JPH11295922A - Non-magnetic toner for developing electrostatic latent image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a stable high picture quality capable of keeping fluidity and charging property and hardly generating a picture noise over a long period of time by constituting the toner with materials having a specified surface property and a specified ratio of (bulk density at the time of compression)/(true density) and an adhesion stress of a specified range. SOLUTION: The surface property satisfies the formula; D/d50>=0.40. where D=6/(ρ.S), and (the bulk density at the time of 1 kg/cm<2> compression)/(the true density (ρ))×100>=45; and the adhesion stress at the time of 1 kg/cm<2> compression satisfies <=6 g/cm<2> . In the formula, D is a converted particle size (μm) from a BET specific surface area assuming that a shape of the toner is a sphere. The d50 is a 50% equivalent particle size (μm) of a relative weight distribution by particle size; the ρ is the true density (g/cm<3> ); the S is the BET specific surface area (m<2> /g) respectively. A binder resin, a coloring agent and the other desired additives are mixed, kneaded, pulverized and classified by a conventional method to obtain particles having a desired particle size and the particles are subjected to an instantaneous heat treatment. The particle size is 4-10 μm, preferably 5-9 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a developer (toner) for developing an electrostatic latent image used for electrophotography, electrostatic printing and the like.

[0002]

2. Description of the Related Art One-component development is a system in which a thin layer of charged toner formed on a sleeve passes through a pressure contact gap between a developing sleeve and a toner regulating blade and develops an electrostatic image formed on a photoreceptor. Since the charging of the toner and the formation of the thin toner layer on the developing sleeve are performed at the pressure contact portion of the toner regulating blade, a large stress is applied to the toner. Due to this stress, the fluidity deteriorates due to the burial of the post-treatment agent and the generation of small diameter components due to the cracking of the toner, and the thin layer forming ability of the toner is reduced, causing unevenness of the thin layer. However, there was a problem that a uniform thin layer could not be formed by fusing, and vertical stripe noise was generated on an image.

On the other hand, in recent years, high definition and high image quality of (color) copying machines and (color) printers have been demanded.
It is required to reduce the diameter of the toner. At the same time, with the increase in speed, low-temperature fixability by reducing power consumption is required, and a toner having a lower softening point is required. .

In order to solve such a problem, a technique for making a toner shape spherical has recently been developed. By spheroidizing the toner, the disintegration of the toner due to the stress is reduced, and the generation of the small diameter component is suppressed, and the decrease in the fluidity due to the small diameter can be suppressed.

More specifically, a method for producing a spherical toner in a wet system by a suspension polymerization or emulsion polymerization method (Japanese Patent Laid-Open No. 1-2
No. 57857) and a technique of heat-treating a pulverized toner to make it spherical (Japanese Patent Publication No. 4-27897).
(JP-A-6-317928) has been proposed.

[0006] In recent years, higher image quality has been demanded for copiers and printers from the initial stage to the endurance time more than before. In addition, high speed and high durability have been demanded, and it is necessary to improve the toner's stress resistance, which leads to image noise, such as sticking on a toner carrier. Furthermore, when a low-temperature fixing resin required for a full-color toner and a low-temperature fixing toner is used in recent years, these required characteristics become more severe for the toner, and the burial of the post-processing agent is accelerated at the time of durability, and part of the toner is broken. As a result, a small-diameter component of the toner is generated, and the flow characteristics of the toner deteriorate. Further, there has been a problem that the charging characteristics of the toner deteriorate, and the low charge amount and the reverse charge amount component increase. As a result, there is a problem that the toner component is fused to the surface of the toner carrier and the surface of the toner regulating member, and the thin layer of the toner cannot be formed uniformly. The occurrence of the toner fusion deteriorates at an accelerated rate due to an increase in the small diameter component and the reversely charged component. The problem to be solved by the present invention is to provide a toner using a resin having a low-temperature softening point used in a full-color toner and a low-temperature fixing toner. It can maintain stable performance for a long time with respect to the characteristics. That is, by suppressing the burying speed of the post-treatment agent on the toner surface, and by suppressing the occurrence of cracking of the toner, the toner surface characteristics are stably maintained for a long time, and the necessary flow characteristics and charging characteristics are required. Is to ensure.

[0007]

SUMMARY OF THE INVENTION In the present invention, a stable fluidity is ensured by improving the smoothness of the surface state of the toner and the uniformity of the surface properties, so that the toner at the time of forming a thin toner layer is formed. Uniformity of the transport amount (uniformity in each area on the toner carrier) and a uniform filling state are achieved. Further, by suppressing the variation in the particle properties of each toner, the uniformity of the surface of each particle is improved, so that the surface charge density of the toner becomes uniform,
Variation in chargeability is reduced. As a result, the phenomenon that the small-diameter component having a relatively high charge amount is first supplied to the toner carrier and consumed is suppressed, and the change in the toner particle size consumed from the initial stage to the endurance is suppressed. (Selection of the toner particle size is reduced.) Further, by controlling the relationship of bulk density / true density at the time of toner compression to an area defined in the claim, uniformity of the filling state of the thin layer is improved, The pressure applied to each toner particle when regulating the thin toner layer on the toner carrier by the toner regulating member can be made uniform. As a result, the conditions for applying the charge to each toner particle become uniform, and as a result, the surface charge density of the toner becomes uniform. In addition, since the pressure applied to the toner is uniform, the localization of the pressure can prevent excessive stress from being applied to some of the toner particles. Therefore, the required fluidity and chargeability can be maintained for a long period of time because cracking of the toner can be suppressed.
As a result, stable high image quality is achieved without generating image noise over a long period of time.

[0008]

According to the present invention, the surface texture has the following conditional expression [I]: D / d50 ≧ 0.40, where D = 6 / (ρ · S) [I] (where D is Converted particle size (μm) from BET specific surface area assuming that the shape of toner is spherical; d50 is 50% relative particle size (μm) of relative weight distribution by particle size; ρ is true density (g / c)
m ³ ); S represents a BET specific surface area (m ² / g), respectively. Non-magnetic toner characterized in that (bulk density / true density (ρ) at compression of 1 kg / cm ² ) × 100 ≧ 45; and adhesive stress at compression of 1 kg / cm ² satisfies 6 g / cm ² or less. About.

[0009]

By making the shape of the toner spherical, enhancing the surface smoothness, and making the adhesion state of the post-processing uniform, the uniformity of the filling state when the toner layer is compressed is promoted, and the pressure from the outside is reduced. The pressure is evenly distributed to each toner particle without local excessive force being applied to a part of the toner particles.
As a result, the toner particles are uniformly charged in the toner thin layer regulating section, the stress applied to the toner in the toner thin layer regulating section and the developing area is alleviated, and the generation of small particle size components caused by toner cracks is generated. Suppress. Suppresses the burying speed of the post-treatment agent on the toner surface and suppresses the occurrence of toner cracks, etc., so that the toner surface characteristics are stably maintained over a long period of time, and the necessary flow characteristics and charging characteristics are secured. it can. As a result, stable high image quality can be achieved without generating image noise over a long period of time.

The toner particles of the present invention have the following surface condition: Conditional expression [I]: D / d50 ≧ 0.40, where D = 6 / (ρ · S) [I] (where D is the shape of the toner) Is a sphere, the converted particle size (μm) from the BET specific surface area; d50 is 50% relative particle size (μm) of relative weight distribution by particle size; ρ is true density (g / c)
m ³ ); S represents a BET specific surface area (m ² / g), respectively. ), The surface smoothness is very high and pores and cracks are reduced. In order to obtain such properties,
A binder resin, a colorant, and other desired additives are mixed, kneaded, crushed, and classified by a conventional method to obtain particles having a desired particle size.In the present invention, the particles obtained as described above are used. It is effective to carry out instant heat treatment.

