JP4469748B2 - Image forming method - Google Patents

Description

  The present invention relates to an image forming method used in a recording method using an electrostatic recording method or the like. More specifically, the present invention relates to an image forming method used in a copying machine, a printer, and a fax machine in which an electrostatic latent image formed on an electrostatic latent image carrier is developed with toner and then transferred onto a transfer material to form an image.

As an electrophotographic method, a photoconductive substance is generally used, and an electrostatic charge latent image is formed on a photoreceptor by various means. The latent image is then developed with toner, and a recording material such as paper (transfer material) After the toner image is transferred to the material, the toner remaining on the photoconductor is removed if necessary, and at the same time, the toner image on the transfer material is fixed by heating, pressure, heating pressure or solvent vapor to obtain a toner image. It is.
In recent years, an electronic photograph using a digital system that converts reflected light of an original into an electrical signal, processes the signal, and then directly irradiates a photoreceptor with laser light, LED light, etc. to form a latent image, Electrostatic recording systems have been commercialized.

  In many electrophotographic systems that use digital image signals, a light emitter (such as a semiconductor laser) is turned on and off (ON-OFF) in accordance with the image signal, and the light is projected onto a photoconductor. In this case, the printing rate (the ratio of the printing area per page) is usually 30% or less, and the so-called reversal development in which the character portion is exposed is advantageous in terms of the life of the light emitter.

Further, when a digital reversal latent image is formed using a semiconductor laser or the like, a photosensitive drum having a spectral sensitivity in the infrared region near 800 nm is used.
As a photoconductor having spectral sensitivity in this region, there is an amorphous silicon (hereinafter referred to as a-Si) photoconductor. The a-Si photoconductor has durability such as heat resistance and friction resistance, a wide sensitivity range, and high sensitivity. Therefore, various laser beams can be used, and copying machines and the like can be made faster and more multifunctional. Can be achieved. However, although the a-Si photoreceptor has such advantages, it is generally difficult to increase the film thickness from the viewpoint of cost and mass productivity, and a practical a-Si photoreceptor cannot increase the charging ability. Therefore, it is necessary to use a toner that can be developed with a low potential contrast, and it is important to increase the charge amount of the toner and to control it as uniformly as possible. In particular, it is important to prevent a decrease in toner charge amount and a decrease in toner fluidity in a high temperature and high humidity environment.

  Moreover, although the a-Si photosensitive member has high surface hardness and high durability, there is a problem that the surface of the photosensitive member is difficult to be scraped. In the electrophotographic process, the toner developed on the photoconductor is transferred to a transfer material such as paper, but the toner remaining on the photoconductor without being transferred at that time is removed by a cleaning process. Therefore, the toner that could not be completely removed is not a problem because it is usually scraped together with the surface of the photoreceptor by friction with the toner in the subsequent development and transfer processes. However, since the a-Si photosensitive member has a high hardness, the surface is difficult to be scraped, and it is difficult to remove the residual toner, thereby easily causing toner fusion to the photosensitive member.

  In addition, impurities such as paper dust, ozone deposits, or exudates from the conveyance rubber roller attached to the photoreceptor via the transfer material are present on the surface of the photoreceptor. Impurities are not scraped together with the surface of the photoconductor as in the case of residual toner. Similarly, in the a-Si photoconductor, it is difficult to remove the impurities, and image defects such as image flow are likely to occur.

  In recent years, output devices using such an image forming method have been strictly pursued to be smaller, lighter, faster, higher in image quality, and higher in reliability. On the other hand, the application fields of these output devices are expanding from the personal use to the professional use, and in particular, full-fledged as light printing (print-on-demand capable of high-mix low-volume printing; POD). Therefore, the performance required for image forming systems and toners has become higher.

Assuming light printing applications, the performance that is required to be improved from the prior art is particularly high-quality print images, high-speed printability, high reliability, and high durability. It is necessary to cope with a wide variety of transfer materials that are generally used.
The issues to be overcome in order to cope with a wide variety of transfer materials are to maintain stable transportability for transfer materials having various characteristics (for example, material, thickness, size) and to sensitize them without excess or deficiency. The toner image on the body is transferred onto a transfer material.

  As a transfer means, a type using corona discharge is widely used because of its relatively simple structure. However, the transfer means using corona discharge has a narrow transfer material adsorbing area to the photosensitive member, which is a toner image carrier, and lacks a stable sense of transportability. In some cases, satisfactory results could not be obtained in terms of quality. Furthermore, when used in the reversal development method, the transfer material and the photoconductor are charged with opposite polarities, so when charged with a strong electric field, the transfer material and the photoconductor are electrostatically adsorbed and the transfer process is completed. It cannot be separated later, and it is easy to cause a “wrapping” phenomenon in which the transfer material enters the next process and causes a paper jam. As a countermeasure against this, it has been proposed to eliminate the charge on the transfer material by using a static elimination needle or a static elimination brush, but it is still insufficient.

For the purpose of these improvements, various proposals have been made to include an inorganic fine powder as an abrasive, a lubricant, and a separation aid in the toner. For example, Patent Document 1 discloses using cerium oxide particles as abrasive particles. However, in such a method, it is difficult to obtain a stable image density in digital high-speed development or low-potential development, and particularly when positively charged toner is used, a decrease in chargeability is observed. In Patent Document 2, Patent Document 3 and Patent Document 4, the photosensitive member is polished by containing an inorganic fine powder such as strontium titanate to remove deposits such as toner fusion and paper dust on the photosensitive member. It is disclosed. These fine powders alone have some effect on the abrasiveness to the photoreceptor, but no effect on the separation of the transfer material. Similarly, Patent Documents 5 and 6 disclose a method of adding strontium titanate fine particles having a number average particle diameter of 80 to 800 nm to a toner as a cleaning aid. However, these fine particles have a weak polishing power and have insufficient removal of impurities on the surface of the photoreceptor for an amorphous silicon photoreceptor having a high hardness surface. On the other hand, Patent Document 7 proposes using silica fine powder and resin particles as a separation aid. However, in high-speed and long-term use, the particles are embedded in the toner, and the effect becomes insufficient.
Japanese Patent Publication No. 06-12461 Japanese Patent Laid-Open No. 2-110475 Japanese Patent Publication No.2-110475 JP 2004-126263 A Japanese Patent No. 3047900 Japanese Patent No. 3385860 Japanese Patent No. 2568244

An object of the present invention is to provide an image forming method that solves the above-described problems.
That is, an object of the present invention is to provide an electrostatic latent image on a photoreceptor comprising a conductive substrate, a photoconductive layer containing at least amorphous silicon, and a surface protective layer containing amorphous silicon and / or amorphous carbon on the conductive substrate. In an image forming method for developing a toner by a reversal development method, an image forming method capable of obtaining a stable image density without causing image flow and toner fusion is provided. A further object of the present invention is to provide an image forming method that is excellent in transferability, excellent in separation between a transfer material and a photoreceptor, and does not cause paper jam such as winding.

The invention according to the present application for achieving the above-described object is as follows.
(1) A charging process for charging the surface of the photoreceptor, a latent image forming process for forming an electrostatic latent image on the photoreceptor by exposure, and a toner image is formed by developing the electrostatic latent image with toner by a reversal development method. A developing process, a transfer process in which the toner image is electrostatically transferred to a transfer material, a separation process in which the transfer material and the photosensitive member are separated, and a transfer residual toner remaining on the photosensitive member after the transfer process is applied to the photosensitive member by a cleaning member. In the image forming method having a cleaning step of removing from
The photoreceptor is provided with a conductive substrate, a photoconductive layer containing at least amorphous silicon and a surface protective layer containing amorphous silicon and / or amorphous carbon on the conductive substrate,
The toner has toner particles containing at least a binder resin and a colorant, at least the particle shape is cubic or rectangular parallelepiped perovskite type crystal and is the number average particle size of less than 300nm or 80nm inorganic fine powder A and, Compound containing inorganic fine powder B having a number average particle diameter of 300 nm or more and less than 3000 nm, wherein both inorganic fine powder A and inorganic fine powder B are selected from the group consisting of strontium titanate, barium titanate and calcium titanate. An image forming method characterized by the above.
(2) The transfer step is a step in which the photosensitive member is brought into contact with a transfer material conveyed by an endless transfer conveyance unit and transferred, and the endless transfer conveyance unit is a transfer belt, and the transfer belt Is supported by at least two or more rollers installed upstream and downstream in the conveyance direction of the portion in contact with the photosensitive member, and the transfer belt enters the surface of the photosensitive member at the contact portion with the photosensitive member. The image forming method as described in (1) , wherein the amount i is in the range of more than 0% and 5% or less of the photoreceptor diameter d.
( 3 ) The binder resin is selected from the group consisting of a vinyl resin having a carboxyl group and a vinyl resin having an epoxy group, a vinyl resin having a carboxyl group and an epoxy group, and a vinyl resin in which a carboxyl group and an epoxy group are reacted. (1) or (2 ), wherein the toner has an acid value of 1 to 50 mg KOH / g.
( 4 ) When the content (mass%) of the inorganic fine powder A in the toner is Aβ and the content (mass%) of the inorganic fine powder B is Bβ, Aβ / Bβ is 0.1 or more and 3. The image forming method according to any one of (1) to ( 3 ), wherein the image forming method is less than 5.

  According to the image forming method of the present invention, even in an electrophotographic apparatus using a reversal development method using an amorphous silicon photoreceptor, there is no occurrence of conveyance failure due to transfer separation failure, and image flow, toner fusion, poor cleaning, etc. occur. Therefore, toner charging stability is excellent, and development stability and durability can be obtained.

The contents of the present invention will be described in more detail. In the present invention, a charging process for charging the surface of the photoreceptor, a latent image forming process for forming an electrostatic latent image on the photoreceptor by exposure, and developing the electrostatic latent image with toner by a reversal development method to form a toner image. The developing process to be formed, the transfer process for electrostatically transferring the toner image to the transfer material, the separation process for separating the transfer material from the photoconductor, and the transfer residual toner remaining on the photoconductor after the transfer process on the photoconductor In a method of forming an image having a cleaning step for removing the toner, a specific photoconductor and a specific toner are used. First, the photoconductor used in the present invention will be described.

  The photoreceptor used in the present invention comprises a conductive substrate, a photoconductive layer containing at least amorphous silicon, and a surface protective layer containing amorphous silicon and / or amorphous carbon on the conductive substrate. To do.

FIG. 2 shows a partial cross-sectional view of an example of the photoreceptor used in the present invention.
As the conductive substrate 21 shown in FIG. 2, for example, aluminum (Al) is the most common, but chromium (Cr), molybdenum (Mo), gold (Au), indium (In), niobium (Nb), It is possible to use metals such as tellurium (Te), vanadium (V), titanium (Ti), platinum (Pt), lead (Pd), iron (Fe), and alloys thereof such as stainless steel. In addition, a transparent substrate such as glass or plastic, or an insulator such as ceramic is also made into a conductive substrate by conducting a conductive treatment on its surface, that is, the surface on the side where the photoconductive layer 23 is formed. Can do.

  Further, the photoreceptor used in the present invention includes at least a photoconductive layer 22 containing amorphous silicon on the conductive substrate 21 and a surface protective layer 23 containing amorphous silicon and / or amorphous carbon on the photoconductive layer 22.

  The photoconductive layer 22 may be organic or inorganic as long as it has photoconductivity. However, as the inorganic photoconductive layer, for example, an amorphous film in which silicon atoms contain hydrogen atoms and / or halogen atoms is used. It is preferable to use a quality material (hereinafter abbreviated as a-Si (H, X)) as a main component. Or inorganic materials, such as a-Se, can be combined suitably.

