JP2012123209A - Image forming method, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method for preventing wear and filming of an image carrier, contamination of a charging member, and pass-through of toner by supplying only an image carrier protective component and a lubricant component from developer; and stably providing images having excellent quality for a long period, as well as a process cartridge, and an image forming apparatus.SOLUTION: An image forming method is provided that includes a developing step for developing an electrostatic latent image formed on an image carrier with developer. The developer contains a granulated material including an image carrier protective component including a fatty acid metal salt, and a lubricant component formed of at least any one of silica, alumina, acrylic particles, and boron nitride; and toner. Also provided are a process cartridge, and an image forming apparatus.

Description

  The present invention relates to an image forming method, a process cartridge, and an image forming apparatus.

Conventionally, in electrophotographic image formation, a latent image is formed by an electrostatic charge on an image carrier such as a photoconductive substance, and charged toner particles are attached to the electrostatic latent image to form a visible image. Form. The visible image formed by the toner particles is finally transferred to a transfer medium such as paper, and then fixed to the transfer medium by heat, pressure, solvent gas, etc., and becomes an output image.
These image forming methods use a so-called two-component development method in which toner particles and carrier particles are frictionally charged by stirring or mixing the toner particles for visualization, and carrier particles are used. In other words, the toner particles are roughly classified into so-called one-component development systems in which charge is imparted to toner particles. The one-component development method is classified into a magnetic one-component development method and a non-magnetic one-component development method depending on whether magnetic force is used for holding toner particles on the developing roller.

  Up to now, copiers that require high speed and image reproducibility, and multi-function machines based on these, have two components due to demands such as toner particle charging stability, start-up stability, and long-term image quality stability. On the other hand, a single component development method has been often used in small printers, facsimiles, and the like, which have great demands for space saving and cost reduction.

These electrophotographic image forming apparatuses are uniformly charged while rotating an image carrier (generally a photoconductor) generally in the form of a drum or a belt, regardless of the development method. A latent image pattern is formed on the image carrier by light or the like, and the toner image visualized by the developing device is further transferred onto a transfer medium.
The toner component that has not been transferred remains on the image carrier after the toner image is transferred to the transfer medium. When these residuals are conveyed as they are to the next charging step, the image carrier is often obstructed to be uniformly charged. Therefore, in general, the image carrier after the transfer step is an image. The toner component remaining on the carrier is removed by the cleaning member, and the surface of the image carrier is sufficiently cleaned, and then charging is performed.

  In recent years, in particular, the colorization of output images has progressed, and the demand for higher image quality and stabilization of image quality has become stronger than ever. To meet these demands, the average particle size of toner has been increased. Is smaller and the particle shape has become more spherical, with no angular portions. In order to remove the toner having a small particle diameter and a nearly spherical shape, a higher pressing pressure of the cleaning member against the image carrier is required as compared with the case of removing the conventional toner. The wear of the cleaning member and the like progresses remarkably.

As described above, various physical stresses or electrical stresses are present in each image forming process, and the image carrier, charging member, cleaning member, and the like deteriorate. It has become.
In order to solve this problem, many proposals have been made so far on various image carrier protective agent components, lubricant component supply and film formation methods for reducing deterioration of image carriers, charging members, cleaning members, etc. Has been made.

For example, in order to extend the life of the photoreceptor and the cleaning blade, it has been proposed to supply a solid protective agent (lubricant) mainly composed of zinc stearate to the photoreceptor surface to form a protective film on the photoreceptor surface. (See Patent Document 1). By this proposal, it is possible to suppress the wear of the surface of the photosensitive member and extend the life of the image carrier.
However, it has been found that the fatty acid metal salts such as zinc stearate lose its lubricity at an early stage due to the influence of discharge performed in the vicinity of the image carrier in the charging step. As a result, there is a problem that the lubricity between the cleaning blade and the image carrier is impaired, the toner slips through, and a defective image is generated.

For this problem, many proposals have been made to add inorganic fine particles such as boron nitride as external additives to the toner (see, for example, Patent Document 2). Since inorganic fine particles such as boron nitride do not lose their lubricity even when they are discharged in the charging step, defects such as toner slipping can be prevented.
However, in order for these external additives to exhibit a function suitable for the lubricity of fatty acid metal salts such as zinc stearate, it is necessary to supply a certain amount, and only inorganic fine particles are used as a developer. When added in a large amount, there is a problem that sticking (filming) to the surface of the image carrier occurs.

For this problem, several proposals have been made to supply a protective agent molded body such as zinc stearate by scraping with a brush and supplying a protective agent or lubricant from a developer (for example, And Patent Document 3). In these proposals, when the amount of the protective agent for obtaining a desired function is supplied only from the developer, the function of the developer is reduced. Therefore, for example, the protective agent molded in a block shape from other than the developer. It can be said that the amount of the protective agent added to the developer can be reduced by supplying the toner by a method of scraping with a brush roller or the like.
These proposals are excellent in that the effect of protecting the image carrier can be stably obtained even under various conditions, but depending on the material of the protective agent selected, development may be adversely affected. In particular, when a fatty acid metal salt is used as a protective agent added to a developer, the influence is remarkable, and there is a problem that the fluidity of the developer is lowered and the charge amount is lowered.

  In addition, as for the fatty acid metal salt including zinc stearate, a method of scraping the material molded into a block shape with a brush roller or the like and supplying it to the image carrier as in the above proposal, but in that case The number of members increases, the cost increases, and a large space is required around the image carrier, which is an obstacle to downsizing.

To solve these problems, for example, a fatty acid metal salt such as zinc stearate is added to the developer as a protective agent, and silica is further added as a lubricant in order to suppress a decrease in fluidity due thereto. It has been proposed (see Patent Document 4). In this proposal, the fatty acid metal salts such as stearic acid have high viscosity, so that the fluidity of the developer is lowered, but this can be prevented by adding inorganic fine particles such as silica. .
However, this proposal does not solve the problem that, when inorganic fine particles such as silica are added, sticking (filming) to the surface of the image carrier occurs as described above.

  Therefore, only the supply of the image carrier protective agent and lubricant from the developer is used without using a method such as scraping the protective agent or lubricant molded into a block shape with a brush roller and supplying it to the surface of the image carrier. An image forming method, process cartridge, and image cartridge capable of preventing wear and filming of the image carrier, contamination of the charging member, and toner slippage, and stably obtaining a good quality image over a long period of time. At present, the provision of an image forming apparatus is eagerly desired.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention can prevent image carrier wear and filming, charging member contamination, and toner slipping by only supplying the image carrier protective agent component and the lubricant component from the developer. An object of the present invention is to provide an image forming method, a process cartridge, and an image forming apparatus capable of stably obtaining an image of a high quality over a long period of time.

Means for solving the problems are as follows. That is,
<1> including a developing step of developing the electrostatic latent image formed on the image carrier with a developer,
The developer is
An image carrier protective agent component containing a fatty acid metal salt, and a granulated product containing a lubricant component consisting of at least one of silica, alumina, acrylic particles and boron nitride;
An image forming method comprising a toner.
<2> The image forming method according to <1>, wherein the fatty acid metal salt is zinc stearate.
<3> The image forming method according to any one of <1> to <2>, further including a protective layer forming step of pressing the image carrier protective agent component supplied to the surface of the image carrier to form a film. .
<4> The image forming method according to any one of <1> to <3>, wherein the image bearing member has at least one of alumina and silica dispersed in at least a layer formed on the outermost surface.
<5> The image forming method according to any one of <1> to <4>, wherein the image carrier includes a thermosetting resin at least in a layer formed on the outermost surface.
<6> The image forming method according to any one of <1> to <5>, wherein the image carrier is a photoconductor.
<7> The image forming method according to any one of <1> to <6>, further including a charging step of charging the image carrier with a charging unit disposed in contact with or close to the surface of the image carrier. .
<8> The image forming method according to <7>, wherein the charging unit includes a voltage applying unit that applies a voltage having an AC component.
<9> The image forming method according to any one of <1> to <3>, wherein the image carrier is an intermediate transfer medium.
<10> The image forming method according to any one of <1> to <9>, wherein an average particle diameter (D50) of the granulated product is 20 μm to 40 μm.
<11> The image forming method according to any one of <1> to <10>, wherein an average circularity (SR) represented by the following formula (1) of the toner is 0.93 to 1.00.
Circularity (SR) = perimeter of a circle having the same area as the particle projection area / perimeter of the particle projection image (1)
<12> Any one of <1> to <11>, wherein a ratio (D4 / D1) of the weight average particle diameter (D4) to the number average particle diameter (D1) of the toner is 1.00 to 1.40. The image forming method described.
<13> In a process cartridge that integrally includes at least an image carrier that carries an electrostatic latent image and a developing unit that develops the electrostatic latent image with a developer.
The developer is
An image carrier protective agent component containing a fatty acid metal salt, and a granulated product containing a lubricant component consisting of at least one of silica, alumina, acrylic particles and boron nitride;
A process cartridge containing toner.
<14> The process cartridge according to <13>, wherein the image bearing member has at least one of alumina and silica dispersed in at least a layer formed on the outermost surface.
<15> The process cartridge according to <13> to <14>, wherein the image carrier includes a thermosetting resin in at least a layer formed on the outermost surface.
<16> The process cartridge according to any one of <13> to <15>, further including a charging unit disposed in contact with or close to the surface of the image carrier.
<17> The process cartridge according to any one of <13> to <16>, wherein the granulated product has an average particle size (D50) of 20 μm to 40 μm.
<18> The process cartridge according to any one of <13> to <17>, further including a container containing a developer.
<19> The process cartridge according to any one of <13> to <18>, wherein the toner has an average circularity (SR) represented by the following formula (1) of 0.93 to 1.00.
Circularity (SR) = perimeter of a circle having the same area as the particle projection area / perimeter of the particle projection image (1)
<20> Any one of <13> to <19>, wherein a ratio (D4 / D1) of the weight average particle diameter (D4) to the number average particle diameter (D1) of the toner is 1.00 to 1.40. A process cartridge according to claim 1.
<21> An image forming apparatus comprising the process cartridge according to any one of <13> to <20>.

  According to the present invention, it is possible to solve the above-described problems and achieve the above-mentioned object, and it is possible to wear and fill the image carrier only by supplying the image carrier protective agent component and the lubricant component from the developer. An image forming method, a process cartridge, and an image forming apparatus that can prevent image formation, contamination of the charging member, and toner slipping, and can stably obtain a good quality image over a long period of time can be provided. .

FIG. 1 is a schematic configuration diagram showing an example of a process cartridge of the present invention.

