JPH08272136A - Toner and image forming method - Google Patents

Abstract

PURPOSE: To provide a toner which is provided with excellent toner image transfer efficiency and can produce a high quality image even when image formation is carried out continuously under a low temperature and low humidity environment. CONSTITUTION: In a toner consisting of toner grain, in which a binding resin and magnetic iron oxide are contained, and inorganic fine powder, the magnetic iron oxide contains 0.4-4% by mass of silicon elements or/and 0.05-10% by mass of aluminum elements, a toner shape factor SF-1 measured by a toner image analysis device is 110<SF-1<=180, a value of SF-2 is 110<SF-2<=140, a ratio B/A of a value B found by subtracting 100 from the value of SF-2 to a value A found by subtracting 100 from the value of SF-1 is 1.0 or less, a relationship between a toner specific surface area Sb (m<2> /cm<3> ) measured by a BET method and a specific surface area St (m<2> /cm<3> ) found from a weight average grain diameter on the assumption that the toner is a right sphere satisfies such conditions as 0<=Sb/St<=7.0 and Sb<=St×1.5+1.5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner and an image forming method used in a recording method using an electrophotographic method, an electrostatic recording method, a magnetic recording method and the like. For more information,
The present invention, after forming a toner image on the electrostatic latent image carrier in advance,
The present invention relates to a toner used in a copying machine, a printer, a fax, and an image forming method for forming an image by transferring onto a transfer material.

[0002]

2. Description of the Related Art Conventionally, a large number of electrophotographic methods are known, but generally, a photoconductive substance is used and an electric latent image is formed on an image bearing member (photoreceptor) by various means. After forming the latent image, the latent image is developed with toner to form a visible image, and the toner image is transferred to a transfer material such as paper as necessary, and then the toner image is fixed on the transfer material by heat or pressure. To obtain a copy.

As a method for visualizing an electric latent image, a cascade developing method, a magnetic brush developing method, a pressure developing method and the like are known. Further, there is also used a method in which a magnetic toner is used and a rotating sleeve having a magnetic pole at the center is used to fly between the photosensitive member and the sleeve by an electric field.

Unlike the two-component system, the one-component developing system does not require carrier particles such as glass beads and iron powder, so that the developing device itself can be made compact and lightweight. Further, since the two-component developing system needs to keep the toner concentration in the carrier constant, a device for detecting the toner concentration and supplying a required amount of toner is required. Therefore, also in this case, the developing device becomes large and heavy. Such a device is not necessary in the one-component developing system, and it is preferable because it can be made small and light.

In addition, LED and LBP printers have become the mainstream of the market in recent years as the printer apparatus, and the direction of technology is higher resolution, that is, 400, 600, 800 dpi instead of 240, 300 dpi in the past. ing. Therefore, the developing system is also required to have higher definition. Further, the copiers are also becoming more sophisticated, and as a result, they are moving toward digitalization. In this direction, the method of forming an electrostatic charge image by a laser is mainly used, and therefore, it is also advancing toward high resolution, and here also, as in the case of a printer, a high resolution / high definition developing method is required. . For this reason, the particle size of the toner is being reduced, and it is disclosed in Japanese Patent Laid-Open Nos. 1-112253 and 1-1.
No. 91156, No. 2-214156, No. 2-284158, No. 3-181952.
Japanese Patent Application Laid-Open No. 4-162048 and Japanese Patent Application Laid-Open No. 4-162048 propose a toner having a specific particle size distribution and a small particle size.

The toner image formed on the photoconductor in the developing process is transferred to the transfer material in the transfer process, but the transfer residual toner remaining on the photoconductor is cleaned in the cleaning process.
Toner is stored in the waste toner container. For this cleaning process, blade cleaning, fur brush cleaning, roller cleaning, etc. have been conventionally used. From the viewpoint of the apparatus, the size of the apparatus is inevitably increased due to the provision of such a cleaning apparatus, which has been a bottleneck when aiming to make the apparatus compact. Further, from the viewpoint of ecology, a system with less waste toner is desired in terms of effective utilization of toner, and a toner with good transfer efficiency has been demanded.

Regarding the improvement of transfer efficiency, Japanese Patent Publication No. 56-
A method of atomizing a molten mixture into air using a disk or a multi-fluid nozzle described in Japanese Patent No. 13945 and the like, and Japanese Patent Publication No. 36-10231 and Japanese Patent Laid-Open No. 59-5.
No. 3,856, Japanese Patent Laid-Open No. 59-61842, a spherical toner by a method of directly producing a toner using the suspension polymerization method, a non-spherical polymer toner by hetero-aggregation of emulsion polymer particles, etc. However, the durability and the development stability in long-term repeated use are still insufficient.

Japanese Patent Application Laid-Open No. 61-279864 proposes a toner which defines shape factors SF-1 and SF-2. However, there is no description regarding transfer in this publication, and as a result of carrying out Examples, transfer efficiency is low and further improvement is required.

Further, Japanese Patent Application Laid-Open No. 63-235953 proposes a magnetic toner spherically shaped by a mechanical impact force. However, the transfer efficiency is still insufficient and further improvement is needed. As described above, it has been attempted to make the conventional pulverized toner spherical by mechanical impact force or heat, but there is still a problem in the development stability in long-term repeated use.

Further, in recent years, from the viewpoint of environmental protection, the primary charging and transfer processes using corona discharge, which have been conventionally used, are becoming mainstream, and the primary charging and transfer processes using a photoconductor contact member are becoming mainstream.

For example, JP-A-63-149669 and JP-A-2-123385 have been proposed. These are related to the contact charging method and the contact transfer method, but a conductive elastic roller is brought into contact with the electrostatic latent image carrier,
While electrostatically charging the electrostatic latent image carrier while applying a voltage to the conductive roller, another voltage was applied to the electrostatic latent image carrier after obtaining a toner image by exposure and development steps. While transferring the transfer material while pressing the conductive roller to transfer the toner image on the electrostatic latent image bearing member onto the transfer material, a transfer image is obtained through a fixing step.

However, in such a roller transfer system which does not use corona discharge, since the transfer member is brought into contact with the photoconductor through the transfer member during transfer, the toner image formed on the photoconductor is transferred to the transfer material. When the toner image is transferred to the toner image, the toner image is pressed into contact with the toner image, which causes a problem of partial transfer failure, which is so-called transfer void (see FIG. 5).

Further, as the diameter of the toner becomes smaller, the adhesion force of the toner particles (image force, van der Waals force, etc.) to the photoconductor becomes larger than the Coulomb force applied to the toner particles by the transfer. As a result, the transfer residual toner tends to increase.

Further, in the roller charging method, the physical and chemical action of the surface of the electrostatic latent image bearing member due to the discharge generated between the charging roller and the electrostatic latent image bearing member is larger than that in the corona charging method. In particular, in the combination with the organic photoconductor / blade cleaning, abrasion due to deterioration of the photoconductor surface is likely to occur, and there is a problem in life (direct charging /
The combination of the organic photoreceptor / one-component magnetic developing method / contact transfer / blade cleaning makes it easy to reduce the cost and size and weight of the image forming apparatus. This is the mainstream method for printers, facsimiles, etc. ).

Therefore, it has been required that the toner and the photoconductor used in such an image forming method have excellent releasability.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toner and an image forming method which solve the above problems of the prior art.

That is, the object of the present invention is to provide excellent transferability,
An object of the present invention is to provide a toner and an image forming method in which the amount of residual toner after transfer is small and voids in transfer do not occur even in a roller transfer system, or these phenomena are suppressed.

A further object of the present invention is to provide a toner and an image forming method which are both stable in developability with high image density and less fog and excellent transfer efficiency even after printing for a long period of time and after printing a large number of sheets. .

Further, the object of the present invention is to provide a toner and an image forming material which are excellent in releasability and slidability, and which have a long life and a small photoconductor scraping ability even after a long period of time and after printing a large number of sheets. To provide a method.

A further object of the present invention is to provide a toner and an image forming method in which abnormal charging or image defects due to contamination of a member which is pressed against the electrostatic latent image carrier does not occur, or these phenomena are suppressed. It is in.

Further, an object of the present invention is to provide a toner and an image forming method in which a thin layer coat of the toner on the toner carrier is stable and an excellent image is obtained due to the excellent charge controllability even in a low temperature and low humidity environment. To provide.

[0022]

The present invention relates to a toner having toner particles containing at least a binder resin and magnetic iron oxide and inorganic fine powder, wherein the magnetic iron oxide is
(A) 0.4 to 4 mass% of silicon element based on iron element
Alternatively, (b) the aluminum element is 0.05 to 0.05 based on the iron element.
10% by mass, or both the silicon element and the aluminum element in the above proportions, and the shape factor SF-1 of the toner measured by an image analyzer is 110 <SF-1.
≦ 180, and the value of the shape factor SF-2 is 110 <SF.
−2 ≦ 140, and the ratio B / of the value B obtained by subtracting 100 from the value of SF-2 and the value A obtained by subtracting 100 from the value of SF-1
The value of A is 1.0 or less, and the specific surface area Sb (m ² / c) of the toner per unit volume measured by the BET method.
m ³ ), and the specific surface area St (m ² / c) per unit volume calculated from the weight average particle diameter when the toner is assumed to be a true sphere.
m ³ ) satisfies the following condition 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5, and the toner on the electrostatic latent image carrier is An image using an electrophotographic apparatus having a developing step of forming a toner image using toner and a transfer step of transferring the toner image onto the transfer material while bringing a transfer member to which a voltage is applied into contact with the transfer material. It relates to a forming method.

In the present invention, a toner having an SF-1 value of 120≤SF-1≤160 and an SF-2 value of 115≤SF-2≤140 is preferably used.

In the present invention, SF-indicating the shape factor
1 and SF-2 are, for example, Hitachi FE-SEM
(S-800) is used to randomly sample 100 toner images of 2 μm or more magnified 1000 times, and the image information is introduced into an image analysis device (Luzex III) manufactured by Nicolet Co., Ltd. through an interface. The value obtained by performing the analysis and calculating from the following equation is used as the shape factor SF-1, S
It is defined as F-2.

[0025]

[Equation 1]

(Where MXLNG is the absolute maximum length of the particle,
PERIME represents the perimeter of the particle, and AREA represents the projected area of the particle. )

The shape factor SF-1 indicates the degree of roundness of toner particles, and the shape factor SF-2 indicates the degree of unevenness of toner particles.

When the toner shape factor SF-1 is 110 or less, or the toner spherical factor SF-2 is 110 or less, and the ratio B / A is more than 1.0, cleaning failure generally occurs. It is easy to do, and the toner shape factor S
When F-1 exceeds 180, the toner is separated from the sphere and approaches an irregular shape, the toner is easily crushed in the developing device, the particle size distribution is fluctuated, the charge amount distribution is apt to be broad, and background fog and reverse fog occur. Cheap. On the other hand, if SF-2 exceeds 140, the transfer efficiency of the toner image at the time of transfer from the electrostatic image carrier to the transfer material is deteriorated, and character or line image dropout occurs, which is not preferable. At this time, the toner manufactured by the pulverization method is preferably used.