The particle size is 4 to 10 μm, preferably 5 to 10 μm.
９9 μm. The particles obtained at this stage have almost the same particle size distribution even after being subjected to the instantaneous heat treatment.

The classifying step may be performed after performing the instantaneous heating treatment in the present invention. At this time, it is preferable to use a pulverizing apparatus capable of spheroidizing the particles to be pulverized as a pulverizing apparatus used in the pulverizing step, since it is easy to control the instantaneous heat treatment performed thereafter. Examples of such an apparatus include an innomizer system (manufactured by Hosokawa Micron Corporation) and a crypton system (manufactured by Kawasaki Heavy Industries, Ltd.). Further, by using a classifier capable of spheroidizing particles to be treated as a classifier used in the classifying step, control of circularity and the like becomes easy. Examples of such a classifier include a teaplex classifier (manufactured by Hosokawa Micron).

[0013] Further, in combination with the instantaneous heating treatment shown in the present invention, it may be combined with various treatments in a surface modifying apparatus for various developers. These surface modification devices include a hybridization system (Nara Machinery Co., Ltd.), a Cryptron Cosmos system (Kawasaki Heavy Industries, Ltd.), and an inomizer system (Hosokawa Micron).
Surface modification equipment using a high-speed air-flow impact method, such as a mechanofusion system (manufactured by Hosokawa Micron), mechanomill (manufactured by Okada Seiko), etc. A surface modification device to which a wet coating method of Seimei Engineering Co., Ltd.) or Coatmizer (Freund Sangyo Co., Ltd.) is applied can be used in appropriate combination.

According to the present invention, the shape of the toner particles obtained by the kneading-pulverization method is controlled to a spherical and uniform shape by performing an instantaneous heat treatment, and the pores on the toner surface are further reduced. And smoothness can be increased.
Due to this, the charging uniformity and image performance are excellent,
In addition, a toner that achieves stable image performance over a long period of time without the occurrence of selective development in which toner having a specific particle size and shape in a developer and a specific charge amount is consumed first does not occur. it can.

Conventionally, there has been known an example of performing surface modification by heat. In many cases, a developer is supplied while a hot air stream is circulating. In this case, the developers are liable to agglomerate with each other, and the shape after the processing has a large variation. Also,
By dispersing and supplying developer particles in a hot air stream,
A method is known in which the surface of the developer particles is melted and the developer particles are instantaneously spheroidized. It is also known that the surface of the developer particles is previously treated with hydrophobic silica or the like in order to improve the dispersion state of the developer particles in hot air. However, even with these methods, sphericity and its uniformity could not be achieved in order to dramatically improve the developer characteristics.

In the instant heat treatment used in the present invention, the developer is surface-modified by heat by dispersing and spraying toner particles in hot air with compressed air, and the surface properties which cannot be achieved by the conventional method are obtained. , Sphericity and its uniformity.

A schematic configuration diagram of an apparatus for performing an instantaneous heat treatment will be described with reference to FIGS. As shown in FIG.
The high-temperature, high-pressure air (hot air) prepared by the hot-air generator 101 is injected from a hot-air injection nozzle 106 through an introduction pipe 102. On the other hand, the toner particles 105
Is transported by a predetermined amount of pressurized air through an introduction pipe 102 ′ and sent into a sample injection chamber 107 provided around the hot air injection nozzle 106.

As shown in FIG. 2, the sample injection chamber 107 has a hollow donut shape, and a plurality of sample injection nozzles 103 are arranged at equal intervals on the inner wall thereof. The toner particles sent to the sample ejection chamber 107 are diffused and uniformly dispersed in the ejection chamber 107, and the plurality of sample ejection nozzles 1
03 is injected into the hot air stream. In addition, in FIG. 2, 4 has shown the staying powder.

In this case, the sample injection nozzle 1 is set so that the jet flow of the sample injection nozzle 103 does not cross the hot air flow.
03 is preferably provided with a required inclination. Specifically, it is preferable that the toner jet flow is jetted so as to follow the hot air stream to some extent, and the angle between the toner jet stream and the flow direction of the central region of the hot air stream is 20 to 40 °, preferably 2 °.
5-35 ° is preferred. If it is wider than 40 °, the toner jet flow will be jetted across the hot air flow, and will collide with the toner particles jetted from other nozzles, causing aggregation of the toner particles. If the width is too narrow, toner particles that cannot be taken into the hot air are generated, and the shape of the toner particles becomes non-uniform.

Further, a plurality of sample injection nozzles 103 are required, and at least three or more and four or more are preferable. By using a plurality of sample injection nozzles, it is possible to uniformly disperse the toner particles in the hot air stream, and it is possible to reliably perform the heat treatment for each toner particle. As for the state ejected from the sample ejecting nozzle, it is desirable that it is widely diffused at the time of ejection and is dispersed throughout the hot air flow without colliding with other toner particles.

The toner particles ejected in this way are instantaneously brought into contact with high-temperature hot air and uniformly heated. Here, the term “instantaneous” refers to a time during which the necessary modification (heating treatment) of the toner particles is achieved and the aggregation of the toner particles does not occur, which varies depending on the processing temperature and the concentration of the toner particles in the hot air stream. , Usually 2 seconds or less, preferably 1 second or less. This instantaneous time is expressed as the residence time of the toner particles until the toner particles are ejected from the sample ejection nozzle and introduced into the introduction pipe 102 ". When the residence time exceeds 2 seconds, coalesced particles are generated. It will be easier.

Next, the instantaneously heated toner particles are immediately cooled by the cool air introduced from the cooling air introduction unit 108, and adhere to the apparatus wall or agglomerate with each other without passing through the introduction pipe 102 "to the cyclone 109". And then stored in the product tank 111. After the toner particles have been collected, the transport air further passes through the bag filter 112 to remove fine powder, and is then discharged to the atmosphere via the blower 113. The cyclone 109 is preferably provided with a cooling jacket through which cooling water flows to prevent aggregation of toner particles.

Other important conditions for performing the instantaneous heat treatment are the amount of hot air, the amount of dispersed air, the concentration of the dispersed air, the processing temperature, the temperature of cooling air, the amount of suction air, and the temperature of cooling water.

The hot air flow is the amount of hot air supplied by the hot air generator 101. It is preferable to increase the amount of hot air in order to improve the uniformity of heat treatment and the processing capacity.

The amount of dispersed air is the amount of air sent into the inlet pipe 102 'by pressurized air. Although depending on other conditions, it is preferable that the amount of the dispersed air be reduced and heat-treated because the dispersed state of the toner particles is improved and stabilized.

The dispersion concentration refers to the dispersion concentration of the toner particles in the heat treatment region (specifically, the nozzle discharge region). The preferred dispersion concentration depends on the specific gravity of the toner particles, and the value obtained by dividing the dispersion concentration by the specific gravity of each toner particle is 50 to 300 g.
/ M ³ , preferably 50 to 200 g / m ³ .

