JP2005308925A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method by which color images of high image quality and high grade can stably be formed over a prolonged period of time, and in which excellent transferring and cleaning performances can be ensured. <P>SOLUTION: In the image forming method including at least an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic charge image carrier; a developing step of forming a toner image by developing the electrostatic latent image with a toner-containing developer; a transfer step of transferring the toner image onto a transfer member; and a fixing step of heat-fixing the toner image on a surface of a recording medium, a contact angle of a surface of the electrostatic charge image carrier to water is ≥95°, a surface toughness Rz thereof is ≤2 μm, and a small diameter side particle size distribution of number average particle diameter of the toner is ≤1.24. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an image forming method and an image forming apparatus using a process of developing an electrostatic latent image formed by an electrophotographic method or an electrostatic recording method with a developer.

A method for visualizing image information through an electrostatic latent image such as electrophotography is currently used in various fields such as a copying machine and a printer with the development of the technology and the expansion of market demand.
In electrophotography, an electrostatic charge image is formed on a photoreceptor by charging and exposure processes, the electrostatic latent image is developed with a developer containing toner, and visualized through a transfer / fixing process. The developer used here includes a two-component developer composed of a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone.

The toner is usually produced by a kneading and pulverizing method in which a thermoplastic resin is melt-kneaded together with a pigment, a charge control agent, a release agent, etc., cooled, finely pulverized, and further classified. For example, inorganic and organic fine particles for improving fluidity and cleaning properties may be added to the toner particle surfaces.
In the ordinary kneading and pulverizing method, the toner shape and the surface structure of the toner are indeterminate, and the toner shape and surface structure are intentionally difficult to control because they vary slightly depending on the pulverization properties of the materials used and the conditions of the pulverization process. is there. In particular, in the case of a material having a high pulverization property, the generation of fine powder or a change in toner shape is often caused by mechanical force in the developing machine.
Due to these effects, in the two-component developer, the charging deterioration of the developer is accelerated by the adhesion of fine powder to the carrier surface, and in the one-component developer, the toner scattering occurs due to the expansion of the particle size distribution, and the toner shape Deterioration in developability due to change tends to cause image quality degradation.

In addition, when a toner such as a wax is internally added to form a toner, the release agent is exposed to the surface in combination with a thermoplastic resin, which often affects reliability and the like. In particular, in the case of a combination of a resin imparted with elasticity by a high molecular weight component and slightly pulverized resin and a brittle wax-type release agent such as polyethylene, a large amount of polyethylene is exposed on the toner surface.
These are advantageous for releasability during fixing and cleaning of untransferred toner from the surface of the photoreceptor, but because the polyethylene on the surface layer is easily transferred by mechanical force, contamination of the developing roll, photoreceptor and carrier is prevented. It tends to occur, leading to a decrease in reliability.

In addition, since the toner shape is irregular, the fluidity is not sufficient even when a flow aid is added, and the fine particles on the toner surface move to the concave portions due to the action of mechanical force during use. As the fluidity decreases with time and the fluidity aid is buried in the toner, the developability, transferability, and cleaning properties deteriorate.
Further, when the toner collected by cleaning is returned to the developing machine and used again, the image quality is likely to further deteriorate. If the flow aid is further increased in order to prevent these problems, black spots are generated on the photoconductor and the aid particles are scattered.

In recent years, a toner production method using an emulsion polymerization aggregation method as a method for intentionally controlling the toner shape and the surface structure has been proposed (see, for example, Patent Documents 1 and 2).
In the emulsion polymerization aggregation method, since a finely divided raw material having a particle diameter of 1 μm or less is usually used as a starting material, a small-diameter toner can be efficiently produced in principle. More specifically, this method generally produces a resin dispersion by emulsion polymerization or the like, while producing a colorant dispersion in which a colorant is dispersed in a solvent, and mixes these resin dispersion and colorant dispersion. Then, aggregated particles corresponding to the toner particle diameter are formed, and then the aggregated particles are fused and united by heating to obtain a toner.

Usually, in such a toner production method, the surface and the interior of the obtained toner have the same composition, and it is difficult to intentionally control the surface composition. However, in order to solve this problem, a means to realize more precise particle structure control by freely controlling the toner from the inner layer to the surface layer when the toner is produced by the emulsion polymerization aggregation method is proposed. (See Patent Document 3).
The image quality of conventional electrophotographic images is dramatically improved by forming an image using the toner obtained by the toner production method capable of easily reducing the diameter of the toner and controlling the particle structure precisely. In addition, it has become possible to achieve both high reliability and high reliability.

On the other hand, in recent years, the image forming method by electrophotography using the toner / developer technology as described above has begun to be applied to a part of the printing area due to the progress of digitization and colorization, and the on-demand printing has been started. Practical use in the graphic arts market is beginning to become remarkable.
The graphic arts market refers to the overall printed market related to the production of printed materials such as prints, printed copies with a small number of copies, and the original copying, copying, and re-production of handwriting and paintings. It is defined as a market that targets industries and sectors related to the production of printed materials.

  For example, in the short run printing market, technology targeting not only monochrome printing but also the short run color market represented by Fuji Xerox ColorDoctech 60 has been developed by taking advantage of the characteristics of plateless printing in electrophotography. A great progress is being made in terms of paper compatibility, product price, and price per sheet (see Non-Patent Document 1).

  However, plateless printing in electrophotography is typified by its color gamut, resolution, and gloss characteristics, although it has on-demand characteristics as plateless printing when compared to original full-scale conventional printing. Image quality, texture, image uniformity in the same image, maintainability of image quality during long continuous printing, high price per sheet due to toner consumption at high image density, compatibility with thinner and thicker paper, Image defects caused by oil during image fixing, poor writing performance, high power consumption due to high-temperature fixing at high speed, paper elongation, curl, wave, and registration marks on both sides due to image fixing at high temperature and pressure This is likely to cause problems.

In principle, a toner image composed of a low-molecular resin having a relatively low softening point is thermally fixed, so the heat and mechanical durability of the image may be weaker than the printed image. When booked or bound in multiple layers and exposed to high temperatures under high load conditions, there will be problems with durability against various stresses such as image loss, blocking, offset, light resistance due to outdoor exposure, weather resistance, etc. There is a case.
In this way, it has become clear that there are still a number of issues to fully replace conventional printing with plateless printing in electrophotography and to promote market value as a production product, especially in the graphic arts domain. Yes.

  Regarding the color reproduction region, the types of pigments actually used in the electrophotographic region are smaller than the types used in the original conventional printing ink, and further high-performance colorant technology is required. Since the usage conditions in the graphic arts range are broad compared to the office market, not only high color reproducibility but also various durability such as heat resistance, light resistance, water resistance, oil resistance, solvent resistance, scratch resistance, and bending strength Sexuality will be required.

  The resolution is easily limited by the particle size and distribution of the toner in all image processing systems, photoconductors, and exposure systems, but it is effective and reliable in each process such as charging, developing, transferring, fixing, and cleaning of small-diameter toner. There is a big technical problem to use high.

  For example, a carrier for uniformly charging small-diameter toner, a design of a charging blade or a charging roll, a development system that obtains a high image density without causing background contamination, a transfer system that realizes transfer with fine and high transfer efficiency, There are a fixing system corresponding to a combination of a small-diameter toner and various types of paper, and a cleaning system that completely removes the small-diameter toner from the photosensitive member or the intermediate transfer member to realize a stable image quality.

  In order to improve the in-plane uniformity and defects of the image, it is important to control the uniformity of the developing ability of the developer in the image forming system. To meet the demands of the printing market for maintaining image quality, stable and uniform development is maintained even with continuous printing of thousands of sheets, and stable development is maintained, and highly durable development with little environmental dependency on temperature, humidity, etc. An agent is needed. Furthermore, it is necessary to optimize the developing system so that the influence of paper dust and foreign matters can be avoided, the durability is high, defects and noise are hardly generated, and the in-plane density of the image can be maintained uniformly.

  In a system for transferring a toner image from a photosensitive member or an intermediate transfer member to a transfer target, an electrostatic transfer system is generally used in the current electrophotographic method. However, in the case of a color image in which the toner image thickness increases due to color superposition, it is required to precisely control the behavior of the toner in the electric field in order to suppress image deterioration due to toner scattering during transfer. Such controllability needs to be optimized from the toner material side and the transfer system side. Further, depending on the case, a transfer system that can drastically suppress toner scattering, such as adhesive transfer, is required.

  As a cleaning system, together with a highly durable photoconductor, a blade, an electrostatic brush, a magnetic brush, a web, and a simultaneous development cleaning method are used to continuously and reliably and reliably control toner having a small diameter and a spherical shape. It is important to optimize the cleaning system without depending on the environment from the toner material, structure and hardware system.

  For the price per sheet, it is necessary to reduce the toner consumption by reducing the diameter of the toner and optimizing the amount of the colorant, which also tends to affect the uniformity of the image quality. By realizing an image forming system with high reliability by the means described above, it is possible to reduce the drastic influence (disappearance output for obtaining stable image quality) in printing and to reduce maintenance load. In practice, it is also important to reduce the price per sheet.

In order to handle thin paper and thick paper, it is easy to peel off the paper from the fixing member such as a fixing roll after fixing, even if the paper is thin paper such as thin paper or plastic film, Toner materials that can be fixed at low temperature, which can suppress power consumption even when fixing coated paper or cardboard, are essential. Fixing at a low temperature or low pressure can reduce the stress on the paper, suppress the paper stretch, curl and wave, and can solve problems such as misregistration.
Further, in order to avoid image defects such as stains and streaks due to oil and poor writability, an oilless fixing device and a toner capable of oilless fixing containing a release material inside the toner are required.

  In addition, in order to achieve image durability that is comparable to normal printed images and does not cause problems under various usage conditions, the resin properties used in conventional toners must be further improved. I must.

  In order to make the gloss characteristics of an image more flexible and uniform, it is important to optimize the fixing device as well as control the viscoelasticity of the toner. In order to obtain a high-quality image based on offset printing, it is important to increase the market value to achieve the optimum gloss for the paper used. Is necessary.

  Furthermore, a feature that has recently been promoted in fields such as on-demand printing is its environmental load performance. Reduce the environmental burden associated with inventory, movement, and disposal of printed materials that are likely to occur during normal printing by eliminating or minimizing inventory by on-demand printing operations via the network it can. In addition, since the organic solvent used in the ink used in a normal printing machine is not used in the dry toner used in normal electrophotography, the environmental burden associated with VOC can be fundamentally reduced.

  However, for further improvement, not only the reduction of electrical energy associated with image fixing and hardware conditioning, but also the odor and volatile content from the heated and melted resin generated during fixing, and the small toner component Controlling external emissions is also an important issue. It is also necessary to consider the recyclability of discarded toner and printing paper.

  As described above, in order to meet the demands of the graphic arts market and the short run market (which may be called the light printing market), it is necessary to develop a technology that further develops the conventional electrophotographic technology as a system. ing.

  The reduction in toner diameter is advantageous in that high image quality with high resolution can be obtained, toner consumption can be reduced, and the price per sheet can be reduced. Such a small-diameter toner can be easily obtained by using the emulsion polymerization aggregation method described above, and a small-diameter toner having a particle diameter of 5 μm or less, which was difficult to obtain by the conventional kneading and pulverizing method, can be easily obtained. Can do.

However, the small-diameter toner is disadvantageous from the viewpoint of transferability and cleaning properties due to its high adhesion, and often causes a decrease in reliability.
Specifically, the transfer efficiency decreases, resulting in an increase in residual toner on the photoconductor and intermediate transfer body, and uneven image density and image defects due to poor transferability to rough paper with low surface smoothness. Become. Further, in a cleaning system using a blade or the like, sufficient cleaning cannot be performed due to abrasion from the blade, and image defects due to poor cleaning, background stains, streaks, and the like may occur. In particular, these deteriorations in image quality are often seen during continuous running.

  In order to control the transferability and cleaning performance of such a small diameter toner, it is effective to reduce the adherence of the toner to the photoreceptor or intermediate transfer body. For example, in conventional toners, inorganic or organic fine particles (hereinafter sometimes abbreviated as “external additives”) are usually adhered to the surface of toner particles, and the effect of these fine particle external additives is used. Reduces toner adhesion.