Moreover, it is preferable that the photoconductive layer 22 contains an atom for controlling conductivity as required.
The atoms that control conductivity may be uniformly distributed in the photoconductive layer 22 or may be unevenly distributed. Examples of the atoms that control conductivity include so-called impurities in the semiconductor field, atoms belonging to Group III of the periodic table that give p-type conduction characteristics (hereinafter abbreviated as “Group III atoms”), or n-type conduction. An atom belonging to Group V of the periodic table giving characteristics (hereinafter abbreviated as “Group V atom”) can be used.
Specific examples of the group III atom include boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl). In particular, boron (B), aluminum (Al), and gallium. (Ga) is preferred.
Specific examples of the group V atom include phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi), and phosphorus (P) and arsenic (As) are particularly preferable. By appropriately doping these impurities, the charging polarity of the amorphous photoreceptor can be determined.

  Further, in order to improve the photosensitive characteristics, the photoconductive layer 22 may have a plurality of layers such as a lower photoconductive layer 25 and an upper photoconductive layer 26. Although there is no limitation in particular as the film thickness of the photoconductive layer 22, about 15-50 micrometers is suitable from relationships, such as manufacturing cost.

  The surface protective layer 23 is generally a non-single-crystal (preferably amorphous) material (a-SiC (H, H) containing a silicon atom as a base and containing a carbon atom and, if necessary, a hydrogen atom and / or a halogen atom. X)), a non-single crystal (preferably amorphous) material having a silicon atom as a base and containing a nitrogen atom and optionally a hydrogen atom and / or a halogen atom, (a-SiN (H, X)), Alternatively, a non-single-crystal carbon (preferably amorphous carbon) (a-C (H, X)) containing a hydrogen atom and / or a halogen atom as a base is used as necessary.

In particular, a-C (H, X) is preferable for the purpose of improving the contact property with the transfer belt, and in the present invention, the effect of improving transfer dropout is more easily manifested.
Although there is no limitation in particular as the film thickness of the surface protective layer 23, about 0.05-2 micrometers is suitable from a viewpoint that what is necessary is just to exist at the minimum necessary for actual use. In addition, it is preferable to provide an interface layer (or antireflection layer) 27 in which the interface composition between the photoconductive layer 22 and the surface protective layer 23 is continuously changed, and to control the interface reflection in this portion.
In addition, the surface of the conductive substrate 21 is preferably formed into a concavo-convex groove or dimple shape by cutting or the like. By adopting such a surface shape, it is possible to make it difficult to see the interference fringes caused by the reflection of the exposure light that has reached the surface of the conductive substrate 21, and the substrate of the film formed on the conductive substrate 21. The adhesion with 21 is also improved. Further, the shape of the conductive substrate may be as desired according to the driving method of the photosensitive member.

  Of course, in addition to these layers, various functional layers such as the charge injection blocking layer 24 as shown may be provided as necessary. For example, by providing the charge injection blocking layer 24 and appropriately selecting the dopant from group III atoms, group V atoms, etc., charge polarity control such as positive charge or negative charge becomes possible.

Next, the toner used in the present invention will be described.
The toner used in the present invention includes an inorganic fine powder A having a number average particle diameter of at least 80 nm and less than 300 nm of toner particles containing at least a binder resin and a colorant and at least a perovskite crystal having a cubic or rectangular parallelepiped shape. And inorganic fine powder B having a number average particle size of 300 nm or more and less than 3000 nm.

By containing these two kinds of inorganic fine powders, the toner transferability is excellent even during high-speed printing, and the occurrence of poor separation such as winding is prevented. Furthermore, the occurrence of image flow or the like can be prevented and high durability can be achieved.
That is, since the inorganic fine powder A has a cubic or rectangular parallelepiped shape, the inorganic fine powder A is easily fixed on the toner surface and is less likely to be detached from the toner surface or embedded in the toner as compared with the spherical particles, and tends to remain on the toner surface. Further, since the inorganic fine powder A is present on the toner surface, embedding of the inorganic fine powder B and other fluidity imparting agents due to the friction between the toners is difficult to occur, preventing toner deterioration and the inorganic fine powder B. The effect can be demonstrated over a long period of time.
Further, in the transfer step, the inorganic fine powder A exists on the toner surface and functions as a spacer between the photosensitive member and the toner, so that the releasability of the toner is improved and the transfer efficiency is improved.

  When the number average particle diameter of the inorganic fine powder A is less than 80 nm, the release effect of the inorganic fine powder A is difficult to be expressed, and since the fine powder is fine, the inorganic fine powder A is embedded in the toner. It cannot be suppressed from being embedded in the toner. Further, when the number average particle diameter of the inorganic fine powder A is 300 nm or more, it becomes difficult to adhere to the toner surface and is detached, and similarly, the effect of suppressing the embedding of the inorganic fine powder B is difficult to be exhibited.

  In the inorganic fine powder B, the inorganic fine powder A is fixed on the surface of the toner to prevent embedding, so that it exists on the outermost surface of the toner. The detachment component easily retains the opposite polarity to the toner due to friction with the toner, and is developed in the non-image portion in the development process. The inorganic fine powder B developed in the non-image area serves as a spacer between the transfer material and the photoconductor during the separation process, and can suppress electrostatic adsorption between the transfer material and the photoconductor to prevent wrapping. Become. When the number average particle diameter of the inorganic fine powder B is less than 300 nm, the spacer effect is difficult to be exhibited and poor separation occurs.

Further, the inorganic fine powder B developed on the non-image portion remains on the photoreceptor after the transfer process and is collected in the cleaning process. In the cleaning process, the inorganic fine powder B is selectively accumulated at the contact portion between the cleaning member and the photosensitive member, and a blocking layer that blocks the leakage of toner from the cleaning member can be formed to prevent toner slippage.
When the number average particle diameter of the inorganic fine powder B is 3000 nm or more, the photosensitive member is damaged in a streak shape, causing streaking.

Further, when the number average particle diameters of the inorganic fine powders A and B used in the present invention are Aα and Bα, Aα / Bα is preferably in the range represented by the following formula 1.
(Formula 1) 0.05 ≦ Aα / Bα ≦ 0.8

When Aα / Bα is less than 0.05, since the inorganic fine powder A is extremely smaller than the inorganic fine powder B, the effect of suppressing the embedding of the inorganic fine powder A tends to be small. As a result, during long-term use, the inorganic fine powder B is gradually embedded in the toner, which may cause separation failure, cleaning failure, toner fusion, and the like. Further, when Aα / Bα is 0.8 or more, there is no difference in the particle diameter between the inorganic fine powder A and the inorganic fine powder B, and the inorganic fine powder A tends to be difficult to selectively adhere to the toner surface. . For this reason, the inorganic fine powder A may be detached from the toner and the reverse fogging may be deteriorated.

The number average particle diameter of the inorganic fine powder in the present invention was determined by measuring 100 particle diameters from a photograph taken with an electron microscope at a magnification of 50,000 times, and taking the average value. The particle size was determined as (a + b) / 2, where a is the longest side of the primary particles and b is the shortest side.
In order to confirm that the crystal structure of the inorganic fine powder is a perovskite type (a face-centered cubic lattice composed of three different elements), it can be confirmed by performing X-ray diffraction measurement.

Furthermore, the total content of the inorganic fine powders A and B in the toner is preferably 1.0% by mass or more and 6.0% by mass or less, and the content (% by mass) of A is the content of Aβ and B. When (mass%) is Bβ, Aβ / Bβ is preferably 0.1 or more and less than 3.5. Aβ + Bβ is 1
. If it is less than 0% by mass, there is little interposition on the surface of the toner particles, and it is difficult to show the effect of embedding a fluidity improver or the like, and the effect on image flow is also reduced. When the inorganic fine powder A passes through the blade more frequently, the charging member tends to be contaminated. If Aβ / Bβ is less than 0.1, the effect of the inorganic fine powder B is reduced, the effect of reducing the adhesion of the charging member is reduced, and if it is 3.5 or more, the inorganic fine powder A slips through more. This is not preferable because the intervening effect of the inorganic fine powder B on the surface of the charging member is also reduced.

  The inorganic fine powders A and B used in the present invention are preferably at least one oxide selected from strontium titanate, barium titanate, and calcium titanate. By using the above, particularly when a positively chargeable toner is used, charging inhibition of the toner is difficult to occur, and the inorganic fine powder easily exhibits a role as a separation aid between the photoreceptor and the transfer material. In particular, strontium titanate easily exhibits the above effect

In the present invention, the electrostatic adsorption mitigating action of the transfer material and the photoreceptor is manifested when the toner used in the present invention contains inorganic fine powder, but is not proportional to the content of the inorganic fine powder. Accordingly, the content of the inorganic fine powder is preferably 0.01 to 10.0 parts by mass with respect to 100 parts by mass of the toner particles. This is because an excellent separability assisting effect is easily exhibited within the above range.
When the amount exceeds 10.0 parts by mass, the inorganic fine powder may cause image defects such as fogging, and when the amount is less than 0.01 parts by mass, the effect as a separation aid decreases.

Further, the inorganic fine powders A and B used in the present invention may be used after surface treatment with a known surface treatment agent. In this case, it is preferable to use a fatty acid or a fatty acid metal salt as the surface treating agent from the viewpoint of improving the hygroscopicity of the inorganic fine powder.
The number of carbon atoms of the fatty acid or metal salt thereof used as the surface treatment agent is preferably 10 to 35. When the number of carbons exceeds 35, the adhesion between the surface of the inorganic fine powder A and the fatty acid or metal salt thereof is reduced, and the surface is peeled off from the surface of the inorganic fine powder due to long-term use. Fatty acids or fatty acid metal salts are not preferred because they cause fogging. Moreover, when the number of carbon atoms of the fatty acid or fatty acid metal salt is less than 8, it is not preferable because the effect of improving hygroscopicity is lowered.
The amount of the surface treatment agent used is 0.1 to 15.0 mass%, more preferably 0.5 to 12.0 mass%, based on the inorganic fine powder matrix.

  The binder resin contained in the toner particles of the present invention includes a vinyl resin having a carboxyl group and a vinyl resin having an epoxy group, a vinyl resin having a carboxyl group and an epoxy group, and a vinyl resin in which the carboxyl group and the epoxy group are reacted It is preferable to contain at least one vinyl resin selected from the group consisting of: By having the above configuration, the resin is melted and kneaded in the kneading step in the toner manufacturing process and the binder resin is subjected to a crosslinking reaction. In this case, the carboxyl group unit and the epoxy group unit in the binder resin are subjected to a crosslinking reaction. In the above, by including other materials, the affinity between the binder resin and the other materials is increased, and good dispersibility can be achieved in the toner particles. Further, the detachment of the inorganic fine powder from the binder resin can be suppressed, and as a result, the separation property, transfer property, and cleaning property can be improved.

  Furthermore, the toner of the present invention can make the toner itself tough by performing the crosslinking reaction as described above, and can be stably used even when the copy volume increases, such as when applied to a high-speed machine. Sex can be achieved.

The following are mentioned as a monomer which has the carboxyl group which comprises the vinyl resin which has the said carboxyl group.
Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, cinnamic acid, vinyl acetic acid, isocrotonic acid, tiglic acid and angelic acid, anhydrides thereof and α -Or β-alkyl derivatives, fumaric acid, maleic acid, citraconic acid, alkenyl succinic acid, itaconic acid, mesaconic acid, dimethyl maleic acid, dimethyl fumaric acid and other unsaturated dicarboxylic acids, monoester derivatives, anhydrides and α- Alternatively, β-alkyl derivatives and the like can be mentioned.
A monomer having a carboxyl group can be obtained by copolymerizing such a monomer having a carboxyl group alone or in combination with another vinyl monomer by a known polymerization method.

