JPH0643689A - Magnetic developer and magnetic ink symbol recognizing method - Google Patents

Abstract

PURPOSE:To provide a magnetic developer excellent in thin line reproducibility and resolution and exerting an excellent recognition rate especially when used in a magnetic ink symbol discriminating system and to furnish a magnetic symbol recognition method. CONSTITUTION:This magnetic developer has a magnetic toner contg. at least a binder resin, a magnetic substance and a hydrocarbonic wax. The onset temp. of the toner in an endothermic peak when heated is at <=105 deg.C in the DSC curve measured by a differential scanning colorimeter, and the endothermic peak is at 100-120 deg.C. The exothermic peak when cooled is at 62-75 deg.C, and the exothermic peak strength ratio is at >=5X10<-3>. The residual magnetization of the magnetic substance is controlled to 12-30emu/g in the magnetic field of 10,000 oersted and the coercive force to 130-300 oersted. A magnetic ink symbol is recognized by using this magnetic developer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic device applied to a developing device for forming a latent image on an image bearing member such as an electrophotographic photosensitive member or an electrostatic recording dielectric member and visualizing the latent image. The present invention relates to a developer and a magnetic ink symbol recognition method for reading and identifying the magnetism of a magnetic ink symbol printed using the magnetic developer.

The present invention further provides magnetic ink symbol identification (Ma).
genetic Ink Character Reco
The present invention relates to a magnetic developer suitable for printing characters having magnetism used in a gnition system.

In the electrophotographic image forming method, the magnetic developer of the present invention is a digital latent image in which a latent image is represented by unit pixels, and the unit pixels are represented by on / off binary or finite gradation. Can be preferably used as a magnetic developer for developing an image by reversal development.

[0004]

2. Description of the Related Art Conventionally, for example, a developing device for visualizing a latent image formed on a surface of a photosensitive drum as an electrostatic latent image bearing member with a magnetic toner as a one-component developer has been known. Due to the friction and the friction between the sleeve as a developing carrier and the magnetic toner particles, an electric charge having a polarity opposite to the electrostatic image charge formed on the photosensitive drum and the development reference potential is applied to the magnetic toner particles, and the magnetic toner is transferred to the sleeve. It is applied very thinly on top and conveyed to the development area formed by the photosensitive drum and sleeve, and in the development area the magnetic toner is ejected by the action of the magnetic field of the magnet fixed in the sleeve to cause electrostatic latent image on the photosensitive drum. It is known to visualize.

Further, in recent years, as image forming apparatuses such as electrophotographic copying machines have become widespread, their applications have been expanded in various ways. Under such a background, magnetic ink symbol identification (Magnetic In) has been applied as an application field of electrophotographic printers.
k Character Recognition Hereinafter, simply referred to as MICR. ) A character printing machine used in the system has been devised.

The MICR system mainly prints checks, bills, etc., such as issuing bank, amount, account number, etc., with magnetic ink, and efficiently sorts and sorts at a clearing house using a magnetic reader. It is a system devised for the purpose. Conventionally, offset printing using magnetic ink has been the mainstream, but with the increase in commercial transactions such as personal checks and bills, the demand for small MICR character printing machines (hereinafter simply referred to as MICR encoders) has increased. is doing.

The conventional small MICR encoder is
The mainstream was the impact printer that applied the thermal transfer method, but in this case most single-function machines that print only MICR characters cannot be used to create general documents, and improvements are required. .

There is a demand for an electrophotographic printer capable of printing general documents and / or graphics, capable of printing MICR characters, and exhibiting a good MICR recognition rate. When an electrophotographic printer is applied to a MICR encoder, if the magnetic developer known in the prior art is used as it is, the accuracy rate (recognition rate) of magnetic reading by the MICR reader / sorter is in the case of MICR characters using offset printing or impact printer. Compared to, it is extremely low and not practical.

Securities with MICR characters printed are M
On average, ICR leaders and sorters pass about 10 times. It is rubbed against the magnetic head at high speed every time the paper is passed for magnetic reading. Therefore, it is necessary that the magnetic developer for printing MICR characters does not fade or fall off due to rubbing.

MICR characters are, for example, ANS (Amer
ican National Standard) x
9.27-198x or JIS C6251-19
There is a standard called E-13B defined in 80. E
The -13B standard consists of numbers from 0 to 9 and four types of symbols, and by combining these, bank codes, branch codes, account numbers, amounts, etc. are printed on securities.

In order to improve the recognition rate by the MICR reader / sorter, it is required that the shape and dimensions of the printed MICR characters are reproduced with high accuracy, and the characters are fine and faithful without being crushed or broken. It is necessary to reproduce it.

In order to achieve a high recognition rate in printing MICR characters by an electrophotographic printer, magnetic development containing a specific magnetic substance having magnetic characteristics different from those of magnetic substances used in conventional magnetic developers. It is necessary to use agents.

That is, a magnetic material having a relatively large residual magnetization σr is required.

Like a magnetic developer of a general electrophotographic printer, it exhibits good triboelectric chargeability and is required to be uniformly applied on a developer carrier (hereinafter referred to as a sleeve) of a developing machine. . In order to satisfy this condition, the magnetic permeability of the magnetic material contained in the magnetic developer is also important.

Japanese Examined Patent Publication No. 59-7379 includes a cobalt-substituted triiron tetraoxide powder having a major axis / minor axis ratio of 1 to 5, a residual magnetization of 10 to 20 emu / g, and a coercive force of 150 to 4.
A magnetic toner of 50 oersted has been proposed, but it is difficult to uniformly apply the toner layer on the sleeve, the triboelectrification property is poor, the image density is low, and the sharpness is poor.

Japanese Unexamined Patent Publication (Kokai) No. 63-108354 discloses an insulating magnetic capsule toner containing spherical magnetic powder having a major axis / minor axis ratio of 1 to 1.5 and a magnetic permeability of 3.80 to 6.00. A magnetic toner containing a ferromagnetic fine powder having a maximum magnetic permeability of 3.95 to 5.50 has been proposed and proposed in JP-A-59-204846. In this case, the image density is high, which is preferable, but improvement is required to meet more severe requirements such as resolution and suitability for reversal development.

[0017]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic developer which solves the above problems and a magnetic ink symbol recognition method using the magnetic developer.

That is, an object of the present invention is to provide a magnetic developer which does not cause faint or missing MICR characters even when it is repeatedly passed through a MICR reader / sorter, and a magnetic ink symbol recognition method using the magnetic developer. To provide.

Further, an object of the present invention is to provide a magnetic developer which does not contaminate the magnetic head of the MICR reader / sorter even if it is repeatedly passed through the MICR reader / sorter, and magnetic ink symbol recognition using the magnetic developer. To provide a method.

Further, an object of the present invention is to obtain resolution, gradation and fine line reproducibility even in an image forming apparatus which forms a latent image by a digital image signal and develops the latent image by a reversal development method. A magnetic developer capable of forming an excellent toner image and a magnetic ink symbol recognition method using the magnetic developer.

Another object of the present invention is to provide a magnetic developer exhibiting an excellent recognition rate when used for MICR printing using an electrophotographic printer and a magnetic ink symbol recognition method using the magnetic developer. Is.

Another object of the present invention is to provide a magnetic developer which does not reduce the recognition rate even if it is repeatedly passed through an MICR reader / sorter, and a magnetic ink symbol recognition method using the magnetic developer. .

