JP2646285B2 - Non-magnetic color toner and image forming method - Google Patents

Description

The present invention relates to a non-magnetic color toner and an image forming method using the non-magnetic color toner. Specifically, the present invention relates to an organic semiconductor ( An image is formed using a photoreceptor (hereinafter, referred to as an “OPC photoreceptor”) composed of OPC) as an image carrier, and the image is transferred to a transfer material, while a residual image on the image carrier is subjected to blade cleaning. The present invention relates to an image forming method of forming an image by repeatedly cleaning an image carrier and using an image carrier, and in particular, an electrophotographic method using an OPC photosensitive member is an image forming method for a color copying machine or a printer. It can be suitably embodied as a method.

[Related Art] In recent years, a large number of image forming apparatuses such as electrophotographic color copying machines or printers using an OPC photosensitive member as an image carrier have been manufactured. Usually, such an image forming apparatus includes:
Form a latent image on the OPC photoreceptor by a normal electrophotographic process, develop the latent image with a developing device to form a toner image,
The image is transferred to a transfer material to obtain a visible image. on the other hand,
The residual image on the image carrier is cleaned by a cleaning unit,
The image carrier is used repeatedly.

As the cleaning means, a blade cleaning means having a structure in which a cleaning blade made of a rubber elastic material is pressed against an image carrier is widely used because it is simple and compact in structure and is very advantageous in terms of cost. ing.

As a result of many research experiments, the present inventors have found that when an OPC photoconductor is used as an image carrier, as shown in FIG.
It has been found that the friction coefficient of the image carrier increases as the temperature increases.

In general, the OPC photoreceptor has a configuration in which a charge generation layer composed of a binder in which a charge generation material is dispersed on a conductive support, and a charge transport layer composed of a binder in which a charge transport material is dispersed are stacked in this order, As the charge generation material, phthalocyanine pigments, anthrone pigments, azo pigments, pigments such as indigo pigments, dyes such as pyridium dyes, or dyes such as cyanine dyes, and the like, and charge transport materials such as pyrene,
Carbazoles such as isopropylcarbazole, hydrazones, pyrazolines, oxasonyl compounds, thiazole compounds, triarylmethane compounds, polyarylalkanes and the like are used. , Polyamide resin, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenolic resin, epoxy resin, polyester resin, alkyd resin,
Polycarbonate, polyurethane, or a copolymer resin containing two or more of the repeating units of these resins, such as a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, and a styrene-maleic acid copolymer, are used.

According to the results of research experiments conducted by the present inventors, the cause of the increase in the friction coefficient with the temperature increase of the image carrier is due to the temperature characteristics of the binder occupying most of the surface of the OPC photoconductor. I understood that.

When the friction coefficient of the image carrier increases as described above, the friction between the cleaning blade of the cleaning means and the surface of the image carrier increases, and especially when the temperature of the image carrier exceeds 45 ° C., the friction coefficient sharply increases. Increases, the cleaning blade starts to vibrate, the edge of the cleaning blade is damaged, and furthermore, if the blade is disposed opposite to the moving direction of the image carrier, the blade is turned up. As a result, the cleaning action was significantly reduced.

In order to solve such a problem, fine particles of a fatty acid metal salt (for example, zinc stearate) or a fluorine compound are externally added as a lubricant to the developer, and a thin layer of the lubricant is formed on the surface of the image carrier during development. Attempts have been made to reduce the friction coefficient of the surface of the image carrier.

However, it is composed of a mixture of toner particles and magnetic particles (carrier). When these lubricants are externally added to a so-called two-component developer, the lubricant adheres to the carrier surface (carrier contamination) due to long-term use, resulting in instability of the toner tripo and ground fog. In addition, problems such as a decrease in image density and contamination inside the apparatus due to toner scattering occurred. Particularly in an image forming apparatus such as a full-color copying machine in which an image carrier is continuously rotated and an image forming process of charging → exposure → development → transfer is performed a plurality of times on the same transfer material to obtain a full-color image. Ground fog was also transferred multiple times, resulting in extreme ground fog.

On the other hand, it has been proposed to dispose a lubricant applying means before and after the cleaning means so as to reduce the friction coefficient of the surface of the image carrier. However, this is not preferable in view of an increase in size and complexity of the apparatus. .

Furthermore, it is also possible to lower the friction coefficient of the drum surface by dispersing fine particles of a fatty acid metal salt or a fluorine-based compound as a lubricant in a binder of the OPC photoreceptor,
According to the results of the research experiments of the present invention, the lubricant dispersed in the binder adversely affects the photosensitive characteristics of the OPC photoconductor, causing uneven charging on the photoconductor surface, an increase in residual potential, etc. It turned out to be harmful to them.

Further, when the temperature of the image carrier exceeds 45 ° C., the toner having a relatively low melting temperature used in a full-color image forming apparatus or the like causes blocking (aggregation) at the edge of the cleaning blade, and usually the edge of the cleaning blade. The problem is that toner with a particle size of 3.0 μm or less, which acts as a lubricant after passing through, or a fine particle external additive such as silica also agglomerates, causing the particle size to become coarse and not functioning as a lubricant. I do.

In general, in an electrophotographic copying machine or the like, as the number of copies increases, toner or an external additive of toner or components in a transfer material or corona discharge generated when the image carrier is charged is generated. Hydrophilic substances such as nitrogen oxides adsorb. Since the hydrophilic substance absorbs moisture (condensation) due to a change in atmosphere or the like, when the image carrier to which the hydrophilic substance is adsorbed is charged, uneven charging occurs, and the copied image blurs, The result is a defective image called. As a countermeasure, it has been found that it is generally necessary to heat the image carrier to 35 ° C. or higher to prevent moisture absorption (condensation).