The value of the ratio B / A shows the slope of a straight line passing through the origin in FIG. 6, and this value is preferably 0.2 to
0.9 (further 0.35 to 0.85),
It is preferable because the transferability is improved while maintaining the developability.

Further, by having the inorganic fine powder on the surface of the toner particles, the transfer efficiency is improved and the voids in the transfer of characters and line images are improved. At this time, the specific surface area Sb per unit volume measured by the BET method and the specific surface area St per unit volume (St = 6 / calculated from the weight average particle diameter (D ₄ ) assuming that the toner is a true sphere. D ₄ ) is 3.0 ≦ Sb / St ≦ 7.0 and Sb ≧ St ×
It is preferably 1.5 + 1.5, and further, Sb is 3.2 to 6.8 m ² / cm ³ (more preferably 3.4 to
It is preferably 6.3 m ² / cm ³ ).

If the ratio is less than 3.0 times, the transfer efficiency is insufficient, and if it exceeds 7.0 times, the image density decreases. It is considered that this is because the inorganic fine particles added to the toner particles behave effectively as a spacer between the toner particles and the toner image carrier.

The specific surface area of the toner within the above range can be achieved by controlling the specific surface area of the toner particles, the specific surface area of the inorganic fine powder added to the toner particles, the addition amount and the addition mixing strength. If the addition and mixing strength is too high, the inorganic fine particles will be embedded in the toner particles and the transfer efficiency will not be improved sufficiently.

Further, since the inorganic fine powder is effectively used, the specific surface area Sr per volume of the toner particles is 1.2 to.
2.5m ² / cm ³ (preferably 1.4~2.1m ² / c
m ³ ), which is 1.5 to the theoretical specific surface area per volume calculated from the weight average particle diameter assuming that the toner is a true sphere.
It is good to be 2.5 times.

The specific surface area is preferably increased by 1.5 m ² / cm ³ or more by adding the inorganic fine powder. 1 nm to 100 nm of toner particles before adding inorganic particles
It is preferable that the 60% pore radius calculated from the cumulative pore area ratio curve of the pores is 3.5 nm or less. At this time, the BET specific surface area Sb of the toner and the BET specific surface area S of the toner particles are
The value of the ratio Sb / Sr of r is preferably in the range of 2-5.

These are those in which the inorganic fine powder behaves more effectively and the transfer efficiency is improved by reducing the pores in the toner particles which are larger than the primary particle diameter of the inorganic fine powder added to the toner particles. it is conceivable that.

The specific surface area was determined according to the BET method by using a specific surface area measuring apparatus Autosorb 1 (manufactured by Yuasa Ionics Co., Ltd.) to adsorb nitrogen gas on the sample surface and calculating the specific surface area using the BET multipoint method. Further, the 60% pore radius was calculated from the integrated pore area ratio curve with respect to the desorption side pore radius. In Autosorb 1, the pore size distribution is calculated by Bar
rett, Joyner & Harenda (B.
J. H.). J. The H method is used.

However, when a toner having a shape having the above characteristics is subjected to an image output test under a low temperature and low humidity environment,
It has been found that the continuous image formation tends to disturb the uniformity of the thin layer coat of the toner on the toner carrier, and image defects such as blurring / wavy unevenness are likely to appear on the solid image.

The present inventors have found that the destabilization of the toner thin layer coat occurs because the charge amount per surface area of the toner tends to be higher than that of the conventional toner due to the shape of the toner. I found it. The cause is not necessarily clear, but since there are few irregularities on the toner surface, triboelectric charging with the charging member is carried out at more sites on the toner surface, and the charging opportunity is substantially increased. In order to control the toner to have a predetermined shape and physical properties by using heat and / or mechanical impact force, the magnetic substance existing in the vicinity of the toner surface has a low charge control ability due to the coating of a low molecular weight component of resin, We believe that deterioration of the body surface due to thermal / mechanical stress and deterioration of the charge control capability due to polishing of the surface of the magnetic body have occurred.

Therefore, by using a magnetic material containing a predetermined amount of silicon element and / or aluminum element as the magnetic material, the thermal stability of the magnetic material is enhanced and excess charging of the toner is leaked more efficiently. Then, it was found that the charge controllability of the toner can be improved more than ever.

Although the mechanism is not always clear, 1) the dispersibility of the magnetic substance in the toner is improved, and the magnetic substance as a leak site functions more efficiently on the toner surface, and 2) the magnetic substance. It is considered that the presence of the silicon element and / or the aluminum element on the surface improves the charge controllability of the magnetic material on the toner surface.

When the magnetic toner is obtained through mechanical or thermomechanical treatment, it is considered that the magnetic substance near the toner surface has a decrease in charge controllability due to surface polishing or the like. The presence of the silicon element and / or the aluminum element in the magnetic material and the presence of the silicon element and / or the aluminum element in the magnetic material mean that the charge control ability of the magnetic material on the toner surface is improved. More preferable.

In the present invention, the magnetic iron oxide contains (a) a silicon element in an amount of 0.4 to 4% by mass based on the iron element, and / or (b) an aluminum element in an amount of 0.05 to 0.05% based on the iron element. By containing 10% by mass, the outermost surface or composition / structure of magnetic iron oxide can be controlled, and in a toner containing magnetic iron oxide, magnetic substance dispersibility in the toner / charge controllability in a low humidity environment Excellent image is obtained with a stable toner coat even after a long-term durability test and continuous use. If the magnetic iron oxide contains less than 0.4 mass% of silicon element based on the iron element and less than 0.05 mass% of aluminum element based on the iron element, a toner image analyzer The value of the shape factor SF-1 measured in step 110 is 110 <SF-1 ≦ 1.
80 and the value of SF-2 is 110 <SF-2 ≦ 1.
40, which prevents the magnetic iron oxide from falling off from the toner due to mechanical impact when the toner is manufactured or processed so that B / A becomes 1.0 or less, and the toner having such a shape is charged. The effect of the present invention for stabilizing the characteristics cannot be obtained. When the magnetic iron oxide contains more than 4% by mass of the silicon element based on the iron element, the magnetic properties of the magnetic iron oxide are deteriorated or the surface of the magnetic iron oxide is vulnerable to mechanical shock. Even when the magnetic iron oxide contains aluminum element in an amount of more than 10% by mass based on the iron element, the magnetic properties of the magnetic iron oxide are deteriorated or the charge stability of the toner, particularly the chargeability under high humidity is impaired. .

The Fe / Si atomic ratio on the outermost surface of the magnetic iron oxide is preferably 1.2 to 4.0. Further, the Fe / Al atomic ratio on the outermost surface of the magnetic iron oxide is 0.3 to
It is preferably 10.0. When the Fe / Si atomic ratio on the outermost surface of the magnetic iron oxide is larger than 4.0, the surface of the magnetic iron oxide is vulnerable to mechanical shock, and the chargeability of the toner is changed by repeated use for a long time. The effect of the present invention is obtained when the Fe / Si atomic ratio on the outermost surface of the magnetic iron oxide is smaller than 1.2 or when the Fe / Al atomic ratio on the outermost surface of the magnetic iron oxide is smaller than 0.3. Absent. When the Fe / Al atomic ratio on the outermost surface of the magnetic iron oxide is larger than 10.0, there arises a disadvantage that the change of the charging property due to the environment of the toner becomes large.

Further, the dissolution rate of iron element of magnetic iron oxide is 20.
The ratio (b / a) × 100 of the content ratio b of the silicon element existing up to the mass% and the total content a of the silicon element of the magnetic iron oxide is 100.
It is 4 to 84%, and the ratio of the content c of the silicon element existing on the surface of the magnetic iron oxide to the total content a of the silicon element (c /
It is preferable that a) × 100 is 10 to 55%. The content b of the silicon element present in the iron oxide dissolved in the magnetic iron oxide up to 20% by mass and the total content a of the silicon element of the magnetic iron oxide a
When the ratio (b / a) × 100 is less than 44% and a large amount of silicon element is present in the central part of the magnetic iron oxide, it is difficult to control the magnetic properties and the production efficiency of the magnetic iron oxide is likely to decrease. Become. The ratio (b / a) × 100 of the content b of the silicon element present in the magnetic iron oxide having an iron element dissolution rate of up to 20% by mass and the total content a of the silicon oxide of the magnetic iron oxide (b / a) × 100 is more than 84%. If it becomes large, the surface of the magnetic iron oxide is vulnerable to mechanical shock, and the chargeability of the toner may change after repeated use for a long time. The ratio of the content c of the silicon element existing on the surface of the magnetic iron oxide to the total content a of the silicon element (c
If / a) × 100 is smaller than 10%, the effect of the present invention cannot be obtained. Ratio (c / a) of the content c of the silicon element existing on the surface of the magnetic iron oxide and the total content of the silicon element
When x100 is larger than 55%, irregularities are conspicuous on the surface of the magnetic iron oxide, and the irregularities become fragments during the toner production, which reduces the dispersibility of the magnetic iron oxide in the toner and the charging of the toner. Reduce sex.

In the present invention, the content of silicon element on the surface of magnetic iron oxide can be determined by the following method.
For example, about 3 liters of deionized water is put into a 5 liter beaker, and heated in a water bath so that the temperature becomes 50 to 60 ° C. About 25 g of magnetic iron oxide slurried in about 400 ml of deionized water is added to a 5 liter beaker with the deionized water while washing with about 30 ml of deionized water. Then, while maintaining the temperature at about 60 ° C. and the stirring speed at about 200 rpm, sodium hydroxide such as silicic acid on the surface of the magnetic iron oxide particles is started to be dissolved by adding special grade sodium hydroxide to obtain about 1N sodium hydroxide solution. .
20 ml was sampled 30 minutes after the start of dissolution,
Filter through a 1 μm membrane filter and collect the filtrate. The filtrate is quantified for silicon element by plasma emission spectrometry (ICP). The content of silicon element corresponds to the silicon element concentration (mg / liter) per unit mass of magnetic iron oxide in the sodium hydroxide solution.

In the present invention, the content rate of silicon element (based on iron element), the dissolution rate of iron element and the content of silicon element in the dissolution rate can be determined by the following method. For example, about 3 liters of deionized water is placed in a 5 liter beaker and heated in a water bath to 45 to 50 ° C. About 25 g of magnetic iron oxide slurried in about 400 ml of deionized water is added to a 5 liter beaker with the deionized water while washing with about 30 ml of deionized water. Then, while maintaining the temperature at about 50 ° C. and the stirring speed at about 200 rpm, special grade hydrochloric acid is added to start the dissolution. At this time, the magnetic iron oxide concentration is about 5 g / liter and the hydrochloric acid aqueous solution is about 3 N. 20 ml is sampled several times from the start of dissolution to the time when everything is dissolved and the solution becomes transparent, filtered through a 0.1 μm membrane filter, and the filtrate is collected. The filtrate is analyzed by plasma emission analysis (IC
According to P), the iron and silicon elements are quantified. The iron element dissolution rate for each sample is calculated by the following formula.

