JP3363458B2 - Magnetic developer, apparatus unit, electrophotographic apparatus, and magnetic ink symbol identification method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic developer used in electrophotography, electrostatic printing, electrostatic recording, etc., an apparatus unit having the magnetic developer, and an electrophotographic apparatus having the magnetic developer. .

The present invention further provides magnetic ink symbol identification (Ma).
genetic Ink Character Reco
magnetic developer suitable for printing characters having magnetism used in a gnition system, an apparatus unit having the magnetic developer, an electrophotographic apparatus having the magnetic developer, and identification of a magnetic ink symbol using the magnetic developer. Regarding the method.

The present invention further relates to an electrophotographic image forming method, wherein a latent image is expressed by a unit pixel, and a unit latent image is expressed by a binary or on / off binary value or a finite gradation. And a device unit having the magnetic developer, an electrophotographic device having the magnetic developer, and a method of identifying a magnetic ink symbol using the magnetic developer.

[0004]

2. Description of the Related Art Generally, an electrophotographic system exposes a document image and exposes the reflected light to a latent image carrier,
A method of obtaining a latent image is performed. In this method, since the reflected light of the original is directly used as an image signal, the potential of the electrical latent image continuously changes (hereinafter referred to as an analog latent image).

On the other hand, recently, there has been commercialized a method of converting reflected light of an original into an electric signal, processing the signal, and then performing exposure based on the signal. This method can easily perform high-magnification enlargement and reduction as compared with a method using an analog latent image, and can further capture an image signal in a computer and output it together with other information. This method has various uses as described above, but when the image signal is handled as analog, the signal amount becomes huge, so the image is divided into pixel units (hereinafter referred to as dots), and the exposure amount for each divided pixel is increased. Digital processing is required to determine.

When a latent image is digitized, each dot needs to be developed more accurately than an analog latent image. Therefore, a developer that can faithfully develop pixels with a high development rate. Is required.

In the case of developing a digital latent image, the deviation of the surface potential of the latent image at the time of forming the latent image is larger than that of the analog latent image, so that the developer transport section and the latent image carrier such as the photosensitive drum. It is necessary to perform development even in the latent image portion where the potential difference between them is small.

In an image in which an image and a non-image are repeated every dot, the developability of the developer is particularly important. Therefore, when a developer developed as a developer for an analog latent image is diverted to a digital latent image system, the development for each dot is insufficient especially in a print pattern in which the image / non-image is repeated every dot. However, the phenomenon that the dots become small or the image is not developed at all occurs, and as a whole, the image density tends to be light and the characters tend to be faint. This phenomenon becomes remarkable in a developer (hereinafter referred to as a magnetic developer) having a magnetic toner containing a magnetic material whose developer charge amount tends to be small.

It is considered that this is because the magnetic developer has a portion where the magnetic substance is exposed on the surface of the magnetic toner particle, and the surface that can contribute to charging is reduced. Since the surface exposure amount of the magnetic material changes depending on the amount of the magnetic material contained in one magnetic toner, the distribution of the charge amount of the developer becomes wider than that of other developers having no magnetic toner particles.

Therefore, when the magnetic developer is used in a digital latent image system, magnetic toner particles having a low triboelectric charge amount of
Character fading due to accumulation in the developing device is likely to occur, and improvement thereof is desired.

Further, in recent years, as image forming apparatuses such as electrophotographic copying machines have become widespread, their applications have been widespread. Against this background, as an application field of electrophotographic printers, magnetic ink symbol identification Magnetic
Ink Character Recognition
A character printer used for a system (hereinafter, simply referred to as MICR) has been devised.

The MICR system is mainly a magnetic reader having a magnetizing head and a reading head for printing information such as issuing bank, amount of money, and account number on a check, a bill, etc. with magnetic ink for classification and sorting at a clearing house. It is a system devised to effectively perform using. Conventionally, offset printing using magnetic ink was the mainstream,
Commercial transactions such as personal checks and bills are becoming more active, and a small MICR character printing machine (hereinafter simply referred to as MIC
The demand for R encoders) is increasing.

The conventional small MICR encoder is
Impact printers that applied the thermal transfer method were the mainstream, but most of these are single-function machines that print only MICR characters and cannot be used for general document production, so improvements are required. There is.

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.

On the other hand, when the electrophotographic printer is applied to the MICR encoder, if the conventionally known magnetic developer is used as it is, the accuracy rate (recognition rate) of the magnetic reading by the MICR reader / sorter is offset printing or impact printer. Compared with the case of printing MICR characters using, it is extremely low and not practical.

The number of securities printed with MICR characters is 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 4 types of symbols.
The branch code, account number and amount are printed.

In order to improve the recognition rate by the MICR reader / sorter, it is required that the shape and size of the printed MICR characters be reproduced with high accuracy. For this reason, it is necessary for the characters to be reproduced finely and faithfully without being crushed or broken.

In order to achieve a high recognition rate in printing MICR characters with an electrophotographic printer, it is necessary to use a magnetic developer capable of reproducing characters with high accuracy. Further, it is desired to use a magnetic developer containing a specific magnetic material exhibiting magnetic characteristics different from those of magnetic materials used in conventional magnetic developers.

That is, it is necessary to use a magnetic developer having excellent fine line reproducibility due to its high developing characteristics.

Further, a magnetic material having a relatively large residual magnetization σr is desired.

Further, as a magnetic toner for MICR, it exhibits a good triboelectrification property like a magnetic developer of a general electrophotographic printer, and it is on a developer carrier (hereinafter referred to as a sleeve) of a developing machine. It is required to be applied uniformly. In order to satisfy this condition, the shape and magnetic permeability of the magnetic material contained in the magnetic developer are also important.

Japanese Patent Publication No. 59-7379 discloses a long axis /
Includes cobalt-substituted ferric oxide powder having a minor axis ratio of 1 to 5, remanent magnetization of 10 to 20 emu / g, and coercive force of 150 to 4
Although a magnetic toner of 50 Oersted has been proposed, when an image is formed using the magnetic toner, it is difficult to uniformly apply the toner layer on the sleeve, the triboelectric chargeability is poor, and the image density is low. Is low and inferior in sharpness.

Japanese Patent Laid-Open No. 63-108354 discloses that the major axis / minor axis ratio is 1 to 1.5 and the magnetic permeability is 3.
Insulating magnetic capsule toners containing spherical magnetic powder of 80 to 6.00 have been proposed. JP-A-59-20
Japanese Patent No. 4846 proposes a magnetic toner containing ferromagnetic fine powder having a maximum magnetic permeability of 3.95 to 5.50. When these toners are used, the image density is high, which is preferable, but further improvement is required in order to meet more severe demands for resolution and compatibility with reversal development methods.

[0025]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, a magnetic developer, an apparatus unit having the magnetic developer, an electrophotographic apparatus having the magnetic developer, and the magnetic developer. The present invention provides a magnetic ink symbol identification method using.

That is, the object of the present invention is to provide a magnetic developer having good fine line reproducibility and resolution and which is preferably used for developing a digital latent image, an apparatus unit having the magnetic developer,
An object of the present invention is to provide an electrophotographic apparatus having the magnetic developer and a magnetic ink symbol identifying method using the magnetic developer.

Further, an object of the present invention is to provide a magnetic developer capable of increasing the image density, an apparatus unit having the magnetic developer, an electrophotographic apparatus having the magnetic developer, and a magnetic ink using the magnetic developer. It is to provide a symbol identification 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, an apparatus unit having the magnetic developer, an electrophotographic apparatus having the magnetic developer, and a magnetic ink symbol identifying method using the magnetic developer.

Further, an 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, an apparatus unit having the magnetic developer, and the magnetic developer. It is an object of the present invention to provide an electrophotographic apparatus having the same and a magnetic ink symbol identifying method using the magnetic developer.

Still another object of the present invention is to provide a magnetic developer which is excellent in fine line reproducibility and resolution and can be faithfully reproduced according to the standard even when MICR characters are printed, an apparatus unit having the magnetic developer, An object of the present invention is to provide an electrophotographic apparatus having a magnetic developer and a magnetic ink symbol identifying method using the magnetic developer.

Still another object of the present invention is to provide a magnetic developer which gives a clear image with less fog and does not reduce the recognition rate even when MICR characters are printed, an apparatus unit having the magnetic developer, and An object of the present invention is to provide an electrophotographic apparatus having a magnetic developer and a magnetic ink symbol identifying method using the magnetic developer.

Another object of the present invention is to provide a magnetic developer having a narrow triboelectric charge distribution and a large triboelectric charge amount, an apparatus unit having the magnetic developer, an electrophotographic apparatus having the magnetic developer, and the magnetic developer. A magnetic ink symbol identification method using a developer is provided.

Another object of the present invention is to use a magnetic developer capable of further increasing the image density, an apparatus unit having the magnetic developer, an electrophotographic apparatus having the magnetic developer, and the magnetic developer. A magnetic ink symbol identification method is provided.

Still another object of the present invention is to provide a magnetic developer having a better recognition rate when used for MICR printing using an electrophotographic printer, an apparatus unit having the magnetic developer, and the magnetic developer. To provide an electrophotographic apparatus having a developing agent and a magnetic ink symbol identifying method using the magnetic developer.

Still another object of the present invention is MICR.
Magnetic developer whose recognition rate does not decrease even when repeatedly passed through a leader / sorter, an apparatus unit having the magnetic developer, an electrophotographic apparatus having the magnetic developer, and a magnetic ink symbol identifying method using the magnetic developer Is to provide.

Still another object of the present invention is MICR.
A magnetic developer that does not cause MICR characters to drop off or become faint even when passed through a reader / sorter, a device unit including the magnetic developer, an electrophotographic device including the magnetic developer, and the magnetic developer. It is to provide a magnetic ink symbol identification method used.

Still another object of the present invention is MICR.
A magnetic developer that does not cause MICR characters to drop off or become faint even when passed through a reader / sorter, a device unit including the magnetic developer, an electrophotographic device including the magnetic developer, and the magnetic developer. It is to provide a magnetic ink symbol identification method used.

