JP2000098668A - Image forming method and developer for replenishment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming method in which contamination of a carrier is prevented and with which high quality images without image defects such as fog but with good reproducibility of fine lines and gradation can be formed. SOLUTION: A developing device equipped with a developer tank to house a developer consisting of a toner and carrier, a toner supplying means to supply a toner a the developer tank, a carrier supplying means to supply the carrier to the developer tank, and a discharging means to discharge the developer from the developer tank is used. The image forming method includes a process to develop electrostatic latent images formed on an electrostatic latent image holding body with a toner to form a toner image and a process to transfer the toner image to a transfer material. In this method, the toner consists at least of a binder resin and color particles containing a coloring agent. The volume average particle size of the color particles ranges from 1.0 to 5.0 μm, the proportion of color particles of <=1.0 μm particle size is <=20 number % and that of color particles over 5.0 μm particle size is <=10 number %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method used in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc., and more particularly, to developing an electrostatic latent image using a developing trickle system. The present invention relates to an image forming method and a replenishing developer used in the image forming method.

[0002]

2. Description of the Related Art In electrophotography, a toner in a developer is adhered to an electrostatic latent image formed on a photoreceptor, transferred onto paper or a plastic film as a transfer material, and then fixed by heating or the like. Form an image. The developer used here includes a two-component developer composed of a toner and a carrier, and a one-component developer such as a magnetic toner. It has features such as good controllability for sharing functions, and is currently widely used.

On the other hand, printers and copiers using electrophotography have been increasingly colorized in recent years, and electrostatic latent images have become finer due to improvements in the resolution of apparatuses. Along with this, the toner diameter has been reduced in recent years in order to faithfully develop the electrostatic latent image and obtain a higher quality image. In particular, a full-color copying machine that develops, transfers, and fixes a digital latent image with a chromatic toner achieves a certain high image quality by using a small particle size toner of 7 to 8 μm.

A variety of toners having a defined particle size have been proposed for the purpose of improving image quality. For example, Japanese Unexamined Patent Publication (Kokai) No. 58-129439 proposes a non-magnetic toner having an average particle diameter of 6 to 10 μm and a maximum number of particles of 5 to 8 μm. However, since the toner has as few as 15% by number of particles having a particle size of 5 μm or less, using this toner tends to form an image lacking sharpness. JP-A-7-146589 proposes a color toner having a weight average particle diameter of 3 to 7 μm and containing 10 to 70% by number of particles having a particle diameter of 4 μm or less. However, this toner has few particles having a particle size of 4 μm or less necessary for high image quality, and has a particle size of 8 μm.
Since the above particles are 2 to 20% by volume, 8 μm which causes image quality deterioration such as toner scattering at the image edge portion.
If the content of the above particles is too large, the effect of improving the image quality of the image by reducing the particle size of the toner is impaired. Further, Japanese Patent Application Laid-Open No. 9-222799 proposes a toner having a volume average particle diameter of 4 μm or less, but does not disclose a particle size distribution of toner particles which is important for high image quality.

[0005]

On the other hand, in a two-component developer, as the particle size of the toner is reduced, carrier contamination becomes remarkable. In a two-component developer, both the carrier and the toner are agitated in the developing device, but while the toner is consumed by the development, the carrier is not consumed and remains in the developing device, and is repeated in the developing device. Stirred. As a result, the carrier surface is contaminated by a part of the toner or a part of the external additive, and the charging performance as a developer gradually decreases. For this reason, image quality defects such as a decrease in image density and fogging occur, which causes a decrease in image quality. Since the small particle size toner has a large non-electrostatic adhesive force and a tendency to decrease the powder fluidity, it is necessary to add a large amount of an external additive. Therefore, when a small particle size toner is used, carrier contamination by the toner and external additives tends to be promoted.

The present invention can prevent image quality defects such as fogging over time due to carrier contamination, and can form a high quality image with good fine line reproducibility and gradation reproducibility without image quality defects such as fog. It is an object to provide an image forming method. Another object of the present invention is to provide an image forming method capable of stably forming a high-quality image of single color and multicolor. Still another object of the present invention is to provide a replenishing developer used in the image forming method.

[0007]

According to a first aspect of the present invention, there is provided a developer tank for storing a developer comprising a toner and a carrier, a toner replenishing means for replenishing the developer tank with a toner, and a carrier replenishing the developer tank. Developing the electrostatic latent image formed on the electrostatic latent image carrier with toner using a developing device having a carrier replenishing unit for replenishing the toner and a discharging unit for discharging the developer from the developer tank; An image forming method including a developing step of forming an image and a transfer step of transferring the toner image to a transfer material, wherein the toner comprises colored particles containing at least a binder resin and a colorant, and The volume average particle size of the colored particles is 1.0 to 5.0 μm, and 1.0 μm
The image forming method is characterized in that the following colored particles are 20% by number or less, and the colored particles exceeding 5.0 μm are 10% by number or less. It is preferable that the toner and the carrier are replenished so that the replenishment amount is 1: 1 to 30: 1 in weight ratio per unit time.

According to a second aspect of the present invention, there is provided a developer tank for storing a developer including a toner and a carrier, a replenishing means for replenishing the developer tank with a replenishing developer including a toner and a carrier, and a developer tank. Developing a latent image formed on an electrostatic latent image carrier with toner using a developing device having a discharging unit that discharges a developer from the developing device, and forming the toner image And transferring the toner to a transfer material, wherein the toner comprises colored particles containing at least a binder resin and a colorant, and the volume average particle size of the colored particles is 1.0. An image forming method is characterized in that the number of colored particles having a particle size of 1.0 to 5.0 μm is 20% by number or less, and the number of colored particles exceeding 5.0 μm is 10% by number or less. It is preferable that the replenishing developer contains the toner and the carrier in a weight ratio of 1: 1 to 30: 1.

In the first and second inventions, the charge amount of the toner under the environment of a temperature of 20 ° C. and a humidity of 50% is represented by q
(FC), where the particle diameter of the toner is represented by d (μm),
It is preferable that the peak value in the frequency distribution of the q / d value of the toner in the developer tank is 1.0 or less and the bottom value is 0.005 or more.

Further, an external additive may be further added to the toner, wherein (a) the external additive comprises at least 30 n
at least one kind of ultrafine particles having an average primary particle diameter of not less than m and not more than 200 nm, and at least one kind of ultrafine particles having an average primary particle diameter of not less than 5 nm and less than 30 nm,
(B) The coverage of the external additive on the surface of the colored particles determined by the following equation (1) is 20% or more for both the ultrafine particles Fa and the ultrafine particles Fb, and the total coverage of all the external additives is It is preferably 100% or less. F = √3 · D · ρ _t (2π · d · ρ _a ) ⁻¹ · C × 100 (1) (where F is the coverage (%) and D is the volume average of the colored particles. Particle size (μm), ρ _t is the true specific gravity of the colored particles, d is the average primary particle size of the external additive (μm), ρ _a is the true specific gravity of the external additive,
And C are the weight of the external additive x (g) and the weight of the colored particles y
(G) and the ratio (x / y). )

The colorant is preferably pigment particles, and the concentration of the colorant in the color particles is C (% by weight);
When the true specific gravity of the colored particles is a (g / cm ³ ) and the volume average particle size of the colored particles is D (μm), it is preferable that the following expression (2) is satisfied. 25 ≦ a · D · C ≦ 90 (2)

According to a third aspect of the present invention, there is provided a replenishing developer in which a toner and a carrier having the above characteristics are mixed in a ratio of 1: 1 to 30: 1.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The image forming method of the present invention will be described with reference to embodiments. 1. Developing Step In the image forming method of the present invention, in the developing step, a so-called trickle developing device is used to develop the electrostatic latent image formed on the electrostatic latent image carrier to form a toner image. Features. The trickle method replaces the deteriorated developer with new developer by replenishing the developer tank with toner and carrier separately or simultaneously, and discharging excess developer from the developer tank. A method for maintaining the developing characteristics of the developer therein.
As the developing device used in the present invention, a known trickle developing device can be used without limitation. In order to facilitate the description of the invention, a trickle type developing device will be described below with reference to the drawings. However, the drawings are used only for this purpose, and the developing device used in the present invention is not limited to this. is not.

