JP2000206731A - Toner and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner superior in developing performance and so excellent in durability that it can maintain a high resolution image even after many copied images or printer images are outputted. SOLUTION: The toner has toner particles containing at least a binding resin and a colorant and fine particles of an inorganic compound comprising at least a phosphoric acid compound. Ions of a metal selected from at least the alkaline earth metals are contained as a cation constituting the inorganic compound. The inorganic compound contains two or more kinds of cation and at least one kind of the cations is ions of a metal selected from groups IB and VIII metals. The inorganic compound may be slightly water-soluble fine particles based on phosphate of an alkaline earth metal part of which has been substituted by a metal selected from the groups IB and VIII metals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in a recording method utilizing an electrophotographic method, an electrostatic recording method, a magnetic recording method, a toner jet recording method, and the like, and an image forming method. More specifically, the present invention relates to a toner used in a copying machine, a printer, and a facsimile, which forms a toner image on an electrostatic latent image carrier in advance and then transfers the image on a transfer material to form an image, and an image forming method.

[0002]

2. Description of the Related Art Conventionally, many methods have been known as electrophotography, but generally, a latent image carrier made of a photoconductive substance, that is, a so-called photoconductor, is charged by a charging member such as corona charging or a charging roller. After uniformly charging the surface of
An electric latent image is formed on the latent image carrier by irradiation of light energy or the like, and then the latent image is developed with a positively or negatively charged toner to be a visible image. After transferring the toner image to the transfer material, the toner image is fixed on the transfer material by energy such as heat and pressure to obtain a copy. The remaining toner that has not been transferred to the transfer material during transfer is cleaned by various methods, and the above-described steps are repeated.

As a method for visualizing an electric latent image with toner, a cascade developing method, a magnetic brush developing method used by mixing with a carrier, a non-magnetic one-component developing method, a pressure developing method, and the like are known. . Further, a magnetic one-component developing method in which a magnetic toner is used, and a rotating sleeve having a magnetic pole disposed at the center is used to fly between the photosensitive member and the sleeve by an electric field is also used. The toner used in each case is charged by frictional charging with a charging member such as a sleeve or a carrier.

[0004] In recent years, in image forming apparatuses such as printers and copiers by electrophotography, higher resolution has come as a technical direction, and higher definition has also been required in developing systems. ing. In addition, the functions of the copying machine have been advanced, and thus the digital copying machine has been moving toward the digitization. In this direction, a method of forming an electrostatic charge image with a laser is mainly used, so that the direction is also moving toward a higher resolution, and a high-resolution and high-definition developing method is required similarly to a printer. .

In particular, in recent years, as the electrophotographic color image forming apparatus has become widespread, its use has been expanded in various ways.
The demands on the image quality have also become severe. When copying images such as ordinary photos, catalogs, and maps, even the smallest details are not crushed or interrupted.
Extremely fine and faithful reproduction is required.

In a recent electrophotographic image forming apparatus using digital image signals, a latent image is formed by dots of a constant potential gathered on the surface of a latent image carrier, a so-called photosensitive member. The solid portion, the halftone portion, and the line portion are expressed by changing the dot density. However, according to this method, the toner particles hardly adhere to the dots, and the toner particles protrude from the dots, and the gradation of the toner image corresponding to the dot density ratio of the black portion and the white portion of the digital latent image can be obtained. The problem of not being easy to occur. Further, when the resolution is improved by reducing the dot size in order to improve the image quality, the reproducibility of a latent image formed from minute dots becomes more difficult, and the resolution and especially the gradation of the highlight portion are increased. The image tends to be poor in quality and lacks in sharpness.

[0007] As a charging means in such an electrophotographic method, a means utilizing corona discharge called a so-called corotron or scorotron has been used. Therefore, it is necessary to equip the electrophotographic apparatus with a filter for capturing ozone, and there have been problems such as an increase in the size of the apparatus and an increase in running costs. Further, image problems caused by such a corona charging method include, for example, a so-called image flow caused by a decrease in the surface resistance of the photoreceptor due to the attachment of nitrogen oxide or the like, or a problem that the electrophotographic apparatus is stopped. A memory phenomenon of the photoreceptor caused by ions remaining in the charger is exemplified.

As a technique for solving such a problem, a charging member such as a roller or a blade is brought into contact with the surface of a photoreceptor (hereinafter, referred to as direct charging) to form a narrow space near the contact portion. And a discharge method that can be interpreted according to the so-called Paschen's law has been developed to minimize the generation of ozone. For example, JP-A-57-178257 and JP-A-56-1043 have been developed.
No. 51, Japanese Patent Application Laid-Open No. 58-40566, and Japanese Patent Application Laid-Open
This technique is known in Japanese Patent Application Laid-Open Nos. 8-139156 and 58-150975. Among these, a charging method using a charging roller as a charging member is preferably used in terms of charging stability.

The reason why the amount of generated ozone is smaller in direct charging than in corona discharge is considered to be that the charging mechanism on the surface of the photosensitive member is different depending on the discharge area. In corona discharge, it is considered that air molecules are ionized in the discharge area and control the charging of the photoreceptor surface as ions, whereas in direct charging, a large number of electrons are multiplied by electrons in the discharge area. It is charged by reaching the surface.

However, it has been found that there is another problem to be solved in direct charging in addition to the above-mentioned problem in the corona charging method.

Specifically, since direct charging is performed by discharging from a charging member to a member to be charged such as a photoreceptor, it is necessary to apply a voltage higher than a certain threshold voltage in order to start charging. Is mentioned. For example, if the thickness of the photosensitive layer is 2
When a charging roller is brought into contact with a 5 μm OPC photoconductor, the surface potential of the photoconductor starts to increase when a voltage of about 640 V or more is applied, and thereafter, the slope is 1 with respect to the applied voltage. The surface potential of the photoconductor increases. Hereinafter, this threshold voltage is defined as a charging start voltage Vth. That is, in order to obtain the photoconductor surface potential Vd, the charging roller needs to have Vd + V
This requires a DC voltage higher than the required th.
Further, since the resistance value of the contact charging member fluctuates due to environmental fluctuations or the like, it has been difficult to set the potential of the photoconductor to a desired value.

Therefore, in order to further uniform the charging, an AC charging in which an AC component having a peak-to-peak voltage of 2 × Vth or more is superimposed on a DC voltage corresponding to a desired Vd is applied to the contact charging member. The method is disclosed in JP-A-63-14966.
No. 9 discloses this. This is for the purpose of the potential smoothing effect of the AC, and the potential of the charged body converges to Vd, which is the center of the peak of the AC voltage, so that the influence from disturbances such as the environment can be considerably suppressed. Becomes

However, even in such a contact charging device, the essential charging mechanism uses a discharging phenomenon from the charging member to the photosensitive member, so that the voltage required for charging as described above is used. Requires a value equal to or higher than the photoconductor surface potential. When AC charging is performed for uniform charging, vibration and noise (hereinafter referred to as AC charging noise) of the charging member and the photoconductor due to the electric field of the AC voltage are generated.
Deterioration of the photoreceptor surface due to discharge becomes remarkable due to the superposition of the C voltage, and this is a new problem.

[0014] In addition, in order to reduce the generation of ozone, it is originally preferable to perform charging by applying only a DC voltage. However, charging using only DC is susceptible to the effects of environmental fluctuations as described above. In addition, there is a drawback that when the charging member is contaminated, charging unevenness easily occurs.

On the other hand, when the toner image formed on the photosensitive member in the developing step is transferred to the transfer material in the transferring step, if the transfer residual toner remains on the photosensitive member as described above, it is cleaned in the cleaning step. Need to be stored in a waste toner container. For this cleaning process, conventional blade cleaning, fur brush cleaning,
Roller cleaning and the like have been used. In either method, the toner remaining after transfer is mechanically scraped off or dammed and collected in a waste toner container. Therefore, there is an unavoidable problem caused by such a member being pressed against the surface of the photoreceptor. For example, pressing the member strongly wears the photoconductor and shortens the life of the photoconductor. From the viewpoint of the apparatus, the provision of such a cleaning apparatus inevitably increases the size of the apparatus, which has been a bottleneck when aiming for a more compact apparatus. Further, from the viewpoint of ecology, there is a demand for a system that does not generate waste toner in terms of effective utilization of toner.

Here, Japanese Patent Application Laid-Open Nos. Sho 59-133573, Sho 62-203182, and Sho 63-1 disclose techniques related to cleanerless.
No. 33179, JP-A-64-20587, JP-A-2-302772, JP-A-5-2289, JP-A-5-53482, JP-A-5-6138
There is a publication No. 3 which does not mention a desirable toner configuration.