(Image forming method)
The image forming method of the present invention includes at least a developing step of developing the electrostatic latent image formed on the image carrier with a developer, and further, if necessary, an image carrier protecting agent supplied to the surface of the image carrier. It includes other steps such as a protective layer forming step for forming a film by pressing the components, and a charging step for charging the image carrier by charging means arranged in contact with or close to the surface of the image carrier.

<Development process>
The developing step is a step of developing the electrostatic latent image formed on the image carrier with a developer. The developer used in the development step of the image forming method of the present invention includes an image carrier protecting agent component containing a fatty acid metal salt, and a lubricant component comprising at least one of silica, alumina, acrylic particles and boron nitride. It is essential to contain the granulated product and toner, and further contain other components as necessary.

-Granulated product-
It is essential that the image carrier protecting agent component and the lubricant component used in the present invention are mixed and granulated to form a granulated product.
Here, granulation refers to attaching and agglomerating fine powder, or compressing to form particles. In particular, in the present invention, an image carrier containing the fatty acid metal salt is mixed with a lubricant composed of at least one of silica, alumina, acrylic particles, and boron nitride, so that at least one particle of the lubricant is mixed. A grain of a size is to be molded.

There is no restriction | limiting in particular as the said granulation method, According to the objective, it can select suitably, For example, well-known methods, such as a dry type, a wet, and a melt-pulverization system, can be used. As an apparatus used for the granulation, for example, a roller compactor (RC-MINI, manufactured by Freund Corporation) can be used as a dry granulator. Of course, the granulator is not limited to this, and for example, a wet or melt-pulverized granulator may be used.
The granulation is performed by pulverizing or classifying the agglomerated particles, but the particle size can be controlled in the pulverization or classification process.

The particle size of the granulated product is not particularly limited as long as it is one or more particles of the powder used as the lubricant, and can be appropriately selected according to the purpose. D50) is preferably 10 μm to 100 μm, more preferably 20 μm to 40 μm. When the particle size is less than 10 μm, the development followability may deteriorate, and when it exceeds 100 μm, the photoreceptor protection property may deteriorate.
The particle size of the granulated product can be measured using, for example, a laser diffraction particle size distribution measuring device (SALD-2200, manufactured by Shimadzu Corporation).

  The mass mixing ratio (image carrier protecting agent / lubricant) when mixing the image carrier protecting agent and the lubricant is preferably 1/10 to 2/1, and preferably 1/5 to 1/1. More preferred. When the ratio is less than 1/10, the protective property of the image carrier may be lowered, and when it exceeds 2/1, the lubricity may be lowered.

  There is no restriction | limiting in particular as content in the said developer of the said granulated material, Although it can select suitably according to the objective, 0.05 mass%-3.0 mass% are preferable, 0.3 mass % To 1.0% by mass is more preferable. When the content is less than 0.05% by mass, the protective property of the photoreceptor or the cleaning property may not be exhibited. When the content exceeds 3.0% by mass, the development followability may be deteriorated.

  In addition, when the granulated product is added to the toner, the image carrier protecting agent component needs to be supplied to the photoreceptor even when an image having a low image area is formed. It needs to be free to some extent. Therefore, it is preferable that the granulated product and the toner are mixed with a weaker force than that when the external additive is added to the toner. For the mixing, for example, a tumbler mixer (T2F type, manufactured by Willy A Bachofen AG) can be used.

-Image carrier protective agent component-
The image carrier protective agent component contains a fatty acid metal salt, and further contains other components as necessary.
When the developer contains an image carrier protecting agent component, the image carrier can be prevented from being worn, and the cleaning property of the image carrier can be improved to form a good image.

  The fatty acid metal salt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, stearin Strontium acid, calcium stearate, cadmium stearate, magnesium stearate, zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, Cobalt palmitate, lead palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, Lumpur zinc, cadmium ricinoleate, and the like mixtures thereof. Among these, zinc stearate is preferable from the viewpoint of excellent protection of the image carrier. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  As content in the said developer of the said fatty-acid metal salt, 0.05 mass%-5.0 mass% are preferable, 0.05 mass%-1.0 mass% are more preferable, 0.1 mass%- 0.5% by mass is particularly preferred. When the content is less than 0.05% by mass, the image carrier may not be sufficiently protected. When the content exceeds 5.0% by mass, the fluidity of the developer may be significantly lowered.

--- Lubricant component--
The lubricant component is composed of at least one of silica, alumina, acrylic particles, and boron nitride.
When only the image carrier protective agent component is added to the developer, the fluidity of the developer is lowered, and development failure and transfer failure are likely to occur. By including the developer component together with the developer component, the fluidity of the developer can be increased, and development failure and transfer failure can be suppressed. Further, it is possible to improve the cleaning property of the image carrier and obtain a good image.
Note that a styrene-acrylic copolymer may be used as the acrylic particles.

The silica, alumina, acrylic particles and boron nitride are particulate powders, and the volume average particle diameter of these powders is preferably 0.01 μm to 10 μm, more preferably 0.02 μm to 5 μm, and 0 .2 μm to 5 μm is particularly preferable. If the average particle size of the powder is less than 0.01 μm, it may not be removed from the surface of the image carrier. If it exceeds 10 μm, the lubricity may not be exhibited.
The particle size of the powder can be measured using a Coulter Counter TA-II (Coulter).

  There is no restriction | limiting in particular as content in the said developer of the said lubricant, Although it can select suitably according to the objective, 0.05 mass%-5.0 mass% are preferable, and 0.25 mass% -1.0 mass% is more preferable. When the content is less than 0.05% by mass, lubricity may be insufficient. When the content exceeds 5.0% by mass, the lubricant may be excessively accumulated on the surface of the image carrier. .

-Toner-
Next, the toner used in the present invention will be described.
There is no restriction | limiting in particular as said toner, Although it can select suitably according to the objective, It is preferable that average circularity is 0.93-1.00. In this invention, what calculated | required the average from the value of circularity obtained from following formula (1) is defined as average circularity. This circularity is an index of the degree of unevenness of toner particles, and indicates 1.00 when the toner is a perfect sphere, and the average circularity becomes smaller as the surface shape becomes more complex.
Circularity (SR) = perimeter of a circle having the same area as the particle projection area / perimeter of the particle projection image (1)

  When the average circularity is in the range of 0.93 to 1.00, the surface of the toner particles is smooth, and the contact area between the toner particles and between the toner particles and the photosensitive member is small. Excellent. Further, since the toner particles have no corners, the developer agitation torque in the developing device is small, and the agitation drive is stabilized, so that no abnormal image is generated. In addition, since the proportion of toner particles that form squares is low in the toner that forms dots, the pressure is uniformly applied to the entire toner that forms the dots when pressed against the transfer medium in the transfer process. It is hard to cause a void. Further, since the toner particles are not angular, the abrasive power of the toner particles themselves is small, and the surface of the image carrier is not damaged or worn.

The average circularity can be measured using, for example, a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics Co., Ltd.
As a specific measuring method, 0.1 mL to 0.5 mL of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant in 100 mL to 150 mL of water from which impure solids have been previously removed in a container, Further, about 0.1 to 0.5 g of a measurement sample is added. The suspension in which the sample is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the concentration of the dispersion is set to 3,000 / μL to 10,000 / μL. Measure the particle size.

  There is no restriction | limiting in particular as a weight average particle diameter (D4) of the said toner, Although it can select suitably according to the objective, 3 micrometers-10 micrometers are preferable. If the weight average particle diameter (D4) is less than 3 μm, the transfer efficiency and blade cleaning properties are likely to decrease, and if it exceeds 10 μm, it is difficult to suppress scattering of characters or lines. On the other hand, when the weight average particle diameter (D4) is within the preferable range, toner particles having a sufficiently small particle diameter with respect to a minute latent image dot are provided, so that dot reproducibility is excellent.

The ratio (D4 / D1) between the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner is not particularly limited and may be appropriately selected depending on the intended purpose. 1.40 is preferred. When D4 / D1 is within the preferred range, selective development due to the toner particle size does not occur, and the image quality is excellent. In addition, since the toner particle size distribution is sharp, the triboelectric charge amount distribution is also sharp and the occurrence of fog is suppressed. In addition, when the toner particle diameters are uniform, the latent image dots are developed so as to be densely and orderly arranged, so that the dot reproducibility is excellent.
The closer the D4 / D1 value is to 1, the sharper the particle size distribution of the toner.

Next, a method for measuring the particle size distribution of toner particles will be described. Hereinafter, a method for measuring the particle size distribution of toner particles by the Coulter counter method will be described as an example.
First, 0.1 mL to 5 mL of a surfactant (preferably, alkylbenzene sulfonate) is added as a dispersant to 100 mL to 150 mL of the electrolytic aqueous solution. Here, the electrolytic solution is prepared by preparing an about 1% by mass NaCl aqueous solution using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 mg to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to dispersion treatment for about 1 minute to 3 minutes with an ultrasonic disperser, and the volume and number of toner particles or toner are measured with a measuring device using a 100 μm aperture as the aperture. Calculate volume distribution and number distribution. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained. As the measuring device, for example, Coulter Counter TA-II, Coulter Multisizer II (both manufactured by Coulter, Inc.) and the like can be used.
As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

  As the toner having a substantially spherical shape as described above, a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an aqueous medium in the presence of fine resin particles. A toner produced by crosslinking and / or elongation reaction is preferred. The toner produced by this reaction can reduce the hot offset by curing the toner surface, and can prevent the fixing device from becoming dirty and appearing on the image.

  Examples of the polyester prepolymer include a polyester prepolymer (A) having an isocyanate group, and examples of the compound that extends or crosslinks with the prepolymer include amines (B).

  There is no restriction | limiting in particular as the polyester prepolymer (A) which has the said isocyanate group, According to the objective, it can select suitably, For example, it is a polycondensate of a polyol (1) and a polycarboxylic acid (2), and Examples thereof include a product obtained by further reacting a polyester having an active hydrogen group with polyisocyanate (3). Examples of the active hydrogen group possessed by the polyester include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, an alcoholic hydroxyl group is preferable.