  The acid value of the vinyl resin having a carboxyl group is preferably 0.5 to 60 mgKOH / g. When the amount is less than 0.5 mg KOH / g, the number of cross-linking reaction sites between the carboxyl group and the epoxy group is decreased, so that the cross-linking component is small and the durability of the toner is hardly exhibited. Compensation can be made to some extent by using a vinyl resin having a high-valent epoxy group. When it exceeds 60 mgKOH / g, when applied to a positively chargeable toner, the negative chargeability of the binder resin in the toner particles becomes strong, the image density tends to decrease, and the fog tends to increase.

The glass transition temperature (Tg) of the vinyl resin having a carboxyl group is preferably 40 to 70 ° C. When the Tg is less than 40 ° C., the blocking resistance of the toner is deteriorated, and when it exceeds 70 ° C., the fixability of the toner is deteriorated. The glass transition temperature (Tg) of, for example, shows Sahashi査熱meter: can be measured using the (M-DSC TA- Instruments Inc.). As a measurement sample, 6 mg is precisely weighed and used. A precisely weighed measurement sample is put in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a temperature rise rate of 4 ° C./min at room temperature and normal humidity within a measurement temperature range of 20 ° C. to 200 ° C. At this time, the measurement is performed with a modulation amplitude of ± 0.6 ° C. and a frequency of 1 / min. Then, the glass transition temperature (Tg) is calculated from the obtained reversing heat flow curve. In the calculation, the midpoint of the straight line connecting the intersection of the tangent lines of the baseline and the endothermic curve is obtained, and this is defined as the glass transition temperature (Tg).

  In the vinyl resin having a carboxyl group, the number average molecular weight (Mn) is preferably 1,000 to 40,000 in order to achieve good fixability and developability, and the weight average molecular weight is good offset resistance. In order to achieve blocking resistance and durability, 10,000 to 10,000,000 is preferable.

  The vinyl resin having a carboxyl group is desirably composed of a low molecular weight component and a high molecular weight component. The peak molecular weight of the low molecular weight component is preferably 4,000 to 30,000 in order to achieve good fixability, and the peak molecular weight of the high molecular weight component achieves good offset resistance, blocking resistance and durability. Therefore, 100,000 to 1,000,000 is preferable.

  The epoxy group in the vinyl resin having an epoxy group is a functional group in which an oxygen atom is bonded to two atoms of carbon in the same molecule, and has a cyclic ether structure. Typical cyclic ether structures include a 3-membered ring, a 4-membered ring, a 5-membered ring, and a 6-membered ring. Among them, a 3-membered ring structure is preferable.

The following are mentioned as a monomer which has the epoxy group unit which comprises the vinyl resin which has the said epoxy group.
Examples include glycidyl acrylate, glycidyl methacrylate, β-methyl glycidyl acrylate, β-methyl glycidyl methacrylate, allyl glycidyl ether, and allyl β-methyl glycidyl ether. Moreover, the glycidyl monomer represented by General formula (1) is used preferably.

(In the general formula (1), R1, R2 and R3 represent hydrogen, an alkyl group, an aryl group, an aralkyl group, a carboxyl group and an alkoxycarbonyl group.)

  Such a monomer having an epoxy group unit can be obtained alone or in combination and copolymerized with a vinyl monomer by a known polymerization method to obtain a vinyl resin having the epoxy group.

The vinyl resin having an epoxy group has a weight average molecular weight (Mw) of preferably 2,000 to 100,000, more preferably 2,000 to 50,000, and still more preferably 3,000 to 40,000. That is good. When the weight average molecular weight (Mw) is less than 2,000, the molecular weight increases due to the cross-linking reaction in the binder resin, resulting in many molecular breaks due to the kneading step, which deteriorates durability. When the weight average molecular weight (Mw) exceeds 100,000, the fixability is affected.

  The epoxy value is preferably 0.05 to 5.0 eq / kg. When the amount is less than 0.05 eq / kg, the crosslinking reaction does not easily proceed, the amount of high molecular weight components and THF-insoluble components generated decreases, and the toughness of the toner decreases. If it exceeds 5.0 eq / kg, the cross-linking reaction is likely to occur, but in the kneading process, there are many molecular breaks and the dispersibility with other materials deteriorates.

  Further, when the epoxy value is in the above range, it is possible to uniformly disperse the epoxy group in the toner, thereby appropriately increasing and controlling the dielectric loss of the toner. By using the elastic blade together with the elastic blade as in the present invention, the toner can be uniformly charged regardless of the environmental temperature change.

  The vinyl resin having an epoxy group has a mixing ratio of 0.01 to 10.0 equivalents, preferably 0.03 to 5.0 equivalents of epoxy groups with respect to 1 equivalent of carboxyl groups in the carboxyl group-containing vinyl resin. It is preferable to be used.

  When the said epoxy group is less than 0.01 equivalent, in a binder resin, a crosslinking point will decrease and the effect by crosslinking reactions, such as durability, will become difficult to express. On the other hand, if the epoxy group exceeds 10 equivalents, the crosslinking reaction tends to occur, but the generation of excess THF-insoluble matter causes deterioration of dispersibility, resulting in deterioration of grindability and development stability. Come out.

  In the vinyl resin having a carboxyl group and an epoxy group, the number average molecular weight (Mn) is preferably 10,000 to 40,000 in order to achieve good developability and durability. The weight average molecular weight (Mw) is preferably 10,000 to 10,000,000 in order to achieve offset resistance, blocking resistance and durability.

  The vinyl resin having a carboxyl group and an epoxy group can be obtained by mixing a monomer having a carboxyl group unit and a monomer having an epoxy group unit and copolymerizing it with another vinyl monomer by a known polymerization method.

Moreover, in this invention, you may use what reacted beforehand the vinyl resin which has a carboxyl group, and the vinyl resin which has an epoxy group at the time of resin manufacture.
As a reaction means, (1) a vinyl resin having a carboxyl group and a vinyl resin having an epoxy group are mixed in a solution state, and a crosslinking reaction is caused by applying heat in a reaction kettle, and (2) a carboxyl group. Take out the vinyl resin having epoxy and the vinyl resin having epoxy group from the reaction kettle, dry blend with a Henschel mixer, etc., and heat melt knead with a biaxial extruder etc. May be.

When the vinyl resin having a carboxyl group and a resin having an epoxy group reacted is used, it is preferable to contain 0.1 to 60% by mass of THF-insoluble matter. When the THF-insoluble content is in the above range, the resin itself can have an appropriate melt viscosity in the kneading step in the production process, so that uniform dispersibility of the material can be achieved.
On the other hand, when the THF-insoluble content exceeds 60% by mass, the melt viscosity of the resin itself is increased and the dispersibility of the material is deteriorated.

Examples of the vinyl monomer copolymerized with the monomer having a carboxyl group unit and the monomer having an epoxy group unit include the following.
As monomers other than the monomer having a carboxyl group unit and the monomer having an epoxy group unit, for example, styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene. ,
3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, p- Styrene derivatives such as n-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methyl methacrylate, ethyl methacrylate, methacrylic acid Propyl, n-butyl methacrylate, isobuty methacrylate , Α-methylene aliphatic monocarboxylic esters such as n-octyl methacrylate, dodecyl methacrylate, methacrylic acid (2-ethylhexyl), stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate Methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, 1-octyl acrylate, dodecyl acrylate, acrylic acid (2-ethylhexyl), stearyl acrylate, acrylic acid (2 -Chlorethyl), acrylic esters such as phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone Vinyl ketones such as methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthalenes; acrylonitrile, methacrylonitrile, acrylamide And acrylic acid derivatives or methacrylic acid derivatives. These vinyl monomers are used alone or in admixture of two or more monomers.

  Among these, a combination of monomers that becomes a styrene copolymer and a styrene-acrylic copolymer is preferable. In this case, at least 65% by mass or more of the styrene copolymer component or the styrene-acrylic copolymer component is used. It is preferable to contain it from the viewpoint of fixing property and mixing property.

In addition, as the binder resin used in the toner particles of the present invention, the following polymers can be added.
For example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and substituted products thereof; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-pinylnaphthalene copolymer Polymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene- Styrene copolymers such as vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer; polyvinyl chloride, Phenolic resin, natural modification Enol resin, natural resin-modified maleic resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin Petroleum resin can be used.

The toner used in the present invention preferably has an acid value of 1 to 50 mgKOH / g in THF-soluble matter. By controlling the acid value of the toner within this range, for example, the affinity between the carboxyl group on the toner particle surface and the surface of the inorganic fine powder is improved, and the inorganic fine powder can be reliably present on the toner particle surface. In addition, it is possible to suppress excessive detachment of the inorganic fine powder and achieve both transferability / separability / cleanability.

When the acid value of the toner is less than 1 mgKOH / g, the affinity between the toner particle surface and the inorganic fine powder is decreased, so that the inorganic fine powder is easily detached from the toner particle surface. As a result, the effect of improving the transferability of the inorganic fine powder A and the effect of suppressing the embedding of the inorganic fine powder in the toner tend to be difficult to obtain. When the acid value exceeds 50 mgKOH / g, the affinity between the toner particle surface and the inorganic fine powder becomes so large that the effect of assisting the separation of the inorganic fine powder B and the effect as a cleaning aid are difficult to be exhibited. Further, when the acid value exceeds 50 mgKOH / g, for example, when applied to a positively chargeable toner, the negative chargeability of the binder resin in the toner particles becomes strong, and the toner chargeability tends to be inhibited.

  In the present invention, the acid value of the toner or binder resin can be determined as follows. The basic measurement operation is in accordance with JIS K-0070.

1) A sample 0.5 to 2.0 (g) is precisely weighed to obtain a sample weight W (g).
2) A sample is put into a 300 (ml) beaker, and a mixed solution 150 (ml) of toluene / ethanol (4/1) is added and dissolved.
3) Titrate using 0.1N KOH methanol solution with potentiometric titrator <For example, potentiometric titrator AT-400 (win workstation) and AB manufactured by Kyoto Electronics Co., Ltd.
Automatic titration using a P-410 electric burette can be used. >
At this time, the usage amount of the KOH solution is S (ml), and at the same time, a blank is measured, and the usage amount of the KOH solution at this time is B (ml).
4) The acid value is calculated by the following formula 2. f is a factor of KOH.
(Formula 2) Acid value (mgKOH / g) = ((SB) × f × 5.61) / W

  The number average molecular weight (Mn) of the THF soluble content of the toner used in the present invention measured by gel permeation chromatography (GPC) is preferably 1,000 to 40,000, and more preferably 2, 000 to 20,000, particularly preferably 3,000 to 15,000. On the other hand, the weight average molecular weight (Mw) of the THF soluble content of the toner used in the present invention measured by gel permeation chromatography (GPC) is preferably 10,000 to 10,000,000, and more preferably. It is 20,000 to 5,000,000, particularly preferably 30,000 to 1,000,000.

  When the toner used in the present invention exhibits the above average molecular weight in GPC having a THF soluble content, it becomes possible for the toner to maintain an appropriate charge amount and toughness, and the share of the toner in the developing unit is increased. Even in a high-speed and high-durability system having a large size, good developability and durability can be achieved, and toner fusion can be prevented from occurring.

  When the number average molecular weight (Mn) is less than 1,000 or when the weight average molecular weight (Mw) is less than 10,000, the melt viscosity of the toner is lowered, resulting in a non-uniform charge distribution, fog suppression, etc. Is easy to worsen. On the other hand, when the number average molecular weight (Mn) exceeds 40,000 or the weight average molecular weight (Mw) exceeds 10,000,000, the phase between the high molecular component and the low molecular component in the binder resin The solubility deteriorates, the component distribution of the binder resin itself becomes non-uniform, the material dispersibility in the toner deteriorates, and the dot reproducibility deteriorates.