On the other hand, in recent years, as image forming apparatuses such as color copying machines for electrophotography have become widespread, their uses have been diversified, and requirements for image quality have become strict. 2. Description of the Related Art In copying an image such as a general photograph, catalog, or map, it is required to reproduce extremely finely and faithfully without being crushed or broken down to a minute portion.

Further, recently, in an image forming apparatus such as an electrophotographic color copying machine using a digital image signal, a latent image is formed by collecting dots of a constant potential, and a solid portion, a halftone portion and a light portion are formed. Is expressed by changing the dot density. However, in a state where the toner particles do not adhere to the dots and the toner particles protrude from the dots, it is not possible to obtain the gradation of the toner image corresponding to the dot density ratio of the black portion and the white portion of the digital latent image. There is a problem. Further, when the resolution is improved by reducing the dot size in order to improve the image quality, the reproducibility of a latent image formed from minute dots becomes more difficult, and the resolution and especially the gradation of the highlight portion are improved. Image tends to be poor and lacks sharpness.

Although the image quality is good at the beginning, the image quality may deteriorate while copying or printing out is continued. It is considered that this development is caused by the fact that only the toner particles that are easily developed during the copying or printing out are consumed first, and the toner particles having poor developability accumulate and remain in the developing machine.

Heretofore, several developers have been proposed for the purpose of improving image quality. JP-A-51-3244 proposes a non-magnetic toner intended to improve image quality by regulating the particle size distribution. In the toner, 8.0 to 12.
The main component is a toner having a particle size of 0 μm, which is relatively coarse. According to the study of the present inventors, it is difficult for the toner to have a dense “glue” to a latent image, and the particle size of 5.0 μm or less is 30 μm.
From the characteristic that the particle size distribution is not more than 5% by number and not more than 20.0 μm, the uniformity tends to be reduced in that the particle size distribution is broad. In order to form a clear image using such a coarse toner particle and a toner having a broad particle size distribution, it is necessary to fill the gaps between the toner particles by thickly overlapping the toner particles so that an apparent image is formed. There is also a problem that it is necessary to increase the density, and the amount of toner consumption required for obtaining a predetermined image density increases.

Japanese Patent Application Laid-Open No. Sho 54-72054 proposes a non-magnetic toner having a sharper distribution than the former, however, the size of particles having an intermediate weight is as coarse as 8.5 to 11.0 μm, and a fine dot latent image is formed. There is still room for improvement as a high-resolution color toner that faithfully reproduces.

In JP-A-58-129737, the average particle diameter is 6.0 to 10.0.
Non-magnetic toner having a maximum particle size of 5.0 to 8.0 μm has been proposed.
There is a tendency that an image lacking in sharpness is formed.

According to the study of the present inventors, it has been found that toner particles of 5.0 μm or less clearly reproduce fine dots of a latent image and have a main function of dense toner gluing on the entire latent image. Was. In particular, in the electrostatic latent image on the photoconductor, since the lines of electric force are concentrated, the contour edge portion has a higher electrolytic strength than the inside, and the sharpness of the image quality is determined by the quality of the toner particles collected in this portion. According to the study by the present inventors, it has been found that the amount of particles having a particle size of 5.0 μm or less is effective for solving the problem of highlight gradation.

However, toner particles having a size of 5.0 μm or less have a particularly strong adhesion to the surface of the image carrier, and are difficult to clean. The adhesive force to the surface of the image carrier is further enhanced in a low-temperature and low-humidity environment where the absolute temperature is low. In addition, the rubber elastic material described above shows a large change in characteristics depending on the environmental temperature. (Approximately below ℃), the creep recovery (the time course of the strain when the stress is suddenly removed where the strain is present) deteriorates, resulting in an extremely low cleaning ability.

Therefore, in order to clean the color toner of 5.0 μm or less, a rubber elastic material that does not deteriorate the creep recovery even in a low temperature environment is required. As a result of the study by the present inventors, it has been found that there is a correlation between the creep recovery state and the peak temperature of the loss coefficient tanδ in the dynamic viscoelasticity data of the rubber elastic material.

That is, the peak temperature of the loss coefficient of the rubber elastic material, tan δ, means the temperature at which elastic deformation of the rubber elastic material occurs, and the lower the peak temperature, the better the creep recovery state of the rubber elastic material in a low temperature environment is maintained. .

The present inventors used a color toner having a volume average particle diameter of 10.0 μm or less by using a cleaning blade having a peak temperature of a loss coefficient tan δ of a rubber elastic material of 0 ° C. or less as a means for cleaning the image carrier. The cleaning ability of the image forming apparatus in a low-temperature and low-humidity environment (about 15 ° C. or higher) has been improved.

However, although the cleaning characteristics have been remarkably improved by adopting the above-mentioned means, it is not necessary to optimize the selection of the developer or the particle size distribution of the toner, especially the amount of fine powder of the toner and the type and the amount of the external additive added to the toner. In other words, it has been found that it is difficult to maintain the initial level, for example, when the printout is continuously performed.

This is because the toner is fixed on the photoreceptor due to low electrical resistance such as paper dust or ozone adducts by continuously printing out. For the purpose of scraping off such low electric resistance and adhered toner, JP-A-60-32060 or JP-A-60-136752 discloses that the BET specific surface area by nitrogen adsorption is 0.5 to 30 m ² / g. It has been proposed to add inorganic fine powder as an abrasive.

Although this method is effective in avoiding the toner sticking phenomenon, it is not sufficient in stability without improving the cleaning blade for applying to the small-diameter, high-resistance color toner in the present invention. Was.

Further, as a result of extensive studies by the present inventors, the loss coefficient tan
Even when a cleaning blade having a peak temperature of δ of 0 ° C. or less is used, when 15 to 40% by number of toner particles of 5.0 μm or less are included to achieve high image quality, the volume average diameter of the toner is 0.05%. It has been found that a spherical titanium oxide produced by a sol-gel method of up to 2.0 μm is particularly effective for improving the cleaning property, can achieve high image quality, and is effective for solving the problems.