The processing temperature refers to the temperature in the heat treatment area. In the heat treatment region, a temperature gradient actually exists from the center to the outside, but it is preferable to reduce the temperature distribution for the treatment. From the device side, it is preferable to supply the wind in a stabilized laminar flow state by a stabilizer or the like. In the case of a non-magnetic toner using a binder resin having a sharp molecular weight distribution, for example, a binder resin having a weight average molecular weight / number average molecular weight of 2 to 20, the glass transition point of the binder resin + 100 ° C. or more to the glass transition point + 300 ° C. It is preferable to perform the treatment in the peak temperature range. More preferably, the treatment is carried out in a peak temperature range from the glass transition point of the binder resin + 120 ° C or more to the glass transition point + 250 ° C. The peak temperature range refers to the maximum temperature in a region where the toner comes into contact with hot air.

When wax is added to toner particles, coalesced particles tend to be generated. Therefore, the fluidization treatment before the heat treatment (particularly, a fluidizing agent having a large particle size component) is set to be relatively large. Tuning, such as setting the dispersion concentration at the time of processing to be low, is important in obtaining uniform toner particles with reduced shape and shape variation. This operation becomes more important when a binder resin having a relatively wide molecular weight distribution is used or when the processing temperature is set to be higher in order to increase the sphericity.

The cooling air temperature is the temperature of the cooling air introduced from the cooling air introduction unit 108. After the instantaneous heat treatment, the toner particles are preferably returned to an atmosphere below the glass transition point by cooling air so as to be instantaneously cooled to a temperature region where aggregation or coalescence of the toner particles does not occur. For this reason, the cooling air is cooled at a temperature of 25 ° C. or lower, preferably 15 ° C. or lower, more preferably 10 ° C. or lower. However,
If the temperature is lowered more than necessary, dew condensation may occur depending on the conditions, and conversely, side effects occur, so care must be taken. In such an instantaneous heat treatment, in addition to the cooling by the cooling water in the apparatus described below, the time during which the binder resin is in the molten state is extremely short, so that the particles do not adhere to each other and to the walls of the heat treatment apparatus. As a result, the stability during continuous production is excellent, the frequency of cleaning the manufacturing apparatus can be extremely reduced, and the yield can be controlled stably with high yield.

The suction air flow refers to air for conveying the toner particles processed by the blower 113 to the cyclone. It is preferable to increase the amount of the suction air from the viewpoint of reducing the cohesiveness of the toner particles.

The cooling water temperature refers to cyclones 109 and 11
4 and the temperature of the cooling water in the cooling jacket provided in the inlet pipe 102 ″.) The cooling water temperature is 25 ° C.
Or less, preferably 15 ° C or less, more preferably 10 ° C
It is as follows.

In order to have a high sphericity (circularity) and a small variation in the shape, and to more easily control the surface smoothness and the adhesive stress, it is preferable to further devise the following measures.

The amount of toner particles supplied into the hot air stream is controlled to be constant so that pulsation or the like is not generated. For this purpose, (i) using a plurality of combinations of the table feeder, the vibration feeder, and the like used in 115 in FIG.
Improve quantitative supply. If the table feeder and the vibratory feeder can be used to perform high-precision quantitative supply, it is possible to connect the pulverization or classification step and supply the toner particles to the heat treatment step online as it is;

(Ii) After supplying the toner particles with compressed air,
Before the toner particles are supplied into the hot air, the toner particles are supplied to the sample supply chamber 107.
Re-dispersed within to increase uniformity. For example, means of redispersion by secondary air, provision of a buffer section to make the dispersion state of toner particles uniform, or redispersion by a coaxial double tube nozzle or the like is adopted;

Optimizing and uniformly controlling the dispersion concentration of toner particles when sprayed and supplied in a hot air stream. To do this:

(I) The hot air stream is supplied uniformly from all directions and in a highly dispersed state. More specifically, when supplying from a dispersion nozzle, a nozzle having a stabilizer or the like is used to improve the dispersion uniformity of toner particles dispersed from each nozzle;

(Ii) In order to make the concentration of toner particles dispersed in the hot air stream uniform, the number of nozzles should be at least three, preferably four or more, as described above, and should be as large as possible. They are arranged symmetrically with respect to the direction. 3
The toner particles may be supplied uniformly from a slit provided in the entire circumference of 60 degrees;

The temperature distribution of the hot air in the region where the toner particles are processed is controlled so that uniform heat energy is applied to all the particles, and the hot air is controlled in a laminar flow state. . To do this:

(I) To reduce the temperature variation of the heat source for supplying the hot air; (ii) To make the straight pipe portion before the hot air supply as long as possible. Alternatively, it is preferable to provide a stabilizer near the hot air supply port for stabilizing the hot air. Further, FIG.
Is an open system, which tends to diffuse hot air in a direction in which it comes into contact with outside air, so that the hot air supply port may be narrowed as necessary;

The toner particles have been subjected to a fluidization treatment so as to maintain a uniform dispersion state during the heat treatment. (I) In order to ensure the dispersion and fluidity of the toner particles, it is preferable to use various organic / inorganic fine particles of 1/20 or less, preferably 1/50 or less of the particle size of the toner particles.

Examples of the inorganic fine particles include silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, calcium carbide, and diamond carbon lactam. Various carbides, boron nitride, titanium nitride, various nitrides such as zirconium nitride, borides such as zirconium boride, oxides,
Various oxides such as titanium oxide, calcium oxide, magnesium oxide, zinc oxide, copper oxide, aluminum oxide, silica, colloidal silica, various titanate compounds such as calcium titanate, magnesium titanate, strontium titanate, molybdenum disulfide, etc. Sulfide, magnesium fluoride, fluoride such as fluorocarbon, aluminum stearate, calcium stearate, zinc stearate,
Various non-magnetic inorganic fine particles such as various metal soaps such as magnesium stearate and talc and bentonite can be used alone or in combination. Particularly in the case of inorganic fine particles such as silica, titanium oxide, alumina and zinc oxide,
Silane coupling agents, titanate coupling agents,
Conventionally used hydrophobizing agents such as silicone oil, silicone varnish, etc., furthermore, fluorinated silane coupling agents, or fluorinated silicone oils, further coupling agents having amino groups or quaternary aluminum bases, modified silicones It is preferable that the surface is treated with a treatment agent such as oil by a known method.

Examples of the organic fine particles include styrene-based, (meth) acryl-based, benzoguanamine, melamine, and the like, which are granulated by a wet polymerization method such as an emulsion polymerization method, a soap-free emulsion polymerization method, a non-aqueous dispersion polymerization method, or a gas phase method. Various organic fine particles such as Teflon, silicon, polyethylene, and polypropylene can also be used. The organic fine particles also have a function as a cleaning aid.

The amount of the fluidizing agent added is 0.1 parts by weight based on 100 parts by weight of the developer particles before the heat treatment.
５5 parts by weight, preferably 0.3-3 parts by weight, but it is preferable to adjust the amount before and after the heat treatment described below.

In particular, inorganic fine particles (particularly, hydrophobic silica fine particles) having an average primary particle diameter of 20 nm or less (BET specific surface area of 100 m ² / g or more) and subjected to a hydrophobic treatment are preferable.

(Ii) It is preferable that the mixing treatment for improving the dispersion / fluidity exists uniformly and strongly adhered to the surface of the toner particles without being fixed.

