JP2011128264A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method which uses a toner having high chargeability and a toner carrier having a high charge imparting property, avoids broadening of a charge amount distribution even in development under a high field strength, and achieves higher image quality. <P>SOLUTION: The image forming method includes a developing step wherein an AC electric field having a peak-to-peak field strength of 2.20×10<SP>6</SP>-7.00×10<SP>6</SP>V/m and a frequency of 2,000-4,000 Hz is applied as a developing bias to a toner carrier, and an electrostatic latent image formed on an electrostatic latent image carrier is developed with a toner supported on the toner carrier. The toner carrier has a substrate and a resin layer, and this resin layer includes a binder resin, a resin including a specific unit and conductive particles. The toner includes toner particles and an inorganic fine powder, the toner has a flow rate index of 1.50-2.50, and the inorganic fine powder has a flow rate index of 0.80-2.00. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming method using an electrophotographic method, an electrostatic recording method, and a magnetic recording method. More specifically, the present invention forms a toner image on a photosensitive member, and then transfers the toner image onto a transfer material to form an image. Toner used in an image forming apparatus such as a copying machine, a printer, or a fax machine, a toner carrier, And an image forming method.

  Conventionally, many methods are known as electrophotographic methods.

  In general electrophotography, a photoconductive substance is used to form an electrical latent image on an image carrier (hereinafter also referred to as a photoreceptor) by various means, and then the latent image is developed. A method is known in which a toner image is obtained by transferring an agent (hereinafter also referred to as toner) to visualize it (hereinafter also referred to as development). The toner image visualized on the photoreceptor is further transferred to a transfer material such as paper as necessary, and then the toner image is fixed on the transfer material by heat / pressure to obtain a copy.

  Among the many development methods known, the one-component development method using magnetic toner has a relatively low price and is focused on running costs because the developer is simple, trouble-free and easy to maintain. It is particularly preferable for a low / medium speed machine.

  These image forming methods using electrophotography are applied as printers and facsimiles in addition to copying machines.

  In recent years, especially in a high-speed machine, image quality and resolution have been improved as commercial use as a digital printing machine becomes more serious. Even in the medium and low speed machines that are required to be lower in price than those high speed machines, high image quality comparable to expensive high speed machines has been demanded.

  Compared to large high-speed machines that are supposed to be installed in dedicated rooms such as printing rooms, small and light medium- and low-speed machines have a variety of installation locations, environments, and usage forms, which are higher. Environmental stability is required.

  In order to achieve high image quality and high definition, it is known to use a toner having high chargeability, for example, by reducing the particle size of the toner (Patent Document 1). In addition, a method is known in which a toner carrier is provided with a resin layer containing a charge control agent on the surface of the carrier to improve the charge imparting performance to the toner (Patent Document 2). Further, there is known a method of developing a high tribotoner having high adhesion to the photosensitive member by increasing the development electric field strength (hereinafter also simply referred to as “electric field strength”) applied during development, and obtaining a high-definition image ( Patent Document 3).

  However, when the above methods are combined in order to achieve higher image quality, it may be difficult to uniformly charge the toner on the toner carrier depending on the environment. Therefore, high image quality cannot be achieved.

  As a method for stabilizing the charging regardless of the environment by improving the toner, for example, a method in which the type of external additive of the toner and the external addition method are devised (Patent Documents 4 and 5) are known. When a toner carrier having a high charge-imparting ability and a high electric field strength are combined, the charge amount distribution that should be stabilized may be broadened depending on the installation environment and usage pattern. When the charge distribution is broadened, blotch (a phenomenon in which the toner layer on the toner carrying member is disturbed due to the charge-up of some toner and appears as spots or wavy unevenness in a black solid image or a halftone image) In addition, since various image abnormalities such as fogging, toner scattering, white spots, and toner deterioration due to selective development occur, high image quality cannot be achieved.

  It was difficult to achieve high image quality regardless of various environments by using a toner with high chargeability and a toner carrier with high chargeability and applying higher electric field strength. It was.

JP 2002-169322 A JP 2001-31136 A JP 2002-202627 A JP 2003-248338 A JP 06-118712 A

  An object of the present invention is to provide an image forming method that solves the problems of the prior art. That is, the object of the present invention is to use a toner having a high chargeability and a toner carrier having a high charge-providing property, and even if development is performed with a high electric field strength, the conventional charge amount distribution is broadened. It is an object of the present invention to provide an image forming method capable of achieving high image quality without causing the above-described problem.

The invention according to the present application for achieving the above-described object is as follows.
(1) The toner carrier has an AC electric field having a peak-to-peak electric field strength of 2.20 × 10 ⁶ V / m or more and 7.00 × 10 ⁶ V / m or less and a frequency of 2000 Hz to 4000 Hz as a developing bias. An image forming method comprising a developing step of developing an electrostatic latent image formed on an electrostatic latent image carrier with a toner applied and carried on the toner carrier,
The toner carrier has at least a substrate and a resin layer formed on the surface of the substrate, and the resin layer contains at least a binder resin and units represented by the following formulas (1) and (2). Containing at least a resin and conductive particles,
The toner is a toner containing at least a toner particle containing a binder resin and a colorant and an inorganic fine powder, and the toner has a flow rate index FRI of 1.50 or more and 2.50 or less. An image forming method, wherein the flow velocity index FRI is 0.80 or more and 2.00 or less.

［式中、Ｒ₁は水素原子またはメチル基を示し、Ｒ₂は炭素数８乃至１８のアルキル基を示す。］

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 8 to 18 carbon atoms. ]

［式中、Ｒ₃は水素原子またはメチル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示し、Ｒ₅、Ｒ_6、Ｒ₇のうち少なくとも一つは炭素数４乃至１８のアルキル基、その他の基は炭素数１乃至１８のアルキル基を示し、Ｘは−ＣＯＯ−、−ＣＯＮＨ−、−Ｃ₆Ｈ₄−のいずれかであり、Ａ^-はハロゲン類、または塩酸、臭化水素酸、硫酸、リン酸、硝酸の無機酸類におけるアニオン、またはカルボン酸、スルホン酸の如き有機酸類におけるアニオンのいずれかである。］
（２）該無機微粉体は、一次粒子の個数平均径が８０ｎｍ以上４００ｎｍ以下であることを特徴とする画像形成方法。
（３）該無機微粉体は、トータルエネルギーＥｔ（１００）が５００ｍＪ以上２０００ｍＪ以下であることを特徴とする画像形成方法。
（４）該無機微粉体が、金属炭酸塩であることを特徴とする画像形成方法。
（５）該無機微粉体が、脂肪酸または脂肪酸の金属塩で表面処理されていることを特徴とする画像形成方法。
（６）該無機微粉体が、炭酸カルシウムを主成分としていることを特徴とする画像形成方法。
（７）該トナー担持体が、該アクリル鎖を有する樹脂中に含有している該ユニット（１）及び（２）のユニット組成比をそれぞれａ、ｂ、としたとき、ｂ／（ａ＋ｂ）が０．５０以上０．９０以下であることを特徴とする画像形成方法。
（８）該トナー担持体が、該結着樹脂１００質量部に対して該アクリル鎖を有する樹脂が１質量部以上４０質量部以下で添加されていることを特徴とする画像形成方法。

[Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and at least one of R ₅ , R _{6 and} R ₇ is an alkyl having 4 to 18 carbon atoms. Group and other groups each represent an alkyl group having 1 to 18 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, and A ⁻ is a halogen, hydrochloric acid, bromide, or the like. Either an anion in an inorganic acid such as hydrogen acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]
(2) The image forming method, wherein the inorganic fine powder has a primary particle number average diameter of 80 nm to 400 nm.
(3) The image forming method, wherein the inorganic fine powder has a total energy Et (100) of 500 mJ or more and 2000 mJ or less.
(4) The image forming method, wherein the inorganic fine powder is a metal carbonate.
(5) The image forming method, wherein the inorganic fine powder is surface-treated with a fatty acid or a metal salt of a fatty acid.
(6) An image forming method, wherein the inorganic fine powder contains calcium carbonate as a main component.
(7) When the unit composition ratios of the units (1) and (2) contained in the resin having the acrylic chain in the toner carrier are a and b, respectively, b / (a + b) is An image forming method, wherein the image forming method is 0.50 or more and 0.90 or less.
(8) The image forming method, wherein the toner carrier is added with 1 to 40 parts by mass of the resin having the acrylic chain with respect to 100 parts by mass of the binder resin.

  As a result of intensive studies on the phenomenon in which the toner whose charge amount distribution should be stable causes a broadening of charging when trying to obtain a higher image quality, The inventors found out that there was a cause in the state of toner rising on the carrier.

  That is, when a toner carrier having high chargeability is used for toner having high chargeability, the toner ears become highly sparse and strongly charged by strongly contacting and rubbing the carrier on the outside of the ears. The toner that is tinged and the toner cannot be contacted with the carrier inside the ear, resulting in a lowly charged toner.

  In the one-component development system using magnetic toner, a magnet for holding and transporting the toner is incorporated inside the toner carrier, and the toner on the carrier forms spikes by magnetic force. The toner is rotated and rubbed on the carrier as ears that are aggregates of toner, and is charged by contacting the surface of the carrier.

  In order to obtain a high image quality and to give a uniform high charge to each particle of the toner, the toner ears that are tall and sparse are changed to toner short and high density toner ears. What is necessary is just to equalize the contact strength and contact opportunity between the carrier and the toner particles.

  Assuming the phenomenon occurring in the fine region, first, when charging a toner having a high chargeability using a toner carrier having a high charge imparting property, the toner was first rubbed and charged with the toner carrier. A potential difference occurs between the toner and the toner that has not yet touched the carrier.

  Since toner having high chargeability has a large potential difference, electrostatic aggregation due to the potential difference is likely to occur, and it is presumed that the aggregation is increased. This weakly agglomerated toner leads to the size of the toner ear, and the toner inside the ear loses the opportunity to contact the carrier, so it is difficult to be charged, the toner outside the ear is strongly charged, and the charge amount distribution is It gets bigger.

  In addition, since the outer side of the strongly charged ear is electrically repelled with the adjacent ear, the ear becomes sparse and further hinders the image quality improvement. The toner on the outside of the spike strongly contacts the surface of the toner carrying member due to the rotational movement of the large spike, and is further strongly charged, thereby causing an image abnormality such as blotch phenomenon or white spots due to charge-up.

  When high electric field strength is applied for the purpose of obtaining high-definition images by breaking the ears during development, even if the ears are highly charged, the charge amount distribution is large when they become toner particles, so the charge amount is low The toner particles cause fogging and toner scattering.

  The present inventors do not cause the above phenomenon by controlling the toner fluidity in a fine region on the toner carrier and making the charge imparting property in the fine region on the surface of the toner carrier uniform. We found that high-quality images can be achieved by making short and dense toner ears.

  The toner carrier in the present invention has at least a base and a resin layer formed on the surface of the base, and the resin layer contains at least a binder resin and units represented by formulas (1) and (2). It contains at least a resin and conductive particles.

  According to the present invention, the ability to impart charge to the toner can be improved by containing the acrylic resin having the structure of the present invention.

  In particular, the ability to impart charge to the toner is improved by the presence effect of the long-chain alkyl group in the cation unit represented by the formula (2). In addition, since the quaternary ammonium base has ionic conductivity, the conductivity of the resin layer is improved. Therefore, since it is possible to suppress excessive charging while quickly applying high charge to the toner, it is possible to reduce image defects such as blotch, ghost, and fog, and high quality with less image scattering with sufficient image density. An image can be obtained.

  In addition, due to the presence of the long chain alkyl group in the acrylic resin, the compatibility with the thermosetting resin is improved due to the presence effect of the long chain alkyl group in the ester unit represented by the formula (1). Thus, the acrylic resin can exist uniformly in the resin layer.

  Furthermore, the dispersibility of the conductive particles present in the resin layer is also improved. As a result, while achieving high charge imparting ability, it is possible to achieve uniform charge imparting properties in a fine region, which is the subject of the present invention, and together with the effects of the toner of the present invention described later, Electrocoagulation can be prevented. Prevents the growth of spikes due to electrostatic agglomeration, so that the toner charge distribution can be maintained sharply, and low-profile and high-density spikes can be formed, resulting in high-definition images and reducing image defects such as blotches. And development characteristics can be improved.

  Furthermore, since the hydrophobicity is increased by the presence of the long-chain alkyl group in the acrylic resin, the moisture resistance is good and the environmental stability is excellent. Therefore, it is possible to stably give appropriate charge to the toner even in a different environment over a long period of time, and accordingly to stably obtain a high-quality image with sufficient image density and less character scattering. Become.

  The toner of the present invention is a toner containing toner particles containing at least a binder resin and a colorant and inorganic fine powder, and the toner has a flow rate index FRI of 1.50 or more and 2.50 or less, The inorganic fine powder has a flow rate index FRI of 0.80 or more and 2.00 or less.

  By combining the toner carrier having an FRI of the toner of 2.50 or less, an FRI of the inorganic fine powder to be added of 2.00 or less, and having a uniform charge imparting property while having the above-mentioned high charge imparting property. , Can achieve a short and dense heading, can achieve high image quality.