[Problems to be Solved by the Invention] An object of the present invention is to provide a non-magnetic color toner and an image forming method which solve the above-mentioned problems.

A further object of the present invention is to provide a non-magnetic color toner having a high image density, excellent fine line reproducibility, and excellent highlight gradation, and an image forming method.

Another object of the present invention is to provide a non-magnetic color toner and an image forming method which do not change in performance even when used for a long time.

Means and Action for Solving the Problems According to the present invention, in a non-magnetic color toner having at least a colorant-containing resin particle and two or more additives, at least one of the additives is produced by a sol-gel method. It is a spherical titanium oxide having a volume average particle diameter of 0.05 to 2.0 μm, and the spherical titanium oxide is contained in an amount of 0.03 to 3% by weight based on the colorant-containing resin particles. Colorant-containing resin having a volume average particle diameter in the range of 6.0 to 10.0 μm, containing 15 to 40% by number of colorant-containing resin particles having a particle diameter of 5.0 μm or less, and having a particle diameter of 12.7 to 16.0 μm Particles containing 0.1-5.0% by volume, 16.0μ
1.0% by volume of colorant-containing resin particles having a particle size of at least m
The colorant-containing resin particles having a particle size of 6.35 to 10.1 μm containing A non-magnetic color toner having a particle size distribution satisfying the following.

Further, the present invention provides a method for forming a color toner image on an image carrier having a photoconductor having an organic semiconductor with a developer having a non-magnetic color toner, transferring the color toner image to a transfer material, An image forming method in which a residual image is cleaned by a counter blade cleaning means and a color image is formed by repeatedly using the image carrier. A) The loss coefficient of a rubber elastic material is used as the counter blade cleaning means. a) using a cleaning blade having a peak temperature of tan δ of 0 ° C. or less; B) controlling the surface temperature of the image carrier to 35 to 45 ° C .; and C) the nonmagnetic color toner comprises at least colorant-containing resin particles and At least one of the additives is a spherical titanium oxide having a volume average particle diameter of 0.05 to 2.0 μm produced by a sol-gel method. The spherical titanium oxide is contained in an amount of 0.03 to 3% by weight based on the colorant-containing resin particles, and the nonmagnetic color toner has a volume average particle diameter in a range of 6.0 to 10.0 μm, and a volume average particle diameter of 5.0 μm. Colorant-containing resin particles having the following particle size
Contains 5 to 40% by number, contains 0.1 to 5.0% by volume of colorant-containing resin particles having a particle size of 12.7 to 16.0 μm, and contains 1.0% by volume or less of colorant-containing resin particles having a particle size of 16.0 μm or more. The colorant-containing resin particles having a particle size of 6.35 to 10.1 μm have the following formula: And an image forming method characterized by having a particle size distribution satisfying the following.

The image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows a full-color electronic copying machine according to an embodiment of the present invention. The image carrier 1 is rotatably supported in the direction of the arrow, and is charged by the charger 2 and the exposure unit 3.
An electrostatic latent image is formed on the image. The latent image is stored in the rotary developing unit 4
4 developing units attached to the yellow developing unit
4Y, magenta developing device 4M, cyan developing device 4C, and any developing device among black developing device 4B, in FIG. 1, yellow developing device 4Y
Is developed and visualized.

The visible image (toner image) is transferred by a transfer charger 6 to a transfer material 8 held and conveyed on a transfer drum 5.

On the other hand, the residual toner on the image carrier 1 is cleaned by the cleaning unit 10 and is used for the next image forming process.

Thereafter, similarly, a toner image is formed on the image carrier 1,
The second color, the third color, and the fourth color toner images are transferred onto the same transfer material 8 in a superimposed manner. The transfer material 8 on which the multiple transfer is performed is separated from the transfer drum 5 by a separation charger 7, and is discharged outside the apparatus via a fixing device 9.

Since such a full-color image forming apparatus and method are well known to those skilled in the art, further detailed description will be omitted.

According to the present invention, the cleaning means 10 is a blade cleaning means having a cleaning blade 11. Although the cleaning blade 111 can be arranged in the forward direction with respect to the direction of movement of the image carrier 1, from the viewpoint of cleaning efficiency, it is arranged in the direction opposite to the direction of movement of the image carrier 1 as shown in the figure. Is preferred.

Using polyurethane as a cleaning blade,
The dynamic viscoelasticity data such as the loss coefficient tan δ, which was most correlated with the creep recovery of the rubber elastic body, was measured by using a rheopexy analyzer of Iwamoto Seisakusho.

As a measuring method, it is calculated by the following formula using a forced torsional vibration method.

The response torque (output) is measured by applying a torsional sinusoidal vibration (input) at a constant angle, and the dynamic viscoelasticity is obtained by each Fourier transform.

Angular displacement: θ ₀ , frequency: f ₀ = ω ₀ / 2π displacement θ (t) = θ ₀ exp (iω ₀ t) angular velocity Ω (t) = dθ (t) / dt = iω ₀ θ ₀ exp (iω ₀ t) Torque T (t) = T ₀ exp {i (ω ₀ t + δ)} Complex viscosity η ^* (= η′−iη ″) and various dynamic characteristics are obtained from the following equations. Means Fourier transform.

Loss coefficient tan δ = G ″ / G ′ A is a device constant and is obtained by a test fixture as follows.

A simple device diagram is shown in FIG.

Loss factor tan of the cleaning blade in the present invention
The cleaning method in which the peak temperature of δ is 0 ° C. or less and the surface temperature of the image carrier is controlled at 35 ° C. to 45 ° C. becomes more effective in the following toner combination. In addition,
In the following description regarding the particle size distribution of the toner, the “colorant-containing resin particles” are referred to as “toner particles”.

