JPH07271085A - Toner for magnetic ink character recognition printing - Google Patents

Abstract

PURPOSE:To obtain a toner excellent in preservability and forming a clear toner image by fixation by blending a toner for magnetic ink character recognition printing contg. polystyrene resin or polyester resin as the principal component of a binder with Fischer-Tropsch wax having a specified mol.wt. and specified thermal characteristics. CONSTITUTION:This toner contains polystyrene resin or polyester resin as the principal component of a binder, particles of a magnetic material and Fischer-Tropsch wax having a wt. average mol.wt. of >=1,000 and endothermic bottom peak values measured by DSC in the range of 100-120 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used for printing magnetic ink character recognition.

[0002]

2. Description of the Related Art In checks, certificates, invoices issued automatically by credit companies, and highway pass tickets, a combination of numbers and symbols called fonts is printed with magnetic ink and read magnetically. In recent years, it has become popular to manage or sort by using MICR (MCR (M
organic Ink Character Rec
It is called an ignition system. For example,
JP-A-2-134648 and JP-A-5-80582
No. 5,034,298 and the like.

In this MICR system, it is necessary to print magnetic ink character recognition (hereinafter referred to as MICR), which is a combination of fonts, on checks, certificates, etc. Therefore, in the case of an electrophotographic printer, printing is performed. As the ink, magnetic powder ink generally called toner is used. The MICR toner has magnetic material particles dispersed in a binder resin and is required to have the following characteristics.

(1) No caking occurs during storage or in the printing apparatus (storability). (2) A clear MICR check can be printed. (3) At the time of reading, development (hereinafter referred to as offset) and image smearing (image bleeding) that cause a part of the printed toner to move and adhere to the reading magnetic head to stain the head do not occur. If offset or image smearing occurs, the MICR reader will be
The CR check cannot be read correctly and as a result such certificates are rejected.

Therefore, conventionally, there has been studied a technique for reducing the rejection rate by preventing offset and image smearing in a MICR reader. For example, Japanese Patent Laid-Open No.
-134648 and JP-A-5-80582 report that an aliphatic hydrocarbon or a higher alcohol is blended together with magnetic material particles in a binder resin.

In addition, in US Pat. No. 5,034,298, it is disclosed in USP
No. 5,080,986 discloses that a capsule toner is further used. However, these toners for MICR do not always realize a satisfactory rejection rate. Also, if a high molecular fluorine compound is blended in the toner, the fixing rate on paper during printing will decrease,
This leads to a reduction in reading rate due to image defects.

Regarding the addition of the Fischer-Tropsch wax to the general electrophotographic toner, JP-A-61-273554 and JP-A-4-15 are available.
It is reported in Japanese Patent No. 3659. However, the waxes used therein are different from the Fischer-Tropsch wax of the present invention, and do not suggest the use as MICR toe.

[0008]

DISCLOSURE OF THE INVENTION The present invention has excellent storability, can clearly print MICR, and can prevent offset to the read head and image smearing.
MICR capable of reducing the rejection rate of readers
Toner for toner is provided.

[0009]

A magnetic ink character recognition (MICR) printing toner of the present invention comprises a polystyrene resin or a polyester resin as a main binder component, a magnetic material particle, and a weight average molecular weight of 1,000 or more, In addition, the endothermic bottom peak value measured by DSC is characterized by containing Fischer-Tropsch wax in the range of 100 to 120 ° C.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The toner of the present invention contains polystyrene resin or polyester resin as a main binder component. The polystyrene resin may be a homopolymer of styrene or a copolymer with another monomer copolymerizable with styrene. Copolymerizable monomers include p-chlorostyrene; vinylnaphthalene; ethylene unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene; vinyl halides such as vinyl chloride, vinyl bromide, vinyl fluoride; vinyl acetate. , Vinyl propionate, vinyl benzoate, vinyl butyrate and the like; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroacrylate. -(Meth) acrylic acid esters such as ethyl, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate; other acrylic acids such as acrylonitrile, methacrylonitrile, acrylamide Conductor; vinyl methyl ether, vinyl ethers such as vinyl isobutyl ether; vinyl methyl ketone, vinyl ethyl ketone,
Vinyl ketones such as methyl isopropenyl ketone; N
There are N-vinyl compounds such as -vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidene, and one or more of these can be copolymerized with a styrene monomer.