There is no restriction | limiting in particular as said polyol (1), According to the objective, it can select suitably, For example, diol (1-1) and trihydric or more polyol (1-2) are mentioned, (1- 1) The mixture of (1-1) and a small amount of (1-2) alone is preferable.
Examples of the diol (1-1) include alkylene glycol (eg, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); Alkylene ether glycol (eg, diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diol (eg, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.) ); Bisphenols (eg, bisphenol A, bisphenol F, bisphenol S, etc.); alkylene oxides of the above alicyclic diols (eg, ethylene oxide, propylene oxide) , Butylene oxide, etc.) adducts, alkylene oxide of the bisphenols (e.g., ethylene oxide, propylene oxide, and the like butylene oxide, etc.) adducts. Among these, alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols are preferable, and those using a combination of alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms are particularly preferable. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the trihydric or higher polyol (1-2) include 3 to 8 or higher polyhydric aliphatic alcohols (for example, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); 3 More than polyhydric phenols (for example, trisphenol PA, phenol novolac, cresol novolac, etc.); alkylene oxide adducts of the above trivalent polyphenols and the like. These may be used individually by 1 type and may use 2 or more types together.

There is no restriction | limiting in particular as said polycarboxylic acid (2), According to the objective, it can select suitably, For example, dicarboxylic acid (2-1) and trivalent or more polycarboxylic acid (2-2) are mentioned. (2-1) alone and a mixture of (2-1) and a small amount of (2-2) are preferred.
Examples of the dicarboxylic acid (2-1) include alkylene dicarboxylic acids (for example, succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (for example, maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (for example, Phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc.). Among these, alkenylene dicarboxylic acid having 4 to 20 carbon atoms and aromatic dicarboxylic acid having 8 to 20 carbon atoms are preferable. Examples of the trivalent or higher polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (for example, trimellitic acid and pyromellitic acid). These may be used individually by 1 type and may use 2 or more types together.
In addition, as said polycarboxylic acid (2), you may make it react with a polyol (1) using the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) of the above-mentioned thing.

  As the ratio of the polyol (1) and the polycarboxylic acid (2), the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH] is usually 2/1 to 1/1. 1.5 / 1 to 1/1 is preferable, and 1.3 / 1 to 1.02 / 1 is more preferable.

  The polyisocyanate (3) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include aliphatic polyisocyanates (for example, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethyl carbonate). Alicyclic polyisocyanates (eg, isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic diisocyanates (eg, tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (eg, α, α, α ′) , Α′-tetramethylxylylene diisocyanate); isocyanurates; those obtained by blocking the polyisocyanate with a phenol derivative, oxime, caprolactam or the like. These may be used individually by 1 type and may use 2 or more types together.

  As the ratio of the polyisocyanate (3) to the polycondensate of (1) and (2), the equivalent ratio [NCO] / [of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group is used. OH] is usually 5/1 to 1/1, preferably 4/1 to 1.2 / 1, and more preferably 2.5 / 1 to 1.5 / 1. When the [NCO] / [OH] is less than 1, the urea content in the modified polyester is lowered and the hot offset resistance is deteriorated. When it exceeds 5, the low-temperature fixability is deteriorated.

  The content of the polyisocyanate (3) component in the prepolymer (A) having an isocyanate group is usually 0.5% by mass to 40% by mass, preferably 1% by mass to 30% by mass. The mass% to 20 mass% is more preferable. When the content is less than 0.5% by mass, the hot offset resistance deteriorates and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. When the content exceeds 40% by mass, low-temperature fixability is obtained. Gets worse.

  The average number of isocyanate groups contained per molecule in the isocyanate group-containing prepolymer (A) is usually 1 or more, preferably 1.5 to 3, and preferably 1.8 to 2. 5 is more preferable. When the average number is less than 1, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.

There is no restriction | limiting in particular as said amine (B), According to the objective, it can select suitably, For example, diamine (B1), trivalent or more polyamine (B2), amino alcohol (B3), amino mercaptan ( B4), amino acid (B5), and those obtained by blocking the amino group of (B1) to (B5) (B6).
Examples of the diamine (B1) include aromatic diamines (eg, phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane); alicyclic diamines (eg, 4,4′-diamino-3,3 ′). Dimethyl dicyclohexyl methane, diamine cyclohexane, isophorone diamine, etc.); aliphatic diamines (eg, ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of the amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of the amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of (B6) obtained by blocking the amino group of (B1) to (B5) include amines and ketones of (B1) to (B5) (for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) And ketimine compounds and oxazoline compounds obtained from the above. Among these, a mixture of (B1) and (B1) and a small amount of (B2) is preferable. These may be used individually by 1 type and may use 2 or more types together.

  Furthermore, if necessary, the molecular weight of the synthesized polyester can be adjusted by using an elongation terminator. Examples of the elongation terminator include monoamines (for example, diethylamine, dibutylamine, butylamine, laurylamine, etc.), those having their functional groups blocked (for example, ketimine compounds), and the like.

  As the ratio of the amines (B), the equivalent ratio [NCO] / [NHx of the isocyanate group [NCO] in the prepolymer (A) having an isocyanate group and the amino group [NHx] in the amines (B) is used. ] Is usually 2/1 to 1/2, preferably 1.5 / 1 to 1 / 1.5, and more preferably 1.2 / 1 to 1 / 1.2. When the [NCO] / [NHx] is less than 1/2 or more than 2, the molecular weight of the urea-modified polyester (i) is lowered, and the hot offset resistance is deteriorated.

  In the toner used in the present invention, the polyester (i) modified with a urea bond may contain a urethane bond together with a urea bond. The molar ratio of urea bond content to urethane bond content (urea bond / urethane bond) is usually 100/0 to 10/90, preferably 80/20 to 20/80, and 60/40 to 30 / 70 is more preferable. When the molar ratio (urea bond / urethane bond) is less than 10/90, hot offset resistance deteriorates.

  By reacting these, a modified polyester, especially a urea-modified polyester (i), which is a binder resin component of the toner used in the present invention, can be produced. These urea-modified polyesters (i) are produced by a one-shot method, a prepolymer method, or the like.

  The weight average molecular weight of the urea-modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. When the weight average molecular weight is less than 10,000, the hot offset resistance deteriorates.

  The number average molecular weight of the urea-modified polyester (i) is not particularly limited when the unmodified polyester (ii) described later is used, and the number average molecular weight that can be easily obtained as the weight average molecular weight. If it is. The number average molecular weight of (i) alone is usually 20,000 or less, preferably 1,000 to 10,000, and more preferably 2,000 to 8,000. When the number average molecular weight exceeds 20,000, the low-temperature fixability and gloss when used in a full-color device are deteriorated.

  In the present invention, the polyester (i) modified with a urea bond may be used alone, but the above (i) is used in that the low-temperature fixability and the glossiness when used in a full-color device are improved. ) And unmodified polyester (ii) can also be included as a binder resin component. It is preferable to use (ii) in combination.

  The (ii) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, as with the polyester component (i), the weight of the polyol (1) and the polycarboxylic acid (2) A condensate etc. are mentioned, A preferable thing is the same as that of (i). The above (ii) is not limited to unmodified polyester, but may be modified with chemical bonds other than urea bonds, for example, modified with urethane bonds. The (i) and the (ii) are preferably at least partially compatible from the viewpoint of low-temperature fixability and hot offset resistance. Therefore, the polyester component (i) and the (ii) are preferably similar in composition.

  When (ii) is contained, the weight ratio (i / ii) between (i) and (ii) is usually 5/95 to 80/20, and 5/95 to 30/70. 5/95 to 25/75 is more preferable, and 7/93 to 20/80 is particularly preferable. When the weight ratio (i / ii) is less than 5/95, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight of (ii) is usually 1,000 to 30,000, preferably 1,500 to 10,000, and more preferably 2,000 to 8,000. When the peak molecular weight is less than 1,000, the heat-resistant storage stability deteriorates, and when it exceeds 30,000, the low-temperature fixability deteriorates.

The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If the hydroxyl value is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.
As an acid value of said (ii), it is 1-30 normally, and 5-20 are preferable. When (ii) has an acid value, it tends to be negatively charged.

  The glass transition point (Tg) of the binder resin obtained using the above materials is usually 50 ° C to 70 ° C, preferably 55 ° C to 65 ° C. When the glass transition point (Tg) is less than 50 ° C., blocking of the toner during high-temperature storage deteriorates, and when it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Due to the coexistence of the urea-modified polyester resin, the toner used in the present invention tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with known polyester-based toners.

As the storage elastic modulus of the binder resin, the temperature (TG ′) at which the measurement frequency is 20 Hz is 10,000 dyne / cm ² is usually 100 ° C. or higher, and preferably 110 ° C. to 200 ° C. When the TG ′ is less than 100 ° C., the hot offset resistance is deteriorated.

  As the viscosity of the binder resin, the temperature (Tη) at which the poise is 1,000 poise at a measurement frequency of 20 Hz is usually 180 ° C. or less, preferably 90 ° C. to 160 ° C. When the Tη exceeds 180 ° C., the low temperature fixability deteriorates.

Therefore, TG ′ is preferably higher than Tη from the viewpoint of achieving both low-temperature fixability and hot offset resistance. That is, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or higher, more preferably 10 ° C. or higher, and particularly preferably 20 ° C. or higher. The upper limit of (TG′−Tη) is not particularly limited.
Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg (Tη−Tg) is preferably 0 ° C. to 100 ° C., more preferably 10 ° C. to 90 ° C., and 20 ° C. to 80 ° C. Is particularly preferred.

The binder resin can be produced by the following method.
The polyol (1) and the polycarboxylic acid (2) are heated to 150 ° C. to 280 ° C. in the presence of a known esterification catalyst such as tetrabutoxy titanate, dibutyltin oxide, etc. To obtain a polyester having a hydroxyl group. Subsequently, this is made to react with polyisocyanate (3) at 40 to 140 degreeC, and the prepolymer (A) which has an isocyanate group is obtained. Further, the amine (B) is reacted with the above (A) at 0 ° C. to 140 ° C. to obtain a polyester modified with a urea bond. When reacting (3) and reacting (A) and (B), a solvent may be used as necessary. Usable solvents include aromatic solvents (eg, toluene, xylene, etc.); ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (eg, ethyl acetate, etc.); amides (eg, dimethyl) Inactive to isocyanate (3) such as formamide, dimethylacetamide and the like) and ethers (for example, tetrahydrofuran and the like). When polyester (ii) not modified with urea bond is used in combination, (ii) is produced by the same method as polyester having a hydroxyl group, and this is dissolved in the solution after completion of the reaction of (i) and mixed. To do.

Further, the toner used in the present invention can be produced generally by the following method, but is not limited thereto.
The toner particles may be formed by reacting the dispersion comprising (A) with (B) in an aqueous medium, or using urea-modified polyester (i) produced in advance.
As the aqueous medium, water alone may be used, but a solvent miscible with water may be used in combination. Examples of miscible solvents include alcohols (eg, methanol, isopropanol, ethylene glycol), dimethylformamide, tetrahydrofuran, cellosolves (eg, methyl cellosolve), lower ketones (eg, acetone, methyl ethyl ketone, etc.), and the like. It is done.