FIGS. 2 to 5 show a trickle developing apparatus A having means for supplying toner to the developer tank, means for supplying carrier to the developer tank, and means for discharging the developer from the developer tank. 1 shows a schematic cross-sectional view of an example. The developing step of the image forming method of the present invention will be described below with reference to FIG. The developing device A includes a supply tank 111 for storing toner.
And a replenishing tank 112 for storing the carrier, and a developer discharging tank 113 for discharging the deteriorated developer. Dispensing members 114 and 115 for supplying toner or carrier to the developer tank 110 are provided in each of the supply tank 111 and the supply tank 112.
Each of the dispensing members 114 and 115 is driven according to the amount of consumed toner or the driving time of the developing device A, and adjusts the amount of toner or carrier supplied into the developer tank 110.

First, as shown in FIG.
When the toner dispense 114 contained therein is driven according to the consumption amount of the developer (toner consumption amount), the toner is supplied from the toner supply tank 111 to the developer tank 110 through the toner supply port 116. On the other hand, the carrier supply tank 112 is provided with a carrier dispense 115. As shown in FIG.
5 is driven in accordance with the toner consumption, the developer tank 1 is passed from the carrier supply tank 112 through the carrier supply port 117.
10 is supplied with a carrier.

In the present invention, the developer in the developer tank has a mixing ratio of toner and carrier of 1: 100 to 1: 100 by weight.
When the ratio is maintained in the range of 20: 100, the toner can be charged efficiently.
0-15: 100, more preferably 3: 100.
The range is from 10 to 100. The ratio of the replenishment amounts of the toner and the carrier is determined so that the mixing ratio of the toner and the carrier in the developer tank is maintained in the above range. The ratio of the replenishment amounts of the toner and the carrier is preferably set to 1: 1 to 30: 1 in weight ratio per unit time,
It is more preferable that the ratio be 2: 1 to 20: 1.

When toner and carrier are supplied to the developer tank 110 and the volume of the developer in the developer tank 110 increases, the developer (deteriorated developer) in the developer tank 110 is discharged from the developer discharge port 118. The deteriorated developer overflows to the developer discharge tank 113 and is discharged by the replenished amount of the toner and the carrier. In addition, the developer discharging means includes, for example, a shutter provided between the developer tank and the developer discharging tank, and opens and closes the shutter according to the amount of the replenished toner and carrier to discharge the deteriorated developer. It may have a mechanism for adjusting the amount. Further, a pickup member may be provided in the developer tank, and the pickup member may be driven in accordance with the replenishment amounts of the toner and the carrier to move the deteriorated developer from the developer tank to the developer discharge tank.

In order to prevent the newly replenished toner and carrier from being discharged immediately, it is preferable to provide a conveying member in the developer tank to direct the movement of the developer. For example, in the developing device shown in FIGS. 2 to 4, two augers 119 are provided in the developer tank 120 so that the developer circulates in a direction indicated by a solid line arrow in FIG. 5. When the volume of the developer increases, the developer is discharged to the developer discharge tank 113 in the direction of the dashed arrow in FIG. In addition, a stirring member may be provided in the developer tank so that the replenished toner and the carrier are sufficiently stirred.

FIG. 6 is a schematic cross-sectional view of an example of a trickle type developing device including a means for replenishing a developer tank with a replenishing developer composed of toner and carrier, and a means for discharging the developer from the developer tank. The figure is shown. The same members as those of the developing device A are denoted by the same reference numerals, and the description is omitted. The developing device B includes a replenishing tank 131 for replenishing developer composed of toner and carrier, and a developer discharging tank 113 for discharging the deteriorated developer. The replenishing tank 131 is provided with a dispense member 134 for replenishing the replenishing developer to the developer tank. The dispensing member 134
It is driven in accordance with the consumption amount of toner or the driving time of the developing device B, and adjusts the replenishment amount of the replenishing developer into the developer tank.

In the developing device of this aspect, the preferable range of the mixing ratio of the toner and the carrier in the developer tank is the same as the above range. The mixing ratio of the toner and the carrier contained in the replenishing developer is determined so that the mixing ratio of the toner and the carrier in the developer tank is within the above range. The mixing ratio of the toner and the carrier contained in the replenishing developer is preferably from 1: 1 to 30: 1 by weight,
It is more preferable that the ratio be 2: 1 to 20: 1.

In the developing device A and the developing device B, the developer in the developer tank is rotatably supported via a paddle roller 120 (developer supply member).
21 surface. The developing roll 121 includes a magnetic roll 122 and a developing sleeve 123. Due to the magnetic force of the magnetic roll 122, the developer supplied to the surface of the developing roll 121 forms a magnetic brush. A blade 124 is in contact with the surface of the developing roll 121 to regulate the thickness of the developer layer (toner layer). On the other hand, an electrostatic latent image carrier (not shown) such as a photoconductor is rotatably disposed so as to face the developing roll 121 at a position opposite to the developer tank. As both the electrostatic latent image carrier and the developing roll 121 rotate, the magnetic brush rubs the surface of the electrostatic latent image carrier, and as a result, the electrostatic latent image on the electrostatic latent image carrier becomes Developed to form a toner image.

As the amount of toner used for developing the electrostatic latent image is reduced, the thickness of the toner image can be reduced, and the deterioration of image quality due to the subsequent electrostatic transfer can be reduced. Further, since the image step after fixing can be reduced, it is possible to reduce the deterioration of the image quality due to the image step in the image and in the image portion / non-image portion. When a multicolor image is formed, for example, a developing device that stores developers having various hues (for example, cyan, magenta, yellow, and black) is used to convert the electrostatic latent image of each hue. A multicolor image is formed by repeatedly developing with a developer and superimposing each single color toner image. Therefore, particularly when a multicolor image is formed, the thickness of the image tends to be extremely large. The small particle size toner used in the present invention can develop an electrostatic latent image with a small amount of toner. The amount of toner (DMA) used for development varies depending on the area ratio of the image. However, when an image having an area ratio of 100% is formed, it is preferably 0.5 mg / cm ² or less for a single color. More preferably, it is not more than 0.41 mg / cm ² . On the other hand, in order to form a toner image having a sufficient color density, the amount of toner used for development is preferably 0.11 mg / cm ² or more.
More preferably, it is 0.16 mg / cm ² or more.

2. Transfer Step The toner image formed on the electrostatic latent image carrier is conveyed to a position facing a transfer member such as a transfer roll by rotation of the photoconductor, and is transferred to a transfer material such as recording paper. Further, an intermediate transfer member may be provided, and the toner image formed on the electrostatic latent image carrier may be temporarily transferred to the intermediate transfer member, and then transferred to recording paper or the like.

When the transfer efficiency from the electrostatic latent image carrier to the transfer material is 100%, the DMA and the toner amount (TMA) of the toner image transferred onto the transfer material have the same value.
Usually, the transfer efficiency is slightly lower than 100%.
A is smaller than DMA. To form a good image that does not give the observer a visual discomfort due to the image thickness, TM
A (when forming an image having an area ratio of 100%) is preferably 049 mg / cm ² or less for a single color,
g / cm ² or less is particularly preferred. On the other hand, in order to form a toner image having a sufficient color density, TM
A is preferably 0.10 mg / cm ² or more,
More preferably, it is 0.15 mg / cm ² or more.