The styrene resin has a weight average molecular weight of 80.
000 to 200,000 is preferable, and a weight average molecular weight M
It is preferable that the ratio Mw / Mn of w and the number average molecular weight Mn is 10 or more. The polyester resin is obtained by polycondensation or copolycondensation of an alcohol component and a carboxylic acid component, and specific examples of each component used include the following.

Examples of the divalent or trivalent or more alcohol component include the following. 1) diols; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4
-Butanediol, neopentyl glycol, 1,4-
Butenediol, 1,5-pentanediol, 1,6-
Hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc.

2) Bisphenols; bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropyleneized bisphenol A, and other etherified bisphenols.

3) Trihydric or higher alcohols; sorbitol, 1,2,3,6-hexanetetrol, 1,4-
Sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,2. 4-butanetriol, trimethylolethane, trimethylolpropane, 1,
3,5-trihydroxymethylbenzene and the like. As the divalent or trivalent or higher carboxylic acids, divalent or trivalent carboxylic acids, their acid anhydrides or their lower alkyl esters are used, and the carboxylic acids are exemplified below.

4) divalent carboxylic acid; maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, Malonic acid, or n-butylsuccinic acid,
n-butenyl succinic acid, isobutyl succinic acid, isobutenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, etc. Alkyl or alkenyl succinic acid etc.

5) Trivalent or higher carboxylic acids; 1,2,4
-Benzenetricarboxylic acid (trimellitic acid), 1,
2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,
5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,
2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, enpol trimer acid and the like. Acid anhydrides or lower alkyl esters of these carboxylic acids can also be used.

Further, for example, JP-B-46-12680, JP-A-48-81540 and JP-A-50-750.
43, Japanese Patent Publication No. 52-22996, and Japanese Patent Laid-Open No. 5
JP-A-4-86342 discloses that a polyester resin is used as a binder resin for toner,
These polyester resins can also be used as a binder resin for the MIRC toner of the present invention. The softening point of the polyester resin is preferably 110 to 150 ° C, more preferably 120 to 140 ° C. further,
Other binder resins may be used in combination with the polystyrene resin and / or the polyester resin.
As these other binder resins, epoxy resin, polyamide, polymethylmethacrylate, polyvinyl butyral and the like are used.

The binder resin is preferably contained in the MICR toner in an amount of 60 to 85% by weight, more preferably 60 to 80% by weight. As the magnetic material particles, magnetite, iron powder, ferrite and the like are used, and it is preferable that the amount of magnetic memory when the magnetic field is zero after applying 10 kilo Oersted, that is, the residual magnetization is about 15 to 35 emn / g. is there. Magnetic material particles have an average particle size of 0.2
The amount is preferably about 0.5 to 0.5 μm, and in the two-component developing method, it is preferably 15 to 40% by weight, and more preferably 20 to 30% by weight in the MICR toner.

Fischer-Tropsch wax is obtained from coal as a raw material by catalytic hydrogenation of carbon monoxide,
It is a linear hydrocarbon wax having a small number of iso-structured molecules and side chains, and is also called "sazar wax" because it is available from Sazol Co. of South Africa. Although there are various types and grades of Fischer-Tropsch wax, as a result of diligent studies by the present inventors, a wax having a relatively high molecular weight and a high melting point has excellent storage stability and is good as an additive to a toner for MIRC. It has been found that it has various characteristics.

That is, the weight average molecular weight (Mw) of a typical Fischer-Tropsch wax is about 800. For example, H1 and H2 represented by the general formula CnHm (m = 2n + 2, n is an integer) have a grade of C ₄₈ H ₉₈ and Mw.
= 814, C1 grade has C ₅₇ H ₁₁₆ and Mw = 794, but the action and effect of the present invention cannot be obtained with such a low molecular weight Fischer-Tropsch wax.
To obtain the effects of the present invention, the weight average molecular weight Mw
Must be 1000 or more, and preferably M
w is 1100 to 1600. When the Mw is less than 1000, not only the storage stability of the toner at use environment temperature (5 to 50 ° C.) is not sufficiently improved, but also the hardness is insufficient.

Specific examples of the Fischer-Tropsch wax that can be used in the present invention include C105 (Mw = about 1300) of the Sazar wax (C2 (C ₉₀ H ₁₈₂ ) (Mw = 1262), which is purified by the fractional distillation method. ), SPRAY105 (Mw = about 1300), which is a fine particle product.