  As a method for stably forming the dispersion composed of the urea-modified polyester (i) to the prepolymer (A) in the aqueous medium, the composition of the toner raw material composed of the (i) to (A) is used. In addition, a method of dispersing by shearing force may be mentioned. Colorant, colorant masterbatch, release agent, charge control agent, unmodified polyester resin, etc. (A) and other toner compositions (hereinafter referred to as “toner raw material”) are dispersed in an aqueous medium. It may be mixed when forming the body, but it is preferable to mix the toner raw materials in advance and then add and disperse the mixture in the aqueous medium. Further, other toner raw materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium, and may be added after the particles are formed. Good. For example, after forming particles not containing a colorant, the colorant can be added by a known dyeing method.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied, but the particle size of the dispersion is set to 2 μm to 20 μm. From the viewpoint, a high-speed shearing type is preferable. When the high-speed shearing disperser is used, the rotation speed is not particularly limited and can be appropriately selected according to the purpose, but is usually 1,000 rpm to 30,000 rpm, and is 5,000 rpm. ~ 20,000 rpm is preferred. Moreover, there is no restriction | limiting in particular as dispersion time, Although it can select suitably according to the objective, In the case of a batch system, it is 0.1 minute-5 minutes normally. As temperature at the time of dispersion | distribution, it is 0 to 150 degreeC (under pressure) normally, and 40 to 98 degreeC is preferable. The higher the temperature, the lower the viscosity of the dispersion composed of the urea-modified polyester (i) to the prepolymer (A), and the easier the dispersion.

  The use amount of the aqueous medium with respect to 100 parts by mass of the toner composition containing the urea-modified polyester (i) to the prepolymer (A) is usually 50 parts by mass to 2,000 parts by mass, and 100 parts by mass to 1,000 parts by mass. Part by mass is preferred. When the amount used is less than 50 parts by mass, the dispersion state of the toner composition is poor, toner particles having a predetermined particle diameter cannot be obtained, and when it exceeds 2,000 parts by mass, it is not economical.

  Further, when dispersing the toner composition in the aqueous medium, a dispersant may be used as necessary. It is preferable to use the dispersant because the particle size distribution becomes sharp and the dispersion is stable.

  In the step of synthesizing the urea-modified polyester (i) from the prepolymer (A), the amine (B) may be added and reacted before the toner composition is dispersed in the aqueous medium. After dispersion, amines (B) may be added to cause a reaction from the particle interface. In this case, urea-modified polyester is preferentially generated on the surface of the toner to be produced, and a concentration gradient can be provided inside the particles.

  The dispersant for emulsifying and dispersing the oily phase in which the toner composition is dispersed in an aqueous medium is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include alkylbenzene sulfonate and α-olefin. Anionic surfactants such as sulfonates and phosphates, alkylamine salts, aminoalcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt type cationic surfactants such as imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts Salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, quaternary ammonium salt type cationic surfactants such as benzethonium chloride, fatty acid amide derivatives, nonionic surfactants such as polyhydric alcohol derivatives, Alanine, dodecyl di (aminoethyl) ) Glycine, di (octyl aminoethyl) glycine, N- alkyl -N, such amphoteric surface active agents such as tine base N- dimethyl ammonium. These may be used alone or in combination of two or more.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Suitable anionic surfactants having a fluoroalkyl group include, for example, fluoroalkylcarboxylic acids having 2 to 10 carbon atoms and their metal salts, disodium perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl ( C6-C11) oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11- C20) Carboxylic acid and metal salts thereof, perfluoroalkylcarboxylic acid (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acid and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl -N- (2hydroxy Ethyl) perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphoric acid Examples include esters. These may be used alone or in combination of two or more.

  The anionic surfactant having a fluoroalkyl group may be appropriately synthesized or a commercially available product may be used. Examples of the commercially available products include Surflon S-111, S-112, and S-113. (Above, manufactured by Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (above, manufactured by Sumitomo 3M Co., Ltd.), Unidyne DS-101, DS-102, (Daikin Industries, Ltd.) ), Megafuck F-ll0, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink Co., Ltd.), Xtop EF-102, EF-103, EF-104, EF-105, EF-112, EF-123A, EF-123B, EF-306A, EF-501, EF-201, EF-204 (above, Tochem Product Co., Ltd.) Ltd.), and the like FTERGENT F-100, F-150 (Co., Ltd. Neos).

  Examples of the cationic surfactant having a fluoroalkyl group include aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, and aliphatics such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. Examples include quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like. The cationic surfactant having a fluoroalkyl group may be synthesized as appropriate, and a commercially available product may be used. Examples of the commercially available product include Surflon S-121 (manufactured by Asahi Glass Co., Ltd.), Fluorard FC. -135 (manufactured by Sumitomo 3M Co., Ltd.), Unidyne DS-202 (manufactured by Daikin Industries Co., Ltd.), MegaFuck F-150, F-824 (manufactured by Dainippon Ink Co., Ltd.), Xtop EF-132 (Co., Ltd.) Tochem Products, Inc.), and Fantient F-300 (manufactured by Neos Co., Ltd.).

  As the dispersant, for example, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like can be used as an inorganic compound dispersant that is hardly soluble in water.

  Further, the dispersed droplets may be stabilized by using a polymer protective colloid. Examples of the polymeric protective colloid include acids such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, and maleic anhydride, or hydroxyl groups. (Meth) acrylic monomers containing, for example, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, Γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerin Monomethacrylic acid ester, N-methylol acrylamide, N-methylol methacrylamide, etc.); vinyl alcohol, ethers with vinyl alcohol (eg, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc.), vinyl alcohol and Esters with a compound containing a carboxyl group (for example, pinyl acetate, pinyl propionate, vinyl butyrate, etc.); acrylamide, methacrylamide, diacetone acrylamide and their methylol compounds; acid chlorides such as acrylic acid chloride and methacrylic acid chloride Homopolymers or copolymers such as those having a nitrogen atom or its heterocyclic ring such as pinylviridine, vinylpyrrolidone, vinylimidazole, ethyleneimine; polyoxyethylene, polyoxy Lopylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Examples include polyoxyethylenes such as ethylene nonylphenyl ester; and celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. These may be used individually by 1 type and may use 2 or more types together.

  In addition, when an acid such as calcium phosphate salt or an alkali-soluble one is used as a dispersion stabilizer, the calcium phosphate salt is dissolved with an acid such as hydrochloric acid and then washed with water, or by enzymatic decomposition, Remove calcium phosphate from fine particles.

  When the dispersant is used, the dispersant can remain on the surface of the toner particles. However, it is preferable from the charged surface of the toner that the dispersant is washed and removed after at least one of elongation and crosslinking.

In order to lower the viscosity of the toner composition, a solvent capable of further dissolving the urea-modified polyester (i) to the prepolymer (A) can be used. Use of the solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile in that it can be easily removed.
The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, Examples include trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, and methyl isobutyl ketone. These may be used individually by 1 type and may use 2 or more types together. Among these, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable, and aromatic solvents such as toluene and xylene are particularly preferable.

As a usage-amount with respect to 100 mass parts of prepolymers (A) of the said solvent, it is 0 mass parts-300 mass parts normally, 0 mass parts-100 mass parts are preferable, and 25 mass parts-70 mass parts are more preferable.
In addition, when the said solvent is used, it heats under a normal pressure or pressure reduction after reaction of at least any one of expansion | extension and bridge | crosslinking, and removes a solvent.

  The reaction time of at least one of the extension and the crosslinking cannot be generally described due to the reactivity due to the combination of the isocyanate group of the prepolymer (A) and the amines (B), but usually 10 minutes to 40 hours. 2 hours to 24 hours are preferable. As said reaction temperature, it is 0 to 150 degreeC normally, and 40 to 98 degreeC is preferable. Moreover, a well-known catalyst can be used for the said reaction as needed, and a dibutyltin laurate, a dioctyltin laurate etc. are mentioned as said catalyst, for example.

  In order to remove the organic solvent from the obtained emulsified dispersion, a method of gradually raising the temperature of the entire system and completely evaporating and removing the organic solvent in the droplets may be used. A method may be used in which the water-insoluble organic solvent in the droplets is completely removed by spraying in to form toner fine particles, and the aqueous dispersant is removed by evaporation. As a dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, in particular, various air currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient quality can be obtained in a short time using a spray dryer, belt dryer or rotary kiln.

When the particle size distribution at the time of emulsification dispersion is wide, and washing and drying processes are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classifying it into a desired particle size distribution.
The classification operation is performed by removing fine particles or coarse particles in a liquid by a cyclone, a decanter, centrifugation, or the like. The classification may be performed on a powder obtained after drying as a powder, but is preferably performed in a liquid from the viewpoint of efficiency. Unnecessary fine particles or coarse particles obtained by the classification can be returned to the kneading step and used to form particles. At that time, the fine particles or coarse particles may be in a wet state.

  When the dispersant is used, it is preferable to remove the dispersant simultaneously with the classification operation described above.

  The resulting dried toner powder is mixed with dissimilar particles such as release agent fine particles, charge control fine particles, fluidizing agent fine particles, and colorant fine particles, or mechanical impact force is applied to the mixed powder. Thus, the foreign particles can be immobilized and fused on the toner surface, and the foreign particles can be prevented from being detached from the surface of the composite particles.

  As a method of applying the mixing and mechanical impact force, a method of applying an impact force to the mixture with a blade rotating at high speed, a mixture is injected into a high-speed air stream, and the mixture is accelerated to appropriately collide the particles with each other and the composite particles. There is a method of making it collide with a board. As an apparatus used for this, for example, an ong mill (manufactured by Hosokawa Micron Co., Ltd.), an I-type mill (manufactured by Nippon Pneumatic Industrial Co., Ltd.), and a pulverization air pressure lowered, a hybridization system (Co., Ltd.) Nara Machinery Co., Ltd.), Kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), and automatic mortar.

  The colorant used in the toner is not particularly limited, and pigments and dyes that have been conventionally used as toner colorants can be used, such as carbon black, lamp black, iron black, ultramarine, nigrosine dye, Examples include aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6C lake, calco oil blue, chrome yellow, quinacridone red, benzidine yellow, and rose bengal. These may be used individually by 1 type and may use 2 or more types together.

The toner further has magnetic properties such as iron oxides such as ferrite, magnetite, and maghemite, metals such as iron, cobalt, and nickel, and alloys of these with other metals in order to give the toner particles magnetic properties as necessary. Ingredients may be included in the toner particles. These may be used individually by 1 type and may use 2 or more types together.
These components can also be used or used together as a colorant component.