  However, these external additives added to the toner surface are constantly subjected to mechanical stress in the developing machine, transfer unit, cleaning unit, etc. under the use of copying machines, printers, etc. The toner adheres to the inside of the toner from the inside or the external additive is detached from the toner surface, so that the adhesion of the toner increases over time, which reduces the transfer efficiency and deteriorates the cleaning performance. It will cause a decline.

In order to prevent such a decrease in reliability over time, it is known that reducing the surface energy of the photoreceptor is effective. For example, attempts have been made to improve cleaning reliability and transferability deterioration by using a composition having fluorine or silicon as a constituent material of the surface layer of the photoreceptor and reducing the surface energy of the photoreceptor. (For example, see Patent Document 4).
Japanese Patent Laid-Open No. 63-282275 JP-A-6-250439 Japanese Patent No. 3141784 JP-A-7-84394 Journal of the Imaging Society of Japan Vol. 40 No. 2 (2001)

However, as a result of intensive studies by the present inventors, as described above, even when using a toner to which an external additive is added or using a photoconductor whose surface has a low surface energy, the diameter of the toner to be used is reduced. Accompanying this, it was confirmed that it was difficult to prevent a decrease in reliability over time.
An object of the present invention is to solve the above problems. That is, the present invention provides an image forming method capable of forming a high-quality and high-quality color image stably over a long period of time, and obtaining excellent transferability and cleaning properties, and an image forming apparatus using the same. This is the issue.

In order to solve the above-described problems, the present inventors diligently studied the cause of unavoidable deterioration in reliability over time as the diameter of the toner is reduced.
For this reason, first, when the image formation is performed by using the toner having a smaller diameter than the conventional one, the inventors have observed what peculiar phenomenon occurs as compared with the toner having the conventional particle diameter. We investigated whether it was.

  As a result, in particular, when an image is formed by an image forming apparatus provided with a cleaning blade as a cleaning unit using toner whose diameter is reduced so that the volume average particle diameter is 6 μm or less, first, a toner image is formed. The toner remaining on the surface of the photoconductor (electrostatic charge image carrier) after the transfer has a relatively smaller diameter and a lot of irregularly shaped toner compared to the original toner. It was confirmed that image formation defects such as dirt were likely to occur, and thirdly, image defects such as black spots were likely to occur.

  Here, from the first result, in order to continue to maintain high reliability in terms of cleaning performance and transfer performance for a long period of time even when a toner having a smaller diameter is used, the present inventors In addition to minimizing the fine powder side component of the particle size distribution of the toner that tends to remain on the photoreceptor after the image is transferred (hereinafter sometimes abbreviated as “fine toner”), it is contained in the residual fine toner. It was considered indispensable to reduce the small diameter component (hereinafter sometimes abbreviated as “ultrafine toner”).

The second result is that a slight gap in the nip portion between the cleaning blade and the photosensitive member, which could not pass when image formation was performed using a toner having a conventional particle size, and the blade nip pressure was weak. It is considered that the region suggests that the fine toner is easily slipped through.
In addition, the third result is considered to be because the fine toner having a higher adhesion force stuck to the rough portion of the surface of the photosensitive member without being removed and remaining.
From these results, the present inventors reduced the slight clearance of the nip part and the blade nip pressure unevenness in the nip part to prevent the fine toner from slipping through and prevent the fine toner from adhering to the surface of the photoreceptor. I thought it was important to make it difficult to happen.
Based on the above findings, the present inventors have found the following present invention. That is, the present invention

<1>
An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic image carrier, a developing step of developing the electrostatic latent image with a developer containing toner to form a toner image, and the toner image In an image forming method comprising at least a transfer step of transferring onto a transfer body, and a fixing step of thermally fixing the toner image to a recording medium surface,
A contact angle with respect to water of the surface of the electrostatic charge image bearing member is 95 degrees or more, a surface roughness Rz is 2 μm or less, and a small diameter side particle size distribution of the number average particle diameter of the toner is 1.24 or less. This is an image forming method.

<2>
The toner is produced through at least a coagulation step of aggregating the particles in a dispersion in which particles containing at least resin particles are dispersed to obtain aggregated particles and a fusion step of fusing the aggregated particles by heating. The image forming method according to <1>, wherein the image forming method is manufactured.

<3>
The image forming method according to <1>, wherein the toner has a volume average particle diameter of 5 μm or less.

<4>
The image forming method according to <1>, wherein the developer includes the toner and a carrier.

<5>
An electrostatic image carrier, an exposure unit that forms an electrostatic latent image on the surface of the electrostatic image carrier, a developing unit that develops the electrostatic latent image with a developer containing toner, and a toner image; In an image forming apparatus comprising at least a transfer unit that transfers the toner image on the surface of the electrostatic image carrier onto a transfer member, and a fixing unit that thermally fixes the toner image on a recording medium.
A contact angle with respect to water of the surface of the electrostatic charge image bearing member is 95 degrees or more, a surface roughness Rz is 2 μm or less, and a small diameter side particle size distribution of the number average particle diameter of the toner is 1.24 or less. The image forming apparatus.

<6>
A cleaning means for cleaning the surface of the electrostatic charge image carrier after the toner image is transferred to the transfer body;
<5> The image forming apparatus according to <5>, wherein the cleaning unit is a cleaning blade.

  As described above, according to the present invention, an image forming method capable of forming a high-quality and high-quality color image stably over a long period of time, and obtaining excellent transferability and cleaning properties, and the same are used. An image forming apparatus can be provided.

<Image forming method>
In the image forming method of the present invention, an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic charge image bearing member, and a toner image is formed by developing the electrostatic latent image with a developer containing toner. In an image forming method comprising at least a developing step, a transferring step for transferring the toner image onto a transfer member, and a fixing step for thermally fixing the toner image onto the surface of a recording medium, the surface of the electrostatic charge image carrier surface with respect to water The contact angle is 95 degrees or more and the surface roughness Rz is 2 μm or less, and the small diameter side particle size distribution of the toner (hereinafter sometimes abbreviated as “(small diameter side particle size distribution index) GSDps”) is 1. .24 or less.

  Therefore, when an image is formed using the image forming method of the present invention, a high-quality and high-quality color image can be stably formed over a long period of time even when a toner having a smaller diameter than that of the conventional one is used. Transferability and cleaning properties can be obtained.

Since the toner used in the present invention has a small-diameter side particle size distribution index GSDps of 1.24 or less, an electrostatic charge image carrier (hereinafter sometimes abbreviated as “photosensitive member”) after the toner image is transferred. The proportion of fine toner which tends to remain on the surface and has a relatively large adhesion is small.
For this reason, the transfer efficiency at the time of transferring a toner image to a transfer body becomes high. In addition, since the amount of fine toner remaining on the photoconductor after transfer becomes smaller, it is easy to fundamentally suppress poor cleaning and a decrease in reliability over time.

The small-diameter side particle size distribution index GSDps needs to be 1.24 or less, more preferably 1.22 or less, and even more preferably 1.20 or less. When the small diameter side particle size distribution index GSDps exceeds 1.24, the proportion of the fine toner contained in the toner is relatively increased, so that the amount of the fine toner remaining on the photoconductor after the transfer is increased. For this reason, even if a photoreceptor having a smooth surface and low surface energy as described later is used, it becomes impossible to fundamentally suppress poor cleaning and a decrease in reliability over time.
On the other hand, the lower limit value of the small diameter side particle size distribution index GSDps is not particularly limited, but is practically preferably 1.16 or more from the viewpoint of manufacturability of the toner having such a particle size distribution. The definition and measurement method of the small diameter side particle size distribution index GSDps will be described later.

  Further, since the photoreceptor used in the present invention has a surface contact angle with water of 95 degrees or more, the surface energy of the photoreceptor surface is low. For this reason, the photoconductor used in the present invention has a high releasability with respect to the fine toner, and the fine toner hardly remains on the photoconductor after the transfer. For this reason, depending on the conditions, the process itself for cleaning the surface of the photoreceptor can be omitted. In such a case, mechanical stress applied to the surface of the photoconductor by cleaning can be eliminated, so that the life of the photoconductor can be dramatically improved.

  On the other hand, even if fine toner remains on the photoreceptor after transfer, the surface of the photoreceptor to which the toner adheres despite the high adhesion of the fine toner to the solid surface. Due to the low surface energy, sticking hardly occurs. Further, since the fine toner remaining on the surface of the photoreceptor can be removed with a smaller force, the cleaning property can be improved when a cleaning method using a mechanical force is used.

The contact angle of water on the surface of the photoreceptor with respect to water needs to be 95 degrees or more, more preferably 100 degrees or more, and even more preferably 105 degrees or more. When the contact angle is less than 95 degrees, the releasability of the fine toner is deteriorated, the cleaning property is deteriorated, and the fine toner is easily fixed, so that the reliability with time is lowered.
The upper limit of the contact angle is not particularly limited and is preferably as large as possible, but because the physical properties of the low surface energy material itself used to form the surface layer of the photoreceptor and the choices of such materials are limited, Practically, it is preferably 140 degrees or less.
The contact angle was measured by dropping pure water on a sample obtained by cutting out the surface of the photoreceptor using a self-made contact angle measurement device in an environment of 23 ° C. and 55% RH. In addition, the average value when the measurement was repeated three times at different locations was determined as the contact angle of the photoreceptor surface with water.

Furthermore, since the surface roughness Rz of the surface of the photoreceptor used in the present invention is 2 μm or less, the smoothness of the surface of the photoreceptor is high. For this reason, it is possible to reduce the mechanical catching of the fine toner on the uneven surface on the surface of the photoconductor and the embedding in the concave portion, and the releasability of the fine toner due to the synergistic effect with the low surface energy of the photoconductor surface. As well as more effectively preventing sticking to the surface of the photoreceptor.
Further, when a cleaning blade is used as a cleaning means for cleaning the surface of the photosensitive member, a slight gap at the nip portion between the surface of the photosensitive member and the cleaning blade and unevenness of the blade nip pressure at the nip portion can be further reduced. For this reason, it is possible to prevent the fine toner remaining on the surface of the photosensitive member from slipping between the cleaning blade and the photosensitive member, and to maintain excellent cleaning properties for a long period of time.

The surface roughness Rz of the surface of the photoreceptor is required to be 2 μm or less, more preferably 1.5 μm or less, and further preferably 1.0 μm or less. When the surface roughness Rz exceeds 2 μm, the fine toner is likely to be caught on the concave and convex portions on the surface of the photosensitive member and buried in the concave portions, so that the fine toner is fixed.
Further, when a cleaning blade is used as the cleaning means, fine toner remaining on the surface of the photoreceptor can easily pass through the nip portion between the cleaning blade and the photoreceptor, and the cleaning performance may be deteriorated.

The surface roughness Rz (10-point average surface roughness) was measured using a stylus type surface roughness measuring machine (trade name: Surfcom 1400A, manufactured by Tokyo Seimitsu Co., Ltd.). The measurement conditions were based on JIS94, and the evaluation length Ln = 4 mm, the reference length L = 0.8 mm, and the cut-off value = 0.8 mm.
Further, a contact needle made of diamond and having a conical shape with a spherical tip curvature radius of 2 μm was used, and an average value obtained by repeating measurement three times at different locations was obtained as the surface roughness Rz of the photoreceptor surface.

  As described above, the image forming method of the present invention uses a toner having a small proportion of fine toner and forms an image using a photoreceptor having a smooth surface and low surface energy. Even when an image is formed using, excellent transferability and cleanability can be obtained over a long period of time. For this reason, the image forming method of the present invention can use a small-diameter toner that can easily form a high-quality and high-quality color image without any problems.

Of course, the image forming method of the present invention can use a toner having a particle size as used in the conventional image forming method, but it is suitable for a small diameter toner which is difficult to use in the conventional image forming method. It is particularly preferable to use a toner having a smaller diameter because of its high properties.
The particle diameter of such a small toner is preferably 5 μm or less in terms of volume average particle diameter, and more preferably 4.0 μm or less. However, if the volume average particle diameter is too small, it may be difficult to produce the toner itself, or the cleaning property may be deteriorated. Therefore, in practice, the volume average particle diameter may be 2.0 μm or more. preferable.