3. Outline of Image Forming Method FIG. 1 shows a schematic cross-sectional view of an example of an image forming apparatus using the image forming method of the present invention. The photoconductor 1 is uniformly charged by the charger 2. Next, the photoconductor 1 is illuminated imagewise by the laser 3 to form an electrostatic latent image on the photoconductor 1. The electrostatic latent image on the photoconductor 1 is transported to a position facing the developing roll 21 built in the trickle type developing device A as the photoconductor rotates. At this position, the electrostatic latent image is developed by the trickle type developing device A, and a toner image is formed on the photoconductor 1. The toner image is conveyed to a position facing the transfer charger 5 by rotation of the photoconductor 1, and is transferred to a transfer material. The transfer image transferred to the transfer material is fixed to the transfer material by a fixing roll (not shown) as required, and an image is formed on the transfer material. On the other hand, the photoconductor 1 comes into contact with the cleaner 6, and the toner remaining on the photoconductor 1 is removed by the cleaner 6. Thereafter, the image is charged by the charger 2 and a series of image forming steps is repeated.

4. Developer The developer used in the present invention comprises a toner and a carrier. In the present invention, the particle size and the particle size distribution of the colored particles constituting the toner are restricted to a certain range, thereby improving the fine line reproducibility and gradation of the image.

5. Toner The toner used in the present invention comprises colored particles containing at least a binder resin and a colorant, and the volume average particle size of the colored particles is 1.0 to 5.0 μm.
m is 20% by number or less, and 5.0 μm
The number of colored particles exceeding 10% is not more than 10% by number.

5.1 Particle Size and Particle Size Distribution of Colored Particles The toner used in the present invention is a small particle size toner in which the volume average particle size of the contained colored particles is in the range of 1.0 to 5.0 μm. Therefore, the formed image has high fine line reproducibility and high gradation reproducibility. Further, the volume average particle size of the colored particles is in the range of 2.0 to 5.0 μm, and more preferably 2.0 to 4.5 μm.
It is more preferably in the range of μm, more preferably in the range of 2.0 to 4.0 μm. The volume average particle size of the colored particles is 5.0
When the particle size is not more than μm, the ratio of coarse particles is small, so that the reproducibility of fine lines and minute dots of an image and the reproducibility of gradation are improved. On the other hand, when the volume average particle diameter of the colored particles is less than 1.0 μm, the powder fluidity, developability, or transferability of the toner composed of such colored particles is deteriorated, and the surface of the electrostatic latent image carrier is deteriorated. The above range is preferable because various problems may occur, such as deterioration in the cleaning performance of the remaining toner. In the present invention, "reproducibility of fine lines"
It mainly means whether or not a fine line having a width of 30 to 60 μm, preferably 30 to 40 μm can be faithfully reproduced, and further, it is taken into consideration whether or not a dot having the same diameter can be reproduced.

The colored particles have a particle size distribution of not more than 20% by number of colored particles of 1.0 μm or less and not more than 10% by number of colored particles of not less than 5 μm. If the number of colored particles having a size of 1.0 μm or less in all the colored particles exceeds 20% by number, fogging in the non-image area is apt to occur, and poor cleaning of the photoconductor is liable to occur. When the number of colored particles of 1 μm exceeds 20% by number, such a fine particle toner tends to adhere to the carrier surface, and the ability of the carrier to impart charge to the toner and the resistance tend to increase. However, the image quality of the obtained image may be degraded. From the viewpoint of achieving high image quality and maintaining high image quality, 1.0
It is more preferable to show a particle size distribution in which the colored particles of μm to 2.5 μm are 5 to 50% by number.

Although the number% of colored particles exceeding 5.0 μm was used as a parameter for defining the large particle size side of the particle size distribution of the colored particles, the standard particle size may be defined by other numerical values. it can. Specifically, when 4.0 μm is set as the standard particle size, it is preferable that 75% by number or more of the colored particles of 4.0 μm or less among all the colored particles.

The colored particles having such a particle size distribution can be produced by a conventionally known production method. For example, when obtaining by a pulverization method, the conditions of pulverization and classification may be appropriately set, and when obtaining by a polymerization method (suspension polymerization method, emulsion polymerization method or the like), granulation conditions at the time of polymerization may be appropriately set. In the pulverization method, after preliminarily mixing a binder resin, a colorant, and other additives as necessary, the mixture is melt-kneaded in a kneader, cooled, pulverized and classified to make the particle size distribution uniform. Conventionally, in the grinding method,
When the colored particles are reduced in size, problems such as an increase in cost due to a decrease in pulverizability and a decrease in classifying properties due to deterioration of powder characteristics may occur. When the colored particles used in the present invention are produced by a pulverization method, if the pulverization conditions are appropriately selected and set at the time of pulverization, without accompanying broadening of the particle size distribution due to over-pulverization, the preferable particle size distribution range. Colored particles exhibiting a close particle size distribution can be produced. Therefore, thereafter, there is little need to adjust the particle size distribution using a classifier, or even if there is a need to adjust the particle size distribution, the amount of the colored particles to be removed is very small, so the manufacturing cost is reduced. Can be lower.

The particle size distribution of the colored particles can be measured by various methods. In the present invention, the particle size distribution of the colored particles is measured using a Coulter Counter TA2 type (manufactured by Coulter Inc.) with an aperture diameter of 50 μm. 1μ
This is a particle size distribution measured by setting the aperture diameter to 30 μm only when measuring the number distribution of colored particles of m or less. Specifically, the particle size distribution was measured using an aqueous sodium chloride solution (1
0 g / l) (surfactant: Triton X)
100) Two to three drops and a measurement sample (colored particles) are added, and a dispersion treatment is performed for 1 minute by an ultrasonic disperser, and then the above-described apparatus is used.

5.2 Colorant Pigment particles are preferably used as the colorant contained in the color particles. Pigment particles have high coloring power, and are excellent in water resistance, light resistance, or solvent resistance.Therefore, if pigment particles are used as a coloring agent, even if the weight of the toner per unit area of an image is reduced, it is sufficient. This is preferable because a high image density can be achieved, and the water resistance, light resistance, or solvent resistance of the image can be ensured.

Examples of usable pigments include carbon black, nigrosine, graphite, C.I. I. Pigment Red 48: 1, 48: 2, 48: 3, 53: 1, 57: 1,
112, 122, 123, 5, 139, 144, 14
9, 166, 177, 178, 222, C.I. I. Pigment Met Yellow 12, 14, 17, 97, 180, 18
8, 93, 94, 138, 174, C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I.
I. Pigment Blue 15: 3, 15, 15: 2, 6
0, C.I. I. Pigment Green 7 and the like. Among them, carbon black, C.I. I. Pigment Red 48: 1, 48: 2, 48: 3, 53: 1, 5
7: 1, 112, 122, 123, C.I. I. Pigment Met Yellow 12, 14, 17, 97, 180, 188,
C. I. Pigment Blue 15: 3 is preferred. These pigments can be used alone or in combination of two or more.

When the dispersion particle size of the colorant contained in the color particles is reduced, the transparency of the toner is improved. For example, when forming a full-color image, a single-color toner image is superimposed, but if the transparency of the colored particles is low,
When expressing a secondary color such as red or green or a tertiary color such as process black, the color development of the lower layer is alienated by the colored particles of the upper layer, and good color reproduction may not be performed. By reducing the dispersed particle diameter of the colorant contained in the colored particles, the transparency of the toner can be ensured, and the occurrence of such a phenomenon can be suppressed. The dispersion particle diameter range of the colorant suitable for securing the transparency of the toner is different depending on the type of the colorant used.For example, when pigment particles are used as the colorant, the dispersion Pigment particles dispersed in a state where the particle average particle diameter is 0.3 μm or less in circle equivalent diameter are preferred.

In the present invention, the circle-equivalent diameter of the average particle size of the dispersed pigment particles in the binder resin is defined as the diameter of a part of the colored particles taken out, embedded in the resin, and dispersed in the colored particles. A slice for observation was cut out so that the state could be observed, a magnified photograph of 15,000 times magnification was taken with a transmission electron microscope, the area of pigment particles was measured with an image analyzer, and the diameter of a circle corresponding to the area was measured Means the value calculated.