Still another object of the present invention is to make the coating of the magnetic developer on the developing sleeve uniform and to disperse the magnetic material uniformly in the magnetic toner of the magnetic developer.
A homogenous magnetic developer having magnetic characteristics and triboelectrification properties, an apparatus unit including the magnetic developer, an electrophotographic apparatus including the magnetic developer, and a magnetic ink symbol identifying method using the magnetic developer. .

Still another object of the present invention is to provide a magnetic developer which interacts well with the permanent magnet in the developing sleeve and which can appropriately control the triboelectric charge amount of the magnetic developer. An apparatus unit having the same, an electrophotographic apparatus having the magnetic developer, and a magnetic ink symbol identifying method using the magnetic developer.

Still another object of the present invention is to provide a magnetic developer having a magnetic material that can be uniformly dispersed in a magnetic toner of the magnetic developer, an apparatus unit having the magnetic developer, and the magnetic developer. It is an object of the present invention to provide an electrophotographic apparatus having the same and a magnetic ink symbol identifying method using the magnetic developer.

[0041]

The magnetic developer of the present invention is a magnetic developer having magnetic toner particles having a magnetic substance, the magnetic substance containing silicon element and aluminum element. The residual magnetization (σr) is 12 to
30 emu / g and magnetic permeability (μ) of 2.0 to 4.0
And the following formula

[Outside 5] The above-mentioned object is achieved by the fact that the variation coefficient calculated by is 20% or more.

The apparatus unit of the present invention comprises an electrostatic charge image carrier for carrying an electrostatic charge image, developing means for developing the electrostatic charge image, and charging for charging the surface of the electrostatic charge image carrier. Means and / or a cleaning means for contacting the surface of the electrostatic charge image bearing member to clean the surface of the electrostatic charge image bearing member are integrally supported to form a unit,
In a device unit which is detachably attached to the device body, the developing means contains silicon element and aluminum element, and has a residual magnetization (σr) of 12 to 30e.
a magnetic substance having a magnetic toner particle having a magnetic substance of mu / g, a magnetic permeability (μ) of 2.0 to 4.0, and a coefficient of change calculated by the above formula of 20% or more. By having a developer,
To achieve the above objectives.

The electrophotographic apparatus of the present invention comprises an electrostatic charge image carrier for carrying an electrostatic charge image, a charging means for charging the surface of the electrostatic charge image carrier, and a charged electrostatic charge image carrier. A latent image forming means for forming an electrostatic charge image on the surface, a developing means for developing the electrostatic charge image formed on the surface of the electrostatic charge image carrier to form a developed image, and a transfer material for transferring the developed image. In an electrophotographic apparatus having a transfer means for transferring to, the developing means contains a silicon element and an aluminum element, and has a residual magnetization (σr) of 12 to 30 emu /
g, magnetic permeability (μ) is 2.0 to 4.0, and a magnetic developer having magnetic toner particles having a magnetic material having a coefficient of change calculated by the above formula of 20% or more. The above-mentioned object is achieved by having the following features.

The magnetic ink symbol identifying method of the present invention prints a magnetic ink symbol on a recording material by using a magnetic developer, imparts magnetism to the printed magnetic ink symbol, and imparts magnetism to the magnetic ink symbol. In the method of identifying a magnetic ink symbol for reading and identifying magnetism, the magnetic developer contains silicon element and aluminum element, and the residual magnetization (σ
r) is 12 to 30 emu / g, magnetic permeability (μ) is 2.0 to 4.0, and a magnetic material having a magnetic material having a coefficient of change of 20% or more calculated by the above formula The above object is achieved by including toner particles.

As a result of earnest studies, the inventors of the present invention have found that the magnetic substance contained in the magnetic toner particles of the magnetic developer contains a silicon element and an aluminum element. It has been found that the triboelectrification property is improved and the distribution of the charge amount of the magnetic developer can be sharpened.

Therefore, the magnetic developer of the present invention is characterized by having magnetic toner particles having a magnetic material containing silicon element and aluminum element.

The magnetic developer of the present invention has the above-described structure and is improved in the ability to faithfully reproduce even the fine lines of the latent image formed on the photosensitive member. Excellent reproducibility and excellent gradation and resolution.

Further, the magnetic developer of the present invention has the above-mentioned constitution, and when MICR characters are printed, MIC
It can be accurately reproduced according to the standard of R character, and MI
A high recognition rate is obtained when the paper is passed through the CR reader / sorter.

In the present invention, the silicon element contained in the magnetic material of the magnetic developer is preferably 0.1 to 1.0% by weight, and more preferably 0.15% by weight based on the magnetic material in terms of SiO _2. .About.0.9% by weight is preferable, and similarly, the aluminum element is 0.1% based on the magnetic substance in terms of Al ₂ O _3.
Is preferably 1.0 to 1.0% by weight, more preferably 0.15 to
0.9% by weight is preferred.

In the present invention, the silicon element and the aluminum element can be added during and / or after the synthesis of the magnetic substance by the wet method, and in the case where the heat oxidation treatment and the heat reduction treatment are further performed after the wet synthesis. , Can also be added at that stage.

In the magnetic material according to the present invention, when the silicon element converted to SiO ₂ is less than 0.1% by weight based on the magnetic material, a magnetic developer having a large triboelectric charge amount can be obtained, When the charge amount distribution becomes wider and the charging performance is likely to change due to long-term use and environmental changes such as temperature and humidity, when the silicon element converted to SiO ₂ exceeds 1.0 wt% based on the magnetic substance. , The distribution of the triboelectric charge amount becomes narrow, but it is difficult to obtain a magnetic developer having a large triboelectric charge amount.

In the magnetic material according to the present invention, the aluminum element converted to Al ₂ O ₃ is 0.1% by weight based on the magnetic material.
When it is less than 1.0, it is difficult to obtain a magnetic developer having a large triboelectric charge amount, and when the aluminum element converted to Al ₂ O ₃ exceeds 1.0% by weight based on the magnetic substance, the triboelectric charge amount is large. Although a magnetic developer can be obtained, the charge distribution tends to be wide, and the toner may be developed even in the non-image area on the photoconductor, which tends to result in images with a lot of fog, fine line reproducibility, and It is difficult to obtain a magnetic developer with excellent tonality.

In the magnetic material according to the present invention, SiO ₂
In the case where the weight ratio of the silicon element converted to the above and the aluminum element converted to Al ₂ O ₃ is 20: 1 to 1:20, more preferably 1:10 to 1:10. , And more preferably 1: 4 to 4: 1.

When the weight ratio of the elemental silicon and the elemental aluminum is less than 20: 1, the effect of increasing the image density due to the addition of the elemental aluminum is less, and the ratio of aluminum is less than 1:20. When the number of elements becomes large, when the magnetic material obtained by the wet method at the time of manufacturing the magnetic material is heated to be oxidized and reduced,
It is not preferable because it may lead to stagnation.

The magnetic substance according to the present invention contains silicon element and aluminum element. Such a magnetic substance is prepared by a wet method using ferrous sulfate as a raw material, and is prepared by adding, for example, sodium silicate and, for example, aluminum hydroxide during and / or after the synthetic reaction. be able to.

In the magnetic material according to the present invention, the residual magnetization σ
r is 12 ≦ σ in 10,000 Oersted magnetic field
The range of r ≦ 30 emu / g is preferable, and the range of 14 ≦ σr ≦ 28 emu / g is more preferable.

When the residual magnetization σr is less than 12 emu / g, the MICR reader / sorter recognition rate tends to decrease when MICR characters are printed, and when general printing is performed, It is difficult to obtain a magnetic developer with excellent fine line reproducibility and gradation.

When the residual magnetization σr exceeds 30 emu / g, the image density tends to be low and fog is likely to occur. Therefore, when MICR characters are printed, the recognition rate tends to be low, Even when general printing is performed, the image quality tends to be low.

In the magnetic material according to the present invention, the coercive force Hc
Is 10,000 ≦ in a magnetic field of 10,000 Oersted.
It is preferable that Hc ≦ 300 oersted,
More preferably, it may be in the range of 150 ≦ Hc ≦ 280 oersted.

When the coercive force Hc is less than 130 Oersted, the image density is high, but the reproducibility of fine lines tends to be low. Therefore, the recognition rate is likely to be low when MICR characters are printed. . Also, the coercive force Hc is 300
When it exceeds the above, it is difficult to uniformly apply the magnetic developer on the developing sleeve, and the image density is lowered or
Density unevenness is likely to occur.

According to the study by the present inventors, when the magnetic material according to the present invention has a relatively large residual magnetization σr, the magnetic permeability μ and the developing characteristics of the magnetic developer correspond well. I found that

Further, it was also found that the magnetic permeability μ corresponds well to the accuracy rate of reading by the MICR reader / sorter when MICR characters are printed.

In the magnetic material according to the present invention, the magnetic permeability μ is preferably in the range of 2.0 ≦ μ ≦ 4.0, and more preferably 2.5 ≦ μ ≦ 3.8.

When the magnetic permeability μ exceeds 4.0, it is possible to uniformly apply the magnetic developer on the developing sleeve, but the interaction with the permanent magnet in the developing sleeve is weak and the magnetic developing is It is difficult to properly control the triboelectric charge amount of the agent, and the toner easily scatters in the image area.
When ICR characters are printed, the recognition rate tends to decrease.

When the magnetic permeability μ is less than 2.0, the interaction with the permanent magnet in the developing sleeve is strong and, as a result, it is difficult to properly control the triboelectric charge amount of the magnetic developer, and the image Since the density tends to be low, the recognition rate tends to decrease when MICR characters are printed.

A magnetic substance having a remanent magnetization of 12 to 30 emu / g in the above 10,000 Oersted magnetic field, a coercive force Hc of 130 to 300 Oersted in the 10,000 Oersted magnetic field, and a permeability μ of 2.0 to 4.0. As described above, the ferromagnetic material having high magnetic properties adheres to the developing sleeve by a strong magnetic force with the magnet in the developing sleeve, so that the developing efficiency for the electrostatic image carrier tends to decrease.

However, the magnetic material of the present invention contains the silicon element and the aluminum element to improve the triboelectric chargeability of the developer and to sharpen the charge amount distribution to improve the developing characteristics. It is possible to cover the deterioration of the developing characteristics when a ferromagnetic material having high characteristics is used.