Further, in the simultaneous development cleaning structure having no cleaning device, the transfer residual toner passes between the charging member and the photosensitive member as it is, so that the charging member is easily contaminated, and the resistance of the charging member is not uniform. In the halftone image area, uneven charging which causes extreme uneven density is likely to occur. In addition, in this configuration, it is essential to rub the surface of the photoreceptor with the toner and the toner carrier. However, when the transfer residual toner amount is large, it is necessary to rub more strongly. For this reason, toner deterioration, toner carrier surface deterioration, photoreceptor surface deterioration or abrasion due to long-term use are caused, deterioration of durability characteristics remains as a problem, and it cannot be said that the conventional technology has sufficiently solved the problem. Was.

Japanese Unexamined Patent Publication (Kokai) No. 3-259161 proposes a non-magnetic one-component developer in which a shape factor, a specific surface area, and a particle diameter are specified. Had insufficient non-staining properties and durability.

Japanese Patent Application Laid-Open No. 61-279864 proposes a toner in which the shape factors SF-1 and SF-2 are specified. However, this publication has no description about transfer, and as a result of additional tests of the examples, transfer efficiency and non-staining property of the charging member cannot be said to be sufficient, and further improvement is required.

Further, Japanese Patent Application Laid-Open No. 63-235953 proposes a magnetic toner which is made spherical by mechanical impact. However, the transfer efficiency is still insufficient, and further improvement is required together with the non-staining property of the charging member.

On the other hand, for example, Japanese Patent Laid-Open No.
In Japanese Patent Publication No. 0, there is also proposed a means for improving transferability by mixing an additive such as silica with a non-magnetic one-component toner. However, there is no mention of transferability of the additive itself or charging means of the photoconductor.
Additives having a small particle size used as a transferability improver for toner generally have low transferability and tend to remain on the photoreceptor after transfer. The remaining additive has a small particle diameter and easily slips through the cleaning member. In the case of direct charging, the remaining additive adheres to the charging member and causes poor charging. At this time, if the charging polarity of the additive becomes the same as that of the charging member due to the application of a voltage from the charging member, the additive repels the charging member, is discharged onto the photoconductor, and is collected in the developing device at the developing site. Will be possible,
A high-resistance transfer enhancer such as silica is unlikely to cause polarity reversal and tends to remain firmly attached to the charging member.

Therefore, it is desired to develop a transfer improver which improves the transferability of the toner and is well suited to a direct charging system in which the polarity is easily inverted by an electric field.

On the other hand, toners based on the suspension polymerization method have been proposed for a long time (for example, Japanese Patent Publication No. 36-10231). In this suspension polymerization method, a polymerizable monomer and a colorant (and, if necessary, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives) are uniformly dissolved or dispersed to prepare a monomer composition. After that, this monomer composition is dispersed in a continuous layer (for example, an aqueous phase) containing a dispersion stabilizer using a suitable stirrer, and simultaneously undergoes a polymerization reaction, thereby obtaining toner particles having a desired particle size. Is what you get. The toner obtained by the suspension polymerization method has a high transferability because the individual toner shapes are substantially spherical and the distribution of the charge amount is relatively uniform.

Japanese Patent Application Laid-Open No. Hei 8-305074 describes a cleanerless image forming method using a toner of a specific shape having a residual monomer of 1000 ppm or less. Was sought.

[0025]

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

That is, an object of the present invention is to provide a toner and an image forming method which are excellent in developability and which can maintain a high-resolution image even when outputting a large number of copy images or printer images, and which has excellent durability. is there.

Further, the object of the present invention is to provide excellent transferability, a small amount of untransferred toner, and even without a cleaning device.
An object of the present invention is to provide a toner and an image forming method capable of obtaining a stable image for a long period without causing poor charging.

It is a further object of the present invention to provide a toner and an image forming method capable of preventing toner deterioration and contamination of a charging member for a long period of time without impairing fixability.

[0029]

According to the present invention, there is provided a toner having at least toner particles containing a binder resin and a colorant and fine particles of an inorganic compound, wherein the inorganic compound comprises at least a phosphoric acid compound. And a toner characterized in that:

The present invention also provides a charging step for charging the electrostatic image carrier, an exposure step for forming an electrostatic latent image on the electrostatic image carrier by irradiation of light energy, An image forming method comprising: a developing step of developing an electrostatic latent image on a body and a toner thin-coated on a toner carrier while contacting the toner image; and a transfer step of transferring the toner image to a transfer material. The present invention also relates to a method for forming a contact-developed image using the toner described above.

In the present invention, the cation component constituting the inorganic compound preferably contains at least an ion of a metal selected from alkaline earth metals. Also contains ions of the selected metal, particularly preferably, the inorganic compound is a poorly water-soluble fine particles mainly composed of a phosphate of an alkaline earth metal, and a part of the alkaline earth metal,
By being replaced with a metal selected from the group IB and group VIII metal elements, the transferability of the toner is improved,
On the other hand, even if an inorganic compound that easily remains as a transfer residue passes through the cleaning process and adheres to the charging member, the charge polarity is discharged from the charging member as the same polarity as the charging member due to injection of charge from the charging member, resulting in poor charging and poor charging. The occurrence of uneven charging is prevented. This effect is particularly effective in the configuration of development and cleaning.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have selected various additives which can improve the transferability of a toner, and designed the material so that the charging polarity is easily reversed by applying a voltage. It has been found that the object can be achieved by incorporating a metal ion selected from Group IB and Group VIII metal elements therein. In particular, when these metal ions were contained in the vicinity of the surface of the inorganic compound fine particles by an ion exchange method or the like, the effect was remarkable.

The Group IB and Group VIII metals tend to be in either a neutral state or a cationic state. Therefore, if the fine particles are present in the cationic state on the surface, the fine particles can be charged to a positive polarity, and if the fine particles are present in the neutral state, the fine particles become negative due to the influence of phosphate ions. Charges. That is, it is possible to charge the fine particles to either positive or negative polarity according to the applied voltage.

The group IB and group VIII metal ions
Among them, Fe, Pd, Pt, Ag, and Au ions are more preferable.
Best, Ag Ions are particularly preferred. This is Ag⁰⇔ Ag⁺⇔ Ag²⁺ The ionization potential of each process indicated by is relatively low
Therefore, Ag existing on the surface of the fine particles⁺Responds to the applied voltage.
Ag²⁺(Positive charge state) or Ag⁰(Negative charge
State). However, this
These IB and VIII metal compounds themselves have resistance.
Charge polarity of toner deteriorates when used as is
Or a leak may occur between the developer carrier and
Since the image is disturbed, as in the present invention, a transferability improver
Must be used as part of the composition of In addition, transferability
Excessive Group IB and VIII metal ions inside the enhancer
Is present, the surface charge moves inward,
The part also becomes charged, but when this happens, external voltage
Even if the voltage is applied, the polarity inversion hardly occurs immediately,
More preferably, the Group IB and Group VIII metal ions are converted.
It is preferable to use it in the vicinity of the surface of the photosensitizer.

In order to obtain excellent environmental characteristics, it is preferable that the inorganic compound serving as a base is poorly water-soluble. In addition, the metal ions constituting the inorganic fine particles are composed of IB group and VI
As a result of exploring various materials whose ionic radius is close to that of Group II metals and ion exchange easily occurs, and whose resistance characteristics are stable even when voltage is applied for a long time after cation exchange, alkaline earth was found to be the main component of the cation. An inorganic compound composed of an ion of a metal selected from metals is preferable. Further, the following formula (1): M ₁₀ X _m (PO ₄ ) _n (1) (where M is an alkaline earth metal, and X is an anion And m and n represent coefficients satisfying 0.5 ≦ m ≦ 5 and 5 ≦ n ≦ 7, where m and n represent the ratios of X and phosphate groups to metal M.) It has been found that by selecting inorganic fine particles having a composition, group IB and group VIII metal ions can be stably present near the surface by ion exchange, electroless plating, or the like. Here, more preferable alkaline earth metals include Mg, Ca, Sr, and Ba.
More preferred anions include hydroxyl ion, nitrate ion, carbonate ion and halogen ion. In addition, as the alkaline earth metal constituting the inorganic fine particles, 1
Species or a mixture of two or more can be used. Further, it is preferable that the inorganic fine particles have an apatite structure.