Even when the surface of the toner particles receives heat, particles that do not soften because the spacer effect between the toner particles can be maintained on the surface of the toner particles are present on the surface of the toner particles.
To do this:

(I) It is preferred to add fine particles which have a larger particle size than the various organic / inorganic fine particles shown above and which do not soften at the processing temperature. Due to the presence of the present particles on the surface of the toner particles, even after starting to receive heat, the surface of the toner particles does not become a surface of only the complete resin component, and brings about a spacer effect between the toner particles,
Prevents agglomeration and coalescence of toner particles; furthermore, greatly contributes to reduction of adhesion stress and prevents toner aggregation.

(Ii) The amount of the large-diameter particles added is
0.2 to 5 parts by weight, preferably 00 parts by weight,
0.3 to 3 parts by weight are added.

The collection of the heat-treated product must be controlled so as not to generate heat. For this purpose: (i) The particles which have been heat-treated and cooled are cooled by a chiller in order to suppress heat generated in a piping system (particularly a radius portion) and a cyclone usually used for collecting toner particles. Is preferred.

In the processing of a magnetic toner having a small resin component that can contribute to heat treatment and having a relatively large specific gravity, the space to be heat-treated is surrounded in a cylindrical shape to substantially increase the processing time, It is preferable to perform the process twice.

By appropriately performing the instantaneous heating treatment as described above, the surface properties are given by the following conditional expression [I]: D / d50 ≧ 0.40, where D = 6 / (ρ · S) [I] (wherein , D is the particle diameter converted from the BET specific surface area (μm) assuming that the toner is spherical, d50 is the 50% relative particle diameter (μm) of the relative weight distribution by particle diameter, and ρ is the true density (g / g). c
m ³ ); S represents a BET specific surface area (m ² / g), respectively. ), Preferably, toner particles having a D / d50 satisfying 0.45 or more, and having an average circularity of 0.950 or more and a standard deviation of the average circularity of 0.040 or less are obtained.

More preferably, in the case of a color toner (including a black toner), the average circularity is 0.960 or more, and the average circularity and the standard deviation are 0.035 or less. The average circularity of the oilless fixing toner is 0.950 or more, and the standard deviation of the average circularity is 0.040 or less.

The D / d50 is an index indicating the presence or absence of pores on the surface or inside of the toner particles. If the toner has the above value, the toner may be broken around the pores or may be externally added to the recesses. There is no inconvenience such as the embedding of silica or the like as a fluidizing agent added as an agent, or the generation of fine powder due to the shaving of the convex portion.

The BET specific surface area was measured using Flowsorb 2300
Although the value measured with a model (manufactured by Shimadzu Corporation) is used,
If the measurement is performed by the same measurement principle and method, it does not mean that the measurement must be performed by the device.

The relative weight distribution (d50) for each particle size uses a value measured by (Coulta Multisizer; manufactured by Coulter Counter Co.), but if it is measured by the same measurement principle and method. It does not mean that it must be measured with the device.

The true density (ρ) is a value measured by an air comparison specific gravity meter (manufactured by Beckman Co., Ltd.), but if it is measured by the same measurement principle and method, it must be measured by the above-mentioned apparatus. It doesn't mean you have to.

The average circularity is represented by the following equation:

(Equation 1) The “perimeter of a circle equal to the projected area of a particle” and the “perimeter of a projected particle image” are flow particle image analyzers (FPIA-1000 or FIA).
PIA-2000; manufactured by Toa Medical Electronics Co., Ltd.) is shown in a value obtained by performing measurement in an aqueous dispersion system. The closer to 1, the closer to a true sphere. As described above, since the average circularity is obtained from “the perimeter of a circle equal to the projected area of a particle” and “the perimeter of a projected image of a particle”, the value accurately determines the shape of the toner particle, that is, the unevenness of the particle surface. It is an index to be reflected in. Further, since the average circularity is a value obtained as an average value of 3000 toner particles, the reliability of the average circularity in the present invention is extremely high. Note that, in the present specification, the average circularity does not have to be measured by the above device,
In principle, any device that can be determined based on the above equation may be used for measurement.

The standard deviation of the circularity refers to the standard deviation in the circularity distribution, and this value can be obtained simultaneously with the average circularity by the flow type particle image analyzer. The smaller the value is, the more uniform the toner particle shape is.

The above-mentioned instantaneous heating treatment is performed, and the uniformity of the toner surface properties and toner shape can be determined by using a general thermoplastic resin used for toner formation.
In the present invention, the glass transition point is 50 to 75 ° C, the softening point is 80 to 160 ° C, and the number average molecular weight is 1000 to 300.
00 and weight average molecular weight / number average molecular weight of 2 to 100
It is preferable to use a resin that is

In particular, when a full-color toner (including a black toner) is intended, a glass transition point of 50 to 75 ° C.
Softening point 80-120 ° C, number average molecular weight 2000-300
It is preferable to use a resin having a weight average molecular weight of 00 and a weight average molecular weight of 2 to 20.

When an oilless fixing toner is intended, a glass transition point of 50 to 75 ° C. and a softening point of 80 to 1
It is preferable to use a resin having a number average molecular weight of 1,000 to 10,000 and a weight average molecular weight / number average molecular weight of 30 to 100 at 60 ° C.

More preferably, the toner binder resin component has the above characteristics and an acid value (2 to 50 KOH mg).
/ G, preferably 3 to 30 KOH mg / g). By using a polyester resin having such an acid value, it is possible to improve the dispersibility of various pigments including carbon black and a charge control agent, and to obtain a toner having a sufficient charge amount. When the acid value is less than 2 KOHmg / g, the above-described effects are reduced, and when the acid value is more than 50 KOHmg / g, the stability of the toner charge amount against environmental changes, particularly humidity changes, is impaired.

In the present invention, in particular, in order to improve the fixability and the offset resistance as an oilless fixing toner, or to control the glossiness of an image in a full-color toner requiring light transmission. It is preferable to use two types of polyester resins having different softening points as the polyester resins. The oilless fixing toner has a softening point of 95 to improve the fixing property.
The first polyester resin having a softening point of 130 to 160 ° C. to improve offset resistance is used.
Is used. In this case the first
When the softening point of the polyester resin is lower than 95 ° C., the offset resistance and the reproducibility of dots are reduced, and
If the temperature is higher than 0 ° C., the effect of improving the fixing property becomes insufficient. If the softening point of the second polyester resin is lower than 130 ° C, the effect of improving the offset resistance becomes insufficient, and if it is higher than 160 ° C, the fixability decreases. From such a viewpoint, the softening point of the first polyester-based resin is preferably 100 to
At 115 ° C., the softening point of the second polyester resin is 135
１５155 ° C. The first and second polyester resins have a glass transition point of 50 to 75 ° C, preferably 55 to 75 ° C.
It is desirably 70 ° C. This is because if the glass transition point is low, the heat resistance of the toner becomes insufficient, and if the glass transition point is too high, the pulverizability at the time of production is lowered and the production efficiency is lowered.

The first polyester resin is a polyester resin obtained by polycondensing a polyhydric alcohol component and a polyhydric carboxylic acid component, particularly a bisphenol A alkylene oxide adduct as a polyhydric alcohol component. A polyester resin obtained by using as a main component at least one selected from the group consisting of only terephthalic acid, fumaric acid, dodecenylsuccinic acid, and benzocentric carboxylic acid as the carboxylic acid component is preferable.