That is, in the present invention, the particle size distribution of the toner is also characterized for the purpose of achieving high image quality, and the non-magnetic color toner has a volume average particle size in the range of 6.0 to 10.0 μm,
15 to 40% by number of toner particles having a particle size of 1 μm or less, and 0.1 to 0.1% of toner particles having a particle size of 12.7 to 16.0 μm
It contains 5.0% by volume and contains 1.0% by volume or less of toner particles having a particle size of 16.0 μm or more, and the toner particles having a particle size of 6.35 to 10.1 μm are represented by the following formula: It is necessary to have a particle size distribution satisfying the following.

A color toner containing two or more inorganic oxides and having the above-described particle size distribution can reproduce faithfully a latent image formed on a photoreceptor, and has a small size such as a halftone dot and a digital image. It is also excellent in the reproduction of the dot latent image, and gives an image with particularly excellent gradation and resolution in the highlight portion. Furthermore, even when copying or printing out is continued, high image quality is maintained, and even in the case of a high-density image, good development can be performed with less toner consumption than conventional toner, and economical and This also has an advantage in reducing the size of the copying machine or the printer body.

The reason why such effects are obtained in the color toner used in the present invention is not necessarily clear, but is presumed as follows.

That is, one feature of the present invention is that the toner particles having a particle diameter of 5.0 μm or less are 15 to 40% by number. Conventionally, in a color toner, toner particles of 5.0 μm or less are difficult to control the charge amount, impair the fluidity of the toner, and as a component that scatters the toner and soils the machine, and further as a component that causes image fog. It has been considered that it is necessary to actively reduce the amount of components that cause poor cleaning.

However, according to the study of the present inventors, 5.0 μm
It has been found that a certain amount of toner particles are an essential component for forming a high quality image.

For example, using a two-component developer having a toner and a carrier having a particle size distribution ranging from 0.5 μm to 30.0 μm, the surface potential on the photoreceptor is changed, and a large development potential contrast from a large development potential contrast at which many toner particles are easily developed is obtained. Develop the latent image with the latent image potential changed on the photoreceptor to the latent image of small minute dots where only a few toner particles are developed to tone, collect the developed toner particles on the photoreceptor, and collect toner particles When the distribution was measured, it was found that there were many toner particles having a size of 8.0 μm or less, and in particular, toner particles having a size of about 5.0 μm were large on the latent image of fine dots. That is, 5.
When toner particles having a particle size of about 0 μm are smoothly supplied to the development of the latent image on the photoreceptor, the image is faithful to the latent image, and an image with excellent reproducibility can be obtained without protruding from the latent image. is there.

One feature of the present invention is that the toner particles in the range of 12.7 to 16.0 μm are 0.1 to 5.0% by volume.

This is related to the necessity of the above-mentioned toner particles having a particle size of about 5.0 μm, but the toner particles having a particle diameter of 5.0 μm or less certainly have the ability to faithfully reproduce a latent image of fine dots. However, the cohesiveness itself is considerably high, so that the fluidity as a toner may be impaired.

The present inventors have tried to improve the fluidity by adding an inorganic oxide for the purpose of improving the fluidity. However, only the means of adding the inorganic additive can reduce the image density, toner scattering, fog, etc. It was confirmed that the conditions for satisfying the above items were very narrow. Therefore, the present inventors further studied the particle size distribution of the toner, and found that 15 to 40% by number of toner particles having a particle size of 5.0 μm or less
It has been found that by containing toner particles of 2.7 to 16.0 μm in an amount of 0.1 to 5.0% by volume, the problem of fluidity can be solved and high image quality can be achieved. That is, it is considered that the toner particles in the range of 12.7 to 16.0 μm have a moderately controlled fluidity with respect to the toner particles of 5.0 μm or less, and as a result, even when copying or printing is continued, the toner particles have a high density. A sharp image with excellent resolution and gradation is provided.

Further, with respect to the toner particles of 6.35 to 10.1 μm, between the volume% (V), the number% (N) and the volume average particle size (v), Another feature is that the color toner of the present invention satisfies the following relationship.

The present inventors have only studied the state of the particle size distribution and the development characteristics, and have found that there is a state of existence of the particle size distribution suitable for achieving the most objective as shown by the above formula.

That is, when the particle size distribution is adjusted by general air classification, that the above value is large means that toner particles of about 5.0 μm that faithfully reproduces a minute dot latent image increase, and that the above value is small, Conversely, it is understood that toner particles of about 5.0 μm indicate a decrease.

Therefore, v is in the range of 6.0 to 10.0 μm, and
When the above relational expressions are further satisfied, good toner fluidity and faithful latent image reproducibility are achieved.

For toner particles having a particle diameter of 16.0 μm or more, 1.
It is preferable that the content is 0 volume% or less and the amount is as small as possible.

The configuration of the present invention will be described in more detail. In the present invention, the toner particles having a particle diameter of 5.0 μm or less account for 15 to 40% by number of the total number of toner particles, and preferably 20 to 35% by number. 15% by number of toner particles with particle size of less than 5.0μm
When the toner particle size is less than the effective toner particles for high image quality, particularly, as the toner is used by continuing to copy or print out, the effective toner particle component decreases and the particle size distribution of the toner as shown in the present invention is reduced. And the image quality gradually decreases. When the content exceeds 40% by number, non-magnetic toner particles tend to aggregate with each other,
Since the toner mass is larger than the original particle size, the image quality becomes rough, the resolution is reduced, or the density difference between the edge portion and the inside of the latent image is increased, so that the image layer tends to be hollow.

Further, the particle size in the range of 12.7 to 16.0 μm is 0.1 to 5.0% by volume, preferably 0.2 to 3.0% by volume. When the content is more than 5.0% by volume, the image quality is deteriorated, and the development is performed more than necessary, that is, the toner is excessively applied, which causes an increase in toner consumption. On the other hand, when the content is less than 0.1% by volume, the image density is reduced due to the decrease in fluidity.