Further, an object of the present invention is to provide a magnetic developer which is excellent in fine line reproducibility and resolution and faithfully reproduces according to the standard even when MICR characters are printed, and a magnetic ink symbol recognition method using the magnetic developer. To do.

[0024]

The present invention achieves the above object by the following constitution.

That is, the present invention provides a magnetic developer having a magnetic toner containing at least a binder resin, a magnetic substance and a hydrocarbon wax, wherein the magnetic toner has a DSC curve measured by the following characteristic differential scanning calorimeter. In regard to the endothermic peak at the time of temperature increase, the onset temperature at the endothermic peak is 105 ° C. or lower, the endothermic peak temperature is in the range of 100 to 120 ° C., and the exothermic peak temperature at the time of cooling is 62 to It is in the range of 75 ° C., the exothermic peak intensity ratio is 5 × 10 ⁻³ or more, and the magnetic material has a remanent magnetization (σ _r ) in the range of 12 to 30 emu / g in a magnetic field of 10,000 oersteds. And a coercive force (Hc) in the range of 130 to 300 Oersted.

Furthermore, the present invention provides at least a binder resin,
In a magnetic developer having a magnetic toner containing a magnetic substance and a hydrocarbon wax, the magnetic toner has a DSC curve measured by the following characteristic differential scanning calorimeter:
Regarding the endothermic peak at the time of temperature rise and the exothermic peak at the time of temperature decrease, the onset temperature of the endothermic peak is in the range of 50 to 90 ° C., and there is at least one endothermic peak P1 in the region of the temperature of 90 to 120 ° C. P1 peak temperature ± 9
The maximum exothermic peak at the time of temperature decrease is satisfied within the range of ° C, and the magnetic substance has a remanent magnetization (σ _r ) in the range of 12 to 30 emu / g and a coercive force (in the magnetic field of 10,000 oersteds). Hc) is in the range of 130 to 300 oersteds.

Furthermore, the present invention prints a magnetic ink symbol on a recording material using a magnetic developer, imparts magnetism to the printed magnetic ink symbol, and reads and identifies the magnetism of the magnetized magnetic ink symbol. In the magnetic ink symbol recognition method described above, the magnetic developer has a magnetic toner containing at least a binder resin, a magnetic substance and a hydrocarbon wax, and the magnetic toner has a DSC measured by the following characteristic differential scanning calorimeter. In the curve, regarding the endothermic peak at the time of temperature rise, the onset temperature at the endothermic peak is 105 ° C. or lower,
The endothermic peak temperature is in the range of 100 to 120 ° C., and the exothermic peak temperature is 62 to 7 when the temperature is lowered.
The exothermic peak intensity ratio is 5 × 10 ⁻³ or more in the range of 5 ° C., and the magnetic material has a residual magnetization (σ _r ) of 12 to 30 in a magnetic field of 10,000 Oersted.
emu / g range and coercive force (Hc) of 130
To 300 Oersted range.

Furthermore, the present invention prints a magnetic ink symbol on a recording material using a magnetic developer, imparts magnetism to the printed magnetic ink symbol, and reads the magnetism of the magnetized magnetic ink symbol to identify it. In the magnetic ink symbol recognition method described above, the magnetic developer has a magnetic toner containing at least a binder resin, a magnetic substance and a hydrocarbon wax, and the magnetic toner has a DSC measured by the following characteristic differential scanning calorimeter. In the curve, the onset temperature of the endothermic peak is 50 with respect to the endothermic peak during temperature increase and the exothermic peak during temperature decrease.
To 90 ° C, and at least one endothermic peak P1 in the temperature range of 90 to 120 ° C, the endothermic peak P
1 has a maximum exothermic peak at the time of lowering the temperature within the range of ± 9 ° C., and the magnetic material has a residual magnetization (σ _r ) of 12 to 3 in a magnetic field of 10,000 Oersted.
0 emu / g and coercive force (Hc) of 13
The present invention relates to a magnetic ink symbol recognition method, which is in the range of 0 to 300 Oersted.

The magnetic developer of the present invention will be described in detail below.

The present invention relates to a magnetic developer having a magnetic toner containing at least a binder resin, a magnetic substance and a hydrocarbon wax, and the magnetic toner is measured by the following characteristic differential scanning calorimeter. In the DSC curve, regarding the endothermic peak at the time of temperature increase, the onset temperature at the endothermic peak is 105 ° C. or less, the endothermic peak temperature is in the range of 100 to 120 ° C., and the exothermic peak temperature at the time of lowering the exothermic peak temperature is One of the characteristics is that it is in the range of 62 to 75 ° C. and the exothermic peak intensity ratio is 5 × 10 ⁻³ or more, and it is a combination with a magnetic material having specific magnetic characteristics described later. According to this, the above-mentioned object can be achieved.

The behavior between heat and toner can be found by analyzing the data of the toner measured by a differential scanning calorimeter. That is, it is possible to know the heat exchange with the toner and the change in the toner state from the data. For example, it is possible to know whether the offset phenomenon can be prevented, the effect of heat during storage or actual use, such as blocking resistance, and how much the temperature rise affects the developability. it can.

At the time of temperature rise, the state change when heat is applied to the toner can be seen, and the wax component is transferred, melted,
An endothermic peak associated with dissolution is observed. The present invention is characterized in that the onset temperature of the endothermic peak at the time of temperature rise is 105 ° C. or lower, preferably 90 to 102 ° C., whereby the low temperature fixability is excellent. When the onset temperature of this endothermic peak exceeds 105 ° C., the temperature of plastic change in the short-time range becomes high, and low temperature offset resistance and fixability become poor.

Further, the present invention is characterized in that the endothermic peak temperature at the time of temperature rise is in the range of 100 to 120 ° C., preferably 102 to 115 ° C., and the wax in the toner melts in this temperature range. , Release effect is exerted, MIC
MICR even if the paper is repeatedly passed through the R leader / sorter
Characters are not blurred, and the magnetic head of MICR reader / sorter is not easily contaminated.

When the endothermic peak temperature is less than 100 ° C., it is shown that the plastic effect due to the melting of the wax is exhibited from a low temperature and the mechanical strength of the binder resin is remarkably lowered. In this case, although the release effect is exhibited when the paper is passed through the MICR reader / sorter, the MICR character may be faint when rubbing against the magnetic head of the MICR reader / sorter due to the decrease in mechanical strength of the binder resin. Are likely to occur, and at the same time easily contaminate the magnetic head, which is not preferable.

The endothermic peak temperature may be present in a region exceeding 120 ° C., but if no peak is present in a region in which the endothermic peak temperature is 120 ° C. or less at the same time, the melting temperature of the wax is too high, and in MICR printing, Since the releasability from the paper is also increased, MICR characters are apt to be lost due to the rubbing against the magnetic head when the paper is passed through the MICR reader / sorter, which is unfavorable as a cause of misreading.

When the temperature is lowered, changes in the state of the toner at room temperature and in the state of being cooled can be seen, and exothermic peaks due to the transition, solidification and crystallization of the wax component are observed. The present invention is characterized in that the exothermic peak temperature during cooling is in the range of 62 to 75 ° C, preferably 65 to 72 ° C, whereby good MICR characteristics are exhibited. If the exothermic peak temperature exceeds 75 ° C., the melting temperature of the wax is too high, and when the paper is passed through the MICR reader / sorter, MICR characters are likely to be lost due to rubbing against the magnetic head. When the temperature is lower than ℃, the plasticizing effect on the binder resin is maintained until a low temperature, MICR characters are liable to be scratched when rubbing against the magnetic head of the MICR reader / sorter, and at the same time, the magnetic head is easily polluted, which is not preferable. .