  Further, the shape factor SF1 of the toner used in the present invention is preferably 125 or less. When the shape factor SF1 exceeds 125, particularly when a small diameter toner is used, the thickness of the toner image transferred to the transfer body in the transfer stage becomes thinner than when the conventional toner is used. It may be impossible to form a uniform image.

However, the shape factor SF1 means a value defined by the following expression (1).
Formula (1) SF1 = ((absolute maximum length of toner diameter) ² / projection area of toner) × (π / 4) × 100
In the present invention, the absolute maximum length of the toner diameter represented by the formula (1) and the projected area of the toner are photographed with an optical microscope (Nikon, Microphoto-FXA) and a toner particle image magnified to 500 times magnification. The obtained image information was obtained by introducing the image information into, for example, an image analysis apparatus (Luzex III) manufactured by Nicole through an interface and performing image analysis.
The value of the shape factor SF1 was calculated as an average value based on data obtained by measuring 1000 toner particles sampled randomly.

  Further, the surface property index of the toner used in the present invention is preferably 2.0 or less. When the surface property index exceeds 2.0, the transferability may be deteriorated. In particular, for paper or a transfer body having a large surface roughness, transfer may be uneven or high transfer efficiency may be obtained. In some cases, the image quality may deteriorate.

The surface property index value means a value defined by the following formula (2).
Formula (2) (Surface index value) = (Measured specific surface area) / (Calculated specific surface area)
However, in the formula (2), the calculated specific surface area is represented by 6Σ (n × R ² ) / {ρ × Σ (n × R ³ }), where n is a Coulter counter. This represents the number of particles in the channel (number / channel), R represents the channel particle size (μm) in the Coulter counter, and ρ represents the toner density (g / μm ³ ). The number of divisions of the channel is 16. The size of the division is 0.1 interval on the log scale.

  Moreover, in Formula (2), the specific surface area actual value is measured based on the gas adsorption / desorption method, and is obtained by obtaining the Langmuir specific surface area. As a measuring device, Coulter SA3100 type (manufactured by Coulter, Inc.), Gemini 2360/2375 (manufactured by Shimadzu Corporation), or the like can be used.

  The volume average particle size distribution index GSDv of the toner used in the present invention is preferably 1.25 or less. When GSDv exceeds 1.25, the resolution is remarkably lowered, causing image defects such as toner scattering and fogging.

In the present invention, the volume average particle size (cumulative volume average particle size D ₅₀ ) and the average particle size distribution index are, for example, measuring devices such as Coulter Counter TAII (Beckman-Coulter), Multisizer II (Beckman-Coulter). in volume relative to the measured particle size distribution of the divided particle size ranges based on (channel), the number of each draw a cumulative distribution from the small diameter side, the cumulative 16% and comprising a volume particle diameter D _16v, number D _16P In addition, the particle size that becomes 50% cumulative is _defined as volume D _50v and several D _50P , and the particle size that becomes cumulative 84% is defined as volume D _84v and several D _84P . Using these, the volume average particle size distribution index (GSDv) is calculated as (D _84v / D _16V ) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D _84P / D _16P ) ^1/2 . The small diameter side particle size distribution index GSDps is represented by D _50p / D _16p .

  The image forming method of the present invention is not particularly limited as long as it includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step as described above. Other known steps may be included. For example, a cleaning step for cleaning the surface of the photoconductor after the toner image is transferred to the transfer body may be provided. In this case, for example, the surface of the photoconductor can be cleaned using a cleaning blade. The transfer body used in the transfer process may be a recording medium itself such as paper, or may be an intermediate transfer body such as a belt or a roll.

  The toner having a narrow particle size distribution on the small diameter side used in the present invention as described above includes an aggregation step of aggregating the particles in a dispersion in which particles containing at least resin particles are dispersed to obtain aggregated particles, and the aggregation It can be produced using a production method (so-called emulsion polymerization aggregation method) including a fusing step of fusing particles by heating. Since the emulsion polymerization aggregation method is excellent in controllability of the particle size, shape, and particle structure of the toner such as particle size and particle size distribution, it is suitable as a method for producing the toner used in the present invention, particularly a small diameter toner.

(toner)
Next, the structure, constituent materials, manufacturing method and the like of the toner used in the present invention will be described in detail. The constituent materials will be described on the assumption that the toner is basically produced by using the emulsion polymerization aggregation method. Of course, the same material is used when the toner is produced by using another toner production method. Can be used.

-Binder resin-
As a resin (binder resin) constituting the toner used in the present invention produced by using the emulsion polymerization aggregation method, an amorphous polyester resin, a non-crystalline polyester resin, Various things, such as crystalline polyester resin, can be used.

  Examples of vinyl binder resins include vinyl styrenes such as styrene and parachlorostyrene, vinyl naphthalene, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, etc. Esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-methyl chloroacrylate, methacryl Methylene aliphatic carboxylic acid esters such as methyl acid, ethyl methacrylate, butyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, for example vinyl such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether Monomers such as N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone and the like, monomers having an N-containing polar group, methacrylic acid, acrylic acid, cinnamic acid, Homopolymers and copolymers of vinyl monomers such as vinyl carboxylic acids such as carboxyethyl acrylate and / or various polyesters, and various waxes can also be used.

  In the case of vinyl monomers, emulsion polymerization can be carried out using an ionic surfactant or the like to produce a resin fine particle dispersion. In the case of other resins, the resin is oily and has a relatively high solubility in water. If it is soluble in a low solvent, dissolve the resin in those solvents, disperse in fine particles in water with a disperser such as a homogenizer together with an ionic surfactant or polymer electrolyte, and then heat or reduce the solvent. The resin fine particle dispersion can be obtained by evaporating.

As the crystalline resin, a crystalline polyester resin is preferable, and an aliphatic crystalline polyester resin having an appropriate melting point is more preferable. Hereinafter, a crystalline polyester resin will be described as an example.
Some crystalline aliphatic polyesters, such as polycaprolactone, progress through ring-opening polymerization, but many are synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. , “Acid-derived constituent component” refers to a constituent site that was an acid component before the synthesis of the polyester resin, and “alcohol-derived constituent component” refers to a constituent site that was the alcohol component before the synthesis of the polyester resin. Point to.

  When the polyester resin is not crystalline, that is, amorphous, it is impossible to maintain toner blocking resistance and image storage stability while ensuring good low-temperature fixability. Therefore, in the present invention, the “crystalline polyester resin” refers to a resin having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning calorimetry (DSC). In the case of a polymer obtained by copolymerizing another component with the crystalline polyester main chain, when the other component is 50% by weight or less, this copolymer is also called crystalline polyester.

-Acid-derived components-
The acid-derived constituent component is preferably an aliphatic dicarboxylic acid, and particularly preferably a linear carboxylic acid.
For example, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid Acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc., or lower alkyl esters thereof And acid anhydrides, but are not limited thereto.

As the acid-derived constituent component, in addition to the above-mentioned aliphatic dicarboxylic acid-derived constituent component, constituent components such as a dicarboxylic acid-derived constituent component having a double bond and a dicarboxylic acid-derived constituent component having a sulfonic acid group are included. Is preferred.
The component derived from a dicarboxylic acid having a double bond is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a double bond, in addition to a component derived from a dicarboxylic acid having a double bond. Components are also included. The dicarboxylic acid-derived constituent component having a sulfonic acid group is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a sulfonic acid group, in addition to a constituent component derived from a dicarboxylic acid having a sulfonic acid group. Components are also included.

The dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing since the entire resin can be crosslinked using the double bond. Examples of such dicarboxylic acids include, but are not limited to, fumaric acid, maleic acid, 3-hexenedioic acid, and 3-octenedioic acid. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, fumaric acid, maleic acid and the like are preferable in terms of cost.
The dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a coloring material such as a pigment.

  Further, when emulsifying or suspending the entire resin in water to produce toner mother particles into fine particles, if there are sulfonic acid groups, emulsification or suspension is possible without using a surfactant, as will be described later. . Examples of such a dicarboxylic acid having a sulfone group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, 5-sulfoisophthalic acid sodium salt is preferable in terms of cost.

Content of acid-derived components other than aliphatic dicarboxylic acid-derived components (dicarboxylic acid-derived components having double bonds and / or dicarboxylic acid-derived components having sulfonic acid groups) in the acid-derived components 1 to 20 mol% is preferable, and 2 to 10 mol% is more preferable.
When the content is less than 1 constituent mol%, pigment dispersion may not be good, the emulsified particle diameter may be large, and adjustment of the toner diameter by aggregation may be difficult. On the other hand, if it exceeds 20 component mol%, the crystallinity of the polyester resin is lowered, the melting point is lowered, the image storage stability is deteriorated, or the emulsion particle size is too small to dissolve in water, and no latex is produced. Sometimes.

  In the present invention, “constituent mol%” refers to the percentage when each constituent component (acid-derived constituent component, alcohol-derived constituent component) in the polyester resin is 1 unit (mol).

-Alcohol-derived components-
The alcohol component is preferably an aliphatic dicarboxylic acid, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol. 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-dodecanediol, 1,12-undecanediol, 1,13-tridecanediol, 1,14-tetradecanediol 1,18-octadecanediol, 1,20-eicosanediol, and the like, but are not limited thereto.

  When the alcohol-derived constituent component is an aliphatic diol-derived constituent component, the content of the aliphatic diol-derived constituent component is 80 constituent mol% or more, and other components are included as necessary. Furthermore, when the alcohol-derived constituent component is an aliphatic diol-derived constituent component, the content of the aliphatic diol-derived constituent component is preferably 90 constituent mol% or more.

When the content of the aliphatic diol-derived constituent component is less than 80 constituent mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability are deteriorated. End up.
Other components included as necessary include diol-derived components having double bonds and diol-derived components having sulfonic acid groups.
Examples of the diol having a double bond include 2-butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol, and the like.
Examples of the diol having a sulfonic acid group include 1,4-dihydroxy-2-sulfonic acid benzene sodium salt, 1,3-dihydroxymethyl-5-sulfonic acid benzene sodium salt, and 2-sulfo-1,4-butanediol sodium. Examples include salts.

  When adding an alcohol-derived component other than these linear aliphatic diol-derived components, that is, when adding a diol-derived component having a double bond and / or a diol-derived component having a sulfonic acid group, The content of the diol-derived constituent component having a double bond and / or the diol-derived constituent component having a sulfonic acid group in the alcohol-derived constituent component is preferably 1-20 constituent mol%, and more preferably 2-10 constituent mol%.

When the content of the alcohol-derived constituent component other than the aliphatic diol-derived constituent component is less than 1 constituent mol% with respect to the total alcohol-derived constituent component, the pigment dispersion is not good or the emulsion particle size is increased. In some cases, it is difficult to adjust the toner diameter by aggregation.
On the other hand, if it exceeds 20 component mol%, the crystallinity of the polyester resin is lowered, the melting point is lowered, the image storage stability is deteriorated, or the emulsion particle size is too small to dissolve in water, and no latex is produced. Sometimes.

  The melting point of the binder resin of the toner is preferably 50 to 120 ° C., more preferably 60 to 110 ° C. If the melting point is lower than 50 ° C., the storage stability of the toner and the storage stability of the toner image after fixing may become a problem. On the other hand, if the temperature is higher than 120 ° C., sufficient low-temperature fixing may not be obtained as compared with conventional toners.

  In the present invention, the melting point of the crystalline resin is measured using a differential scanning calorimeter (manufactured by Mac Science: DSC3110, thermal analysis system 001) (hereinafter abbreviated as “DSC”) from room temperature. It can be determined as the melting peak temperature of the input compensated differential scanning calorimetry shown in JIS K-7121 when the measurement is performed at a temperature rising rate of 10 ° C. per minute up to 150 ° C. The crystalline resin may show a plurality of melting peaks, but in the present invention, the maximum peak is regarded as the melting point.

  The method for producing the polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. For example, direct polycondensation, transesterification method, etc. Produced separately for different types. The molar ratio (acid component / alcohol component) when the acid component reacts with the alcohol component varies depending on the reaction conditions and the like, and cannot be generally stated, but is usually about 1/1.

The production of the polyester resin can be carried out at a polymerization temperature of 180 to 230 ° C., and the reaction system is reacted under reduced pressure as necessary to remove water and alcohol generated during condensation.
When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. If there is a monomer with poor compatibility in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed may be condensed in advance before polycondensation with the main component. .