  Further, in the molecular weight distribution of the THF soluble content of the toner used in the present invention measured by GPC, a toner having a main peak in the molecular weight region of 4,000 to 30,000 is preferable, and the molecular weight is 5,000 to 20,000. Those having a main peak in the region are more preferred.

When the main peak has a molecular weight of less than 4,000, sleeve fusion or the like is likely to occur in a high temperature environment. When the main peak exceeds 30,000, the material dispersibility is deteriorated and the dot reproducibility is deteriorated.

  In the molecular weight distribution, the peak area with a molecular weight of 30,000 or less is preferably 60 to 100% of the total peak area. When the peak area with a molecular weight of 30,000 or less is within the above range, good material dispersibility can be achieved in the toner particles. When the peak area is less than 60%, the melt viscosity of the resin increases, and the melting during toner production Uniform dispersion with other materials becomes difficult during kneading.

  Further, the resin component in the toner used in the present invention preferably contains 0.1 to 60% by mass of THF-insoluble matter. It is more preferable to contain 5 to 60% by mass of THF-insoluble matter, and it is particularly preferable to contain 10 to 45% by mass. When the THF-insoluble content is within the above range, uniform dispersibility of the material can be achieved in the toner particles, and the toner itself can have appropriate toughness, so that good developability and durability can be achieved. .

  When the THF-insoluble content exceeds 60% by mass, the melt viscosity of the resin increases, and the dispersion state of the material is deteriorated in the toner particles, resulting in non-uniform charging. The charge distribution becomes uneven and the dot reproducibility deteriorates.

  In the present invention, the molecular weight distribution of the THF-soluble component of the binder resin component in the toner and the THF-soluble component of the raw material binder resin can be measured as follows.

<Measurement of molecular weight distribution by GPC>
The column is stabilized in a heat chamber at 40 ° C., and THF as a solvent is allowed to flow through the column at this temperature at a flow rate of 1 ml per minute, and about 100 μl of the THF sample solution is injected and measured. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count value. As a standard polystyrene sample for preparing a calibration curve, for example, a product having a molecular weight of about 10 ² to 10 ⁷ manufactured by Tosoh Corporation or Showa Denko is used, and at least about 10 standard polystyrene samples are suitably used. . An RI (refractive index) detector is used as the detector. Note that in a column, may to combine a plurality of commercially available polystyrene gel columns, or a combination of shodex GPC KF-801,802,803,804,805,806,807,800P for example, manufactured by Showa Denko KK, Examples include TSKgel G1000H (HXL), G2000H (HXL), G3000H (HXL), G4000H (HXL), G5000H (HXL), G6000H (HXL), G7000H (HXL), and TSKgold column manufactured by Tosoh Corporation.

The sample is prepared as follows.
Place the sample in THF, leave it for several hours, then shake well and mix well with THF (until the sample is no longer united) and let stand for more than 12 hours. At that time, the standing time in THF should be 24 hours or more. Thereafter, a sample processed filter (pore size 0.2 to 0.5 μm, for example, Mysori Disc H-25-2 (manufactured by Tosoh Corporation) can be used) is used as a GPC sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

  In the present invention, the THF-insoluble content of the binder resin component in the toner and the THF-insoluble content of the raw material binder resin are measured as follows.

<Measurement of THF-insoluble matter>
1.0-2.0 g of toner is weighed (W1 g), cylindrical filter paper (for example, No. 86R manufactured by Toyo Roshi Kaisha Co., Ltd.) is put into a Soxhlet extractor, extracted with 200 ml of THF as a solvent, and extracted for 10 hours. After evaporating the soluble component solution obtained, it is vacuum dried at 100 ° C. for several hours, and the amount of the THF soluble resin component is weighed (W2 g). The weight of the incineration residual ash in the toner is determined (W3 g).
The incineration residual ash content is obtained by the following procedure. About 2.0 g of a sample is placed in a 30 ml magnetic crucible that has been precisely weighed in advance, and weighed accurately, and the mass (Wa) g of the sample is precisely weighed. The crucible is put in an electric furnace, heated at about 900 ° C. for about 3 hours, allowed to cool in the electric furnace, allowed to cool in a desiccator for 1 hour or more at room temperature, and the mass of the crucible is precisely weighed. From this, incineration residual ash content (Wb) g is obtained.
(Wb / Wa) × 100 = Incineration residual ash content (mass%)
The mass (W3g) of the incineration residual ash content in the sample is determined from this content rate.
The THF-insoluble content can be obtained from the following formula 3.
(Formula 3) THF insoluble matter = (W1- (W3 + W2)) / (W1-W3) × 100 (%)

Examples of a polymerization method that can be used in the present invention as a method for synthesizing the copolymer of the high molecular weight component include a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, and a suspension polymerization method.
Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is performed using a water-soluble polymerization initiator. In this method, the reaction heat can be easily adjusted, and since the phase in which the polymerization is carried out (oil phase consisting of a polymer and a monomer) and the aqueous phase are different, the termination reaction rate is low, and as a result, the polymerization concentration is low. Large and highly polymerized products are obtained. Furthermore, since the polymerization process is relatively simple and the polymerization product is fine particles, the toner can be easily mixed with colorants, charge control agents and other additives in the production of the toner. There is an advantage as a manufacturing method of the binder resin.
However, due to the added emulsifier, the polymer tends to become impure, and in order to remove the polymer, an operation such as salting out is necessary. To avoid this inconvenience, solution polymerization and suspension polymerization are convenient. is there.

  For example, the suspension polymerization may be performed with 100 parts by mass or less (preferably 10 to 90 parts by mass) of the monomer with respect to 100 parts by mass of the aqueous solvent. Examples of the dispersant that can be used include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like, and generally 0.05 to 1 part by mass with respect to 100 parts by mass of the aqueous solvent. The polymerization temperature is suitably 50 to 95 ° C., but is appropriately selected depending on the initiator used and the target polymer.

  In order to achieve the object of the present invention, the high molecular weight polymer of the resin composition used for the preparation of the resin may be used alone or in combination with a monofunctional polymerization initiator as exemplified below. It is preferable to produce them.

Specific examples of the polyfunctional polymerization initiator having a polyfunctional structure include 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,3-bis- (t-butylperoxy Isopropyl) benzene, 2,5-dimethyl-2,5- (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane, tris- (t-butyl) Peroxy) triazine, 1,1-di-t-butylperoxycyclohexane, 2,2-di-t-butylperoxybutane, 4,4-di-t-butylperoxyvaleric acid-n-butyl ester , Di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, di-t-butylperoxytrimethyladipate, 2,2-bis- ( , 4-di-t-butylperoxycyclohexyl) propane, 2,2-t-butylperoxyoctane and various polymer oxides, etc., a functional group having a polymerization initiating function such as two or more peroxide groups in one molecule. A polyfunctional polymerization initiator having the following: and a peroxide group in one molecule such as diallyl peroxydicarbonate, t-butylperoxymaleic acid, t-butylperoxyallylcarbonate and t-butylperoxyisopropyl fumarate And a polyfunctional polymerization initiator having both a functional group having a polymerization initiating function and a polymerizable unsaturated group.

  Of these, more preferred are 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-butylperoxycyclohexane, di-t-butylperoxy. Hexahydroterephthalate, di-t-butylperoxyazelate and 2,2-bis- (4,4-di-t-butylperoxycyclohexane) propane and t-butylperoxyallyl carbonate.

  These polyfunctional polymerization initiators are preferably used in combination with a monofunctional polymerization initiator in order to satisfy various performances required as a binder for toner. In particular, the polyfunctional polymerization initiator is preferably used in combination with a monofunctional polymerization initiator having a “10-hour half-life temperature” lower than the “10-hour half-life temperature” of the polyfunctional polymerization initiator.

  Specific examples of the monofunctional polymerization initiator include benzoyl peroxide, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-di (t- Organic peroxides such as butylperoxy) valerate, dicumyl peroxide, α-α'-bis (t-butylperoxydiisopropyl) benzene, t-butylperoxycumene, di-t-butylperoxide, azo Examples thereof include azo and diazo compounds such as bisisobutyronitrile and diazoaminoazobenzene.

These monofunctional polymerization initiators may be added to the monomer at the same time as the polyfunctional polymerization initiator, but in order to keep the efficiency of the polyfunctional polymerization initiator properly, in the polymerization process. It is preferably added after the half-life indicated by the polyfunctional polymerization initiator has elapsed.
These initiators are preferably used in an amount of 0.01 to 10 parts by mass with respect to 100 parts by mass of the monomer from the viewpoint of efficiency.

  A known method can be used as a method for synthesizing the low molecular weight component. However, in the bulk polymerization method, a polymer having a low molecular weight component can be obtained by polymerizing at a high temperature to increase the termination reaction rate, but there is a problem that the reaction is difficult to control. In that respect, in the solution polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in radical chain transfer caused by the solvent and adjusting the initiator amount and reaction temperature. It is preferable for obtaining a low molecular weight component in a vinyl resin having a carboxyl group.

As a solvent used in the solution polymerization, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol or benzene is used. When using a styrene monomer, xylene, toluene or cumene is preferred. The solvent is appropriately selected depending on the polymer to be polymerized. The reaction temperature varies depending on the solvent to be used, the polymerization initiator, and the polymer to be polymerized, but it is usually preferable to carry out at 70 to 230 ° C. In solution polymerization, it is preferable to carry out by 30-400 mass parts of monomers with respect to 100 mass parts of solvents.
Furthermore, it is also preferable to mix other polymers in the solution at the end of the polymerization, and several types of polymers can be mixed.

The toner particles used in the present invention preferably contain a magnetic material.
When the toner particles contain a magnetic material, the controllability of the surface resistance of the toner is improved, charge transfer between the toner particles and the inorganic fine powder is facilitated, and agglomeration between electrostatic toner particles is suppressed and transfer efficiency is reduced. Can be improved. In addition, the occurrence of transfer defects such as transfer misalignment can be suppressed.

Examples of the magnetic material include a metal oxide containing an element of iron, cobalt, nickel, copper, magnesium, manganese, aluminum, or silicon. Of these, those mainly composed of iron oxide such as triiron tetroxide and γ-iron oxide are preferred. From the viewpoint of toner chargeability control, other elements such as silicon element or aluminum element may be contained. These magnetic particles preferably have a BET specific surface area by nitrogen adsorption method of 2 to 30 m @ 2 / g, particularly 3 to 28 m @ 2 / g, and magnetic powder having a Mohs hardness of 5 to 7.

As the shape of the magnetic material, there are octahedron, hexahedron, sphere, needle shape, scale shape, etc., but the shape with less anisotropy such as octahedron, hexahedron, sphere, and indefinite shape increases the image density. Preferred above. The average particle size of the magnetic material is preferably 0.05 to 1.0 μm, more preferably 0.1 to 0.6 μm, and still more preferably 0.1 to 0.4 μm.
The content of the magnetic material is preferably 30 to 200 parts by weight, more preferably 40 to 200 parts by weight, and still more preferably 50 to 150 parts by weight with respect to 100 parts by weight of the binder resin. If the amount is less than 30 parts by weight, in a developing device that uses magnetic force for toner conveyance, the conveyance performance is insufficient, and the developer layer on the developer carrying member tends to become uneven, resulting in image unevenness, and further increase in developer tribo. The image density tends to decrease due to the above. When the content exceeded 200 parts by weight, there was a tendency for problems to occur in the fixing property.

  In the present invention, the toner particles can contain a charge control agent, whereby the positive chargeability or the negative chargeability can be maintained, and the chargeability can be controlled.

