JP2002278148A - Toner for micr - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner for MICR(magnetic ink character recognition) which has superior rubbing resistance against a magnetic head, causes no read error by developing proper signal intensity, and has small dispersion in signal intensity among manufacture lots, and is free of problems of picture quality such as image density and fogging. SOLUTION: First toner for MICR is characterized by that acicular magnetite is stuck on the surface of toner containing binding resin and granular magnetite. Further, second toner for MICR is characterized by that acicular magnetite and a fluidizing agent are stuck on the toner surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a MICR (Magnetic Ink Char) used for magnetic reading printing in a magnetic one-component developing system printer or copier.
actor Recognition).

[0002]

2. Description of the Related Art In recent years, magnetic ink character recognition (MIC)
It has become very easy to prepare a document capable of R), in particular, a check and a bill by a magnetic one-component developing method using a magnetic toner. MICR is a method in which an image is magnetized and read out by a magnetic head. Usually, an image is created by offset printing or the like using magnetic ink, so that it is not simple. Although a printing method using a two-component developing method has also been put into practical use, it cannot be said that it is simple because the machine becomes larger than a one-component developing method. Although there is a thermal transfer type as a small printing machine, most of the single function machines print only MICR characters. Therefore, there is a demand for a small printer capable of simultaneously printing characters and graphics other than MICR characters. In that respect, the magnetic one-component developing system is compact in size and easy to maintain.
Since printing other than CR characters can be easily performed, applications for MICR have been developed.

It has been attempted to use a magnetic material having a large magnetization itself as the conventional MICR toner, and JP-A-6-282100 and JP-A-7-271085 disclose the use of acicular magnetite. . However, there is a problem that acicular magnetite is easily exposed on the toner surface and is easily rubbed off by rubbing with a magnetic head.
In addition, an appropriate saturation magnetization is required for the magnetic one-component development, but if needle magnetite is contained in an amount required for the development, the signal intensity becomes too high. Further, the use amount of acicular magnetite is limited due to poor dispersibility, and it has been difficult to satisfy both the saturation magnetization required for development and the residual magnetization required for signal intensity. Further, there is a problem that the dispersion state is different for each production lot due to the poor dispersibility, and the dispersion of the signal intensity becomes large. Therefore, even if magnetite of another shape was used in combination, all conditions were not satisfied.

Further, in order to improve the rubbing property, MI
Various waxes can be added to the CR toner,
JP-A-6-282100, JP-A-6-43689,
Although disclosed in Japanese Patent Application Laid-Open No. Hei 7-270855, even if there is no problem as a mere image, there are many cases where a problem occurs in magnetic reading, and it has been difficult to sufficiently satisfy the demand.

[0005] As described above, the conventional MICR toner has excellent rubbing resistance to the magnetic head, an appropriate and small variation in signal intensity between production lots, and an image quality such as image density and fog. Nothing was problematic in this regard.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic head having excellent resistance to rubbing and exhibiting a proper signal strength without causing a reading error, thereby enabling a signal between manufacturing lots to be produced. MIC with little variation in intensity and no problem in image quality such as image density and fog
An object of the present invention is to provide an R toner.

[0007]

SUMMARY OF THE INVENTION A first MICR of the present invention
The toner for MICR is a toner for MICR, wherein at least acicular magnetite is attached to the surface of a toner containing a binder resin and particulate magnetite.
Further, the second MICR toner of the present invention is a MICR toner characterized in that acicular magnetite and a fluidizing agent are attached to the toner surface.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The binder resin of the toner of the present invention includes styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymer and styrene-vinyltoluene copolymer. And a homopolymer of the substituted product thereof and a copolymer thereof;
Copolymer of styrene and acrylate, such as styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-acrylic acid-n-butyl copolymer; styrene-methyl methacrylate copolymer Copolymer of styrene and methacrylate, such as styrene-ethyl methacrylate copolymer and styrene-methacrylic acid-n-butyl copolymer; multi-component copolymer of styrene, acrylate and methacrylate; Other styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile indene copolymer, styrene-maleic acid ester copolymer Of styrene and other vinyl monomers Emissions copolymer; polymethyl methacrylate, polybutyl methacrylate, polyacrylic acid ester resins, polyester resins, polyvinyl acetate, polyamide resins, epoxy resins, polyvinyl butyral resins, polyacrylic acid phenol resins, phenol resins,
Aliphatic or alicyclic hydrocarbon resins, petroleum resins, chlorinated paraffins, polyvinyl chloride, polyvinylidene chloride, and the like can be used alone or in combination. In the present invention, among these, styrene-acrylate copolymer resins and polyester resins are preferably used.