[0047]

[Equation 2]

The content and content of the silicon element for each sample are calculated by the following equation.

[0049]

(Equation 3)

The total content of silicon elements in the magnetic iron oxide corresponds to the silicon element concentration (mg / liter) per unit mass of the magnetic iron oxide after all are dissolved.

The content of the elemental silicon in the magnetic iron oxide corresponds to the concentration (mg / liter) of the elemental silicon per unit mass of the magnetic iron oxide detected when the dissolution rate of the magnetic iron oxide is 20%.

The total content of silicon elements in the magnetic iron oxide, the content of silicon elements present in the magnetic iron oxide with a dissolution rate of iron elements of up to 20% by mass, and the content of silicon elements present on the surface of the magnetic iron oxide were determined. As a measuring method, (1) a sample of magnetic iron oxide is divided into two, and the total content of silicon elements and the content of silicon elements whose iron element dissolution rate is up to 20% by mass are measured. , A method of separately measuring the content of the silicon element existing on the surface, and (2) measuring the content of the silicon element existing on the surface, using the sample after the measurement, and then the iron element dissolution rate is 20 mass. % Of the amount of silicon elements present on the surface minus the amount of silicon elements present on the surface and the total content minus the amount of silicon elements present on the surface. Content and iron element dissolution rate of 20% by mass
Examples thereof include a method of calculating the content of silicon elements existing up to now.

Further, the Fe / Si atomic ratio and the Fe / Al atomic ratio on the outermost surface of the magnetic iron oxide in the present invention can be obtained by XPS measurement. In the present invention, an X-ray photoelectron spectrometer ESC is used as the XPS measuring device.
A LAB, 200-X type (manufactured by VG) was used, the measurement was carried out with an X-ray source of MgKα (300 W) and an analysis area of 2 × 3 mm.

In order to faithfully develop finer latent image dots for higher image quality, the toner particles have a weight average diameter of 4
The thickness is preferably 9 to 9 μm. Weight average diameter is 4μ
With toner particles of less than m, a large amount of toner remains after being transferred on the photoconductor due to a decrease in transfer efficiency, and moreover, it is likely to cause uneven image unevenness due to fog and transfer failure. Not preferable. Further, when the weight average diameter of the toner particles exceeds 9 μm, scattering of characters and line images is likely to occur.

For the average particle size and particle size distribution of the toner, a Coulter Counter TA-II type or a Coulter Multisizer (manufactured by Coulter Co.) is used, and an interface (manufactured by Nikkaki Co., Ltd.) for outputting number distribution and volume distribution and PC9.
801 personal computer (manufactured by NEC) is connected, and the electrolyte is 1% NaCl using primary sodium chloride.
Prepare an aqueous solution. For example, ISOTON R-II
(Manufactured by Coulter Scientific Japan) can be used. As the measuring method, the electrolytic aqueous solution 100 to 1 is used.
0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) as a dispersant is added to 50 ml,
Further, 2 to 20 mg of the measurement sample is added. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the volume and number of toner particles having a size of 2 μm or more were measured using a 100 μm aperture as an aperture with the Coulter Counter TA-II type. The volume distribution and number distribution were calculated. Then, the volume-based weight average particle diameter (D ₄ ) obtained from the volume distribution and the number-based length average particle diameter (D ₁ ) obtained from the number distribution according to the present invention were obtained.

The charge amount per unit volume (two-component method) of the toner according to the present invention is 30 to 80 C / m ³ (more preferably 40 to 70 C / m ³ ). It is preferable for improving transfer efficiency in a transfer method using a member.

The method for measuring the charge amount (two-component tribo) of the toner according to the present invention by the two-component method is shown below (FIG. 4).

In an environment of 23 ° C. and relative humidity of 60%, EFV200 / 300 (manufactured by Powder Tech Co., Ltd.) was used as a carrier, and a mixture of 9.5 g of carrier and 0.5 g of toner was added to a polyethylene bottle having a capacity of 50 to 100 ml. Shake by hand 50 times. Next, 1.0 to 1.2 g of the mixture is put into a metal measuring container 22 having a 500-mesh screen 23 on the bottom, and a metal lid 24 is placed. At this time, the total mass of the measurement container 22 is weighed and set as W ₁ (g). Next, in the suction device (at least the portion in contact with the measurement container 22 is an insulator), suction is performed from the suction port 27 and the air flow rate control valve 26 is adjusted to adjust the pressure of the vacuum gauge 25 to 2450 Pa (25
0 mmAq). In this state, suction is performed for 1 minute to remove the toner by suction. The potential of the electrometer 29 at this time is V
(Volts). Here, 28 is a capacitor, and the capacitance is C (μF). Further, the mass of the entire measuring machine after suction is weighed and designated as W ₂ (g). Triboelectric charge amount of this toner (m
C / kg) is calculated by the following formula.

Triboelectric charge amount (mC / kg) = CV / (W ₁ −W ₂ ).

The binder resin used in the toner according to the present invention has a low molecular weight peak in the range of 3000 to 15000 in the GPC molecular weight distribution. It is preferable for controlling with impact force. Low molecular weight peak is 1
When it exceeds 5,000, it is difficult to control the shape factors SF-1 and SF-2 within the range of the present invention, and the transfer efficiency is not sufficiently improved. On the other hand, if it is less than 3000, fusion tends to occur during surface treatment. The molecular weight is measured by GPC (gel permeation chromatography). Specific GPC
As a measuring method, a sample obtained by previously extracting the toner with a Soxhlet extractor for 20 hours with a THF (tetrahydrofuran) solvent was used, and the column configuration was Showa Denko A
-801, 802, 803, 804, 805, 806
The molecular weight distribution can be measured by connecting 807 and using a calibration curve of a standard polystyrene resin.

A resin having a weight average molecular weight (Mw) to number average molecular weight (Mn) ratio (Mw / Mn) of 2 to 100 is preferable for the present invention.

The glass transition point Tg of the toner is preferably 50 ° C. to 75 ° C. (more preferably 52 ° C. to 70 ° C.) from the viewpoints of fixability and storability.

Glass transition point Tg of the toner according to the present invention
For example, DSC- manufactured by Perkin Elmer Co., Ltd.
The measurement is performed with a highly accurate internal heat input compensation type differential scanning calorimeter such as 7. The measuring method is ASTM D3418-8.
Perform according to 2. In the present invention, the sample is heated once to take a previous history, then rapidly cooled, and then again at a temperature rate of 10 ° C./m.
In, a DSC curve measured when the temperature is raised in the range of 0 to 200 ° C. is used.

The type of the binder resin used in the present invention is, for example, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, or a substitution product thereof; styrene-p-chlorostyrene copolymerization. Coal, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene- Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile- Styrene-based copolymers such as indene copolymers Combined; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin , Polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. A crosslinked styrene resin is also a preferable binder resin.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate,
Didecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a heavy bond or a substituted product thereof;
For example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate, and the like; and substituted compounds thereof; for example, vinyl chloride,
Vinyl esters such as vinyl acetate, vinyl benzoate, etc., ethylene-based olefins such as ethylene, propylene, butylene, etc .; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, etc .;
For example, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether and the like; and vinyl monomers such as are used alone or in combination. Here, as the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, and examples thereof include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate and ethylene glycol. Dimethacrylate,
A carboxylic acid ester having two double bonds such as 1,3-butanediol dimethacrylate; a divinyl compound such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone; and a compound having three or more vinyl groups; Can be used alone or as a mixture.

As the binder resin for toner used for pressure fixing, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide Resin and polyester resin may be used. These are preferably used alone or in combination.

Further, it is also preferable to include the following waxes in the toner from the viewpoint of improving the releasability from the fixing member during fixing and the fixing property. Paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, carnauba wax and its derivatives, etc., where the derivatives are oxides and block copolymers with vinyl monomers. , Including graft modified products.

In addition, alcohols, fatty acids, acid amides,
Esters, ketones, hydrogenated castor oil and its derivatives, plant wax, animal wax, mineral wax, petrolactam and the like can also be used.

In the magnetic toner of the present invention, a charge control agent is blended with toner particles (internal addition) or mixed with toner particles (external addition).
It is preferable to use. The charge control agent makes it possible to control the optimum charge amount according to the developing system, and particularly in the present invention, the balance between the particle size distribution and the charge amount can be further stabilized. The following substances control the toner to be negatively charged.

Organic metal complexes and chelate compounds are effective, for example, monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

Further, there are the following substances for controlling the positive charge.

Modified products of nigrosine and fatty acid metal salts and the like; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and phosphonium salts which are analogs thereof. Onium salts and lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as a laker, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide) Compounds, ferrocyanides, etc.), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyl Diorgano tin borate such as Suzuboreto; can be used in combination singly or two or more kinds.

The charge control agents described above are preferably used in the form of fine particles, and in this case, the number average particle diameter of these charge control agents is preferably 4 μm or less, more preferably 3 μm or less. When these charge control agents are internally added to the toner, it is preferable to use 0.1 to 20 parts by mass, particularly 0.2 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

As the colorant used in the present invention, carbon black, a magnetic material, or a yellow / magenta / cyan colorant shown below, which is toned black, is used.

As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 97, 109, 1
10, 111, 120, 127, 128, 129, 14
7, 168, 174, 176, 180, 181, 191
Etc. are preferably used.

As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8; 2, 48; 3, 48; 4, 57; 1, 81; 1, 1
44, 146, 166, 169, 177, 184, 18
5,202,206,220,221,254 are particularly preferred.

As the cyan colorant, a copper phthalocyanine compound and its derivative, an anthraquinone compound, a basic dye lake compound and the like can be used. Specifically, C.I. I.
Pigment Blue 1, 7, 15, 15: 1, 15: 2,
15: 3, 15: 4, 60, 62, 66 and the like can be used particularly preferably.

These colorants can be used alone or in the form of a mixture, or in the form of a solid solution. The colorant of the present invention is selected in terms of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in the toner. The amount of the colorant added is 1 to 20 parts by mass based on 100 parts by mass of the resin.

The magnetic iron oxide of the toner of the present invention is made of resin 10
It is used by adding 30 to 200 parts by mass to 0 part by mass.

The magnetic substance includes metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. In the present invention, iron trioxide, γ-iron oxide, etc. , Magnetic iron oxide containing iron oxide as a main component is preferable, and contains (a) a silicon element in an amount of 0.4 to 4 mass% based on the iron element, and / or (b) an aluminum element based on the iron element. .05-10
It is necessary to contain it by mass%.