Further, the content of toner particles having a particle size of 16.0 μm or less is 1.0% by volume or less, more preferably 0.6% by volume or less. The developed toner particles have coarse toner particles of 16.0 μm or more protruding on the thin layer surface, so the delicate state of contact between the photoconductor and the transfer paper via the toner layer is irregular, and the transfer is performed. This causes a change in the condition, which causes a transfer failure image. Further, the volume average diameter of the toner is 6.0 to 10.0 μm, preferably 7.0 to 9.0 μm
This value cannot be considered separately from the above-described components. Volume average particle size 6.0μ
If it is less than m, in applications where the image area ratio is high, such as graphic images, the amount of toner deposited on transfer paper is small, and the problem of low image density is likely to occur. This is considered to be due to the same reason as described above for lowering the density inside the edge portion of the latent image. Volume average particle size is 10.0
If it exceeds μm, the resolution is not good, and the image quality is liable to be deteriorated if the image is continuously used at the beginning of copying.

Although the particle size distribution of the toner can be measured by various methods, in the present invention, the measurement was performed using a Coulter counter.

That is, as a measuring device, Coulter Counter TA-II
Using an interface (manufactured by Nikkaki) and a CX-1 personal computer (manufactured by Canon Inc.) using a mold (manufactured by Coulter) and a CX-1 personal computer (manufactured by Canon), the electrolytic solution is 1% NaCl Prepare an aqueous solution. As a measuring method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersing agent to 100 to 150 ml of the electric field aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the Coulter Counter TA-II was used, and a 100 μm aperture was used as an aperture. Was measured, and the value according to the present invention was determined therefrom.

In the present invention, the toner having the above-described particle size distribution contains 0.03 to 3% by weight of a titanium oxide having a volume average particle diameter of 0.05 to 2.0 μm produced by a sol-gel method of at least one color as an inorganic oxide. There are features.

As described above, when the toner having the specific particle size distribution in the present invention is used, the toner development with respect to the latent image by the fine dots is faithful, and the disturbance of the toner adhesion at the edge of the latent image is small.

However, when the particle size of the toner is reduced, the Coulomb force and Van der Waals force acting on the toner become relatively stronger than the gravitational force and the inertia force, so that the adhesive force between the toners becomes stronger and toner aggregates are generated. At the same time, the adhesion to the photoreceptor is increased. Therefore, it is necessary that the cleaning blade is in strong contact with the photoconductor, but when the lubrication between the cleaning blade and the photoconductor is completely lost, the cleaning blade vibrates,
Alternatively, the blade may be turned up and the blade edge may be damaged.

However, in the present invention, the volume average particle size is 0.05 to 2.
Since the titanium oxide of 0 μm is contained in at least one color, the titanium oxide serves as a spacer particle between the cleaning blade and the photoconductor, and causes the cleaning blade and the photoconductor to be appropriately pressed against each other to remove the transfer residue. The toner is sufficiently cleaned to avoid image deterioration and the like due to uneven cleaning of the photoconductor due to poor cleaning or fluctuation in torque due to cleaning.

In the present invention, the titanium fine powder may be added to at least one of the four colors because the titanium fine powder appropriately remains at the blade edge portion. However, the frictional resistance between the cleaning blade and the photosensitive member is particularly large at startup. For this reason, it is more effective to add the fourth color in the developing order and to positively leave it at the blade edge.

As the 0.05 to 2.0 μm titanium oxide that can be used in the present invention, a spherical titanium oxide produced by a sol-gel method is preferable.

Furthermore, 80% or more in the volume distribution is ± 30% of the average particle size.
It is desirable to be within.

If the above-mentioned inorganic oxide is smaller than 0.05 μm, the particles are more likely to pass through the cleaning blade and hardly accumulate at the edge of the cleaning blade, and the effect as spacer particles is shortened. This causes adverse effects such as abrasion.

On the other hand, if it is larger than 2.0 μm, cleaning is sufficiently performed at the edge of the cleaning blade, and it is difficult for the cleaning blade to collect at the edge of the cleaning blade, so that the effect as spacer particles is lost.

In the present invention, if necessary, an inorganic oxide as a fluidity improver or an inorganic oxide as a charge stabilizer may be added.

As the inorganic oxide as a fluidity improver, any inorganic oxide having a specific surface area of 80 m ² / g or more may be used, but as a preferred example, silica fine powder produced by gas phase oxidation of a silicon halide compound It is more preferable to use a treated silica fine powder subjected to a hydrophobic treatment. It is particularly preferable that the treated silica fine powder is obtained by treating the silica fine powder such that the degree of hydrophobicity measured by a methanol titration test shows a value in the range of 30 to 80.

Hydrophobization is applied by reacting with silica fine powder or chemically treating it with an organic silicon compound that physically adsorbs.

As a preferred method, silica fine powder produced by vapor phase oxidation of a silicon halide is treated with an organosilicon compound.

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane,
Trimethylethoxysilane, dimethyldichlorosilane,
Methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α
-Chloroethylchlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane,
Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and 2 to 12 siloxane units per molecule, one for each terminal unit Examples include dimethylpolysiloxane containing a hydroxyl group bonded to Si.
These are used in one kind or in a mixture of two or more kinds.

The particle size of the treated silica fine powder is 0.003-0.1μm
It is preferable to use those in the range of Commercial products include Taranox-500 (Talco), Aerosil (AER
OSIL) R-972 (Nippon Aerosil Co., Ltd.).

 The measurement of the degree of hydrophobicity in the present invention was performed as follows.

Hydrophobicity measurement: The methanol titration test is an experimental test for confirming the hydrophobicity of fine silica powder having a hydrophobized surface.