In the present invention, the granular magnetite is required mainly for developability, and the acicular magnetite is mainly required for signal strength. By adhering the acicular magnetite to the surface, it is possible to secure the signal intensity with a small amount and to reduce the variation in the signal intensity between production lots due to poor dispersibility, as compared with the case where the magnetite is contained inside. In the present invention, the particulate magnetite added to the inside of the toner includes irregular, spherical, hexahedral, and octahedral. In this case, the added amount of the particulate magnetite particles is preferably 5.0 to 40% by weight in the toner, and more preferably 10 to 40% by weight.
~ 35% by weight. 4. The content of particulate magnetite is 5.
If it is less than 0% by weight, it is difficult to obtain the image density and the required signal intensity. Fixing strength exceeding 40% by weight is lowered, and signal strength is apt to be excessive. On the other hand, the amount of the acicular magnetite adhered to the toner surface is preferably 1.0 to 10% by weight, more preferably 2.0 to 8.0% by weight, based on 100 parts by weight of the toner. If the attached amount of the acicular magnetite is less than 1.0% by weight, it is difficult to obtain a required signal intensity, and if it exceeds 10% by weight, the signal intensity tends to be excessive. In addition, acicular magnetite that does not adhere to the toner surface appears, which impairs the life of the toner. Further, the ratio of acicular magnetite on the surface of the toner is preferably 0.10 to 0.50 with respect to 1.0 of granular magnetite added to the inside of the toner by weight.
If it is less than 0.10, the signal strength becomes insufficient, and if it exceeds 0.5, the signal strength exceeds the appropriate range.
A reading error easily occurs in the reader sorter of the reader of the R system. The residual magnetism of the granular magnetite used in the present invention is preferably 5 to 15 emu / g, and 8 to 10 emu / g.
13 emu / g is more preferred. 70-95 saturation magnetization
emu / g is preferable, and 75 to 85 emu / g is more preferable. If the residual magnetization exceeds 15 emu / g, the magnetization and the signal intensity tend to be excessive. On the other hand, if the residual magnetization is less than 5 emu / g, the signal intensity becomes insufficient, causing a reading error. If the saturation magnetization is less than 70 emu / g, the saturation magnetization required for development cannot be obtained, so that a sufficient image density cannot be obtained.
On the other hand, if it exceeds 95 emu / g, the saturation magnetization required for development will be exceeded, so that the problem of fog increase in the non-image area tends to occur. As the granular magnetite, the particle diameter is 0.2 to 0.1.
A general material having an aspect ratio of about 3 μm and an aspect ratio of 2.0 or less can be applied to the present invention. The residual magnetization of the acicular magnetite used in the present invention is preferably 20 to 50 emu / g,
25-40 emu / g is more preferred. The saturation magnetization is 70
-95 emu / g is preferable, and 75-85 emu / g is more preferable. When the residual magnetization is less than 20 emu / g, the signal intensity is insufficient, and when it exceeds 50 emu / g, the signal intensity tends to be excessive. When the saturation magnetization is less than 70 emu / g,
The saturation magnetization required for development cannot be obtained, and if it exceeds 95 emu / g, the saturation magnetization required for development tends to be exceeded. As the acicular magnetite, a general magnetite having a particle diameter of about 0.6 μm and an aspect ratio of 2.0 or more can be applied. Further, according to the present invention, when acicular magnetite is contained in the toner, the dispersibility is inferior, so that the problem of large variations in signal intensity between production lots can be solved by attaching the magnetite to the toner surface.