The magnetic material according to the present invention is the above-mentioned 10,000.
12-30 emu / g remanent magnetization at 0 Oersted field, 130 at 10,000 Oersted field
To 300 Oersted coercive force Hc and 2.0 to 4.0
It has higher magnetic characteristics than the magnetic material generally used for the magnetic developer for electrophotography, such as the magnetic permeability μ.

The high magnetic properties of such a magnetic substance cannot be possessed by a magnetic substance synthesized by a usual wet method using ferrous sulfate as a raw material.

A magnetic material having such high magnetic properties is obtained by using the magnetic material synthesized by the above wet method.
Under high temperature conditions such as 0 to 900 ° C, oxidation is performed in the presence of oxygen, for example, in air to α-Fe ₂ O ₃ , and then the temperature is lowered to 250 to 450 ° C to reduce hydrogen gas and nitrogen gas (inert gas). It can be prepared by reducing in a mixed gas with a gas).

In the present invention, the magnetic properties of the magnetic substance refer to values measured by VSMP-1 manufactured by Toei Industry Co., Ltd. In measuring the magnetic properties, the magnetic substance is 0.1 to 0.15 g. Is precisely weighed with a direct balance having a sensitivity of about 1 mg to prepare a sample, and the measurement is performed at a temperature of around 25 ° C. The external magnetic field at the time of magnetic property measurement is 10,000 Oersted,
The sweep speed for drawing the hysteresis loop can be set to 10 minutes.

The magnetic substance used in the magnetic developer of the present invention is 1.2 to 2.5 g / cm ³ , more preferably 1.3 to 2.5 g / cm ³ .
It has a compacted apparent density of 2.0 g / cm ³ and is 5 to 30.
ml / 100g, preferably 10-28ml / 100g
It preferably has a linseed oil absorption.

1.2 to 2.5 of compacted apparent density of magnetic material
The value of g / cm ³ is so large that a usual untreated magnetic material cannot be satisfied. The magnetic substance preferably used in the present invention can be prepared by crushing the magnetic substance so as to have the above-mentioned specific compacting apparent density and specific linseed oil absorption amount. Means used for crushing the magnetic material include a mechanical crusher equipped with a high-speed rotor for crushing the powder, and a load for dispersing or crushing the powder. A pressure disperser equipped with a roller can be used.

When the agglomerates of the magnetic substance are crushed by using a mechanical crusher, the impact force of the rotor is likely to be excessively applied to the primary particles of the magnetic substance, and the primary particles themselves are destroyed. As a result, fine powder of magnetic material is easily generated. When a magnetic material crushed by this mechanical pulverizer is used as a raw material for toner, the triboelectric charging characteristics of the toner deteriorate due to the presence of fine powder of magnetic particles. Therefore, the toner image density is likely to decrease due to the decrease in the triboelectric charge amount of the toner.

On the other hand, a pressure disperser equipped with a weighting roller such as a fred mill is preferable in terms of the efficiency of crushing the aggregates of the magnetic material and the suppression of the generation of the fine powder magnetic material.

It can be understood that the tap density and the oil absorption of the magnetic substance indirectly indicate the shape of the magnetic substance, the surface state of the magnetic substance, and the amount of the aggregate of the magnetic substance. When the compacted apparent density of the magnetic substance is less than 1.2 g / cm ³ , many magnetic substance aggregates are present, indicating that the crushing treatment of the magnetic substance is substantially insufficient. . Therefore,
When a magnetic substance having a compacted apparent density of less than 1.2 g / cm ³ is used, it is difficult for the magnetic substance to be uniformly dispersed in the binder resin, and uneven distribution of the magnetic substance is caused when MICR characters are printed. The recognition rate tends to decrease.

The compacted apparent density of the magnetic material is 2.5 g / cm.
If it exceeds ³ , the aggregates of the magnetic substance are excessively crushed, and the magnetic substances stick to each other due to pressure, resulting in the formation of pellets of the magnetic substance. However, the content of the magnetic substance is different, and when MICR characters are printed, the recognition rate also tends to decrease.

Even when the value of the linseed oil absorption amount of the magnetic material deviates from the above upper limit and lower limit, the same phenomenon as in the case of the solid apparent density is likely to occur.

In the present invention, the compacted apparent density (pack bulk density) of the magnetic substance is described using a powder tester manufactured by Hosokawa Micron Co., Ltd. and a container attached to the powder tester. The value measured according to the written procedure.

In the present invention, the amount of linseed oil absorption of the magnetic substance is a value measured according to the method described in JIS K 5101-1978 (pigment test method).

According to the study by the present inventors, when the residual magnetization (σr) has a relatively large value as compared with the conventional magnetic material like the above-mentioned magnetic material, the individual magnetic particles are The fluctuation range of magnetic properties is also expected to be relatively large.

On the other hand, in the case of a magnetic developer, it is known that the content of the magnetic material varies depending on the particle size. In other words, it suggests that the magnetic developer may have different magnetic properties depending on its particle size.

Therefore, in the case of a magnetic developer in which it is important to strictly satisfy a certain magnetic property as in the present invention,
It is preferable to control the state of existence of the magnetic substance in the binder resin. This indicates that not only the magnetic substance is uniformly dispersed in the binder resin, but also the filling state is important.

The present inventors have found that the filling state of the magnetic material in the binder resin is strongly influenced by the particle size distribution of the magnetic material.

It has been found that the magnetic material according to the present invention achieves the above preferable filling state when the coefficient of change showing the particle size distribution has a certain specific numerical value.

The change coefficient of the magnetic material here is a numerical value calculated by the following formula.

[0087]

[Outside 2] (In the formula, x represents the average particle size of the magnetic substance, and σ represents the standard deviation of the particle size distribution.)

Further, in the magnetic developer, in order to further improve the fine line reproducibility and make the line image clearer, narrowing the charge amount distribution is one solution.

Conventionally, in order to narrow the distribution of the amount of charge in the magnetic developer, it has been known that the magnetic substance is uniformly dispersed as an effective means. However, like the magnetic material according to the present invention, when the silicon element and the aluminum element are contained on the surface and inside (preferably in a specific ratio), it is not always necessary to disperse them uniformly.

According to the study by the present inventor, in the case of the magnetic material according to the present invention, the distribution of the charge amount of the magnetic developer is determined in the same manner as the magnetic characteristics when the above-mentioned change coefficient has a specific numerical value. We have found that it can be made narrower.

In the magnetic material according to the present invention, the coefficient of change is 20% or more, preferably 20 to 50%, more preferably 25 to 45%. When the coefficient of change is less than 20%, the dispersion of the magnetic substance in the magnetic developer is generally equalized and gives a preferable result. However, in the case of the magnetic substance having high magnetic properties according to the present invention, According to the studies made by the present inventors, the coating of the magnetic developer on the developing sleeve tends to be non-uniform, and the homogeneity of triboelectrification tends to be deteriorated.

Further, when the coefficient of change exceeds 50%, the uniformity of the dispersed state of the magnetic material inside the magnetic developer deteriorates, and the magnetic properties such as remanent magnetization of the magnetic developer and the homogeneity of triboelectricity are reduced. Tends to decrease.

A method of adjusting the change coefficient to 20 to 50% can be carried out by controlling the conditions of the above-mentioned crushing treatment.

In the magnetic material according to the present invention, the specific surface area is preferably 5.0 to 13.0 m ² / g in terms of BET specific surface area measured by the nitrogen gas adsorption method, and more preferably 6. It is a case where it becomes 0 to 10.0 m ² / g.

The BET specific surface area can be measured by the nitrogen gas adsorption method using a commercially available measuring device, for example, Autosorb 1 (manufactured by Quantum Chemicals).

Generally, the BET specific surface area and the average particle size are
Almost corresponding. Therefore, the magnetic substance according to the present invention preferably has an average particle size of 0.1 to 0.6 μm, more preferably 0.15 to 0.4 μm.
Those with m are better. In the present invention, the average particle size of the magnetic material is determined by using a scanning electron microscope to magnify the sample at a magnification of 2
It is determined by taking a magnified photograph at 10,000 times, randomly measuring the major axis values of 100 to 200 particles, and calculating the average value. Further, by simultaneously measuring the minor axis value, the major axis / minor axis value can be obtained.

In the magnetic material according to the present invention, the major axis / minor axis ratio is preferably 1.0 to 1.5, and more preferably 1.0 to 1.4.

In the magnetic developer of the present invention, when the average particle diameter of the magnetic material is less than 0.1 μm, the dispersibility of the magnetic material in the binder resin becomes poor, and the chargeability of the magnetic developer is made uniform. Or even if the dispersibility in the binder resin is good, the shear modulus before and after the fixing temperature of the magnetic developer is remarkably increased and the fixability is deteriorated.

Further, when the average particle size of the magnetic powder exceeds 0.6 μm, the dispersion in the binder resin is not uniform, the chargeability is not uniform, and the surface of the photoreceptor is significantly damaged. There are cases where it is not preferable.

Therefore, in the magnetic material according to the present invention, when the BET specific surface area is 5.0 to 13.0 m ² / g or the average particle diameter is 0.1 to 0.6 μm. Improves the dispersion of the magnetic material in the binder resin, makes the chargeability of the magnetic developer more uniform, and improves the fixability of the magnetic developer.

When the major axis / minor axis ratio of the magnetic material deviates from 1.0 to 1.5, the adhered state of the magnetic developer on the developing sleeve is non-uniform and the developing characteristics at the time of development are deteriorated, resulting in image deterioration. The concentration tends to decrease. Long axis / short axis ratio is 1.0 to 1.5
Examples of the shape of the magnetic substance include a spherical shape, a hexahedral shape, and an octahedral shape.
For example, a needle shape can be mentioned.

In the magnetic developer of the present invention, the triboelectric charge amount is preferably -5 to -20 μc / g. If the triboelectric charge amount is less than -5 μc / g, the image density tends to be low, which is not preferable. When the toner becomes large, a so-called charge-up phenomenon that hinders proper charging of the toner supplied thereto occurs, and the image density is likely to gradually decrease. This phenomenon is likely to occur when developing a digital latent image, which is the development of a dot latent image, and is more remarkable in a low potential contrast reversal development method using an OPC photoconductor.