In order to evaluate the degree of hydrophobicity of the treated fine silica powder, the "methanol titration test" defined in the present specification is performed as follows. 0.2 g of the test silica fine powder is added to 50 ml of water in a 250 ml Erlenmeyer flask. Methanol is titrated from the burette until all of the silica is wetted. At this time, the solution in the flask is constantly stirred with a magneck stirrer. The end point is observed as the entire amount of fine silica powder is suspended in the liquid, and the degree of hydrophobicity is expressed as the percentage of methanol in the liquid mixture of methanol and water when the end point is reached.

On the other hand, as the inorganic oxide as a charge stabilizer, alumina and titanium oxide are preferable because they can easily obtain a sharp particle size by a gas phase method, but there are no particular restrictions on the production method and crystal structure. . However, it is not preferable that the particles have an extremely square shape or needle shape.

As the binder used for the colorant-containing resin particles contained in the toner used in the present invention, various material resins conventionally known as toner binder resins for electrophotography are used.

For example, styrene-based copolymers such as polystyrene, styrene-butadiene copolymer, styrene-acrylic copolymer, and ethylene-based copolymers such as polyethylene, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer Phenolic resin, epoxy resin, acrylic phthalate resin, polyamide resin, polyester resin, maleic acid resin and the like. In addition, the production method of any resin is not particularly limited.

The effect of the present invention is remarkable when a polyester resin having a high negative power is used among these resins. In other words, while the polyester resin has excellent fixability and is suitable for a color toner, the negative charging ability is strong and the charging is liable to be excessive, but the adverse effect of using the polyester resin in the constitution of the present invention is improved, and an excellent toner is obtained. Can be

In particular, (Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 2)
It is 10. A) a carboxylic acid component composed of a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, phthalic acid) Acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) are more preferred because they have sharp melting properties.

In particular, from the viewpoint of light transmission with a trapene, the apparent viscosity at 90 ° C. is 5 × 10 ^{4 to} 5 × 10 ⁶ poise, preferably 7.5 × 10 ⁴ poise.
２2 × 10 ⁶ poise, more preferably 10 ⁵ to 10 ⁶ poise, and the apparent viscosity at 100 ° C. is 10 ^{4 to} 5 × 10 ⁵ poise, preferably 10 ^{4 to} 3 × 10 ⁵ poise, more preferably 10 ⁴ to 2
Color O with good light transmittance due to × 10 ⁵ poise
As a result, good results can be obtained in fixing property, color mixing property and high-temperature offset resistance as a full-color toner. 90 ℃
The absolute value of the difference between the apparent viscosity P ₂ at apparent viscosity P ₁ and 100 ° C. in ^{the, 2 × 10 5 <| P} 1 -P 2 | < particularly preferably in the range of 4 × 10 ^6.

As the coloring agent, known dyes and pigments, for example, phthalocyanine blue, indasulene blue, peacock blue, permanent red, lake red, rhodamine lake,
It can be widely used such as Hansa Yellow, Permanent Yellow and Benzicin Yellow. The content thereof is 12 parts by weight or less, preferably 0.5 to 9 parts by weight, based on 100 parts by weight of the binder resin so as to be sensitive to the light transmittance of the OHP film.

The toner according to the present invention may contain a charge control agent for stabilizing the charge characteristics. At that time, a colorless or light-colored charge control agent that does not affect the color tone of the toner is preferable. In the present invention, when a negatively charged developer is used, the present invention is more effective. In this case, as the negatively charge controlling agent, for example, a metal complex of an alkyl-substituted salicylic acid (for example, di-
organometallic complexes such as chromium or zinc complexes of tert-butylsalicylic acid). When the negative charge control agent is blended in the toner, 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin.
It is preferable to add 0.5 parts by weight, preferably 0.5 to 8 parts by weight.
The toner of the present invention can be applied to both the one-component developing method and the two-component developing method. In the case of the two-component developing method, the magnetic particles used as the carrier include, for example, surface-oxidized or unoxidized iron, nickel, copper, zinc, cobalt, manganese, chromium, metals such as rare earths, and alloys or oxides thereof. Ferrite or the like can be used. Also, there is no particular restriction on the manufacturing method.

In the present invention, the surface of the magnetic particles is coated with a resin or the like.A method of dissolving or suspending a coating material such as a resin in a solvent and applying the coating material to adhere to the magnetic particles, or simply a powder method Any of the conventionally known methods, such as a method of mixing with, for example, can be applied. In order to stabilize the coating layer, it is preferable that the coating material be dissolved in a solvent.

The coating material on the surface of the magnetic particles varies depending on the toner material, for example, amino acrylate resin,
Acrylic resins or copolymers of these resins with styrene resins are preferred. As a negatively charged resin,
Silicone resin, polyester resin, polytetrafluoroethylene, monochlorotrifluoroethylene polymer,
Polyvinylidene fluoride and the like are suitable, but are not necessarily limited thereto.

What is most suitable for the present invention is an acrylic resin or a copolymer of such a resin with a styrene resin.

The most suitable material for the magnetic particles used in the present invention is 98% or more of Cu—Zn—Fe (composition ratio (5 to 20): (5 to 20%).
20): Ferrite particles having a composition of (30 to 80)), which are easy to smoothen the surface and have a stable charging ability,
In addition, the coat can be stabilized.

The amount of the compound to be coated may be appropriately determined so that the charge imparting property of the magnetic particles satisfies the above-described conditions, but is generally 0.1 to 30% by weight (preferably 0.3 to 30% by weight) based on the magnetic particles of the present invention. 20% by weight).

These magnetic particles preferably have a weight average particle size of 35.0 to 65.0 μm, preferably 40.0 to 60.0 μm. Further, the weight distribution of 26.0 μm or less is 2 to 6%, and the weight distribution of 35.0 μm to 43.0 μm is 5% or more and 25% or less,
In addition, when 74.0 μm or less is 2% or less, a good image can be maintained.