The MICR toner of the present invention may contain a charge control agent, a colorant, a release agent, and other additives as necessary. The MICR toner of the present invention preferably contains a charge control agent. The charge control agent includes one that imparts positive charge to the toner and one that imparts negative charge to the toner. Examples of the charge control agent for imparting positive charge include, for example, denatured products such as nigrosine and fatty acid metal salts, and quaternary ammonium such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate. Salts, diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide, and diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate can be used alone or in combination of two or more. Of these, particularly preferred are nigrosine compounds and quaternary ammonium salts. Examples of the charge control agent imparting the negative charge property include an acetylacetone metal complex, a monoazo metal complex, an organic metal compound such as a naphthoic acid or salicylic acid-based metal complex or a salt, a chelate compound, calex arene, a boron-containing organic substance, or the like. Two or more types can be used in combination. Among these, salicylic acid-based metal complexes,
Monoazo metal complexes are preferably used. A preferable addition amount of the charge control agent is 0.1 to 10% by weight, preferably 1.0 to 5.0% by weight based on the toner.

It is preferable that the toner of the present invention contains a release agent in order to ensure the releasability of the fixing heat roll and the rubbing resistance of the magnetic head. Release agents include waxes, higher fatty acids, higher fatty acid amides, hardened castor oil and the like. As waxes, low molecular weight polyethylene,
Examples include polyolefin waxes such as low molecular weight polypropylene, paraffin wax, Fischer-Tropsch wax, carnauba wax, candelilla wax and rice wax. These release agents can be used alone or as a mixture. As the release agent of the present invention, a polyolefin wax having excellent offset resistance is preferable. This is because even if the printed image is visually acceptable, a reading error may occur in the reader sorter of the reader of the MICR system due to the defective offset. The content of the release agent is 1.5 to the toner.
-15% by weight is preferred, and 2.0-10% by weight is more preferred.

Since the MICR toner of the present invention contains black magnetite particles, there is usually no problem if a colorant is not used, but a colorant can be used if necessary. Colorants include carbon black, aniline blue, chalco oil blue, chrome yellow, ultramarine blue, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, rhodamine dye, anthraquinone dye, monoazo And disazo pigments, mixtures thereof and others. It is necessary that these colorants are contained in such a proportion that a visible image having a sufficient image density is formed, and the proportion is usually 20 parts by weight or less based on 100 parts by weight of the binder resin.

The toner of the present invention may contain a higher fatty acid, an olefin-maleic anhydride copolymer or the like in order to protect the photoreceptor and obtain a high-quality image without deteriorating the developing characteristics. It may be added.

In producing the first MICR toner of the present invention, to attach the acicular magnetite to the toner surface, the toner and the acicular magnetite are mixed with a mixer such as a Henschel mixer, and the mixture is applied to the surface of the toner. The toner may be adhered by gliding, or at least a part of the needle toner may be buried. The burial may be performed by a strong impact force treatment such as hybridization or a heat treatment in a hot air flow.

The surface of the second MICR toner according to the present invention needs to have silica or titanium oxide as a fluidizing agent attached thereto in addition to acicular magnetite. The presence of these fluidizing agents can optimize the image density. The fluidizing agent is preferably hydrophobic silica. The addition of the acicular magnetite and the fluidizing agent may be performed at the same time, but preferably comprises, for example, the following steps. A first step of producing a toner containing a binder resin and particulate magnetite, a second step of attaching acicular magnetite to the surface of the toner
In this step, it is preferable that a part of the acicular magnetite is buried. A third step of further attaching a fluidizing agent to the toner surface. According to the above process, a part of the acicular magnetite is buried to make it difficult to fall off, and then a fluidizing agent is attached. Therefore, since the fluidizing agent is present outside the toner, its action is not hindered by the acicular magnetite. Since the acicular magnetite does not exist at the outermost part of the toner, it does not easily fall off by sliding of the magnetic head. In addition, the present invention
The invention can be applied not only to the melt-kneading / pulverizing method but also to a toner produced by a polymerization method. The MICR toner of the present invention can also be used for general printing.