Further, as the second polyester resin,
Using a mixture of a raw material monomer of a polyester resin, a raw material monomer of a vinyl-based resin, and a bi-reactive monomer that reacts with the raw material monomers of both resins, a condensation polymerization reaction to obtain a polyester resin in the same container and a vinyl-based resin are performed. A polyester resin obtained by performing the obtained radical polymerization reaction in parallel is preferred from the viewpoint of improving the dispersibility of the wax, the toughness, the fixability, and the offset resistance of the toner. The content of the vinyl resin in the second polyester resin is 5 to 5.
It is 40% by weight, preferably 10 to 35% by weight. When the content of the vinyl resin is less than 5% by weight, the fixing strength of the toner is reduced. When the content is more than 40% by weight, the offset resistance, the toughness of the toner, and the negative charge level are liable to occur. Become. In addition, when the wax is contained in the toner, the dispersibility of the polyethylene wax tends to decrease when the content of the vinyl resin is less than 5% by weight, and the dispersibility of the polypropylene wax tends to decrease when the content exceeds 40% by weight. is there.

The weight ratio of the first polyester resin to the second polyester resin is 7: 3 to 2: 8, preferably 6: 3.
It is preferable to set it to 4: 3: 7. By using the first polyester-based resin and the second polyester-based resin in such a range, the spread as a toner due to crushing at the time of fixing is small, the dot reproducibility is excellent, and the low-temperature and high-speed fixing properties are excellent. In the image forming apparatus described above, excellent fixability can be ensured. Also, excellent dot reproducibility can be maintained even when forming a double-sided image (when passing through the fixing device twice). If the proportion of the first polyester resin is smaller than the above range, the low-temperature fixability becomes insufficient and a wide fixability cannot be secured. If the proportion of the second polyester resin is smaller than the above range, the offset resistance tends to decrease and the toner is crushed at the time of fixing, and the dot reproducibility tends to decrease.

Conventionally, a full-color resin requiring translucency has used a sharp-melt type resin having a sharp molecular weight distribution, and a glossy pictorial image was reproduced by using such a resin. However, in recent years, there has been a case in which an image with reduced glossiness is required for a normal office color or the like. Such a requirement can be achieved, for example, by expanding the molecular weight distribution of the resin toward the polymer. In addition, as one of the specific measures, it can be achieved by using two or more kinds having different molecular weights in combination, and the resin properties finally combined have a glass transition temperature of 50 to 75 ° C and a softening point of 80 to 80.
120 ° C., a number average molecular weight of 2,500 to 30,000 and a weight average molecular weight / number average molecular weight of 2 to 20 can be suitably used. When the glossiness is reduced, the weight-average molecular weight / number-average molecular weight value is set to 4 or more and the melt viscosity curve is inclined, so that the glossiness control region with respect to the fixing temperature can be expanded. .

In addition, epoxy resins can be suitably used, especially in full-color toners. As the epoxy resin used in the present invention, a polycondensate of bisphenol A and epichlorohydrin can be suitably used.
For example, epomic R362, R364, R365, R
367, R369 (all manufactured by Mitsui Petrochemical Industries, Ltd.), Epotote YD-011, YD-012, YD-014,
YD-904, YD-017 (all manufactured by Toto Kasei)
Commercially available products such as Epicoat 1002, 1004, 1007 (all manufactured by Ciel Chemical Co., Ltd.) can also be used.

In the present invention, the softening point of the resin is determined by using a flow tester (CFT-500: manufactured by Shimadzu Corporation), using a die having a diameter (diameter of 1 mm, length of 1 mm) and a pressure of 20 μm.
kg / cm ² , 1 cm under the condition of a heating rate of 6 ° C./min.
^The temperature corresponding to 1/2 of the height from the outflow start point to the outflow end point when the sample No. ² was melted out was set as the softening point. The glass transition point was determined using a differential scanning calorimeter (DSC-200: manufactured by Seiko Instruments Inc.) as an alumina reference,
A sample of 10 mg was heated at a rate of 10 ° C./min for 20 minutes.
The temperature was measured between ℃ 120 ° C., and the shoulder value of the main endothermic peak was defined as the glass transition point. The acid value was determined by dissolving a 10 mg sample in 50 ml of toluene and titrating with a pre-specified N / 10 potassium hydroxide / alcohol solution using a mixed indicator of 0.1% bromthymol blue and phenol red. / 10 This is a value calculated from the consumption amount of potassium hydroxide / alcohol solution. The molecular weight (number average molecular weight, weight average molecular weight) is a value calculated by gel permeation permeation chromatography (GPC) in terms of styrene.

An external additive is added to the toner particles that have been subjected to the heat treatment as described above, and the bulk density at compression of 1 kg / cm ² / true density (ρ)) × 1
It is adjusted so that the value represented by 00 is 45 or more; and the adhesion stress at the time of compression of 1 kg / cm ² is 6 g / cm ² or less, preferably 5.6 or less. By doing so, it is possible to reduce agglomeration between toners, and by adjusting the bulk density in a compressed state of 1 kg / cm ² , which is equivalent to the state at the time of regulating the thin layer, the toner thin layer can be formed on the image carrier. It can be formed more evenly, preventing localization of stress,
Even during durability, the toner can be uniformly charged, and unevenness of the toner thin layer can be prevented. The above adjustment can be achieved by the above-mentioned instantaneous heat treatment, together with the shape and shape distribution of the toner and the properties of the toner surface, and the processing conditions such as the amount of the external additive added.

The bulk density at the time of compression of 1 kg / cm ² was measured by using a device for measuring the compression / tensile characteristics of a powder layer (Ag Robot: manufactured by Hosokawa Micron Corporation) under a condition described below. After filling the powder, compressing the upper cell from the vertical direction and holding the powder under a constant compressive stress, the density (g / g) calculated from the volume occupied by the compressed powder is obtained.
cm ³ ).

Measurement conditions: Sample amount: 6 g Environmental temperature: 23 ° C. Humidity: 50% Cell inner diameter: 25 mm Cell temperature: 25 ° C. Spring wire diameter: 1.0 mm Compression speed: 0.1 mm / sec Compressive stress: 1 kg / cm ² Compression holding time: 60 seconds

The adhesion stress was measured by using the same apparatus as the apparatus for measuring the bulk density, holding the powder under a pressure of 1 kg / cm ² under the following conditions, and then lifting the upper cell and breaking the powder layer. Means the maximum tensile stress g / cm ² .

Measurement conditions: Sample amount: 6 g Environmental temperature: 23 ° C. Humidity: 50% Cell inner diameter: 25 mm Cell temperature: 25 ° C. Spring wire diameter: 1.0 mm Compression speed: 0.1 mm / sec Compressive stress: 1 kg / cm ² Compression holding time: 60 seconds Tensile speed: 0.4 mm / sec

Note that the above bulk density and adhesive stress do not mean that they must be measured by the above-mentioned model, if they are determined by the same principle as above.

As the external additive, inorganic fine particles similar to those used to be added before the heat treatment, such as silica, titanium oxide, alumina, strontium zinc titanate, or organic fine particles can be used. 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight, is added to 100 parts by weight of the toner particles. These fine particles can be used even if the metal titanate having a relatively large diameter is not subjected to a hydrophobic treatment, but it is preferable that the surface is subjected to a hydrophobic treatment with a silane coupling agent or the like.

In particular, according to the present invention, the first inorganic fine particles having a sharp particle size distribution having a BET specific surface area of 100 m ² / g or more, and the first inorganic fine particles having a larger hydrophobic size than the inorganic fine particles. It is preferable to add the second inorganic fine particles. By doing so, it is easy to adjust the adhesion stress and the bulk density. When both large and small particles are added in this way, the amount of the large-diameter particles to be added is 0.2 to 5 parts by weight, preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the toner particles. Add 3 parts by weight.