The present invention has an exothermic peak intensity ratio of 5 when the temperature is lowered.
× 10 ^-3 or more, preferably 10 × 10 ^-3 or more, more preferably wherein a is 15 × 10 ^-3 or more. The higher the exothermic peak intensity ratio during cooling, the higher the wax component density, the higher the degree of crystallinity, and the higher the hardness, resulting in an appropriate release effect. Even when the paper is passed through a MICR reader / sorter, MICR characters Is less likely to cause blurring, and also MI
It is hard to contaminate the magnetic head of CR reader / sorter.
If the exothermic peak intensity ratio is less than 5 × 10 ⁻³ , M
M when rubbing against the magnetic head of the ICR reader / sorter
It is not preferable because the ICR character is liable to be blurred and at the same time the magnetic head is easily contaminated. However, if the conditions are satisfied, peaks may exist in other regions at 75 ° C. or higher.

In the DSC measurement of the present invention, since the heat exchange of the toner is measured and its behavior is observed, it is necessary to measure with a highly accurate internal heat input compensation type differential scanning calorimeter from the measurement principle. As such a measuring instrument, for example, DSC-7 manufactured by Perkin Elmer Co. can be used.

The measuring method is ASTM D3418-82.
Carry out according to. As the DSC curve used in the present invention, the DSC curve measured when the temperature is raised once and the previous history is taken, and then the temperature is lowered and the temperature is raised at a temperature rate of 10 ° C./min is used.
The definition of each temperature is defined as follows.

Endothermic peak (positive direction is endothermic).

Peak rising temperature (LP): The temperature at which the peak curve is clearly deviated from the baseline. That is, it means the temperature at which the differential value of the peak curve is positive and the increase of the differential value starts to increase, or the temperature at which the differential value changes from negative to positive. (Specific examples are shown in FIGS. 1 and 3 to 6).

Peak onset temperature (OP): the temperature at the intersection of the tangent line and the baseline at the point where the differential value of the peak curve becomes maximum (a concrete example is shown in FIG. 1).

Peak temperature (PP): Peak top temperature (maximum peak in the region of 120 ° C. or lower).

Exothermic peak (negative direction is exothermic).

Exothermic peak temperature: Peak top temperature.

Exothermic peak intensity ratio: A tangent to each curve is drawn at the points where the differential values of the curve before and after the peak top and bottom of the peak are maximum and minimum, and the temperature difference between each tangent and the baseline intersection is ΔT, and per unit weight ΔH / ΔT (Figs. 2 and 7 to 10), where ΔH is the height from the baseline to the peak top of the sample (mW / mg is the value obtained by dividing the measured peak height by the weight of the measurement sample). ΔH, ΔT
Of a specific example). That is, the fact that this value is large indicates that the peak is sharp.

The hydrocarbon wax used in the present invention includes (i) a low molecular weight alkylene polymer obtained by radical polymerization of alkylene under a high pressure or a Ziegler catalyst under a low pressure, and (ii) thermal decomposition of a high molecular weight alkylene polymer. A specific component is extracted from a material such as a synthetic hydrocarbon obtained by hydrogenating a distillation residue of a hydrocarbon obtained by the Arge method from a synthesis gas consisting of an alkylene polymer obtained by (iii) carbon monoxide and hydrogen. Fractionated hydrocarbon wax is used. Hydrocarbon wax is fractionated by a press crystallization method, a solvent method, and a fractional crystallization method utilizing vacuum distillation. That is, the low molecular weight components are removed by these methods, the low molecular weight components are extracted, and the low molecular weight components are further removed.

The hydrocarbon as a base is synthesized by a reaction of carbon monoxide and hydrogen using a metal oxide catalyst (often two or more multi-component system), for example, the gintol method or the hydrocol method ( Hydrocarbons with up to several hundred carbons (finally hydrogenated and used as the target product) obtained by the Arge method (using a fixed catalyst bed) where a large amount of waxy hydrocarbons can be obtained. Or a hydrocarbon obtained by polymerizing an alkylene such as ethylene with a Ziegler catalyst is preferable because it is a saturated long-chain linear hydrocarbon with few branches and small size. In particular, a hydrocarbon wax synthesized by a method that does not depend on the polymerization of alkylene is preferable because of its structure and molecular weight distribution that facilitates separation. The preferred range in the molecular weight distribution of the hydrocarbon wax used in the present invention is the number average molecular weight (M
n) is preferably 550 to 1200, more preferably 600 to 1000, and the weight average molecular weight (M
w) is preferably 800 to 3600, more preferably 900 to 3000, and Mw / Mn is 3
It is preferably not more than 2.5, more preferably not more than 2.5, still more preferably not more than 2.0. Further, the molecular weight is 700 to 2400 (preferably the molecular weight is 750 to 200).
It is preferable that a peak exists in the region of 0, particularly preferably the molecular weight of 800 to 1600). By having such a molecular weight distribution, it is possible to give the toner favorable thermal characteristics. That is, when the molecular weight is smaller than the above range, it is likely to be excessively affected by heat, and when the paper is passed through the MICR reader / sorter, the rubbing with the magnetic head easily causes the MICR characters to be blurred, and at the same time, the magnetic head is contaminated. Easy to do. When the molecular weight is larger than the above range, the fixing property is deteriorated and, as a result, MICR characters may be missing when the paper is passed through a MICR reader / sorter, which is not preferable.

Another physical property of the hydrocarbon wax used in the present invention is that the density at 25 ° C. is 0.9.
It is preferably 5 (g / cm ³ ) or more, and the penetration is preferably 1.5 (10 ^-1 mm) or less,
It is more preferably 1.0 (10 ^-1 mm) or less. If it deviates from these ranges, it is liable to change at low temperatures and the MIC is generated when the paper is passed through the MICR reader / sorter.
Blurring of the R character is likely to occur, and at the same time the magnetic head may be contaminated.

Further, the above hydrocarbon wax has a temperature of 140 ° C.
The melt viscosity in is preferably 100 cP or less, more preferably 50 cP or less, still more preferably 20 cP or less. If the melt viscosity exceeds 100 cP, the plasticity and releasability become poor, and MI
MICR when the paper is passed through a CR leader / sorter
Characters are liable to be blurred and the magnetic head of MICR reader / sorter is easily contaminated.

Furthermore, the above-mentioned hydrocarbon wax preferably has a softening point of 130 ° C. or lower, more preferably 120 ° C. or lower. Its softening point is 130 ° C
If it exceeds, the temperature at which the releasability works particularly effectively becomes high,
When the paper is passed through a MICR reader / sorter, the release effect is not sufficiently exerted and MICR characters are liable to be blurred.

Further, the above hydrocarbon wax preferably has an acid value of less than 2.0 mgKOH / g, more preferably less than 1.0 mgKOH / g. If it exceeds this range, the interfacial adhesion with the binder resin, which is one of the components constituting the toner, is large, and the phase separation during melting tends to be insufficient, so that it is difficult to obtain good releasability. MI
When the paper is passed through the CR reader / sorter, the characters are easily scratched and the magnetic head of the MICR reader / sorter is easily contaminated.