A magnetic iron oxide according to the present invention containing 0.4 to 4 mass% of silicon element based on iron element, and / or containing 0.05 to 10 mass% of aluminum element based on iron element was prepared. A known method is used for this purpose. For example, when the ferrous salt aqueous solution is oxidized at 60 to 90 ° C. to generate magnetic iron oxide, the silicon compound aqueous solution and / or
Alternatively, there is a method in which an aqueous solution of an aluminum compound is mixed in the reaction solution before the oxidation reaction to carry out the oxidation reaction, dropped during the oxidation reaction, or added after the completion of the oxidation reaction of the magnetic iron oxide to further react.

The distribution of the silicon element / aluminum element present in the magnetic iron oxide is continuous from the inside to the surface of the magnetic iron oxide particles by the method described in, for example, Japanese Patent Application Laid-Open No. 5-213620. Alternatively, it is preferable to gradually increase.

These magnetic iron oxides can be used as B by the nitrogen adsorption method.
ET specific surface area is preferably 3 to 35 m ² / g, especially 5 to
A magnetic powder having a hardness of 30 m ² / g and a Mohs hardness of 5 to 7 is preferable.

The shape of the magnetic material is octahedron, hexahedron,
There are spheres, needles, scales, etc., but those having little anisotropy such as octahedrons, hexahedrons, spheres, and irregular shapes are preferable for increasing the image density. The average particle size of the magnetic substance is 0.05 to
1.0 μm is preferable, and 0.1 to 0.
6 μm, and more preferably 0.1 to 0.4 μm.

The amount of magnetic material is 3 with respect to 100 parts by mass of the binder resin.
0 to 200 parts by mass, preferably 40 to 200 parts by mass, and more preferably 50 to 150 parts by mass. If the amount is less than 30 parts by mass, in a developing device that uses magnetic force for toner transportation, the transportability is insufficient, and unevenness in the developer layer on the developer carrier tends to result in image unevenness. The image density tends to decrease due to the above. On the other hand, if the amount exceeds 200 parts by mass, the fixing property tends to have a problem.

Known inorganic fine powders may be used as the inorganic fine powder contained in the toner of the present invention. To improve the charging stability, developability, fluidity and storage stability, silica, alumina,
It is preferably selected from titania and its complex oxides. Furthermore, silica is more preferable. For example, as the silica, both a so-called dry method produced by vapor phase oxidation of a silicon halide or an alkoxide or a dry silica called fumed silica and a so-called wet silica produced from alkoxide, water glass, etc. can be used. However, dry silica having less silanol groups on the surface and inside the fine silica powder and less production residues such as Na ₂ O and SO ₃ ²⁻ is preferable. Further, in the case of dry silica, it is also possible to obtain a composite fine powder of silica and other metal oxide by using other metal halogen compound such as aluminum chloride and titanium chloride together with the silicon halogen compound in the manufacturing process. Also includes.

[0087] Inorganic fine powder used in the present invention is the specific surface area by nitrogen adsorption measured by BET method is 30 m ² / g or more, particularly given good results in the range of 50 to 400 m ² / g, the toner 100 mass It is particularly preferable to use 0.1 to 8 parts by mass of fine silica powder, preferably 0.5 to 5 parts by mass, more preferably more than 1.0 and up to 3.0 parts by mass per part.

The inorganic fine powder used in the present invention is
The primary particle size is preferably 30 nm or less.

The inorganic fine powder used in the present invention is
Silicone varnishes, various modified silicone varnishes, silicone oils, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, other organic silicon compounds, organics for the purpose of hydrophobicizing, controlling chargeability, etc. It is also possible and preferable to treat with a treating agent such as a titanium compound or in combination with various treating agents.

In order to maintain a high charge amount and to achieve a low consumption amount and a high transfer rate, it is more preferable that the inorganic fine powder is treated with at least silicone oil.

In the present invention, the transferability and / or
Alternatively, in order to improve the cleaning property, in addition to the inorganic fine powder, the primary particle diameter is more than 30 nm (preferably the specific surface area is less than 50 m ² / g), more preferably 5
0 nm or more (preferably specific surface area less than 30 m ² / g)
It is also one of the preferable modes to further add the inorganic or organic spherical particles. For example, spherical silica particles, spherical polymethylsilsesquioxane particles, spherical resin particles and the like are preferably used.

In the toner of the present invention, other additives are added within a range that does not have a substantial adverse effect, for example, lubricant powders such as Teflon powder, zinc stearate powder, polyvinylidene fluoride powder; cerium oxide powder, silicon carbide. Powder,
Abrasives such as strontium titanate powder; fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder; anti-caking agent, or conductivity-imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder; It is also possible to use a small amount of reverse polarity organic fine particles and inorganic fine particles as a developing property improver.

A known method is used for producing the toner according to the present invention. For example, a binder resin, a wax,
Metal salts or metal complexes, pigments as colorants, dyes,
Alternatively, a magnetic material, if necessary, a charge control agent, other additives and the like are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then melt-kneaded by using a heat kneader such as a heating roll, a kneader or an extruder. The metal compound, the pigment, the dye, and the magnetic substance are dispersed or dissolved in the resin to make them compatible with each other, and after solidification by cooling, pulverization and classification are performed to obtain the toner according to the present invention. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.

Examples of the surface treatment include a hot water bath method in which pulverized toner particles are dispersed and heated in water, a heat treatment method in which a hot air stream is passed, and a mechanical impact method in which mechanical energy is applied for treatment. In the present invention, the processing temperature in the mechanical impact method is set to the glass transition point Tg of the toner particles.
The thermo-mechanical shock that adds a temperature near (Tg ± 10 ℃)
It is preferable from the viewpoint of aggregation prevention and productivity. More preferably, it is carried out at a temperature in the range of the glass transition point Tg ± 5 ° C. of the toner, in order to reduce the pores having a radius of 10 nm or more on the surface, to effectively work the inorganic fine powder, and to improve the transfer efficiency. It is valid.

The present invention is also effective when the surface of the image bearing member is mainly composed of a polymer binder. For example, when a protective film mainly composed of a resin is provided on an inorganic image bearing member such as selenium or amorphous silicon, or as a charge transporting layer of a function separation type organic image bearing member, a surface layer comprising a charge transporting material and a resin. In some cases, the above-mentioned protective layer may be further provided on it. As means for imparting releasability to such a surface layer, a resin having a low surface energy is used as the resin forming the film, water repellency,
Examples thereof include adding an additive that imparts lipophilicity, dispersing a material having a high mold release property into a powder, and dispersing the powder. For example, it is achieved by introducing a fluorine-containing group, a silicon-containing group or the like into the resin structure. For this, a surfactant or the like may be used as an additive. Examples thereof include compounds containing a fluorine atom, that is, powders of polytetrafluoroethylene, polyvinylidene fluoride, carbon fluoride and the like. Among these, polytetrafluoroethylene is particularly preferable. In the present invention, it is particularly preferable to disperse the releasable powder such as the fluorine-containing resin in the outermost surface layer.

By these means, the contact angle of water on the surface of the image bearing member can be 85 degrees or more (preferably 90 degrees or more). If it is less than 85 degrees, deterioration of the toner and the toner carrier due to durability tends to occur.

In order to contain these powders on the surface, a layer in which the powders are dispersed in a binder resin is provided on the outermost surface of the image bearing member, or an organic material mainly composed of a resin is used. In the case of an image carrier, the powder may be dispersed in the uppermost layer without providing a new surface layer.

The amount of the powder added to the surface layer is preferably 1 to 60% by mass, more preferably 2 to 50% by mass, based on the total mass of the surface layer. If it is less than 1% by mass, the effect of improving the durability of the toner and the toner carrier is insufficient, and 60% by mass
If it exceeds, the strength of the film is lowered, or the amount of light incident on the image carrier is significantly lowered, which is not preferable.

The present invention is particularly effective when the charging means is a direct charging method in which the charging member is brought into contact with the image carrier. Compared to corona discharge or the like in which the charging means does not come into contact with the image carrier, the load on the surface of the image carrier is large, so that the effect of improving the life of the image carrier is remarkable, which is one of the preferable application modes.

One of the preferred embodiments of the image carrier used in the present invention will be described below.

Examples of the conductive substrate include metals such as aluminum and stainless steel, aluminum alloys, and indium oxide.
Cylindrical cylinders and films of plastic having a coating layer of tin oxide alloy, paper impregnated with conductive particles, plastic, plastic having conductive polymer, and the like are used.

On these conductive substrates, the adhesion of the photosensitive layer is improved, the coating property is improved, the substrate is protected, and the defects on the substrate are covered.
An undercoat layer may be provided for the purpose of improving the charge injection property from the substrate and protecting the photosensitive layer against electrical breakdown. The subbing layer is polyvinyl alcohol, poly-N-vinyl imidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenol resin, casein, polyamide, copolymer nylon, glue,
It is formed of a material such as gelatin, polyurethane, aluminum oxide or the like. The film thickness is usually 0.1 to 10 μm,
It is preferably about 0.1 to 3 μm.

The charge generation layer includes azo pigments, phthalocyanine pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, squarylium dyes, pyrylium salts, thiopyrylium salts, triphenylmethane dyes, selenium,
It is formed by dispersing a charge generating substance such as an inorganic substance such as amorphous silicon in a suitable binder and coating or vapor depositing. The binder can be selected from a wide range of binder resins, for example, polycarbonate resin, polyester resin, polyvinyl butyral resin, polystyrene resin, acrylic resin, methacrylic resin, phenol resin, silicone resin, epoxy resin, vinyl acetate resin, etc. Is mentioned. The amount of the binder contained in the charge generation layer is 80% by mass.
Below, it is preferably selected to be 0 to 40% by mass. The film thickness of the charge generation layer is preferably 5 μm or less, and particularly preferably 0.05 to 2 μm.

The charge transport layer has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transport layer is formed by dissolving a charge transport substance in a solvent, if necessary, together with a binder resin, and coating the solution, and the film thickness thereof is generally 5 to 40 μm. As the charge transport substance, biphenylene is added to the main chain or side chain,
Polycyclic aromatic compounds having a structure such as anthracene, pyrene and phenanthrene, nitrogen-containing cyclic compounds such as indole, carbazole, oxadiazole and pyrazoline,
Hydrazone compounds, styryl compounds, selenium, selenium-
Tellurium, amorphous silicon, cadmium sulfide, etc. may be mentioned.

As the binder resin in which these charge transporting substances are dispersed, polycarbonate resin, polyester resin, polymethacrylate ester, polystyrene resin,
Examples thereof include resins such as acrylic resins and polyamide resins, organic photoconductive polymers such as poly-N-vinylcarbazole, and polyvinylanthracene.

A protective layer may be provided as the surface layer. As the resin for the protective layer, polyester, polycarbonate, acrylic resin, epoxy resin, phenol resin, or a curing agent of these resins may be used alone or in combination.
Used in combination of more than one species.