The toner obtained as described above can be used in a one-component developing system in which the developing device passes a pressure contact portion between the toner regulating blade and the developing sleeve to charge the toner. Even if a two-component developing method in which the toner is charged by friction with the toner is adopted, the toner can be effectively used. Generally, the stress applied to the toner particles is greater in the one-component development system than in the two-component development system, so that the toner used in the one-component development system needs to have higher stress resistance than the toner used in the two-component development system. Is done. The method of development can be suitably used for both contact development and non-contact development.

The toner of the present invention is mainly composed of a binder resin having a high softening point, which is highly demanded in recent years and has high image quality, low consumption (color material high filling type), and is suitable for an energy saving fixing system. Even with the small particle size toner, the adhesion to the toner carrier (carrier, developing sleeve, developing roller, etc.), the photoconductor, and the transfer member is optimized and the mobility is excellent. In addition, the fluidity is excellent, the uniformity of charging is improved,
It has stable durability characteristics for a long time.

Referring to FIG. 3, a full-color image forming apparatus generally includes a photosensitive drum 1 which is rotationally driven in the direction of arrow a.
0, the laser scanning optical system 20, and the full-color developing device 3
0, an endless intermediate transfer belt 40 that is driven to rotate in the direction of arrow b, and a paper feed unit 60. Around the photosensitive drum 10, a charging brush 11 for charging the surface of the photosensitive drum 10 to a predetermined potential and a cleaner 12 having a cleaner blade 12a for removing toner remaining on the photosensitive drum 10 are further provided. is set up. In the present embodiment, in order to ensure the reliability of the cleaning performance of the spherical toner, an experiment was performed by changing to a cleaner using a brush cleaning method.

The laser scanning optical system 20 includes a laser diode, a polygon mirror, and an fθ optical element, and its control unit includes C (cyan), M (magenta),
Print data for each of Y (yellow) and Bk (black) is transferred from the host computer. The laser scanning optical system 20 sequentially outputs print data for each color as a laser beam, and scans and exposes the photosensitive drum 10. As a result, an electrostatic latent image for each color is sequentially formed on the photosensitive drum 10.

The full-color developing device 30 includes Y, M, C, and B
4 containing a one-component toner composed of k non-magnetic toners
The three color developing devices 31Y, 31M, 31C, and 31Bk are integrated, and can be rotated clockwise about the support shaft 81 as a fulcrum. Each developing device includes a developing sleeve 32 and a toner regulating blade 34. Developing sleeve 32
The toner conveyed by the rotation of the roller is charged by passing through a pressure contact portion (gap) between the blade 34 and the developing sleeve 32.

The positions of the developing devices for accommodating the yellow toner, magenta toner, cyan toner and black toner may be determined based on whether the full-color image forming apparatus is for the purpose of copying a line diagram image such as a character or a photograph. It depends on whether the purpose is to copy a shaded image of each color such as a picture, etc. For example, when the purpose is to copy a line diagram image such as a character, gloss (gloss) is used as a black toner. When using something that does not have
When the black toner layer is formed on the top of the full-color copy image, a sense of incongruity occurs. Therefore, it is preferable to load the black toner into the developing device so that the black toner layer is not formed on the top of the full-color copy image. In this case, it is most preferable that the black toner layer is formed on the intermediate transfer body at the time of primary transfer so that the black toner layer is formed on the lowermost position on the copy image. Will be loaded. At this time, the yellow toner, the magenta toner, and the cyan toner (color toner) may be arbitrarily loaded into the developing device so that the formation order of each layer in the primary transfer is any one of the first to third layers. .

The intermediate transfer belt 40 has support rollers 41 and 4
2 and endlessly stretched over the tension rollers 43 and 44, and are driven to rotate in the direction of arrow b in synchronization with the photosensitive drum 10. A projection (not shown) is provided on a side portion of the intermediate transfer belt 40. By detecting the projection by the microswitch 45, image forming processes such as exposure, development, and transfer are controlled. The intermediate transfer belt 40 is pressed by a rotatable primary transfer roller 46 and is in contact with the photosensitive drum 10. The contact portion is a primary transfer portion T _1. The intermediate transfer belt 40 is in contact with a rotatable secondary transfer roller 47 at a portion supported by the support roller 42. The contact portion is a secondary transfer portion T _2.

Further, a cleaner 50 is provided in a space between the developing device 30 and the intermediate transfer belt 40. The cleaner 50 has a blade 51 for removing residual toner on the intermediate transfer belt 40. The blade 51 and the secondary transfer roller 47 can contact and separate from the intermediate transfer belt 40.

The paper supply section 60 includes a paper supply tray 61 that can be opened to the front side of the image forming apparatus main body 1, a paper supply roller 62,
And a timing roller 63. The recording sheets S are stacked on a paper feed tray 61, fed one by one to the right in the drawing by the rotation of a paper feed roller 62, and synchronized with an image formed on the intermediate transfer belt 40 by a timing roller 63. To the secondary transfer section. The horizontal conveyance path 65 for the recording sheet is constituted by an air suction belt 66 and the like including the paper feeding section, and a vertical conveyance path 71 provided with conveyance rollers 72, 73, 74 from the fixing device 70 is provided. The recording sheet S is discharged from the vertical conveyance path 71 to the upper surface of the main body 1 of the image forming apparatus.

Here, the printing operation of the full-color image forming apparatus will be described. When the printing operation is started, the photosensitive drum 10 and the intermediate transfer belt 40 are driven to rotate at the same peripheral speed, and the photosensitive drum 10 is charged to a predetermined potential by the charging brush 11.

Subsequently, exposure of the cyan image is performed by the laser scanning optical system 20, and an electrostatic latent image of the cyan image is formed on the photosensitive drum 10. This electrostatic latent image is immediately developed by the developing device 31C, and the toner image is transferred onto the intermediate transfer belt 40 in the primary transfer section. Immediately after the completion of the primary transfer, the developing device 31M is switched to the developing unit D, and subsequently, exposure, development, and primary transfer of the magenta image are performed. Further, switching to the developing device 31Y, exposure, development, and primary transfer of the yellow image are performed. Further, the developing device 31
Switching to Bk, exposure and development of the black image, and primary transfer are performed, and the toner image is superimposed on the intermediate transfer belt 40 for each primary transfer.

When the final primary transfer is completed, the recording sheet S is sent to the secondary transfer section, and the full-color toner image formed on the intermediate transfer belt 40 is transferred onto the recording sheet S. When the secondary transfer is completed, the recording sheet S is conveyed to the belt-type contact heat fixing device 70, where the full-color toner image is fixed on the recording sheet S, and
Is discharged to the upper surface of the

Hereinafter, the present invention will be described with reference to examples.

[0091]

[Example of resin production]

In addition, PO is polyoxypropylene (2,2) -2,
2-bis (4-hydroxyphenyl) propane is EO
Represents polyoxyethylene (2,0) -2,2-bis (4
-Hydroxyphenyl) propane, TPA stands for terephthalic acid.

