surface, and when it is too small, the oil is sufficiently erased. Since it tends to be impossible to reduce the color speed, it is usually preferably 0.01 to 5 g / m ² .

In order to further increase the erasing speed,
It is desirable to add a decolorizing agent to the oil.

Examples of the decoloring agent include those exemplified above, and the amount of the decoloring agent to be blended is 100% with respect to 100 parts of the oil in order to sufficiently exert the effect of increasing the decoloring speed.
It is desirable that the amount is 1 part or more, preferably 5 parts or more, and more preferably 20 parts or more, but if the amount of the decoloring agent is too large, crystals of the decoloring agent will be present. Therefore, it is preferably 300 parts or less, more preferably 20 parts or less.
It is desirable that the content is 0 or less.

When the decoloring agent is blended with the oil, the decoloring agent is crushed in advance by using a wet type crusher such as a co-ball mill, a ball mill or a homogenizer and dispersed in the oil. It is preferable.

It is also preferable to heat the image when the image support is sandwiched between the coating roller 5 and the pressure roller 6. Thus, when the image is heated, the mobility of the binder resin contained in the image is improved and the decoloring agent is melted, so that the decoloring speed is further improved.

From this point of view, the temperature at which the image is heated is preferably a temperature above the softening point of the binder resin, and more preferably above the melting point of the decoloring agent. In the present invention, the melting point of the decolorizing agent is generally 14
Since the temperature is around 0 ° C, the temperature for heating the image is 140
℃ or more, preferably 150 ℃ or more, more preferably 180
It is desirable that the temperature is ℃ or higher.

As a method for heating the image formed on the image support, for example, a heater 7 is provided inside the coating roller 5.
There is a method of heating the image by heating the coating roller 5 by the heater 7 with the heater mounted.
When such a method is adopted, there is an advantage that the image can be simultaneously processed with oil while heating the image.

The image support bearing the image treated with oil is then transported onto the near infrared irradiation plate 8,
Near-infrared rays are irradiated onto the image support from the near-infrared ray irradiation light source 9 on the plate 8.

Examples of the light source 9 include a semiconductor laser, a halogen lamp, and a light emitting diode, but the present invention is not limited to such examples.

The irradiation time of the near infrared rays cannot be unconditionally determined because it varies depending on the type of the light source 9 and the distance from the light source 9 to the image on the plate 8.

The image support irradiated with near-infrared rays is then discharged from the plate 8 by a carry-out roller 11 rotating in the direction of arrow D.
And is carried out of the erasing apparatus 1 via the carry-out roller 10 rotating in the arrow E direction.

Thus, the image on the image support is erased, and the image can be formed on the image support on which the image has been erased again by using the decolorizable colorant. In this case,
Even when the oil contains a decolorizing agent, the image formed by the decolorizing colorant is not adversely affected by the decoloring agent.

Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Production Example 1 As a binder resin, 100 parts by weight of a styrene-butyl acrylate (weight ratio 94: 6) copolymer was used, and the formula:

[0082]

[Chemical 6]

An ink was prepared by mixing 2 parts of the near-infrared absorbing dye represented by the formula, 3 parts of tetrabutylammonium n-butyltriphenylboron as a decoloring agent and 300 parts of dichloromethane as a solvent, and thoroughly stirring them.

The obtained ink was applied onto a recording paper (Fuji Xerox Co., Ltd., No. V602) to a thickness of 20 μm using a bar coater and dried to obtain Sample A.

Production Example 2 As a binder resin, a compound of the formula: 100 parts by weight of a styrene-butyl acrylate (weight ratio of 94: 6) copolymer was used.

[0086]

[Chemical 7]

2 parts of a near infrared absorbing dye represented by: 3 parts of tetrabutylammonium n-butyltriphenylboron as a decoloring agent and Viscole 550 as a wax.
P (manufactured by Sanyo Kasei Co., Ltd., trade name) was mixed at a ratio of 5 parts, and the mixture was kneaded for 5 minutes at 120 ° C. in a pressure mixer and then cooled. Then, the toner was classified by a classifier to obtain a toner having an average particle size of 10 μm.

To 100 parts of the obtained toner, 0.5 part of fine silica powder (R972, manufactured by Nippon Aerosil Co., Ltd.) was added and mixed with a Henschel mixer to obtain a toner mixture.