The magnetic toner according to the present invention is substantially electrically insulating because it has a triboelectric charge. In particular,
It is preferable that the resistance value when a voltage of 100 V is applied under a pressure of 3.0 kg / cm ² is 10 ¹⁴ Ω · cm or more.

The magnetic material according to the present invention is preferably contained in an amount of 50 to 140 parts by weight, more preferably 60 to 120 parts by weight, based on 100 parts by weight of the binder resin. If the content of the magnetic material is less than 50 parts by weight with respect to 100 parts by weight of the binder resin, the transportability of the magnetic toner on the developer carrying member such as a sleeve tends to decrease, and if it exceeds 140 parts by weight. In addition, the insulating property and heat fixing property of the magnetic toner tend to decrease.

The magnetic substance according to the present invention was 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 are preferable.

The charge amount of the toner in the present invention is 5 g for 1 g of toner and 9 g of iron powder carrier of 200 to 300 mesh.
Place in a 0 cc polyethylene bottle, cover and cover for 20 seconds in an environment of temperature 23 ° C and humidity 60% RH (about 100
A small amount of the mixture which was shaken and stirred by hand is put in a container of the apparatus shown in FIG. 1, and suctioned at a pressure of 250 mmH ₂ O for about 1 minute until the potential is saturated.

From the saturation potential V ₁ , the condenser capacity C ₁ , the weight W ₁ of the container before suction, and the weight W ₂ of the container after suction at this time, the charge amount Q ₁ was calculated by the following formula.

[0108]

[Outside 3]

In the magnetic material according to the present invention, the magnetic permeability μ
Is a value called effective relative permeability. The measurement is obtained by uniformly winding a toroidal magnetic core, applying an appropriate alternating magnetic field, and changing the inductance at that time.

The specific measuring method is as follows.
2.5 ml of an aqueous solution of polyvinyl alele having a binder resin concentration of 5 to 10% by weight is added to g and mixed well, then placed in a ring-shaped mold and molded at a pressure of about 1 ton / cm ² . At this time, it is important to adjust the density of the sample so as to be constant in order to improve the reproducibility of measured values.

Further, the toroidal sample was wound with several tens of turns to prepare a sample for magnetic permeability measurement, and the tuning capacitance was measured with, for example, Yokogawa Hewlett-Packard Co. impedance, gain, phase analyzer. It can be obtained by doing.

A concrete method of calculating the effective relative magnetic permeability will be described below.

The effective relative magnetic permeability is defined by the following equation.

[0114]

[Outside 4]

Here, L ₀ is the inductance of the coil when there is no magnetic material, and L is the inductance of the coil when the magnetic material is inserted. The inductance of the coil when there is no magnetic material is expressed by the following equation.

[0116]

[Outside 5] Therefore, the effective relative permeability is calculated by the following equation.

[0117]

[Outside 6]

Here, μ ₀ is the magnetic permeability (4π × 1) in vacuum.
0 ^-7 ), A is the cross-sectional area of the sample, N is the number of turns of the coil, and I is the average magnetic path length of the sample. Therefore, the effective relative permeability can be obtained by measuring the inductance when the magnetic body is inserted.

In the magnetic material according to the present invention, the content of silicon element can be measured by the following method. About 0.5 to 1 g of a magnetic substance for measuring the content of silicon is precisely weighed and placed in a mold with a diameter of about 5 mm, and about 10 t / cm ²
Apply pressure to mold. Next, the fluorescent X-ray intensity of this magnetic material sample is measured.

At this time, several kinds of samples having known SiO ₂ contents were prepared as standard samples, and the silicon contained in the magnetic material sample was obtained with the relative value to the fluorescent X-ray intensity of these standard samples. It can be measured and quantified as a value obtained by adding the element to SiO ₂ .

[0121]

[Outside 7]

The standard sample of SiO ₂ is JIS
The SiO ₂ content is quantified based on the gravimetric method described in the method for quantifying silicon dioxide of K 1462-1981.

The content of aluminum element in the magnetic material according to the present invention can be measured by the following method. The total amount of a suspension prepared by dispersing about 25 g of a magnetic material in 400 ml of ion-exchanged water in a slurry state in 3 l of ion-exchanged water maintained at a temperature of 45 to 50 ° C. was washed with about 328 ml of ion-exchanged water. .

Next, while maintaining the water temperature at 50 ° C., 1272 ml of special grade hydrochloric acid is added with stirring to dissolve the magnetic substance. If the magnetic substance is dissolved and the solution becomes transparent, the pore size is 0.1μ.
Filter with a membrane filter of m. At this time, the content of the aluminum element in the filtrate is measured by plasma emission spectroscopy (ICP).

In the present invention, the content of the aluminum element thus measured is converted into Al ₂ O ₃ for calculation.

[0126]

[Outside 8]

In the magnetic developer of the present invention, it is preferable to use a load control agent mixed with the toner particles (internal addition) or mixed with the toner particles (external addition). Examples of the positive charge control agent include nigrosine; fatty acid metal salts such as aluminum stearate and modified compounds thereof; tetrabutylbenzyl ammonium-1-hydroxy-4-naphtholsulfonate, tetrabutylammonium tetrafluoroborate such as tetrabutylammonium tetrafluoroborate. Quaternary ammonium salts; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate; used alone or in combination of two or more kinds. be able to. Among these, charge control agents such as nigrosine and quaternary ammonium salts are particularly preferably used.

Further, the general formula

[0129]

[Outside 9] _{R 1: H, CH 3 R} 2, R 3: a single polymer of a monomer represented by a substituted or unsubstituted alkyl group (preferably a C ₁ ~C _4): or styrene as described above, acrylic acid esters, methacrylic A copolymer with a polymerizable monomer such as an acid ester can be used as a positive charge control agent. In this case, these charge control agents also function as (all or part of) the binder resin.

As the negative charge control agent that can be used in the present invention, for example, a metal complex or salt of a monoazo dye; for example, a metal complex or salt of salicylic acid, alkylsalicylic acid, dialkylsalicylic acid or naphthoic acid is preferably used.

The above-mentioned 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 the charge control agent is internally added to the toner particles to form a magnetic developer, such a charge control agent is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin,
It is more preferable to use 0.1 to 5 parts by weight.

When a charge control agent is externally added to toner particles to form a magnetic developer, such a charge control agent is preferably added in an amount of 0.05 to 10 parts by weight based on 100 parts by weight of the binder resin. It is better to use 0.3 to 5 parts by weight.

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

In addition to anhydrous silicon dioxide (silica), silicates such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate and zinc silicate are all applied to the fine silica powder. be able to.

The fine silica powder having a specific surface area by nitrogen adsorption measured by the BET method in the range of 70 to 300 m ² / g gives particularly good results. The amount of the silica fine powder used is preferably 0.2 to 1.6 parts by weight, more preferably 0.4 to 1.4 parts by weight, based on 100 parts by weight of the magnetic toner particles.

When the magnetic developer of the present invention is used as a positively chargeable magnetic developer, silica fine powder added to prevent abrasion of the toner and stain on the surface of the sleeve is not negatively chargeable. It is preferable to use the positively chargeable silica fine powder without impairing the charging stability.

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

When the magnetic developer of the present invention is used as a negatively chargeable magnetic developer, a silica fine powder having a triboelectric charge amount of −100 μc / g to −300 μc / g is preferably used. When the triboelectric charge amount is less than −100 μc / g, the triboelectric charge amount of the developer itself tends to be lowered, and the humidity characteristics are likely to be lowered. When the triboelectric charge amount exceeding -300 μc / g is used, the developer-carrying member memory is promoted, the silica is easily affected by silica deterioration, and the durability characteristics are likely to be deteriorated. Further, fine silica powder having a BET specific surface area smaller than 300 m ² / g has little effect on addition to the developer, and fine silica powder having a BET specific surface area smaller than 70 m ² / g has a high probability of existence as a free substance, resulting in silica segregation and aggregation. It is easy to cause black spots due to objects.

In the present invention, the tribo value of the silica fine powder is measured by the following method. Temperature 23.5 ℃, Humidity 60%
0.2g and 2g of silica fine powder left overnight in RH environment
Carrier iron powder not covered with resin, which has a main particle size of 00 to 300 mesh (for example, EF manufactured by Nippon Iron Powder Co., Ltd.
V200 / 300) 9.8 g is precisely weighed under the above environment,
Approximately 50c. c. Mix well (hand shake approximately 50 times up and down for about 20 seconds) in a jar with a polyethylene lid.

Next, as shown in FIG. 1, about 0.5 g of the mixture is placed in a metallic measuring container 32 having a 400-mesh screen 33 at the bottom, and a metallic lid 34 is placed on it. At this time, the total weight of the measurement container 32 is weighed and set as W ₃ (g). next,
In the suction device 31 (at least the part that is in contact with the measurement container 32 is an insulator), suction air is sucked from the suction port 37
Is prepared and the pressure of the vacuum gauge 35 is set 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 ₂ (volt). Here, 38 is a condenser, and the capacitance is C ₂ (μF). In addition, weigh the entire measuring container after suction by W
₄ (g). Tribo charge of this silica (μc /
g) is calculated by the following formula.

[0142]

[Outside 10]

Additives may be added to the magnetic developer according to the present invention, if necessary. As the colorant, conventionally known dyes and pigments can be used. Usually, the colorant is added in an amount of 0.5 to 2 with respect to 100 parts by weight of the binder resin.
0 parts by weight can be used. Other external additives that can be added to the magnetic developer of the present invention include lubricants such as zinc stearate; cerium oxide,
There are abrasives such as silicon carbide; fluidity-imparting and anti-caking agents such as aluminum oxide; and conductivity-imparting agents such as carbon black, tin oxide.