  The number average particle diameter of the colorant in the toner used in the present invention is preferably 0.5 μm or less, more preferably 0.4 μm or less, and particularly preferably 0.3 μm or less. When the number average particle diameter exceeds 0.5 μm, the dispersibility of the pigment does not reach a sufficient level, and preferable transparency may not be obtained.

In addition, the colorant having a fine particle diameter having a number average particle diameter of less than 0.1 μm is sufficiently smaller than a half wavelength of visible light, and therefore, it is considered that the light reflection and absorption characteristics are not adversely affected. Therefore, such a colorant contributes to good color reproducibility and transparency of an OHP sheet having a fixed image.
On the other hand, if there are many colorants having a particle size of more than 0.5 μm, the transmission of incident light is hindered or scattered, resulting in the brightness of the projected image on the OHP sheet. And the color may be reduced. Further, the colorant is detached from the toner particle surface, and various problems such as fogging, drum contamination, and poor cleaning are likely to occur. In particular, the ratio of the colorant having a particle diameter exceeding 0.7 μm is preferably 10% by number or less of the total colorant, and more preferably 5% by number or less.

The colorant is preliminarily in a state where the binder resin and the colorant are sufficiently adhered by adding a wetting liquid in advance together with a part or all of the binder resin and then kneading. In the toner production process, the colorant is dispersed more effectively in the toner particles, the dispersed particle diameter of the colorant is reduced, and better transparency can be obtained.
The binder resin used for kneading in advance is not particularly limited, and resins exemplified as the binder resin for toner can be used, but are not limited thereto.

  As a method for kneading the mixture of the binder resin and the colorant in advance with the wetting liquid, for example, the binder resin, the colorant and the wetting liquid are mixed in a blender such as a Henschel mixer, and then the resulting mixture is mixed. It is carried out by kneading at a temperature lower than the melting temperature of the binder resin by a kneader such as a two-roll or three-roll. According to this manufacturing method, not only the particle diameter of the colorant particles contained in the obtained toner is reduced, but also the uniformity of the dispersion state of the particles is increased, so that the color reproducibility of the projected image by OHP is further improved. Get better.

  The wetting liquid is not particularly limited, and a general one can be used in consideration of solubility of the binder resin and paintability with the colorant. Particularly, acetone, toluene, butanone, etc. An organic solvent and water are preferable from the viewpoint of dispersibility of the colorant. Among these, water is even more preferable from the viewpoint of environmental considerations and maintaining the dispersion stability of the colorant in the subsequent toner production process.

The toner used in the present invention may contain a release agent typified by wax in addition to the binder resin and the colorant.
The release agent is not particularly limited, and known ones can be used. For example, polyolefin wax (for example, polyethylene wax, polypropylene wax, etc.); long chain hydrocarbon (for example, paraffin wax, sasol) Wax etc.); Carbonyl group containing wax etc. are mentioned. Among these, a carbonyl group-containing wax is preferable. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the carbonyl group-containing wax include polyalkanoic acid esters (for example, carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehe. Polyalkanol esters (eg, tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amides (eg, ethylenediamine dibehenyl amide); polyalkylamides (For example, trimellitic acid tristearyl amide); dialkyl ketone (for example, distearyl ketone) and the like. Among these, polyalkanoic acid ester is preferable. These may be used individually by 1 type and may use 2 or more types together.

  As melting | fusing point of these mold release agents, it is 40 to 160 degreeC normally, 50 to 120 degreeC is preferable and 60 to 90 degreeC is more preferable. When the melting point is less than 40 ° C., the heat resistant storage stability is adversely affected. When the melting point exceeds 160 ° C., a cold offset tends to occur during fixing at a low temperature.

  The melt viscosity of the wax is preferably 5 cps to 1,000 cps, more preferably 10 cps to 100 cps, as a measured value at a temperature 20 ° C. higher than the melting point. When the melt viscosity is less than 5 cps, the wax tends to ooze out on the toner surface, and the fluidity and storage stability of the toner may be deteriorated. When it exceeds 1,000 cps, hot offset resistance and low temperature fixability Poor improvement effect.

  The content of the wax in the toner is usually 0% by mass to 40% by mass, and preferably 3% by mass to 30% by mass. When the content exceeds 40% by mass, the storage stability of the toner may be deteriorated and the fixability may be deteriorated (the toner after fixing is easily peeled off from the paper).

The toner used in the present invention may contain a charge control agent as necessary in order to accelerate the toner charge amount and its rise. Here, since a color change occurs when a colored material is used as the charge control agent, a material that is colorless and close to white is preferable.
The charge control agent is not particularly limited, and known ones can be used. Examples thereof include triphenylmethane dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified quaternary ammonium salts). Salt), alkylamide, phosphorus simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, and metal salt of salicylic acid derivative. As these commercial products, for example, Bontron P-51 of quaternary ammonium salt, E-82 of oxynaphthoic acid metal complex, E-84 of salicylic acid metal complex, E-89 of phenol condensate (above , Manufactured by Orient Chemical Co., Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, manufactured by Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy charge PSY VP2038, triphenylmethane Copy blue PR of derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (above, manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (manufactured by Nippon Carlit Co., Ltd.), quinacridone, Azo pigments, other sulfonic acid groups, carboxyl groups, quaternary amines Polymeric compounds having a functional group such as salt and the like.

  The content of the charge control agent is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method. Although it is not, 0.1 mass part-10 mass parts are preferable with respect to 100 mass parts of binder resin, and 0.2 mass part-5 mass parts are more preferable. When the content exceeds 10 parts by mass, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, and the fluidity of the developer is lowered. The image density may be lowered.

  The charge control agent may be dissolved and dispersed after being melt-kneaded with a masterbatch and a resin, or may be added when directly dissolving and dispersing in an organic solvent, or may be fixed on the toner surface after preparation of toner particles. Also good.

The toner used in the present invention may contain resin fine particles mainly for stabilizing the dispersion when the toner composition is dispersed in the aqueous medium during the production process.
The resin fine particles are not particularly limited, and any resin can be used as long as it can form an aqueous dispersion, and may be a thermoplastic resin or a thermosetting resin. For example, vinyl resin, polyurethane resin, epoxy Examples thereof include resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, and polycarbonate resins. These may be used individually by 1 type and may use 2 or more types together. Among these, a vinyl resin, a polyurethane resin, an epoxy resin, a polyester resin, and a combination thereof are preferable in that an aqueous dispersion of fine spherical resin particles can be easily obtained.

  The vinyl resin is not particularly limited as long as it is a polymer obtained by homopolymerization or copolymerization of a vinyl monomer, and can be appropriately selected according to the purpose. For example, styrene- (meth) acrylate resin, styrene -Butadiene copolymer, (meth) acrylic acid-acrylic acid ester polymer, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, styrene- (meth) acrylic acid copolymer and the like.

Furthermore, inorganic fine particles can be suitably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles.
The inorganic fine particles are not particularly limited and may be appropriately selected from known ones according to the purpose. Examples thereof include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, and titanic acid. Strontium, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, carbonized Examples thereof include silicon and silicon nitride. In addition to these, polymer fine particles such as polystyrene, methacrylic acid ester, acrylic acid ester copolymer, silicone, benzoguanamine, nylon and the like obtained by soap-free emulsion polymerization, suspension polymerization, dispersion polymerization, etc. It is also possible to use polymer particles made of a condensation system or a thermosetting resin.

  The external additive can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. The surface treatment agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, and organic titanate cups. A ring agent, an aluminum-based coupling agent, silicone oil, modified silicone oil and the like are preferable.

  The primary particle diameter of the inorganic fine particles is preferably 5 nm to 2 μm, and more preferably 5 nm to 500 μm. If the primary particle size is less than 5 nm, it may be difficult to remove from the surface of the image carrier, and if it exceeds 2 μm, it may be difficult to adhere to the toner and be released.

The BET specific surface area of the inorganic fine ^particles, 20m ² / ^g~500m 2 / g are preferred. When the specific surface area is less than 20 m ² / g, the toner may be released from the toner, and when it exceeds 500 m ² / g, the image carrier may be easily damaged.

  The content of the inorganic fine particles in the toner is preferably 0.01% by mass to 5% by mass, and more preferably 0.01% by mass to 2% by mass. When the content is less than 0.01% by mass, it may be difficult to obtain an effect of assisting fluidity, developability, and chargeability of the toner particles. When the content exceeds 5% by mass, for fixing, A greater amount of heat may be required.

  Further, examples of the cleaning property improving agent for removing the developer after transfer remaining on the photoreceptor or primary transfer medium, which may be contained in the toner used in the present invention, include zinc stearate, calcium stearate, stearin. Examples thereof include fatty acid metal salts such as acids, polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles have a relatively narrow particle size distribution, and the volume average particle size is preferably 0.01 μm to 1 μm.

By using the toner described above, it is possible to form a high-quality toner image having excellent development stability. However, the toner that is not transferred to the transfer medium or intermediate transfer medium by the transfer device and remains on the image carrier is difficult to remove by the cleaning device due to its fineness and good rolling properties. May end up. In order to completely remove the toner from the image carrier, it is necessary to strongly press a toner removing member such as a cleaning blade against the image carrier. Such a load not only shortens the life of the image carrier and the cleaning device, but also uses extra energy.
When the load on the image carrier is reduced, the toner and the small-diameter carrier on the image carrier are not sufficiently removed, and these damage the surface of the image carrier when passing through the cleaning device. It becomes a factor which fluctuates performance.
As will be described later, the process cartridge and the image forming apparatus of the present invention have excellent tolerance for fluctuations in the surface state of the image carrier, in particular, the presence of a low resistance portion, and fluctuations in charging performance to the image carrier, etc. Since the configuration is highly suppressed, an image with extremely high image quality can be stably obtained over a long period of time when used in combination with the toner having the above configuration.

  In addition, the production method of the present invention can be applied not only to the use of the toner having a configuration suitable for obtaining a high-quality image as described above, but also to an irregular shaped toner by a pulverization method. Needless to say, the life of the body, the cleaning member and the like is greatly extended.