  As will be described in detail later, the flow rate index FRI (hereinafter simply referred to as “FRI”) is a numerical value measured by a powder rheometer FT4 (manufactured by Sysmex Corporation, hereinafter also referred to as “FT4”). , The total energy Et (10), which is the sum of the rotational torque and vertical load generated when the rotor blades spirally rotate into the packed particles and rotates at a low speed (rotary blade tip peripheral speed 10 mm / s) and The Et (100) generated during high-speed (100 mm / s) rotation is measured, and the ratio Et (10) / Et (100) is calculated.

  In other words, FRI represents the ratio of fluidity when the powder is moving at a high speed and fluidity when the powder is moving at a slow speed. Indicates that the change in sex is small.

  As a result of studies on the toner charge amount distribution on the toner carrier, the inventors have found that the difference in the toner fluidity in the minute region due to the movement speed is broad and the charge amount distribution is broadened and the spikes are large. I guessed it was the cause.

  The movement of the toner particles in a minute area expanded to a single toner particle per particle on the toner carrier is a rotational movement such as rising and falling on the carrier as a toner ear. The speed is disjoint. If there is a large difference in fluidity between the fast-speed and slow-speed grains, the slow-speed grains have poor fluidity, which further increases the variation in motion speed, and toner with a high motion speed makes strong contact with the toner carrier. As a result, the charge distribution is broadened. When the charge amount distribution becomes broad, the ears become larger due to electrostatic aggregation, and the charge amount distribution becomes broader, resulting in a vicious circle and causing the harms mentioned so far.

  The toner of the present invention has a FRI of 1.50 or more and 2.50 or less, so that the fluidity can be changed even if the difference in the movement speed due to the toner particles seen in a minute region or the movement speed of a certain toner particle changes. Because the change in is small, it is difficult to fall into the vicious circle as described above.

  The toner having an FRI of more than 2.50 corresponds to a squeezed toner having poor fluidity during low-speed motion, or a fluffy toner having good fluidity during high-speed motion. In both cases, the change in fluidity due to the speed of movement is large, leading to a broader charge amount.

  When the FRI is close to 1.00, there is less change in fluidity due to speed, but powder with an FRI of less than 1.50 is heavy powder that does not contain air even during high-speed motion, or has poor mobility, or during low-speed motion Is considered to be a light powder containing air and is not suitable for use as the toner of the present invention.

  The FRI of the toner can be adjusted by the shape, particle size, specific gravity, characteristics of substances constituting the surface, the type and amount of the external additive, and the like. Further, it can be adjusted by the mixing intensity at the time of external addition.

  Further, when the FRI of the inorganic fine powder added to the toner is 0.80 or more and 2.00 or less, the fluidity of the toner in the minute region with respect to the surface of the toner carrier is kept constant.

  When the toner contacts with the surface of the toner carrier and is charged, considering the contact point of contact, not only the fluidity of the toner but also the sliding property between the toner and the surface of the toner carrier is affected by the movement speed. It is important to suppress the charge in order to stabilize the charging.

  In order to solve the problem of the present invention, as a result of intensive studies by the present inventors, not only the fluidity as a toner but also the fluidity of the inorganic fine powder to be added controls the stability with respect to the movement speed. I found it necessary. The added inorganic fine powder is attached to or detached from the surface of the toner, the inorganic fine powder released from the toner is present on the surface of the toner carrier, and the toner and toner are in contact with the inorganic fine powder on the toner surface. It is presumed that the sliding property with the carrier is controlled to some extent.

  When the FRI of the inorganic fine powder added to the toner is 0.80 or more and 2.00 or less, charging can be stabilized regardless of the movement speed of the toner.

  When only an inorganic fine powder having an FRI of more than 2.00 is added, the sliding property between the toner and the toner carrying member changes depending on the contact speed, and the toner motion speed seen in a minute region becomes uneven. When the contact speed of the toner and the toner carrier changes, the amount of charge received by the toner changes, leading to a broader charge amount of the toner, leading to the formation of high and sparse spikes, and a vicious cycle to further broadening the charge amount Will lead to.

  An inorganic fine powder having an FRI of less than 0.80 is considered to be an adhesive powder that creates a cavity during low-speed movement, and deteriorates the fluidity of the toner. It is not suitable for the toner of the present invention to add only.

  The FRI of the inorganic fine powder can be adjusted by the shape, particle size, specific gravity, material properties, etc. of the inorganic fine powder, and surface treatment.

  Examples of the inorganic fine powder include metal oxides such as zinc, aluminum, cerium, cobalt, iron, zirconium, chromium, manganese, strontium, tin, and antimony, and composite metals such as calcium titanate, magnesium titanate, and strontium titanate. Metal salts such as oxides, barium sulfate, calcium carbonate, magnesium carbonate, aluminum carbonate, viscosity minerals such as kaolin, phosphate compounds such as apatite, silica compounds such as silica, silicon carbide, and silicon nitride, carbon black, graphite, etc. Of carbon powder.

  The method for selecting and adjusting the inorganic fine powder is not particularly limited as long as it is within the scope of the present invention.

  Two or more different substances may be selected together, or the same substances with different particle sizes may be selected together. The same substances with different shapes may be mixed, or those with different adjustment methods may be mixed.

  In addition to the inorganic fine powder of the present invention, inorganic fine powder or resin fine particles may be added to the toner of the present invention for various purposes such as imparting fluidity and improving durability.

Using the toner carrier and toner of the present invention, the peak-to-peak electric field strength is 2.2 × 10 ⁶ V / m or more and 7.0 × 10 ⁶ V / m or less, and the frequency is 2000 Hz or more and 4000 Hz or less. An image forming method including a developing step of developing an electrostatic latent image formed on an electrostatic latent image carrier with toner carried on the toner carrier by applying an alternating electric field as a developing bias to the toner carrier. Therefore, high image quality can be achieved.

  Further, in the inorganic fine powder of the present invention, the number average diameter of primary particles is more preferably 80 nm or more and 400 nm or less. When the number average diameter of the primary particles of the inorganic fine powder is within this range, the toner and the toner carrier are greatly involved in the slipping property, and the effect of stabilizing the charging can be further enhanced. By setting the number average diameter within this range, it is presumed that the balance between adhesion to the toner surface and release from the toner will be good, and that it will be less susceptible to the influence of other external additives.

  Furthermore, the inorganic fine powder of the present invention preferably has a total energy Et (100) of 500 mJ or more and less than 2000 mJ. Even with the same FRI, the total energy Et (100) is in the above range, so that when combined with the toner carrier of the present invention, the fluidity becomes a suitable range, and the shape of the spikes is improved. Higher image quality can be achieved.

  Furthermore, the inorganic fine powder of the present invention is more preferably a metal carbonate.