In a gas four-necked flask equipped with a thermometer, a stainless steel stirring rod, a falling condenser, and a nitrogen inlet tube, an alcohol component and an acid component were added in the above molar ratio to a polymerization initiator (dibutyltin oxide). Put in with. This was reacted in a mantle heater by heating under stirring and heating under a nitrogen stream.
The progress of the reaction was followed by measuring the acid value. The reaction was terminated when the acid value reached a predetermined value, and cooled to room temperature to obtain a polyester resin. Each of the obtained polyester resins crushed to 1 mm or less was used in the production of the following toner. The physical properties of the obtained polyester resin were as follows: number average molecular weight (Mn): 3300;
Weight average molecular weight (Mw) / number average molecular weight (Mn): 4.
2. Glass transition point (Tg): 68.5 ° C, softening point (T
m): 110.3 ° C., acid value: 3.3 KOH mg / g, and hydroxyl value: 28.1 KOH mg / g.

The above various physical properties were measured as follows.・ Measurement of glass transition point Tg of resin Differential scanning calorimeter (DSC-200: manufactured by Seiko Instruments Inc.)
Was used as a reference, alumina was used as a reference, and a 10 mg sample was measured at a heating rate of 10 ° C./min between 20 and 120 ° C., and the shoulder value of the main endothermic peak was taken as the glass transition point.

Measurement of softening point Tm of resin Using a flow tester (CFT-500: manufactured by Shimadzu Corporation), pores of a die (diameter 1 mm, length 1 mm), pressure 2
1 c under the conditions of 0 kg / cm ² and a heating rate of 6 ° C./min.
The softening point was defined as the temperature corresponding to 1/2 of the height from the outflow start point to the outflow end point when the m ³ sample was melted out.

Measurement of molecular weight The molecular weight was determined by gel permeation chromatography (80
7-IT type; manufactured by JASCO Corporation, and using tetrahydrofuran as a carrier solvent, the molecular weight was determined in terms of polystyrene.

Acid value The acid value was determined by dissolving 10 mg of a sample in 50 ml of toluene.
Using a mixed indicator of 0.1% bromthymol blue and phenol red, titrate with a pre-specified N / 10 potassium hydroxide / alcohol solution and calculate from the consumption of the N / 10 potassium hydroxide / alcohol solution. Value.

Hydroxyl value The hydroxyl value is the mg of potassium hydroxide required to treat a weighed sample with acetic anhydride, hydrolyze the resulting acetyl compound and neutralize liberated acetic acid. expressed.

(Examples of Production of Polyester Resins B and C)
Resins B and C were obtained in the same manner as in the production example of the polyester resin A, except that the molar ratio shown in Table 1 was changed to the alcohol component and the acid component.

[0099]

[Table 1]

[0100]

EXAMPLES Manufacture of Pigment Masterbatch The pigments used in the manufacture of full-color toners are thermoplastic resin and C.I. I. Pigm
ent Red 184 (manufactured by Dainippon Ink and Chemicals, Inc.) at a ratio of 7: 3 by weight in a pressure kneader.
Kneaded at 0 ° C. for 1 hour. After cooling, it was coarsely pulverized with a hammer mill to obtain a magenta pigment master batch having a pigment content of 30 wt%. Example of toner production

[Full Color Toner] Production Examples M-1 to M-2 Based on 90.7 parts by weight of the polyester resin A obtained in the resin production example, 13.3 parts by weight of a magenta master batch and salicylic acid as a charge control agent were used. Zinc complex (E-8)
4: 2.0 parts by weight of Orient Chemical Industry Co., Ltd. and 2.0 parts by weight of oxidized low molecular weight polypropylene (100TS: manufactured by Sanyo Chemical Co., Ltd .; softening point 140 ° C., acid value 3.5) were sufficiently mixed with a Henschel mixer. Then, a twin screw extruder (PC
(M-30; manufactured by Ikegai Iron Works Co., Ltd.), from which the discharge portion was removed, and the mixture was melt-kneaded and then cooled. The obtained kneaded material was rolled to a thickness of 2 mm with a cooling press roller, cooled with a cooling belt, and coarsely pulverized with a feather mill. Then, the average particle size was 10 to 10 with a mechanical grinder (KTM: manufactured by Kawasaki Heavy Industries, Ltd.).
Crushed to 12 μm, and then jet crusher (ID
S: manufactured by Nippon Pneumatic Industries, Ltd.) with an average particle size of 6.8 μm
m, and then the fine powder is classified using a rotor classifier (Teabrex classifier type: 100 ATP: manufactured by Hosokawa Micron Corporation) using a volume average particle size (Dt).
7.1 μm, weight% of twice or more (2D) of volume average particle size
Is 0.1% and the number% of 1/3 (D / 3) or less of the volume average particle diameter is 3.2% of magenta toner particles (M-
1) was obtained. The average circularity of the toner particles (M-1) was 0.943, and the standard deviation of the circularity was 0.039.

With respect to 100 parts by weight of the toner particles (M-1), 0.5 parts by weight of hydrophobic silica (TS-500: manufactured by Cabosil Co.) and hydrophobic silica (AEROSIL)
90G; manufactured by Nippon Aerosil Co., Ltd.) treated with hexamethylene disilazane; BET specific surface area 65 m ² / g, pH 6.
(Hydrophobic ratio: 96% or more), 1.0 part by weight was added, and the mixture was mixed by a Henschel mixer (peripheral speed: 40 m / sec, 60 seconds). After the modification, the yellow toner particles (M-
2) was obtained.

(Conditions for surface modification treatment) Developer supply section; Table feeder + vibratory feeder Dispersion nozzles; 4 nozzles (symmetrically arranged at 90 degrees with respect to the entire circumference) Ejection angle; 30 degrees Hot air volume; 800 L / Min dispersion air volume; 55 L / min suction air volume; -1200 L / min dispersion concentration; 100 g / m ³ treatment temperature; 250 ° C. residence time; 0.5 seconds cooling air temperature; 15 ° C. cooling water temperature;

The toner particles M-2 which have been subjected to the heat treatment as described above, when used later, have hydrophobic silica R97.
4 (manufactured by Nippon Aerosil Co., Ltd.) and 0.5 part by weight of strontium titanate particles were added to carry out a post-treatment, and used for later use. This post-treatment is applied to other toner particles unless otherwise specified.

Production Example M-3 to M-5 In the toner production example M-2, the temperature condition of the heat treatment was set to 1
Magenta toner particles (M-3 to M-5) by the same method and composition except that the temperature is changed to 50, 200 ° C., and 300 ° C.
I got

Production Example M-6 Toner particles M-6 were prepared in the same manner as in Production Example M-2 except that polyester resin B and resin C were blended at a ratio of 20:80. Obtained.

Production Example Magenta toner particles M-6 to M-
The production of No. 8 is omitted.

Production Example M-9 Based on 89.5 parts by weight of resin A, 15 parts by weight of magenta pigment masterbatch and compound

Embedded image 1 part by weight of a boron compound represented by
The colored resin solution was prepared by mixing and dissolving and dispersing parts by weight using an ultrasonic homogenizer (output: 400 μA) for 30 minutes.

On the other hand, an aqueous dispersion was prepared by dissolving 0.1 part by weight of sodium lauryl sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) in 1000 parts by weight of an aqueous solution containing 4% by weight of calcium phosphate as a dispersion stabilizer. It was adjusted. While stirring 100 parts by weight of the aqueous dispersion with a TK auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 50 rpm, 50 parts by weight of the colored resin solution is dropped, and the droplets of the colored resin solution are dispersed in an aqueous solution. It was suspended in the solution. This suspension is
The mixture was left for 5 hours at 100 ° C. and 100 mmHg to remove toluene from the droplets and precipitate colored resin particles. Then, after dissolving calcium hydroxide phosphate with concentrated sulfuric acid, filtration and washing with water were repeated. Thereafter, the colorant particles were dried at 75 ° C. by a slurry drying device (Dispercoat: manufactured by Nisshin Engineering Co., Ltd.).
A magenta toner (M-9) was obtained.