That is, the toner according to the present invention uses poorly water-soluble inorganic compound fine particles having excellent environmental properties as a transferability improver, and the inorganic compound fine particles (particularly in the vicinity of the surface) are used.
By making some IB and VIII metal ions,
Even if the fine particles remaining after transfer adhere to the charging member, the charging polarity becomes the same as that of the charging member easily by applying a voltage, and the particles are quickly discharged from the charging member to prevent poor charging, thereby giving rise to the idea.

In addition, the resistance of the inorganic compound is 10 ⁴ to
By controlling and using the toner in the range of 10 ¹² Ω · cm, the electrophotographic characteristics of the toner and the chargeability of the photoconductor are further improved. When the resistance is lower than 10 ⁴ Ω · cm, the triboelectric charging characteristic of the toner tends to decrease under high humidity, and when the resistance is higher than 10 ¹² Ω · cm, the polarity reversal of the inorganic compound hardly occurs. At the same time, the tribo of the toner tends to be too high during durability under low humidity.

The preferred average particle size of the inorganic compound according to the present invention is 0.05 to 2 μm. If the thickness is less than 0.05 μm, the effect as a transferability improving agent based on the spacer effect will be poor, and the discharging property from the charging member will be reduced, so that poor charging tends to occur. If it is larger than 2 μm, it is easy to be released from the toner surface, so that the effect as a transferability improver is also poor, and the effective number of inorganic compounds decreases, so that it is necessary to increase the amount of addition to the toner. As a result, toner characteristics such as fixability and fluidity deteriorate.

These inorganic compounds are used in a mixing ratio of 0.02 to 2.5 parts by weight with respect to 100 parts by weight of the toner particles. When the amount is less than 0.02 parts by weight, the effect of improving the transferability of the toner is poor, and when the amount exceeds 2.5 parts by weight, the chargeability and the fixability of the toner are likely to be adversely affected.

These inorganic compounds may be used after being subjected to a surface treatment with various surface treatment agents in order to adjust the triboelectric charge amount of the toner or to further improve the environmental characteristics. The treatment method can be arbitrarily selected, such as a wet method in a solution or a dry method.

The durability of the toner particles according to the present invention is further improved when the value of the shape factor SF-1 measured by an image analyzer satisfies the following expression. 100 <SF-1 ≦ 160, preferably 100 <SF-1 ≦ 140, and more preferably 100 <SF-1 ≦ 120.

Further, the transferability of the toner particles according to the present invention is further improved when the value of the shape factor SF-2 measured by the image analyzer satisfies the following expression. 100 <SF-2 ≦ 140, preferably 100 <SF-2 ≦ 130, and even more preferably 100 <SF-2 ≦ 120.

Here, in the present invention, SF-1 and SF-2 indicating the shape factor are, for example, FE-S manufactured by Hitachi, Ltd.
2 μm expanded 1000 times using EM (S-800)
The above-mentioned 100 toner images are randomly sampled, and the image information is introduced into, for example, an image analyzer (Luzex III) manufactured by Nicole via an interface, analyzed, and calculated by the following equation. Is the shape factor SF−
1, SF-2.

[0044]

(Equation 1)

Where MXLNG is the absolute maximum length of the particle,
PERI indicates the perimeter of the particle, and AREA indicates the projected area of the particle. ]

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

By controlling these shape factors,
It is possible to improve not only contamination of the surface of the charging member in image formation on a large number of sheets but also fusion of the toner on the toner carrier, thereby further improving durability.

In the case of 160 <SF-1, the toner is separated from the spherical shape and approaches an irregular shape, the toner is easily crushed in the developing device, the particle size distribution is fluctuated, and the charge amount distribution is easily broadened, and the photosensitive member is formed on the photosensitive member. The development of the toner on the non-image portion, that is, so-called fogging is likely to occur. Further, transfer residual toner also increases, and when these adhere to the charging member, the contact area is large, so that the discharging property from the charging member due to an electric field or the like is reduced, which causes charging unevenness.

In the case of 140 <SF-2, the transfer efficiency of the toner from the photoreceptor to the transfer material such as paper is reduced. In particular, in the cleanerless configuration, the contamination of the charging member by the transfer residual toner is promoted. Therefore, the charging property is deteriorated, which is not preferable.

The toner particles according to the present invention, particularly when having a weight average particle diameter of 1 to 9 μm, make it possible to stably obtain a very high-quality image for a long period of time.

It is generally known that when the particle size of the toner is small, the resolution at the time of development is improved. However, in addition to the increase in the surface area of the entire toner, the fluidity and agitation of the toner powder are reduced. However, it is difficult to uniformly charge the individual particles. For example, toner particles having an extremely high charge amount may be generated.

However, by regulating the SF-1 and SF-2 of the toner particles as described in the present invention, individual particles can be uniformly charged even if the toner has a small particle size. In addition, when the inorganic compound according to the present invention and the toner particles having a high charge amount come into contact with each other, the inorganic compound receives an excessive charge of the toner, and the charge amount of the toner is excessively relaxed, so that the charge amount becomes uniform, and Fine images can be obtained over a long period of time.

The toner of the present invention has a softening point of 40 to 90 ° C.
It is also one of the preferred usage forms to contain wax.

As described above, a very high-quality image can be obtained by using a toner having a weight-average particle size of 9 μm or less. Into the gaps of the paper fibers, the heat from the heat fixing roller is insufficiently received, and low-temperature offset is likely to occur. However, by incorporating wax as a release agent in the toner of the present invention, it is possible to prevent charging unevenness while achieving both high resolution and offset resistance.

Here, the softening point of the wax used is 4
It is important that the temperature is 0 to 90 ° C. When the softening point is less than 40 ° C., the blocking resistance and the shape retention of the toner are insufficient. On the other hand, when the softening point is more than 90 ° C., the effect of the releasability becomes insufficient, and the fixability is impaired. Here, as the softening point of the wax, a value according to the ring and ball method (JIS K 2531) is adopted.

The waxes used in the present invention include:
Examples include paraffin / polyolefin waxes, ester waxes, and modified products thereof, for example, oxides and grafted products, higher fatty acids, metal salts thereof, and amide waxes. These may be used as a mixture of two or more. The content at that time is preferably in the range of 0.1 to 50% by weight based on the whole toner. If the content is less than 0.1% by weight, the effect of suppressing low-temperature offset is poor, and if it exceeds 50% by weight, the long-term storability is deteriorated, the dispersibility of other toner materials is deteriorated, and the fluidity of the toner is lowered. This leads to deterioration and deterioration of image characteristics.

JP-A-5-281779 discloses a toner containing a magnetic material whose surface is coated with a metal compound, and JP-A-6-138797 discloses the addition of an inorganic compound powder to improve thermal characteristics and thermal properties. Japanese Patent Application Laid-Open No. Hei 7-92718 discloses a toner having improved environmental characteristics, and further discloses an electrophotographic method using a developer containing a metal or an oxide thereof. The difference will be described.

The metal compound disclosed in JP-A-5-281779 uniformly coats the surface of a magnetic material by electroless plating, and the coated magnetic material is used by being incorporated in a toner. The invention is to adjust the tint of the toner by incorporating the colored magnetic material into the toner. Therefore, the concept is completely different from the concept of the present invention in which an inorganic compound is externally added to the toner surface to prevent the charging member from being contaminated.

Further, in the specification of the inorganic compound powder disclosed in Japanese Patent Application Laid-Open No. 6-138697, there is no description in the specification that the anion contained in the composition may be a phosphate-based anion. This is clearly different from the inorganic compound of the present invention which contains a phosphate anion as an essential component. Here, according to the study of the present inventors,
Rate of reversal of polarity of inorganic compound by charge injection from charging member, and part IB group and VI of inorganic compound composition
It has been found that the presence of a phosphate-based anion has a large effect on the ease of conversion to group II metal ions. Further, the inorganic compound powder disclosed in Japanese Patent Application Laid-Open No. 6-138697 is used for the purpose of improving the thermal characteristics and environmental characteristics of a toner, and prevents poor charging by discharging from a charging member. This invention differs from the present invention not only in the composition but also in the purpose of use.

Further, as can be seen from the examples, the metal compound disclosed in JP-A-7-92718 is internally added to the toner composition to obtain a wiring circuit while imparting conductivity to the developer. The present invention is completely different from the present invention in that the charging member is prevented from being contaminated by an inorganic compound externally added to the toner while maintaining the insulating property of the toner.