5 parts of the obtained toner mixture and 95 parts of carrier (FH810 manufactured by Kanto Denka Kogyo Co., Ltd.) were mixed to obtain a developer.

Next, a laser beam printer (KX-P4420, manufactured by Kyushu Matsushita Electric Co., Ltd.) was loaded with the obtained developer, and recording paper (manufactured by Fuji Xerox Co., Ltd., No. 4) was loaded.
The character "TONER" was printed on V602) (the thickness of the toner layer in the printed portion: about 10 μm) to obtain Sample B.

Production Example 3 Styrene-2-ethylhexyl acrylate (weight ratio 92: 8) copolymer 100 was used as the binding resin in Production Example 1.
Part, except that the compounding amount of the near-infrared absorbing dye was changed from 2 parts to 3 parts and no decoloring agent was used.
Sample C was obtained in the same manner as in.

Production Examples 4 to 14 Dimethylpolysiloxane was used as the oil and tetrabutylammonium was used as the decoloring agent at the blending ratios shown in Table 1.
n-Butyltriphenylboron (hereinafter referred to as SE-I), tetrabutylammonium dimethyldiphenylboron (hereinafter referred to as SE-II) or tetrabutylammonium dibutyldiphenylboron (hereinafter referred to as SE-III)
, And then mixed with about 200 ml of zirconium media with an average particle size of 1 mm and filled with 500 ml.
150 ml of the obtained mixture was put into a polypropylene bottle, and crushed at a frequency of 60 Hz and an amplitude of 30 mm for 10 hours, and then zirconium media was removed through a mesh (opening of the sieve: 0.5 mm) to obtain a processing oil. .

[0093]

[Table 1]

Example As the decoloring device, the one shown in FIG. 1 was used.

The treatment oil obtained in Production Examples 4 to 14 was poured into the oil tank 3.

The surface temperature of the coating roller 5 is 120 ° C., 150 ° C.
Or, at 180 ° C., samples A to C were fed into the erasing device 1 with the printing surface facing upward, and the maximum feeding speed of the sample when the color could be completely erased was evaluated as the erasing speed. did.

An aluminum coat type halogen lamp (4 W / cm ² ) was used as the light source 9 and adjusted so that the shortest distance to the image was 20 cm.

The results are shown in Table 2.

[0099]

[Table 2]

As is clear from the comparison between Experimental Example 11 and Comparative Example, it is recognized that when the image formed on the image support is treated with oil, the decoloring speed is improved.

From the results of Experimental Examples 1 to 12, it is understood that the erasing speed can be further increased by increasing the heating temperature during erasing.

Further, from the results of Experimental Examples 5 to 7, it is understood that the decoloring speed can be further increased by increasing the amount of the decolorizing agent blended in the oil.

[0103]

EFFECTS OF THE INVENTION According to the method for erasing an image formed with the erasable colorant of the present invention, the image formed on the image support can be rapidly erased, and therefore the efficiency of the erasing operation is improved. It has the effect of making a significant contribution to improvement.

Further, the erasing apparatus used in the erasing method of the present invention can be erased in a short time by simply inserting the image support for erasing the formed image into the erasing apparatus. In addition, since the image support after being erased can be reused as it is, it greatly contributes to the improvement of efficiency of the erasing work and the reuse of resources.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of a color erasing device of the present invention.

[Explanation of symbols]

 1 Decoloring device 2 Oil 4 Oil adhering material 9 Near infrared irradiation light source

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuuki Abe 3-15, Meiwadori, Hyogo-ku, Kobe-shi, Hyogo Bando Kagaku Co., Ltd. No. 2-15 Bando Kagaku Co., Ltd.

Claims (5)

[Claims] 1. An image formed on an image support with a decolorizable colorant comprising a binding resin containing a near-infrared absorbing dye is treated with oil, and then the image is irradiated with near-infrared rays. A method for erasing an image formed with an erasable colorant, characterized by: 2. The erasing method according to claim 1, wherein the image is treated with oil while heating. 3. The erasing method according to claim 2, wherein the heating temperature for heating the image is a temperature equal to or higher than the melting point of the erasing agent. 4. The decoloring method according to claim 1, 2 or 3, wherein the oil contains a decoloring agent. 5. An oil-adhesive material for treating an image formed on an image support with oil by a decolorizable colorant comprising a binding resin containing a near-infrared absorbing dye, and a near-infrared ray for the image. An erasing device having a light source for irradiating near infrared rays for irradiating.