As a method for dispersing the pigment particles in the binder resin, for example, there is a melt flushing method proposed by the present inventors (Japanese Patent Laid-Open No. 4-22752). The melt flushing method referred to here is one of the methods for dispersing pigment particles in a binder resin, and for a water-containing pigment cake produced in a pigment manufacturing process, the water contained in the cake is melted and bound. This is a method of replacing with a resin. According to this method, the average particle size of the dispersed particles of the pigment particles in the binder resin can be made equal to or less than 0.3 μm in circle equivalent diameter. As a result, the color density of the toner can be extremely effectively improved. When a toner having a small pigment dispersed particle diameter is used as described above, transparency of the toner can be ensured and color reproducibility is improved, so that it is suitable for forming a multicolor image.

When the content of the coloring agent in the colored particles is increased, the color density per unit weight of the colored particles is increased, and D
MA can be reduced. As a result, the amount of toner consumed in the image forming process can be reduced, so that the cost can be reduced and the contamination of the carrier can be further suppressed, which is preferable. Further, by reducing the number of DMAs, the image quality of an image can be further improved. The concentration of the colorant in the colored particles varies depending on the type of the colorant used. For example, when pigment particles are used as the colorant, the concentration C (%) of the pigment particles in the colored particles is:
It is preferable that the following relational expression (2) is satisfied. 25 ≦ a · D · C ≦ 90 (2) In the relational expression (2), D is the volume average particle diameter of the colored particles (unit:
μm), and a is the true specific gravity of the colored particles (unit: g / cm)
³ ).

If the value of aDC (hereinafter abbreviated as "aDC") is less than 25, the color density per unit weight of the toner tends to be insufficient. On the other hand, as the value of aDC increases, the color density of the toner increases.
If it exceeds 0, even when a very small amount of toner scatters to the non-image area, the background stain may become remarkable, or the melt viscosity of the colored particles may increase due to the reinforcing effect of the pigment, and the fixability may decrease.

The preferred concentration of the pigment particles in the colored particles also depends on the coloring power of the pigment particles. For example,
When pigment particles having relatively strong coloring power such as black and cyan are used, the upper limit of aDC is more preferably 60. However, this is only a guide and even if pigments of the same color have different coloring powers due to differences in chemical structural formulas and the like, the pigment concentration may be appropriately set according to the type of pigment used.

5.3 Binder Resin The binder resin contained in the colored particles has a glass transition point of 50.
To 80 ° C., more preferably 55 to 80 ° C.
75 ° C. When the glass transition point is lower than 50 ° C., the heat storage property is reduced, and when it is higher than 80 ° C., the low-temperature fixability is lowered, which is not preferable.

The softening point of the binder resin is 80 to 1
The temperature is preferably 50 ° C, more preferably 90 to 1 ° C.
The temperature is 50 ° C, more preferably 100 to 140 ° C. When the softening point is less than 80 ° C, the heat storage property is reduced, and the
If the ratio exceeds, the low-temperature fixability is lowered, so that each is not preferred. Further, the number average molecular weight of the binder resin is 1.0
The range of × 10 ^{3 to} 5.0 × 10 ⁴ and the weight average molecular weight of 7.0 × 10 ^{3 to} 5.0 × 10 ⁵ are preferable.

As the binder resin, those conventionally used as toner binder resins are used without any particular limitation. Styrene-based polymers, (meth) acrylate-based polymers, and styrene- (meth) acrylic As the acid ester polymer, one selected from the following styrene monomers, (meth) acrylate monomers, other acrylic or methacrylic monomers, vinyl ether monomers, vinyl ketone monomers, N-vinyl compound monomers, etc. Alternatively, a polymer obtained by polymerizing two or more monomers is suitably used.

Examples of the styrene monomer include styrene, o-methylstyrene, ethylstyrene, p-methoxystyrene, p-phenylstyrene, 2,4-dimethylstyrene, pn-octylstyrene, and pn-decylstyrene. And styrene derivatives such as pn-dodecylstyrene and butylstyrene.

Examples of (meth) acrylate monomers include, for example, methyl (meth) acrylate and (meth) acrylate.
Ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, n-octyl (meth) acrylate, dodecyl (meth) acrylate, (meth) acrylic acid-2- (Meth) acrylates such as ethylhexyl, stearyl (meth) acrylate, phenyl (meth) acrylate, and dimethylaminoethyl (meth) acrylate; and the like.

Other acrylic or methacrylic monomers include, for example, acrylonitrile, methacrylamide, glycidyl methacrylate, N-methylol acrylamide, N-methylol methacrylamide,
-Hydroxyethyl acrylate and the like.

Examples of the vinyl ether monomer include vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether.

Examples of vinyl ketone monomers include vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone.

Examples of the N-vinyl compound monomer include N-vinyl compounds such as N-vinyl pyrrolidone, N-vinyl carbazole and N-vinyl indole.

In the present invention, polyester is preferably used as a binder resin from the viewpoint of fixability. As such a polyester, those synthesized by polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol can be used.

The polyhydric alcohol monomers include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, 1,5-pentanediol, 1,6- Aliphatic alcohols such as hexanediol and neopentyl glycol; alicyclic alcohols such as cyclohexanedimethanol and hydrogenated bisphenol; bisphenols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct.
Derivatives and polyvalent carboxylic acids such as phthalic acid, terephthalic acid, aromatic carboxylic acids such as phthalic anhydride and their acid anhydrides, succinic acid, adipic acid, sebacic acid, azelaic acid, saturated and unsaturated such as dodecenyl succinic acid Carboxylic acids and their anhydrides can be used.

5.4 External Additives When the particle size of the toner is reduced, the powder characteristics tend to deteriorate, or the charge amount per toner particle tends to decrease. An agent may be added. Materials of inorganic fine powder that can be used as an external additive include titanium oxide, tin oxide, zirconium oxide,
Metal oxides such as tungsten oxide, iron oxide, and silicon oxide; nitrides such as titanium nitride; and titanium compounds. As the organic fine powder, resin fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin can be used. The amount of the external additive to be added is preferably 0.0
It is 5 to 10 parts by weight, more preferably 0.1 to 10 parts by weight.

As a method of adding the external additive to the toner, for example, a conventionally known method of adding the external additive and the colored particles to a Henschel mixer and mixing them can be adopted.

The powder properties such as powder fluidity and powder adhesion are improved, and transfer efficiency and chargeability are prevented from lowering.
At least one kind of ultrafine particles having an average primary particle diameter of at least 30 nm or more and 200 nm or less, and ultra-fine particles having an average primary particle diameter of 5 nm or more and less than 30 nm as external additives in order to reduce environmental dependency. It is preferred to use at least one of the following.

The ultrafine particles reduce the adhesion between the colored particles or between the colored particles and the photoreceptor or carrier,
It has a function of preventing a decrease in developability, transferability, or cleaning performance. The average primary particle size of the ultrafine particles is 30n
m to 200 nm, more preferably 35 nm to 1
50 nm or less, more preferably 35 nm or more and 100 n
m or less. If it exceeds 200 nm, the toner tends to be detached from the toner, and the effect of reducing the adhesive force cannot be exhibited. On the other hand, if it is less than 30 nm, it will act as ultra-fine particles described later.

The ultrafine particles have the effect of improving the fluidity of the colored particles, reducing the degree of agglomeration, and suppressing the thermal aggregation of the colored particles, and contribute to the improvement of environmental stability. The average primary particle diameter of the ultrafine particles is 5 nm or more and 30
nm, more preferably 5 nm or more and less than 29 nm, further preferably 10 nm or more and 29 nm or less. 5n
If it is less than m, the toner is easily buried in the surface of the colored particles due to stress applied to the toner. On the other hand, if it is 30 nm or more, it will function as the ultrafine particles described above. In the present specification, the “primary particle size” refers to a primary particle size equivalent to a sphere.