[0016]

The present invention will be described below based on examples and comparative examples. In addition, all the compounding parts number means a weight part. <Example 1>-66.0 parts of styrene-acrylic acid ester copolymer resin (trade name: CPR-100, manufactured by Mitsui Chemicals, Inc.)-1.5 parts of chromium azo dye, negative charge control agent (Hodogaya Chemical Industry Co., Ltd.) 30.0 parts of granular magnetite (trade name: BL-100, residual magnetization 8.5 emu / g, saturation magnetization 85 emu / g)-2.5 parts of polypropylene wax (Sanyo Chemical Industries, Ltd.) Company name: Viscol 550P) The above materials are dry-mixed with a super mixer, hot-melted and kneaded with a twin-screw extruder to obtain a kneaded product, pulverized by a jet mill, and classified by a dry air classifier to obtain a volume. Average particle size is 8μ
m was obtained. To 100 parts of the toner, acicular magnetite (trade name: MAT-230, manufactured by Toda Kogyo KK)
Remanent magnetization 30 emu / g, saturation magnetization 81.8 emu /
g) After adding 6.0 parts and stirring in a Henschel mixer for 5 minutes to bury at least a portion of the acicular magnetite on the toner surface, hydrophobic silica (trade name: R972, manufactured by Nippon Aerosil Co., Ltd.) 5 parts were added, and the mixture was again stirred in a Henschel mixer for 5 minutes to adhere to the surface of the toner to prepare a MICR toner of the present invention. <Example 2> 66.0 parts of polyester resin (trade name: FC-1198, manufactured by Mitsubishi Rayon Co., Ltd.) 1.5 parts of chromium azo dye, negative charge control agent (trade name: Bontron S-, manufactured by Orient Chemical Industries, Ltd.) 44)-30.0 parts of granular magnetite (trade name: EPT-500, manufactured by Titanium Industry Co., Ltd., residual magnetization: 11.6 emu / g, saturation magnetization: 83.0 emu / g)-2.5 parts of polyethylene wax (manufactured by Hoechst) Name: PE-130) The above raw materials were dry-mixed with a super mixer, hot-melted and kneaded with a twin-screw extruder to obtain a kneaded product, pulverized with a jet mill, and then classified with a dry airflow classifier to obtain volume average particles. 8μ diameter
m was obtained. Needle magnetite (Kanto Denka Kogyo Co., Ltd., trade name: C
J3000B, residual magnetization of 34.3 emu / g, saturation magnetization of 83.2 emu / g), and stirred in a Henschel mixer for 5 minutes to bury at least a portion of the acicular magnetite on the surface of the toner. Thereafter, 1.5 parts of hydrophobic silica (trade name: R972, manufactured by Nippon Aerosil Co., Ltd.) was added, and the mixture was again stirred in a Henschel mixer for 5 minutes, and adhered to the toner surface to prepare a MICR toner of the present invention.

Comparative Example 1 A comparative toner was prepared in the same manner as in Example 1 except that the granular magnetite BL-100 of Example 1 was not used. <Comparative Example 2> Acicular magnetite MAT-23 of Example 1
A comparative toner was prepared in the same manner as in Example 1 except that 0 was not used. Comparative Example 3 Granular magnetite BL-100 of Example 1
Comparative Example 1 was prepared in the same manner as in Example 1 except that was changed to acicular magnetite MAT-230. <Comparative Example 4> Acicular magnetite MAT-23 of Example 1
Comparative toner was prepared in the same manner as in Example 1 except that 0 was changed to granular magnetite BL-100. <Comparative Example 5> Acicular magnetite MAT-23 of Example 1
Comparative toner was produced in the same manner as in Example 1 except that 0 was added to the inside of the toner without adhering to the toner surface.
Example 1 and Comparative Example 5 were manufactured in 10 lots each, and the dispersion of the initial signal intensity was compared.