  The following substances are used for controlling the toner to be positively charged. For example, modified products such as nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and analogs of phosphonium salts thereof. Onium salts and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide) Metal salts of higher fatty acids; diorganotin oxides such as dibutyl tin oxide, dioctyl tin oxide, dicyclohexyl tin oxide; dibutyl tin borate, dioctyl tin borate, dicyclohexane Such diorgano tin borate such Rusuzuboreto; guanidine compounds, imidazole compounds. These can be used alone or in combination of two or more. In the present invention, among these, a triphenylmethane compound and a quaternary ammonium salt whose counter ion is not halogen are preferably used, and when these are used, generation of a reversal component of the toner is further suppressed. And transfer belt contamination can be reduced.

  Further, there are the following substances that control the toner to be negatively charged. For example, organometallic complexes and chelate compounds are effective, and there are monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acid metal complexes, and aromatic dicarboxylic acid metal complexes. Other examples of controlling the toner to be negatively charged include aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids and aromatic polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol. .

  As a method for incorporating the charge control agent into the toner, there are a method of adding it inside the toner particles and a method of adding it externally, and either method may be used. The amount of these charge control agents used is determined by the toner production method including the type of binder resin, the presence or absence of other additives, and the dispersion method, and is not uniquely determined. It is used in the range of 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the binder resin.

The toner particles used in the present invention contain a colorant.
The colorant includes any suitable pigment or dye. For example, examples of the pigment used as the colorant include carbon black, aniline black, acetylene black, naphthol yellow, Hansa yellow, rhodamine lake, alizarin lake, Bengala, phthalocyanine blue, and indanthrene blue. These are used in an amount necessary to maintain the optical density of the fixed image, and the amount added to the toner particles varies depending on the type of pigment, but is 0.1 to 20 parts by mass with respect to 100 parts by mass of the binder resin. Preferably it is 0.2-10 mass parts.

  Moreover, it is possible to use a dye for the same purpose. For example, dyes used as colorants include azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes, and the amount of addition varies depending on the type of the dye, but is 0.1. 1 to 20 parts by mass, preferably 0.3 to 10 parts by mass.

The toner used in the present invention preferably contains a wax in order to give releasability.
Examples of waxes used in the present invention include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; polyethylene oxide wax Oxides of aliphatic hydrocarbon waxes such as: block copolymers thereof; plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax; animal waxes such as beeswax, lanolin, whale wax Mineral waxes such as ozokerite, ceresin and petrolactam; waxes based on fatty acid esters such as montanic acid ester wax and castor wax; fatty acid esters such as deoxidized carnauba wax Those deoxidizing part or whole of the Le and the like.
Further, a saturated straight chain such as palmitic acid, stearic acid, montanic acid, or a long-chain alkyl carboxylic acid having a long-chain alkyl group; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; stearyl alcohol; Saturated alcohols such as eicosyl alcohol, behenyl alcohol, carnauvir alcohol, seryl alcohol, melyl alcohol, or long chain alkyl alcohols having a long chain alkyl group; polyhydric alcohols such as sorbitol; linoleic acid amide, oleic acid amide An aliphatic amide such as lauric acid amide; a saturated fatty acid bisamide such as methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide, hexamethylene bis stearic acid amide; Unsaturated fatty acid amides such as oleic acid amide, hexamethylenebisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearic acid amide, N, Aromatic bisamides such as N'-distearylisophthalamide; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (generally referred to as metal soap); aliphatic hydrocarbon waxes Wax grafted with vinyl monomers such as styrene and acrylic acid; partially esterified product of fatty acid and polyhydric alcohol such as behenic acid monoglyceride; methyl having hydroxyl group obtained by hydrogenating vegetable oil Ester compounds It is.

Preferred waxes include polyolefins obtained by radical polymerization of olefins under high pressure; polyolefins obtained by purifying low molecular weight by-products obtained during polymerization of high molecular weight polyolefins; polymerized using catalysts such as Ziegler catalysts and metallocene catalysts under low pressures Polyolefins; polyolefins polymerized using radiation, electromagnetic waves or light; low molecular weight polyolefins obtained by thermally decomposing high molecular weight polyolefins; paraffin wax, microcrystalline wax, Fuchsia-Tropsch wax; Jindole method, hydrocol method, age method Synthetic hydrocarbon waxes synthesized by, etc .; synthetic waxes using a compound having one carbon atom as a monomer, hydrocarbon waxes having a functional group such as a hydroxyl group or a carboxyl group; hydrocarbon waxes having a functional group That a mixture of waxes; styrene these waxes as a matrix, maleic acid ester, acrylate, methacrylate, wax graft-modified with such vinyl monomers of maleic acid.

  In addition, these waxes have a sharp molecular weight distribution using a press sweating method, a solvent method, a recrystallization method, a vacuum distillation method, a supercritical gas extraction method or a melt liquid crystal method, low molecular weight solid fatty acids, low molecular weight solids. An alcohol, a low molecular weight solid compound, and other impurities are preferably used.

Moreover, the addition amount of the wax is preferably 0.1 to 20 parts by mass, and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the binder resin. Two or more kinds of waxes may be used in combination.
The endothermic curve measured by DSC of the toner to which these waxes are added preferably has a maximum peak in the region of 60 to 120 ° C.
When having the maximum peak in these ranges, the fixability and offset resistance are good. When the temperature is lower than 60 ° C., the preservability of the developer itself deteriorates due to the plasticizing effect of the wax. When it exceeds 120 ° C., the fixing property is deteriorated.

  The toner used in the present invention is preferably added with fine silica powder in order to improve charging stability, developability, fluidity and durability. In the present invention, the addition of the silica fine powder is performed by adding the inorganic fine powder and the silica fine powder having improved fluidity to the toner particle surface and having a smaller number average particle size of the primary particles. It was found that the toner can be uniformly dispersed in the toner. When the silica fine powder having a smaller number average particle size is added in combination, the toner cohesive force mitigating effect expressed in combination with the inorganic fine powder may be slightly reduced. In combination, the inorganic fine powder is more uniformly dispersed and adhered to the surface of the toner particles, so that the effect of reducing the toner cohesive force at the transfer nip is more effectively exhibited. If the inorganic fine powder is not uniformly dispersed, the effect of mitigating the cohesive force between the toner particles acting on the toner layer that has become compact in the transfer nip is biased, so that a printed image can be obtained continuously at a high speed for a long period of time. Under such circumstances, the effect of preventing transfer dropout may be reduced.

As the silica fine powder, both so-called dry silica produced by vapor phase oxidation of silicon halide or dry silica called fumed silica, and so-called wet silica produced from water glass can be used. However, dry silica having less silanol groups on the surface and inside of the silica fine powder and less production residue such as Na2 O and SO3- is preferred. In dry silica, it is also possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. Is also included.

  The silica fine powder is preferably hydrophobized. By hydrophobizing the silica fine powder, it prevents the silica fine powder from lowering the chargeability in a high humidity environment and improves the environmental stability of the triboelectric charge amount of the toner particles adhered to the surface of the silica fine powder. Further, it is possible to further improve the environmental stability of development characteristics such as image density and fog as a toner.

Other external additives may be added to the toner used in the present invention as necessary.
Examples thereof include resin fine particles and inorganic fine particles that function as a charging aid, a conductivity imparting agent, a fluidity imparting agent, an anti-caking agent, a release agent at the time of fixing with a heat roller, a lubricant, an abrasive, and the like.
For example, examples of the lubricant include polyethylene fluoride powder, zinc stearate powder, polyvinylidene fluoride powder, and the like. Among these, polyvinylidene fluoride powder is preferable.

The toner used in the present invention can be produced according to any known toner production method. For example, a binder resin, a colorant, other additives, etc. are sufficiently mixed by a mixer such as a Henschel mixer and a ball mill, and then melt-kneaded using a heat kneader such as a heating roll, a kneader, an extruder, After cooling and solidification, pulverization and classification are performed, and if necessary, desired additives are sufficiently mixed by a mixer such as a Henschel mixer to obtain the toner of the present invention.
For example, as a mixer, Henschel mixer (Mitsui Mining Co., Ltd.); Super mixer (Kawata Co., Ltd.); Ribocorn (Okawara Seisakusho Co., Ltd.); Nauter mixer, Turbulizer, Cyclomix (Hosokawa Micron Co., Ltd.); Spiral pin mixer 1 (manufactured by Taiheiyo Kiko Co., Ltd.); Laedige mixer (manufactured by Matsubo Co., Ltd.), and as a kneading machine, KRC kneader (manufactured by Kurimoto Iron Works Co., Ltd.); bus co kneader (manufactured by Buss Co., Ltd.); Machine (manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by Nippon Steel Works); PCM kneader (manufactured by Ikekai Iron Works Co., Ltd.); three roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho Co., Ltd.); MS type pressure kneader, Nider Ruder (Moriyama Seisakusho); Banbury mixer (Kobe Steel Works) As a pulverizer, a counter jet mill, a micron jet, an inomizer (manufactured by Hosokawa Micron Co.); an IDS type mill, a PJM jet pulverizer (manufactured by Nippon Pneumatic Industry Co., Ltd.); a cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); ULMAX (manufactured by Nisso Engineering Co., Ltd.); SK Jet O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo Mill (manufactured by Turboe Industries Co., Ltd.); Examples of classifiers include: class seal, micron classifier, specick classifier (manufactured by Seishin Enterprise Co., Ltd.); turbo classifier (manufactured by Nissin Engineering Co., Ltd.); micron separator, turboplex (ATP), TSP separator (Hosokawa micron) (Made by company) Elbow Jet (manufactured by Nippon Steel & Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Engineering Co., Ltd.); YM Micro Cut (manufactured by Yaskawa Shoji Co., Ltd.) can be mentioned. Ultrasonic (manufactured by Sakae Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (Tokusu Kosakusha Co., Ltd.); Vibrasonic System (manufactured by Dalton Co.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Micro shifter (manufactured by Hadano Sangyo Co., Ltd.), circular vibrating sieve, etc.

  The developing step of the present invention is characterized in that the electrostatic latent image formed on the photoreceptor is developed with toner by a reversal developing method to form a toner image.

    In the case of the reversal development method, when using a negatively chargeable amorphous silicon photoconductor (that is, an amorphous silicon photoconductor that holds a negative charge), a negatively chargeable toner is used, whereas a positively chargeable amorphous silicon photoconductor When the toner is used, a positively chargeable toner is used. There is no difference in image formation when using either of these, but when using a negatively charged amorphous silicon photoconductor, it is widely used as a primary charging means. If a corona discharge type charger is used, a large amount of ozone tends to be generated, and a large amount of discharge products are generated on the photoconductor, which makes it extremely difficult to clean the surface of the photoconductor. In addition, the adhesion of the toner to the surface of the photoreceptor tends to increase. In this case, although depending on the system to be used, particularly in an image forming method in which the transfer member and the photosensitive member are brought into contact with each other and transferred, the surface of the photosensitive member tends to adhere to the contact portion due to the pressure from the transfer member. Tends to occur, and transfer loss tends to occur. On the other hand, when using a positively chargeable amorphous silicon photoconductor, the amount of ozone generated is relatively small even with a general corona discharge type primary charger. It is preferably used because it is less likely to cause problems such as when used. Accordingly, it is preferable to use a positively charged photoreceptor in the reversal development method used in the image forming method of the present invention. Further, it is preferable to use a positively chargeable toner corresponding to the positively chargeable photoreceptor.