The binder resin that can be used in the toner of the present invention includes:
All known ones can be used.

For example, a colorant or a charge control agent composed of a dye or pigment is melt-mixed in a thermoplastic resin and uniformly dispersed, and then a toner having a desired particle size is produced by a fine pulverizer and a classifier. In the method, so-called pulverization method, polystyrene, poly-P-chlorostyrene, a homopolymer of styrene such as polyvinyltoluene and a substituted product thereof, a styrene-P-chlorostyrene copolymer, a styrene-propylene copolymer, a styrene-vinyl Toluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-
Octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer Polymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer Styrene-based copolymers such as polymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, and polystyrene Le, polyurethane, polyamide,
Epoxy resin, polyvinyl butyral, polyamide,
Polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin,
Aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be used alone or as a mixture.

On the other hand, in the toner production method by the polymerization method, for example, styrene, o (m
-, P-)-methylstyrene, m (p-)-ethylstyrene and other styrene monomers; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) acryl Butyl acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate,
(Meth) acrylate monomers such as 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylic Monomers such as acid amides are preferably used. These can be used alone or generally in the published Polymer Handbook, 2nd edition-P139-192.
The monomers are appropriately mixed and used so that the theoretical glass transition temperature (Tg) described in (John Wiley & Sons) shows 40 to 75 ° C. Theoretical glass transition temperature is 4
If the temperature is lower than 0 ° C., problems occur in terms of the storage stability of the toner and the durability stability of the developer. On the other hand, if the temperature is higher than 75 ° C., the fixing point is increased. And the color reproducibility is poor, and the transparency of the OHP image is significantly reduced, which is not preferable from the viewpoint of high image quality. At this time, if a monomer having two or more polymerizable functional groups in one molecule, such as divinylbenzene, is contained, an appropriate network is formed in the toner, and the fixing property and the durability are further improved. It becomes possible.

Known methods are used for producing the toner according to the present invention. For example, a binder resin, a wax, a metal salt or a metal complex, a pigment as a colorant, a dye, or a magnetic substance, and if necessary, The charge control agent and other additives are thoroughly mixed by a mixer such as a Henschel mixer or a ball mill, and then melt-kneaded using a heat kneader such as a heating roll, kneader or extruder to make the resins compatible with each other. A metal compound, a pigment, a dye, and a magnetic substance are dispersed or dissolved in the mixture, and after cooling and solidifying, pulverization and classification are performed to obtain a developer according to the present invention. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency. If necessary, the surface may be modified before and after the classification step.

In the present invention, when a toner is produced by a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and the water phase migration property of the colorant.
It is better to perform a hydrophobic treatment with a substance that does not inhibit polymerization. As a preferable method for surface-treating the dye system, there is a method in which a polymerizable monomer is polymerized in the presence of these dyes in advance, and the obtained colored polymer is added to the monomer system.

Examples of the polymerization initiator used for polymerization in an aqueous medium in the present invention include, for example, 2,2′-azobis-
(2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2, Azo polymerization initiators such as 4-dimethylvaleronitrile and azobisisobutyronitrile; peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and lauroyl peroxide; A polymerization initiator is used.

The amount of the polymerization initiator to be added varies depending on the desired degree of polymerization, but generally ranges from 0.5 to 2 with respect to the monomer.
0% by weight is used. Although the type of the initiator slightly varies depending on the polymerization method, it is used alone or in combination with reference to the 10-hour half-life temperature.

In order to control the degree of polymerization, known crosslinking agents, chain transfer agents, polymerization inhibitors and the like can be further added and used.

In the present invention, as a dispersant used in the case of conducting polymerization in an aqueous medium, for example, inorganic compounds such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, Calcium hydroxide, magnesium hydroxide,
Examples include aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic material, and ferrite. As the organic compound, for example, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, starch and the like are used by being dispersed in an aqueous phase. It is preferable to use 0.2 to 10 parts by weight of these dispersants based on 100 parts by weight of the polymerizable monomer.

As these dispersants, commercially available ones may be used as they are, but in order to obtain finely dispersed particles having a uniform particle size, it is necessary to form the inorganic compound under high-speed stirring in a dispersion medium. You can also. For example, in the case of tricalcium phosphate, a dispersant suitable for a suspension polymerization method can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring. Further, 0.001 to 0.1% by weight of a surfactant may be used in combination for making these dispersants finer. Specifically, commercially available nonionic, anionic, and cationic surfactants can be used. For example, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate , Potassium stearate, calcium oleate and the like are preferably used.

When the toner of the present invention is produced by a polymerization method, it is possible to specifically produce the toner by the following method. A colorant, charge control agent, polymerization initiator, and other additives are added to the monomer, and the monomer composition is uniformly dissolved or dispersed by a homogenizer, an ultrasonic disperser, etc., and a dispersion stabilizer is contained. In an aqueous phase to be dispersed using a conventional stirrer, homomixer, homogenizer or the like. Preferably, the stirring speed and time are adjusted so that the droplets of the monomer composition have the desired size of the toner particles, and the granulation is performed. Thereafter, by the action of the dispersion stabilizer, the particles may be stirred to such an extent that the particle state is maintained and the particles are prevented from settling. The polymerization is performed at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. Further, the temperature may be raised in the second half of the polymerization reaction, and further, for the purpose of improving the durability characteristics in the image forming method of the present invention, the second half of the reaction for removing unreacted polymerizable monomers, by-products, and the like, Alternatively, a part of the aqueous medium may be distilled off after the completion of the reaction. After the reaction, the generated toner particles are collected by washing and filtration, and dried. In this method, the monomer system 10
It is preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 0 parts by weight.

In the present invention, it is desirable to add a charge control agent to the toner material in order to control the chargeability of the toner. These charge control agents include, for example, triphenylmethane dyes, quaternary ammonium salts, guanidine derivatives, imidazole derivatives, amine-based and polyamine-based compounds as positive charge control agents. Examples include metal salts or metal complexes of carboxylic acid derivatives, urea derivatives, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, metal salts or metal complexes of azo dyes or azo pigments. The addition amount of these charge control agents is 0.1 to 10% by weight.
Is preferred.

The toner of the present invention may be used by further adding a fluidity improver. The fluidity improver is not particularly limited as long as it can improve fluidity after being added to the toner particles. For example, silica fine powder, titanium oxide fine powder, alumina fine powder, or those obtained by subjecting their surfaces to a hydrophobic treatment can be used alone or in combination of two or more.

The toner of the present invention may be used as a one-component developer, or may be used as a two-component developer in combination with a carrier. Examples of the carrier include conventionally known carriers such as iron powder, magnetite powder, ferrite powder, glass beads, and magnetic powder dispersed in a resin. These carriers may be coated on the surface with a resin or the like as necessary. Examples of the resin used in this case include a fluorine-containing resin, a phenol resin, a styrene resin, an acrylic resin, and a styrene-acryl copolymer. , Silicone resin and the like. These coating resins may be used alone or in combination of two or more. When the mixing ratio of the toner and the carrier is 1 to 15% by weight, preferably 2 to 13% by weight as the toner concentration in the developer, usually good results can be obtained.

The toner of the present invention is particularly effective when the charging means is a direct charging method in which a charging member is brought into contact with a photosensitive member. That is, in the case of a general toner, if the transfer residual toner mixture that has passed through the cleaning process adheres to the charging member in the subsequent process, poor charging is caused, and charging unevenness occurs on an image. Therefore, compared to corona discharge or the like in which the charging means does not contact the photoconductor, the amount of the remaining toner mixture is
It is necessary to reduce the amount of adhesion to a minimum, making it difficult to adhere, and even if it adheres, the amount of adhesion is reduced as much as possible by spitting. Therefore, in the direct charging method, it can be said that the toner of the present invention containing the inorganic compound fine particles having a good discharging property while improving the transferability of the toner is suitable.

The preferable conditions of the developing step used in the present invention are that the developer and the surface of the photoreceptor are in contact with each other and that the reversal developing method is used. At this time, at the time of development or at the time of blank before and after development, a DC or AC component bias is applied to control the potential so that the development and the remaining toner mixture on the photoreceptor can be recovered. At this time, the DC component is located between the light portion potential and the dark portion potential.