<Evaluation Test> Using a commercially available magnetic one-component printer (printing speed A4: 16 sheets / min.), Printing was performed using the toners of Examples and Comparative Examples, and image density, fog, rub fixing strength, and tape peeling were evaluated. The strength and signal strength were evaluated. * The evaluation method is as follows. 1) Image density: Macbeth reflection densitometer (RD91
In 4), the initial density of the solid image of 25 mm × 25 mm and the density after 20,000 sheets were measured. 2) Fog: The whiteness of the non-image area was measured with a color difference meter ZE2000 manufactured by Nippon Denshoku Co., Ltd., and the value of (whiteness before printing minus whiteness after printing) was defined as the fog value. 3) Rubbing fixing strength (residual rate%): 25 mm × 25 mm
3 of a solid image with sand eraser under pressure of 500 g / cm ²
Reciprocating rubbing was calculated from the image density X before rubbing and the image density Y after rubbing according to the following equation. The characteristics were substituted for the strength of the magnetic head against sliding. Rubbing fixing strength (%) = Y / X × 100 4) Tape peeling strength (residual rate%): A cellophane tape is stuck on a 25 mm × 25 mm solid image and peeled off. It was calculated by the following equation. It was used as a substitute for the fixing strength when touching other things or applying a tape. Tape peeling strength (%) = Q / P × 100 5) Signal strength (%): M is used for MICR character reader
The signal intensity at the initial stage and after 20,000 sheets were measured using MINIMCR RS232 from Agtek. If the signal strength is 70 to 200%, no reading error occurs in the reader sorter of the reader of the MICR system.

Table 1 shows the evaluation results.

[Table 1] As is clear from Table 1, the MICR toners of Examples 1 and 2 according to the present invention exhibited image density, fog, rub-fixing strength, tape peeling strength, and signal strength over 20,000 sheets from the initial stage of continuous printing. In terms of characteristics, MI
It was confirmed that it was practically satisfactory for CR. In Comparative Example 1, since no granular magnetite was contained in the toner, the saturation magnetization required for development was insufficient, no image density was obtained, and there were many fogs. Further, since no image density was obtained, the signal intensity was 70% or less of the lower limit of the appropriate range. In Comparative Example 2, since no acicular magnetite was present on the toner surface, the residual magnetization was insufficient, and the signal intensity was 70%, which is the lower limit of the appropriate range.
% Or less. In Comparative Example 3, since the acicular magnetite was also contained in the toner, the fixing strength was lowered, and the signal strength was significantly higher than the upper limit of 200% of the appropriate range over 20,000 sheets from the beginning of printing. In Comparative Example 4, since the acicular magnetite was not attached to the toner surface, the signal intensity was 70% of the lower limit of the appropriate range between 20,000 sheets after the initial printing.
It became the following. In Comparative Example 5, since the acicular magnetite was contained in the toner, the initial signal intensity varied greatly between production lots.

[0020]

According to the present invention, the magnetic head has abrasion resistance, and by maintaining an appropriate signal strength, no reading error occurs, and there is no problem in image quality such as image density and fog. Further, it is possible to provide a MICR toner having a small variation in signal intensity between manufacturing lots.

Claims (6)

[Claims] 1. A toner for MICR, wherein at least acicular magnetite is attached to the surface of a toner containing a binder resin and particulate magnetite. 2. A toner for MICR, wherein acicular magnetite and a fluidizing agent are attached to the surface of a toner containing a binder resin and particulate magnetite. 3. The MICR toner according to claim 2, wherein the fluidizing agent is hydrophobic silica. 4. The method according to claim 1, wherein the granular gnetite has a particle size of 5.0 to the toner.
2. The composition according to claim 1, wherein the amount is from 40 to 40% by weight.
Or the MICR toner according to item 2. 5. The method according to claim 1, wherein the acicular magnetite is used in the toner.
2. The composition according to claim 1, wherein 0 to 10% by weight is adhered.
Or the MICR toner according to item 2. 6. The remanent magnetization of the granular magnetite is 5 to 15.
3. The MICR according to claim 1, wherein the emu / g, the saturation magnetization is 70 to 95 emu / g, the residual magnetization of the acicular magnetite is 20 to 50 emu / g, and the saturation magnetization is 70 to 95 emu / g. For toner.