The content of these hydrocarbon waxes is
It is preferably used within 20 parts by weight with respect to 100 parts by weight of the binder resin, and more preferably 0.5 to 10 parts.
It is effective to use parts by weight.

In the present invention, the molecular weight distribution of the hydrocarbon wax is determined by gel permeation chromatography (G
PC) under the following conditions.

(GPC measurement conditions) Device: GPC-150
C (Waters Co.) Column: GMH-HT 30 cm 2 series (manufactured by Tosoh Corp.) Temperature: 135 ° C. Solvent: o-dichlorobenzene (0.1% aiol added) Flow rate: 1.0 ml / min Sample: 0.15% sample 0.4 ml injection

The molecular weight calibration curve prepared by the monodisperse polystyrene standard sample is used to calculate the molecular weight of the sample measured under the above conditions. In addition, Mark-Hou
It is calculated by converting to polyethylene using a conversion formula derived from the wink viscosity formula.

The penetration of waxes in the present invention is J
It is a value measured according to IS K-2207. Specifically, it is a numerical value representing the penetration depth in units of 0.1 mm when a needle having a conical tip with a diameter of about 1 mm and an apex angle of 9 ° is penetrated with a constant load. The test conditions in the present invention are a sample temperature of 25 ° C., a load of 100 g, and a penetration time of 5 seconds.

Further, in the present invention, the melt viscosity is a value measured using a Brookfield type viscometer, and the conditions are a measurement temperature of 140 ° C., a shear rate of 1.32 rpm and a sample of 10 ml.

The acid value is the number of mg of potassium hydroxide required to neutralize the acid groups contained in 1 g of the sample (JI
According to SK5902). Density is JIS K at 25 ℃
6760 and the softening point are values measured according to JIS K2207.

Further, in the present invention, the hydrocarbon wax is DS measured by the following characteristic differential scanning calorimeter.
In the C curve, the onset temperature of the endothermic peak is 50 to 9 with respect to the endothermic peak during temperature increase and the exothermic peak during temperature decrease.
It is in the range of 0 ° C., at least one endothermic peak P1 is in the temperature range of 90 to 120 ° C., and the maximum exothermic peak at the time of cooling is in the peak temperature of the endothermic peak P1 ± 9 ° C. This is one of the characteristics, and the above-mentioned object can be achieved by combining with a magnetic body having specific magnetic characteristics described later.

At the time of temperature rise, changes when heat is applied to the wax can be seen, and endothermic peaks due to wax transition and melting are observed. When the onset temperature of the endothermic peak at the time of temperature rise is within the range of 50 to 90 ° C, excellent releasing effect is exhibited, and MICR characters are faint or missing even when repeatedly passed through the MICR reader / sorter. Moreover, it does not easily contaminate the magnetic head of the MICR reader / sorter.

The peak onset temperature during this temperature rise is
If the temperature is less than 50 ° C, the change temperature of the wax is too low,
MICR when you pass through the MICR leader / sorter
Characters are liable to be blurred, and the magnetic head of MICR reader / sorter is easily contaminated.

If the onset temperature of this peak exceeds 90 ° C., the temperature change of the wax is too high and the MIC
MICR characters are likely to be missing when they are passed through the R reader / sorter.

Further, the hydrocarbon wax used in the present invention is in the range of 90 to 120 ° C., preferably 95 to 1 ° C.
It is characterized in that an endothermic peak at the time of temperature rise exists in the range of 20 ° C, more preferably in the range of 97 to 115 ° C. That is, when the wax melts in this temperature range, a releasing effect is exhibited, and MICR characters are less likely to be faint or missing even when repeatedly passed through the MICR reader / sorter. It is hard to contaminate the head.

When the temperature of the endothermic peak at the time of temperature rise exists only below 90 ° C., it is shown that the plasticizing effect by melting of the wax is exhibited from a low temperature and the mechanical strength of the binder resin is remarkably lowered. In this case, the release effect is exhibited when the paper is passed through the MICR reader / sorter, but the mechanical strength of the binder resin is lowered, so that MICR characters may be faint when rubbing against the magnetic head of the MICR reader / sorter. It is apt to occur and at the same time pollutes the magnetic head, which is not preferable.

The endothermic peak at the time of temperature increase may exist in the region exceeding 120 ° C. However, when the endothermic peak temperature exists only in the region exceeding 120 ° C., the melting temperature of the wax is It's too high, and MICR characters can be easily released from the paper.
When the paper is passed through the sorter, MICR characters are apt to be lost due to rubbing against the magnetic head, and as a result, the magnetic head is easily contaminated. Here, when the endothermic peak below 90 ° C. becomes the maximum peak, the same behavior as when there is an endothermic peak only in this region is exhibited, so an endothermic peak may exist in this region, but in that case, It must be smaller than the endothermic peak in the range of 90 to 120 ° C.

When the temperature is lowered, changes in the wax during cooling and the state at room temperature can be seen, and exothermic peaks associated with the solidification, crystallization and transition of the wax are observed. The exothermic peak at the time of cooling is the maximum exothermic peak due to the solidification and crystallization of the wax. The existence of an endothermic peak due to melting at the time of temperature rise near the exothermic peak temperature indicates that the wax is more homogeneous in terms of physical properties such as crystal structure and molecular weight distribution. In the above, the difference is preferably 9 ° C. or less, preferably 7 ° C. or less, and more preferably 5 ° C. or less. That is, by reducing this difference, the wax has a sharp melt property, that is,
It is hard at low temperatures, melts quickly when melting, and a large decrease in melt viscosity occurs, resulting in an excellent release effect.
MICR characters are less likely to be faint or missing even when repeatedly passed through the MICR reader / sorter.
Furthermore, it is hard to contaminate the magnetic head of MICR reader / sorter. Further, in the present invention, the maximum exothermic peak temperature of the hydrocarbon wax is 85 to 115 ° C., preferably 9
It is preferably in the range of 0 to 110 ° C.

The DSC measurement of the wax is based on the case of the above-mentioned toner, and the definition of each temperature is defined as follows.

Endothermic peak: Onset temperature of peak: The lowest temperature at which the differential value of the curve becomes maximum. Therefore, the definition is different from the onset temperature in the case of toner.

Peak temperature: Peak top temperature Exothermic peak: Peak temperature: Maximum peak peak top temperature The content of these hydrocarbon waxes is preferably within 20 parts by weight with respect to 100 parts by weight of the binder resin. It is effective to use it in 0.5 to 10 parts by weight, more preferably 0.5 to 10 parts by weight, and it may be used in combination with other waxes.

In the present invention, the structure of the magnetic material used in combination with the above-mentioned magnetic toner having the specific thermal characteristic or the magnetic toner containing the hydrocarbon wax having the specific thermal characteristic will be described.

The magnetic material according to the present invention has an average particle diameter of 0.1 to 0.1.
The average particle size is preferably 0.6 μm, and more preferably the average particle size is 0.15 to 0.4 μm. In the present invention, the average particle size of the magnetic substance is determined by taking a sample in a magnified photograph at a magnification of 20,000 using a scanning electron microscope and randomly measuring the long-axis value of 100 to 200 particles and averaging the measured values. It is calculated by calculating the value.