In the case of a one-component developer, a method is also used in which an elastic roller is used as a toner carrier, the surface of the elastic roller is coated with toner, and this is brought into contact with the surface of the photoreceptor. At this time, it is important that the toner is in contact with the surface of the photoconductor. In this case, cleaning is performed simultaneously with development by an electric field acting between the photoconductor and the elastic roller facing the photoconductor surface via the toner. Therefore, the surface of the elastic roller or the vicinity of the surface has a potential, and the surface of the photoconductor and the toner are cleaned. There is a need to have an electric field in the narrow gap of the carrying surface.
For this reason, the elastic rubber of the elastic roller is resistance-controlled in the medium resistance region, and maintains the electric field while preventing conduction with the photoconductor surface,
Alternatively, a method of providing a thin insulating layer on the surface layer of the conductive roller can also be used. Further, it is also possible to adopt a configuration in which a conductive layer is provided on a conductive roller on a conductive roller on which the side facing the photoreceptor surface is covered with an insulating material, or on a side not facing the photoreceptor with an insulating sleeve. It is also possible to employ a configuration in which a rigid roller is used as the toner carrier and the photosensitive member is a flexible member such as a belt. The resistance of the developing roller as a toner carrier is 10 ² to 10 ⁹ Ω.
-The range of cm is preferable.

When the one-component contact developing method is used, the peripheral speed of the surface of the roller carrying the toner and the photosensitive member may be rotated in the same direction or in the opposite direction. When the rotation is in the same direction, the peripheral speed ratio is preferably 100% or more with respect to the peripheral speed of the photoconductor. If it is less than 100%, the image quality tends to be poor. The higher the peripheral speed ratio, the greater the amount of toner supplied to the development site, the more frequently the toner is attached to and detached from the latent image, and unnecessary portions are scraped off and added to necessary portions repeatedly. As a result, an image faithful to the latent image can be obtained. From the viewpoint of cleaning at the same time as the development, it is expected that the residual toner adhered to the photoreceptor is physically separated from the surface of the photoreceptor by a difference in peripheral speed and recovered by an electric field. The higher the ratio, the more convenient it is to collect the transfer residual toner.

One preferred configuration of the image forming method according to the present invention will be specifically described with reference to FIG.

In FIG. 1, reference numeral 100 denotes a developing device;
Is a photoreceptor, 105 is a transfer target such as paper, 106 is a transfer member, 107 is a fixing pressure roller, 108 is a fixing heating roller, and 110 is a primary charging member that contacts the photoreceptor 109 and performs direct charging. Show.

A bias power supply 115 is connected to the primary charging member 110 so as to uniformly charge the surface of the photoconductor 109.

The developing device 100 contains a toner 104, and includes a toner carrier 102 which rotates in the direction of the arrow in contact with the photosensitive member 109. Further, a developing blade 101 for regulating a toner amount and applying a charge, and a toner 104
To the toner carrier 102 and the toner carrier 10
An application roller 103 that rotates in the direction of the arrow to apply charge to the toner by friction with the roller 2 is also provided. A developing bias power supply 117 is connected to the toner carrier 102.
A bias power supply 118 is also connected to the application roller 103, and a voltage is set to a negative side of the developing bias when using a negatively charged toner, and to a positive side than the developing bias when using a positively charged toner. Is done.

The transfer member 106 is connected to a transfer bias power supply 116 having a polarity opposite to that of the photosensitive member 109.

Here, the photosensitive member 109 and the toner carrier 10
The length of the contact portion 2 in the rotational direction, that is, the so-called development nip width is preferably 0.2 mm or more and 8.0 mm or less.
If the thickness is less than 0.2 mm, a sufficient image density cannot be obtained due to a shortage of the supplied amount of toner, and the transfer residual toner is insufficiently collected. If the thickness exceeds 8.0 mm, the toner supply amount becomes excessive, fog suppression is likely to be deteriorated, and abrasion of the photoconductor is adversely affected.

As the toner carrier, a so-called elastic roller having an elastic layer on its surface is preferably used. The hardness of the material of the elastic layer used is 20 to 65 degrees (J
ISA) are preferably used.

The resistance of the toner carrier is preferably in the range of about 10 ³ to 10 ⁹ Ωcm in terms of volume resistance. 1
If it is lower than 0 ³ Ωcm, for example, if there is a pinhole on the surface of the photoreceptor, an overcurrent may flow. On the other hand, when it is higher than 10 ⁹ Ωcm, the toner is liable to be charged up due to frictional charging, and the image density is liable to be reduced.

The amount of toner coating on the toner carrier is 0.1
It is preferably from 1 mg / cm ^{2 to} 1.5 mg / cm ² .
If it is less than 0.1 mg / cm ^2, it is difficult to obtain a sufficient image density, and if it is more than 1.5 mg / cm ^2, it becomes difficult to uniformly tribocharge all the individual toner particles,
It becomes a factor of deterioration of fog control. In addition, 0.2 mg /
It is more preferably not less than cm ^{2 and not} more than 0.9 mg / cm ² .

The toner coating amount is controlled by a developing blade 101, which is in contact with a toner carrier 102 via a toner layer. The contact pressure at this time is preferably in the range of 5 g / cm to 50 g / cm. If it is less than 5 g / cm, uniform triboelectric charging becomes difficult in addition to control of the amount of toner coating, which causes deterioration of fog suppression and the like. On the other hand, if it is larger than 50 g / cm, the toner particles are subjected to an excessive load, so that deformation of the particles and fusion of the toner to the developing blade or the toner carrier are liable to occur, which is not preferable.

In FIG. 1, the primary charging member 110 uniformly charges the photosensitive member 109 rotating in the direction of the arrow. Then, an electrostatic latent image corresponding to the information signal is formed on the photoconductor 109 by exposure 111 from the light emitting element, and the toner carrier 1
The electrostatic latent image is developed with toner at a position where the electrostatic latent image comes into contact with the image No. 02 and is visualized. Next, the visible image is transferred onto the transfer object 105 by the transfer member 106, and further the transfer toner 112 is transferred.
Is fixed by passing between the heating roller 108 and the pressure roller 107 together with the transfer target 105 to obtain a permanent image.

At this time, the transfer residual toner 113 remaining on the photosensitive member 109 without being transferred passes between the photosensitive member 109 and the primary charging member 110 and reaches the developing nip again.
The toner is collected in the developing device 100 by the toner carrier 102.

Next, various measuring methods in the present invention will be described.

(1) Resistance of Inorganic Compound The resistance of the inorganic compound was measured using the cell shown in FIG. That is, the cell A is filled with the measurement sample, the electrodes 21 and 22 are arranged so as to be in contact with the filled sample 27, and a DC voltage is applied between the electrodes by the power supply 26 while a load of 15 kg is applied to the upper electrode 22. The current flowing at that time was measured by a DC ammeter 24. In the measurement, assuming that the contact area (= electrode area) of the filled sample with the cell is S, the thickness of the sample (= distance between electrodes) is d, the applied voltage is V, and the flowing current value is I, the resistance of the sample is resistance ( Ω · cm) = (V / I) × (S / d)

In the present invention, as typical measurement conditions, S = 2.3 cm ² , thickness d = 0.2 cm, V = 10
00V was adopted.

(2) Average Particle Size of Inorganic Compound The average particle size of the inorganic compound was measured using a transmission electron microscope. That is, the measured powder sample was observed with a transmission electron microscope, and the particle diameter of 100 particles in the visual field was measured to determine the average particle diameter.

(3) Average Particle Size and Particle Size Distribution of Toner Particles The average particle size and particle size distribution of the toner particles are determined by using a Coulter Counter TA-II or a Coulter Multisizer (manufactured by Coulter, Inc.). Output interface (made by Nikkaki) and PC9801
A personal computer (manufactured by NEC) is connected, and a 1% NaCl aqueous solution is prepared as an electrolytic solution using primary sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 100 to 150 m of the electrolytic aqueous solution is used.
0.1 to 5 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersing agent in 1 l, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the volume and number of toner particles having a size of 2 μm or more were measured by using the Coulter Counter TA-II with an aperture of 100 μm. To calculate the volume distribution and the number distribution. Then, a volume-based weight average particle diameter (D ₄ ) determined from the volume distribution according to the present invention was determined.