In addition, DSC (differential)
The endothermic bottom peak value is 100 to 1 as measured by a scanning calorimeter (scanning calorimeter).
It is necessary to use Fischer-Tropsch wax present in the range of 20 ° C, preferably in the range of 100-115 ° C. Here, the endothermic bottom peak value means DSC
The bottom value of the remarkable endothermic peak that first appears when the temperature is raised by, and it is point A in FIGS.
As such Fischer-Tropsch wax,
As in the case of the above molecular weight, the following can be exemplified.

Sazar wax C1 (high molecular weight grade product by crystallization of H1): endothermic bottom peak value 10
6.5 ° C Sazar Wax C105 (C1 purified product by fractionation method): Endothermic bottom peak value 102.1 ° C Sazar Wax SPRAY105 (C105 fine particle product): Endothermic bottom peak value 102.1 ° C

By using the wax of the present invention as described above, sharp heat response, a large decrease in viscosity upon softening, smoothness of a toner image formed, proper hardness can be obtained, and storage stability of the toner can be obtained. Sex is improved.

On the other hand, Fischer-Tropsch wax having an endothermic bottom peak value at 100 ° C. or lower has disadvantages such as deterioration in storage stability of toner due to the presence of low-molecular weight wax, isoparaffin, and side chains, and is used. It causes troubles such as toner caking in the environment. In addition, offset and image smearing deteriorate, and the rejection rate increases. For example, Sazar wax H1 is 83.5 ° C
Although a DSC endothermic bottom peak is seen in Fig. 3, the peak at 83.5 ° C is due to the presence of wax side chains and isoparaffin. The reason why the Fischer-Tropsch wax of the present invention is added to the toner for MICR and exhibits excellent effects is considered as follows.

When the toner is fixed during printing, the Fischer-Tropsch wax responds sharply to heat and melts, and the viscosity becomes extremely small during melting, so that the wax quickly migrates to the surface of the toner image, and the toner image has a smooth surface. Give sex. The Fischer-Tropsch wax of the present invention has a small linear structure of the molecule, that is, an iso structure molecule and a side chain, so that the friction property (friction resistance) is small and the hardness is appropriate. Therefore, even if the read head comes into contact with the read head, offset and image smearing do not occur, and the rejection rate is reduced.

Fischer-Tropsch wax
It has good compatibility with both polystyrene-based and polyester-based binder resins. Moreover, since it has an appropriate softening property, it does not cause caking during storage or in the printer (usually at a maximum of about 55 ° C) and has excellent storability, and during toner image formation by the printer (developing / fixing process). In this case, a sharp image is formed in combination with the sharp thermal response described above.

The Fischer-Tropsch wax of the present invention is preferably contained in the MICR toner of the present invention in an amount of 1 to 5% by weight, more preferably 1 to 4% by weight.
If the content is less than 1% by weight, the effects of the present invention may not be sufficiently exhibited, while if it exceeds 5% by weight, drum filming may occur or the carrier may be contaminated.

Waxes other than the Fischer-Tropsch wax of the present invention can be used in combination in the toner of the present invention. For example, low molecular weight polyolefin wax such as polyethylene wax and polypropylene wax,
Teflon-based wax can be used.

The toner for MICR of the present invention further comprises a conventional component as a toner, for example, a charge control agent such as nigrosine and a metal-containing dye, carbon black, and various colorants for color toner (for example, JP-A-61-273554). reference)
And the like, surface modifiers such as hydrophobic silica, and the like can be added. The toner for MICR of the present invention may be mixed with a developer carrier such as a ferrite carrier to be a two-component developer, or may be used alone as a one-component developer to be used by an appropriate method.

The average particle size of the MICR toner of the present invention is
About 5 to 12 μm is suitable. The MICR toner of the present invention is printed by a conventional electrophotographic method to form MICR. That is, the toner image formed on the photoconductor by the toner of the present invention is preferably transferred and fixed on a transfer material such as paper by a heat roll fixing device. In this case, the fixing temperature is preferably 120 to 190 ° C., preferably 13
It is 0 to 180 ° C. MICR formed on paper
Magnetized once, and its magnetic retention magnetization (magnetic memory)
By reading in, the printed magnetic pattern can be recognized.

[0032]

According to the present invention, MI containing polystyrene resin or polyester resin as the main binder component.
By blending a CR toner with a Fischer-Tropsch wax having specific molecular weight and thermal characteristics, the toner has excellent storage stability, prevents the occurrence of caking during storage and use outside the device, and provides a clear toner by fixing. Image (MICR) is formed, and at the time of this reading,
Offsets to the read head and image bleeding are prevented, and the rejection rate of the MICR reader is reduced.