In the present invention, when the mixing ratio of the magnetic particles and the toner particles is 2 to 9% by weight, preferably 3 to 8% by weight as the toner concentration in the developer, generally good results can be obtained. If the toner concentration is less than 2% by weight, the image density is too low to be practical, and if it is more than 9% by weight, fog and scattering inside the machine are increased, and the useful life of the developer is shortened.

Further, in the present invention, a fatty acid metal salt as a lubricant,
For example, zinc stearate, aluminum stearate, etc., or
Fine powder of a fluorine-containing polymer, for example, polytetrafluoroethylene, polyvinylidene fluoride, etc. and a fine powder of a tetrafluoroethylene-vinylidene fluoride copolymer, or a conductivity imparting agent such as tin oxide, zinc oxide, etc. May be.

In the present invention, in order to produce the colorant-containing resin particles contained in the toner, a thermoplastic resin is used, if necessary, by adding a pigment or dye as a colorant, a charge control agent, and other additives to a mixer such as a ball mill. After mixing, using a hot kneader such as a heating roll, kneader or extruder, the resin or pigment is melted, kneaded and kneaded to disperse or disperse the pigment or dye in the resin, and then cooled and solidified. By performing pulverization and strict classification, the colorant-containing resin particles according to the present invention can be obtained.

[Examples] Hereinafter, "parts" all indicate parts by weight.

Example 1 The above compound was sufficiently premixed with a Henschel mixer, melt-kneaded at least twice with a three-roll mill, cooled, and coarsely ground to a particle size of about 1 to 2 mm using a hammer mill. Next, it was pulverized by a pulverizer using an air jet method. Further, the obtained finely pulverized product was classified by a multi-segment classifier to obtain yellow resin particles.

100 parts of the colorant-containing resin particles have a specific surface area of 100 m ² / g by the BET method.
And 0.5 part of silica fine powder having a specific surface area of 250 m ² / g by BET method and a hydrophobicity of -80 μc / g treated with hydrophobization with hexamethyldisilazane were added to obtain a yellow toner. The volume average particle size of this toner is 8.0μm,
36% by number, V × v / N was 13.7.

Next, magenta resin particles were obtained by using 4 parts of a rhodamine pigment instead of CI Pigment Yellow 17.

0.2 parts of alumina fine powder in the magenta resin particles,
0.5 part of the silica fine powder was added and externally added to obtain a magenta toner. The v of the toner was 8.5 μm, 17% by number was 5.0 μm or less, and V × v / N was 10.5.

Next, cyan resin particles were obtained using 5 parts of a phthalocyanine pigment instead of CI Pigment Yellow 17.

0.3 parts of alumina fine powder and 0.5 parts of silica fine powder were combined and externally added to the cyan resin particles to obtain a cyan toner.
V = 8.3 μm, 5.0 μm or less of this toner is 25% by number, V ×
v / N was 12.1.

Next, instead of CI Pigment Yellow 17, 1.2 parts of CI Pigment Yellow 17 and CI Pigment Red 5
Using 2.8 parts of CI Pigment Blue 15 and 1.5 parts of CI Pigment Blue 15, black resin particles were obtained.

The black resin particles have a particle size of 0.5 μm and a specific surface area of 150 m ^2.
A 0.5 g / g sol-gel method of spherical titanium oxide and 0.5 part of silica fine powder were combined and externally added to obtain a black toner. The v of this toner was 10.2 μm, 12.6 number% was 5.0 μm or less, and V × v / N was 9.9.

The above-mentioned Cu-Zn-Fe-based ferrite particles whose surfaces are coated with yellow, magenta, cyan, and black toners with a styrene-methyl methacrylate-2-ethylhexyl acrylate copolymer have toner concentrations of 5%, 5%, and 5%, respectively. , 7
% To obtain a developer.

Using this developer, the color order is set so that the development order is magenta, cyan, yellow, and black, and the peak temperature of tan δ is -3 ° C. on a commercially available plain paper copying machine (CLC-500, manufactured by Canon Inc.). Using a cleaning blade, the photoreceptor surface temperature was set to 38 ° C, and running tests of 20,000 sheets were performed at room temperature and normal humidity (23 ° C / 60% RH), and at low temperature and low humidity (15 ° C / 10% R).
H), high-temperature and high-humidity (32.5 ° C./90% RH) environment. As a result, a high-quality image with sufficient image density and free from defects such as poor cleaning was obtained in any environment.

Comparative Example 1 The same operation as in Example 1 was carried out except that titanium oxide was not used as the black toner.
Under / 90%, cleaning failure occurred at the time of 500 sheets, which is considered to be caused by the edge of the blade.

Therefore, when the temperature and humidity were lowered to 30 ° C./80%, the cleaning failure was eliminated.

Comparative Example 2 In Example 1, the same procedure as in Example 1 was carried out except that a blade having a peak temperature of tan δ of 20 ° C. was used as a cleaning blade by changing the ratio of isocyanate to polytetramethylene glycol. 15 ℃ / 10
% Cleaning failure occurred at 2,000 sheets due to paper dust jam.

Comparative Example 3 The procedure of Example 1 was repeated, except that the amorphous titanium oxide having a thickness of 1.5 μm and 400 m ² / g was used as the titanium oxide in the black toner by a liquid phase method.
Cleaning failure occurred at 2.5 ° C / 90%.

Comparative Example 4 The spherical titanium oxide used in Example 1 was sintered to 3.0 μm.
When the same procedure was performed as in Example 1 except that 2 parts of the titanium oxide was used for the black toner, the cleaning blade edge was damaged at 3000 sheets, and cleaning failure occurred.