(4) Method of Measuring Friction Charge Amount FIG. 3 is an explanatory view of an apparatus for measuring the charge amount of toner.
First, about 0.5 to 1.0 g of a mixture (developer) of a toner and a carrier whose frictional charge is to be measured is placed in a metal measuring container 32 having a 500-mesh screen 33 at the bottom. Do 34. Measurement container 3 at this time
2 The total weight is weighed to be W1 (kg). Next, the suction device 31 (the part in contact with the measurement container 32 is at least an insulator)
In, the pressure of the vacuum gauge 35 is adjusted to 2450 Pa (250 mmAq) by adjusting the amount of air sucked from the suction port 36.
In this state, suction is performed sufficiently, preferably for about 2 minutes to remove the toner by suction. At this time, the potential of the electrometer 38 is set to V (volt). Here, 37 is a capacitor whose capacity is C (mF). Further, the weight of the whole measurement container after suction is weighed to be W2 (kg). At this time, the triboelectric charge amount (mC / kg) of the toner is calculated by the following equation. Amount of triboelectric charge of toner (mC / kg) = (C × V) / (W
1-W2)

(5) Method of Measuring Fog of Fixed Image Fog was measured by REFLECTMET manufactured by Tokyo Denshoku Co., Ltd.
Measured using ER MODEL TC-6DS.
The filter was a green filter and was calculated by the following equation. The smaller the value, the less fog.

Fog (reflectance) (%) = reflectance on standard paper (%) − reflectance of non-image portion of sample (%)

[0099]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

(Production Example 1 of Black Polymerized Toner Particles) To 710 parts by weight of ion-exchanged water in a two-liter four-necked flask,
450 parts by weight of a 0.1 M Na ₃ PO ₄ aqueous solution was added,
After heating to 0 ° C., the mixture was stirred at 12,000 rpm using a high-speed stirrer TK homomixer (manufactured by Tokushu Kika Kogyo). To this, 68 parts by weight of a 1.0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous dispersion medium containing a minute poorly water-soluble dispersant.

On the other hand, 155 parts by weight of styrene (monomer) 45 parts by weight of n-butyl acrylate (colorant) 10 parts by weight of carbon black (charge control agent) 4 parts by weight of a compound of a monoazo dye and Fe (release agent) 20 parts by weight of ester wax (softening point: 75 ° C.) Among the above-mentioned formulations, only a colorant, an Fe compound of a monoazo dye and styrene were used to produce a master batch of carbon black using an attritor (manufactured by Mitsui Kinzoku Co., Ltd.). Next, this masterbatch and the remaining ingredients of the above formulation were heated to 60 ° C., dissolved and dispersed to obtain a monomer mixture. further,
While maintaining at 60 ° C., 8 parts by weight of an initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was added and dissolved to prepare a monomer composition.

The monomer composition was charged into the aqueous dispersion medium prepared in the 2-liter flask of the homomixer. Using a TK homomixer in a nitrogen atmosphere at 60 ° C., the mixture was stirred at 10,000 rpm for 20 minutes to granulate the monomer composition. Then, while stirring with paddle stirring blades, 60
After reacting at 80 ° C. for 6 hours, polymerization was carried out at 80 ° C. for 10 hours.

After the completion of the polymerization reaction, the reaction product is cooled, hydrochloric acid is added to dissolve the poorly water-soluble dispersant, and the polymer is filtered, washed with water and dried to obtain black polymerized toner particles 1 having a weight average diameter of 7.0 μm. Was. Table 1 shows various physical properties.

(Production Example 2 of Black Polymerized Toner Particles) As a dispersoid (monomer) 160 parts by weight of styrene 40 parts by weight of n-butyl acrylate (colorant) 10 parts by weight of carbon black (charge control agent) Compound of monoazo dye and Fe 4 parts by weight (release agent) Black polymerized toner particles 2 having a weight average diameter of 7.0 µm by the same method as in Production Example 1 of black polymerized toner particles except that 20 parts by weight of a low molecular weight polyethylene wax (softening point 115 ° C) was used.
I got Table 1 shows various physical properties.

(Production Example 3 of Black Polymerized Toner Particles) The same method as in Production Example 1 of black polymerized toner particles except that 100 parts by weight of an ester wax having a softening point of 75.degree. Black polymerized toner particles 3 were obtained. Table 1 shows various physical properties.

(Production Example 4 of Black Polymerized Toner Particles) Black polymerized toner particles 4 having a weight average diameter of 6.9 μm were obtained in the same manner as in Production Example 1 of black polymerized toner particles without using a release agent. Table 1 shows various physical properties.

(Production Example 5 of Black Polymerized Toner Particles) The same materials as in Production Example 1 of Black Polymerized Toner Particles were used, except that the amount of the poorly water-soluble dispersant was adjusted. Black polymerized toner particles 5 having a weight average diameter of 9.2 μm were obtained. Table 1 shows various physical properties.

(Production Example 1 of Black Pulverized Toner Particles) (Resin) 100 parts by weight of styrene-butyl acrylate copolymer (copolymerization ratio: 80:20) (colorant) 5 parts by weight of carbon black (charge control agent) Monoazo dye Compound with Fe 2 parts by weight (mold release agent) 5 parts by weight of low molecular weight polyethylene wax (softening point 115 ° C.) 5 parts by weight The above materials are mixed in advance and 12 parts are extruded with a twin screw extruder.
Melt kneading was performed at 0 ° C. This melt-kneaded material was crushed by a hammer mill to obtain a crushed toner having a 1 mm mesh pass. Further, the coarsely crushed product is finely pulverized by a collision type pulverizer using a jet stream, and then subjected to air classification to obtain a weight average diameter of 9.9.
μm of black ground toner particles 1 were obtained. Table 1 shows various physical properties.

(Production Example 2 of Black Pulverized Toner Particles) Black pulverized toner particles 1 were added to an aqueous solution containing a surfactant, and spheroidized at 75 ° C. for 2 hours while stirring at a high speed, followed by filtration and washing with water. After drying, the weight average diameter was 10.1 μm
To obtain black pulverized toner particles 2. Table 1 shows various physical properties.

[0110]

[Table 1]

(Inorganic Compound Fine Particle Production Example 1) 500 parts by weight of ion-exchanged water in a two-liter four-necked flask was mixed with 95 parts by weight.
While stirring at a high speed at 100 ° C., 100 parts by weight of a 1.0 M Na ₃ PO ₄ aqueous solution and 100 parts by weight of a 0.3 M CaCl ₂ aqueous solution were gradually dropped at the same time, and a white precipitate of poorly water-soluble inorganic compound fine particles was added. I got Next, the precipitate is filtered and washed, added to 500 parts by weight of a 0.1 M AgNO ₃ aqueous solution, stirred at 90 ° C. for 1 hour, filtered, dried, crushed, and ion-exchanged. Inorganic compound fine particles 1 containing Ag ions only near the surface were prepared by the method. Table 2 shows various physical properties of the obtained inorganic compound fine particles 1.

[0112] In (inorganic compound fine particles Production Example 2 and 3) the inorganic compound fine particles Production Example 1, Na ₃ PO ₄ aqueous solution and C
By adjusting the dropping speed of the aCl ₂ aqueous solution, the reaction temperature and the stirring speed, poorly water-soluble inorganic compound fine particles having different particle diameters were obtained. Thereafter, inorganic compound fine particles 2 and 3 containing Ag ions only in the vicinity of the surface were prepared in the same manner as in the inorganic compound fine particle production example 1 except that AgNO ₃ aqueous solutions having different concentrations were used. Table 2 shows properties of the obtained inorganic compound fine particles 2 and 3.

(Example 4 of Production of Fine Inorganic Compound Fine Particles) Except that 500 parts by weight of a 0.05M-Pd (NO ₃ ) ₂ aqueous solution was used instead of 500 parts by weight of a 0.1M AgNO ₃ aqueous solution in Production Example 1 of inorganic compound fine particles. Uses a similar technique,
Inorganic compound fine particles 4 containing Pd ions only in the vicinity of the surface were prepared by an ion exchange method. Table 2 shows properties of the obtained inorganic compound fine particles 4.

(Production Example 5 of Inorganic Compound Fine Particles) A 0.5 M AgNO ₃ aqueous solution 5 was placed in a two-liter four-necked flask.
While stirring at a high speed at 95 ° C.
-Na ₃ PO ₄ aqueous solution (100 parts by weight) and 0.3 M-CaCl
₂ 100 parts by weight of the aqueous solution was gradually dropped at the same time to obtain a precipitate of poorly water-soluble inorganic compound fine particles. The precipitate was separated by filtration, dried and crushed to prepare inorganic compound fine particles 5 containing Ag ions throughout the particles by a coprecipitation method. Table 2 shows properties of the obtained inorganic compound fine particles 5.