Examples of the ultrafine particles include metal oxides such as hydrophobized silicon oxide, titanium oxide, tin oxide, zirconium oxide, tungsten oxide, and iron oxide; nitrides such as titanium nitride; and fine particles made of a titanium compound. Preferably, the fine particles are made of hydrophobized silicon oxide. The hydrophobization is performed by treating with a hydrophobizing agent. As the hydrophobizing agent, any of chlorosilane, alkoxysilane, silazane, and silylated isocyanate can be used. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, ter -Butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane and the like.

Examples of the ultrafine particles include fine particles made of a metal oxide such as a hydrophobic titanium compound, silicon oxide, titanium oxide, tin oxide, zirconium oxide, tungsten oxide and iron oxide, and a nitride such as titanium nitride. Among them, titanium compound fine particles are preferred.

The titanium compound fine particles are a reaction product of metatitanic acid and a silane compound, which is highly hydrophobic, hardly generates agglomerates because of no baking treatment, and has good dispersibility when externally added. Preferably, there is. Also,
As the silane compound at that time, an alkylalkoxysilane compound and / or a fluoroalkylalkoxysilane compound that can control the charge of the toner well and can reduce the adhesion to the carrier and the photoreceptor are preferably used.

The metatitanic acid compound, which is a reaction product of metatitanic acid with an alkylalkoxysilane compound and / or a fluoroalkylalkoxysilane compound, is obtained by peptizing metatitanic acid synthesized by a sulfuric acid hydrolysis reaction, Those obtained by reacting metatitanic acid with an alkylalkoxysilane compound and / or a fluoroalkylalkoxysilane compound can be suitably used. Examples of the alkylalkoxysilane to be reacted with metatitanic acid include methyltrimethoxysilane,
Ethyltrimethoxysilane, propyltrimethoxysilane, isobutyltrimethoxysilane, n-butyltrimethoxysilane, n-hexyltrimethoxysilane, n-
Octyltrimethoxysilane, n-decyltrimethoxysilane and the like. Examples of the fluoroalkylalkoxysilane compound include trifluoropropyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, and heptadecafluoro. Decylmethyldimethoxysilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, (heptadecafluoro-1,1,1,2) , 2-tetrahydrodecyl) triethoxysilane, 3- (heptafluoroisopropoxy) propyltriethoxysilane and the like can be used.

By using two types of external additives, ultrafine particles and ultrafine particles, the effects of the addition of both types can be obtained.

However, if the total amount of the external additives is too large, free (not adhered to the colored particles) external additives are generated, and the photoreceptor and the carrier surface are easily contaminated with the external additives. . In addition, if both the ultrafine particles and the ultrafine particles do not have a certain amount of addition, the effect of adding both of them cannot be obtained. Further, if the amount of the ultrafine particles is too large, the effect of improving the powder fluidity cannot be obtained, and if the amount of the ultrafine particles is too large, the effect of reducing the adhesion cannot be obtained. Therefore, it is necessary to appropriately control the amount of the external additive to be added.

The appearance of the effect and the variation in the characteristics of the various powders due to the addition of the external additive do not depend on the absolute amount of the external additive to be added, but on the coverage of the surface of the colored particles. Things. Here, the coverage of the external additive on the surface of the colored particles will be described.

When it is assumed that the external additive is a true sphere having a certain size (diameter d) and that primary particles without aggregation are attached in a single layer on the surface of the colored particle, Closest packing of adhering external additives (most densely arranged)
7 is a hexagonal close packing in which six external additives 222a to 222f are adjacent to one external additive 222 as shown in FIG. 7 (FIG. 7 shows only a part of the surface of the colored particles in an enlarged manner). It is a top view).

Assuming that the state as shown in FIG. 7 is 100% as the ideal state, the actual weight of the external additive is relative to the weight of the actual colored particles. The percentage of the presence or absence is defined as the coverage in the present invention.

That is, the body of the colored particles in the actual state
The average particle size is D (μm), and the true specific gravity of the colored particles is ρ_tOutside
The average primary particle diameter of the additive is d (μm), the true specific gravity of the external additive
Is ρ _a, And the weight of the external additive x (g) and the weight of the colored particles
When the ratio (x / y) to the amount y (g) is C, the coverage is
F (%) is: F = C / ｛2π · d · ρ_a/ (√3 · D · ρ_t)｝ × 1
00, which can be rearranged into the following equation (1).

F = √3 · D · ρ _t · (2π · d · ρ _a ) ⁻¹ · C × 100 (1) (In the above formula, F is the coverage (%), and D is the colored particles. , Ρ _t is the true specific gravity of the colored particles, d is the primary particle average particle size of the external additive (μm), ρ _a is the true specific gravity of the external additive,
And C are the weight of the external additive x (g) and the weight of the colored particles y
(G) and the ratio (x / y). )

The coverage of the external additive on the surface of the colored particles determined by the above formula (1) is preferably 20% or more for both the ultrafine particles Fa and the ultrafine particles Fb. It is preferable that the sum of the rates is 100% or less. In addition, "the total of the coverage of all the external additives"
The coverage for each external additive added is calculated individually,
It refers to the sum of the coverages of the obtained external additives.

If the covering rate Fa of the ultrafine particles is less than 20%, the effect of adding the ultrafine particles may not be obtained in some cases.
The coverage Fa of the ultrafine particles is preferably from 20 to 80%, more preferably from 30 to 60%.

If the coverage Fb of the ultrafine particles is less than 20%, the effect of adding the ultrafine particles may not be obtained. The ultra-fine particle coverage Fb is preferably 20 to
80%, more preferably 30 to 60%.

When the total coverage of all external additives exceeds 100%, a large amount of free external additives is generated, and the photoreceptor and the carrier surface are easily contaminated with the external additives. The total of the coverage of all the external additives is preferably 40 to 100%, more preferably 50 to 90%.

The relationship between the ultrafine particle coverage Fa (%) and the ultrafine particle coverage Fb (%) more preferably satisfies the following expression (3). 0.5 ≦ Fb / Fa ≦ 4.0 (3) Outside this range, it is difficult to obtain the effect of adding ultrafine particles or ultrafine particles, which is not preferable. Also,
In order to optimize the effect of adding ultrafine particles or ultrafine particles, it is more preferable to satisfy the following expression (3 ′). 0.5 ≦ Fb / Fa ≦ 2.5 (3 ′)

As a method for adding the ultrafine particles and the ultrafine particles to the toner, for example, a conventionally known method of adding the ultrafine particles, the ultrafine particles and the colored particles to a Henschel mixer and mixing them can be adopted.

5.5 Relationship between Charge Amount q and Particle Size d (q /
d value) The charge amount of the toner is q (fC), and the particle diameter of the toner is d (μC).
m), the toner in the developer tank is q
The peak value in the frequency distribution of / d value is preferably 1.0 or less, more preferably 0.80 or less,
More preferably, it is 0.70 or less. On the other hand, the bottom value is preferably not less than 0.005, more preferably not less than 0.01, and particularly preferably not less than 0.02. When the charge amount of the toner is within the above range, developability and transferability are further improved. In addition, as q / d value,
In the case of a positively charged toner, the above numerical specifications are applied as it is, but in the case of a negatively charged toner, the charge amount q
After reversing the value of (fC), the above numerical rules are applied.

The charge amount here is a temperature of 20 ° C., a humidity of 5
The values measured in a 0% environment are shown, which is based on the fact that the toner is usually used in the environment. When the q / d value is measured for each toner and its frequency distribution is graphed, the distribution is approximately a normal distribution having an upper limit and a lower limit. The q / d value of the point that is the top of this graph is the peak value, and the q / d value of the point that is the lower limit (in the case of negatively charged toner, the lower limit after reversing the sign) is the bottom value.

The frequency distribution of the q / d value is described in, for example,
It can be measured by a charge spectrograph method (hereinafter, referred to as "CSG method") described in JP-A-799958. Hereinafter, a specific measurement method will be described.