  When a highly durable photoconductor is used for the purpose of reducing the replacement frequency of the photoconductor to reduce running cost, image flow may be a problem in a high humidity environment. By using a metal carbonate as the inorganic fine powder of the present invention, it is possible to preferably remove the charge-generated oxide that has adhered to the surface of the photoreceptor, which causes image flow, while maintaining the effects of the present invention.

  Furthermore, the inorganic fine powder of the present invention is more preferably surface-treated with a fatty acid or a metal salt of a fatty acid. The surface treatment with a fatty acid or a metal salt of a fatty acid can further stabilize the charging stability in a high-humidity environment. In addition, when an elastic blade is used for cleaning a photoconductor, It has the effect of improving body lubricity.

  Furthermore, it is more preferable that the inorganic fine powder of the present invention contains calcium carbonate as a main component. FRI and particle size preferred for the present invention can be easily obtained, and the toner is weakly positively charged, so that it is difficult to cause contamination of the toner carrying member and the photosensitive member, and there is no harmful effect on the image. In view of the low cost, it is preferable to use calcium carbonate.

  Further, when the unit composition ratios of the units (1) and (2) contained in the resin having the acrylic chain in the toner carrier of the present invention are a and b, respectively, b / (a + b) Is more preferably 0.50 or more and 0.90 or less.

  Further, in the toner carrier of the present invention, it is more preferable that the resin having the acrylic chain is added in an amount of 1 part by weight to 40 parts by weight with respect to 100 parts by weight of the binder resin.

It is explanatory drawing of the developing device which has the toner carrier of this invention.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments.

  The toner carrier of the present invention has at least a substrate and a resin layer formed on the surface of the substrate. The resin layer contains at least a binder resin, a resin having a predetermined unit shown below, and conductive fine particles.

  The resin layer formed on the surface of the toner carrier of the present invention preferably contains a thermosetting resin as a binder resin. By using the thermosetting resin as a binder resin, the durability and environmental stability of the resin layer are improved. As the thermosetting resin, phenol resin, melamine resin, urea resin, and benzoguanamine resin are particularly preferable in terms of toughness and durability. Among these, a phenol resin is more preferable because it improves the abrasion resistance of the resin layer, is excellent in environmental stability, and is excellent in compatibility with an acrylic resin described later. Among these thermosetting resins, those that are soluble in alcohols, particularly lower alcohols such as methanol, ethanol, propyl alcohol, and butanol are preferable because of their good compatibility with the acrylic resin used in the present invention.

  The acrylic resin used in the present invention contains at least an ester unit represented by the following formula (1) and a cation unit represented by (2).

［式中、Ｒ₁は水素原子またはメチル基を示し、Ｒ₂は炭素数８乃至１８のアルキル基を示す。］

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 8 to 18 carbon atoms. ]

［式中、Ｒ₃は水素原子またはメチル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示し、Ｒ₅、Ｒ_6、Ｒ₇のうち少なくとも一つは炭素数４乃至１８のアルキル基、その他の基は炭素数１乃至１８のアルキル基を示し、Ｘは−ＣＯＯ−、−ＣＯＮＨ−、−Ｃ₆Ｈ₄−のいずれかであり、Ａ^-はハロゲン類、または塩酸、臭化水素酸、硫酸、リン酸、硝酸等の無機酸類におけるアニオン、またはカルボン酸、スルホン酸の如き有機酸類におけるアニオンのいずれかである。］

[Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and at least one of R ₅ , R _{6 and} R ₇ is an alkyl having 4 to 18 carbon atoms. Group and other groups each represent an alkyl group having 1 to 18 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, and A ⁻ is a halogen, hydrochloric acid, bromide, or the like. Either an anion in an inorganic acid such as hydrogen acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]

A more preferable form of the ester unit represented by the formula (1) is a long chain alkyl wherein R ₁ is a methyl group and R ₂ is selected from a decyl group, an undecyl group, a dodecyl group, a tridecyl group, and a tetradecyl group. It is a group. When the alkyl group is a long chain as described above, the compatibility of the acrylic resin with the binder resin is increased. Therefore, the acrylic resin is uniformly present in the binder resin, and the toner can be uniformly charged. In addition, since the dispersibility of the pigment such as conductive particles in the resin is improved, the resistance distribution is uniform and local charge-up of the toner is suppressed.

When R ₂ is a lower alkyl group having fewer carbon atoms than the range specified in the present invention, the hydrophobicity is lowered, so that the polarity of the entire copolymer is increased. In this case, since the binder resin that can be used in the present invention has a weak polarity, the compatibility of the acrylic resin with the binder resin is deteriorated, and it is difficult for the acrylic resin to be uniformly present in the resin layer. As a result, when the toner comes into contact with the resin layer, the triboelectric charge varies depending on the state of the acrylic resin, and the charge distribution tends to be non-uniform. At the same time, aggregation of the conductive agent is likely to occur, so that leak sites are locally present, and non-uniform charge distribution of the toner is increased.

On the other hand, when R ₂ is a long-chain alkyl group (19 or more carbon atoms) exceeding the octadecyl group, the hydrophobicity is increased, but the crystallinity is increased and the compatibility with the resin or solvent tends to be deteriorated. Resin and acrylic resin are easy to phase separate. Accordingly, in this case as well, the presence of the acrylic resin in the binder resin becomes non-uniform and the conductive agent tends to aggregate, so the toner charge distribution tends to be non-uniform.

As the cation unit represented by the formula (2), those having the following structure are more preferable. At least one selected from R ₃ is a methyl group, R ₄ is a methylene group or ethylene group, R ₅ , R ₆ , and R ₇ is octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group Of the long-chain alkyl groups selected from the group, R ₅ , R ₆ and R ₇ are groups having 1 to 18 carbon atoms, which are not the long-chain alkyl groups.

As described above, the long-chain alkyl group is introduced into at least one selected from R ₅ , R _6, and R ₇ , so that the cation unit that is a charging site is uniformly present in the binder resin, and is added to the toner. On the other hand, it is possible to impart uniform charging. In particular, R ₆ is any one selected from the group consisting of octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, and tetradecyl, and R ₆ and R ₇ are each independently methyl A cationic unit which is a group, an ethyl group or a propyl group is preferred. This is because more uniform charging can be performed. Further, due to the presence of this long-chain alkyl group, the unit of formula (2) tends to exist on the surface of the resin layer. Since the unit of the formula (2) has a cationic property, as a result, the cationic unit increases on the surface of the resin layer, and the negative charge imparting ability to the toner is improved.

A ⁻ is an anion in halogens, hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, nitric acid and other inorganic acids, and organic acids such as carboxylic acid and sulfonic acid. An anion containing a sulfur atom or a halogen atom is preferred, and a halogen such as Br ⁻ or Cl ⁻ is more preferred because of its good compatibility with the thermosetting resin.