To prepare a magnetic developer for developing an electrostatic image according to the present invention, a magnetic powder and a vinyl-based or non-vinyl-based thermoplastic resin, a pigment or dye as a colorant, if necessary, a charge After thoroughly mixing the control agent and other additives with a mixer such as a ball mill, melt, knead, and knead the resin with a heat kneader such as a heating roll, kneader, or extruder to make the resins compatible with each other. The insulating magnetic toner particles according to the present invention can be obtained by dispersing or dissolving a pigment or dye in the mixture, cooling and solidifying, crushing and strict classification.

Further, the electrophotographic apparatus and apparatus unit of the present invention will be described with reference to FIG.

The surface of the photosensitive drum (electrostatic image bearing member) 701 is negatively charged by a primary charger (charging means) 702, and an image is formed by light image exposure (latent image forming means: slit exposure / laser beam scanning exposure) 705. A digital latent image is formed by scanning, and the magnetic blade 711 and the magnet 71 are formed.
The latent image is reverse-developed with a one-component insulating magnetic developer 710 held in a developing device (developing means) 709 having a developing sleeve 704 containing four. Alternate bias is applied between the conductive substrate of the photosensitive drum 701 and the developing sleeve 704 in the developing unit by the bias applying unit 712.
A pulse bias and / or a DC bias is applied. When the transfer paper (transfer material) P is conveyed and reaches the transfer portion, the secondary charging device (transfer means) 703 charges the back surface (the surface opposite to the photosensitive drum side) of the transfer paper P, and thus the surface of the photosensitive drum. The developed image above is electrostatically transferred onto the transfer paper P.
The transfer paper P separated from the photosensitive drum 701 is subjected to a fixing process by the heating and pressure roller fixing device 707 so that the toner on the transfer paper P fixes the image.

The one-component 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 701 has a photosensitive layer and a conductive substrate and moves in the direction of the arrow. The non-magnetic cylindrical developing sleeve 704 rotates so as to move in the same direction as the surface of the electrostatic image carrier 701 in the developing section. Developing sleeve 70
A multi-pole permanent magnet (magnet roll), which is a magnetic field generating means, is arranged in the inside of 4 so as not to rotate. The one-component insulating magnetic developer 710 in the developing unit 709 is applied on the surface of the developing sleeve 704, and due to the friction between the surface of the developing sleeve 704 and the magnetic developer, the magnetic developer is, for example, a negative tribo. An electric charge is given. Further, a magnetic doctor blade 711 made of iron is attached to the developing sleeve 7.
Close to the surface of No. 04 (spacing 50 μm to 500 μm),
The developer layer is made thin (30 μm to 300 μm) by arranging it so as to face one magnetic pole position of the multi-pole permanent magnet.
m) and regulate it uniformly to form a developer layer thinner than the gap between the electrostatic charge image carrier 701 and the developing sleeve 704 in the developing section so as not to contact the electrostatic charge image carrier 1.
By adjusting the rotation speed of the developing sleeve 704, the surface speed of the sleeve is made substantially equal to or close to the speed of the surface of the electrostatic image carrier 701. Instead of iron as the magnetic doctor blade 711, a permanent magnet may be used to form the opposing magnetic poles. In the developing unit, the developing sleeve 704 and the electrostatic image carrier 701
An AC bias or a pulse bias may be applied to the surface of the device by the bias applying means 712. This AC bias has an f of 200 to 4,000 Hz and a Vpp of 5
It is preferably from 00 to 3,000V.

When the magnetic developer in the developing portion is transferred, the magnetic developer is transferred to the electrostatic image carrier 701 by the electrostatic force on the surface of the electrostatic image carrier 701 and the action of the AC bias or the pulse bias. .

Instead of the magnetic doctor blade 711,
An elastic blade formed of an elastic material such as silicone rubber may be used to regulate the layer thickness of the developer layer by pressing the elastic blade, and the magnetic developer may be applied onto the developing sleeve.

As the electrophotographic apparatus, a plurality of constituent elements such as the electrostatic image carrier, the developing means and the cleaning means described above are integrally combined to form a single unit. The device unit may be detachable from the main body. For example, the developing unit and the electrostatic image carrier may be integrally supported to form a single unit, and the single unit may be detachably configured by using a guide unit such as a rail of the apparatus main body. At this time, the above device unit may be provided with a charging unit and / or a cleaning unit.

When the electrophotographic apparatus is used as a copying machine or a printer, the latent image forming means L converts the reflected light or transmitted light from the original document or the original document into a signal and scans the laser beam with this signal. This is performed by driving the LED array or the liquid crystal shutter array.

[0153]

EXAMPLES The present invention will be specifically described by the following examples, which do not limit the present invention.

The parts and% in the examples are parts by weight and% by weight, unless otherwise specified.

(Production Example of Magnetic Materials 1 to 3) Using ferrous sulfate as a raw material, a synthetic reaction of a magnetic material was performed by a wet synthesis method of performing an oxidation reaction in an aqueous solution. By adding sodium silicate and aluminum hydride during the synthesis reaction of this magnetic substance, as shown in Table 1, the amount of silicon element in terms of SiO ₂ and the amount of aluminum element in terms of Al ₂ O ₃ are contained. Magnetic bodies 1 to 3 were prepared.

The contents of silicon element and aluminum element in the magnetic material were measured by plasma spectroscopy and fluorescent X-ray analysis.

(Production Example of Magnetic Materials 4 to 6) The above magnetic material 1
~ 3 as a raw material, air was blown for 2 hours at 750 ° C to oxidize the raw material to α-Fe ₂ O _3, and then the temperature was raised to 350 ° C and then hydrogen gas and nitrogen gas were mixed. The magnetic bodies 4 to 6 having the characteristic values shown in Table 1 were prepared by passing gas for 3 hours.

(Production Example of Magnetic Materials 7 to 9) Magnetic materials 4 to 6 were crushed by a fred mill to crush aggregates of the magnetic materials, and magnetic materials having the characteristic values shown in Table 1 were obtained. 7-9
Was prepared.

(Production Example of Magnetic Material 10) Using ferrous sulfate as a raw material, a synthetic reaction of a magnetic material is performed by a wet synthesis method in which an oxidation reaction is performed in an aqueous solution to prepare a magnetic material 10 having the characteristic values shown in Table 1. did.

[0160]

[Table 1]

(Example 1) 60 parts by weight of magnetic material 8 100 parts by weight of styrene-butyl acrylate copolymer (weight average molecular weight: 315,000, styrene / butyl acrylate copolymerization ratio: 82/18) Chromium complex of monoazo dye (negative charge control agent) 0.
5 parts by weight

The above mixture was melt-kneaded with a twin-screw extruder heated to 130 ° C., the cooled kneaded product was coarsely pulverized with a hammer mill, and the coarsely pulverized product was finely pulverized with a jet mill.
The finely pulverized powder obtained was classified by a fixed wall type air classifier to produce classified powder. A fine powder and a coarse powder are strictly and simultaneously removed from the obtained classified powder by a multi-division classifier utilizing the Coanda effect (Elbowjet classifier manufactured by Nittetsu Mining Co., Ltd.) to obtain a black fine powder having a volume average particle diameter of 11.9 μm. (Magnetic toner particles) are obtained. The black fine powder obtained had a value of -7.3 µc / g, when the triboelectric charge was measured after mixing with the iron powder carrier.

The magnetic developer (1) of the present invention was obtained by adding 0.5 parts by weight of negatively chargeable silica fine powder to 100 parts by weight of the above magnetic toner particles and mixing them well.

When the magnetic developer (1) was imaged using a laser beam printer LBP-8 manufactured by Canon, the image density was as high as 1.35 and a clear image with less fog was obtained. According to the description of JIS C 6251-1980, 1000 sheets of MICR characters were printed. M printed with 1000 sheets of printed matter using a commercially available MICR reader / sorter (6780 type machine manufactured by MCR)
When the magnetism of the ICR character was given and the magnetism of the character was read, and the accuracy rate (recognition rate) of the magnetic reading was examined,
Good results were obtained with a recognition rate of 88.8%.

(Example 2) A magnetic developer (2) was prepared in the same manner as in Example 1 except that the magnetic substance 8 not subjected to the crushing process was used in place of the magnetic substance 8. Example 1
When the image is printed in the same manner as above, the image density is 1.30.
And a clear image with high fog can be obtained.
When CR characters were printed and the correctness rate (recognition rate) of magnetic reading was examined, a good result of 84.3% was obtained.

Example 3 A magnetic developer (3) was prepared in the same manner as in Example 1 except that the magnetic substance 9 which had been subjected to the crushing treatment was used in place of the magnetic substance 8. When images were printed out in the same manner as in Example 1, a high image density of 1.35 was obtained, and a clear image with less fog was obtained.
When an R character was printed and the correctness rate (recognition rate) of magnetic reading was examined, a good result of 93.1% was obtained.

(Example 4) A magnetic developer (4) was prepared in the same manner as in Example 1 except that the magnetic substance 6 not subjected to the crushing process was used in place of the magnetic substance 8. Example 1
When the image is printed in the same manner as above, the image density is 1.30.
And a clear image with less fog is obtained.
Correctness rate (recognition rate) of magnetic reading by printing ICR characters
As a result, a good result of 85.9% was obtained.

Example 5 A magnetic developer (5) was prepared in the same manner as in Example 1 except that the crushed magnetic substance 7 was used in place of the magnetic substance 8. When images were printed out in the same manner as in Example 1, the image density was high at 1.35, and clear images with less fog were obtained.
When an R character was printed and the correctness rate (recognition rate) of magnetic reading was examined, a good result of 95.4% was obtained.

(Example 6) A magnetic developer (6) was prepared in the same manner as in Example 1 except that the magnetic substance 8 which was not subjected to the crushing process was used in place of the magnetic substance 8. Example 1
When the image is printed in the same manner as above, the image density is 1.30.
And a clear image with high fog can be obtained.
When CR characters were printed and the correctness rate (recognition rate) of magnetic reading was examined, a good result of 90.8% was obtained.

(Comparative Example 1) A magnetic developer for comparison (1) was prepared in the same manner as in Example 1 except that the magnetic substance 8 which had not been subjected to the crushing process was used in place of the magnetic substance 8. .
When images were printed out in the same manner as in Example 1, the image density was as low as 1.1, which was clearly inferior.
When an R character was printed and the correctness rate (recognition rate) of magnetic reading was examined, it was clearly inferior at 40.6%.