In the transfer process and the separation process of the present invention, it is possible to use either a system that is not in contact with the latent image carrier using a corona charger or a contact system that uses a roller or a belt. However, since the transfer means using corona charging has a narrow adsorption area of the transfer material to the photosensitive member and poor transportability in high-speed printing, the transfer medium can run in an endless transfer transport means or a rotating cylindrical shape. The transfer material is sandwiched and conveyed between the endless transfer conveyance means or the transfer medium and the photosensitive member, and an electric field having a polarity opposite to the charging polarity of the toner on the photosensitive member is applied to form a toner image on the photosensitive member. A method of electrostatic transfer onto a transfer material is preferred. In particular, the photosensitive member is brought into contact with the transfer material conveyed by the endless transfer conveying means, and an electric field having a polarity opposite to the charging polarity of the toner on the photosensitive member is applied to statically transfer the toner image on the photosensitive material onto the transfer material. A method of electrically transferring is preferable.
Examples of the endless transfer conveying means include a transfer belt.

Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to the drawings.
FIG. 1 showing an example of the present embodiment is a schematic diagram of a transfer process and a cleaning process using a transfer belt as an endless transfer conveyance unit.

  The photoreceptor 11 has a cylindrical conductive substrate on which a photoconductive layer containing at least amorphous silicon and a surface protective layer containing amorphous silicon and / or amorphous carbon are provided on the conductive substrate. Is supported by two or more rollers (three rollers, a driving roller 13, a driven roller 14, and a cleaning backup roller 17 in FIG. 1) arranged in parallel to each other in a direction substantially perpendicular to the transfer material conveyance direction. It is driven to rotate in the direction of the arrow by a drive motor (not shown). The transfer belt 12 conveys the transfer material 19 in the direction of the arrow while the toner on the photoconductor 11 is pressed onto the transfer material 19 at the contact portion with the photoconductor 11 (that is, the transfer nip portion). Transcript in the original. A bias roller 15 serving as a transfer charge applying unit that applies a transfer bias by applying a transfer bias and a high-voltage power source 16 that applies a voltage to the bias roller 15 are attached to the transfer site. The bias roller 15 is provided so as to contact the inside of the transfer belt 12 at a position slightly downstream of the transfer nip portion in the rotation direction of the transfer belt 12. The bias roller 15 constitutes a contact electrode for applying a charge having a polarity opposite to the charge polarity of the toner developed on the photoreceptor 11 to the transfer belt. The transfer charge applying means may be a charger using corona discharge or a brush-like charger. The installation position of the transfer charge applying unit is not limited to the downstream side in the transfer belt rotation direction with respect to the transfer nip portion, and may be installed in the upstream direction.

The transfer belt 12 is pressed against the photoconductor side with an appropriate pressure from the transfer belt 12 side at the contact portion with the photoconductor 11, and the amount of penetration i of the transfer belt 12 with respect to the surface of the photoconductor 11 is as shown in FIG. The diameter d of the photoconductor 11 is set to be in a range of 0% <i ≦ 5%.
At the drive roller 13 site, the transfer belt 12 and the transfer material 19 are separated by curvature separation. A fur brush 18 is installed on the cleaning backup roller 17 at a position opposite to the transfer belt 12, and the transfer belt surface is cleaned by rotating in the moving direction and counter direction of the transfer belt 12.

  In the present invention, when a transfer belt is used as the endless transfer / conveying means, the toner developed on the photoconductor is always pressed by the transfer belt in the transfer process, and thus is in a consolidated state. Since it is structurally impossible to avoid the pressurization state itself in this transfer process, it is necessary for the toner to have high releasability, thereby effectively preventing the transfer from being lost. be able to.

Further, in the present invention, when a transfer belt is used as the endless transfer conveyance means, the transfer belt is supported by at least two or more rollers installed on the upstream side and the downstream side in the conveyance direction of the portion in contact with the photoreceptor. The intrusion amount i of the transfer belt with respect to the surface of the photosensitive member at the contact portion between the transfer belt and the photosensitive member is preferably in the range of 0% <i ≦ 5% of the photosensitive member diameter d. In the present invention, since the toner on the photosensitive member is pressed from the transfer belt side, the effect of preventing transfer dropout is exhibited. That is, there is no restriction on the width of the transfer nip portion, but when the amount of penetration i of the transfer belt with respect to the surface of the photoreceptor exceeds 5%, image quality deterioration such as transfer blur may be observed during high-speed printing operation.

  In the present invention, since the transfer belt is rotationally driven in a state where tension is applied structurally, it is necessary to have excellent bending characteristics, tear strength characteristics, etc., and the material has more elastic characteristics than the resin type belt. Preferred are rubber and elastomer type belts. In particular, it is preferable to select from materials having low hygroscopicity and stable resistance, such as chloroprene rubber, urethane rubber, EPDM rubber, silicone rubber, and epichlorohydrin rubber. In this case, the structure which has a base material is more preferable.

  As described above, even when a transfer belt is used as the endless transfer conveying means in the present invention and a print image is obtained continuously at a high speed for a long period of time, the transfer assist and separation assist effects by the inorganic fine powders A and B are high. It becomes possible to maintain high-definition and high-quality print quality with reliability.

The cleaning step of the present invention is a step of removing transfer residual toner remaining on the photoconductor after the transfer step from the photoconductor with a cleaning member.
As a cleaning method in the cleaning step, blade cleaning is preferable. Blade cleaning is performed by using an elastic resin such as urethane rubber or silicone rubber as a blade, or by holding a chip-like resin at the tip of a metal blade or the like in the forward or reverse direction with respect to the moving direction of the photoreceptor. The toner remaining on the transfer is removed from the photoreceptor by contact or pressure contact in the direction. Preferably, the blade is pressed against the moving direction of the photoconductor in the opposite direction. At this time, the contact pressure of the blade against the photosensitive member is preferably 0.5 kg / m or more, more preferably 1 to 5 kg / m in terms of linear pressure. Furthermore, a blade cleaning method may be combined with a mug brush cleaning method, a fur brush cleaning method, a roller cleaning method, or the like.
Since the toner of the present invention contains the inorganic fine powder A and the inorganic fine powder B, it can provide appropriate friction and is excellent in releasability and lubricity. Even if the blade is brought into contact with the photosensitive member, it is difficult to be scratched and scraped. In addition, fusion and filming are less likely to occur.

  The cleaning blade preferably has a rubber hardness of 60 to 90 degrees. The rubber hardness of the cleaning blade can be measured using a Wallace rubber hardness meter or Asker rubber hardness meter.

  As the elastic member used in the cleaning blade suitable for the present invention, various known elastic members can be used, for example, urethane rubber. Of these, urethane rubber is most preferably used as the elastic member. In the case of using the elastic member as described above, the peak temperature of the tan δ is, for example, selection of the type of elastic member to be used, use of a reinforcing material such as whisker, use of an elastic member mixed with other compounds, It can be adjusted by selecting the mixing conditions.

In addition to the cleaning blade, the cleaning device preferably includes a cleaning roller that contacts the surface of the electrostatic latent image carrier before the cleaning blade contacts. This cleaning roller is intended to level the residual toner on the electrostatic latent image carrier and to supply the toner stably to the cleaning blade, as long as it can at least achieve such an object. For example, a roller member having appropriate elasticity on the surface can be used as the cleaning roller.

  Furthermore, this cleaning roller preferably includes a magnetism generating means when magnetic toner is used. This magnetism generating means attracts the residual magnetic toner on the electrostatic latent image carrier to the cleaning roller by magnetism, aggregates the magnetic toner, and more reliably removes the magnetic toner with a cleaning blade. There is no particular limitation as long as the object can be achieved. For example, a magnet that generates a certain amount of magnetism, such as a magnet, or an arbitrary magnetism and magnetic pole, such as an electromagnet, may be generated. It may be a thing.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. “Part” and “%” are based on mass unless otherwise specified.

[Inorganic fine powder production example]
<Production Example 1 of Inorganic Fine Powder A>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant reached 80 μS / cm.
0.98-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.5 mol / liter in terms of SrTiO ₃ . The slurry was heated to 85 ° C. at 6 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 80 ° C. After the reaction, the reaction solution was cooled to room temperature, and the supernatant was removed. Then, the washing was repeated with pure water, and then filtered with Nutsche. The obtained cake was dried to obtain strontium titanate fine particles not passing through the sintering step. The strontium titanate fine particles were designated as inorganic fine powder A-1. Table 1 shows the physical properties of the inorganic fine powder A-1.

<Production Example 2 of Inorganic Fine Powder A>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.8 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.
0.95 times the molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, placed in a SUS reaction vessel, and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.75 mol / liter in terms of SrTiO ₃ . The slurry was heated to 75 ° C. at 7 ° C./hour in a nitrogen atmosphere, and reacted for 5 hours after reaching 75 ° C. After the reaction, the reaction solution was cooled to room temperature, and the supernatant was removed. Then, the washing was repeated with pure water, and then filtered with Nutsche. The obtained cake was dried to obtain strontium titanate fine particles not passing through the sintering step. The strontium titanate fine particles were designated as inorganic fine powder A-2. Table 1 shows the physical properties of the inorganic fine powder A-2.

<Production Example 3 of Inorganic Fine Powder A>
The hydrous titanium oxide obtained by hydrolysis by adding ammonia water to an aqueous titanium tetrachloride solution was washed with pure water, and 0.4% sulfuric acid was added to the hydrous titanium oxide slurry as SO _{3 with} respect to the hydrous titanium oxide. Added. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.6 to obtain a titania sol dispersion. NaOH in the titania sol dispersion
Was added, the pH of the dispersion was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant reached 60 μS / cm.
0.97-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.6 mol / liter in terms of SrTiO ₃ . The slurry was heated to 70 ° C. at a rate of 10 ° C./hour in a nitrogen atmosphere, and reacted for 7 hours after reaching 70 ° C. After the reaction, the reaction solution was cooled to room temperature, and the supernatant was removed. Then, the washing was repeated with pure water, and then filtered with Nutsche. The obtained cake was dried to obtain strontium titanate fine particles not passing through the sintering step. The strontium titanate fine particles were designated as inorganic fine powder A-3. Table 1 shows the physical properties of the inorganic fine powder A-3.

<Production Example 4 of Inorganic Fine Powder A>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 4.5, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.
0.97-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Further, distilled water was added so as to be 0.5 mol / liter in terms of SrTiO ₃ .
The slurry was heated to 85 ° C. at 6 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 85 ° C. After the reaction, the mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water.
Further, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 7% by mass of sodium stearate (carbon number 18) is dissolved with respect to the solid content of the slurry, and while stirring, an aqueous zinc sulfate solution is added dropwise to produce perovskite crystals. Zinc stearate was deposited on the surface.
The slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate fine particles whose surface was treated with zinc stearate. The surface-treated strontium titanate fine particles that have not passed through the sintering step are referred to as inorganic fine powder A-4. Table 1 shows the physical properties of the inorganic fine powder A-4.

<Comparative Production Example 1 of Inorganic Fine Powder A>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 4.0 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 8.0, and washing was repeated until the electrical conductivity of the supernatant reached 80 μS / cm.
A 1.05-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.3 mol / liter in terms of SrTiO ₃ . The slurry was heated to 85 ° C. at 30 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 85 ° C. After the reaction, the reaction solution was cooled to room temperature, and the supernatant was removed. Then, the washing was repeated with pure water, and then filtered with Nutsche. The obtained cake was dried to obtain strontium titanate fine particles having an average primary particle diameter of 50 nm. The strontium titanate fine particles were designated as inorganic fine powder A-5. Table 1 shows the physical properties of the comparative inorganic fine powder A-5.