  Catalysts that can be used in the production of the polyester resin include alkali metal compounds such as sodium and lithium, alkaline earth metal compounds such as magnesium and calcium, and metal compounds such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium. , Phosphorous acid compounds, phosphoric acid compounds, amine compounds, etc., specifically, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, stearic acid Zinc, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, trib Ruantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, zirconium naphthenate, zirconyl carbonate, zirconyl acetate, zirconyl stearate, zirconyl octylate, germanium oxide, triphenyl Examples of the compound include phosphite, tris (2,4-di-t-butylphenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, and triphenylamine.

-Colorant-
As the colorant of the toner used in the present invention, a known colorant can be used. For example, the following colorant can be used.
Examples of the black pigment include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, and magnetite.
Examples of yellow pigments include yellow lead, zinc yellow, yellow iron oxide, cadmium yellow, chrome yellow, Hansa yellow, Hansa yellow 10G, benzidine yellow G, benzidine yellow GR, selenium yellow, quinoline yellow, permanent yellow NCG, and the like. be able to.

  Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, benzidine orange G, indanthrene brilliant orange RK, and indanthrene brilliant orange GK.

  Red pigments include Bengala, Cadmium Red, Red Plum, Mercury Sulfide, Watch Young Red, Permanent Red 4R, Risor Red, Brilliantamine 3B, Brilliantamine 6B, Daypon Oil Red, Pyrazolone Red, Rhodamine B Lake, Lake Red C Naphthol red such as Rose Bengal, Eoxin Red, Alizarin Lake, Pigment Red 146, 147, 184, 185, 155, 238 and 269.

  Blue pigments include bitumen, cobalt blue, alkali blue rake, Victoria blue rake, fast sky blue, indanthrene blue BC, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxare. Rate.

Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake.
Examples of the green pigment include chromium oxide, chromium green, pigment green, malachite green lake, final yellow green G, and the like.
Examples of white pigments include zinc white, titanium oxide, antimony white, and zinc sulfide.

Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white.
Examples of the dye include various dyes such as basic, acidic, dispersed, and direct dyes, such as nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

  These colorants are used alone or in combination. In the case where a toner is prepared using an emulsion polymerization aggregation method described later, these colorants are used as a dispersion. For example, a dispersion of colorant particles can be prepared using a media-type disperser such as a rotary shearing homogenizer, a ball mill, a sand mill, or an attritor, a high-pressure opposed collision disperser, or the like. Further, these colorants can be dispersed in an aqueous system by a homogenizer using a polar surfactant.

The colorant used in the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP permeability, and dispersibility in the toner.
The colorant can be added in the range of 4 to 15% by weight with respect to the total weight of the toner constituent solids. When using a magnetic material as a black colorant, 12 to 240% by weight can be added unlike other colorants.
The blending amount of the colorant is a necessary amount for securing the color developability at the time of fixing. Moreover, OHP transparency and color developability can be ensured by setting the center diameter (median diameter) of the colorant particles in the toner to 100 to 330 nm. The center diameter of the colorant particles can be measured, for example, with a laser diffraction particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.).

-Release agent-
As the release agent for the toner used in the present invention, a known release agent can be used. Specific examples thereof include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene, and a softening point by heating. Fatty acid amides such as silicones, oleic acid amides, erucic acid amides, ricinoleic acid amides, stearic acid amides, and plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, etc. And mineral waxes such as beeswax, montan wax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, microcrystalline wax, Fischer-Tropsch wax, and modified products thereof. Can .
These waxes are hardly dissolved in a solvent such as toluene at room temperature or very little even if dissolved.

These waxes are dispersed in water together with ionic surfactants, polymer electrolytes such as polymer acids and polymer bases, heated above the melting point, and have a strong shearing ability and pressure discharge type dispersers. (Gorin homogenizer, manufactured by Gorin Co., Ltd.) can be dispersed in the form of fine particles to prepare a dispersion of particles of 1 μm or less.
Further, if necessary, a polymerizable ultraviolet stable monomer may be contained in order to improve the weather resistance of the image.

  Examples of polymerizable UV-stable monomers are 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6-tetrapiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6 pentamethylpiperidine, 4-cyano-4- (meth) Piperidine compounds such as acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine are effective. . These can be used alone or in combination of two or more.

It is desirable to add these release agents in the range of 5 to 25% by weight based on the total weight of the toner constituent solids, in order to ensure the peelability of the fixed image in the oilless fixing system.
The particle size of the obtained release agent particle dispersion was measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). In addition, when using a release agent, after the resin fine particles, colorant particles and release agent particles are aggregated, it is possible to add a resin fine particle dispersion to adhere the resin fine particles to the surface of the aggregated particles. It is desirable from the viewpoint of securing the property.

-Other (additives)-
For the toner used in the present invention, a known internal additive or external additive can be used as necessary.
For example, when used as a magnetic toner, magnetic powder may be included. Specifically, a material that is magnetized in a magnetic field is used, but a ferromagnetic powder such as iron, cobalt, or nickel, or a compound such as ferrite or magnetite is used.
When obtaining toner in the aqueous phase, it is necessary to pay attention to the aqueous phase migration of the magnetic material, and it is preferable to modify the surface of the magnetic material in advance, for example, to perform a hydrophobic treatment or the like.

  Also, magnetic materials such as ferrite, magnetite, reduced iron, cobalt, nickel, manganese and other metals, alloys, and compounds containing these metals are used as internal additives, and quaternary ammonium salt compounds, nigrosine-based as charge control agents. Various commonly used charge control agents such as dyes composed of complexes of compounds, aluminum, iron, chromium, and triphenylmethane pigments can be used. However, when the toner is prepared by using the emulsion polymerization aggregation method, a material that is difficult to dissolve in water is preferable from the viewpoint of controlling ionic strength that affects aggregation and temporary stability and reducing wastewater contamination.

In addition, various external additives can be added to the toner used in the present invention in the same manner as normal toners for the purpose of imparting fluidity and improving cleaning properties. For example, toner particles can be used by adding inorganic fine particles such as silica, alumina, titania and calcium carbonate and resin fine particles such as vinyl resin, polyester and silicone to the toner particle surface while being sheared in a dry state. .
When adhering to the toner surface in water, examples of inorganic fine particles include silica, alumina, titania, calcium carbonate, magnesium carbonate, and tricalcium phosphate. It can be used by dispersing with a surfactant, polymer acid or polymer base.

-Toner production method-
As described above, the toner used in the present invention is produced through at least the aggregation process and the fusion process, but the surface of the aggregated particles (core particles) formed through the aggregation process. It is more preferable to provide an adhesion step for forming aggregated particles having a core / shell structure in which polymer fine particles having a low surface energy are adhered to the surface.
Moreover, it is preferable that the dispersion liquid (raw material dispersion liquid) used by the aggregation process is adjusted using the emulsification process demonstrated below. Hereinafter, each step will be described in detail.

-Emulsification process-
The raw material dispersion is obtained by applying shear force to a solution in which emulsified particles of a binder resin (hereinafter abbreviated as “resin particles”) and an aqueous medium and a dispersion containing a colorant and a release agent as necessary are mixed. Formed by giving. Therefore, the binder resin needs to be dispersed in advance as resin particles in the raw material dispersion.

As an average particle diameter of the said resin particle, it is 1 micrometer or less normally, and it is preferable that it is 0.01-1 micrometer. When the average particle size exceeds 1 μm, the particle size distribution of the finally obtained toner may be broadened, or free particles may be generated, which may lead to a decrease in performance and reliability.
On the other hand, when the average particle size is within the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toners is improved, and the variation in performance and reliability is advantageous. The average particle diameter can be measured using, for example, a Coulter counter.

Examples of the dispersion medium in the dispersion include an aqueous medium and an organic solvent.
Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together. In the present invention, it is preferable to add and mix a surfactant in the aqueous medium. Although it does not specifically limit as surfactant, For example, anionic surfactants, such as sulfate ester type, sulfonate type, phosphate ester type, soap type; amine salt type, quaternary ammonium salt type, etc. Nonionic surfactants such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based, and the like.
Among these, anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The said surfactant may be used individually by 1 type, and may use 2 or more types together.

Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable.
Examples of the organic solvent include ethyl acetate and toluene, which are appropriately selected according to the binder resin.

  When the resin particle is a homopolymer or copolymer (vinyl resin) of a vinyl monomer such as the ester having a vinyl group, the vinyl nitrile, the vinyl ether, or the vinyl ketone. By conducting emulsion polymerization or seed polymerization of the vinyl monomer in an ionic surfactant, resin particles made of a vinyl monomer homopolymer or copolymer (vinyl resin) are made ionic. A dispersion obtained by dispersing in a surfactant is prepared.

  When the resin particle is a resin other than a homopolymer or a copolymer of the vinyl monomer, the resin can be dissolved in an oily solvent having a relatively low solubility in water. The resin is dissolved in the oily solvent, and this solution is dispersed in water together with an ionic surfactant and polymer electrolyte using a disperser such as a homogenizer, and then the oily solvent is evaporated by heating or decompression. Thus, a dispersion liquid in which resin particles made of resin other than vinyl resin are dispersed in an ionic surfactant is prepared.

  On the other hand, when the resin particles are a crystalline polyester and an amorphous polyester resin, some or all of the functional groups that contain a functional group that can be anionic by neutralization, have self-water dispersibility, and can be hydrophilic. Is neutralized with a base and can form a stable aqueous dispersion under the action of an aqueous medium. In the crystalline polyester and the amorphous polyester resin, the functional group that can become a hydrophilic group by neutralization is an acidic group such as a carboxyl group or a sulfone group. As the neutralizing agent, for example, sodium hydroxide, potassium hydroxide, water Examples thereof include inorganic bases such as lithium oxide, calcium hydroxide, sodium carbonate and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine.

  Further, when a polyester resin that does not disperse in water, that is, does not have self-water dispersibility, is used as a binder resin, the resin solution and / or an aqueous medium mixed with the resin solution, as described later, 1 μm easily when dispersed with a polymer electrolyte such as a surfactant, polymer acid, polymer base, etc., heated above the melting point, and treated with a homogenizer or pressure discharge type disperser capable of applying a strong shear force The following microparticles can be made. When this ionic surfactant or polymer electrolyte is used, the concentration in the aqueous medium is suitably about 0.5 to 5% by weight.

The center diameter (median diameter) of the fine particles in the resin fine particle dispersion thus obtained is preferably 1 μm or less, more preferably in the range of 50 to 400 nm, and in the range of 70 to 350 nm. More preferably it is.
In addition, the center diameter of resin fine particles can be measured, for example with a laser diffraction type particle size distribution measuring apparatus (LA-700, manufactured by Horiba, Ltd.).

-Aggregation process-
In the aggregation step, the raw material dispersion obtained by mixing at least a dispersion containing resin particles, a colorant, and a release agent is heated to form aggregated particles in which these fine particles are aggregated. When the resin particles are a crystalline resin such as crystalline polyester, the aggregated particles obtained by aggregating these fine particles are heated at a temperature near the melting point of the crystalline resin and at a temperature below the melting point. Form.

Aggregated particles are formed by adding a flocculant at room temperature under stirring with a rotary shearing homogenizer to make the pH of the raw material dispersion acidic.
As the aggregating agent used in the aggregating step, a surfactant having a polarity opposite to that of the surfactant used as the dispersing agent to be added to the raw material dispersion, that is, an inorganic metal salt or a metal complex having a valence of 2 or more is preferably used. Can do. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

In the case where the toner is produced without using the adhesion process described later, the resin particles used in the aggregation process are preferably made of a resin material having a small surface energy. In this case, the releasability of the toner with respect to the surface of the photoreceptor can be further improved.
As such a resin material for toner having a low surface energy, a resin material in which at least a part of hydrogen atoms are substituted with fluorine can be used.

-Adhesion process-
After passing through the aggregating step, an attaching step may be performed if necessary. In the attaching step, the coating layer is formed by attaching resin particles to the surface of the aggregated particles formed through the above-described aggregation step. Thereby, a toner having a so-called core / shell structure can be obtained.