The results of Examples 1 to 6 and Comparative Example 1 are shown in Table 2.

[0172]

[Table 2] * MICR according to JIS-C6251-1980
Characters are printed and as shown in Fig. 3, ON US (ON US)
The magnetic signal strength of the symbol was measured to obtain a signal waveform as shown in FIG. The fine line reproducibility was judged by the obtained waveform. A: The signal waveform was proper, and the visually recognized on-us symbol was satisfactorily printed. B: The signal waveform was almost appropriate, and the visually recognized on-state symbol was printed almost satisfactorily. C: The signal waveform was disturbed, and the visually recognized ass symbol was crushed and printed.

(Production Example of Magnetic Materials 11 to 13) Using ferrous sulfate as a raw material, a synthetic reaction of a magnetic material was performed by a wet synthesis method in which an oxidation reaction was performed in an aqueous solution. By adding sodium silicate and aluminum hydroxide during the synthetic reaction of this magnetic material, a magnetic material containing silicon, an element and an aluminum element was obtained. Using the obtained magnetic material as a raw material, 75
The raw material is oxidized to α-Fe ₂ O ₃ by bubbling air at 0 ° C. for 2 hours, then the temperature is brought to 350 ° C., and then a gas obtained by mixing hydrogen gas and nitrogen gas is bubbled for 3 hours. By doing so, the magnetic materials 11 to 1 having the characteristic values shown in Table 3 are obtained.
3 was prepared.

(Production Example of Magnetic Material 14) Ferrous sulfate was used as a raw material to synthesize a magnetic material by a wet synthesis method in which an oxidation reaction was carried out in an aqueous solution. During the synthetic reaction of this magnetic substance,
By adding sodium silicate, a magnetic material 14 containing the elemental silicon and having the characteristic values shown in Table 3 was prepared.

(Production Example of Magnetic Material 15) Ferrous sulfate was used as a raw material to synthesize a magnetic material by a wet synthesis method in which an oxidation reaction was performed in an aqueous solution. During the synthetic reaction of this magnetic substance,
A magnetic material 15 containing aluminum element and having the characteristic values shown in Table 3 was prepared by adding aluminum hydroxide.

(Production Example of Magnetic Material 16) Using ferrous sulfide as a raw material, a synthetic reaction of a magnetic material is performed by a wet synthesis method in which an oxidation reaction is carried out in an aqueous solution to prepare a magnetic material 16 having the characteristic values shown in Table 3. did.

[0177]

[Table 3]

(Example 7) 60 parts by weight of magnetic substance 11 Styrene-butyl acrylate copolymer (weight average molecular weight: 315,000, styrene / butyl acrylate copolymer weight ratio: 82/18) 1
00 parts by weight · Chromium complex of monoazo dye (negative charge control agent) 0.5
Parts by weight

The above mixture was heated to a temperature of 130 ° C.
Melt kneading with a shaft extruder, crush the cooled kneaded material roughly with a hammer mill, finely crush the coarsely crushed material with a jet mill, and classify the resulting finely crushed powder with a fixed-wall type air classifier to obtain classified powder. Generated. A black fine powder with a volume average particle diameter of 11.2 μm is obtained by precisely and precisely removing fine powder and coarse powder at the same time with a multi-division classifier (elbowjet classifier manufactured by Nittetsu Mining Co., Ltd.) using the Coanda effect. (Magnetic toner particles)
Got The black fine powder obtained had a value of -9.2 μc / g when the triboelectric charge was measured after mixing with the iron powder carrier.

The magnetic developer (7) according to the present invention was obtained by adding 0.5 part by weight of the negatively chargeable silica fine powder to 100 parts by weight of the magnetic toner particles and mixing them well.

When the magnetic developer (7) was imaged using a laser beam printer LBP-8 manufactured by Canon, the image density was as high as 1.3 and a clear image with less fog was obtained. According to the description of JIS C6251-1980, 1,000 sheets of MICR characters were printed. R of the 1,000 prints printed using a commercially available MICR reader / sorter (NCR 6780 type machine)
When magnetism was imparted to the ICR character, the magnetism of the character was read, and the accuracy rate (recognition rate) of magnetic reading was examined. As a result, a good result showing a recognition rate of 94.0% was obtained.

(Embodiment 8) Magnetic material 1 instead of magnetic material 11
A magnetic developer (8) was prepared in the same manner as in Example 7 except that 2 was used. When images were printed out in the same manner as in Example 7, a high image density of 1.3 and a clear image with less fogging was obtained, and MICR characters were printed in the same manner, and the accuracy rate of magnetic reading was corrected. When the (recognition rate) was examined, a good result of 87.5% was obtained.

(Embodiment 9) Magnetic substance 1 instead of magnetic substance 11
A magnetic developer (9) was prepared in the same manner as in Example 7, except that 3 was used. When images were printed in the same manner as in Example 7, a clear image with a high image density of 1.3 and less fog was obtained. Further, MICR characters were printed in the same manner, and the accuracy rate of magnetic reading ( When the recognition rate) was examined, a good result of 92.9% was obtained.

(Comparative Example 2) Magnetic material 1 was used in place of magnetic material 11.
Comparative Magnetic Developer (2) was prepared in the same manner as in Example 7 except that No. 4 was used. When images were printed out in the same manner as in Example 7, the image density was as low as 1.1, which was clearly inferior. Furthermore, MICR characters were printed and the correctness rate (recognition rate) of magnetic reading was examined. Where 34.3
It was clearly inferior.

COMPARATIVE EXAMPLE 3 Magnetic material 1 was used in place of magnetic material 11.
A comparative magnetic developer (3) was prepared in the same manner as in Example 7 except that 5 was used. When images were printed out in the same manner as in Example 7, the image density was 1.2, which was slightly higher than that without aluminum element, but it was still low and not satisfactory for practical use. When the correctness rate (recognition rate) of magnetic reading was examined by printing, the result was 40.1%, which was clearly inferior.

(Comparative Example 4) Instead of the magnetic body 11, the magnetic body 1 was used.
Comparative Magnetic Developer (4) was prepared in the same manner as in Example 7 except that 6 was used. When images were printed out in the same manner as in Example 7, the image density was as low as 1.1, which was clearly inferior. Furthermore, MICR characters were printed and the correctness rate (recognition rate) of magnetic reading was examined. Where 43.6
It was clearly inferior.

The results of Examples 7-9 and Comparative Examples 2-4 are shown in Table 4.

[0188]

[Table 4]

(Production Example of Magnetic Materials 17 to 19) Using ferrous sulfate as a raw material, a synthetic reaction of a magnetic material was performed by a wet synthesis method in which an oxidation reaction was performed in an aqueous solution. A magnetic material containing silicon element and aluminum element was obtained by adding sodium silicate and aluminum hydroxide during the synthetic reaction of this magnetic material. 750 using the obtained magnetic material as a raw material
To oxidize the raw material to α-Fe ₂ O ₃ by bubbling air at ℃ for 2 hours, and then bubbling a mixture of hydrogen gas and nitrogen gas for 3 hours at a temperature of 350 ° C. To prepare a magnetic material. The magnetic material was subjected to a crushing treatment for crushing the agglomeration of the magnetic material using a Fred mill to prepare magnetic materials 17 to 19 shown in Table 5.

(Production Example of Magnetic Material 20) Ferrous sulfate was used as a raw material to synthesize a magnetic material by a wet synthesis method in which an oxidation reaction was performed in an aqueous solution. By adding sodium silicate during this synthesis reaction, the magnetic body 20 shown in Table 5 having a silicon element was prepared.

[0191]

[Table 5]

Example 10 60 parts by weight of magnetic material 17 Styrene-butyl acrylate copolymer (weight average molecular weight: 315,000, styrene / butyl acrylate copolymerization weight ratio: 82/18) 100 parts by weight・ Chromium complex of monoazo dye (negative charge control agent) 0.
5 parts by weight

The above mixture was melt-kneaded with a twin-screw extruder heated to 130 ° C., the cooled kneaded product was coarsely pulverized with a hammer mill, and the coarsely pulverized product was finely pulverized with a jet mill.
The finely pulverized powder obtained was classified by a fixed wall type air classifier to produce classified powder. A fine powder and a coarse powder are precisely and simultaneously removed by a multi-division classifier (Nippon Mining Co., Ltd. elbow jet classifier) using the Coanda effect to classify the obtained classified powder at the same time to obtain a black fine powder having a volume average particle diameter of 12.6 μm. (Magnetic toner particles) are obtained. The black fine powder obtained had a value of -8.3 μc / g when the triboelectric charge was measured after mixing with the iron powder carrier.

The magnetic developer (10) according to the present invention was obtained by adding 0.5 parts by weight of the negatively chargeable silica fine powder to 100 parts by weight of the magnetic toner particles and mixing them well.

When the magnetic developer (10) was imaged using a laser beam printer LBP-8 manufactured by Canon, the image density was as high as 1.35 and a clear image with less fog was obtained. In addition, JIS C6251-1980
According to the above description, 1,000 sheets of MICR characters were printed. The magnetic property of magnetic printing is obtained by applying magnetism to MICR characters printed by using the commercially available MICR reader / sorter (Model 6780 manufactured by NCR Co., Ltd.) with 1,000 sheets of printed matter, and correctness rate of magnetic reading is obtained. When the (recognition rate) was examined, a good result of 94.8% was obtained.

Example 11 A magnetic developer (11) was prepared in the same manner as in Example 10 except that the magnetic substance 18 was used in place of the magnetic substance 17. When images were printed out in the same manner as in Example 10, a high image density of 1.35 was obtained, and a clear image with less fog was obtained.
When ICR characters were printed and the correctness rate (recognition rate) of magnetic reading was examined, a good result of 92.7% was obtained.

(Example 12) A magnetic developer (12) was prepared in the same manner as in Example 10 except that the magnetic material 19 was used in place of the magnetic material 17. When images were printed out in the same manner as in Example 10, a high image density of 1.35 was obtained, and a clear image with less fog was obtained.
When ICR characters were printed and the accuracy rate (recognition rate) of magnetic reading was examined, a good result of 89.4% was obtained.