<Comparative Production Example 2 of Inorganic Fine Powder A>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 1.0 to obtain a titania sol dispersion. NaOH is added to the titania sol dispersion, and the p of the dispersion is added.
H was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant liquid reached 100 μS / cm.
A 1.05-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.3 mol / liter in terms of SrTiO ₃ . The slurry was heated to 90 ° C. at 70 ° C./hour in a nitrogen atmosphere, and reacted for 5 hours after reaching 90 ° C. After the reaction, the reaction solution was cooled to room temperature, and the supernatant was removed. Then, the washing was repeated with pure water, and then filtered with Nutsche. The obtained cake was dried to obtain strontium titanate fine particles having an average primary particle size of 310 nm. The strontium titanate fine particles were designated as inorganic fine powder A-6. Table 1 shows the physical properties of the inorganic fine powder A-6.

<Comparative Production Example 3 of Inorganic Fine Powder A>
Dissolve strontium carbonate (SrCO ₃ ) equivalent to Ti in 400 ml of titanium chloride 100 g / l (TiCl ₄ ) aqueous solution and add potassium hydroxide (KOH) equivalent to chlorine ions in the solution under nitrogen atmosphere. The mixture was stirred and heated in a crepe at 160 ° C. for 3 hours. The product was filtered, washed and dried to obtain strontium titanate fine particles having a total amount of particles of 600 nm or more and aggregates of 1.8% by number. This strontium titanate is designated as inorganic fine powder A-7. Table 1 shows the physical properties of the inorganic fine powder A-7.

<Production Example 1 of Inorganic Fine Powder B>
1500 g of strontium carbonate and 800 g of titanium oxide were wet mixed in a ball mill for 8 hours and then filtered and dried. The mixture was molded at a pressure of 8 kg / cm ² and sintered at 1250 ° C. for 8 hours. This was mechanically pulverized with a supermicron mill (manufactured by Hosokawa Micron) to obtain strontium titanate fine particles having an average primary particle diameter of 1200 nm via a sintering process. The strontium titanate fine particles were made into an inorganic fine powder B-1. Table 2 shows the physical properties of the inorganic fine powder B-1.

<Production Examples 2-3 and Comparative Production Examples 1 and 2 of Inorganic Fine Powder B>
In Production Example 1, strontium titanate fine particles B-2 to B-5 having different particle diameters were obtained by adjusting the runner rotation speed and internal air volume of a supermicron mill (manufactured by Hosokawa Micron). Table 2 shows the physical properties of the inorganic fine powders B-2 to B-5.

尚、表１中、「立方体／直方体」とは、「立方体の形状および直方体の形状」が混ざった状態を意味する。

In Table 1, “cube / cuboid” means a state in which “cube shape and cuboid shape” are mixed.

(Manufacture of binder resin for toner)
<Production Example A-1 of High Molecular Weight Component>
-Styrene 78.5 parts by mass-N-butyl acrylate 19.8 parts by mass-Methacrylic acid 2.0 parts by mass-2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane
0.8 parts by mass The above components were added dropwise over 4 hours after the inside of the container was sufficiently replaced with nitrogen and heated to 120 ° C. while stirring 200 parts by mass of xylene in a four-necked flask. Furthermore, the polymerization was completed under reflux of xylene, and the solvent was distilled off under reduced pressure. The resin thus obtained is designated as A-1.

<Production Example A-2 of High Molecular Weight Component>
In Production Example A-1, 80.2 parts by mass of styrene, 20.3 parts by mass of n-butyl acrylate, 0.5 parts by mass of acrylic acid, 2,2-bis (4,4-di-t-butylperoxy (Cyclohexyl) Propane A-2 was obtained under the same conditions as in Production Example A-1, except that the amount was changed to 0.8 parts by mass.

<Production Example A-3 of High Molecular Weight Component>
In Production Example A-1, 74.8 parts by mass of styrene, 18.4 parts by mass of n-butyl acrylate, 7 parts by mass of acrylic acid, 2,2-bis (4,4-di-t-butylperoxycyclohexane (Xyl) Except having changed to 0.8 mass part of propane, it prepared on the same conditions as manufacture example A-1, and obtained resin A-3.

<Production Example A-4 of High Molecular Weight Component>
In Production Example A-1, styrene was changed to 80.3 parts by mass, n-butyl acrylate 20 parts by mass 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane 1 part by mass. Except that, resin A-4 was prepared under the same conditions as in Production Example A-1.

<Production Example A-5 of High Molecular Weight Component>
In Production Example A-1, 72.5 parts by mass of styrene, 18.5 parts by mass of n-butyl acrylate, 9 parts by mass of acrylic acid, 2,2-bis (4,4-di-t-butylperoxycyclohexane Xylyl) Propylene A-5 was prepared under the same conditions as in Production Example A-1, except that the amount was changed to 0.8 parts by mass of propane.

<Production Example B-1 of Vinyl Resin Having Carboxyl Group>
-High molecular weight component resin A-1 30 parts by mass-Styrene 55.6 parts by mass-N-butyl acrylate 14.3 parts by mass-Methacrylic acid 0.7 parts by mass-Di-t-butyl peroxide 1.4 parts by mass The raw material was dropped into 200 parts by mass of xylene over 4 hours. Furthermore, the polymerization is completed under reflux of xylene, the solvent is distilled off under reduced pressure, and the resin thus obtained is designated B-1.

<Production Example B-2 of Vinyl Resin Having Carboxyl Group>
In Production Example B-1, the high molecular weight component resin A-2 was changed to 30 parts by mass, 55.5 parts by mass of styrene, 14 parts by mass of n-butyl acrylate, and 1.2 parts by mass of di-t-butyl peroxide. Except that, resin B-2 was prepared under the same conditions as in Production Example B-1.

<Production Example B-3 of Vinyl Resin Having Carboxyl Group>
In Production Example B-1, 30 parts by mass of high molecular weight component resin A-3, 52.5 parts by mass of styrene, 13.5 parts by mass of n-butyl acrylate, 4 parts by mass of acrylic acid, di-t-butyl peroxide Except having changed to 1.5 mass parts, it prepared on the same conditions as manufacture example B-1, and obtained resin B-3.

<Production example B-4 of vinyl resin having no carboxyl group>
In Production Example B-1, except that the high molecular weight component resin A-4 was changed to 50 parts by mass, 40 parts by mass of styrene, 10 parts by mass of n-butyl acrylate, and 0.8 parts by mass of di-t-butyl peroxide. A resin B-4 was obtained by the same conditions as in Production Example B-1.

<Production Example B-5 of Vinyl Resin Having Carboxyl Group>
In Production Example B-1, 30 parts by mass of high molecular weight component resin A-5, 52.9 parts by mass of styrene, 13.4 parts by mass of n-butyl acrylate, 4.0 parts by mass of acrylic acid, di-t-butyl Except having changed to 1.4 mass parts of peroxide, it prepared on the same conditions as manufacture example B-1, and obtained resin B-5.

<Production Example B-6 of Vinyl Resin Having Carboxyl Group>
In Production Example B-1, the high molecular weight component resin A-2 was changed to 50 parts by mass, 38.5 parts by mass of styrene, 10 parts by mass of n-butyl acrylate, and 1.0 part by mass of di-t-butyl peroxide. Was prepared under the same conditions as in Production Example B-1, and a resin B-6 was obtained.

<Production Example C-1 of Vinyl Resin Having Epoxy Group>
-Styrene 79.5 parts by mass-N-butyl acrylate 19.5 parts by mass-Glycidyl methacrylate 1 part by mass-Di-t-butyl peroxide 5 parts by mass Xylene 200 parts by mass in a four-necked flask While stirring the part, the inside of the container was sufficiently replaced with nitrogen, and the temperature was raised to 120 ° C., followed by dropwise addition over 4 hours. Furthermore, the polymerization is completed under reflux of xylene, the solvent is distilled off under reduced pressure, and the resin thus obtained is designated as C-1.

<Production Example C-2 of Vinyl Resin Having Epoxy Group>
In Production Example C-1, Production Example C-1 except that the content was changed to 72 parts by mass of styrene, 18 parts by mass of n-butyl acrylate, 9.5 parts by mass of glycidyl methacrylate, and 5 parts by mass of di-t-butyl peroxide. Was prepared under the same conditions as in Example 1 to obtain Resin C-2.

<Example 1>
After mixing 90 parts by mass of the vinyl resin having a carboxyl group obtained in Production Example B-1 and 10 parts by mass of the vinyl resin having an epoxy group obtained in Production Example C-1 with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). The binder resin 1 was obtained by kneading at 180 ° C. with a biaxial kneading extruder and cooling and pulverizing.

・ Binder resin 1 100 parts by mass ・ Magnetic iron oxide (0.2 μm) 90 parts by mass ・ Polyethylene wax (melting point 100 ° C.) 4 parts by mass ・ Triphenylmethane lake pigment 2 parts by mass Henschel mixer (Mitsui Mining Co., Ltd.) The mixture was sufficiently premixed and then melt kneaded by a biaxial kneading extruder set at 125 ° C. The obtained kneaded product is cooled, coarsely pulverized with a cutter mill, then finely pulverized using a fine pulverizer using a jet stream, and the obtained finely pulverized product is further classified with an air classifier, and the weight average A classified fine powder (toner particles) having a diameter of 7.4 μm was obtained.
Amino-modified silicone oil (amine equivalent 830, viscosity at 25 ° C., viscosity 70 mm ² / s) per 100 parts by mass of silica fine powder (BET specific surface area 200 m ² / g) produced by a dry method to 100 parts by mass of the obtained classified fine powder ) 0.8 parts by mass of hydrophobic silica treated with 17 parts by mass and 2.0 parts by mass of inorganic fine powder A-1 and 2.0 parts by mass of inorganic fine powder B-1 were added and mixed with a Henschel mixer. Toner 1 was obtained by sieving with a 150 μm mesh. The physical properties of Toner 1 are summarized in Table 3.

The obtained toner 1 was subjected to the following evaluation tests.
The peripheral part of the transfer device of a commercially available digital copying machine iR105 (105 cpm, equipped with a-Si photosensitive drum, magnetic one-component reversal jumping development method, manufactured by Canon Inc.) is modified to the transfer belt type shown in FIG. The a-Si photoconductor was replaced with an a-Si photoconductor drum used in the method of the present invention, and the process speed of the machine body (= the peripheral speed of the photoconductor drum) was modified to 650 mm / sec. The printing speed was 130 cpm.
The a-Si photosensitive drum used in the method of the present invention was produced by a glow discharge method using a gas such as SiH4, H2, CH4, B2H6, GeH4 using a high frequency plasma CVD apparatus.
That is, a long-wavelength absorption layer of hydrogenated a-Si doped with germanium was provided on a substrate which was an aluminum cylinder of φ80 mm. A lower charge injection preventing layer of hydrogenated a-Si doped with boron was provided thereon.
Next, 25 μm of a hydrogenated a-Si photosensitive layer was provided. Next, a hydrogenated a-SiC layer was provided on the top as a surface protective layer to obtain an a-Si photosensitive drum used in the method of the present invention.

In this embodiment, the developing process uses a developing device mounted on the iR 105 and employs a method of reversing and developing the electrostatic latent image on the photosensitive member by a magnetic one-component jumping developing method. As development conditions, a rotatable developing roller including a magnet roller is coated with the magnetic toner of the present invention on a thin layer, a DC bias of +300 V, a Vpp = 1.2 kV, a frequency of 2.7 kHz, a duty wave of 50% rectangular wave. An AC bias was applied. As the setting conditions of the developing device, the distance between the magnetic doctor blade and the developing roller was 210 to 220 μm, the distance from the developing roller to the surface of the photosensitive drum was set to 190 to 210 μm, and the non-contact developing condition was set. The surface potential of the photosensitive drum was developed by setting VD to +380 to +420 V and VL to +30 to +50 V. Chloroplane rubber was used as the surface layer material of the transfer belt, and the intrusion amount i of the transfer belt with respect to the photoreceptor diameter d was set to 3%.