Comparative Example 5 Example 1 was repeated except that a non-spherical titanium oxide (P-25 manufactured by Nippon Aerosil Co., Ltd.) in which primary particles formed by a gas phase method were aggregated as a titanium oxide in a black toner was used. 32.5 ° C / 90
% Cleaning failure occurred at 2,000 sheets, which is considered to be caused by blade mark. In addition, 400 at 15 ℃ / 10%
At the time of 0 sheets, the edge of the cleaning blade was scratched, resulting in poor cleaning.

Example 2 In Example 1, the black toner was 0.2 μm and the specific surface area was 2
A good result was obtained by performing the same procedure as in Example 1 except that a titanium oxide containing 70% of rutile type and 30% of anatase type at 00 m ² / g was used.

[Effects of the Invention] As described above, according to the present invention, a high-quality image can be stably supplied for a long time under any environment.

[Brief description of the drawings]

FIG. 1 is a schematic view of a full-color electronic copying machine according to one embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the temperature of an image carrier and a friction coefficient, and FIG. 3 is an apparatus for determining tan δ in the present invention. FIG. 1: Image carrier, 2: Charger 3: Exposure means, 4: Rotary developing unit 4Y: Yellow developing device, 4M: Magenta developing device 4C: Cyan developing device, 4B: Black developing device 5: Transfer drum, 6: Transfer Charger 7: Separate charger, 8: Transfer material 9: Fixer, 10: Cleaning means 11: Cleaning blade

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G03G 15/08 507 G03G 9/08 381 361

Claims (6)

(57) [Claims] 1. A non-magnetic color toner having at least colorant-containing resin particles and two or more additives, wherein at least one of the additives has a spherical average particle diameter of 0.05 to 2.0 μm produced by a sol-gel method. Wherein the spherical titanium oxide is contained in an amount of 0.03 to 3% by weight based on the colorant-containing resin particles, and the nonmagnetic color toner has a volume average particle diameter of 6.0 to 10.0 μm. Within the range, containing 15 to 40% by number of colorant-containing resin particles having a particle size of 5.0 μm or less, containing 0.1 to 5.0% by volume of the colorant-containing resin particles having a particle size of 12.7 to 16.0 μm, 16.0μ
1.0% by volume of colorant-containing resin particles having a particle size of at least m
The colorant-containing resin particles having a particle size of 6.35 to 10.1 μm containing A nonmagnetic color toner having a particle size distribution satisfying the following. 2. The additive comprises an inorganic oxide having a particle size of 0.1 μm or less as a fluidity improver together with the spherical titanium oxide.
2. The non-magnetic color toner according to claim 1, wherein the non-magnetic color toner is contained in an amount of from 2 to 2% by weight. 3. A color toner image is formed on an image carrier having a photoreceptor having an organic semiconductor with a developer having a non-magnetic color toner, and the color toner image is transferred to a transfer material. And a color image is formed by repeatedly using the image bearing member to form a color image. A) The counter blade cleaning means includes a loss coefficient tan δ of a rubber elastic material. B) controlling the surface temperature of the image carrier to 35 to 45 ° C., and C) the nonmagnetic color toner comprises at least colorant-containing resin particles and two kinds of It has the above additive, and at least one of the additives is a spherical titanium oxide having a volume average particle diameter of 0.05 to 2.0 μm produced by a sol-gel method, Is contained in an amount of 0.03 to 3% by weight based on the colorant-containing resin particles, and the non-magnetic color toner has a volume average particle diameter in a range of 6.0 to 10.0 μm, and a volume average particle diameter of 5.0 μm or less. Colorant-containing resin particles having a particle size of 1
Contains 5 to 40% by number, contains 0.1 to 5.0% by volume of colorant-containing resin particles having a particle size of 12.7 to 16.0 μm, and contains 1.0% by volume or less of colorant-containing resin particles having a particle size of 16.0 μm or more. The colorant-containing resin particles having a particle size of 6.35 to 10.1 μm have the following formula: An image forming method characterized by having a particle size distribution satisfying the following. 4. A non-magnetic yellow toner having a colorant-containing resin particle containing a yellow colorant and two or more additives, a colorant-containing resin particle containing a magenta colorant and two or more additives. Non-magnetic magenta toner having a colorant, non-magnetic cyan toner having a colorant-containing resin particle containing a cyan colorant and two or more additives, and containing a yellow colorant, a magenta colorant and a cyan colorant A non-magnetic black toner having colorant-containing resin particles and two or more additives is used. On the transfer material, a yellow toner image, a magenta toner image,
An image forming method for forming a full-color image by multiple transfer of a cyan toner image and a black toner image, wherein the non-magnetic yellow toner, the non-magnetic magenta toner, the non-magnetic cyan toner and the non-magnetic black toner all have a volume average particle size. The diameter is in the range of 6.0 to 10.0 μm,
Colorant-containing resin particles having a particle size of 5.0 μm or less 15-4
0% by number, containing 0.1 to 5.0% by volume of colorant-containing resin particles having a particle size of 12.7 to 16.0 μm, and containing 1.0% by volume or less of colorant-containing resin particles having a particle size of 16.0 μm or more. The colorant-containing resin particles having a particle size of 6.35 to 10.1 μm have the following formula: Wherein the non-magnetic yellow toner, the non-magnetic magenta toner, the non-magnetic cyan toner and the non-magnetic black toner have at least one non-magnetic color toner selected from the group consisting of the additive Is a spherical titanium oxide having a volume average particle diameter of 0.05 to 2.0 μm produced by a sol-gel method, wherein the spherical titanium oxide is contained in an amount of 0.03 to 3% by weight based on the colorant-containing resin particles. 4. The image forming method according to claim 3, wherein the image is contained. 5. The image forming method according to claim 4, wherein the non-magnetic color toner of the final color formed on the image carrier contains the spherical titanium oxide. 6. The additive comprises an inorganic oxide having a particle size of 0.1 μm or less as a fluidity improver together with the spherical titanium oxide.
The image forming method according to any one of claims 3 to 5, wherein the content is from 2 to 2% by weight.