  The acrylic resin usable in the present invention can be produced, for example, by copolymerization of an acrylic monomer and an acrylic monomer having a quaternary ammonium base.

  Examples of the acrylic monomer include monomers represented by the following formula (3).

［式中、Ｒ₁は水素原子またはメチル基を示し、Ｒ₂は水素原子、炭素数８乃至１８のアルキル基を示す。］

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents a hydrogen atom or an alkyl group having 8 to 18 carbon atoms. ]

Examples of the monomer represented by the formula (3) include acrylates in which R ₁ is a hydrogen atom, methacrylates in which R ₁ is a methyl group, and R ₂ is a decyl group, an undecyl group, a dodecyl group, or a tridecyl group. A group, a tetradecyl group, or a methacrylate in which R ₁ is a methyl group is preferable.

  Examples of the acrylic monomer having a quaternary ammonium base include a monomer represented by the following formula (4).

［式中、Ｒ₃は水素原子またはメチル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示し、Ｒ₅、Ｒ_6、Ｒ₇のうち少なくとも一つは炭素数４乃至１８のアルキル基、その他の基は炭素数１乃至１８のアルキル基を示し、Ｘは−ＣＯＯ−、−ＣＯＮＨ−、−Ｃ₆Ｈ₄−のいずれかであり、Ａ^-はハロゲン類、または塩酸、臭化水素酸、硫酸、リン酸、硝酸等の無機酸類におけるアニオン、またはカルボン酸、スルホン酸の如き有機酸類におけるアニオンのいずれかである。］

[Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and at least one of R ₅ , R _{6 and} R ₇ is an alkyl having 4 to 18 carbon atoms. Group and other groups each represent an alkyl group having 1 to 18 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, and A ⁻ is a halogen, hydrochloric acid, bromide, or the like. Either an anion in an inorganic acid such as hydrogen acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]

As the monomer represented by the formula (4), it is preferable that at least one of R ₅ , R ₆ and R ₇ is an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, or a tetradecyl group. And R ₄ is preferably a methylene group or an ethylene group. In particular, R ₅ is any one of an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, and a tetradecyl group, and R ₆ and R ₇ are selected from a methyl group, an ethyl group, and a propyl group. It is more preferable that it is an alkyl group. A ⁻ is an anion in halogens, hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, nitric acid and other inorganic acids, and carboxylic acid, sulfonic acid and other organic acids. An anion containing a sulfur atom or a halogen atom is preferable, and a halogen such as Br ⁻ or Cl ⁻ is more preferable.

  In the production process of the acrylic resin usable in the present invention, a known polymerization method can be used. Examples of the method include a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and the like, but a solution polymerization method is preferable because the reaction can be easily controlled. Solvents used in the solution polymerization method are lower alcohols such as methanol, ethanol, n-butanol, and isopropyl alcohol. In addition, other solvents such as xylene, toluene, ethyl acetate, isobutyl acetate, methyl ethyl ketone, methyl isobutyl ketone, N, N-dimethylformamide, dimethylformamide, and the like can be used as necessary. However, in order to improve the compatibility with the binder resin used in the present invention, it is preferable to mainly use a lower alcohol as a solvent. The ratio of the solvent and the comonomer component is preferably 30 to 400 parts by mass with respect to 100 parts by mass of the solvent.

  Polymerization of the monomer mixture can be performed, for example, by heating the monomer mixture to 50 to 100 ° C. in the presence of a polymerization initiator in an inert gas atmosphere. The following are mentioned as an example of the polymerization initiator used in order to superpose | polymerize. t-butylperoxy-2-ethylhexanoate, cumyl perpivalate, t-butylperoxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t-butyl peroxide, t-butyl Cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile) ), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate).

  The polymerization initiators can be used alone or in combination of two or more monomers. Usually, a polymerization initiator is added to the monomer solution to start the polymerization, but a part of the polymerization initiator may be added during the polymerization in order to reduce unreacted monomers. In addition, a method of promoting polymerization by irradiation with ultraviolet rays or an electron beam can be used, and these methods may be combined.

  The amount of the polymerization initiator used is preferably 0.05 parts by mass or more and 30 parts by mass or less, more preferably 0.1 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the copolymerization monomer component. The temperature of the polymerization reaction can be set according to the composition of the solvent to be used, the polymerization initiator, and the copolymerization monomer component, but is preferably 40 ° C or higher and 150 ° C or lower.

  As the monomer of the formula (4), a monomer obtained by quaternizing the monomer represented by the following formula (5) with a quaternizing agent can be used.

［式中、Ｒ₃は水素原子またはメチル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示し、Ｒ₅、Ｒ₆アルキル基を示し、Ｘは−ＣＯＯ−、−ＣＯＮＨ−、−Ｃ₆Ｈ₄−のいずれかである。］

[Wherein, R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, represents an R ₅ or R ₆ alkyl group, and X represents —COO—, —CONH—, — C ₆ H ₄ - is either. ]

  Examples of compounds that can be used as the quaternizing agent include alkyl halides and organic acid compounds.

  Examples of alkyl halides are shown below. Butyl bromide, 2 ethylhexyl bromide, octyl bromide, lauryl bromide, stearyl bromide, butyl chloride, 2 ethylhexyl chloride, octyl chloride, lauryl chloride, stearyl chloride and the like. Examples of organic acid compounds are shown below. methyl p-toluenesulfonate, dimethyl sulfate, methyl hydroxynaphthalenesulfonate, and the like.

  The amount of the quaternizing agent used is preferably 0.8 mol or more and 1.0 mol or less with respect to 1 mol of the monomer represented by the formula (5). Quaternization of such a monomer can be performed, for example, by heating the monomer and the quaternizing agent to 60 ° C. or higher and 90 ° C. or lower in a solvent.

  Further, after copolymerizing the monomer of the above formula (3) and the monomer of the formula (5), further quaternizing with the above quaternizing agent, the desired quaternary ammonium base-containing acrylic copolymer is obtained. It is also possible to obtain. In addition, for example, the monomer represented by the formula (5) is quaternized with an alkyl halide such as methyl chloride and then copolymerized with the monomer represented by the formula (3). The obtained quaternary ammonium base-containing acrylic copolymer is treated with an acid such as p-toluenesulfonic acid and hydroxynaphthalenesulfonic acid to perform counterion exchange, and contains a quaternary ammonium base as a target anion species. An acrylic copolymer can also be used.

  The composition ratio of each unit in the acrylic resin is such that b / (a + b) is 0.50 when the unit composition ratio of the unit (1) in the acrylic resin is a and the unit composition ratio of the unit (2) is b. It is preferable that it is 0.90 or more.