Further, conductive fine particles may be dispersed in the resin of the protective layer. Examples of the conductive fine particles include metals and metal oxides, and preferably zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin oxide coated titanium oxide, tin coated indium oxide, Antimony coating There are ultrafine particles such as tin oxide and zirconium oxide. These may be used alone or in combination of two or more. Generally, when the particles are dispersed in the protective layer, it is necessary that the particle size of the particles is smaller than the wavelength of the incident light in order to prevent scattering of the incident light by the dispersed particles, and the particles are dispersed in the protective layer in the present invention. The particle diameter of the conductive and insulating particles is preferably 0.5 μm or less. The content in the protective layer is preferably 2 to 90% by mass, more preferably 5 to 80% by mass, based on the total mass of the protective layer. The thickness of the protective layer is preferably 0.1 to 10 μm, more preferably 1 to 7 μm.

The surface layer can be applied by spray coating, beam coating or permeation coating of the resin dispersion liquid.

The contact transfer process applicable to the image forming method of the present invention will be specifically described below.

In the contact transfer step, the developed image is electrostatically transferred onto the transfer material while the transfer means is in contact with the electrostatic image carrier and the transfer material. The contact pressure of the transfer means is linear pressure. It is preferably 2.9 N / m (3 g / cm) or more, more preferably 19.6 N / m (20 g / cm).
That is all. The linear pressure as the contact pressure is 2.9 N / m (3
If it is less than g / cm), transfer deviation of the transfer material and transfer failure are likely to occur, which is not preferable.

As the transfer means in the contact transfer step, a device having a transfer roller or a transfer belt is used. The transfer roller is composed of at least a core metal and a conductive elastic layer, and the conductive elastic layer is made of urethane having a conductive material such as carbon dispersed therein or EPDM and has a volume resistance of 10 ⁶ to 1 1.
It is made of an elastic body of about 0 ¹⁰ Ωcm.

The present invention is particularly effectively used in an image forming apparatus in which the surface of the latent image carrier (photoreceptor) is an organic compound. That is, when the organic compound forms the surface layer of the photoconductor, the adhesiveness to the binder resin contained in the toner particles is better than that of other photoconductors using an inorganic material, and the transferability is further reduced. This is because there is a tendency to

Examples of the surface material of the photoreceptor according to the present invention include silicone resin, vinylidene chloride, ethylene-vinyl chloride, styrene-acrylonitrile, styrene-methyl methacrylate, styrene, polyethylene terephthalate and polycarbonate. Without being limited to these, other monomers or copolymers and blends between the above-mentioned binder resins can be used.

Further, the present invention is particularly effectively used for an image forming apparatus having a photoconductor having a small diameter of 50 mm or less. That is, in the case of a small-diameter photoconductor, the curvature with respect to the same linear pressure is large, and the pressure is likely to concentrate at the contact portion. Although it is considered that the same phenomenon occurs in the belt photoreceptor, the present invention has a radius of curvature of 25 at the transfer portion.
It is also effective for an image forming apparatus having a size of less than or equal to mm.

Further, the toner of the present invention is set so that the closest gap between the image carrier and the toner carrier is wider than the thickness of the toner layer on the toner carrier by means of the member for regulating the toner on the toner carrier. However, it is particularly preferable from the viewpoint of uniformly charging the toner that the member for regulating the toner on the toner carrier is regulated by the elastic member that is in contact with the toner carrier via the toner.

The surface roughness of the toner carrier used in the present invention is from 0.2 to JIS center line average roughness (Ra).
It is preferably in the range of 3.5 μm.

If Ra is less than 0.2 μm, the amount of charge on the toner carrier will be high and the developability will be insufficient. When Ra exceeds 3.5 μm, unevenness occurs in the toner coat layer on the toner carrier, resulting in uneven density on the image. More preferably, it is in the range of 0.5 to 3.0 μm.

Further, since the toner of the present invention has a high charging ability, it is desirable to control the total charge amount of the toner at the time of development, and the surface of the toner carrier according to the present invention contains conductive fine particles and / or a lubricant. It is preferably covered with a dispersed resin layer.

As the conductive fine particles contained in the resin layer coating the surface of the toner carrier, carbon black, graphite, conductive metal oxides such as conductive zinc oxide, and metal complex oxides may be used alone or in combination of two or more. It is preferably used. Further, as the resin in which the conductive fine particles are dispersed, a phenol resin, an epoxy resin, a polyamide resin, a polyester resin, a polycarbonate resin,
Known resins such as polyolefin resins, silicone resins, fluorine resins, styrene resins, and acrylic resins are used. A thermosetting or photocurable resin is particularly preferable.

When the one-component developing method is used in the present invention, the layer thickness smaller than the closest distance (between SD) between the toner carrier and the latent image carrier is obtained on the toner carrier in order to obtain high image quality. Then, it is preferable that the development is performed in a developing process in which the magnetic toner is applied and an alternating electric field is applied to perform the development.

Further, in the present invention, it is preferable in terms of environmental protection that the charging member and the transfer member are in contact with the photoconductor so that ozone is not generated.

A preferable process condition when a charging roller is used is that the contact pressure of the roller is 5 to 500 g /
cm, when using a DC voltage superimposed with an AC voltage, AC voltage = 0.5 to 5 kVpp, AC frequency =
50 to 5 kHz, DC voltage = ± 0.2 to ± 5 kV.

Other charging means include a method using a charging blade and a method using a conductive brush. These contact charging means have an effect that a high voltage is unnecessary and ozone generation is reduced.

As the material of the charging roller and the charging blade as the contact charging means, conductive rubber is preferable, and a releasing film may be provided on the surface thereof. As the releasable coating, nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), fluoroacrylic resin, etc. can be applied.

Next, the image forming method of the present invention will be specifically described with reference to the drawings.

In FIG. 1, a photosensitive drum 100 is provided with a primary charging roller 117, a developing device 140, a transfer charging roller 114, a cleaner 116, a register roller 124 and the like around the photosensitive drum. And the photosensitive drum 100
Is charged to −700 V by the primary charging roller 117 (applied voltage is AC voltage −2.0 kVpp, DC voltage −700 Vdc). Then, the laser light 123 is applied to the photosensitive drum 100 by the laser generator 121, so that the photosensitive drum 100 is exposed. The electrostatic latent image on the photosensitive drum 100 is developed with a one-component magnetic toner by the developing device 140,
Transfer roller 1 that is in contact with the photosensitive drum via the transfer material
It is transferred onto the transfer material by 14. The transfer material on which the toner image is placed is conveyed to the fixing device 126 by the conveyor belt 125 or the like and fixed on the transfer material. The toner partially left on the electrostatic latent image carrier is cleaned by the cleaning unit 116.

As shown in FIG. 2, the developing device 140 is provided with a cylindrical toner carrier 102 (hereinafter referred to as a developing sleeve) made of a non-magnetic metal such as aluminum or stainless steel in the vicinity of the photosensitive drum 100. The gap between the photosensitive drum 100 and the developing sleeve 102 is maintained at about 300 μm by a sleeve / drum gap holding member (not shown). A stirring rod 141 is arranged in the developing device. A magnet roller 104 is fixed and arranged concentrically with the developing sleeve 102 in the developing sleeve. However, the developing sleeve 102 is rotatable. The magnet roller 104 is provided with a plurality of magnetic poles as shown in the drawing. S ₁ influences development, N ₁ regulates toner coat amount, S ₂ influences toner intake / conveyance, and N ₂ influences toner blowout prevention. There is. The elastic blade 1 is used as a member for controlling the amount of magnetic toner attached to the developing sleeve 102 and conveyed.
03 is arranged and the developing sleeve 10 of the elastic blade 103
The amount of toner conveyed to the developing area is controlled by the contact pressure with respect to 2. In the developing area, a DC and AC developing bias is applied between the photosensitive drum 100 and the developing sleeve 102, and the toner on the developing sleeve flies on the photosensitive drum 100 according to the electrostatic latent image and becomes a visible image.

[0128]

EXAMPLES The present invention will be specifically described below with reference to production examples and examples, but the present invention is not limited thereto. In the following formulation, all parts are parts by mass.

[Magnetic Iron Oxide Production Example 1] Sodium silicate was added to an aqueous ferrous sulfate solution so that the content of silicon element was 1.9% with respect to iron element. 1.0 equivalent of a caustic soda solution was mixed to prepare an aqueous solution containing ferrous hydroxide. While maintaining the pH of the aqueous solution at approximately 9, air was blown in to carry out an oxidation reaction at 80 ° C. to prepare a slurry liquid for generating seed crystals which become the core of the magnetic iron oxide particles.

Next, 1.1 equivalents of aqueous ferrous sulfate solution was added to the initial amount of alkali (sodium component of sodium silicate and sodium component of caustic soda) to the slurry liquid, and then the pH of the slurry liquid was adjusted to 8 While maintaining the temperature to a certain level, the oxidation reaction was advanced while blowing air, the pH was adjusted at the end of the oxidation reaction, and the silicic acid component was unevenly distributed on the surface of the magnetic iron oxide. The generated magnetic iron oxide particles are washed, filtered, and
Magnetic iron oxide A which contains 1.9% by mass of silicon element based on the iron element after being dried and then subjected to an analysis treatment for loosening the agglomeration
I got

Fe / at the outermost surface of this magnetic iron oxide A
The Si atomic ratio was 4.0.

Further, Table 1 shows data obtained by measuring the dissolved amounts of the iron element and the silicon element every 10 minutes. From this, the content b of the silicon element present in the iron oxide dissolution rate of the magnetic iron oxide up to 20% by mass is about 37.8 mg / liter, and the total content a of the silicon element of the magnetic iron oxide a is 62.2 mg / liter. Ratio (b / a) × 100 is 60.8%, and the content c of the silicon element derived from the silicon compound existing on the surface of the magnetic iron oxide eluted with alkali is 16.2 mg / liter. Ratio of total content a (c / a) x 100 is 2
It was 6.0%.

[Magnetic Iron Oxide Production Examples 2 and 3] In the magnetic iron oxide production example 1, the content ratio of the silicon element to the iron element was 0.5%.
And magnetic iron oxides B and C were obtained in the same manner as in Magnetic Iron Oxide Production Example 1 except that sodium silicate was added so that the contents became 3.8%. Table 3 shows the characteristics of magnetic iron oxides B and C.

[Magnetic Iron Oxide Production Example 4] An aqueous solution containing ferrous hydroxide was prepared by mixing 0.95 equivalent of caustic soda solution with iron ion in the aqueous ferrous sulfate solution. After that, the sodium silicate was converted into 1.
It was added so as to be 2%. Next, magnetic iron oxide particles containing silicon elements were produced by aerating air at 90 ° C. in an aqueous ferrous salt solution containing iron hydroxide to carry out an oxidation reaction.

Furthermore, 0.2% of sodium silicate was added to this slurry.
1.05 equivalents of caustic soda aqueous solution in which (converted to elemental silicon with respect to elemental silicon) was dissolved were added to remaining iron ions, and further oxidation reaction was carried out while heating at a temperature of 90 ° C. to contain elemental silicon. Magnetic iron oxide particles were produced.