(Comparative Example 5) Instead of the magnetic body 17, the magnetic body 2 was used.
Comparative developer (5) was prepared in the same manner as in Example 10 except that 0 was used. When images were printed out in the same manner as in Example 10, the image density was as low as 1.1, which was clearly inferior. Furthermore, MICR characters were printed and the accuracy rate (recognition rate) of magnetic reading was examined. Where 44.7
It was clearly inferior.

The results of Examples 10-12 and Comparative Example 5 are shown in Table 6.

[0200]

[Table 6]

(Production Example of Magnetic Materials 21 to 23) Using ferrous sulfate as a raw material, a synthetic reaction of a magnetic material was performed by a wet synthesis method in which an oxidation reaction was performed in an aqueous solution. A magnetic material containing silicon element and aluminum element was obtained by adding sodium silicate and aluminum hydroxide during the synthetic reaction of this magnetic material. 750 using the obtained magnetic material as a raw material
To oxidize the raw material to α-Fe ₂ O ₃ by bubbling air at ℃ for 2 hours, and then bubbling a mixture of hydrogen gas and nitrogen gas for 3 hours at a temperature of 350 ° C. To prepare a magnetic material. The magnetic material was crushed using a Fred mill to crush the aggregation of the magnetic material, and magnetic materials 21 to 23 shown in Table 7 were prepared.

(Production Example of Magnetic Material 24) Using ferrous sulfate as a raw material, a synthetic reaction of a magnetic material was performed by a wet synthesis method in which an oxidation reaction was performed in an aqueous solution. By adding sodium silicate during this synthesis reaction, a magnetic material containing silicon element was obtained. The magnetic material was crushed using a Fred mill to crush the magnetic material to prepare a magnetic material 24 shown in Table 7.

[0203]

[Table 7]

Example 13 60 parts by weight of magnetic material 21 Styrene-butyl acrylate copolymer (weight average molecular weight: 315,000, styrene / butyl acrylate copolymerization weight ratio: 82/18) 100 parts by weight・ Chromium complex of monoazo dye (negative charge control agent) 0.
5 parts by weight

The above mixture was melt-kneaded with a twin-screw extruder heated to 130 ° C., the cooled kneaded product was coarsely pulverized with a hammer mill, and the coarsely pulverized product was finely pulverized with a jet mill. Was classified with a fixed wall type air classifier to produce classified powder. A fine black powder having a volume average particle diameter of 12.3 μm is obtained by precisely and simultaneously removing fine powder and coarse powder with a multi-division classifier (Elbowjet classifier manufactured by Nittetsu Mining Co., Ltd.) using the Coanda effect. (Magnetic toner particles)
Got The black fine powder obtained had a value of -12 μc / g when the triboelectric charge was measured after mixing with the iron powder carrier.

With respect to 100 parts by weight of the above magnetic toner, the amount of 0.
The magnetic developer (13) according to the present invention was obtained by adding 5 parts by weight of the negatively chargeable silica fine powder and mixing them well.

When the magnetic developer (13) was imaged using a laser beam printer LBP-8 manufactured by Canon, the image density was as high as 1.35 and a clear image with less fog was obtained. According to the description of JIS C 6251-1980, 1,000 sheets of MICR characters were printed. The magnetic property of magnetic printing is obtained by applying magnetism to MICR characters printed by using the commercially available MICR reader / sorter (Model 6780 manufactured by NCR Co., Ltd.) with 1,000 sheets of printed matter, and correctness rate of magnetic reading is obtained. When the (recognition rate) was examined, good results were obtained indicating a recognition rate of 89.5%.

Example 14 A magnetic developer (14) was prepared in the same manner as in Example 13 except that the magnetic material 22 was used in place of the magnetic material 21. When images were printed out in the same manner as in Example 13, the image density was as high as 1.35,
A clear image with less fog was obtained. Further, when MICR characters were printed in the same manner and the correctness rate (recognition rate) of magnetic reading was examined, a good result of 91.4% was obtained.

(Example 15) A magnetic developer (15) was prepared in the same manner as in Example 13 except that the magnetic substance 23 was used in place of the magnetic substance 21. When images were printed out in the same manner as in Example 13, the image density was as high as 1.35,
A clear image with little fog was obtained, and MICR characters were printed in the same manner to examine the accuracy rate (recognition rate) of magnetic reading, and a good result of 93.8% was obtained.

Comparative Example 16 A magnetic developer for comparison (6) was prepared in the same manner as in Example 13 except that the magnetic substance 24 was used in place of the magnetic substance 21. When images were printed out in the same manner as in Example 13, the image density was as low as 1.2, which was clearly inferior. Further, MICR characters were printed and the accuracy rate (recognition rate) of magnetic reading was examined. However, it was clearly inferior at 52.0%.

The results of Examples 13 to 15 and Comparative Example 6 are shown in Table 8.

[0212]

[Table 8]

(Production Example of Magnetic Substances 25-27) Using ferrous sulfate as a raw material, a synthetic reaction of a magnetic substance was carried out by a wet synthesis method in which an oxidation reaction was carried out in an aqueous solution. A magnetic material containing silicon element and aluminum element was obtained by adding sodium silicate and aluminum hydroxide during the synthetic reaction of this magnetic material. 750 using the obtained magnetic material as a raw material
To oxidize the raw material to α-Fe ₂ O ₃ by bubbling air at ℃ for 2 hours, and then bubbling a mixture of hydrogen gas and nitrogen gas for 3 hours at a temperature of 350 ° C. To prepare a magnetic material. The magnetic material was subjected to a crushing treatment for crushing the agglomeration of the magnetic material using a Fred mill to prepare magnetic materials 25 to 27 shown in Table 9.

(Production Example of Magnetic Material 28) Using ferrous sulfate as a raw material, a synthetic reaction of a magnetic material was performed by a wet synthesis method in which an oxidation reaction was performed in an aqueous solution to obtain a magnetic material. The magnetic material was subjected to a crushing treatment for crushing the magnetic material using a Fred mill to prepare a magnetic material 28 shown in Table 9.

[0215]

[Table 9]

(Example 16) 60 parts by weight of magnetic material 25 100% by weight of styrene-butyl acrylate copolymer (weight average molecular weight: 315,000, styrene / butyl acrylate copolymerization ratio: 82/18) Chromium complex of monoazo dye (negative charge control agent 90.
5 parts by weight

The above mixture was melt-kneaded with a twin-screw extruder heated to 130 ° C., the cooled kneaded product was coarsely pulverized with a hammer mill, and the coarsely pulverized product was finely pulverized with a jet mill, and the obtained finely pulverized powder was fixed. The powder was classified by a wall-type wind power classifier. Multi-division classifier using the Coanda effect (Elbowjet classifier manufactured by Nittetsu Mining Co., Ltd.)
Then, the fine powder and the coarse powder were strictly classified and removed at the same time to obtain a black fine powder (magnetic toner particles) having a volume average particle diameter of 12.0 μm. The black fine powder obtained had a value of −9.8 μc / g, as measured by triboelectric charge after mixing with the iron powder carrier.

The magnetic developer (16) according to the present invention was obtained by adding 0.5 parts by weight of negatively chargeable silica fine powder to 100 parts by weight of the above magnetic toner particles and mixing them well.

When the magnetic developer (16) was imaged using a laser beam printer LBP-8 manufactured by Canon, the image density was as high as 1.35 to 1.4, and a clear image with less fog was obtained. Obtained. Also, JIS C 6251
According to the description of -1980, the MICR character printing is 1,
I made 000 sheets. This 1,000 sheets of printed matter are printed on a commercially available M
ICR leader sorter (NCR 6780 type machine)
Magnetic properties were imparted to the MICR characters printed by using, the magnetism of the characters was read, and the accuracy rate (recognition rate) of the magnetic reading was examined. As a result, a good result of 94.1% was obtained.

Example 17 A magnetic developer (17) was prepared in the same manner as in Example 16 except that the magnetic substance 26 was used in place of the magnetic substance 25. When images were printed out in the same manner as in Example 16, a high image density of 1.35 was obtained, and a clear image with less fog was obtained.
When ICR characters were printed and the correctness rate (recognition rate) of magnetic reading was examined, a good result of 89.2% was obtained.

Example 18 A magnetic developer (18) was prepared in the same manner as in Example 16 except that the magnetic substance 27 was used in place of the magnetic substance 25. When images were printed out in the same manner as in Example 16, a high image density of 1.35 was obtained, and a clear image with less fog was obtained.
When ICR characters were printed and the correctness rate (recognition rate) of magnetic reading was examined, a good result of 92.7% was obtained.

(Comparative Example 7) Magnetic material 2 was used in place of magnetic material 25.
A comparative magnetic developer (7) was prepared in the same manner as in Example 16 except that No. 8 was used. When images were printed out in the same manner as in Example 16, the image density was as low as 0.4, which was clearly inferior. Further, MICR characters were printed to check the accuracy rate (recognition rate) of magnetic reading. Where 3
It was clearly inferior at 8.4%.

The triboelectric charge of the magnetic toner particles in Comparative Example 7 after mixing with iron powder was −2.4 μc / g.

The results of Examples 16-18 and Comparative Example 7 are shown in Table 10.

[0225]

[Table 10]

[0226]

The magnetic developer of the present invention has the following effects because it has a magnetic material containing silicon element and aluminum element.

The magnetic developer has a large triboelectric charge amount and a sharp charge amount distribution. Therefore, when the magnetic developer is used in an image forming apparatus, reproducibility of fine lines, gradation and resolution are improved. Excellent images are obtained.

Further, even when the magnetic developer is used 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, fine line reproducibility, gradation and resolution are obtained. An image with excellent properties is obtained. Even when MICR characters are printed, they can be faithfully reproduced according to the standard and an excellent recognition rate can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view of an apparatus for measuring triboelectric charge amounts of a magnetic developer and silica fine powder in triboelectric charge amount measurement.

FIG. 2 is a schematic configuration diagram showing an electrophotographic apparatus of the present invention.

FIG. 3 is a diagram showing “on-as” symbols printed as MICR characters to evaluate thin line reproducibility.