FIG. 8 is a schematic perspective view of a measuring device 100 for measuring the frequency distribution of the q / d value by the CSG method. The measuring apparatus 100 includes a cylindrical body 112, a filter 114 for closing a lower opening thereof, a mesh 116 for closing an upper opening, and a sample supply projecting from the center of the mesh 116 to the inside of the body 112. Tube 118,
A suction pump (not shown) that sucks air from the lower opening of the body 112 and an electric field generator (not shown) that applies an electric field E from the side surface of the body 112.

The suction pump is set to uniformly suck the air inside the body 112 through the filter 114 at the lower opening of the body 112. Accordingly, air flows in from the mesh 116 at the upper opening, and a laminar flow with a constant air flow velocity Va is generated vertically downward inside the body 112. In addition, the electric field generator generates a uniform and constant electric field E in a direction orthogonal to the air flow.
Is given.

The toner particles to be measured are gradually dropped (dropped) from the sample supply tube 118 into the body 112 in the above state. Unless affected by the electric field E, the toner particles coming out of the sample outlet 120 at the tip of the sample supply cylinder 118 fly vertically downward while being affected by the laminar air flow, and reach the center O of the filter 114. (At this time, the distance k between the sample outlet 20 and the filter 14 is the straight flight distance of the toner). The filter 114 is formed of a coarse polymer filter or the like, and allows air to sufficiently pass therethrough, but does not allow toner particles to pass through and remains on the filter 114. However, in the case of the charged toner, the position of the filter 114 is shifted from the center O in the direction of travel of the electric field E, and is affected by the electric field E.
It reaches above (point T in FIG. 8). By measuring the distance (displacement) x between the point T and the center O and obtaining the frequency distribution, the frequency distribution of the q / d value can be obtained (in the present invention, the peak is actually obtained by image analysis). Values and bottom values were determined directly.)

More specifically, the relationship between the displacement x (mm) obtained by the measuring device 100 as described above, the charge amount q (fC) of the toner, and the particle size d (μm) of the toner is described. Is represented by the following equation (4). q / d = (3πηVa / kE) × x (4) In equation (4), η is the viscosity of air (kg / m · sec.),
Va represents the air flow velocity (m / sec.), K represents the straight flight distance (m) of the toner, and E represents the electric field (V / m).

In the present invention, each condition of the expression (4) is
The measurement is performed by setting each condition of the measuring apparatus 100 shown in FIG. 8 so that the following numerical values are obtained. Air viscosity η = 1.8 × 10 ⁻⁵ (kg / m · sec.) Air flow rate Va = 1 (m / sec.) Toner straight flight distance k = 10 (cm) Electric field E = 190 V / cm

When the above values are substituted into equation (4), the following is obtained. q (fC) / d (μm) ≒ 0.09 · x

When toner particles to be measured are dropped into the sample supply cylinder 118, the toner needs to be charged in advance. It is preferable that the q / d value of the toner is within the above range in an environment in which the toner is actually used. Therefore, the toner to be measured is adjusted so as to have a mixing ratio with the carrier in the actual developer tank. After being mixed with a carrier and sufficiently charged by shaking or the like, it is preferable to use this for measurement of the frequency distribution of the q / d value.

5.6 Other Additives The toner may contain a charge control agent, a release agent, and the like, if necessary, within a range that does not affect color reproducibility and transparency. Examples of the charge control agent include chromium azo dyes, iron azo dyes, aluminum azo dyes, salicylic acid metal complexes, and organic boron compounds. Examples of the release agent include polyolefins such as low-molecular-weight propylene and low-molecular-weight polyethylene, and natural waxes such as paraffin wax, candelilla wax, carnauba wax, and montan wax, and derivatives thereof.

6. Carrier The carrier is not particularly limited, and magnetic particles such as iron powder, ferrite, iron oxide powder, nickel, and the like are used as a core material, and the surface thereof is made of a styrene resin, a vinyl resin, an ethyl resin, a rosin. Disperse magnetic particles in coated resin-type carrier particles formed by coating with a known resin such as a base resin, a polyester resin, or a methyl resin, or a wax such as stearic acid to form a resin coating layer, or a binder resin. Magnetic-particle-dispersed carrier particles can be used.

Among them, a coated resin type carrier having a resin coating layer is particularly preferable because the chargeability of the toner and the resistance of the entire carrier can be controlled by the configuration of the resin coating layer. As the material of the resin coating layer, any resin conventionally used in the art as a material of the resin coating layer of the carrier can be selected. In addition, the type of the resin may be single or two or more.

The particle size of the carrier is preferably 45 μm or less as a volume average particle size, more preferably 10 to 40 μm. By adjusting the volume average particle diameter of the carrier to 45 μm or less, the toner (colored particles)
The background contamination and density unevenness resulting from the rise of charge, the deterioration of charge distribution, and the decrease in charge amount due to the reduction of the particle size can be improved.

[0088]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. 1) Preparation example of magenta flushing pigment Polyester resin (bisphenol A type polyester:
Bisphenol A ethylene oxide adduct-cyclohexane dimethanol-terephthalic acid, weight average molecular weight:
11,000, number average molecular weight: 3,500, Tg: 65
C) 70 parts by weight and a magenta pigment (CI Pigment Red 57: 1) water-containing paste (pigment content 40% by weight) 75
The parts by weight were put into a kneader-type kneader, mixed, and gradually heated. Kneading was continued at 120 ° C., and after the water phase and the resin phase were separated, water was removed. The resin phase was kneaded to remove water, and dewatered to obtain a magenta flushing pigment.

2) Preparation of Magenta Colored Particles <Preparation Example 1 of Magenta Colored Particles> Polyester resin (bisphenol A type polyester: bisphenol A ethylene oxide adduct-cyclohexanedimethanol-terephthalic acid, weight-average molecular weight: 11,000; Number average molecular weight: 3500, Tg: 65 ° C.) 67 parts by weight ・ The above magenta flushing pigment (pigment content: 30% by weight) 33 parts by weight The above components are melt-kneaded by a Banbury mixer, cooled, then finely pulverized by a jet mill and wind power Classification was performed by a classifier to obtain magenta colored particles.

3) Preparation of Magenta Toner Silica (SiO ₂ ) fine particles having an average primary particle diameter of 40 nm, which were obtained by subjecting the magenta colored particles to a surface hydrophobic treatment with hexamethyldisilazane (hereinafter sometimes abbreviated as “HMDS”). And metatitanic acid compound fine particles having a primary particle average particle diameter of 20 nm, which is a reaction product of metatitanic acid and isobutyltrimethoxysilane, are added so that the total coverage of the surface of each colored particle is 80%. The mixture was mixed with a mixer to produce a magenta toner.
Here, the coverage of the surface of the colored particles refers to the value F (%) obtained by the above-mentioned equation (2).

4) Preparation of Carrier A methanol solution containing 0.1 part by weight of γ-aminopropyltriethoxysilane was added to 100 parts by weight of Cu—Zn ferrite fine particles having a volume average particle diameter of 40 μm, and coated with a kneader. The methanol is distilled off and an additional 120
C. for 2 hours to completely cure the silane compound. The particles were added to a perfluorooctylethyl methacrylate-methyl methacrylate copolymer (copolymerization ratio: 40:
60) was dissolved in toluene, and a resin-coated carrier was added using a vacuum reduced pressure kneader such that the coating amount of the perfluorooctylethyl methacrylate-methyl methacrylate copolymer was 0.5% by weight. Was manufactured.

5) Preparation of Developer 4 parts by weight of the obtained magenta toner was mixed with 100 parts by weight of the obtained resin-coated carrier to prepare a magenta electrostatic latent image developer, which is shown below. It was used as a developer in Example 1.