As the material constituting the pulverized toner, those usually used as an electrophotographic toner can be applied without particular limitation.
Examples of the general binder resin used in the toner include homopolymers of styrene such as polystyrene, poly p-chlorostyrene, and polyvinyltoluene, and substitution products thereof; styrene / p-chlorostyrene copolymers, Styrene / propylene copolymer, styrene / vinyl toluene copolymer, styrene / vinyl naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, Styrene / octyl acrylate copolymer, styrene / methyl methacrylate copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / α-chloromethyl methacrylate copolymer, styrene / Acrylonitrile copolymer, styrene / vinyl methyl ketone copolymer Styrene copolymers such as styrene / butadiene copolymer, styrene / isoprene copolymer, styrene / maleic acid copolymer; polymethyl acrylate, polybutyl acrylate, polymethyl methacrylate, polybutyl methacrylate Acrylic ester-based homopolymers and copolymers thereof; polyvinyl derivatives such as polyvinyl chloride and polyvinyl acetate; polyester-based polymers, polyurethane-based polymers, polyamide-based polymers, polyimide-based polymers, polyol-based polymers Examples thereof include a polymer, an epoxy polymer, a terpene polymer, an aliphatic or alicyclic hydrocarbon resin, and an aromatic petroleum resin. These may be used individually by 1 type and may use 2 or more types together. Among these, at least one selected from styrene-acrylic copolymer resins, polyester resins, and polyol resins is preferable from the viewpoint of electrical characteristics, cost, and the like. Furthermore, at least one of a polyester-based resin and a polyol-based resin is even more preferable in terms of having good fixing characteristics.

  For the reasons described above, as the resin component contained in the coating layer of the charging member, the same resin component as that constituting the binder resin of the toner can be used, and a linear polyester resin composition, a linear polyol can be used. At least one of a resin composition, a linear styrene acrylic resin composition, and a crosslinked product thereof can be suitably used.

  In the toner by the pulverization method, a colorant component, a release agent component, a charge control agent component, and the like as described above are added as necessary together with the resin component described above, and then the temperature is not higher than the melting temperature of the resin component. After kneading and cooling, a toner may be prepared through a pulverization and classification step, and the above-mentioned external additive components may be added and mixed as necessary.

-Image carrier-
The image carrier used in the present invention is generally a photoconductor, but may be an intermediate transfer medium in the case of an intermediate transfer type image forming method.

--Photoconductor--
The photoreceptor is formed by providing a photosensitive layer on a conductive support. Examples of the photosensitive layer structure include a single layer type in which a charge generation material and a charge transport material are mixed, a forward layer type in which a charge transport layer is provided on the charge generation layer, and a charge generation on the charge transport layer. The reverse layer type which provided the layer is mentioned.
The photoconductor may be provided with a protective layer on the photoconductive layer in order to improve the mechanical strength, wear resistance, gas resistance, cleaning properties, etc. of the photoconductor. An undercoat layer may be provided between the photosensitive layer and the conductive support. Furthermore, an appropriate amount of a plasticizer, an antioxidant, a leveling agent, and the like can be added to each layer as necessary.

Examples of the conductive support for the photoreceptor include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum and other metals, tin oxide , Metal oxide such as indium oxide, film or cylindrical plastic coated by vapor deposition or sputtering, paper, etc., aluminum, aluminum alloy, nickel, stainless steel plates and the like, and extruding, drawing, etc. After making the pipe into a drum shape by the construction method, it is possible to use a pipe that has been surface-treated by cutting, superfinishing, polishing, or the like. Further, endless nickel belts and endless stainless steel belts described in JP-A-52-36016 can also be used as the conductive support.

  The diameter of the drum-shaped support is preferably 20 mm to 150 mm, more preferably 24 mm to 100 mm, and particularly preferably 28 mm to 70 mm. When the diameter of the drum-shaped support is less than 20 mm, it is physically difficult to arrange each process such as charging, exposure, development, transfer, and cleaning around the drum. When the diameter exceeds 150 mm, the image forming apparatus There is a problem that becomes large. In particular, when the image forming apparatus is a tandem type, since it is necessary to mount a plurality of photoconductors, the diameter is preferably 70 mm or less, and more preferably 60 mm or less.

The undercoat layer of the photoconductor is not particularly limited and can be appropriately selected from known ones. For example, a resin, a white pigment and a resin as a main component, and a surface of a conductive substrate are chemically treated. Examples thereof include a metal oxide film that has been subjected to chemical or electrochemical oxidation. Among these, those containing a white pigment and a resin as main components are preferable. The undercoat layer may be a single layer or a plurality of layers.
Examples of the white pigment include metal oxides such as titanium oxide, aluminum oxide, zirconium oxide, and zinc oxide. Among these, titanium oxide is particularly preferable because it is excellent in preventing charge injection from a conductive substrate. These may be used alone or in combination of two or more.
There is no restriction | limiting in particular as resin used for the said undercoat layer, It can select suitably from well-known things, For example, thermoplastic resins, such as a polyamide, polyvinyl alcohol, casein, methylcellulose, an acryl, a phenol, a melamine, an alkyd , Thermosetting resins such as unsaturated polyesters and epoxies, and one or various mixtures thereof.

  The charge generating material of the photoreceptor is not particularly limited and can be appropriately selected from known materials. For example, azo pigments such as monoazo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments, and tria Lille methane dye, thiazine dye, oxazine dye, xanthene dye, cyanine dye, styryl dye, pyrylium dye, quinacridone pigment, indigo pigment, perylene pigment, polycyclic quinone pigment, bisbenzimidazole Organic pigments and dyes such as pigments, indanthrone pigments, squarylium pigments, phthalocyanine pigments, inorganic materials such as selenium, selenium-arsenic, selenium-tellurium, cadmium sulfide, zinc oxide, titanium oxide, amorphous silicon, etc. Is mentioned. These may be used alone or in combination of two or more.

  The charge transport material of the photoreceptor is not particularly limited and can be appropriately selected from known materials. For example, anthracene derivatives, pyrene derivatives, carbazole derivatives, tetrazole derivatives, metallocene derivatives, phenothiazine derivatives, pyrazoline compounds, Hydrazone compounds, styryl compounds, styryl hydrazone compounds, enamine compounds, butadiene compounds, distyryl compounds, oxazole compounds, oxadiazole compounds, thiazole compounds, imidazole compounds, triphenylamine derivatives, phenylenediamine derivatives, aminostilbene derivatives, triphenylmethane derivatives Etc. These may be used alone or in combination of two or more.

  The binder resin used to form the photosensitive layer of the charge generation layer and the charge transport layer is electrically insulating and is a known thermoplastic resin, thermosetting resin, photocurable resin, and photoconductive material. Suitable binder resins include, for example, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, Ethylene-vinyl acetate copolymer, polyvinyl butyral, polyvinyl acetal, polyester, phenoxy resin, (meth) acrylic resin, polystyrene, polycarbonate, polyarylate, thermoplastic resin such as polysulfone, polyethersulfone, ABS resin, phenol resin , Epoxy resin, urethane resin, melamine resin, isocyanate resin, alkyd resin, Examples thereof include a thermosetting resin such as a ricone resin, a thermosetting acrylic resin, a type of binder resin such as a photoconductive resin such as polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene, or a mixture of various types of binder resins. In particular, it is not limited to these.

  The antioxidant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di- monophenolic compounds such as t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 3-t-butyl-4-hydroxynisol, 2 , 2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4'-thiobis- (3 -Methyl-6-t-butylphenol), bisphenol compounds such as 4,4′-butylidenebis- (3-methyl-6-t-butylphenol), 1,1,3-tris- (2- Til-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis- [Methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3′-t-butylphenyl) Butyric acid] glycol ester, polymer phenolic compounds such as tocophenols, N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N— Phenyl-N-sec-butyl-p-phenylenediamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N ′ -Paraphenylenediamines such as di-t-butyl-p-phenylenediamine, 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, Hydroquinones such as 2-t-octyl-5-methylhydroquinone and 2- (2-octadecenyl) -5-methylhydroquinone, dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipro Organic sulfur compounds such as pionate, ditetradecyl-3,3′-thiodipropionate, triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4 -Organophosphorus compounds such as dibutylphenoxy) phosphine And the like.

There is no restriction | limiting in particular as said plasticizer, According to the objective, it can select suitably, For example, what is used as plasticizers of common resin, such as dibutyl phthalate and dioctyl phthalate, can be used as it is.
The content of the plasticizer is preferably about 0 to 30 parts by mass with respect to 100 parts by mass of the binder resin.

A leveling agent may be further added to the charge transport layer.
Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the chain.
The addition amount of the leveling agent is preferably 0 to 1 part by mass with respect to 100 parts by mass of the binder resin.

As described above, the surface layer is provided to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, and the like of the photoreceptor. Examples of the surface layer include a polymer having higher mechanical strength than the photosensitive layer, and a polymer in which an inorganic filler is dispersed. There is no restriction | limiting in particular as a polymer used for the said surface layer, According to the objective, it can select suitably, For example, a thermoplastic polymer, a thermosetting polymer, etc. are mentioned. Among these, thermosetting polymers are particularly preferable because they have high mechanical strength and extremely high ability to suppress wear due to friction with the cleaning blade.
If the surface layer has a thin film thickness, there is no problem even if it does not have the charge transport capability, but if the surface layer without the charge transport capability is formed thick, the sensitivity of the photoreceptor decreases and the potential increases after exposure. Since the residual potential is likely to increase, it is preferable to use the above-described charge transport material in the surface layer or to use a polymer having charge transport capability for the protective layer.
Since the mechanical strength of the photosensitive layer and the surface layer is generally greatly different, the protective layer is worn away by friction with the cleaning blade, and when it disappears, the photosensitive layer is worn immediately. For this, it is important that the surface layer has a sufficient thickness. The average thickness of the surface layer is preferably 0.1 μm to 12 μm, more preferably 1 μm to 10 μm, and particularly preferably 2 μm to 8 μm. When the film thickness is less than 0.1 μm, the surface layer is too thin and is likely to disappear partially due to friction with the cleaning blade, and wear of the photosensitive layer may proceed from the disappeared portion. When the film thickness of the surface layer exceeds 12 μm, a sensitivity drop, a post-exposure potential increase, and a residual potential increase are likely to occur. Particularly when a polymer having a charge transport capability is used, the polymer having a charge transport capability The cost of will become high.

  The polymer used for the surface layer is preferably a polymer that is transparent to writing light during image formation and excellent in insulation, mechanical strength, and adhesion. Examples of such a polymer include ABS resin. , ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene , Polyethylene terephthalate, polyimide, acrylic resin, polymethyl bentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinyl chloride Alkylidene, such as an epoxy resin. These polymers may be thermoplastic polymers, but in order to increase the mechanical strength of the polymers, they are crosslinked with a crosslinking agent having a polyfunctional acryloyl group, carboxyl group, hydroxyl group, amino group, etc. By using a thermosetting polymer, the mechanical strength of the surface layer can be increased, and wear due to friction with the cleaning blade can be greatly reduced.