  The coating layer can be formed by usually adding a dispersion containing amorphous polymer particles to the dispersion in which aggregated particles (core particles) are formed in the aggregation step. In addition, it is preferable that the resin particle utilized at an adhesion process consists of a resin material with small surface energy like the case mentioned above. In this case, the releasability of the toner with respect to the surface of the photoreceptor can be further improved.

  A surfactant can be used for emulsion polymerization of resin, dispersion of pigment, dispersion of resin fine particles, dispersion of a release agent, aggregation of particles, stabilization of aggregated particles, and the like. Specifically, sulfate surfactants, sulfonates, phosphates, soaps and other anionic surfactants, amine salts, quaternary ammonium salts and other cationic surfactants, polyethylene glycols, It is also effective to use a nonionic surfactant such as an alkylphenol ethylene oxide adduct system or a polyhydric alcohol system. As a dispersing means, a general method such as a ball mill, sand mill, or dyno mill having a rotary shear homogenizer or a media is used. Can be used

-Fusion process-
In the coalescence step performed after the aggregation step or after the aggregation step and the adhesion step, the pH of the suspension containing the aggregated particles formed through these steps is set in the range of 6.5 to 8.5. Thus, after the progress of aggregation is stopped, the aggregated particles are fused by heating. When a crystalline resin is used as the binder resin, the aggregated particles are fused by heating at a temperature equal to or higher than the melting point of the binder resin.

  A cross-linking reaction may be performed at the time of heating at the time of fusion or after the fusion is completed. In addition, a crosslinking reaction can be performed simultaneously with the fusion. When the crosslinking reaction is performed, for example, an unsaturated sulfonated crystalline polyester resin obtained by copolymerizing a double bond component as a binder resin is used, and a radical reaction is caused to the resin to introduce a crosslinked structure. be able to.

  Examples of the polymerization initiator include t-butyl peroxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t. -Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxyca) Bonyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, , 3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylper) Oxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxy) (Cyclohexyl) propane, di-t-butylperoxy α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydrotereph Tartrate, di-t-butylperoxyazelate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butylper Oxytrimethyl adipate, tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2'-azobis (2-methylpropionamidine dihydrochloride), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine], 4,4′-azobis (4-cyanovaleric acid) and the like.

These polymerization initiators can be used alone or in combination of two or more. The amount and type of the polymerization initiator are selected depending on the amount of unsaturated sites in the polymer and the type and amount of the coexisting colorant.
The polymerization initiator may be preliminarily mixed with the dispersion at the stage of preparing the raw material dispersion, or may be incorporated into the aggregated particles in the aggregation process. Further, it may be introduced after the fusion step or after the fusion step. In the case of introduction after the aggregation step, the adhesion step, the fusion step, or the fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to the dispersion. These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.

-Cleaning, drying process, etc.-
After completing the coalescence and coalescence process of the aggregated particles, the desired toner particles are obtained through an optional washing process, solid-liquid separation process, and drying process. Replacement cleaning is desirable. Moreover, although there is no restriction | limiting in particular in a solid-liquid separation process, From the point of productivity, suction filtration, pressure filtration, etc. are suitable. Further, the drying process is not particularly limited, but freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity. Further, various external additives as described above can be added to the toner particles after drying, if necessary.

-Particle size and particle size control-
The toner used in the present invention can be produced using the emulsion polymerization aggregation method as described above. The toner used in the present invention is required to have a small diameter side particle size distribution index GSDps of 1.24 or less. Such particle size control is performed, for example, by adding a flocculant while stirring with a homogenizer in the above-described aggregation step, adjusting the pH of the raw material dispersion to acidic, and further stirring, and then a reactor having a stirring blade The particle size distribution on the small diameter side can be narrowed by continuing to stir at room temperature for 1 hour. In addition, it is effective to obtain a narrow particle size distribution by heating the raw material dispersion to about 30 ° C. as necessary. In addition, when carrying out the adhering step, the particle size distribution can be narrowed by adding the resin particles for forming the coating layer and then carrying out the fusing step after stirring for about 1 hour. .

  Furthermore, the toner used in the present invention preferably has a volume average particle size of 5 μm or less. Such particle size control can be obtained by performing the growth of the aggregated particles at a temperature lower by 10 ° C. or more than the glass transition point of the resin particles in the aggregation process, and the smaller the aggregation temperature, the smaller the diameter. Toner particles can be obtained.

-Developer-
The toner obtained as described above is used as it is as a one-component developer or as a two-component developer. When used as a two-component developer, a toner and a carrier can be mixed and used.
There is no restriction | limiting in particular as a carrier which can be used for a two-component developer, A well-known carrier can be used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples thereof include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins and the like.

  Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. It is not limited.

Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. It is preferable.
The volume average particle size of the core material of the carrier is generally 10 to 500 μm, preferably 30 to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  The mixing ratio (weight ratio) of the toner of the present invention and the carrier in the two-component developer is in the range of toner: carrier = 1: 100 to 30: 100, and about 3: 100 to 20: 100. A range is more preferred.

<Image forming apparatus>
Next, an image forming apparatus using the image forming method of the present invention will be described. The image forming apparatus of the present invention can use an image forming apparatus using a normal electrophotographic method. Specifically, an electrostatic charge image carrier and an electrostatic latent image are formed on the surface of the electrostatic charge image carrier. An exposure unit; a developing unit that develops the electrostatic latent image with a developer containing toner to form a toner image; and a transfer unit that transfers the toner image on the surface of the electrostatic charge image carrier onto a transfer member; Preferably, the image forming apparatus includes at least a fixing unit that thermally fixes the toner image on a recording medium.
However, as the electrostatic charge image carrier, those having a surface contact angle with water of 95 ° or more and a surface roughness Rz of 2 μm or less are used, and the toner has a small diameter side particle size distribution of 1. What is 24 or less is used.

  Further, if necessary, other known members may be provided. For example, a cleaning unit for cleaning the surface of the photosensitive member after the toner image is transferred to the transfer member may be provided. In this case, it is preferable that the cleaning means is a cleaning blade.

(Photoconductor)
Hereinafter, the layer structure, the structure / function / material of each layer, the surface contact angle with respect to water, the surface roughness Rz, and the like will be described in detail with respect to the photoreceptor used in the present invention.
-Layer structure-
The photoreceptor used in the present invention has at least a photosensitive layer provided on a conductive substrate, and an undercoat layer, a surface protective layer, and the like can be provided as necessary. The photosensitive layer may be a single layer type containing a charge generation material, or may be a laminate type in which a charge generation layer and a charge transport layer are stacked.

The layer structure of the photoreceptor used in the present invention will be described below with reference to the drawings.
The photoconductor used in the present invention has no problem with any of the structures shown below, and is not limited to these structures. In addition, each schematic sectional drawing which shows the structure of the photoreceptor shown below expands and expresses a part of photoreceptor.

FIG. 1 is a schematic cross-sectional view showing the configuration of the photoreceptor of the first embodiment. In this photoreceptor, a charge generation layer 3a is provided on a conductive substrate 1, and a charge transport layer 3b is provided thereon.
FIG. 2 is a schematic cross-sectional view showing the configuration of the photoreceptor of the second embodiment. In this photoreceptor, an undercoat layer 2 is further provided between the conductive substrate 1 and the charge generation layer 3a in the layer configuration of the first embodiment.
FIG. 3 is a schematic cross-sectional view showing the configuration of the photoconductor of the third embodiment. In this photoreceptor, a surface protective layer 4 is further provided on the charge transport layer 3b with respect to the layer structure of the first embodiment.
FIG. 4 is a schematic cross-sectional view showing the configuration of the photoconductor of the fourth embodiment. In this photoreceptor, an undercoat layer 2 is further provided between the conductive substrate 1 and the charge generation layer 3a in the layer configuration of the third embodiment.

FIG. 5 is a schematic cross-sectional view showing the configuration of the photoconductor of the fifth embodiment. In this photoreceptor, a single-layer type photosensitive layer 3 c is provided on a conductive substrate 1.
FIG. 6 is a schematic cross-sectional view showing the configuration of the photoreceptor of the sixth embodiment. In this photoreceptor, an undercoat layer 2 is further provided between the conductive substrate 1 and the single-layer photosensitive layer 3c in the layer configuration of the fifth embodiment.
FIG. 7 is a schematic cross-sectional view showing the configuration of the photoconductor of the seventh embodiment. In this photoreceptor, a surface protective layer 4 is further provided on a single-layer type photosensitive layer 3c with respect to the layer structure of the sixth embodiment.

-Conductive substrate-
The conductive substrate can be opaque or substantially transparent, specifically, metals such as aluminum, nickel, chromium, stainless steel, and aluminum, titanium, nickel, chromium, stainless steel. Examples thereof include a plastic film provided with a film thickness of steel, gold, vanadium, tin oxide, indium oxide, ITO, etc., glass, or paper coated with or impregnated with a conductivity-imparting agent, plastic film and glass.

  These conductive substrates are used in an appropriate shape such as a drum shape, a sheet shape, or a plate shape, but are not limited thereto. Furthermore, the surface of the conductive substrate can be subjected to various treatments within a range that does not affect the image quality as necessary. For example, surface oxidation treatment, chemical treatment and coloring treatment, or irregular reflection treatment such as graining, etc. It can be performed. In particular, as a measure for preventing interference fringes, irregular reflection processing of a conductive substrate is one of effective means, and interference fringes can be suppressed by reducing the amount of regular reflection from the conductive substrate.

-Undercoat layer-
One or more undercoat layers may be provided between the conductive substrate and the photosensitive layer. The undercoat layer functions as an adhesive layer that prevents the injection of electric charge from the conductive substrate to the photosensitive layer when the photosensitive layer is charged, and also holds the photosensitive layer integrally bonded to the conductive substrate. Or, according to circumstances, it has a function of preventing reflection of light from the conductive substrate.

As the undercoat layer, known materials can be used. For example, polyethylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, Vinylidene chloride resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, water-soluble polyester resin, alcohol-soluble nylon resin, nitrocellulose, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, poly Resins such as acrylic acid and polyacrylamide and their copolymers, or curable organometallic compounds such as zirconium alkoxide compounds, titanium alkoxide compounds, and silane coupling agents can be used alone. It can be used in combination of two or more. A material that can transport only a charge having the same polarity as the charged polarity can also be used.
The film thickness of the undercoat layer is suitably from 0.01 to 10 μm, preferably from 0.05 to 5 μm. As a coating method, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method can be used.

-Charge generation layer-
As the charge generation material for the charge generation layer of the photoreceptor used in the present invention, known materials used for the charge generation layer of conventional J-shaped multilayer photoreceptors can be used. For example, amorphous selenium, selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and selenium alloys, zinc oxide, titanium oxide, a-Si, a-SiC and other inorganic photoconductive materials, phthalocyanine-based, squarylium Organic pigments and dyes such as, anthanthrone, perylene, azo, anthraquinone, pyrene, pyrylium salt and thiapyrylium salt can be used, but not limited to these, and two or more types can be mixed. May be used.

  Among the above-described charge generation materials of the present invention, phthalocyanine compounds have excellent photosensitivity in the range of 600 to 850 nm of the emission wavelength of LEDs and laser diodes currently used as light sources for digital image forming apparatuses. Therefore, it is particularly preferable as the charge generation material of the present invention. Specifically, metal-free phthalocyanine and metal phthalocyanine, and the central metal of the metal phthalocyanine includes Cu, Ni, Zn, Co, Fe, V, Si, Al, Sn, Ge, Ti, In, Ga, Mg, Pb, etc. These center metal oxides, hydroxides, halides, alkylates, alkoxylates, and the like can also be used.

Specifically, metal-free phthalocyanine, titanyl phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine, dichlorotin phthalocyanine, and the like can be given. Moreover, what has arbitrary substituents in these phthalocyanine rings can also be used. Furthermore, those in which any carbon atom in these phthalocyanine rings is substituted with a nitrogen atom are also effective.
As a form of these phthalocyanine compounds, an amorphous one or all crystalline polymorphs can be used. Among these phthalocyanine compounds, titanyl phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine and dichlorotin phthalocyanine have particularly excellent photosensitivity, and therefore are particularly preferably used as charge generation materials.