  By setting b / (a + b) to 0.50 or more, the negative charge imparting characteristics of the acrylic resin are improved, and the effect of ionic conductivity due to the quaternary ammonium salt structure is easily enhanced, so that the toner can be charged quickly. Improves. By setting b / (a + b) to 0.90 or less, it becomes possible to uniformly exist in the binder resin. The compatibility with the binder resin becomes good, and the acrylic resin tends to exist uniformly in the resin layer. Furthermore, the dispersibility of the conductive particles present in the resin layer is also improved.

  In addition, in this invention, when the unit which satisfy | fills the structure of said Formula (1), (2) each unit contains multiple types in an acrylic resin, the sum total of the multiple types of unit composition ratio which satisfy | fills the structure of (1) A, and the sum of the composition ratios of the plurality of types satisfying the structure of (2) as b.

  The acrylic resin used in the present invention may contain other units in addition to the units (1) and (2). The content of other units contained in the acrylic resin is preferably 30 mol% or less of the total number [mol] of units constituting the acrylic resin. By making the content rate of other units 30 mol% or less, it is easy to obtain the effect by introducing the units (1) and (2).

  The addition amount of the acrylic resin containing at least the units represented by the above formulas (1) and (2) used in the present invention is 1 part by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the binder resin. preferable. By setting it in this range, the charge control effect by addition can be exhibited, and the film can be uniformly present in the binder resin, so that the coating strength can be maintained.

  In the present invention, in order to adjust the resistance value of the resin layer, the following conductive particles are included in the coating layer. For example, fine powders of metals such as aluminum, copper, nickel, silver, etc., conductive metal oxides such as antimony oxide, indium oxide, tin oxide, titanium oxide, zinc oxide, molybdenum oxide, potassium titanate, crystalline graphite, various Conductive carbon black such as carbon fiber, furnace black, lamp black, thermal black, acetylene black, channel black, and metal fiber.

  Among these, carbon black and graphite are particularly preferable because of excellent dispersibility and excellent electrical conductivity. Among these, conductive amorphous carbon is particularly excellent in electrical conductivity, and can be given a certain degree of conductivity by simply filling a polymer material to impart conductivity and controlling the amount added. Therefore, it is preferably used. In addition, the dispersion stability and coating stability are also improved due to the thixotropic effect of the paint.

  You may use the said electroconductive particle in mixture of 2 or more types. Moreover, the blending amount of the conductive particles is preferably 20 parts by mass or more and 100 parts by mass or less with respect to the binder resin. By setting this range, the resistance value can be set to a desired level without impairing the strength of the resin layer.

In the present invention, the volume resistance of the resin layer on the surface of the toner carrying member is preferably 10 ⁻¹ Ω · cm or more and 10 ² Ω · cm or less. By setting the value within this range, it is possible to prevent the toner from adhering to the toner carrier due to charge-up and the frictional charge improper application from the surface of the toner carrier to the toner caused by the charge-up of the toner. In particular, if the volume resistance value of the resin layer on the surface of the toner carrying member exceeds 10 ² Ω · cm, the frictional charge imparting failure to the toner is likely to occur, and as a result, blotch (spotted image or wave pattern image) and image density decrease occur. It tends to occur.

  Further, in the present invention, in order to make the surface roughness uniform in the conductive resin coating layer and maintain an appropriate surface roughness, it is possible to obtain a more preferable result by adding rough particles for forming irregularities. can get. Spherical particles are preferable as the rough particles for forming the irregularities used in the present invention. By using spherical particles, a desired surface roughness can be obtained with a smaller addition amount than that of amorphous particles, and an uneven surface having a uniform surface shape can be obtained. Furthermore, even when the surface of the coating layer is worn, the change in the surface roughness of the coating layer is small, and the change in the thickness of the toner layer on the toner carrier is unlikely to occur. For this reason, the effect of making the toner charge uniform, sleeve ghosting good, streaking and unevenness hardly occurring, and preventing the toner from being contaminated and fused on the toner carrier can be obtained for a long time. Can be demonstrated across.

  As the base of the toner carrier used in the present invention, there are members such as a cylindrical member, a columnar member, and a belt-like member. A solid bar is preferably used. As such a substrate, a non-magnetic metal or alloy such as aluminum, stainless steel, brass or the like is formed into a cylindrical shape or a cylindrical shape and subjected to treatment such as polishing or grinding is preferably used. These substrates are used after being molded or processed with high accuracy in order to improve the uniformity of the image. For example, the straightness in the longitudinal direction is preferably 30 μm or less, more preferably 20 μm or less, and still more preferably 10 μm or less. Further, the fluctuation of the gap between the sleeve and the photosensitive drum, for example, the deviation of the gap between the sleeve and the vertical surface when the sleeve is rotated by a uniform spacer is preferably 30 μm or less. It is 20 μm or less, more preferably 10 μm or less. Aluminum is preferably used because of material cost and ease of processing.

  In addition, as a base in the case of using a developing method in which the photosensitive drum is brought into direct contact, a cylindrical member having a layer structure including a metal cored bar such as urethane, EPDM, or silicone, or an elastomer is preferably used. In the developing method using magnetic toner, in order to magnetically attract and hold the toner on the toner carrier, a magnet roller or the like in which a magnet is provided is disposed in the toner carrier. In that case, the base may be cylindrical and a magnet roller may be disposed inside the base.

  The conductive resin coating layer can be formed, for example, by dispersing and mixing the components for the conductive resin coating layer in a solvent to form a paint, coating the substrate, and drying, solidifying, or curing. . For dispersing and mixing each component into the coating liquid, a known dispersing apparatus using beads such as a sand mill, a paint shaker, a dyno mill, and a pearl mill can be suitably used. As a coating method, a known method such as a dipping method, a spray method, or a roll coating method can be applied.

  In the present invention, the arithmetic average roughness Ra (JIS B0601-2001) is preferably 0.3 μm or more and 2.5 μm or less, and preferably 0.4 μm or more and 2.0 μm or less as the roughness of the surface of the conductive resin coating layer. More preferably. When Ra on the surface of the conductive resin coating layer is less than 0.4 μm, there is almost no irregularity on the surface of the conductive resin coating layer, so that the amount of toner on the toner carrier becomes unstable and the conductive resin coating layer In some cases, the wear resistance and toner contamination resistance of the toner may be insufficient. On the other hand, when Ra exceeds 2.0 μm, the amount of toner transported on the toner carrier becomes too large, and it becomes difficult to uniformly charge the toner, and the mechanical strength of the conductive resin coating layer also decreases. It may end up.