The magnetic material used in the magnetic developer of the present invention preferably has a residual magnetization σr in the range of 12 ≦ σr ≦ 30 emu / g in a magnetic field of 10,000 Oersted, more preferably 14 ≦ σr ≦ 28 emu. / G
It is better to be in the range.

When the residual magnetization σr is less than 12 emu / g, the MIC when MICR characters are printed.
The recognition rate of the R leader / sorter is significantly reduced.

Further, when the residual magnetization σr exceeds 30 emu / g, the image density tends to be low and fog is likely to occur, so that the recognition rate is remarkably lowered when MICR characters are printed. The image quality is extremely low even when general printing is performed.

In the magnetic material according to the present invention, the coercive force Hc
Is 130 in a magnetic field of 10,000 Oersted
It is preferably in the range of ≦ Hc ≦ 300 oersteds, and more preferably in the range of 140 ≦ Hc ≦ 280 oersteds.

When the coercive force Hc is less than 130 oersted, the image density is high, but on the other hand, the fine line reproducibility is poor and the recognition rate is lowered when MICR characters are printed, which is preferable. Absent. Coercive force Hc is 300
If it exceeds, it becomes difficult to uniformly apply the magnetic developer onto the developing sleeve, which is not preferable because the image density is lowered or the density becomes uneven.

In the present invention, the magnetic toner is preferably 40 to 1 with respect to 100 parts by weight of the binder resin.
It is preferable to contain 20 parts by weight, more preferably 50 to 110 parts by weight.

The magnetic material used in the present invention is produced by synthesizing by a wet method using an aqueous solution containing Fe ²⁺ , that is, ferrous sulfate as a raw material, and then oxidizing and reducing at a temperature of 200 ° C. or higher. Those that have been processed are preferred. For more information,
After being synthesized by the above-mentioned wet method, it is heated and oxidized at a temperature of 200 ° C. or higher, and then heated and reduced. The heating and oxidation is performed at 500 to 900 ° C. by passing an oxidizing gas such as air. , Then heat reduction, 250-5
It is preferable to carry out aeration with a reducing gas such as hydrogen and / or carbon monoxide at 50 ° C.

In the magnetic developer of the present invention, a load control agent is blended with toner particles (internal addition) or mixed with toner particles (external addition).
It is preferable to use.

Examples of the positive charge control agent that can be used in the present invention include modified products of nigrosine and fatty acid metal salts; tributylbenzylammonium-1-hydroxy-4-naphthostrphonate, tetrabutylammonium tetrafluoroborate, etc. Quaternary ammonium salt of
Dibutyltin oxide, dioctyltin oxide,
Diorgano tin oxides such as dicyclohexyl tin oxide; diorgano tin borates such as dibutyl tin borate, dioctyl tin borate and dicyclohexyl tin borate; can be used alone or in combination of two or more. Among these, charge control agents such as nigrosine and quaternary ammonium salts are particularly preferably used.

Further, the general formula,

[0083]

[Outer 1] _{R 1 = H, CH 3 R} 2, R 3: a single polymer or the above-mentioned such styrene monomer (preferably C ₁ -C ₄₎ substituted or unsubstituted alkyl group represented by acrylic acid ester, methacrylic A copolymer with a polymerizable monomer such as an acid ester can be used as a positive charge control agent, and in this case, these charge control agents are
It also has a function as (all or part of) a binder resin.

Examples of the negative charge control agent that can be used in the present invention include, for example, metal complexes or salts of monoazo dyes;
A metal complex or salt of salicylic acid, alkylsalicylic acid, dialkylsalicylic acid or naphthoic acid is preferably used.

The above charge control agent (which does not act as a binder resin) is preferably used in the form of fine particles. In this case, the number average particle size of this charge control agent is
Specifically, it is preferably 4 μm or less, more preferably 3 μm.
m or less is good.

When internally added to the toner, such a charge control agent is preferably added in an amount of 0.1 to 100 parts by weight of the binder resin.
It is preferable to use 10 to 10 parts by weight, more preferably 0.1 to 5 parts by weight.

The magnetic developer of the present invention preferably contains a hydrophobic silica fine powder.

The silica fine powder referred to here is anhydrous silicon dioxide (silica), other than aluminum silicate, sodium silicate, potassium silicate, magnesium silicate,
Any silicate such as zinc silicate can be applied.

Among the above silica fine powders, the specific surface area by nitrogen adsorption measured by the BET method is 70 to 300 m ² / g.
Those in the range of give good results. Magnetic toner 10
The silica fine powder is preferably 0.2 to 1.
It is preferable to use 6 parts by weight, more preferably 0.4 to 1.4 parts by weight.

When the magnetic toner used in the present invention is used as a positively chargeable magnetic toner, toner wear prevention,
As the silica fine powder added to prevent the surface of the sleeve from being soiled, it is preferable to use positively chargeable silica fine powder, rather than being negatively charged, without impairing the charging stability.

As the method for obtaining the positively chargeable silica fine powder, the above-mentioned untreated silica fine powder is treated with a silicone oil having an organo group having at least one nitrogen atom in the side chain, or a nitrogen-containing silica powder. There is a method of treating with the above silane coupling agent, or a method of treating with both of them.

When the magnetic toner used in the present invention is used as a negatively chargeable magnetic toner, silica fine powder having a triboelectric charge amount of −100 μc / g to −300 μc / g is preferably used. If the amount of triboelectric charge of the fine silica powder is less than −100 μc / g, the amount of triboelectric charge of the developer itself is reduced, and the humidity characteristics are deteriorated. If a fine silica powder having a triboelectric charge amount of more than -300 μc / g is used, it accelerates the memory of the developer carrier and is more susceptible to silica deterioration and the like, which impairs durability characteristics. BET specific surface area of silica fine powder is 3
00m ² / g finer ones than less addition effect to the developer, those coarse than 70m ² / g is large existence probability as educt, likely to become cause of black spots due to silica segregation or agglomerates.

The tribo value of silica fine powder is measured by the following method. That is, 0.2 g of silica fine powder and 200 g of silica fine powder left overnight in an environment of a temperature of 23.5 ° C. and a humidity of 60% RH
Carrier iron powder having a main particle size of up to 300 mesh and not coated with resin (for example, EFV / 3 manufactured by Nippon Iron Powder Co., Ltd.)
00) 9.8 g was precisely weighed under the above environment, and about 50
c. c. Mix thoroughly in a jar with a polyethylene lid having a volume of (hold in your hand and shake up and down about 50 times for about 20 seconds).

Next, as shown in FIG. 15, about 0.5 g of the mixture is put into a metal measuring container 32 having a 400-mesh screen 33 at the bottom, and a metal lid 34 is placed on it. At this time, the total weight of the measuring container 32 is weighed and set as W ₁ (g). Next, in the suction device 31 (at least the portion in contact with the measurement container 32 is an insulator), suction is performed from the suction port 37, and the air volume control valve 36
By adjusting the pressure of the vacuum gauge 35 to 250 mmHg.
In this state, suction is sufficiently performed to remove silica by suction. The potential of the electrometer 39 at this time is V (volt). Here, 38 is a capacitor, and the capacitance is C (μF). The weight of the entire measuring container after suction is weighed and is W ₂ (g). The triboelectric charge amount (μc / g) of this silica is calculated by the following formula.