FIG. 4 is a diagram showing a signal waveform of the “on-as” symbol of FIG.

[Explanation of symbols]

701 Electrostatic charge image carrier 702 charging means 703 transfer means 704 Development sleeve 705 Latent image forming means 706 erase exposure 707 Roller fixing device 708 cleaning means 709 developing means 710 Magnetic developer 711 magnetic blade 712 bias applying means

   ─────────────────────────────────────────────────── ─── Continued front page    (31) Priority claim number Japanese Patent Application No. 2-265043 (32) Priority date October 4, 1990 (October 1990) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 2-265037 (32) Priority date October 4, 1990 (October 1990) (33) Priority claiming country Japan (JP)

Claims (40)

(57) [Claims] 1. A magnetic developer having magnetic toner particles having a magnetic material, wherein the magnetic material contains a silicon element and an aluminum element and has a residual magnetization (σr) of 12 to 30 emu / g, and the magnetic permeability (μ) is 2.0 to
A magnetic developer having a ratio of 4.0 and a change coefficient calculated by the following formula of 20% or more. [Outer 1] 2. A magnetic body contains 0.1 to 1.0% by weight elemental silicon in terms of SiO ₂ (magnetic reference), Al ₂
0.1 to 1.0% by weight of aluminum element in terms of O _3.
(1) A magnetic substance is contained as a reference.
The magnetic developer described. 3. The magnetic substance is a silicon element in terms of SiO _2.
0.1-1.0% by weight (magnetic reference) contains, Al ₂
0.1 to 1.0% by weight of aluminum element in terms of O _3.
(Based on magnetic material) Characteristic of containing magnetic iron oxide
The magnetic developer according to claim 1. 4. The magnetic material has a coercive force (Hc ) of 130 to 300 Oersted.
4. The magnetic developer according to any one of 3 to 3. 5. A magnetic body, 5~30ml / linseed oil absorption amount of 100g and characterized by having a packed bulk density of 1.2 to 2.5 g / cm ³ according to claim 1 to 4 Neu
The magnetic developer according to any one of the above. 6. The coefficient of change of the magnetic material is 20 to 50% .
Magnetic developer according to any one of claims 1 to 5, characterized in that. 7. The magnetic material has an average particle size of 0.1 to 0.6 μm.
7. m according to any one of claims 1 to 6, characterized in that
The magnetic developer according to 1. 8. The magnetic material has an average particle size of 0.15 to 0.4.
Any of claims 1 to 6 having a thickness of μm.
The magnetic developer according to claim 1. 9. The magnetic material has a major axis / minor axis ratio of 1.0 to 1.
5. The method according to claim 1, wherein the number is 5.
The magnetic developer described. 10. The major axis / minor axis ratio of the magnetic material is 1.0 to
1.4, any of claims 1 to 8 characterized in that
The magnetic developer according to claim 1. 11. An electrostatic charge image carrier for carrying an electrostatic charge image, a developing means for developing the electrostatic charge image, a charging means for charging the surface of the electrostatic charge image carrier, and / or the charging means. An apparatus that is integrally detachably attached to a main body of the apparatus to form a unit by integrally supporting a cleaning means for contacting the surface of the electrostatic charge image carrier and cleaning the surface of the electrostatic charge image carrier. In the unit, the developing means contains a silicon element and an aluminum element, has a residual magnetization (σr) of 12 to 30 emu / g, a magnetic permeability (μ) of 2.0 to 4.0, and An apparatus unit comprising a magnetic developer having magnetic toner particles having a magnetic substance having a coefficient of change calculated by the following formula of 20% or more. [Outside 2] 12. The magnetic substance contains 0.1 to 1.0% by weight (based on the magnetic substance) of silicon element in terms of SiO _2.
0.1 to 1.0% by weight of aluminum element in terms of ₂ O ₃
Claim 1, characterized in that it (magnetic reference) containing
1. The device unit according to 1 . 13. The magnetic material is SiO ₂ Converted to silicon
0.1 to 1.0% by weight (based on magnetic material)
₂ O ₃ 0.1% to 1.0% by weight of aluminum element
(Based on magnetic material) Characteristic of containing magnetic iron oxide
The device unit according to claim 11. 14. The apparatus unit according to claim 11, wherein the magnetic material has a coercive force (Hc ) of 130 to 300 Oersted. 15. The magnetic substance is 5 to 30 ml / 100 g.
Claims 11 to 1, characterized in that the have a packed bulk density of linseed oil absorption amount and 1.2 to 2.5 g / cm ³
4. The device unit according to any one of 4 above. 16. The magnetic material has a coefficient of change of 20 to 50%.
Any one of claims 11 to 15, characterized in that it is
Apparatus unit according to. 17. The magnetic material has an average particle diameter of 0.1 to 0.6.
17. The method according to claim 11, further comprising:
The device unit described in any way. 18. The magnetic material has an average particle diameter of 0.15 to 0.
The device unit according to claim 11, wherein the device unit has a thickness of 4 μm. 19. The magnetic substance has a major axis / minor axis ratio of 1.0 to
19. The method according to claim 11, wherein the value is 1.5.
The device unit described in any way. 20. The magnetic substance has a major axis / minor axis ratio of 1.0 to
It is 1.4, It is characterized by the above-mentioned.
The device unit described in any way. 21. An electrostatic charge image carrier for carrying an electrostatic charge image, charging means for charging the surface of the electrostatic charge image carrier, and an electrostatic charge image on the surface of the charged electrostatic charge image carrier. A latent image forming means for forming, a developing means for developing the electrostatic charge image formed on the surface of the electrostatic charge image carrier to form a developed image, and a transfer for transferring the developed image to a transfer material. In the electrophotographic apparatus having a means, the developing means contains a silicon element and an aluminum element, has a residual magnetization (σr) of 12 to 30 emu / g, and a magnetic permeability (μ) of 2.0 to 4. An electrophotographic apparatus comprising a magnetic developer having magnetic toner particles having a magnetic substance having a change coefficient of 20% or more, which is 0, and is calculated by the following formula. [Outside 3] 22. The magnetic substance contains 0.1 to 1.0% by weight (based on the magnetic substance) of silicon element in terms of SiO _2.
0.1 to 1.0% by weight of aluminum element in terms of ₂ O ₃
3. A magnetic material is contained (based on a magnetic material).
1. The electrophotographic apparatus according to 1 . 23. The magnetic material is SiO ₂ Converted to silicon
0.1 to 1.0% by weight (based on magnetic material)
₂ O ₃ 0.1% to 1.0% by weight of aluminum element
(Based on magnetic material) Characteristic of containing magnetic iron oxide
22. The electrophotographic apparatus according to claim 21. 24. The electrophotographic apparatus according to claim 21, wherein the magnetic material has a coercive force (Hc ) of 130 to 300 Oersted. 25. The magnetic substance is 5 to 30 ml / 100 g.
Claim, characterized in that the have a packed bulk density of linseed oil absorption amount and 1.2 to 2.5 g / cm ³ 21 to 2
The electrophotographic apparatus according to any one of 4 above. 26. The coefficient of change of the magnetic material is 20 to 50%.
Any of claims 21 to 25, characterized in that it is
The electrophotographic apparatus according to. 27. The magnetic material has an average particle size of 0.1 to 0.6.
27. The method according to any one of claims 21 to 26, characterized in that
The electrophotographic apparatus according to any one of the above. 28. The magnetic material has an average particle diameter of 0.15 to 0.
27. According to claim 21 to 26, characterized in that it has a thickness of 4 μm.
The electrophotographic apparatus according to any one. 29. The magnetic substance has a major axis / minor axis ratio of 1.0 to
29. The method according to claim 21, wherein the value is 1.5.
The electrophotographic apparatus according to any one of the above. 30. The major axis / minor axis ratio is 1.0 to 30.
29. The method according to claim 21, wherein the value is 1.4.
The electrophotographic apparatus according to any one of the above. 31. 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 magnetic ink symbol to which magnetism is imparted. The magnetic developer contains silicon element and aluminum element and has a residual magnetization (σr) of 12 to 30 emu / g.
And magnetic permeability (μ) of 2.0 to 4.0, and a magnetic toner particle having a magnetic material having a coefficient of change of 20% or more calculated by the following formula. To identify magnetic ink symbols. [Outside 4] 32. The magnetic substance contains 0.1 to 1.0% by weight (based on the magnetic substance) of silicon element in terms of SiO _2.
0.1 to 1.0% by weight of aluminum element in terms of ₂ O ₃
Claim 3, characterized in that it is (magnetic reference) containing
1. A method for identifying a magnetic ink symbol according to 1 . 33. The magnetic material is SiO ₂ Converted to silicon
0.1 to 1.0% by weight (based on magnetic material)
₂ O ₃ 0.1% to 1.0% by weight of aluminum element
(Based on magnetic material) Characteristic of containing magnetic iron oxide
32. The magnetic ink symbol identifying method according to claim 31. 34. The magnetic ink symbol identifying method according to claim 31, wherein the magnetic material has a coercive force (Hc ) of 130 to 300 Oersted. 35. The magnetic substance is 5 to 30 ml / 100 g.
Linseed oil absorption of 1.2 to 2.5 g / cm ^{3 and} a compacted apparent density of 1.2 to 2.5 g / cm 3.
4. The magnetic ink symbol identification method according to any one of 4 above. 36. The coefficient of change of the magnetic material is 20 to 50%.
Claim 31 or 35, characterized in that it is
Magnetic ink symbol identification methods described. 37. The magnetic material has an average particle size of 0.1 to 0.6.
37. The method according to any one of claims 31 to 36, characterized in that
The method for identifying a magnetic ink symbol according to any of the above. 38. The magnetic material has an average particle size of 0.15 to 0.
37 μm, having a thickness of 4 μm.
The magnetic ink symbol identification method according to any one of the above. 39. The magnetic material has a major axis / minor axis ratio of 1.0 to
It is 1.5, It is characterized by the above-mentioned 31-38.
The method for identifying a magnetic ink symbol according to any of the above. 40. The major axis / minor axis ratio is 1.0 to 40.
The method according to any one of claims 31 to 38, which is 1.4.
The method for identifying a magnetic ink symbol according to any of the above.