In the above-mentioned method for producing a magenta electrostatic latent image developer, the same conditions as above were used except that the conditions such as the amount and type of pigment particles used, the conditions for pulverizing and classifying colored particles, the coverage of external additives, and the pigment concentration were changed. Then, the toner and the developer used in Examples 2 to 7 and the toner and the developer used in Comparative Examples 1 to 7 were produced. Various properties of toner and developer used in Examples 1 to 7 and Comparative Examples 1 to 7, and
Table 1 summarizes the respective DMAs and TMAs (measurement conditions will be described later). Examples 2 to 7
The developer used in Comparative Example 7 was prepared by mixing 4 parts by weight of the toner and 100 parts by weight of the carrier, and the developer used in Comparative Example 1 was prepared by mixing 5 parts by weight of the toner and 100 parts by weight of the carrier. Comparative Examples 2 to 6 were prepared by mixing 6 parts by weight of the toner and 100 parts by weight of the carrier. In the table, M is magenta, K is black, C is cyan,
Y indicates yellow. The pigment particles used for the M toner were the same as in Example 1, and the carbon toner used was carbon black (primary average particle diameter 40 nm).
As the pigment particles used for the C and Y toners, flushing pigments manufactured by the following method were used.

<Cyan flushing pigment> A cyan flushing pigment was prepared in the same manner as the magenta flushing pigment except that the water-containing paste for magenta pigment was replaced with a water-containing paste (pigment blue 15: 3) (pigment content: 40% by weight). Was prepared. <Yellow flushing pigment> A water-containing paste of magenta pigment is used as a yellow pigment (CI Pigment Yellow 17).
A yellow flushing pigment was produced in the same manner as the magenta flushing pigment except that the paste was replaced with a water-containing paste (pigment content: 40% by weight).

[0095]

[Table 1]

The peak value and bottom value of q / d in the table are obtained by measuring the frequency distribution of q / d values for each toner under the environment of a temperature of 20 ° C. and a humidity of 50% by the CSG method. These are the obtained peak value and bottom value.

Example 1 The prepared developer was stored in the developer tank 110 of the developing device A shown in FIGS.
The prepared carriers were stored in the carrier supply tanks 112, respectively. The dispense member 1 is supplied such that the supply amount of toner and carrier from each supply tank is 4: 1 by weight.
14 and 115. A developing device that stores the respective developers is used as a copier (“A color 93”).
5 ", a remodeled machine manufactured by Fuji Xerox Co., Ltd.) to form an image on coated paper (" FX J Coat ", manufactured by Fuji Xerox Co., Ltd.). DMA and TMA at the time of image formation were measured by the following methods. Further, the following evaluation was performed on the obtained initial image. The evaluation results are shown in Table 2.

<Measurement of DMA> A solid image (toner image) having an area ratio of 100% is formed on a photosensitive member, and the weight of the toner per unit area of the image portion (DMA: mg / c)
m ² ) was measured. As a specific measuring method, 10c
A solid image having an area of m ² was formed on the photoreceptor and completely transferred to a weighed mending tape. Thereafter, the mending tape was weighed, and the DMA was calculated from the weight difference.

<Measurement of TMA> A solid image having an area ratio of 100% was transferred onto coated paper, and the weight of the toner per unit area of the image portion (TMA: mg / cm ² ) was measured. As a specific measuring method, an unfixed solid image having an area of 10 cm ² is formed on coated paper, weighed, and then the toner on the coated paper is removed by air blow, and then the weight of the coated paper alone is measured. TMA was calculated from the difference in weight before and after the removal of the toner.

Evaluation of Image <Image Density> A solid fixed image having an area ratio of 100% was prepared, and the image density of the image portion was measured using X-Rite404 (manufactured by X-Rite). Image density 1.
5 or more was regarded as an allowable range. In Table 2, ○ and × have the following meanings. : The image density is 1.5 or more. X: The image density is less than 1.5.

<Image Fogging> The occurrence of fogging was visually observed for the image at the initial stage of repeated copying. In Table 2, ○ and × have the following meanings. : No fog occurred on the image. ×: Fogging occurred in the image.

<Evaluation test of reproducibility of fine line>
A fine line image was formed so as to have a thickness of 0 μm, and the image was transferred and fixed on a transfer material. The fine line image of the fixed image on the transfer material was observed at a magnification of 175 times using a VH-6200 micro high scope (manufactured by Keyence Corporation). The specific evaluation criteria are as follows. In addition, G1 and G2 were set as the allowable range. G1: The fine line is uniformly buried with the toner, and there is no disturbance at the edge portion. G2: The fine line is uniformly buried with the toner, but slight jaggedness is observed at the edge. G3: The fine line is almost uniformly buried by the toner, but the jaggedness at the edge is noticeable. G4: The fine line is not evenly buried with the toner, and the edge portion is noticeably jagged. G5: The fine line is not evenly buried by the toner, and the jaggedness at the edge is noticeable.

<Gradation Reproducibility Evaluation Test> Image area ratio 5%,
10%, 20%, 30%, 40%, 50%, 60%, 7
Gradation images of each level of 0%, 80%, 90%, and 100% were created, and the image density was measured with X-Rite 404 (manufactured by X-Rite) to determine the gradation. Further, using a VH-6200 microscope (manufactured by Keyence Corporation), the above images having an image area ratio of 5% and 10% were observed at a magnification of 175 times, and image reproducibility at a low image area ratio was determined. From these results, the gradation reproducibility was evaluated according to the following evaluation criteria. G1 and G2 were set as acceptable ranges. G1: Both gradation and image reproducibility at a low image area ratio are good. G2: Although the gradation is good, the image at a low image area ratio is slightly unstable. G3: The tone reproduction area at a low image area ratio is slightly narrow, and the image at a low image area ratio is somewhat unstable. G4: The gradation reproduction area at the high / low image area ratio is slightly narrow, and the image at the low image area ratio is slightly unstable. G5: The gradation reproduction region at the high / low image area ratio is narrow, and the image at the low image area ratio is unstable.

Examples 2 to 7 and Comparative Examples 1 to
Example 7 An image was formed using the other prepared electrostatic latent image developers in the same manner as in Example 1, and TMA was measured. The evaluation results are shown in Table 2.

[0105]

[Table 2]

Example 8 and Comparative Example 8 A multicolor image was formed by combining K, C, M, and Y toners, a photographic image was output, and the uniformity of the obtained photographic image was determined according to the following criteria. Was evaluated. Table 3 summarizes the combinations of the toners contained in the used developer and the evaluation results of the uniformity of the photographic image. In the table, “actual n” indicates “developer used in Example n”, and “ratio n” indicates “developer used in Comparative Example n”. <Uniformity of photographic image> The degree of uniformity caused by the difference in the unevenness of the image between the image part and the non-image part and between the high density part and the low density part of the image was visually determined. ○ is set as an allowable range. ：: Image quality equivalent to a photographic image obtained by printing. Δ: Uniformity is slightly inferior to photographic images obtained by printing. X: The uniformity is clearly inferior to the photographic image obtained by printing.

[0107]

[Table 3]

<Evaluation of Stability of Image Formation> Example 9 Using the developer used in Example 1, the copying machine was continuously operated, and the number of copies until an image was fogged was counted. The toner consumption was 20 mg per A4 size sheet. As a result, a stable image density was maintained even after continuous copying of 30,000 sheets, and no fogging occurred in the image. Table 4 shows fine line reproducibility and gradation reproducibility (the evaluation method is the same as described above) after 30,000 sheets of continuous copying.

Example 10 Using the developer used in Example 2, the image stability was evaluated in the same manner as in Example 9. As a result, a stable image density was maintained even after continuous copying of 30,000 sheets, and no fogging occurred in the image. Table 4 shows fine line reproducibility and gradation reproducibility (the evaluation method is the same as described above) after 30,000 sheets of continuous copying. Example 11 The image stability was evaluated in the same manner as in Example 9, except that the developer used in Example 3 was used. As a result, a stable image density was maintained even after continuous copying of 30,000 sheets, and no fogging occurred in the image. Table 4 shows fine line reproducibility and gradation reproducibility (the evaluation method is the same as described above) after 30,000 sheets of continuous copying.