  The thickness of the conductive resin coating layer configured as described above is preferably 25 μm or less, more preferably 20 μm or less, and even more preferably 4 μm or more and 20 μm or less, in order to obtain a uniform film thickness, The thickness is not particularly limited to this.

  Next, a developing device in which the toner carrier of the present invention is incorporated will be described and exemplified. FIG. 1 is a schematic cross-sectional view of a developing device according to an embodiment having a toner carrier of the present invention. FIG. 1 is merely a schematic illustration of the developing device of the present invention, and it goes without saying that there are various forms in the shape of the toner container (hopper 503), the presence or absence of the stirring blade 510, and the arrangement of the magnetic poles.

  In FIG. 1, an electrostatic latent image carrier that holds an electrostatic latent image formed by a known process, for example, an electrophotographic photosensitive drum 501 is rotated in the direction of arrow B. A developing sleeve 508 serving as a toner carrier carries a one-component toner 504 having magnetic toner supplied by a hopper 503 serving as a toner container containing toner, and rotates in the direction of arrow A. As a result, the toner 504 is conveyed to the developing area D where the developing sleeve 508 and the photosensitive drum 501 face each other. As shown in FIG. 1, in the developing sleeve 508, a magnet roller 505 in which a magnet is inscribed is disposed in order to magnetically attract and hold the toner 504 on the developing sleeve 508.

  A developing sleeve 508 used in the developing device of the present invention has a conductive resin coating layer 507 coated on a metal cylindrical tube 506 as a base. In the hopper 503, a stirring blade 510 for stirring the toner 504 is provided. Reference numeral 513 denotes a gap indicating that the developing sleeve 508 and the magnet roller 505 are in a non-contact state. The toner 504 obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 501 by friction between the magnetic toner constituting the toner and the conductive resin coating layer 507 on the developing sleeve 508. . In the example of FIG. 1, in order to regulate the layer thickness of the toner 504 conveyed to the development area D, a magnetic regulation blade 502 made of a ferromagnetic metal is used as a toner layer thickness regulating member. The blade 502 is suspended from the hopper 503 so as to face the developing sleeve 508 with a gap width of about 50 to 500 μm from the surface of the developing sleeve 508. A magnetic force line from the magnetic pole N 1 of the magnet roller 505 concentrates on the magnetic regulation blade 502, whereby a thin layer of toner 504 is formed on the developing sleeve 508. In the present invention, a nonmagnetic blade can be used instead of the magnetic regulating blade 502.

  Thus, the thickness of the thin layer of the toner 504 formed on the developing sleeve 508 is preferably thinner than the minimum gap between the developing sleeve 508 and the photosensitive drum 501 in the developing region D. The toner carrier of the present invention is particularly effective when incorporated in a developing device that develops an electrostatic latent image with a thin layer of toner as described above, that is, a non-contact type developing device. In the developing region D, the toner carrier of the present invention can also be applied to a developing device in which the thickness of the toner layer is equal to or larger than the minimum gap between the developing sleeve 508 and the photosensitive drum 501, that is, a contact type developing device. it can. In order to avoid complicated explanation, in the following explanation, the non-contact developing device as described above is taken as an example.

  A developing bias voltage is applied to the developing sleeve 508 by a developing bias power source 509 as a biasing unit in order to cause the one-component toner 504 having magnetic toner carried on the developing sleeve 508 to fly. When a DC voltage is used as the developing bias voltage, the developing sleeve 508 has a voltage value between the potential of the image portion of the electrostatic latent image (the region visualized by the toner 504 attached) and the potential of the background portion. It is preferable to apply to.

  In addition, in the case of so-called regular development, a toner charged with a polarity opposite to that of the electrostatic latent image is visualized by attaching toner to the high potential portion of the electrostatic latent image having a high potential portion and a low potential portion. Is used. In the case of so-called reversal development, a toner that is charged to the same polarity as the polarity of the electrostatic latent image is used for visualization by attaching toner to the low potential portion of the electrostatic latent image having a high potential portion and a low potential portion. To do. Here, the high potential and the low potential are expressions based on absolute values. In any of these cases, the toner 504 is charged by at least friction with the developing sleeve 508.

  The toner of the present invention is a toner containing toner particles containing at least a binder resin and a colorant and inorganic fine powder, and the toner has a flow rate index FRI of 1.50 to 2.50, and the inorganic fine powder The body is characterized by a flow velocity index FRI of 0.80 or more and 2.00 or less.

  FRI and Et (100) in the present invention are measured by using FT4. Specifically, the measurement is performed by the following operation.

  In all operations, a 48 mm diameter blade (model number: C210, material: SUS, hereinafter simply referred to as a blade) dedicated to FT4 is used as the propeller blade. This propeller-type blade has a rotation axis in the normal direction at the center of a 48 mm × 10 mm blade plate, and the blade plate has an outermost edge portion (24 mm portion from the rotation shaft) of 70 ° and a portion 12 mm from the rotation shaft. It is smoothly twisted counterclockwise, such as 35 °.

  As the measurement container, a cylindrical split container dedicated to FT4 (model number: C203, material: glass, diameter 50 mm, volume 160 ml, height 82 mm from the bottom surface to the split part, hereinafter may be abbreviated as container) is used.

  In addition, 100 ml of the inorganic fine powder left in an environment of a temperature of 23 ° C. and a humidity of 60% RH for 3 days or more is placed in the measurement container to form a powder layer.

(1) Conditioning operation (a) The propeller blade is rotated clockwise with respect to the powder layer surface so that the peripheral speed of the outermost edge of the blade is 60 mm / sec (the powder layer is loosened by the rotation of the blade). Direction). This blade is moved from the surface of the powder layer at an approach speed at which the angle formed between the locus drawn by the outermost edge of the moving blade and the surface of the powder layer (hereinafter, sometimes referred to as the formed angle) is 5 °. Then, it is made to enter in the vertical direction from the bottom surface of the powder layer to a position of 10 mm. Thereafter, the toner powder layer is rotated while rotating clockwise with respect to the surface of the powder layer so that the peripheral speed of the outermost edge of the blade is 60 mm / sec. The blade is advanced to a position of 1 mm from the bottom surface. Furthermore, while rotating clockwise with respect to the powder layer surface so that the formed angle is 5 ° and the peripheral speed of the outermost edge of the blade is 60 mm / sec, 100 mm from the bottom surface of the powder layer. Move the blade to the position and remove it. When the extraction is completed, the blade is rotated clockwise and counterclockwise alternately, and the inorganic fine powder adhering to the blade is wiped off.
(B) The operations of (1)-(a) are repeated five times to remove air taken in the powder layer.

(2) Split operation The powder layer is ground at the split portion of the above-mentioned FT4 container, and the inorganic fine powder on the upper part of the powder layer is removed. By this operation, the volume of the powder layer can be made the same for each measurement.