Production Example M-10 1.0 part by weight of hydrophobic silica (RX200; manufactured by Nippon Aerosil Co., Ltd .; BET specific surface area 140 m ² / g, pH 7.0) per 100 parts by weight of toner particles (M-1) And a Henschel mixer (peripheral speed 40 m / sec, 18
After the mixing treatment (for 0 seconds), the surface was modified by heat under the following conditions using an instant heating device having the configuration shown in FIG. 1 to obtain magenta toner particles (M-10).

(Conditions for surface modification treatment) Developer supply section; Table feeder Dispersion nozzles; 2 (symmetrical arrangement with respect to the entire circumference) Ejection angle: 45 degrees Hot air volume; 620 L / min Dispersed air volume: 68 L / min Suction air volume; -900 L / min Dispersion concentration; 150 g / m ³ Processing temperature; 250 ° C Residence time; 0.5 seconds Cooling air temperature; 30 ° C Cooling water temperature;

Production Examples M-11 to M-13 The magenta toner particles (M) were prepared in the same manner and composition as in Production Example M-10 except that the temperature conditions for the heat treatment were changed to 150, 200 ° C. and 300 ° C. -11 to M-
13) was obtained.

Production Example M-14 In the production example M-2 of the toner, 0.5 parts by weight of hydrophobic silica TS-500 and hydrophobic silica AE were added under the pretreatment conditions.
M-2 except that 0.5 parts by weight of ROSIL90G is used.
In the same manner as in the production method, toner particles M-14 were obtained.

Production Example M-15 The same procedure as in Production Example M-14 of Toner except that 0.5 parts by weight of hydrophobic silica TS-500 and 0.5 parts by weight of strontium titanate particles were used for the post-treatment. In the same manner as in the production method No. 14, toner particles M-15 were obtained.

Production Example M-16 In the production example M-2 of the toner, the heat treatment temperature was set to 180 ° C.
Except that the toner particles M-
16 was obtained.

For the toner obtained as described above, pretreatment conditions, heat treatment conditions, treatment temperatures, post-treatment conditions,
Average circularity, circularity standard deviation (SD), toner volume average particle diameter (Dt) (μm), content ratio of particles more than twice the volume average particle diameter (> 2D (wt%)), volume average particle diameter 1 /
Tables 2 and 3 summarize the content ratio of particles of 3 or less (<１ ／ Dpop%), toner surface shape (D / d50), specific surface area (S), true density, bulk density / true density, and adhesion stress. Was.

The average particle size and its distribution were measured using a Coulter Multisizer II (manufactured by Coulter Counter) with an aperture tube diameter of 50 μm. The particle size of the carrier was measured using a Coulter Multisizer II (manufactured by Coulter Counter) with an aperture tube diameter of 150 μm.

The average circularity and SD value were measured in an aqueous dispersion system using a flow type particle image analyzer (FPIA-2000: manufactured by Toa Medical Electronics Co., Ltd.).

The BET specific surface area (S) required for calculating D / d50 was measured using Flowsorb Model 2300 (manufactured by Shimadzu Corporation). The relative weight distribution by particle size was measured using a Coulter Multisizer: manufactured by Coulter Counter.

The true density was measured using an air comparison specific gravity meter (manufactured by Beckman).

The bulk density and the adhesive stress were measured using an Agrobot (manufactured by Hosokawa Micron Corporation).

[0122]

[Table 2]

[0123]

[Table 3]

The magenta toner obtained as described above was modified by using a printer Color Page Pro (PS; manufactured by Minolta) having a configuration shown in FIG. Followability, fog and poor regulation were assessed.

(Fog) The magenta toner was set in a developing device, and after 10 sheets were printed in a HH environment (30 ° C., 85%) at a C / W ratio of 5% (initial), white development (blank paper mode) was performed.
Paper is fed and stopped halfway. After stopping, remove the developing unit from the printer, observe the photoreceptor fog,
The ranking was as follows. NN environment (23 ℃,
After printing 5000 (5K) sheets under 50%), the same evaluation was performed.

：: Fog hardly occurred; Δ: Slight fog occurred but no practical problem; ×: Fog occurred.

(Defective regulation) A magenta toner is loaded in a developing device, and an image having a C / W ratio of 5% is converted to an HH environment (30 ° C., 85%).
Below, 10 sheets were printed, and the thin toner layer on the sleeve was visually observed and ranked as follows. When the blade is fixed, streaks occur in the thin toner layer on the sleeve. In addition, 50% under NN environment (23 ° C, 50%)
00 (5K) sheets were printed, similarly observed and ranked. ：: no streak was generated; Δ: slight streak was generated, but there was no practical problem; ×: streak was significantly generated.

(Followability) A magenta toner is loaded in a developing device, and an image having a C / W ratio of 30% is converted to an HH environment (30 ° C., 85%).
After printing 10 sheets below, an image having a C / W ratio of 100% was printed, and the unevenness of the dark layer was evaluated. Also N
1000 sheets and 500 sheets under N environment (23 ° C, 50%)
0 sheets were printed and evaluated in the same manner. When the toner thin layer unevenness occurs, density unevenness occurs on the image. ：: No density unevenness occurred. Δ: Although density unevenness occurred slightly, there was no practical problem. D: Density unevenness has occurred, and there is a problem in practical use.

Table 4 summarizes the above results.

[Table 4]

[0130]

According to the present invention, the toner obtained by the kneading-pulverization method has a surface property in which pores on the surface are reduced and the smoothness is excellent. As a result, unevenness of dark layer, fogging and defective regulation do not occur, uniform charging and excellent image performance can be achieved, and stable image performance can be achieved for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for performing an instantaneous heat treatment.

FIG. 2 is a schematic horizontal sectional view of a sample ejection chamber in the apparatus of FIG.

FIG. 3 is a schematic configuration diagram of a one-component full-color image forming apparatus.

[Explanation of symbols]

 101: Hot air generators 102, 102 ', 102 ": Introducing tube 103: Sample injection nozzle 104: Retained powder 105: Toner particles 106: Hot air injection nozzle 107: Injection chamber 108: Cooling air inlet 109: Cyclone 111: Product tank 112: Bag filter 113: Blower

Continued on the front page (72) Inventor Masahiro Anno 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Tsutsui Main Tax 2-chome Azuchicho, Chuo-ku, Osaka-shi, Osaka No. 13 Osaka International Building Minolta Co., Ltd. (72) Inventor Hiroyuki Fukuda 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Osaka International Building Minolta Co., Ltd.

Claims (1)

[Claims] 1. The surface condition is represented by the following conditional expression [I]: D / d50 ≧ 0.40, where D = 6 / (ρ · S) [I] (where D is assumed to be a spherical shape of the toner) Converted particle size from the BET specific surface area at the time (μm); d50 is 50% relative particle size (μm) of relative weight distribution by particle size; ρ is true density (g / c)
m ³ ); S represents a BET specific surface area (m ² / g), respectively. Non-magnetic toner characterized in that (bulk density / true density (ρ) when compressed at 1 kg / cm ² ) × 100 ≧ 45; and adhesion stress at 1 kg / cm ² compression satisfies 6 g / cm ² or less. .