The produced magnetic iron oxide particles were washed by a conventional method, filtered, dried, and then crushed to loosen the agglomerates, and magnetic iron oxide containing 1.4 mass% of silicon element based on the iron element was used. I got D.

Fe / at the outermost surface of this magnetic iron oxide D
The Si atomic ratio was 1.7.

Further, Table 2 shows data obtained by measuring the dissolved amounts of the iron element and the silicon element every 10 minutes. From this, the content b of the silicon element present in the iron oxide dissolution rate of the magnetic iron oxide up to 20% by mass is about 28.4 mg / liter, and the total content a of the silicon element of the magnetic iron oxide a is 48.9 mg / liter. The ratio (b / a) × 100 is 58.1%, which is the ratio (c / a) between the content c of 7.3 mg / liter of the silicon element present on the surface of the magnetic iron oxide and the total content a of the silicon element. × 100
Was 14.9%.

[Magnetic Iron Oxide Production Examples 5 to 7] After washing the magnetic iron oxide particles produced in Magnetic Iron Oxide Production Example 4 by a conventional method, the magnetic iron oxide was added to the magnetic iron oxide as aluminum element in the slurry before filtration. Aluminum sulfate was added to adjust the pH to about 7 and aluminum oxide was used for the surface treatment of magnetic iron oxide.

When performing the surface treatment, the amount of aluminum sulfate was set to 0.05 and the content ratio of aluminum element to iron element was set to 0.05.
%, 0.3% and 1.8%, the case of adding sodium silicate was then filtered and dried in the same manner as in Magnetic Iron Oxide Production Example 4, and then subjected to a crushing treatment to loosen agglomerates. , Magnetic iron oxides E, F and G were obtained. Table 3 shows the characteristics of the magnetic iron oxides E, F and G.

[Magnetic Iron Oxide Production Example 8] 1.1 equivalent of caustic soda solution and 0.05 equivalent of aluminum sulfate aqueous solution were mixed with ferrous sulfate aqueous solution to prepare ferrous hydroxide. An aqueous solution containing it was prepared. Blow air,
An oxidation reaction was performed at 80 ° C. to generate magnetic iron oxide particles.

The produced magnetic iron oxide particles are washed, filtered and dried by a conventional method, and then subjected to a crushing treatment to loosen the agglomerates.
Magnetic iron oxide H containing 2.4 mass% of aluminum element based on iron element was obtained.

Fe / on the outermost surface of this magnetic iron oxide H
The Al atomic ratio was 2.5.

[Magnetic Iron Oxide Production Example 9] An aqueous solution containing ferrous hydroxide was prepared by mixing 1.05 equivalent of caustic soda solution with iron ions in the aqueous ferrous sulfate solution. Air was passed through the ferrous salt aqueous solution containing iron hydroxide at 90 ° C. to carry out an oxidation reaction to produce magnetic iron oxide particles substantially containing no silicon element and no aluminum element.

The produced magnetic iron oxide particles are washed, filtered and dried by a conventional method, and then subjected to a crushing treatment to loosen the agglomerates.
Magnetic iron oxide I containing substantially no silicon element and aluminum element was obtained.

[0146]

[Table 1]

[0147]

[Table 2]

[0148]

[Table 3]

(Toner Production Example 1) Magnetic Iron Oxide A (Magnetic Iron Oxide Production Example 1) 100 parts Styrene-butyl acrylate-butyl maleate half ester copolymer (Low molecular weight side peak: about 8,000, glass transition Point Tg: 60 ° C) 100 parts-Chromium complex of monoazo dye (negative charge control agent) 1 part-Low molecular weight polyolefin (release agent) 2 parts

The above materials were mixed in a blender,
Melted and kneaded with a twin-screw extruder heated to ℃, cooled and crushed the kneaded material roughly with a hammer mill, finely crushed the coarsely crushed material with a jet mill, and the resulting finely crushed material is multi-divided using the Coanda effect. Strict classification was carried out with a classifier to obtain magnetic toner particles. The magnetic toner particles were subjected to a surface treatment by a thermo-mechanical impact force (treatment temperature 60 ° C.), and the obtained magnetic toner particles were treated with 1.8% by mass of silicone oil and hexamethyldisilazane to make them hydrophobic. Dry silica having a diameter of 12 nm (BET specific surface area after treatment, 120 m ² / g) was added and mixed by a mixer to obtain a magnetic toner A.

The weight average particle diameter of the obtained magnetic toner is 6.
7 μm, number average particle diameter is 5.3 μm, SF-1 is 13
8, SF-2 is 130, BET specific surface area is 5.4 m ² /
It was cm ³ . The BET specific surface area of the toner particles was 1.8 m ² / cm ³ . Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Examples 2 and 3) Magnetic toners B and C were obtained in the same manner as in Toner Production Example 1 except that the magnetic iron oxides B and C of Magnetic Iron Oxide Production Examples 2 and 3 were used as the magnetic iron oxides. It was Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 4) Magnetic Iron Oxide D (Magnetic Iron Oxide Production Example 4) 100 parts Styrene-butyl acrylate-butyl maleate half ester copolymer (Low molecular weight side peak: about 5000, glass transition Point Tg: 58 ° C) 100 parts-Chromium complex of monoazo dye (negative charge control agent) 1 part-Low molecular weight polyolefin (release agent) 2 parts

Using the above materials, setting the treatment temperature of the toner particles by thermo-mechanical impact to 64 ° C., and using dry silica (BET specific surface area 100 m) having a primary particle size of 8 nm which has been hydrophobized with silicone oil as an inorganic fine powder. ² / g)
Of 1.8% by mass and 0.5% by mass of spherical silica (BET
A magnetic toner D having a weight average particle size of 7.0 μm was obtained in the same manner as in Toner Production Example 1 except that a specific surface area of 20 m ² / g and a primary particle size of 0.1 μm) were used. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Examples 5, 6 and 7) Magnetic Iron Oxide as Magnetic Iron Oxide Magnetic Iron Oxide E of Production Examples 5, 6 and 7
Magnetic toners E, F and G were obtained in the same manner as in Toner Production Example 4 except that F and G were used. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 8) -Magnetic iron oxide H (Magnetic iron oxide Production Example 8) 110 parts-Polyester resin (low molecular weight side peak: about 7,000, glass transition point Tg: 63 ° C) 100 parts-Monoazo dye Chromium complex (negative charge control agent) 1 part ・ Low molecular weight polyolefin (release agent) 2 parts

A weight average particle diameter of 6.6 μm was obtained in the same manner as in Toner Production Example 1 except that the above materials were used and the processing temperature of the toner particles by thermomechanical impact was 64 ° C.
Magnetic toner H of No. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Examples 9 and 10) A magnetic toner I and a magnetic iron oxide I were used in the same manner as in the toner production example 1 except that the magnetic iron oxide prepared in Production Example 9 was used as the magnetic iron oxide. Magnetic Toner J was obtained in the same manner as in Toner Production Example 8 except that the above was used. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 11) As an inorganic fine powder,
Dry silica (BET specific surface area 120 m ² / g) having a primary particle diameter of 12 nm that has been hydrophobized with 1.8% by mass of silicone oil and hexamethyldisilazane, and 0.3% by mass of spherical silica (BET specific surface area of 5 m ² / g, primary particle size 1.
Magnetic toner K was obtained in the same manner as in Toner Production Example 1 except that 0 μm) was added. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 12) The magnetic toner particles obtained in Toner Production Example 1 were hydrophobized with 1.2% by weight of hexamethyldisilazane to obtain a primary particle diameter of 12 n.
m dry silica (BET specific surface area 160 m ² / g) was added and mixed by a mixer to obtain a magnetic toner L. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Examples 13 and 14) As an inorganic fine powder, a primary particle size of about 2 which was hydrophobized with silicone oil was used.
0 nm titanium oxide fine particles (BET specific surface area 100 m ²
/ G), alumina fine particles with a primary particle size of about 20 nm (BET
Magnetic toners M and N were obtained in the same manner as in Toner Production Example 1 except that 1.0% by mass of the specific surface area of 90 m ² / g) was used. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 15) A magnetic toner O was obtained in the same manner as in Toner Production Example 1 except that the surface treatment by thermo-mechanical impact was not performed. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 16) Magnetic Iron Oxide A (Magnetic Iron Oxide Production Example 1) 60 parts Styrene-butyl acrylate copolymer (low molecular weight side peak: about 18,000, glass transition point Tg: 71 ° C.) 100 parts-Chromium complex of monoazo dye (negative charge control agent) 1 part-Low molecular weight polyolefin (release agent) 2 parts

The above materials were mixed in a blender,
Melted and kneaded with a twin-screw extruder heated to ℃, cooled and crushed the kneaded material roughly with a hammer mill, finely crushed the coarsely crushed material with a jet mill, and the resulting finely crushed material is multi-divided using the Coanda effect. Strict classification was carried out with a classifier to obtain magnetic toner particles. 0.5% by mass based on the obtained magnetic toner particles
Dry silica having a primary particle size of about 16 nm that has been hydrophobized with hexamethyldisilazane (BET specific surface area after treatment 10
0 m ² / g) and mixed with a mixer to obtain magnetic toner P
I got The weight average particle diameter of the obtained magnetic toner P is 12.
It was 7 μm. Table 4 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 17) In the same manner as in Toner Production Example 1 except that the inorganic fine powder was not added to the toner particles,
A magnetic toner Q was obtained. The physical properties of the obtained magnetic toner are shown in Table 4.
Shown in

(Toner Production Example 18) In Toner Production Example 1, the inorganic fine powder was hydrophobized with 1.8% by mass of silicone oil and hexamethyldisilazane to obtain a primary particle size of 1
2 nm dry silica (BET specific surface area after treatment 120 m
² / g) and 0.5% by mass of hexamethyldisilazane and treated with Production Example 1 except that dry silica having a primary particle size of 40 nm that has been hydrophobized (BET specific surface area after treatment 40 m ² / g) is used. A magnetic toner R was obtained in the same manner. Table 4 shows the physical properties of the obtained magnetic toner.

[0167]

[Table 4]

<Photoreceptor Production Example 1> As a photoreceptor, the diameter is 3
The base was a 0 mm Al cylinder. A layer having a structure as shown in FIG. 3 was sequentially laminated thereon by dip coating to prepare a photoconductor.

(1) Conductive coating layer: Mainly composed of tin oxide and titanium oxide powder dispersed in a phenol resin. Film thickness 15 μm.

(2) Undercoat layer: Mainly composed of modified nylon and copolymer nylon. The film thickness is 0.6 μm.

(3) Charge generation layer: Mainly composed of an azo pigment having absorption in the long wavelength region dispersed in butyral resin. The film thickness is 0.6 μm.