The schematic diagram of the transfer process shown in FIG. 1 has a structure in which the transfer belt 12 is always pressed against the photoconductor 11 for the sake of simplicity of explanation. However, only when the transfer is performed, that is, the transfer material is the photoconductor. It is also preferable to have a so-called separation / contact function that forms a nip by pressing the transfer belt toward the photosensitive member only when contacting with the toner. In this embodiment, the transfer belt 12 is pressed against the photoconductor 11 side except during the start-up operation and the stop operation of the image forming apparatus (that is, while the process speed (= photoconductor surface speed) of the apparatus main body is unstable). I let you. In this embodiment, the peripheral speed of the transfer belt is set to be the same as the peripheral speed of the photoconductor.

In the cleaning process, a cleaning device mounted on the iR105 was used. As shown in FIG. 3, this cleaning device is provided with a cleaning roller 33 in contact with the surface of the photosensitive drum 28 before the cleaning blade contacts, in addition to the cleaning blade 32.
The cleaning roller 33 scrapes off the transfer residual toner on the photosensitive drum 28 by rubbing against the photosensitive drum 28 and uniformly applies the transfer residual toner onto the photosensitive drum 28. Further, when the cleaning roller 33 encloses a magnet (not shown) in the cleaning roller 33, the toner is attracted by the magnetic force of the magnet, and the above-described polishing operation to the photosensitive drum 28 by the cleaning roller 33 causes further toner fusion. Can be prevented. It should be noted that when toner is carried (attracted) on the cleaning roller 33 for a long time, aggregates are likely to be generated, and the generated aggregates are sandwiched between the cleaning blade 32 and the photosensitive drum 28 and cause toner slippage. However, since the inorganic fine powder is present at the edge portion of the cleaning blade 32 to prevent the intrusion of the aggregates, the toner can be prevented from slipping through.
Printed 300,000 copies of text images with an A4 landscape feed in the order of 4% image ratio in the order of normal temperature and normal humidity (23 ° C / 5% RH) and high temperature and high humidity (32 ° C / 90% RH). Endurance tests were performed, and during each endurance test or at the end of the endurance test, each item of image density, fogging, dot reproducibility, transferability (presence of transfer failure or misalignment), drum fusion, and separation was evaluated. . The evaluation was performed according to the following indicators.

1) Image density The reflection density of a 5 mm diameter image was measured using an SPI filter with an “Macbeth reflection densitometer” (manufactured by Macbeth).
A: 1.45 or more B: 1.40 to 1.44
C: 1.30-1.39
D: Less than 1.29

2) Using a fog value “reflection densitometer” (reflectometer model TC-6DS manufactured by Tokyo Denshoku Co., Ltd.), the reflection density (Dr) of the transfer paper before image formation and the reflection density after copying the solid white image The worst value of (Ds) was measured, and the difference (Ds minus Dr) was evaluated as the fog value.
A: Less than 1.0% B: 1.1-2.0%
C: 2.1-3.0%
D: 3.1% or more

3) Dot reproducibility A hiragana character image having a size of 1 mm ² and a dot image of 100 μm ² were drawn, and the images were observed using a 50 × optical microscope, and evaluated according to the following evaluation items. .
A: Characters and dots are reproduced B: Characters are reproduced, but dots are slightly blurred and blurred C: Characters are slightly blurred and blurred, and dots are hardly reproduced D: Characters Do not reproduce both dots and the level at which characters cannot be read

4) Evaluation of transferability In a durability test in each environment, a comprehensive evaluation on the transfer image quality was performed. Specifically, the transfer failure and transfer deviation items were classified into the following evaluation ranks.
A: No transfer failure or transfer deviation B; Minor transfer failure or transfer deviation observed C: Unacceptable transfer failure or transfer deviation observed

6) Evaluation of drum fusion After printing 300,000 sheets continuously in each environment, the photosensitive member and the printed image were visually evaluated and classified into the following evaluation ranks.
A: Almost no fusing is observed on the photoreceptor and the image. B: Slight occurrence is observed on the photoreceptor, but a good image having no problem on the image is obtained.
C: Occurrence was confirmed on the photoconductor, and the image was also slightly visible in halftone.
D: It is confirmed as raining on the solid black image

7) Evaluation of separability After printing 300,000 sheets continuously in each environment, 1,000 sheets of 40 g / m ² of thin paper were passed through to evaluate the occurrence of paper jam.
A: Within 1 time / 1,000 sheets B: 2-4 times / 1,000 sheets C: 5-7 times / 1,000 sheets D: 8 times or more / 1,000 sheets

<Examples 2 to 7>
Toners 2 to 7 are produced by the same preparation method as in Example 1 except that the conditions for inorganic fine powder A and inorganic fine powder B are changed as shown in Table 3, and evaluation is performed in the same manner as in Example 1. It was. The toner physical properties are summarized in Table 3, and the evaluation results are summarized in Table 4.

<Example 8>
90 parts by mass of the vinyl resin having a carboxyl group obtained in Production Example B-2 and 10 parts by mass of the vinyl resin having an epoxy group obtained in Production Example C-1 were mixed in a Henschel mixer, and a twin screw extruder. The mixture was kneaded at 180 ° C. and cooled and pulverized to obtain a binder resin 2.
A toner 8 was produced in the same manner as in Example 7 except that the binder resin 2 was changed. The toner 8 was evaluated in the same manner as in Example 1. The toner physical properties are summarized in Table 3, and the evaluation results are summarized in Table 4.

<Example 9>
95 parts by mass of the vinyl resin having a carboxyl group obtained in Production Example B-3 and 5 parts by mass of the vinyl resin having an epoxy group obtained in Production Example C-1 were mixed in a Henschel mixer, and a twin screw extruder The mixture was kneaded at 180 ° C. and cooled and crushed to obtain a binder resin 3.
A toner 9 was obtained in the same manner as in Example 7 except that the binder resin 3 was changed. The toner 9 was evaluated by the same method as in Example 1. The toner physical properties are summarized in Table 3, and the evaluation results are summarized in Table 4.

<Example 10>
90 parts by mass of the vinyl resin containing no carboxyl group obtained in Production Example B-4 and 10 parts by mass of the vinyl resin having an epoxy group obtained in Production Example C-1 were mixed with a Henschel mixer, and biaxial extrusion was performed. A binder resin 4 was obtained by kneading at 180 ° C. with a machine, cooling and pulverizing.
A toner 10 was obtained in the same manner as in Example 7 except that the binder resin 4 was changed.
This toner 10 was evaluated in the same manner as in Example 1. The toner physical properties are summarized in Table 3, and the evaluation results are summarized in Table 4.

<Example 11>
90 parts by mass of the vinyl resin having a carboxyl group obtained in Production Example B-5 and 10 parts by mass of the vinyl resin having an epoxy group obtained in Production Example C-1 were mixed in a Henschel mixer, and a twin screw extruder. The mixture was kneaded at 200 ° C., cooled and pulverized to obtain a binder resin 5.
A toner 11 was obtained in the same manner as in Example 7 except that the binder resin 5 was changed. This toner 11 was evaluated in the same manner as in Example 1. The toner physical properties are summarized in Table 3, and the evaluation results are summarized in Table 4.

<Examples 12 to 14>
Evaluation was performed under the same conditions as in Example 11 except that the transfer configuration conditions (transfer belt penetration amount i, transfer belt material) of the evaluation machine were the conditions shown in Table 3. The evaluation results are summarized in Table 4.

<Example 15>
For the evaluation machine, Example 14 except that the peripheral part of the transfer device modified in Example 1 was returned to the transfer / separation device (non-contact corona method) mounted on the iR 105 before the modification.
The evaluation was performed under the same conditions. The evaluation results are summarized in Table 4.

<Example 16>
Evaluation was performed under the same conditions as in Example 15 except that the modification was made except for the magnetism generating means contained in the cleaning roller of the evaluation machine. The evaluation results are summarized in Table 4.

<Example 17>
Evaluation was performed under the same conditions as in Example 16 except that the cleaning machine of the evaluation machine was modified by removing the cleaning roller. The evaluation results are summarized in Table 4.

<Comparative Examples 1-5>
Except for changing the inorganic fine powder A and the inorganic fine powder B to the conditions shown in Table 3, toners 12 to 16 were produced under the same conditions as in Example 15 and evaluated with the same evaluation machine and evaluation method as in Example 15. Went. The evaluation results are summarized in Table 4.

（但し、表３中、実施例１０で用いたＢ−４樹脂はカルボキシル基を有しないビニル樹脂である）

(However, in Table 3, the B-4 resin used in Example 10 is a vinyl resin having no carboxyl group)

It is the schematic of the preferable transcription | transfer process in this invention. 2 is a partial cross-sectional view of an example of a photoreceptor including a conductive substrate and a photoconductive layer containing amorphous silicon and a surface protective layer containing amorphous silicon and / or amorphous carbon on the substrate. It is the schematic of the preferable cleaning apparatus in this invention.

Explanation of symbols

11 Photoconductor 12 Transfer belt 13 Drive roller 14 Drive roller 15 Bias roller 16 High-voltage power supply 17 Cleaning backup roller 18 Fur brush 19 Transfer material 21 Conductive substrate 22 Photoconductive layer 23 Surface protective layer 24 Charge injection blocking layer 25 Lower photoconductive layer 26 Upper photoconductive layer 27 Antireflection layer or interface layer 28 Photosensitive drum 29 Charger 30 Exposure device 31 Development device 32 Cleaning blade 33 Cleaning roller

Claims (4)

A charging process for charging the surface of the photoreceptor, a latent image forming process for forming an electrostatic latent image on the photoreceptor by exposure, and a developing process for developing the electrostatic latent image with toner by a reversal development method to form a toner image. A transfer step of electrostatically transferring the toner image to the transfer material, a separation step of separating the transfer material and the photoconductor, and a transfer residual toner remaining on the photoconductor after the transfer step is removed from the photoconductor by a cleaning member. In the image forming method having a cleaning step,
The photoreceptor is provided with a conductive substrate, a photoconductive layer containing at least amorphous silicon and a surface protective layer containing amorphous silicon and / or amorphous carbon on the conductive substrate,
The toner has toner particles containing at least a binder resin and a colorant, at least the particle shape is cubic or rectangular parallelepiped perovskite type crystal and is the number average particle size of less than 300nm or 80nm inorganic fine powder A and, A compound comprising an inorganic fine powder B having a number average particle diameter of 300 nm or more and less than 3000 nm, wherein the inorganic fine powder A and the inorganic fine powder B are both selected from the group consisting of strontium titanate, barium titanate and calcium titanate. An image forming method characterized by the above. The transfer step is a step of transferring the photoconductor in contact with a transfer material conveyed by an endless transfer conveying means,
The endless transfer / conveying means is a transfer belt, and the transfer belt is supported by at least two or more rollers installed on the upstream side and the downstream side in the conveyance direction of a portion in contact with the photoconductor, and the photoconductor in contact portion between, according to claim 1, wherein the intrusion amount i with respect to the photoreceptor surface of the transfer belt is in the range of 5% or less than 0% of said photoreceptor diameter d Image forming method. The binder resin is selected from the group consisting of a vinyl resin having a carboxyl group and a vinyl resin having an epoxy group, a vinyl resin having a carboxyl group and an epoxy group, and a vinyl resin in which a carboxyl group and an epoxy group are reacted. Contains at least the above vinyl resin,
The toner image forming method according to claim 1 or 2 the acid value of the THF-soluble matter is characterized in that it is a 1~50mgKOH / g. When the content (mass%) of the inorganic fine powder A in the toner is Aβ and the content (mass%) of the inorganic fine powder B is Bβ, Aβ / Bβ is 0.1 or more and less than 3.5. the image forming method according to any one of claims 1 to 3, characterized in that there.

Images