(Inorganic Compound Fine Particle Production Example 6) 500 parts by weight of ion-exchanged water in a two-liter four-necked flask was added to 95 parts by weight.
While stirring at a high speed at 100 ° C., 100 parts by weight of a 1.0 M Na ₃ PO ₄ aqueous solution and 100 parts by weight of a 0.3 M CaCl ₂ aqueous solution were gradually dropped at the same time, and a white precipitate of poorly water-soluble inorganic compound fine particles was added. I got The precipitate was separated by filtration, dried, and pulverized to prepare inorganic compound fine particles 6 containing no ions of Group IB and Group VIII metal elements. Table 2 shows properties of the obtained inorganic compound fine particles 6.

(Inorganic Compound Fine Particle Production Example 7) In the inorganic compound fine particle production example 1, a 0.3 M-MgCl ₂ aqueous solution 1 was replaced with 100 parts by weight of a 0.3 M-CaCl ₂ aqueous solution.
Using the same technique except that 00 parts by weight was used, inorganic compound fine particles 7 containing Ag ions only in the vicinity of the surface were prepared by an ion exchange method. Table 2 shows properties of the obtained inorganic compound fine particles 7.

[0117] In (inorganic compound fine particles Production Example 8) the inorganic compound fine particles Production Example 1, in place of the 0.1 M-AgNO ₃ aqueous solution 500 parts by weight, 0.1 M-MnCl ₂ aqueous 5
Using the same method except that 00 parts by weight was used, inorganic compound fine particles 8 containing Mn ions only in the vicinity of the surface were prepared by an ion exchange method. Table 2 shows properties of the obtained inorganic compound fine particles 8.

(Production Example 9 of Inorganic Compound Fine Particles) 500 ml
0.01M-AgNO ₃ aqueous solution 2 in a graduated flask
100 parts by weight of fine particles of calcium carbonate having a particle size of 0.30 μm were added to 00 parts by weight, water was removed by an evaporator, and the mixture was dried and crushed to prepare inorganic compound fine particles 9 carrying Ag ions on the surface. Obtained inorganic compound fine particles 9
Are shown in Table 2.

(Inorganic Compound Fine Particle Production Example 10) In the inorganic compound fine particle production example 1, 100 parts by weight of a 0.15 M CaCl ₂ aqueous solution and 0.15 M-SrCl ₂ were used instead of 100 parts by weight of a 0.3 M CaCl ₂ aqueous solution. Aqueous solution 10
In the same manner except that 0 parts by weight was used, inorganic compound fine particles 10 containing Ag ions only in the vicinity of the surface were prepared. Table 2 shows properties of the obtained inorganic compound fine particles 10.

[0120]

[Table 2]

[Toner Production Example 1] With respect to 100 parts by weight of black ground toner particles 2, the specific surface area by the BET method was 2
00m ² / g 0.8 parts by weight of the surface of the silica matrix with a silane coupling agent and silicone oil hydrophobic silica hydrophobized and the specific surface area is in the 120 m ² / g is, the inorganic compound fine particles 1 External addition of 0.3 parts by weight gave toner 1.

[Toner Production Examples 2 to 10] With respect to 100 parts by weight of the black ground toner particles 2, 0.8 parts by weight of the hydrophobic silica used in Toner Production Example 1 and 0 parts of each of the inorganic compound fine particles 2 to 10 were used. 0.3 parts by weight were externally added to obtain toners 2 to 10.

[Toner Production Example 11] To 100 parts by weight of the black ground toner particles 2, 1.1 parts by weight of the hydrophobic silica used in Toner Production Example 1 was externally added to obtain Toner 11.

[Toner Production Example 12] With respect to 100 parts by weight of the black ground toner particles 1, 0.8 parts by weight of the hydrophobic silica used in Toner Production Example 1 and 0.1 parts by weight of the inorganic compound fine particles 1 were added.
The toner 12 was obtained by externally adding 3 parts by weight.

[Toner Production Example 13] To 100 parts by weight of the black polymerized toner particles 1, 1.2 parts by weight of the hydrophobic silica used in Toner Production Example 1 and 0.1 parts of the inorganic compound fine particles 1 were added.
The toner 13 was obtained by externally adding 5 parts by weight.

[Toner Production Examples 14 to 16] With respect to 100 parts by weight of black polymerized toner particles 2 to 4, 1.2 parts by weight of the hydrophobic silica used in Toner Production Example 1 and 0 parts of inorganic compound fine particles 1 were used. 0.5 parts by weight externally added, toners 14 to 16
I got

[Toner Production Example 17] To 100 parts by weight of the black polymerized toner particles 5, 0.8 parts by weight of the hydrophobic silica used in Toner Production Example 1 and 0.1 part of the inorganic compound fine particles 1 were added.
The toner 17 was obtained by externally adding 3 parts by weight.

[0128]

[Table 3]

<Embodiment 1> 600d electrophotographic apparatus
pi laser beam printer (Canon: LBP-8)
60) was prepared. Process speed is 47mm / s
It is.

The cleaning rubber blade in this process cartridge was removed, the charging method of the apparatus was set to direct charging performed by contacting a rubber roller, and the applied voltage was set to a DC component (-1200 V).

Next, the developing portion of the process cartridge was modified. Medium resistance rubber roller (16φ, hardness ASKER) made of silicone rubber in which carbon black is dispersed instead of the stainless steel sleeve as the toner supply body
C45 °, resistance 10 ⁵ Ω · cm) was used as a toner carrier, and was in contact with the photoreceptor. The developing nip width at this time is about 2 m
m. The rotation peripheral speed of the toner carrier is the same in the contact portion with the photoconductor, and the toner carrier is driven to be 130% of the peripheral speed of the photoconductor.

The photosensitive member used here is 30φ, 2
A 54 mm Al cylinder was used as a substrate, and layers having the following constitutions were sequentially laminated by dip coating on the substrate to prepare a photoreceptor.

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

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

(3) Charge generation layer: mainly composed of a titanyl phthalocyanine pigment having absorption in a long wavelength region dispersed in a butyral resin. The film thickness is 0.6 μm.

(4) Charge transporting layer: Mainly a hole transporting triphenylamine compound dissolved in a polycarbonate resin (molecular weight 20,000 according to Ostwald viscosity method) at a weight ratio of 8:10. Film thickness 20 μm.

As means for applying the toner to the toner carrier, an application roller made of urethane foam rubber was provided in the developing device, and was brought into contact with the toner carrier. For the application roller,
A voltage of about -550 V is applied. Further, a stainless steel blade coated with a resin for controlling the coat layer of the toner on the toner carrier was attached so that the contact pressure with the toner carrier was about 20 g / cm. An outline is shown in FIG. Further, the applied voltage at the time of development is changed to a DC component (-450 V).
Only.

The electrophotographic apparatus was modified and the process conditions were set as described below so as to be adapted to the modification of the process cartridge.

The modified device uniformly charges the image carrier using a roller charger (only DC is applied). After charging, an image is exposed to a laser beam to form an electrostatic latent image by exposing the image portion to a visible image with toner, and then the toner image is transferred to a transfer material by a roller to which a voltage is applied. An outline is shown in FIG.

In addition, the charging potential of the photosensitive member is set to -6
The voltage was set to 00V, and the bright portion potential was set to -150V. 75 g / m ² paper was used as the transfer material.

Using the image forming apparatus, a durability test was performed using the toner 12 under the conditions of a temperature of 23 ° C. and a humidity of 60%.

The durability was evaluated by performing character printing at a print area ratio of 6%, and determining the number of sheets on which charging unevenness occurred due to contamination of the charging member on the halftone image and the solid black image density by Macbeth at that time. . When no stain was generated, image printing was continued up to 1500 sheets. The greater the number of sheets on which charging unevenness has occurred, and the higher the image density at that time, the better the durability.

Further, the amount of toner adhering to the charging roller at the end of the durability test was measured. Dirt on the charging roller is determined by the toner weight per unit area on the charging roller (mg / c).
m ² ) was measured.

The transferability in the initial stage of the durability was determined by removing the transfer residual toner on the photoreceptor at the time of solid black image development by taping with a Mylar tape, peeling off the tape, and applying the Macbeth density of the tape alone to the Macbeth density based on the tape. The evaluation was performed by subtracting the concentration. Therefore, the smaller the value, the better the transferability.

The resolving power in the early stage of durability was evaluated by the reproducibility of a small-diameter isolated dot at 600 dpi, in which the electric field was easily closed by the latent image electric field, and it was difficult to reproduce. A: 5 or less defects in 100 B: 6 to 10 defects in 100 C: 11 to 20 defects in 100 D: More than 20 defects in 100 Then, dirt generated on the back side of the image sample from the initial stage to the durability of 100 sheets was observed, and the number of generated sheets was counted.