  Most of the phthalocyanine compounds described above have the property of p-type semiconductors whose main transport charge is holes, whereas dichlorotin phthalocyanine is an n-type semiconductor whose main transport charge is electrons. As a property. Therefore, an S-shaped photoreceptor containing dichlorotin phthalocyanine as a charge generation material and formed by sequentially laminating a charge generation layer and a charge transport layer on a conductive substrate is used when it is used with a negative charge. In addition, it is highly sensitive and suppresses injection of positive charges from the conductive substrate, and exhibits good electrophotographic characteristics with low dark decay and high chargeability.

  In addition, hexagonal selenium is excellent in charge generation efficiency and can be preferably used as a charge generation material. Since the beam diameter of the laser beam can be reduced as the transmission wavelength is shortened, shortening the wavelength of the exposure laser is being studied with the aim of further improving the image quality, but the photosensitive area of hexagonal selenium is about Since it is in a short wavelength region of 680 nm or less, hexagonal selenium is particularly preferably used as a charge generation material for a short wavelength laser in this range.

  The charge generation layer can be manufactured by vacuum deposition of the above charge generation material or by dispersing or dissolving the charge generation material in a binder resin. As the binder resin used for the charge generation layer, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal resin, polycarbonate resin, polyester resin, acrylic resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, vinyl chloride-acetic acid Examples include, but are not limited to, vinyl copolymers, silicone resins, phenol resins, poly-N-vinyl carbazole resins, and the like. These binder resins may be block copolymers, random copolymers or alternating copolymers, and can be used alone or in combination of two or more.

  The blending ratio (volume ratio) between the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10. More preferably, it is set in the range of 3: 1 to 1: 1. If the blending ratio of the charge generating material to the binder resin is larger than the above range, dark decay is increased and the mechanical properties are deteriorated. If it is less than the above range, obstacles such as a decrease in photosensitivity and an increase in residual potential are caused. Happens. The thickness of the charge generation layer is generally suitably in the range of 0.05 to 5 μm, preferably in the range of 0.1 to 2.0 μm. As the coating method, usual methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method can be used.

  When the regular reflectance at the exposure wavelength of the conductive substrate is large, the smaller transmittance at the exposure wavelength of the charge generation layer is advantageous for preventing interference fringes in order to reduce the regular reflected light intensity at the conductive substrate. It is. The transmittance at the exposure wavelength of the charge generation layer is preferably 50% or less, more preferably 20% or less, and even more preferably 10% or less. When the conductive substrate has a mirror surface and is not colored, it is preferably 3% or less.

  In order to prevent interference fringes, it is desirable to roughen the surface of the charge generation layer for the purpose of reducing specular reflection light at the interface between the charge generation layer and the charge transport layer. Although it is not always necessary to roughen the surface of the charge generation layer, the surface roughness (Ra2) of the charge generation layer in the case of roughening is preferably in the range of 0.03 to 0.5 μm. Preferably it is the range of 0.05-0.4 micrometer, More preferably, it is the range of 0.1-0.3 micrometer. If the surface roughness (Ra2) is smaller than the above range, the regular reflection light from the surface of the charge generation layer is not sufficiently suppressed, and interference fringes are generated. If it is larger than the above range, troubles such as black spots and white spots occur.

-Charge transport layer-
As the charge transport layer, known ones that are used as the charge transport layer in the conventional laminated photoreceptor can be used. For example, hole transporting low molecular compounds such as benzidine compounds, amine compounds, hydrazone compounds, stilbene compounds, carbazole compounds, or low electron transport properties such as fluorenone compounds, malononitrile compounds, diphenoxyquinone compounds, etc. A solid solution film in which molecular compounds are singly or mixed in two or more and dispersed uniformly in an insulating resin such as polycarbonate, polyarylate, polyester, polysulfone, polymethylmethacrylate, etc. A high molecular compound having the above can be used. In addition, an inorganic substance having a charge transporting ability such as selenium, amorphous silicon, and amorphous silicon carbide can also be used.

  Examples of the charge transporting polymer compound include a polymer compound having a group having a charge transporting ability such as polyvinyl carbazole in the side chain, and a group having a charge transporting ability as disclosed in JP-A-5-232727. A polymer compound having a main chain, polysilane, or the like can be used.

  In addition, a dispersion in which charge transporting fine particles are dispersed can be used in an appropriate binder resin which may contain a charge transport material. Examples of the material constituting the charge transporting fine particles include hexagonal selenium, cadmium selenide, other selenium compounds and selenium alloys, cadmium sulfide, zinc oxide, titanium oxide, a-Si, and a-SiC. Organic pigments such as phthalocyanine, squalium, anthanthrone, perylene, azo, anthraquinone, pyrene, pyrylium salt, thiapyrylium salt, benzidine compounds, amine compounds, hydrazone compounds, stilbene Electron transporting low molecular weight compounds such as hole transporting low molecular weight compounds such as fluorinated compounds, carbazole based compounds, or fluorenone based compounds, malonnitrile based compounds, diphenoxyquinone based compounds, etc. Absent. These charge transport materials can be used alone or in combination of two or more.

  The hexagonal selenium crystal does not substantially absorb light of 700 nm or more, which is the emission wavelength of a laser diode currently used as a light source in a digital image forming apparatus, and has excellent charge transport performance. Particularly preferred as charge transporting fine particles for a charge transport layer.

-Surface protective layer-
The structure described in the section of the charge transport layer is employed as it is for the surface protective layer, and is formed on the photosensitive layer formed on the surface of the conductive substrate by the method described above. The surface protective layer is a layer having high releasability, high water repellency, and high mechanical strength. The dry thickness of the surface protective layer is preferably about 1 to 10 μm. In order to increase the mechanical strength, a crosslinked structure can be formed, or an inorganic material having high hardness can be contained in the protective layer.

-Other additives-
In the photoreceptor used in the present invention, a surface protective layer or a layer near the surface of the charge transport layer constituting the surface of the photoreceptor when no surface protective layer is provided (hereinafter abbreviated as “outermost surface layer”). Other additives that may be included include antioxidants, light stabilizers, and heat stabilizers that are added to prevent degradation of the photoreceptor due to ozone, oxidizing gas, or light / heat generated in the image forming apparatus. Agents and the like.

  Specific examples of the antioxidant include phenolic antioxidants, hindered amine antioxidants, organic sulfur antioxidants, and organic phosphorus antioxidants. The organic sulfur-based and organic phosphorus-based antioxidants are referred to as secondary antioxidants, and a synergistic effect can be obtained by using them together with a primary antioxidant such as a phenol-based or amine-based antioxidant. The addition amount of the antioxidant is preferably 15% by weight or less, more preferably 10% by weight or less, based on the total solid content of the outermost surface layer.

  Specific examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives. The addition amount of the light stabilizer is preferably 5% by weight or less, more preferably 1% by weight or less, based on the total solid content of the outermost surface layer.

Further, for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, etc., one or more kinds of electron accepting substances can be contained in the outermost surface layer. The electron-accepting substance that can be used in the present invention is not particularly limited as long as it exhibits electron-accepting properties, but in particular, electron-withdrawing properties such as fluorenone-based, quinone-based, Cl, CN, NO _{2 and the} like. A benzene derivative having a substituent is preferred.

-Photoconductor surface (outermost surface layer and formation method thereof)-
As described above, the contact angle of water on the surface of the photoreceptor needs to be 95 ° or more.
In order to increase the contact angle of water on the surface of the photoreceptor, it is effective to contain a resin or a low molecular weight compound containing atoms such as fluorine or silicon in the outermost surface layer.

  Specifically, polymers of ethylene tetrafluoride, ethylene trifluoride, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, ethylene difluoride diethylene chloride, copolymers thereof, carbon fluoride, , Polymers with fluorine-based polymerizable monomers or non-fluorinated polymerizable monomers, block or graft polymers having fluorine-based segments synthesized from these copolymers, surfactants, macromonomers, etc. alone Or it can use together.

Examples of silicon-based compounds include monomethylsiloxane three-dimensional compounds, dimethylsiloxane-mnomethylsiloxane three-dimensional crosslinked products, polydimethylsiloxane, block polymers having polydimethylsiloxane segments, graft polymers, surfactants, macromonomers, terminal Modified polydimethylsiloxane can be used.
In the case of a solvent-insoluble three-dimensional cross-linked product such as fluorine-based fine particles and silicon-based fine particles, it can also be used in the form of fine particles. The fine particles are used together with the binder resin as a composition of the outermost layer.

  As a dispersion method, known ones such as a sand mill, a ball mill, a roll mill, a homogenizer, a nanomizer, a paint shaker, and an ultrasonic wave can be used. In addition, the above graft polymer, block polymer, surfactant and the like are used as a dispersion aid. be able to.

  These materials are organic together with other materials constituting the outermost surface layer constituting the surface of the photoreceptor (that is, the surface protective layer or the charge transport layer constituting the photoreceptor surface when the surface protective layer is not provided). It is dissolved and dispersed with a solvent to form a coating solution, which is applied to the surface of the photosensitive layer or the surface of the charge generation layer.

  Further, the surface roughness Rz of the photoreceptor surface needs to be 2 μm or less. For this reason, it is preferable to avoid the use of a particulate member that causes surface irregularities as a material constituting the outermost surface layer. Further, the surface roughness Rz of the photoreceptor surface can be reduced by preventing insoluble aggregates from being generated in the coating liquid used for forming the outermost surface layer. In order to improve the fineness of the outermost surface layer, it is important to reduce the particle size or increase the degree of dispersion when mixing inorganic fine particles. In order to remove semi-dissolved resin components and aggregated fine particles contained in the coating liquid used to form the outermost surface layer, the coating liquid may be purified in advance by a filter, centrifugation, or the like. Is important in order to reduce the thickness to 2 μm or less.

  The photoconductor used in the present invention is provided in a light lens type copying machine, a laser beam printer that emits near-infrared light or visible light, a digital copying machine, an LED printer, an image forming apparatus such as a laser facsimile, or an image forming apparatus. It can be suitably used for a process cartridge. The photoreceptor used in the present invention can be used in combination with a one-component or two-component regular developer or reversal developer. Furthermore, even when the photoreceptor used in the present invention is used in an image forming apparatus provided with a contact charger having a charging roller or a charging brush, a good image quality can be easily obtained with little current leakage.

As described above, the photoreceptor used in the present invention has a small contact angle with water on the surface (that is, low surface energy) and a small surface roughness Rz (high smoothness). The releasability of fine toner that tends to remain on the surface of the photoreceptor is high.
For this reason, it is not necessary to provide a cleaning means for cleaning the photoreceptor depending on conditions. In this case, it is possible to dramatically improve the life of the photoconductor, and the image forming apparatus of the present invention can be used as a so-called cleanerless type image forming apparatus having no cleaning function.

  On the other hand, even when a cleaning unit is provided, the releasability of fine toner that tends to remain on the surface of the photoconductor after the transfer process is high, so that the cleaning stress applied to the surface of the photoconductor is reduced when the photoconductor is cleaned. can do. For example, when a cleaning blade is used as the cleaning means, it is not necessary to increase the pressing force of the cleaning blade against the photoconductor more than necessary to ensure the cleaning performance. Therefore, it is possible to suppress the occurrence of scratches and wear on the surface of the photoreceptor due to the cleaning blade while maintaining good cleaning properties for a long period of time.

(Specific example of image forming apparatus)
Next, the image forming apparatus according to the present invention using the above-described toner having a small diameter side particle size distribution and a photoreceptor having a small surface roughness and a large contact angle with water will be described with reference to the drawings.
FIG. 8 is a schematic explanatory view showing the first embodiment of the image forming apparatus of the present invention.
The image forming apparatus includes a photoconductor 10, a charger (charging unit) 11 that charges the surface of the photoconductor 10, a power source 12 for applying a voltage to the charger 11, and a latent image on the surface of the photoconductor 10. An image input device (latent image forming means) 13 for forming the toner, a developing device (developing means) 14 for developing the electrostatic latent image on the surface of the photoreceptor 10 with toner to obtain a toner image, and transferring the formed toner image A transfer device (transfer means) 15 for transferring to the surface of the material 20, a cleaning device (cleaning means) 16 for removing residual toner and the like on the surface of the photoconductor 10, and a static eliminator 17 for removing the residual potential on the surface of the photoconductor 10. And a fixing device 18 that fixes the toner image transferred onto the surface of the transfer material 20 by heat and / or pressure.