Triboelectric charge amount = CV / (W ₁ -W ₂ ) The magnetic toner used in the present invention may be mixed with additives as required. As the colorant, conventionally known dyes and pigments can be used, and the binder resin 100 is usually used.
You may use 0.5-20 weight part with respect to weight part. Other external additives in the magnetic developer of the present invention include, for example, a lubricant such as zinc stearate, an abrasive such as cerium oxide and silicon carbide, a fluidity-imparting agent such as aluminum oxide, an anti-caking agent, or the like. A conductivity-imparting agent such as carbon black or tin oxide can be used.

In order to prepare the magnetic developer according to the present invention, magnetic powder and a vinyl-based or non-vinyl-based thermoplastic resin, a pigment or dye as a coloring agent, a charge control agent, and other additives as required. Is thoroughly mixed with a mixer such as a ball mill, and then melted, kneaded and kneaded with a heat kneader such as a heating roll, kneader, or extruder to make the resins or pigments compatible with each other. Can be dispersed or dissolved, cooled and solidified, then pulverized and strictly classified to obtain the insulating magnetic toner according to the present invention.

Further, with reference to FIG. 16, an electrophotographic apparatus and apparatus unit using the magnetic developer of the present invention will be described.

The surface of the photoconductor is negatively charged by the primary charger (charging means) 702, and light image exposure (latent image forming means) 705 is performed.
(Slit exposure / laser beam scanning exposure) forms a digital latent image by image scanning, and a component held in a developing device (developing means) 709 including a developing sleeve 704 containing a magnetic blade 711 and a magnet 714. The latent image is reverse-developed with a magnetic insulating developer 710. Photosensitive drum (photosensitive member) 70 in the developing section
An alternating bias, a pulse bias and / or a DC bias is applied by the bias applying means 712 between the first conductive substrate and the developing sleeve 704. When the transfer paper P is conveyed and reaches the transfer portion, a secondary charging device (transfer means) 703 charges the back surface of the transfer paper P (the surface opposite to the photosensitive drum side) to form a developed image on the surface of the photosensitive drum. The (toner image) is electrostatically transferred onto the transfer paper P. Photosensitive drum 7
The transfer paper P separated from 01 is subjected to a fixing process by the heating and pressure roller fixing device 707 in order to fix the toner image on the transfer paper P.

The one-component type developer remaining on the photosensitive drum after the transfer step is removed by a cleaning device (cleaning means) 708 having a cleaning blade. The photosensitive drum 701 after cleaning is destaticized by the erase exposure 706, and the process starting from the charging process by the primary charger 702 is repeated again.

The electrostatic image carrier (photosensitive drum) has a photosensitive layer and a conductive substrate and moves in the direction of the arrow. The non-magnetic cylindrical developing sleeve 704, which is a toner carrier, rotates so as to move in the same direction as the surface of the electrostatic image carrier in the developing section. Inside the non-magnetic cylindrical sleeve 704, a multi-pole permanent magnet (magnet roll) which is a magnetic field generating means is arranged so as not to rotate. The one-component insulating magnetic developer 710 in the developing unit 709 is applied on the non-magnetic cylindrical surface, and friction between the surface of the sleeve 704 and the toner particles gives the toner particles negative triboelectric charge, for example. Further, by arranging a magnetic doctor blade 711 made of iron close to the surface of the cylinder (interval 50 μm to 500 μm) and facing one magnetic pole position of the multi-pole permanent magnet, the thickness of the developer layer is reduced (30 μm to 30 μm). 300 μm) and uniformly regulated, and the electrostatic charge image carrier 1 and the toner carrier 7 in the developing section are controlled.
A developer layer thinner than the gap 04 is formed so as not to contact. By adjusting the rotation speed of the toner carrier 704, the surface speed of the sleeve is made substantially equal to or close to the speed of the electrostatic image holding surface. Instead of iron as the magnetic doctor blade 711, a permanent magnet may be used to form the opposing magnetic poles. An AC bias or a pulse bias may be applied by the bias means 712 between the toner carrier 704 and the electrostatic image holding surface in the developing section. This AC bias f is 200-
It may be 4,000 Hz and Vpp of 500 to 3,000 V.

Upon transfer of the toner particles in the developing portion, the toner particles are transferred to the electrostatic image side by the action of the electrostatic force of the electrostatic image holding surface and the AC bias or the pulse bias.

Instead of the magnetic doctor blade 711,
The layer thickness of the developer layer may be regulated by pressing with an elastic blade made of an elastic material such as silicone rubber, and the developer may be applied onto the developer carrier.

The electrophotographic apparatus is constructed by integrally combining a plurality of components such as the above-mentioned photosensitive member, developing means, cleaning means and the like as an apparatus unit, and this unit can be detachably attached to the apparatus main body. It may be configured to.
For example, the developing unit and the photoconductor may be integrally supported to form a unit, which is a detachable single unit in the apparatus body, and may be detachable by using a guide unit such as a rail of the apparatus body. At this time, the device unit may be configured to include a charging unit and / or a cleaning unit.

When the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L is reflected light or transmitted light from an original, or an original is read out and converted into a signal, and a laser beam scans an LED by this signal. This is performed by driving the array, driving the liquid crystal shutter array, or the like.

A method of recognizing a magnetic ink symbol using the magnetic developer of the present invention will be described.

FIG. 17 shows an apparatus used in the magnetic ink symbol recognition method of the present invention, in which 1 is a hopper for accommodating the recording paper P and 2 is a conveying means having rollers 2a, 2b and 2c. Reference numeral 3 is a writing head as a magnetism imparting means for imparting magnetism to the toner image on the recording paper, and 4 is a reading head as a magnetic reading means for reading the imparted magnetism.

A recording paper P having an ink symbol (on-as-character) formed of magnetic toner as shown in FIG.
Is from the hopper 1 to the rollers 2a, 2b and 2 of the conveying means 2.
The magnetic property is imparted to the ink symbol by the writing head 3 after being conveyed by c, and the waveform of the magnetism imparted to the ink symbol is read by the reading head 4.
The ink symbol is recognized depending on whether the waveform is proper or not.

The present invention will be specifically described below based on examples, but these do not limit the present invention in any way. In the formulations of Examples, "parts" and "%" indicate "parts by weight" and "% by weight" unless otherwise specified.

[0109]

【Example】

(Preparation of Waxes A to H) Hydrocarbon waxes A to H used in the present invention were prepared as follows.

A hydrocarbon wax synthesized by the Arge process was used as wax F (comparative example), and wax A was prepared from this wax.
(Invention), Wax B (Invention) and Wax C (Invention) were obtained by fractional crystallization.

The hydrocarbon synthesized by the Arge process was oxidized to obtain wax G (comparative example).

Ethylene was low-pressure polymerized using a Ziegler catalyst to obtain a wax H (comparative example) having a relatively low molecular weight.
Wax D (invention) from which low molecular weight components were removed to some extent by fractional crystallization was obtained.

A wax I (comparative example) having a higher molecular weight than the polymerization in the synthesis of wax H was obtained, and by fractional crystallization,
Wax E (invention) was obtained by extracting the low molecular weight components.

DSC of Waxes A to H obtained above
The characteristics, molecular weight distribution and various physical properties are shown in Tables 1 to 3.

(Preparation of Magnetic Material A) A magnetic material was synthesized by a wet method using ferrous sulfate as a raw material, heated and oxidized by passing air at 750 ° C. for 2 hours, and then heated at 350 ° C. with hydrogen gas and nitrogen gas. The magnetic substance A shown in Table 4 was prepared by aerating the gas mixed with the above for 3 hours to heat and reduce.