When an experiment was conducted under the above conditions and evaluation method, the toner 13 showed very excellent performance in both initial image characteristics and durability. Table 4 shows the results.

<Examples 2 to 15 and Comparative Examples 1 and 2> Similar to Example 1 except that toners 1 to 8, 10, 12, 14 to 17 (Example) and toners 9 and 11 (Comparative Example) were used. An experiment was performed. Table 4 shows the results.

[0148]

[Table 4]

Example 16 Ferrite carrier coated with polymerized toner 13 and 0.5 part by weight of silicone resin per 100 parts by weight of carrier core material (average particle size 46 μm)
Are mixed so that the toner concentration in the developer becomes 5% to produce a two-component developer, and the electrophotographic copying machine CLC-700 (manufactured by Canon) having a corona charger is modified to form a cleaning unit. A detachable printing test was performed on only 10,000 black-and-white images using an original document having an image area ratio of 20% under an environment of a temperature of 23 ° C. and a humidity of 60%.

As a result, the initial charge amount was −29.8 μC / kg → the charge amount after outputting 10,000 sheets−29.5 μC / kg, the initial image density was 1.61 → the image density after outputting 10,000 sheets was 1. 60, and a high-resolution image free of image quality defects such as uneven charging and fog was stably obtained.

[0151]

As described above, when the toner of the present invention is used, a high-resolution image can be obtained without causing image defects such as charging unevenness and deterioration of the developing characteristics even in the simultaneous cleaning image forming method. , And excellent durability. Further, even when used as a two-component developer, a high-definition image can be obtained for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic view of a process of an electrophotographic apparatus preferably used for an image forming method of inorganic compound fine particles.

FIG. 2 is an explanatory diagram of an apparatus for measuring the resistance of inorganic compound fine particles.

FIG. 3 is an explanatory diagram of an apparatus for measuring a charge amount of a toner.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 developing device 101 coat layer controlling developing blade (made of resin-coated stainless steel) 102 toner carrier (medium resistance rubber roller) 103 toner applying roller 104 toner 105 transfer material 106 transfer roller 107 fixing pressure roller 108 fixing heat roller 109 Photoconductor 110 Charging roller 111 Laser beam 112 Transfer toner 113 Transfer residual toner 115 Bias power supply for charging roller 116 Bias power supply for transfer roller 117 Bias power supply for toner carrier 118 Bias power supply for toner application roller d Sample thickness A Measurement cell 21, 22 Electrode 23 Insulator 24 Ammeter 25 Electrometer 26 Power supply 27 Sample 28 Cell outer frame 31 Suction machine 32 Measuring container 33 500 mesh screen 34 Lid 35 Vacuum gauge 36 Suction port 37 Condenser 38 Electrometer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masanori Ito 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H005 AA06 AA08 AA15 AB06 CA14 CA25 DA07 DA10 EA01 EA03 EA05 EA07 2H077 AA37 AC04 AD02 AD06 AD13 AD17 AD35 EA01 EA11 EA15 FA13 FA22 FA25 FA26 FA29

Claims (29)

[Claims] 1. A toner comprising toner particles containing at least a binder resin and a colorant and fine particles of an inorganic compound, wherein the inorganic compound comprises at least a phosphoric acid compound. toner. 2. The toner according to claim 1, wherein the cation constituting the inorganic compound contains at least a metal ion selected from alkaline earth metals. 3. The inorganic compound is composed of at least two or more cations, at least one of which is of group IB and VI.
3. The toner according to claim 1, wherein the toner is an ion of a metal selected from Group II metal elements. 4. The inorganic compound is poorly water-soluble fine particles containing a phosphate of an alkaline earth metal as a main component, and a part of the alkaline earth metal is selected from Group IB and Group VIII metal elements. 4. The toner according to claim 1, wherein the toner is substituted with a metal. 5. The inorganic compound is poorly water-soluble fine particles containing a phosphate of an alkaline earth metal as a main component, and a part of the alkaline earth metal near the surface of the fine particles is composed of IB and V.
4. The toner according to claim 1, wherein the toner is substituted with a metal selected from Group III metal elements. 6. The resistance of the inorganic compound is 10 ⁴ to 10 ¹² Ω.
The toner according to any one of claims 1 to 5, wherein the toner particle size is cm. 7. The inorganic compound having a number average particle size of 0.05 to 0.05.
The toner according to claim 1, wherein the thickness is 2 μm. 8. The method according to claim 1, wherein the value of the shape factor SF-1 of the toner particles measured by an image analyzer satisfies 100 <SF-1 ≦ 160. toner. 9. The method according to claim 1, wherein the value of the shape factor SF-2 of the toner particles measured by an image analyzer satisfies the following condition: 100 <SF-2 ≦ 140. toner. 10. The toner particles having a softening point of 40 to 90.
The toner according to any one of claims 1 to 9, further comprising a wax at a temperature of ℃. 11. The toner according to claim 10, wherein the content of the wax is 0.1 to 50% by weight based on the whole toner. 12. The toner particles having a weight average particle diameter of 1 to 9
The toner according to claim 1, wherein the toner has a μm. 13. The toner according to claim 1, wherein a part or the whole of the toner particles is formed by a polymerization method. 14. A charging step for charging the electrostatic image carrier, an exposure step for forming an electrostatic latent image on the electrostatic image carrier by irradiation of light energy, An image forming method comprising: a developing step of developing the electro-latent image and the toner thin-coated on the toner carrier while contacting the toner image; and a transfer step of transferring the toner image to a transfer material. An image forming method comprising: toner particles containing a resin and a colorant; and fine particles of an inorganic compound, wherein the inorganic compound is composed of at least a phosphate compound. 15. The image forming method according to claim 14, further comprising a cleaning step of removing transfer residual toner remaining on the electrostatic image carrier after the transfer step from the electrostatic image carrier. 16. The method according to claim 15, wherein the cleaning step is performed after the transfer step and before the charging step by a cleaning member in contact with the electrostatic image carrier.
2. The image forming method according to 1., 17. The cleaning and cleaning step, which is a developing and cleaning step performed by the toner carrier in the developing step, is performed on the electrostatic image carrier after the transfer step and before the charging step, and after the charging step and before the developing step. The image forming method according to claim 15, wherein the method does not include a step of performing cleaning with a cleaning member that contacts the image forming apparatus. 18. The image forming method according to claim 14, wherein the cation constituting the inorganic compound contains at least a metal ion selected from alkaline earth metals. 19. The inorganic compound is composed of at least two or more cations, at least one of which is a group IB and V
19. The image forming method according to claim 14, wherein the ions are ions of a metal selected from Group III metal elements. 20. The inorganic compound is poorly water-soluble fine particles containing a phosphate of an alkaline earth metal as a main component, and a part of the alkaline earth metal is selected from Group IB and Group VIII metal elements. The image forming method according to any one of claims 14 to 19, wherein the image is replaced with a metal. 21. The inorganic compound is poorly water-soluble fine particles containing a phosphate of an alkaline earth metal as a main component, and a part of the alkaline earth metal near the surface of the fine particles has a group IB or VIII. 20. The image forming method according to claim 14, wherein the substrate is substituted with a metal selected from metal elements. 22. The resistance of the inorganic compound is 10 ⁴ to 10 ^12.
22. The image forming method according to claim 14, wherein the value is Ω · cm. 23. The inorganic compound having a number average particle size of 0.05
The image forming method according to any one of claims 14 to 22, wherein the thickness is from 2 to 2 m. 24. The method according to claim 14, wherein the value of the shape factor SF-1 of the toner particles measured by the image analyzer satisfies 100 <SF-1 ≦ 160. Developed image forming method. 25. The method according to claim 14, wherein the value of the shape factor SF-2 measured by the image analyzer of the toner particles satisfies 100 <SF-2 ≦ 140. Developed image forming method. 26. The toner particles having a softening point of 40 to 90.
The method according to any one of claims 14 to 25, further comprising a wax at a temperature of ° C. 27. The method according to claim 14, wherein the content of the wax is 0.1 to 50% by weight based on the whole toner. 28. A toner according to claim 28, wherein said toner particles have a weight average particle diameter of 1 to 9.
28 .mu.m.
The developed image forming method according to any one of the above. 29. The toner according to claim 14, wherein a part or the whole of the toner particles is formed by a polymerization method.
The developed image forming method according to any one of the above.