[0033]

【Example】

[Measurement of Thermal Properties by DSC] As the DSC, SSC-5000 manufactured by Seiko Instruments Inc. was used. For measurement, put about 10 mg of wax sample in the sample holder,
This was carried out using 10 mg of alumina as a reference material. 25 ℃ after heating up to 160 ℃ at 5 ℃ / min
FIGS. 1 to 4 show the endothermic characteristics when the temperature was cooled to 160 ° C. and the temperature was raised to 160 ° C. again.

FIG. 1: Sazaar wax SPRAY105
(Endothermic bottom peak value: 102.1 ° C) Fig. 2: Sazaar wax C2 (Endothermic bottom peak value: 1
(06.5 ° C) Fig. 3: Sazaar wax H1 (endothermic bottom peak value: 8)
3.5 ° C.) FIG. 4: Sazaar wax A1 (Endothermic bottom peak value: 7)
Example (Preparation and evaluation of toner for MICR) Binder resin 70 parts by weight Needle-like magnetite 25 parts by weight (residual magnetization: 30 emu / g, 10 KOe) Wax 3 parts by weight Nigrosine dye 2 parts by weight

The above components were melt-kneaded with the properties and compositions shown in Table 1, pulverized and classified to obtain a powder having an average particle size of 7 μm. To this powder, 0.5% of silica (SiO ₂ ) was externally added, mixed, and adhered to the surface to prepare MICR toners of Examples and Comparative Examples of the present invention. 5% by weight of this toner
And a non-coated ferrite carrier 95% by weight are mixed to form a developer, and a printer manufactured by Kyocera (Ecosys FS-1
500) was used to print a MICR pattern to create a check, and a good image was obtained.

Rejection rates were measured by passing 5000 consecutive checks with MICR patterns printed through a MICR reader. Further, after passing 5000 sheets, the offset and stain of the reading head portion were visually confirmed and evaluated according to the following criteria. ◯: There is no stain on the head. Δ: There is stain on a part of the head. X: There is severe stain. Further, the toner for MICR is packed in a container and heated at 50 ° C. for 10 minutes.
From 5 points (good) to the occurrence state of caking after storage for 0 hours
The evaluation was made on a scale of 1 (faulty). The above results are shown in Tables 1 and 2.

[0037]

[Table 1]Table 1: Contents of binder resin and wax used UseWorking Wax Binder resin type Mw Endothermic bottom peak value Example 1 Styrene / acrylic resin SPRAY105 1300 102 ° C Example 2 Polyester resin C2 1262 106 ° C Comparative Example 1 Styrene / acrylic resin H1 800 83 ° C Comparative Example 2 Styrene / acrylic resin PP − − Polyester resin: Bisphenol A, terephthalic acid,
Co-condensation of alkenylsuccinic acid and trimellitic anhydride
Bisphenol polyester resin Styrene / acrylic resin: Styrene / n-butyl acryl
Rate copolymer (copolymerization ratio = 70/30) Wax used: SPRAY105, C2, H1
Sazar wax from Sazar. PP is polypropylene
Wax (Viscor 550P, Sanyo Kasei Co., Ltd.)
Made)

[0037]

[Table 2] Table 2: Evaluation results 5000 sheets Rejection rate Offset / dirt storability Example 1 0.1 ○ 4 Example 2 0.1 ○ 4 Comparative example 1 0.2 △ 2 Comparative example 2 0.7 × 3

[Brief description of drawings]

FIG. 1 D of the Fischer-Tropsch wax of the present invention
It is a graph which shows a SC curve.

FIG. 2 D of the Fischer-Tropsch wax of the present invention
It is a graph which shows a SC curve.

[Fig. 3] D of Fischer-Tropsch wax of Comparative Example
It is a graph which shows a SC curve.

FIG. 4 D of the Fischer-Tropsch wax of the comparative example
It is a graph which shows a SC curve.

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Claims (1)

[Claims] 1. A polystyrene-based resin or a polyester-based resin as a main binder component, magnetic material particles and a weight average molecular weight of 1000 or more, and an endothermic bottom peak value measured by DSC in the range of 100 to 120 ° C. Toner for magnetic ink character recognition printing, characterized by containing Fischer-Tropsch wax.