  A corona discharge type (non-contact charging type) charger 11 is disposed on the photoconductor 10, and the charger 11 is operated by a voltage supplied from a power supply 12. In the present embodiment, the non-contact charging type is exemplified as the charging 11, but a configuration using a so-called contact charging type charger that is in contact with the photoreceptor 10 may be used. In the case of a configuration using a contact charging type charger, there is a case where the static eliminator 17 is not provided.

Among contact charging type chargers, it is preferable to use an injection charging type charger. There are various types of injection charging type chargers such as the invention described in JP-A-11-212333. For example, a liquid in which conductive powder such as carbon black is mixed with distilled water or the like is used as urethane. For example, a liquid injection charging type charger that performs contact charging by impregnating with a sponge such as the like and bringing it into contact with a photoreceptor. The merit of using the injection charging type charger is that the generation of NO _{x and the} like due to the discharge in the gap between the photoreceptor and the charger can be prevented, and the photoreceptor cleaning mechanism can be omitted.

FIG. 9 is a schematic explanatory view showing a second embodiment of the image forming apparatus of the present invention. 9, the same reference numerals as those in FIG. 8 indicate the same members and configurations as those in FIG. Further, a contact charging type charger such as a charging roller is adopted as the charger 11 ′, and the cleaning means is omitted. In FIG. 9, the image input device, the static eliminator, and the power source are not shown, but of course, the image forming apparatus includes these members.
In this image forming apparatus, unlike the image forming apparatus of the first embodiment, the photosensitive member 10, the charger 11, the image input device 13 and the developing device 14 are integrally supported by a cartridge 19.

  As described above, the photosensitive member and at least one unit selected from the group consisting of a charging unit, an image exposure unit, and a cleaning unit not included in the present embodiment are integrally supported and detachably attached to the image forming apparatus. The use of a certain process cartridge has an advantage that the user can avoid dirt on his hands and clothes due to toner.

  The image forming apparatus of the present invention has been described with reference to the two embodiments. However, the image forming apparatus of the present invention is not limited to the configuration shown in these embodiments, and the image of the present invention is not limited thereto. The configuration is not particularly limited as long as the forming method is used.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited by these Examples.

[Production of photoconductor]
<Photoreceptor A1>
(Preparation of conductive substrate)
For the conductive substrate, the surface of ED tube aluminum (84 mmφ) was roughened to a center line average roughness Ra = 0.18 μm by liquid honing using alumina spherical fine powder (volume average particle diameter D ₅₀ = 30 μm). What was processed was used.

(Formation of undercoat layer)
4 parts by weight of a polyvinyl butyral resin (ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) is dissolved in 170 parts by weight of n-butyl alcohol, and further 30 parts by weight of an organic zirconium compound (acetylacetone zirconium butyrate) and an organic silane compound (γ-amino). A mixture of 3 parts by weight of (propyltrimethoxysilane) was mixed and stirred to obtain a coating solution for forming an undercoat layer. The obtained undercoat layer-forming coating solution was applied to the surface of the conductive substrate by a dip coating method, and cured at 150 ° C. for 1 hour to form an undercoat layer having a thickness of 1.2 μm.

(Formation of charge generation layer)
Chlorgallium having diffraction peaks at positions of 7.4 °, 16.6 °, 25.5 °, and 28.3 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays. A mixture of 3 parts by weight of phthalocyanine, 2 parts by weight of vinyl chloride-vinyl acetate copolymer (VMCH, manufactured by Nihon Unicar) and 180 parts by weight of butyl acetate is dispersed for 4 hours by a sand mill, and applied for forming a charge generation layer. A liquid was obtained. The resulting charge generation layer forming coating solution was applied to the surface of the conductive substrate on which the undercoat layer was formed by a dip coating method, and this was dried to form a charge generation layer having a thickness of 0.2 μm. .

(Formation of charge transport layer)
a) Preparation of coating solution for charge transport layer N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (hole transport charge) Transport material) 4 parts by weight and 6 parts by weight of bisphenol Z-type polycarbonate (Iupilon Z400 manufactured by Mitsubishi Chemical Corporation), mixed with 600 parts by weight of tetrahydrofuran and 2 parts by weight of 2,6-di-tert-butyl-4-methylphenol In addition to the solvent, it was dissolved, and a polytetrafluoroethylene polymer particle dispersion (Fublon) manufactured by Daikin was mixed in an amount of 10% by weight and dispersed to obtain a coating solution for forming a charge transport layer.

b) Application / formation of charge transport layer coating solution The obtained charge transport layer forming coating solution is applied to the surface of the conductive substrate on which the undercoat layer and the charge generation layer are formed by a dip coating method. The film was dried at 120 ° C. for 40 minutes to form a charge transport layer having a thickness of 25 μm.
As described above, a photoreceptor A1 having a three-layer structure was produced.

(Evaluation of contact angle and surface roughness Rz)
Table 1 shows the contact angle of water on the surface of the obtained photoreceptor A1. Table 1 shows the surface roughness Rz before and after 100,000 image forming tests described later.

<Photoreceptor A2>
Photoreceptor A1 except that polytetrafluoroethylene polymer particles were not used in forming the charge transport layer and that a surface protective layer was formed on the charge transport layer surface as described below. In the same manner as described above, a photoconductor A2 having a four-layer structure was manufactured. Table 1 shows the results of evaluation in the same manner as for the photoreceptor A1.

-Formation of surface protective layer-
0.1 part by weight of a perfluoroalkyl acrylate-methyl methacrylate block copolymer (molecular weight 50000), 120 parts by weight of monochlorobenzene and 80 parts by weight of dichloromethane were mixed with a sand mill, and 3 parts by weight of triphenylamine was added and dissolved. A coating solution for forming the surface protective layer was prepared.
Next, this coating solution was spray-coated on the surface of the charge transport layer to form a coating film, followed by drying at 120 ° C. for 30 minutes to form a surface protective layer having a thickness of 3 μm.

<Photoreceptor A3>
A photoconductor A3 having a four-layer structure was prepared in the same manner as the photoconductor A2, except that the surface protective layer was formed as shown below when the photoconductor A3 was formed. Table 1 shows the results of evaluation in the same manner as for the photoreceptor A1.

-Formation of surface protective layer-
5.5 g of an aqueous dispersion of colloidal silica (solid content 40% by weight) is taken in a flask, and 20 g of an isopropyl alcohol dispersion of colloidal silica (solid content 30% by weight), 25.6 g of methyltriethoxysilane, 3, 6.0 g of 3,4,4,5,5,6,6,6-nonafluorohexyltrimethoxysilane and 3.0 g of acetic acid were added. After the addition, the mixed solution was heated to 65 to 70 ° C. and reacted for 2 hours. Thereafter, it is diluted with 21.7 g of isopropyl alcohol, 2.4 g of benzyltrimethylammonium acetate is added as a curing catalyst, and 0.16 g of a 10 wt% ethanol solution of polyether-modified dimethyl silicone is further added to form a surface protective layer. The coating solution was prepared.
Next, this coating solution is applied to the surface of the charge transport layer by a dip coating method to form a coating film, followed by drying and heat treatment at 110 ° C. for 4 hours, thereby forming a transparent and uniform surface protective layer having a thickness of 2 μm. Formed.

<Photoreceptor B1>
A photoconductor B1 having a three-layer structure was prepared in the same manner as the photoconductor A1, except that the polytetrafluoroethylene polymer particles were not used in forming the charge transport layer. Table 1 shows the results of evaluation in the same manner as for the photoreceptor A1.

[Production of toner and developer]
The toner was produced by the following process. First, each of the following resin fine particle dispersion, colorant particle dispersion, and release agent particle dispersion was prepared, and a polymer of a metal salt was added while mixing and stirring the mixture at a predetermined ratio. Neutralized to form aggregated particles. Next, an inorganic hydroxide was added to adjust the pH in the system from weakly acidic to neutral, and then the mixture was heated to a temperature equal to or higher than the glass transition point of the resin fine particles to be fused and united. After completion of the coalescence and coalescence reaction, a toner was obtained through sufficient washing, solid-liquid separation, and drying processes.

(Preparation of crystalline resin dispersion (1))
To a heat-dried three-necked flask, 92.5 mol% dimethyl sebacate and 7.5 mol% 5-t-butylisophthalic acid, ethylene glycol (2 mol times the acid component), and Ti (as a catalyst) OBu) ₄ (0.012% by weight with respect to the acid component), and then the pressure in the container is reduced by depressurization, and the atmosphere is inerted with nitrogen gas. Reflux was performed for 5 hours.
Then, excess ethylene glycol was removed by distillation under reduced pressure, the temperature was gradually raised to 220 ° C., and the mixture was stirred for 2 hours. When the mixture became viscous, the molecular weight was confirmed by GPC, and the weight average molecular weight became 12,000. The vacuum distillation was stopped and air-cooled to obtain crystalline polyester (1).

  Next, 80 g of this crystalline polyester (1) and 720 g of deionized water are placed in a stainless beaker, placed in a warm bath and heated to 95 ° C. When the crystalline polyester resin melted, the mixture was stirred at 8000 rpm using a homogenizer (manufactured by IKA: Ultra Tarrax T50). Subsequently, 20 g of an aqueous solution obtained by diluting 1.6 g of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) is added dropwise to carry out emulsification and dispersion, and a crystalline polyester resin dispersion having an average particle size of 0.15 μm (1) [Concentration of resin particles: 10% by weight] was prepared.

(Preparation of crystalline resin dispersion (2))
To a heat-dried three-necked flask, an acid component of 90.5 mol% of 1,10 dodecanedioic acid, 2 mol% of sodium dimethyl-5-sulfonate, 7.5 mol% of 5-t-butylisophthalic acid, 9 Nonanediol 100 mol% and Ti (OBu) ₄ (0.014% by weight with respect to the acid component) as a catalyst were added, and the air in the container was depressurized by depressurization and further inert with nitrogen gas. Under an atmosphere, reflux was performed at 180 ° C. for 6 hours with mechanical stirring.
Thereafter, excess ethylene glycol was removed by distillation under reduced pressure, the temperature was gradually raised to 220 ° C., and the mixture was stirred for 2 hours. When the mixture became viscous, the molecular weight was confirmed by GPC, and the weight average molecular weight was 11,000. The distillation under reduced pressure was stopped and air-cooled to obtain crystalline polyester (2).

  Next, 80 g of this crystalline polyester (2) and 720 g of deionized water are placed in a stainless beaker, placed in a warm bath, and heated to 95 ° C. When the crystalline polyester resin is melted, the mixture is stirred at 8000 rpm using a homogenizer (manufactured by IKA: Ultra Turrax T50). Subsequently, 20 g of an aqueous solution obtained by diluting 1.6 g of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) is added dropwise to carry out emulsification and dispersion, and a crystalline polyester resin dispersion having an average particle size of 0.15 μm. (2) [resin particle concentration: 10% by weight] was prepared.

(Preparation of amorphous resin fine particle dispersion (1))
-Styrene: 480 parts by weight-n-butyl acrylate: 120 parts by weight-Carboxyethyl acrylic acid: 18 parts by weight-Dodecanethiol: 12 parts by weight The above components are mixed and dissolved to prepare a solution. On the other hand, 12 parts by weight of an anionic surfactant (manufactured by Dow Chemical Co., Dowfax) is dissolved in 250 parts by weight of ion-exchanged water, and the above solution is added and dispersed and emulsified in a flask (monomer emulsion A ) Was adjusted.

Furthermore, 1 part by weight of an anionic surfactant (manufactured by Dow Chemical Co., Dowfax) is dissolved in 555 parts by weight of ion-exchanged water and charged into a polymerization flask.
The polymerization flask is sealed, a reflux tube is installed, and the polymerization flask is heated to 75 ° C. with a water bath while being slowly stirred while injecting nitrogen. 9 parts by weight of ammonium persulfate was dissolved in 43 parts by weight of ion-exchanged water and dropped into the polymerization flask via a metering pump over 20 minutes, and then the monomer emulsion A was added for 200 minutes through the metering pump. Add dropwise. Thereafter, the polymerization flask is kept at 75 ° C. for 3 hours while continuing the slow stirring to complete the polymerization.
As a result, an amorphous resin fine particle dispersion (1) having a center diameter of fine particles of 250 nm, a glass transition point of 55 ° C., a weight average molecular weight of 27000, and a solid content of 42% was obtained.