[0110]

[Table 4]

Example 12 Continuous copying was performed in the same manner as in Example 9 except that the dispensing setting was changed so that the toner and carrier replenishment amounts were 4: 1 by weight, but 40: 1. went. 1
The image was good up to about 5000 sheets, but 1500
From the time when the number of sheets exceeded zero, fogging occurred in the image.

Comparative Example 9 The developer used in Example 1 was used and stored in a non-trickle type developing device (developing device not provided with a toner replenishing means and a developer discharging means). Was operated continuously, fog was observed in the image when 10,000 sheets were continuously copied. Comparative Example 10 The developer used in Example 2 was used and stored in a non-trickle type developing device (developing device not provided with a toner supply means and a developer discharging means), and the copier was continuously operated. The fogging was observed in the image when 10,000 sheets were continuously copied. Comparative Example 11 The developer used in Example 3 was used and stored in a non-trickle type developing device (developing device not provided with a toner supply means and a developer discharging means), and the copier was continuously operated. The fogging was observed in the image when 10,000 sheets were continuously copied.

[0113]

According to the image forming method of the present invention, fine line reproducibility and gradation reproducibility can be stably obtained without causing fogging due to carrier contamination and reduction in image density. An image without unevenness caused by a step can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of an image forming apparatus used to carry out an image forming method of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 5, illustrating an embodiment of the developing device used in the image forming method of the present invention.

FIG. 3 is a sectional view of the developing device, taken along line III-III of FIG. 5;

FIG. 4 is a sectional view of the developing device, taken along line IV-IV of FIG. 5;

FIG. 5 is a top view of the developing device.

FIG. 6 is a cross-sectional view of another embodiment of the developing device used in the image forming method of the present invention.

FIG. 7 is an enlarged plan view showing a part of the surface of a colored particle.

FIG. 8 is a schematic perspective view of a measuring device 100 for measuring a frequency distribution of q / d values by a CSG method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charger 3 Exposure means 5 Transfer charger 6 Cleaner 7 Recording paper 110 Developer tank 111 Toner supply tank 112 Carrier supply tank 113 Developer discharge tank 114 Toner dispense 115 Carrier dispense 116 Toner supply port 117 Carrier supply port 118 Developer outlet 119 Auger 120 Patroller 121 Developing roll 122 Magnetic roll 123 Developing sleeve 124 Blade 131 Replenishing developing layer replenishing tank 134 Dispense

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme coat ゛ (Reference) G03G 15/08 507L 507D F-term (Reference) 2H005 AA08 AA21 AB10 BA06 CA21 CB07 CB13 EA01 EA05 EA07 EA10 FA02 2H077 AB02 AB03 AB07 AB18 AC02 AD06 BA08 CA19 EA03 GA13

Claims (11)

[Claims] 1. A developer tank for storing a developer comprising a toner and a carrier, a toner replenishing means for replenishing the developer tank with toner, a carrier replenishing means for replenishing the developer tank with carrier, and a developer tank. Developing a toner image by developing the electrostatic latent image formed on the electrostatic latent image carrier with a toner using a developing device having a discharging unit that discharges the developer from the developing device; A transfer step of transferring to a transfer material, wherein the toner comprises colored particles containing at least a binder resin and a colorant, and the volume average particle size of the colored particles is 1.0 to 1.0. 5.0 μm,
Colored particles of 1.0 μm or less are 20% by number or less,
An image forming method, wherein the number of colored particles exceeding 5.0 μm is 10% by number or less. 2. The weight ratio of the amount of toner per unit time supplied from the toner supply unit to the amount of carrier per unit time supplied from the carrier supply unit is 1: 1 to 30: 1. The image forming method according to claim 1, wherein: 3. A developer tank for storing a developer comprising a toner and a carrier, a replenishing means for replenishing the developer tank with a replenishing developer comprising a toner and a carrier, and discharging the developer from the developer tank. Using a developing device having a discharging unit for developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image, and transferring the toner image to a transfer material An image forming method including a transfer step, wherein the toner comprises colored particles containing at least a binder resin and a coloring agent, and the volume average particle size of the colored particles is 1.0 to 5.0 μm. ,
Colored particles of 1.0 μm or less are 20% by number or less,
An image forming method, wherein the number of colored particles exceeding 5.0 μm is 10% by number or less. 4. The image forming method according to claim 3, wherein the replenishing developer contains the toner and the carrier in a weight ratio of 1: 1 to 30: 1. 5. The amount of charge of the toner in an environment at a temperature of 20 ° C. and a humidity of 50% is q (fC), and the particle size of the toner is d (μ
m), the peak value in the frequency distribution of the q / d value of the toner in the developer tank is 1.0 or less, and the bottom value is 0.005 or more. The image forming method according to any one of claims 1 to 4, wherein the method is performed. 6. An external additive is further added to the toner,
And (a) the external additive is at least 30 nm or more and 200
at least one kind of ultrafine particles having a primary particle average particle diameter of 5 nm or less and less than 30 nm, and (b) the following formula (1): The required coverage of the external additive on the surface of the colored particles is 20% or more for both the ultrafine particles Fa and the ultrafine particles Fb, and the total coverage of all the external additives is 100%.
% Or less.
The image forming method according to any one of the above. F = √3 · D · ρ _t (2π · d · ρ _a ) ⁻¹ · C × 100 (1) (where F is the coverage (%) and D is the volume average of the colored particles. Particle size (μm), ρ _t is the true specific gravity of the colored particles, d is the average primary particle size of the external additive (μm), ρ _a is the true specific gravity of the external additive,
And C are the weight of the external additive x (g) and the weight of the colored particles y
(G) and the ratio (x / y). ) 7. The coloring agent is a pigment particle, the concentration of the pigment particle in the coloring particle is C (% by weight), the true specific gravity of the coloring particle is a (g / cm ³ ), and the volume average particle diameter of the coloring particle is 7. Satisfies the relationship of the following expression (2) when is set to D (μm).
Item. 25 ≦ a · D · C ≦ 90 (2) 8. The image area ratio on an electrostatic latent image carrier is 100%.
8. The image forming method according to claim 1, wherein the electrostatic latent image is developed with a toner amount of 0.5 mg / cm ² or less. 9. A replenishing developer used in the image forming method according to claim 3, comprising: a toner and a carrier in a weight ratio of 1: 1 to 30: 1, wherein the toner has at least a binder. It is composed of colored particles containing a resin and a colorant, and has a volume average particle size of 1.0 to 5.0 μm,
Colored particles of 1.0 μm or less are 20% by number or less,
A replenishing developer characterized in that colored particles exceeding 5.0 μm are 10% by number or less. 10. An external additive is further added to the toner, and (a) the external additive is at least 30 nm or more.
Ultrafine particles 1 having an average primary particle diameter of 00 nm or less
And at least one kind of ultra-fine particles having an average primary particle diameter of 5 nm or more and less than 30 nm, and (b) the coverage of the external additive on the surface of the colored particles determined by the following formula (1) is: It is at least 20% for both the ultrafine particles Fa and the ultrafine particles Fb, and the total coverage of all external additives is 100%.
%. The replenishing developer according to claim 9, wherein the amount is not more than%. F = √3 · D · ρ _t (2π · d · ρ _a ) ⁻¹ · C × 100 (1) (where F is the coverage (%) and D is the volume average of the colored particles. Particle size (μm), ρ _t is the true specific gravity of the colored particles, d is the average primary particle size of the external additive (μm), ρ _a is the true specific gravity of the external additive,
And C are the weight of the external additive x (g) and the weight of the colored particles y
(G) and the ratio (x / y). ) 11. The replenishing developer according to claim 9, wherein the carrier has a resin coating layer.