(4) Charge transport layer: Mainly composed of a hole-transporting triphenylamine compound dissolved in a polycarbonate resin (molecular weight of 20,000 by Oswald viscosity method) at a mass ratio of 8:10, and further polytetrafluoroethylene. 10% by mass of powder (particle size: 0.2 μm) was added to the total solid content and uniformly dispersed. The film thickness is 25 μm. The contact angle with water was 95 degrees.

Pure water was used to measure the contact angle, and a contact angle meter CA-DS type manufactured by Kyowa Interface Science Co., Ltd. was used as the apparatus.

<Photoreceptor Production Example 2> A photoconductor was produced in the same manner as in Photoreceptor Production Example 1 without adding polytetrafluoroethylene powder. The contact angle with water was 74 degrees.

<Photoreceptor Production Example 3> A photoconductor was produced according to Photoreceptor Production Example 1 up to the charge generation layer. For the charge transport layer, a hole-transporting triphenylamine compound dissolved in a polycarbonate resin at a mass ratio of 10:10 was used. Film thickness 20 μm. Furthermore, as a protective layer, a polytetrafluoroethylene powder (particle size: 0.2 μm) was added to the composition obtained by dissolving the same material in a mass ratio of 5:10 in an amount of 30% with respect to the total solid content to obtain a uniform mixture. Was spray-coated on the charge transport layer. Film thickness 5 μm. The contact angle with water was 102 degrees.

Example 1 The image forming apparatus shown in FIGS. 1 and 2 was used.

As an electrostatic latent image carrier, the organic photoconductor (OPC) drum of Photoconductor Production Example 3 was used and the dark portion potential V _d = -70.
0V and bright part potential _VL = -210V. A gap between the photosensitive drum and the developing sleeve is 300 μm, a toner carrier having a layer thickness of about 7 μm and a JIS center line average roughness (Ra) of 0.8 μm is used as a toner carrier, and a surface is a mirror surface having a diameter of 16φ. Using a developing sleeve formed on an aluminum cylinder, a developing magnetic pole of 95 mT (950 gauss), a toner regulating member having a thickness of 1.0 mm and a urethane rubber blade having a free length of 10 mm, 14.7 N / m (15 g / cm).
It was made to contact by the linear pressure.

Phenolic resin 100 parts Graphite (particle size about 7 μm) 90 parts Carbon black 10 parts

Next, as a developing bias, a DC bias component V _dc = -500V, and an AC bias component V to be superimposed.
_PP = 1200V and f = 2000Hz were used. Also,
The peripheral speed of the developing sleeve is the peripheral speed of the photoconductor (48 mm / sec).
150% in the forward direction (reverse as the rotation direction)
Speed (72 mm / sec).

A transfer roller as shown in FIG. 7 (made of ethylene-propylene rubber in which conductive carbon is dispersed, volume resistance value of conductive elastic layer 10 ⁸ Ωcm, surface rubber hardness 24)
°, diameter 20 mm, contact pressure 49 N / m (50 g / cm)
Equal to the peripheral speed of the photoconductor (48 mm / sec),
+2000 V was applied as the transfer bias, the magnetic toner A was used as the toner, and the image was printed in the environment of 23 ° C. and 65% RH. As the transfer paper, 75 g / m ² paper was used.

At this time, the transfer efficiency from the photosensitive member to the transfer material was as high as 96%, and there was no dropout of characters or lines in the transfer, and a good image without scattering on the image was obtained.

In the present invention, the evaluation of scattering is as follows.
It is a splattering evaluation in fine fine lines related to the image quality of a graphical image, and a splattering evaluation in a 100 μm wide line, which is more likely to scatter than characters and lines.

The transferability was evaluated by a numerical value obtained by subtracting the Macbeth density of the one with the tape only from the Macbeth density of the one with the transfer toner on the solid black photoconductor taped and stripped off with Mylar tape and stuck on the paper. did.

Further, even under the low temperature and low humidity environment of 15 ° C. and 10% RH, images were continuously printed up to 1000 sheets, but the toner coat on the toner carrier was uniform, and good images without image defects were obtained. Was obtained.

Example 2 Image formation was performed under the same apparatus and conditions as in Example 1 except that the OPC drum of Photoreceptor Manufacturing Example 1 was used as the electrostatic latent image bearing member. At this time, the transfer efficiency from the photoconductor to the transfer material is 93.
%, A good transfer efficiency was exhibited, characters and lines were not missing in the transfer, and a good image without scattering was obtained. Even in the continuous 1000-sheet image output test under a low temperature and low humidity environment, a good image without image defects was obtained as in Example 1.

Image formation was performed under the same apparatus and conditions as in Example 1 except that Toner B of Toner Production Example 2 and Toner C of Toner Production Example 3 were used as the toners of Examples 3 and 4 .

At this time, the transfer efficiency from the photosensitive member to the transfer material was as high as 95% and 96%, and there was no void in the transfer of characters or lines, and a good image without scattering on the image was obtained. It was Even in the continuous 1000-sheet image output test under a low temperature and low humidity environment, a good image having no image defect similar to that in Example 1 was obtained.

Comparative Example 1 Image formation was performed under the same apparatus and conditions as in Example 1 except that Toner I manufactured by Toner Production 9 was used as the toner. As a result, the transfer efficiency from the photoconductor to the transfer material was almost good, but in the continuous 1000-sheet image output test under the low temperature and low humidity environment of 15 ° C. and 10% RH, the developing property was slightly improved at the end of the test. The image density was inferior to that of Example 1, and the image density was low. Further, in a solid image after 1000 sheets were continuously printed in a low-temperature and low-humidity environment, unevenness in image density, which is considered to be caused by a defective toner coat on the toner carrier, was generated.

Examples 5 to 8 As a black toner carrier, a layer thickness of about 7 μm having the following constitution, JI
A developing sleeve was prepared in which a resin layer having an S center line average roughness (Ra) of 1.5 μm was formed on a stainless steel cylinder having a diameter of 16φ whose surface was blasted.

-Phenol resin 100 parts-Graphite (particle size of about 3 μm) 45 parts-Carbon black 5 parts

Using the developing sleeve and the magnetic toners D, E, F and G of the toner manufacturing examples 4 to 7 as the black toner, the DC bias component Vdc = -500 is used as the developing bias.
V, AC bias component to be superimposed Vpp = 1100V, f
= 2000 Hz, the ratio Vt / V of the peripheral speed Vt of the developing sleeve to the peripheral speed of the photoconductor was set to 2.0, and image formation was performed under the same apparatus and conditions as in Example 1 except that the toner was rotated in the forward direction.
As a result, the transfer efficiency from the photoconductor to the transfer material is 9 each.
High transfer efficiency of 6%, 97%, 98%, 98%,
In each case, the transfer efficiency was as good as that of Example 1 or higher, and a good image was obtained in which there were no voids in the transfer of characters or lines and there was no scattering on the image.

In a continuous 1000-sheet image output test under a low temperature and low humidity environment of 15 ° C. and 10% RH, good developing properties were shown in all cases.
The image densities of F and G were higher, and particularly, the magnetic toners F and G had high uniformity even after continuous 1000 sheets under low temperature and low humidity environment, and a high-quality solid image was obtained.

Comparative Example 2 Image formation was carried out under the same apparatus and conditions as in Example 1 except that Toner J of Toner Production Example 10 was used as the magnetic toner. As a result, the transfer efficiency from the photoconductor to the transfer material was slightly worse than that in Example 1, but was almost good.
In a continuous 1000-sheet image output test under a low temperature and low humidity environment of 10 ° C. and 10% RH, the developability was slightly inferior to that of Example 1 at the end of the test, and the image density was low. Further, in a solid image after 1000 sheets were continuously printed in a low-temperature and low-humidity environment, unevenness in image density, which is considered to be caused by a defective toner coat on the toner carrier, was generated.

Example 9 Image formation was carried out under the same apparatus and conditions as in Example 1 except that the magnetic toner H of Toner Production Example 8 was used as the toner.
As a result, the transfer efficiency from the photoconductor to the transfer material was 94%, which was almost the same as in Example 1 and a good transfer efficiency was obtained, and there was no void in the transfer of characters or lines, and a good image without scattering was obtained. It was Further, even in a low-temperature and low-humidity environment, stable toner coatability was exhibited, good developability and durability were exhibited, and a solid image was also highly uniform with no image defects.

Example 10 The magnetic toner K of Toner Production Example 11 was used as the toner, and the DC bias component Vdc = -4 as the developing bias.
50V, AC bias component to be superimposed Vpp = 1300
Image formation is performed under the same apparatus and conditions as in Example 1 except that V and f = 2000 Hz, and the transfer efficiency from the photoconductor to the transfer material is 96%, which is the same as or better than Example 1. It shows efficiency and there are no omissions in the transfer of letters and lines,
A good image without scattering was obtained on the image. Also,
Even in a low temperature and low humidity environment, the toner coat property was stable, good developability and durability were exhibited, and the solid image was also highly uniform with no image defects.

Example 11 Image formation was carried out under the same apparatus and conditions as in Example 1 except that the magnetic toner L of Toner Production Example 12 was used as the toner. As a result, the transfer efficiency from the photoconductor to the transfer material is 94%.
In the same manner as in Example 1, a good image having good transfer efficiency, no voids in the transfer of characters or lines, and no scattering on the image was obtained. Further, even in a low-temperature and low-humidity environment, stable toner coatability was exhibited, good developability and durability were exhibited, and a solid image was also highly uniform with no image defects.

Example 12 Image formation was carried out in the same apparatus and conditions as in Example 1 except that the magnetic toner M of Toner Production Example 13 was used as the toner. As a result, the transfer efficiency from the photoconductor to the transfer material is 92%.
With good transfer efficiency, there is no omission of characters or lines in the transfer,
A good image without scattering was obtained on the image. Also,
Even in a low temperature and low humidity environment, the toner coat property was stable, good developability and durability were exhibited, and the solid image was also highly uniform with no image defects.

Example 13 Image formation was carried out under the same apparatus and conditions as in Example 1 except that the magnetic toner N of Toner Production Example 14 was used as the toner. As a result, the transfer efficiency from the photoconductor to the transfer material is 90%.
With good transfer efficiency, there is no omission of characters or lines in the transfer,
A good image without scattering was obtained on the image. Also,
Even in a low temperature and low humidity environment, the toner coat property was stable, good developability and durability were exhibited, and the solid image was also highly uniform with no image defects.

Comparative Example 3 Images were produced under the same apparatus and conditions as in Example 2 except that Toner O of Toner Production Example 15 was used as the toner. As a result, the transfer efficiency from the photoconductor to the transfer material was 85%, the transfer efficiency was poorer than that in Example 2, and the images were slightly defective in the transfer of characters and lines.

Comparative Example 4 Images were produced under the same apparatus and conditions as in Example 2 except that the magnetic toner P of Toner Production Example 16 was used as the toner. As a result, the characters and lines were scattered a little, and the transfer efficiency from the photosensitive member to the transfer material was 83%, which was inferior to the transfer efficiency of Example 2, and an image in which transfer voids of characters and lines were conspicuous was obtained. Was given. Further, although the image density was stable even when continuously used in a low temperature and low humidity environment, the image density was low as compared with Example 1.