(Preparation of colorant particle dispersion (1))
-Yellow pigment (manufactured by Clariant Japan, PY74): 50 parts by weight-Anionic surfactant (Daiichi Kogyo Seiyaku, Neogen R): 5 parts by weight-Ion-exchanged water: 200 parts by weight The above ingredients are mixed and dissolved, The mixture was dispersed for 10 minutes with a homogenizer (manufactured by IKA, Ultra Tarrax) to obtain a yellow colorant particle dispersion (1) having a center diameter of 200 nm and a solid content of 21.5%.

(Preparation of colorant particle dispersion (2))
The colorant particle dispersion (1) was prepared in the same manner as the colorant particle dispersion (1) except that a cyan pigment (manufactured by Dainichi Seika Co., Ltd., copper phthalocyanine B15: 3) was used instead of the yellow pigment. Thus, a Cyan coloring agent particle dispersion (2) having a center diameter of 190 nm and a solid content of 21.5% was obtained.

(Preparation of colorant particle dispersion (3))
In the preparation of the colorant particle dispersion (1), except that a magenta pigment (manufactured by Dainichi Ink Chemical Co., PR122) was used instead of the yellow pigment, it was prepared in the same manner as the colorant particle dispersion (1). A colorant particle dispersion (3) having a center diameter of 160 nm and a solid content of 21.5% was obtained.

(Preparation of colorant particle dispersion (4))
The colorant particle dispersion (1) was prepared in the same manner as the colorant particle dispersion (1) except that a black pigment (Cabot, carbon black) was used instead of the yellow pigment, and the center diameter was 170 nm. A colorant particle dispersion (4) having a solid content of 21.5% was obtained.

(Preparation of release agent particle dispersion)
・ HNP09 (manufactured by Nippon Seiwa Co., Ltd., melting point 75 ° C.): 50 parts by weight • Anionic surfactant (Dow Chemical Co., Dow Fax): 5 parts by weight • Ion-exchanged water: 200 parts by weight Heat the above components to 110 ° C. Then, after sufficiently dispersing with a homogenizer (IKA, Ultra Tarrax T50), it is dispersed with a pressure discharge type homogenizer (Gorin homogenizer, Gorin) and separated with a center diameter of 120 nm and a solid content of 21.0%. A mold agent particle dispersion was obtained.

(Production of Toner A1 and Developer)
Amorphous resin fine particle dispersion (1): 130.8 parts by weight (54.94 parts by weight of resin)
Colorant particle dispersion (1): 39.5 parts by weight (8.5 parts by weight of pigment)
Release agent particle dispersion: 38.1 parts by weight (release agent 8 parts by weight)
-Polyaluminum chloride: 0.14 parts by weight The above components are thoroughly mixed and dispersed in a round stainless steel flask with a homogenizer (IKA, Ultra Turrax T50), and then the flask is stirred in a heating oil bath. After heating to 50 ° C. and holding at 50 ° C. for 60 minutes, 68 parts by weight of amorphous resin fine particle dispersion (1) (28.56 parts by weight of resin) was added and gently stirred. Thereafter, the temperature was raised to 51 ° C., maintained at the same temperature for 180 minutes, and it was confirmed with a Coulter counter that the particle size distribution became narrower.

Thereafter, the pH of the system was adjusted to 6.5 with a 0.5 mol / liter aqueous sodium hydroxide solution, and then heated to 95 ° C. while stirring was continued.
After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then solid-liquid separated by Nutsche suction filtration. And it re-dispersed in 3 liters of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This washing operation was repeated 5 times, followed by solid-liquid separation by Nutsche suction filtration, and then the final drying temperature was set to 40 ° C., followed by lyophilization for 10 hours to obtain toner particles (toner A1).

When the particle size of the toner particles was measured with a Coulter counter, the cumulative volume average particle size D ₅₀ was 4.6 μm, the small particle size distribution index GSDps was 1.23, and the surface property index was 1.5. Further, the shape factor SF1 of the toner particles obtained from the shape observation by Luzex was 120 spherical.

2 parts by weight of hydrophobic silica (manufactured by Cabot, TS720) was added to 50 parts by weight of the above toner particles, and mixed with a sample mill to obtain an externally added toner.
Then, using a ferrite carrier having an average particle diameter of 50 μm coated with 1% of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd.), the externally added toner is weighed so that the toner concentration becomes 5%. A developer was prepared by stirring and mixing for a minute.

(Production of toner A2 and developer)
The amorphous resin fine particle dispersion (1) is changed to the crystalline resin fine particle dispersion (1), and the colorant particle dispersion (1) is changed to the colorant particle dispersion (2). The toner particles (toner A2) were obtained in the same manner as in the production of the toner A1, except that the toner particles were maintained at 0.0.
The cumulative volume average particle size D ₅₀ of the toner particles is 4.5 μm, the small particle size distribution index GSDps is 1.19, and the surface property index is 1.30. Further, the shape factor SF1 was 120 and spherical.
Subsequently, an external additive was added to the toner A2 in the same manner as the toner A1, and mixed with a carrier to prepare a developer.

(Production of toner A3 and developer)
Toner A1 was used except that the amorphous resin fine particle dispersion (1) was changed to the crystalline resin fine particle dispersion (2) and the colorant particle dispersion (2) was changed to the colorant particle dispersion (3). In the same manner as in the production, toner particles (toner A3) were obtained.
The cumulative volume average particle diameter D ₅₀ of the toner particles is 4.2 μm, the small diameter side particle size distribution index GSDps is 1.24, the surface property index is 1.35, and the shape factor SF1 is slightly spherical with 128.
Subsequently, an external additive was added to the toner A3 in the same manner as the toner A1, and mixed with a carrier to prepare a developer.

(Production of toner A4 and developer)
Toner A2 (toner A4) was obtained in the same manner except that the aggregation temperature was 40 ° C. when toner A2 was produced. The cumulative volume average particle diameter D ₅₀ of the toner particles is 3.2 μm, the small diameter side particle size distribution index GSDps is 1.20, the surface property index is 1.6, and the shape factor SF1 is a spherical shape of 121.
Subsequently, an external additive was added to the toner A4 in the same manner as the toner A1, and mixed with a carrier to prepare a developer.

(Production of Toner B1 and Developer)
The toner particles (in the same manner as in the production of the toner A1, except that the aggregation temperature is 54 ° C. and the time to reach the temperature is reduced by half and the pH at 95 ° C. is maintained at 6.0. Toner B1) was obtained.
The cumulative volume average particle diameter D ₅₀ of the toner particles is 5.1 μm, the small diameter side particle size distribution index GSDps in the number average particle diameter is 1.25, the surface property index is 2.05, the shape factor SF1 is 135, and the potato shape is obtained. It was.
Subsequently, an external additive was added to the toner B1 in the same manner as the toner A1, and mixed with a carrier to prepare a developer.

(Production of toner B2 and developer)
Toner particles (toner B2) were obtained in the same manner as in the preparation of toner A1, except that the aggregation temperature was 42 ° C. and the time to reach the temperature was shortened to 1/3.
The cumulative volume average particle diameter D ₅₀ of the toner particles is 3.50 μm, the small diameter side particle size distribution index GSDps in the number average particle diameter is 1.26, the surface property index is 1.75, the shape factor SF1 is 122, and the toner particles are spherical. It was.
Subsequently, an external additive was added to the toner B2 in the same manner as the toner A1, and mixed with a carrier to prepare a developer.

<Evaluation>
For evaluation, a DC 1250 remodeling machine manufactured by Fuji Xerox (fixing machine was changed to a so-called oil-less fixing machine in which the fixing roll was changed to a PFA tube and the oil supply device was removed from the fixing machine) as an image forming apparatus. used. This apparatus is provided with a cleaning blade as a cleaning means.
For each test, the combination of the above-described photoreceptor and toner was changed (the combination of the photoreceptor and toner is shown in Table 1).
The recording medium used for the test is rough paper (4024 paper manufactured by Xerox Co., Ltd.) with low surface smoothness, which tends to cause uneven image density and image defects when small-diameter toner is used. did.
Under such conditions, 100,000 continuous image formation tests were performed, and the initial image quality after 100,000 sheets and the surface roughness Rz of the photoreceptor were evaluated. The results are shown in Table 1.

The evaluation methods and evaluation criteria for the evaluation items of the initial image quality and the image quality after 100,000 sheets shown in Table 1 are as follows.
<Initial image quality>
Images at the initial stage of the test were visually observed and evaluated according to the following criteria.
◎: Very good without blurring or loss of image ○: Good without blurring or loss of image △: Slight occurrence of blurring or loss of image is acceptable, but acceptable X: Image loss has occurred, image quality There is a problem with

<Image quality after 100,000 sheets>
The image after forming 100,000 sheets of images was visually observed and evaluated according to the following criteria.
A: Good image quality is completely maintained as with the initial image quality B: Good image quality is maintained although there is a slight change compared to the initial image quality B: Image defects are present compared to the initial image quality, It is an acceptable range.
×: Image defect is observed compared to the initial image quality, and there is a problem in image quality (eg, background stains and streaks due to poor cleaning)

It is a schematic sectional drawing which shows the structure of the photoconductor of 1st Embodiment. It is a schematic sectional drawing which shows the structure of the photoconductor of 2nd Embodiment. It is a schematic sectional drawing which shows the structure of the photoconductor of 3rd Embodiment. It is a schematic sectional drawing which shows the structure of the photoconductor of 4th Embodiment. It is a schematic sectional drawing which shows the structure of the photoreceptor of 5th Embodiment. It is a schematic sectional drawing which shows the structure of the photoreceptor of 6th Embodiment. It is a schematic sectional drawing which shows the structure of the photoconductor of 7th Embodiment. 1 is a schematic explanatory diagram illustrating a first embodiment of an image forming apparatus of the present invention. It is a schematic explanatory drawing which shows 2nd Embodiment of the image forming apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive base | substrate 2 Undercoat layer 3a Charge generation layer 3b Charge transport layer 3c Single layer type photosensitive layer 4 Surface protective layer 10 Photoreceptor 11, 11 'Charger (charging means)
12 Power supply 13 Image input device (latent image forming means)
14 Developer (Developing means)
15 Transfer device (transfer means)
16 Cleaning device (cleaning means)
17 Static eliminator 18 Fixing device 19 Cartridge 20 Transfer material

Claims (6)

An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic image carrier, a developing step of developing the electrostatic latent image with a developer containing toner to form a toner image, and the toner image In an image forming method comprising at least a transfer step of transferring onto a transfer body, and a fixing step of thermally fixing the toner image to a recording medium surface,
A contact angle with respect to water of the surface of the electrostatic charge image bearing member is 95 degrees or more, a surface roughness Rz is 2 μm or less, and a small diameter side particle size distribution of the number average particle diameter of the toner is 1.24 or less. Image forming method.   The toner is produced through at least a coagulation step of aggregating the particles to obtain aggregate particles in a dispersion in which particles containing at least resin particles are dispersed, and a fusing step of fusing the aggregated particles by heating. The image forming method according to claim 1, wherein the image forming method is manufactured.   The image forming method according to claim 1, wherein the toner has a volume average particle diameter of 5 μm or less.   The image forming method according to claim 1, wherein the developer includes the toner and a carrier. An electrostatic image carrier, an exposure unit that forms an electrostatic latent image on the surface of the electrostatic image carrier, a developing unit that develops the electrostatic latent image with a developer containing toner, and a toner image; In an image forming apparatus comprising at least a transfer unit that transfers the toner image on the surface of the electrostatic image carrier onto a transfer member, and a fixing unit that thermally fixes the toner image on a recording medium.
A contact angle with respect to water of the surface of the electrostatic charge image bearing member is 95 degrees or more, a surface roughness Rz is 2 μm or less, and a small diameter side particle size distribution of the number average particle diameter of the toner is 1.24 or less. Image forming apparatus. A cleaning means for cleaning the surface of the electrostatic charge image carrier after the toner image is transferred to the transfer body;
The image forming apparatus according to claim 5, wherein the cleaning unit is a cleaning blade.

Images