  As described above, the surface layer preferably has a charge transport capability. In order to provide the surface layer with a charge transport capability, the polymer used for the surface layer and the charge transport material described above are mixed. And a method using a polymer having a charge transporting capability for the surface layer. Among these, the latter method is preferable in that a photoconductor with high sensitivity and little increase in post-exposure potential and residual potential can be obtained.

--Intermediate transfer medium--
The image carrier in the present invention is an intermediate transfer used when image formation is performed by a so-called intermediate transfer method in which a toner image formed on a photosensitive member is primarily transferred to perform color superposition and further transferred to a transfer medium. It may be a medium.

The intermediate transfer medium is not particularly limited and may be appropriately selected from known ones. For example, metal oxides such as tin oxide and indium oxide, conductive particles such as carbon black, and conductive polymers may be used. A belt-like or cylindrical plastic that has been kneaded with a thermoplastic resin alone or in combination, and then extruded can be used. In addition, the above-mentioned conductive particles and conductive polymer are added to a resin solution containing a thermal crosslinking reactive monomer or oligomer, if necessary, and subjected to centrifugal molding while heating to obtain an intermediate transfer medium on an endless belt. You can also
In addition, when a surface layer is provided on the intermediate transfer medium, the resistance is adjusted by appropriately using a conductive substance in combination with the composition excluding the charge transport material among the surface layer materials used for the above-described photoreceptor surface layer. Can be used.

The conductivity of the intermediate transfer medium is preferably 10 ⁵ Ω · cm to 10 ¹¹ Ω · cm in terms of volume resistance. If the volume resistance is less than 10 ⁵ Ω · cm, so-called transfer dust may occur in which the toner image is disturbed due to discharge when the toner image is transferred from the photoreceptor onto the intermediate transfer medium. ^If it exceeds ¹¹ Ω · cm, after transferring the toner image from the intermediate transfer medium to a transfer medium such as paper, the counter charge of the toner image may remain on the intermediate transfer medium and appear as an afterimage on the next image. .

<Protective layer forming step>
The image forming method of the present invention may further include a protective layer forming step of pressing the image carrier protecting agent component supplied to the surface of the image carrier to form a film.
When the image carrier protecting agent component forms a protective layer on the surface of the image carrier, the friction coefficient between the image carrier and the cleaning member can be reduced, and the occurrence of defective cleaning can be suppressed. Further, the transfer rate can be increased by reducing the interaction between the image carrier and the toner and making the toner on the image carrier easier to separate.

  The blade material used for pressing the image carrier protective agent component in the protective layer forming step is not particularly limited and may be appropriately selected depending on the purpose. For example, it is generally known as a cleaning blade material. Elastic bodies such as urethane rubber, hydrin rubber, silicone rubber, and fluoro rubber can be used singly or in a blend. Further, these rubber blades may be coated or impregnated using a low friction coefficient material at the contact portion with the image carrier. Further, in order to adjust the hardness of the elastic body, fillers represented by other organic fillers and inorganic fillers may be dispersed.

The blade is fixed to the blade support by any method such as adhesion or fusion so that the tip can be pressed against the surface of the image carrier.
The thickness of the blade is not uniquely defined by the balance with the force applied by pressing, but is preferably about 0.5 mm to 5 mm, more preferably about 1 mm to 3 mm.
Further, the length of the cleaning blade that protrudes from the blade support and can bend, that is, the so-called free length, is not uniquely defined by the balance with the force applied by pressing, as described above. However, approximately 1 mm to 15 mm is preferable, and approximately 2 mm to 10 mm is more preferable.

Other configurations of the blade member for forming the protective layer include coating, dipping, etc. with a layer of resin, rubber, elastomer, etc. on the surface of an elastic metal blade such as a spring plate, if necessary, via a coupling agent, primer component, etc. It may be formed by a method, heat-cured, etc. if necessary, and if necessary, may be subjected to surface polishing or the like.
There is no restriction | limiting in particular as thickness of the said elastic metal braid | blade, Although it can select suitably according to the objective, About 0.05 mm-3 mm are preferable, About 0.1 mm-1 mm are more preferable.
Moreover, in an elastic metal blade, in order to suppress the twist of a braid | blade, you may perform processes, such as a bending process, in the direction substantially parallel to a spindle after attachment.
There is no restriction | limiting in particular as a material which forms the surface layer of the said elastic metal blade, According to the objective, it can select suitably, For example, fluororesins, such as PFA, PTFE, FEP, PVdF, fluororubber, methylphenyl Examples include silicone elastomers such as silicone elastomers, and these can be used together with a filler as necessary.

  As a force (pressing force) for pressing the image carrier in the protective layer forming step, a force that spreads the protective agent to form a protective layer (protective film) is sufficient, and the linear pressure is 5 gf / cm to 80 gf. / Cm is preferable, and 10 gf / cm to 60 gf / cm is more preferable. When the pressing force is less than 5 gf / cm, the protective agent does not sufficiently spread and may not be in a layer (film) state. When it exceeds 80 gf / cm, the blade hits the belly. The protective agent may pass through the blade more than necessary.

<Charging process>
The image forming method of the present invention may include, in addition to the developing step, a charging step in which the image carrier is charged by a charging unit disposed in contact with or close to the surface of the image carrier.

The charging step can be performed, for example, by applying a voltage to the surface of the image carrier using a charging unit.
The charging means is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charger including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers utilizing corona discharge such as corotron and scorotron.

The charging means is arranged in contact or non-contact with an electrostatic latent image carrier (hereinafter also referred to as “image carrier” to “photoconductor”), and applies a voltage having an AC component. It is preferable to charge the surface of the support by this.
The charging means is a charging roller that is disposed in close proximity to the electrostatic latent image carrier via a gap tape, and the surface of the image carrier is applied by applying a voltage having an AC component to the charging roller. Those that charge are preferable.

(Process cartridge)
The process cartridge of the present invention comprises at least an image carrier that carries an electrostatic latent image and a developing unit that develops the electrostatic latent image carried on the carrier with a developer. Other means appropriately selected as necessary are provided.
The developer used in the developing unit is as described above, and includes an image carrier protecting agent component containing a fatty acid metal salt, and a lubricant component comprising at least one of silica, alumina, acrylic particles, and boron nitride. It contains granules and toner. The image carrier and charging means in the process cartridge of the present invention are as described above.
The process cartridge can be detachably provided in various electrophotographic image forming apparatuses, and is detachably provided in an image forming apparatus of the present invention described later.

The process cartridge of the present invention may further include a container for containing the developer, and the container contains the developer described above.
There is no restriction | limiting in particular as said container, Although it can select suitably according to the objective, What has a developer container main body and a cap is preferable.
The size, shape, structure, material and the like of the developer container main body are not particularly limited and may be appropriately selected depending on the purpose. For example, the shape is preferably cylindrical. , Spiral irregularities are formed on the inner peripheral surface, the toner as the contents can be transferred to the discharge port side by rotating, and a part or all of the spiral part has a bellows function Is particularly preferred.
The material of the developer container main body is not particularly limited and may be appropriately selected depending on the intended purpose. However, a material having good dimensional accuracy is preferable. For example, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, Resins such as vinyl chloride resin, polyacrylic acid, polycarbonate resin, ABS resin, and polyacetal resin are preferred.

Here, for example, as shown in FIG. 1, the process cartridge includes an electrostatic latent image carrier 101, and includes a charging unit 102, a developing unit 104, a transfer unit 108, and a cleaning unit 107, and further, if necessary. And other means. In FIG. 1, reference numeral 103 denotes exposure by exposure means, and 105 denotes a recording medium.
Next, the image forming process using the process cartridge shown in FIG. 1 will be described. The electrostatic latent image carrier 101 is charged by the charging unit 102 while being rotated in the direction of the arrow, and exposure 103 by the exposure unit (not shown). An electrostatic latent image corresponding to the exposure image is formed on the surface. The electrostatic latent image is developed by the developing unit 104, and the obtained visible image is transferred to the recording medium 105 by the transfer unit 108 and printed out. Next, the surface of the latent electrostatic image bearing member after the image transfer is cleaned by the cleaning unit 107, further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

(Image forming device)
The image forming apparatus of the present invention includes the process cartridge, and may have other configurations as necessary. There is no restriction | limiting in particular as said other structure, According to the objective, it can select from a well-known thing suitably.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, the form of this invention is not limited to this.

(Examples 1 to 29)
The image carrier protective agent component and the lubricant component were mixed and granulated so as to have the composition and mixing ratio shown in Table 1.
For the granulation, a roller compactor RC-MINI (manufactured by Freund Sangyo Co., Ltd.) is used, and the roll rotation speed is 2 rpm to 10 rpm, the molding pressure is 2,000 kg to 6, so that the particle diameter shown in Table 1 is obtained. Granulated under the condition of 000 kg. The particle size of the obtained granulated product was measured using a laser diffraction particle size distribution analyzer (SALD-2200, manufactured by Shimadzu Corporation), and the value of the median diameter D50 was defined as the average particle size.
The obtained granulated product was added to the toner for imgio MP C4500 manufactured by Ricoh Co., Ltd. so as to have an addition amount (mass%) shown in Table 1 to obtain a developer for use in image formation.
When the granulated product was added to the toner, it was mixed for 5 minutes using a tumbler mixer (T2F type, manufactured by Willy A Bachofen AG).
Table 2 shows the amount of the granulated material added to the toner converted to the amount of the image carrier protecting agent component and the lubricant component added to the toner.

As the image forming apparatus, an image forming unit of imgio MP C4500 manufactured by Ricoh Co., Ltd. uses a device for removing zinc stearate and a coating blade, and the granulation is applied to the toner in the toner cartridge of the apparatus. Things were put into a developer.
For a document with an image area ratio of 5%, A4 size paper (My Paper, manufactured by Ricoh Co., Ltd.) was used, and a continuous paper passing test of 2,000 sheets was conducted. Cleaning performance (toner slipping), charging member contamination, photosensitivity Body protection and development follow-up were evaluated as follows.

<Cleanability>
After conducting a continuous sheet passing test of 2,000 sheets, the surface of the photoreceptor of the image forming apparatus and the 2,000th sheet are observed, and the presence or absence of toner slip and the presence or absence of abnormal images are evaluated according to the following criteria. did. The results are shown in Table 3.
〔Evaluation criteria〕
◎: There is almost no toner slipping and no abnormal image is generated. ○: There is toner slipping out, but the image cannot be recognized. △: Many toner slips out, and the image has clear streaks. Here, there are many slips and streaks are frequently generated in the image. Here, the abnormal image refers to an image in which the toner that has passed through the cleaning member appears as a streak.