(Magnetic Materials B and C) Magnetic materials B and C shown in Table 4 were prepared by a wet method using ferrous sulfate as a raw material.

[0117]

[Table 1]

[0118]

[Table 2]

[0119]

[Table 3]

[0120]

[Table 4]

Example 1 Styrene-acrylic copolymer 100 parts by weight Magnetic material A 50 parts by weight (residual magnetization σr = 16.8 emu / g, coercive force in magnetic field of average particle size 0.24 μm, 10,000 oersteds) Hc
= 189 Oersted) Wax A 5 parts by weight Chromium complex of monoazo dye 1 part by weight The above mixture is melt-kneaded in a twin-screw extruder heated to 130 ° C., and the cooled kneaded product is coarsely pulverized by a hammer mill, and coarsely pulverized. Is finely pulverized with a jet mill, and the finely pulverized product obtained is classified with a fixed wall type air classifier, and a fine and coarse powder is obtained with a multi-division classifier (Elbow Jet classifier manufactured by Nittetsu Mining Co., Ltd.) that utilizes the Coanda effect. Were strictly classified at the same time to obtain a black fine powder (magnetic toner 1) having a volume average diameter of 12.3 μm.

With respect to 100 parts by weight of the above-mentioned magnetic toner, 0.
The magnetic developer (1) according to the present invention was obtained by adding 5 parts by weight of the negatively chargeable silica fine powder and mixing them well.

The DSC measurement results of this magnetic toner are shown in Table 5, the DSC curve of the magnetic toner 1 when the temperature is raised is shown in FIG. 1, and the DSC curve when the temperature is lowered is shown in FIG.

Next, Canon laser beam printer L
Using BP-8II, the above magnetic developer (1) was set in the apparatus unit to perform image formation. As a result, a clear image was obtained. When 1000 sheets of MICR characters were printed according to the description of JIS C 6251-1980,
The obtained image was excellent in fine line reproducibility. This 100
Commercially available MICR reader / sorter (I
Magnetic properties were imparted to MICR characters printed by using BM 3890 type machine), and the magnetism of the characters was read to examine the correctness rate (misreading rate) of magnetic reading.
A good result of 8% was obtained. MICR character faintness, missing, and MI after passing through MICR reader / sorter
No contamination of the magnetic head of the CR reader / sorter was observed. The results are shown in Table 6.

The fine line reproducibility of the image was judged as follows. MI according to JIS-C6251-1980
CR characters are printed, and as shown in FIG.
The magnetic signal strength of the (US) symbol was measured to obtain a signal waveform as shown in FIG. The fine line reproducibility was measured by the obtained waveform.

The image density was measured using a Macbeth reflection densitometer with the average density of 10 image samples.

The accuracy rate of magnetic reading was calculated according to the following formula.

[0128]

[Outside 2]

(Examples 2 to 5) Magnetic toners 2 to 5 were prepared in the same manner as in Example 1 except that waxes B to E were used, and magnetic developers (2) to (5) was prepared. Table 5 shows the DSC measurement results of the magnetic toners 2 to 5.

Further, each of the magnetic developers (2) to (5) was passed through a MICR reader / sorter in the same manner as in Example 1. The results are shown in Table 6.

Comparative Examples 1 to 3 Comparative magnetic toners 1 to 3 were prepared in the same manner as in Example 1 except that the waxes F to I were used, and the magnetic developers (6) were prepared in the same manner. ) To (8) were prepared. Table 5 shows the DSC measurement results of each of the comparative magnetic toners 1 to 3.

Further, each of the magnetic developers (6) to (8) was passed through a MICR reader / sorter in the same manner as in Example 1. The results are shown in Table 6.

Comparative Example 4 A comparative magnetic toner 4 was prepared in the same manner as in Example 1 except that no wax was used, and a magnetic developer (9) was prepared in the same manner. Table 5 shows the DSC measurement results of this comparative magnetic toner 4.
This endothermic peak is derived from the binder resin and is also found in other magnetic developers. Further, this magnetic developer (9) was passed through a MICR reader / sorter in the same manner as in Example 1. The results are shown in Table 6.

Comparative Example 5 A comparative magnetic toner 5 was prepared in the same manner as in Example 1 except that the magnetic material A was replaced with the magnetic material B, and the magnetic developer (10) was prepared in the same manner. Was prepared. Table 5 shows the DSC measurement results of this comparative magnetic toner 5. Further, the magnetic developer (10) was passed through a MICR reader / sorter in the same manner as in Example 1. The results are shown in Table 6.

Comparative Example 6 A comparative magnetic toner 6 was prepared in the same manner as in Example 1 except that the magnetic material A was replaced with the magnetic material C, and the magnetic developer (11) was prepared in the same manner. Was prepared. Table 5 shows the DSC measurement results of this comparative magnetic toner 6. Further, the magnetic developer (11) was passed through a MICR reader / sorter in the same manner as in Example 1. The results are shown in Table 6.

(Comparative Example 7) The magnetic material A was replaced with the magnetic material B,
Further, a comparative magnetic toner 7 was prepared in the same manner as in Example 1 except that a wax was not used, and a magnetic developer (12) was prepared in the same manner. Table 5 shows the DSC measurement results of this comparative magnetic toner 7. Further, the magnetic developer (12) was added in the same manner as in Example 1 to the MICR reader /
I passed the paper through the sorter. The results are shown in Table 6.

[0137]

[Table 5]

[0138]

[Table 6] * ₁ ○: No fading of characters.

Δ: There is slight blurring of characters, but there is no problem in practical use.

X: There is a blur of characters and there is a problem in practical use. * ₂ ○: No character is missing.

Δ: There are some missing characters, but there is no problem in practical use.

X: There is a character missing and there is a problem in practical use. * ₃ ○: No dirt on the head.

Δ: There is dirt on the head, but there is no practical problem.

X: There is a problem in practical use because the head is dirty. * ₄ ○: The signal waveform was appropriate, and the visually visible on-us symbol was printed well.

Δ: The signal waveform was almost proper, and the visually recognized on-state symbol was printed almost satisfactorily.

X: The signal waveform was disturbed, the visually recognized on-us symbol was crushed and printed, or there were many scatterings and the reproducibility of fine lines was poor.

[0147]

INDUSTRIAL APPLICABILITY According to the present invention, by containing a specific hydrocarbon wax in a magnetic developer, it is possible to provide the magnetic developer with favorable thermal characteristics. Depending on the combination, the following excellent effects are exhibited.

The present invention can provide a magnetic developer and a magnetic ink symbol recognition method using the magnetic developer, in which MICR characters are not faded or missing even when repeatedly passed through an MICR reader / sorter.

The present invention can provide a magnetic developer which does not contaminate the magnetic head of the MICR reader / sorter even if it is repeatedly passed through the MICR reader / sorter, and a magnetic ink symbol recognition method using the magnetic developer. .

The present invention also provides a toner image excellent in resolution, gradation and fine line reproducibility even in an image forming apparatus for forming a latent image by a digital image signal and developing the latent image by a reversal development method. It is possible to provide a magnetic developer capable of forming an ink and a method for recognizing a magnetic ink symbol using the magnetic developer.