Comparative Example 5 As the toner, the magnetic toner Q of Toner Production Example 17 is used,
Image formation was performed under the same apparatus and conditions as in Example 1 except that the OPC drum of Photoreceptor Production Example 2 was used as the electrostatic latent image carrier. As a result, the transfer efficiency from the photoconductor to the transfer material was 74%, which was lower than that in Example 1, and the voids in the transfer of characters and lines were slightly observed.

Although image defects such as density unevenness of a solid image did not occur even after continuous use in a low temperature and low humidity environment, the image density tended to decrease.

Example 14 Image formation was carried out under the same apparatus and conditions as in Example 1 except that Toner R of Toner Production Example 18 was used as the toner.
At this time, the transfer efficiency from the photoconductor to the transfer material was as high as 96%, which was high, and there was no dropout of characters or lines in the transfer, and a good image without scattering was obtained.

[0204]

According to the present invention, in a toner having toner particles containing at least a binder resin and magnetic iron oxide and an inorganic fine powder, the magnetic iron oxide contains (a) a silicon element based on an iron element. 0.4 to 4% by mass or (b) 0.05 to 10% by mass of aluminum element based on iron element, or both of silicon element and aluminum element in the above ratio, The value of the shape factor SF-1 measured by the image analyzer is 110 <SF-1 ≦ 180,
The value of the shape factor SF-2 is 110 <SF-2 ≦ 140, the value of the ratio B / A is 1.0 or less, and the BE of the toner is
Specific surface area Sb per unit volume measured by T method
(M ² / cm ³ ) and the specific surface area St (m) per unit volume calculated from the weight average particle diameter when the toner is assumed to be a true sphere.
² / cm ³ ) on the toner and the electrostatic latent image bearing member, which satisfy the following condition 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5 An electrophotographic apparatus having a developing step of forming a toner image using the toner, and a transfer step of transferring the toner image onto the transfer material while bringing a transfer member to which a voltage is applied into contact with the transfer material. By using the image forming method to be used, it is possible to improve the void in transfer and the transfer efficiency while maintaining high image density and latent image reproducibility. further,
The charge controllability of the toner is improved more than before, and even with continuous image formation in a low-temperature and low-humidity environment, the uniformity of the toner thin layer coat on the toner carrier can be obtained, and there is no blur / wavy unevenness on the solid image. A high-quality and sharp image without image defects can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an image forming apparatus suitable for the present invention.

FIG. 2 is a schematic view showing an example of a developing unit for one-component development.

FIG. 3 is a schematic view showing an example of the configuration of a photoconductor used in the present invention.

FIG. 4 is a schematic view of a charge amount measuring device for measuring the charge amount of toner used in the present invention.

FIG. 5 is a diagram showing a good image (a) having no “transfer blank area” and a defective image (b) having “transfer blank area”.

FIG. 6 is a diagram showing a range of the present invention in shape factors SF-1 and SF-2.

FIG. 7 is a schematic view showing an example of a contact transfer member.

[Explanation of symbols]

 100 Photoconductor (electrostatic latent image carrier) 102 Development sleeve (toner carrier) 103 Contact blade 104 Magnet roller 114 Transfer charging roller 116 Cleaner 117 Primary charging roller 140 Developer 141 141 Stirring bar

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location G03G 9/08 375 (72) Inventor Keita Nozawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Yuki Nishio 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (35)

[Claims] 1. A toner having toner particles containing at least a binder resin and magnetic iron oxide, and inorganic fine powder, wherein the magnetic iron oxide contains (a) a silicon element in an amount of 0.4 to 4 mass. % Or (b) 0.05 to 10% by mass of aluminum element based on iron element, or both of silicon element and aluminum element in the above ratio, and measured by an image analyzer of the toner. The value of the shape factor SF-1 is 110 <SF-1 ≦ 180, and the shape factor SF−
2 is 110 <SF-2 ≦ 140, and the ratio B / A of the value B obtained by subtracting 100 from the value of SF-2 and the value A obtained by subtracting 100 from the value of SF-1 is 1. 0 or less, and the specific surface area Sb (m ² / cm ³ ) per unit volume of the toner measured by the BET method, and the unit surface area per unit volume calculated from the weight average particle diameter when the toner is assumed to be a true sphere. A toner having a specific surface area St (m ² / cm ³ ) satisfying the following conditions: 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5. 2. Fe / S on the outermost surface of the magnetic iron oxide
The toner according to claim 1, wherein the i atomic ratio is 1.2 to 4.0. 3. Fe / A on the outermost surface of the magnetic iron oxide
The toner according to claim 1 or 2, wherein the 1 atomic ratio is 0.3 to 10.0. 4. The ratio (b / a) of the content b of the silicon element present in the magnetic iron oxide having an iron element dissolution rate of up to 20% by mass and the total content a of the silicon iron element of the magnetic iron oxide × 100 is 44 ~
84%, which is the ratio (c / a) of the content c of the silicon element existing on the surface of the magnetic iron oxide to the total content a of the silicon element x
100 is 10-55%, It is characterized by the above-mentioned.
4. The toner according to any one of 3 to 3. 5. The toner according to claim 1, wherein the toner is a magnetic toner containing 30 to 200 parts by mass of a magnetic material with respect to 100 parts by mass of a binder resin. 6. SF measured by an image analyzer of the toner
The value of -1 is 120-160, and the value of SF-2 is 115-140.
The toner according to any one of 1. 7. The inorganic fine powder contained in the toner is one or more kinds of inorganic fine powder selected from titania, alumina, silica or a double oxide thereof. The toner according to any one. 8. The inorganic fine powder contained in the toner is hydrophobized.
The toner according to. 9. The toner according to claim 8, wherein the hydrophobic inorganic fine powder contained in the toner is at least treated with silicone oil. 10. The inorganic fine powder contained in the toner has a primary particle diameter of 30 nm or less, and the toner is
The toner according to any one of claims 7 to 9, further comprising fine powder having a particle size of more than 30 nm. 11. The toner according to claim 10, wherein the fine powder exceeding 30 nm is an inorganic fine powder. 12. The toner according to claim 10, wherein the fine powder having a particle size exceeding 30 nm is a resin fine powder. 13. The toner according to claim 10, wherein the fine powder having a particle size of more than 30 nm is substantially spherical. 14. In the molecular weight distribution of the toner measured by GPC, the peak on the low molecular weight side is 3000 to 150.
The toner according to any one of claims 1 to 13, which is in a range of 00. 15. The specific surface area per volume of the toner particles measured by the BET method is 1.2 to 2.5 m ² / c.
15. The toner according to claim 1, wherein the toner is m ³ . 16. A 60% pore radius in an integrated pore area ratio curve of pores of 1 nm to 100 nm of the toner particles is 3.5 nm or less.
5. The toner according to any one of 5. 17. A developing step of forming a toner image on an electrostatic latent image carrier, and a transfer of transferring the toner image onto the transfer material while bringing a transfer member to which a voltage is applied into contact with the transfer material. In the image forming method using an electrophotographic apparatus having a step, the toner is a toner having toner particles containing at least a binder resin and magnetic iron oxide and an inorganic fine powder, and the magnetic iron oxide is (a) a silicon element. Based on the iron element.
4 to 4 mass% or (b) 0.05 to 10 mass% of aluminum element based on iron element, or both of silicon element and aluminum element in the above proportions, and image analysis of the toner The value of the shape factor SF-1 measured by the apparatus is 110 <SF-1 ≦ 180, and the shape factor SF−
2 is 110 <SF-2 ≦ 140, and the ratio B / A of the value B obtained by subtracting 100 from the value of SF-2 and the value A obtained by subtracting 100 from the value of SF-1 is 1. 0 or less, and the specific surface area Sb (m ² / cm ³ ) per unit volume of the toner measured by the BET method, and An image forming method characterized in that the relationship of the specific surface area St (m ² / cm ³ ) satisfies the following conditions 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5. 18. Fe / at the outermost surface of the magnetic iron oxide
The toner according to claim 17, wherein the Si atomic ratio is 1.2 to 4.0. 19. Fe / at the outermost surface of the magnetic iron oxide
The toner according to claim 17 or 18, wherein the Al atomic ratio is 0.3 to 10.0. 20. The ratio (b / a) of the content b of the silicon element present in the magnetic iron oxide having an iron element dissolution rate of up to 20 mass% and the total content a of the silicon element of the magnetic iron oxide × 100 is 44
Is 84% and the ratio (c / a) of the content c of the silicon element existing on the surface of the magnetic iron oxide to the total content a of the silicon element.
The toner according to any one of claims 17 to 19, wherein x100 is 10 to 55%. 21. The image forming method according to claim 17, wherein the toner is a magnetic toner containing 30 to 200 parts by mass of a magnetic material with respect to 100 parts by mass of a binder resin. . 22. S measured by an image analyzer of the toner
22. The image forming method according to claim 17, wherein the value of F-1 is 120 to 160, and the value of SF-2 is 115 to 140. 23. The inorganic fine powder contained in the toner is one or more kinds of inorganic fine powder selected from titania, alumina, silica or a complex oxide thereof. The image forming method according to any one of claims. 24. The image forming method according to claim 23, wherein the inorganic fine powder contained in the toner is hydrophobized. 25. The image forming method according to claim 24, wherein the hydrophobized inorganic fine powder contained in the toner is at least treated with silicone oil. 26. The inorganic fine powder contained in the toner has a primary particle diameter of 30 nm or less, and the toner is
26. The image forming method according to claim 17, further comprising a fine powder having a particle size exceeding 30 nm. 27. The image forming method according to claim 26, wherein the fine powder exceeding 30 nm is an inorganic fine powder. 28. The image forming method according to claim 26, wherein the fine powder exceeding 30 nm is a resin fine powder. 29. The image forming method according to claim 20, wherein the fine powder having a particle size of more than 30 nm is substantially spherical. 30. In the molecular weight distribution of the toner measured by GPC, the peak on the low molecular weight side is 3000 to 150.
30 to 30 inclusive.
The image forming method according to any one of 1. 31. The specific surface area per volume of the toner particles measured by the BET method is 1.2 to 2.5 m ² / c.
The image forming method according to claim 17, wherein the image forming method is m ³ . 32. The 60% pore radius in an integrated pore area ratio curve of pores of 1 nm to 100 nm of the toner particles is 3.5 nm or less. Image forming method. 33. The contact angle of the surface of the electrostatic latent image bearing member is 8
33. The image forming method according to claim 17, wherein the image forming angle is 5 degrees or more. 34. The image forming method according to claim 33, wherein the surface of the latent electrostatic image bearing member contains a substance containing fluorine. 35. The image forming method according to claim 34, wherein the substance containing fluorine on the surface of the electrostatic latent image carrier is fine powder containing fluorine.