<Contamination of charging means>
After conducting a continuous sheet passing test of 2,000 sheets, the charging unit of the image forming apparatus and the 2,000th sheet of paper were observed, and the presence or absence of contamination of the charging unit and the presence or absence of abnormal images were evaluated according to the following criteria. did. In the paper passing test, evaluation was performed by changing environmental conditions so as to be in a normal temperature environment (temperature: 23 ° C., humidity: 50%) and in a low temperature environment (temperature: 10 ° C., humidity: 15%). did. The results are shown in Table 3.
〔Evaluation criteria〕
◎: The charging unit is almost free of dirt and no abnormal image is generated. ○: The charging unit is slightly dirty, but there is no effect on the image in a normal temperature environment. △: The charging unit is dirty and an abnormal image is generated in a low temperature environment. Yes: The charging means is dirty, and an abnormal image is generated at an early stage. Note that the early stage indicates that the number is 1,000 or less.

<Photoconductor protection>
After conducting a continuous sheet passing test of 2,000 sheets, the surface of the photoreceptor of the image forming apparatus and the 2,000th sheet were observed, and the presence or absence of filming and the presence or absence of abnormal images were evaluated according to the following criteria. . The results are shown in Table 3.
〔Evaluation criteria〕
A: There is almost no filming and no abnormal image occurs. ○: There is a slight filming, but there is no abnormality in the image. Δ: There is filming, and an abnormal image occurs. Here, an abnormal image occurs. Here, an abnormal image refers to an image in which an image omission occurs, and a severe abnormal image refers to an image having a large range, frequency, etc. of image omission.

<Development followability>
Under the conditions of a high image area (image area ratio 50%) and a low image area (image area ratio 5%), after conducting a continuous sheet passing test of 2,000 sheets, the 2,000th sheet was observed, Followability was evaluated according to the following criteria. The results are shown in Table 3.
〔Evaluation criteria〕
◎: Follow up even in a high image area ○: Slight follow-up failure occurs in a high image area △: A lot of follow-up failure occurs in a high image area ×: Follow-up does not occur even in a low image area For an electrostatic latent image, supplying sufficient toner between the development nips to develop the latent image. Specifically, poor tracking specifically refers to image blurring or a decrease in image density. To do.

(Comparative Examples 1-20)
In Comparative Example 1, the above various evaluations were performed without adding the image carrier protecting agent component and the lubricant component to the toner. The results are shown in Table 3.
Further, in Comparative Examples 2 to 20, the image carrier protective agent component and the lubricant component were not granulated, and the addition amount (% by mass) with respect to the toner was added to the toner so that the ratio shown in Table 2 was obtained. Were the same as in Examples 1 to 29, and a developer was prepared and subjected to the various evaluations described above. The results are shown in Table 3.

Details of the image carrier protecting agent component and the lubricant component used in Examples 1 to 29 and Comparative Examples 1 to 20 are shown below.
Zinc stearate: GF200, manufactured by Nippon Oil & Fats Co., Ltd. Calcium stearate: manufactured by Wako Pure Chemical Industries, Ltd. Zinc laurate: manufactured by Wako Pure Chemical Industries, Ltd. Silica: X24, manufactured by Shin-Etsu Chemical Co., Ltd., volume average particle size 0.2 μm
Alumina: AA03, manufactured by Sumitomo Chemical Co., Ltd., volume average particle size 0.3 μm
Acrylic particles: MP-1000, manufactured by Soken Chemical Co., Ltd., volume average particle size 0.4 μm
Boron nitride: NX5, manufactured by Momentive Performance Materials, volume average particle size 5 μm

The image forming method of the present invention is considered to realize toner slipping, charging means contamination, image carrier filming prevention and development follow-up for the following reasons.
The electrophotographic image carrier is coated with a protective agent to protect the image carrier from charging and cleaning hazards. However, generally used fatty acid metal salts have poor lubricity due to the effect of charging, and toner passes through the cleaning member, resulting in poor cleaning. Further, the fatty acid metal salt itself flies to and adheres to the charging means, causing charging member contamination.
Therefore, by adding at least one of silica, alumina, acrylic particles, and boron nitride, lubricity can be assisted and toner slippage can be prevented. Further, the improvement in lubricity can reduce the amount of the fatty acid metal salt itself that slips through, and the amount of the fatty acid metal salt flying to the charging member can be reduced.
Due to this effect, the cleaning property is improved in all of the comparative examples and examples to which at least one of silica, alumina, acrylic particles and boron nitride is added.

However, for example, in the case where the fatty acid metal salt is not supplied as in Comparative Example 1 and Comparative Examples 5 to 16, the protective property of the photoreceptor is remarkably lowered. Further, even when the fatty acid metal salt is supplied as in Comparative Examples 17 to 20, the protective properties of the photoreceptor are lowered even when other lubricant components are supplied without granulating with the fatty acid metal salt. To do.
This is because the lubricant component once supplied onto the photosensitive member is difficult to be removed because there are many free lubricant components.
Further, when the fatty acid metal salt is added without granulation as in Comparative Examples 2 to 4 and Comparative Examples 17 to 20, the fluidity of the developer is lowered, and thus the developing ability is lowered. If the amount of fatty acid metal salt added is small as in Comparative Example 2, the decrease in fluidity can be suppressed, but conversely, the photoreceptor cannot be protected.

  When Examples 1 to 4 and Examples 5 to 12 are compared, zinc stearate is superior in photoconductor protection compared to other fatty acid metal salts. Of the higher fatty acids, stearic acid is the least expensive, and zinc salt is a very stable substance with excellent hydrophobicity.

  From the results of Examples 25 to 29, the particle size of the granulated product can be 10 μm to 100 μm, but 20 μm to 40 μm is more preferable in terms of development followability and photoreceptor protection.

Since the image carrier protecting agent used in the present invention is difficult to be formed on the image carrier simply by being supplied, higher protection performance is exhibited by installing a layer forming member.
Moreover, since the surface in which at least one of alumina and silica is dispersed forms irregularities, the protective agent is easily retained, and the protective property is improved.
Further, when the image carrier includes a thermosetting resin in at least the layer formed on the outermost surface, the image carrier is prevented from deteriorating due to electrical stress with a protective agent, thereby including the thermosetting resin. The durability of the image carrier against mechanical stress can be sustained over a long period of time. As a result, the durability of the image carrier can be increased to a level where it can be used substantially without replacement.
Further, in the case where the charging means is disposed in contact with or close to the surface of the image carrier, the electrical stress tends to increase because the discharge region exists very close to the image carrier. The image forming method of the present invention in which the carrier protective layer is formed can be used without exposing the image carrier to electrical stress.
Furthermore, since the surface of the image carrier can be made to have a very small change in surface state due to the effect of the protective layer formed on the surface, the average quality is such that the quality of cleaning varies sensitively to the change in state of the image carrier. Even a toner having a large degree of circularity or a toner having a small average particle diameter can be stably cleaned over a long period of time.

In the image forming method of the present invention, the protective agent or lubricant molded in the form of a block is scraped off with a brush roller or the like and supplied to the surface of the image carrier, and the image carrier protective agent from the developer is used. Further, only by supplying the lubricant, it is possible to prevent wear and filming of the image carrier, contamination of the charging member, and toner slip-through, and it is possible to stably obtain a good quality image over a long period of time.
In the process cartridge and the image forming apparatus of the present invention, the process cartridge is configured using a granulated material containing the image carrier protecting agent and the lubricant, so that the process cartridge replacement interval is set to be extremely long. Therefore, the running cost is reduced and the amount of waste can be greatly reduced. In particular, when the image carrier includes a thermosetting resin in at least the layer formed on the outermost surface, the image carrier is prevented from being deteriorated by an electrical stress, and the thermosetting property is prevented. The durability of the image bearing member including the resin against mechanical stress can be continuously expressed over a long period of time. For this reason, it becomes easy to reuse process cartridge components such as an image carrier and a charging member, and the amount of waste can be further reduced.

101 Electrostatic latent image carrier (photosensitive member)
102 Charging means 103 Exposure 104 Developing means 105 Recording medium 107 Cleaning means 108 Transfer means

Japanese Patent Publication No.51-22380 JP 2007-304246 A JP 2004-333961 A JP 2000-19773 A

Claims (16)

A development step of developing the electrostatic latent image formed on the image carrier with a developer;
The developer is
An image carrier protective agent component containing a fatty acid metal salt, and a granulated product containing a lubricant component consisting of at least one of silica, alumina, acrylic particles and boron nitride;
An image forming method comprising a toner.   The image forming method according to claim 1, wherein the fatty acid metal salt is zinc stearate.   The image forming method according to claim 1, further comprising a protective layer forming step of pressing the image carrier protecting agent component supplied to the surface of the image carrier to form a film.   The image forming method according to any one of claims 1 to 3, wherein the image carrier comprises a thermosetting resin in at least a layer formed on the outermost surface.   The image forming method according to claim 1, wherein the image carrier is a photoconductor.   6. The image forming method according to claim 1, further comprising a charging step of charging the image carrier by a charging unit disposed in contact with or in proximity to the surface of the image carrier.   The image forming method according to claim 6, wherein the charging unit includes a voltage applying unit that applies a voltage having an AC component. The image forming method according to claim 1, wherein the toner has an average circularity (SR) represented by the following formula (1) of 0.93 to 1.00.
Circularity (SR) = perimeter of a circle having the same area as the particle projection area / perimeter of the particle projection image (1)   The image forming method according to claim 1, wherein a ratio (D4 / D1) of the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner is 1.00 to 1.40. At least an image carrier that carries an electrostatic latent image and a developing unit that develops the electrostatic latent image with a developer;
The developer is
An image carrier protective agent component containing a fatty acid metal salt, and a granulated product containing a lubricant component consisting of at least one of silica, alumina, acrylic particles and boron nitride;
A process cartridge containing toner.   The process cartridge according to claim 10, wherein the image carrier includes a thermosetting resin in at least a layer formed on the outermost surface.   12. The process cartridge according to claim 10, further comprising a charging unit disposed in contact with or close to the surface of the image carrier.   The process cartridge according to claim 10, further comprising a container containing a developer. 14. The process cartridge according to claim 10, wherein the toner has an average circularity (SR) represented by the following formula (1) of 0.93 to 1.00.
Circularity (SR) = perimeter of a circle having the same area as the particle projection area / perimeter of the particle projection image (1)   The process cartridge according to any one of claims 10 to 14, wherein a ratio (D4 / D1) of the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner is 1.00 to 1.40.   An image forming apparatus comprising the process cartridge according to claim 10.

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