The present invention can provide a magnetic developer exhibiting an excellent recognition rate when used for MICR printing using an electrophotographic printer, and a magnetic ink symbol recognition method using the magnetic developer.

In addition, the present invention can provide a magnetic developer whose recognition rate does not decrease even when repeatedly passed through an MICR reader / sorter, and a magnetic ink symbol recognition method using the magnetic developer.

The present invention is excellent in fine line reproducibility and resolution, and M
It is possible to provide a magnetic developer that faithfully reproduces the ICR character according to its standard and a magnetic ink symbol recognition method using the magnetic developer.

[Brief description of drawings]

FIG. 1 is a diagram showing a DSC curve of a magnetic developer 1 of the present invention when the temperature is raised.

FIG. 2 is a diagram showing a DSC curve when the temperature of the magnetic developer 1 of the present invention is lowered.

FIG. 3 is a diagram showing an endothermic peak portion of a DSC curve at the time of heating.

FIG. 4 is a diagram showing an endothermic peak portion of a DSC curve at the time of heating.

FIG. 5 is a diagram showing an endothermic peak portion of a DSC curve at the time of heating.

FIG. 6 is a diagram showing an endothermic peak portion of a DSC curve at the time of heating.

FIG. 7 is a diagram showing an exothermic peak portion of a DSC curve when the temperature is lowered.

FIG. 8 is a diagram showing an exothermic peak portion of a DSC curve when the temperature is lowered.

FIG. 9 is a diagram showing an exothermic peak portion of a DSC curve when the temperature is lowered.

FIG. 10 is a diagram showing an exothermic peak portion of a DSC curve when the temperature is lowered.

FIG. 11 is a graph of D of the wax A according to the present invention when the temperature is raised.
It is a figure which shows a SC curve.

FIG. 12 is a graph D of the wax A according to the present invention when the temperature is lowered.
It is a figure which shows a SC curve.

FIG. 13 shows DS of wax F (comparative example) during heating.
It is a figure which shows a C curve.

FIG. 14 shows DS of wax F (comparative example) at the time of cooling.
It is a figure which shows a C curve.

FIG. 15 is an explanatory diagram of an apparatus for measuring the triboelectric charge amount of toner in triboelectric charge amount measurement.

FIG. 16 is a schematic configuration diagram showing an electrophotographic apparatus using the magnetic developer of the present invention.

FIG. 17 is a schematic configuration diagram for explaining a magnetic ink symbol recognition method of the present invention.

FIG. 18 is a diagram showing “on-as” symbols printed as MICR characters to evaluate fine line reproducibility.

FIG. 19 is a diagram showing a signal waveform of the “on-as” symbol of FIG. 18.

[Explanation of symbols]

 1 Hopper 2 Conveying means 2a, 2b, 2c Roller 3 Magnetism imparting means 4 Magnetic reading means P Recording paper 31 Suction machine 32 Measuring container 33 Conductive screen 34 Lid 35 Vacuum gauge 36 Air flow control valve 37 Suction port 38 Condenser 39 Electrometer 701 Photoconductor 702 Charging means 703 Transfer means 704 Toner carrier 705 Latent image forming means 706 Erase exposure 707 Heating / pressurizing roller fixing device 708 Cleaning means 709 Developing means 710 Magnetic developer 711 Magnetic blade 712 Bias applying means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G03G 9/08 365

Claims (6)

[Claims] 1. A magnetic developer having a magnetic toner containing at least a binder resin, a magnetic substance and a hydrocarbon wax, wherein the magnetic toner has a temperature rise in a DSC curve measured by the following characteristic differential scanning calorimeter. Regarding the endothermic peak at the time, the onset temperature at the endothermic peak is 105 ° C. or lower, and the endothermic peak temperature is 10
0 to 120 ° C., with respect to the exothermic peak at the time of cooling, the exothermic peak temperature is in the range of 62 to 75 ° C., and the exothermic peak intensity ratio is 5 × 10 ⁻³ or more. The magnetic material has a remanent magnetization (σ _r ) of 12 to 30 emu / in a magnetic field of 10,000 Oersted.
and the coercive force (Hc) is 130 to 30
A magnetic developer having a range of 0 oersted. 2. The magnetic developer is used for printing characters used in a magnetic ink symbol identification system for reading information by magnetic characters using a magnetic reader. Magnetic developer. 3. A magnetic developer having a magnetic toner containing at least a binder resin, a magnetic material and a hydrocarbon wax, wherein the magnetic toner has a temperature rise in a DSC curve measured by the following characteristic differential scanning calorimeter. As for the endothermic peak at the time and the exothermic peak at the time of cooling, the onset temperature of the endothermic peak is in the range of 50 to 90 ° C., and there is at least one endothermic peak P1 in the region of the temperature of 90 to 120 ° C. Peak temperature ± 9
The maximum exothermic peak at the time of temperature decrease is satisfied within the range of ° C, and the magnetic substance has a remanent magnetization (σ _r ) in the range of 12 to 30 emu / g and a coercive force (in the magnetic field of 10,000 oersteds). Hc) is in the range of 130 to 300 oersteds. 4. The magnetic developer according to claim 3, wherein the magnetic developer is used for printing characters used in a magnetic ink symbol identification system for reading information by magnetic characters using a magnetic reader. Magnetic developer. 5. A magnetic ink symbol for printing a magnetic ink symbol on a recording material using a magnetic developer, applying magnetism to the printed magnetic ink symbol, and reading and identifying the magnetism of the magnetized magnetic ink symbol. In the recognition method, the magnetic developer has a magnetic toner containing at least a binder resin, a magnetic substance and a hydrocarbon wax, and the magnetic toner has a DSC measured by the following characteristic differential scanning calorimeter.
In the curve, regarding the endothermic peak at the time of temperature increase, the onset temperature at the endothermic peak is 105 ° C. or lower, and the endothermic peak temperature is 10
The exothermic peak at the time of cooling is in the range of 0 to 120 ° C., the exothermic peak temperature is in the range of 62 to 75 ° C., and the exothermic peak intensity ratio is 5 × 10 ⁻³ or more, and In a magnetic field of 10,000 Oersted,
A method for recognizing a magnetic ink symbol, wherein the remanent magnetization (σ _r ) is in the range of 12 to 30 emu / g and the coercive force (Hc) is in the range of 130 to 300 Oersted. 6. A magnetic ink symbol for printing a magnetic ink symbol on a recording material using a magnetic developer, imparting magnetism to the printed magnetic ink symbol, and reading and identifying the magnetism of the magnetized magnetic ink symbol. In the recognition method, the magnetic developer has a magnetic toner containing at least a binder resin, a magnetic substance and a hydrocarbon wax, and the magnetic toner has a DSC measured by the following characteristic differential scanning calorimeter.
In the curve, regarding the endothermic peak at the time of temperature rise and the exothermic peak at the time of temperature decrease, the onset temperature of the endothermic peak is in the range of 50 to 90 ° C, and there is at least one endothermic peak P1 in the region of the temperature of 90 to 120 ° C. Peak temperature of the endothermic peak P1 ± 9
The maximum exothermic peak at the time of temperature decrease is satisfied within the range of ° C, and the magnetic substance has a remanent magnetization (σ _r ) in the range of 12 to 30 emu / g and a coercive force (in the magnetic field of 10,000 oersteds). Hc) is in the range of 130 to 300 oersteds.