(3) Measurement operation (i) Measurement of Et100 (a) Conditioning operation similar to (1)-(a) is performed once.
(B) Rotate the propeller blade counterclockwise with respect to the powder layer surface (direction in which the powder layer is pushed in by rotation of the blade) so that the peripheral speed of the outermost edge of the blade is 100 mm / sec. To do. The blade is advanced in the vertical direction from the powder layer surface to a position 10 mm from the bottom surface of the toner powder layer at an approach speed of 5 °. Thereafter, the blade rotates clockwise with respect to the surface of the powder layer so that the peripheral speed of the outermost edge of the blade is 60 mm / sec, and the angle forming the vertical entry speed to the powder layer becomes 2 °. It is made to approach to the position of 1 mm from the bottom face of the powder layer at the approach speed. Further, the blade is moved to a position of 100 mm from the bottom surface of the powder layer at an angle of 5 ° and extracted. When the extraction is completed, the blade is rotated clockwise and counterclockwise alternately, and the inorganic fine powder adhering to the blade is wiped off.
(C) The operations of (3)-(a) to (b) are repeated six more times, and the rotation obtained when the blade enters the position from 100 mm to 10 mm from the bottom of the toner powder layer in the seventh time. The total Et of the torque and the vertical load is Et (100).
(Ii) Measurement of Et10 (a) First, the conditioning operation similar to the above (1)-(a) is performed once using the toner powder layer for which the measurement of Et100 has been completed.
(B) The same operation as (3)-(b) is performed once.
(C) Perform the same conditioning operation as (1)-(a) once and perform the same operation as (3)-(b) except that the peripheral speed of the outermost edge of the blade is changed to 70 mm / sec. I will do it.
(D) The same conditioning operation as (1)-(a) is performed once, and the same operation as (3)-(b) is performed except that the peripheral speed of the outermost edge of the blade is changed to 40 mm / sec. I will do it.
(E) The same conditioning operation as (1)-(a) is performed once, and the same operation as (3)-(b) is performed except that the peripheral speed of the outermost edge of the blade is changed to 10 mm / sec. I will do it. Let Et (10) be the total Et of rotational torque and vertical load obtained when the blade is moved from the position of 100 mm to the position of 10 mm from the bottom surface of the toner powder layer.

  The method for producing the toner particles is not particularly limited, and the toner particles may be produced by any known method such as a suspension polymerization method, an emulsion polymerization method, an association polymerization method, a kneading and pulverization method.

  As an example, a method for producing the toner of the present invention in the kneading and pulverizing method will be described.

  In the toner of the present invention, a binder resin, a colorant, other additives and the like are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then a heat kneader such as a heating roll, a kneader, or an extruder is used. Melt-knead, cool and solidify, then pulverize and classify.

  In particular, it is preferable to use a mechanical pulverizer as the pulverizing means used in the toner manufacturing method in which the shape of coarse particles is controlled. Examples of the mechanical pulverizer include a pulverizer inomizer manufactured by Hosokawa Micron Corporation, a pulverizer KTM manufactured by Kawasaki Heavy Industries, Ltd., and a turbo mill manufactured by Turbo Industry Co., Ltd. It is preferable to use these apparatuses as they are or after being appropriately modified.

  Furthermore, the inorganic fine powder having a flow rate index FRI of 0.80 or more and 2.00 or less and, if necessary, a desired additive are sufficiently mixed by a mixer such as a Henschel mixer to prepare.

  Alternatively, mixing can be externally added at any time after the production of the toner particles. For example, it can be externally added to the toner in the step of classifying or spheroidizing the toner particles.

  In order to obtain the effect of the present invention, the flow velocity index FRI of the toner needs to be 1.50 or more and 2.50 or less.

  The FRI of the toner can be adjusted by the shape, particle size, specific gravity, characteristics of the material constituting the surface, the type and amount of the external additive, and the like. Further, it can be adjusted by the mixing intensity at the time of external addition.

  For example, when the circularity of the toner is increased, when the specific gravity of the toner base is reduced, or when the strength of mixing during external addition is increased, the FRI of the toner tends to increase.

  As another example, a method for producing the toner of the present invention in the suspension polymerization method will be described.

  First, a low softening point substance, a polar resin, a colorant, a charge control agent, a polymerization initiator, and other additives are added to the polymerizable monomer and uniformly dissolved or dispersed by a homogenizer, an ultrasonic disperser, or the like. The dispersed monomer is added to an aqueous phase containing a dispersion stabilizer, and dispersed with a normal stirrer, homogenizer, homomixer or the like. At this time, granulation is preferably performed by adjusting the stirring speed and time so that the monomer droplets have a desired toner particle size. Thereafter, stirring may be performed to such an extent that the particle state is maintained by the action of the dispersion stabilizer and precipitation of the particles is prevented. The polymerization temperature is preferably set to 40 ° C. or higher, and generally 50 ° C. or higher and 90 ° C. or lower. In addition, the temperature may be raised in the latter half of the polymerization reaction. The partial aqueous medium may be distilled off.

  After completion of the reaction, the produced toner particles are washed, collected by filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by mass of water as a dispersion medium with respect to 100 parts by mass of the monomer system.

  The particle size distribution control and particle size control of the toner particles can be carried out by adjusting the pH of the system during granulation, and changing the kind and amount of a hardly water-soluble inorganic salt or a dispersant that acts as a protective colloid. Alternatively, it is carried out by controlling mechanical apparatus conditions, for example, the circumferential speed of the rotor, the number of passes, the stirring conditions such as the shape of the stirring blades, the container shape or the solid content concentration in the aqueous solution.

  The toner particles produced by the above method are classified as necessary. Hereinafter, similarly to the kneading and pulverization method, the inorganic fine powder having a flow rate index FRI of 0.80 or more and 2.00 or less, and if necessary, desired These additives are sufficiently mixed by a mixer such as a Henschel mixer.

  The toner of the present invention may be produced by any method regardless of the method described above, but has at least an inorganic fine powder having a flow rate index FRI of 0.80 or more and 2.00 or less. Furthermore, it is preferable that Et (100) is 500 mJ or more and 2000 mJ or less.

  The inorganic fine powder of the present invention is more preferably a metal carbonate, and more preferably a surface treatment with a fatty acid or a metal salt of a fatty acid. Furthermore, it is more preferable to use calcium carbonate surface-treated with a fatty acid as the inorganic fine powder of the present invention.

  The number average particle diameter of the inorganic fine powder is preferably 80 nm or more and 400 nm or less, and more preferably 80 nm or more and 200 nm or less.

  The number average particle size of the inorganic fine powder in the present invention is obtained by randomly taking 100 samples from a photograph taken with an electron microscope at a magnification of 50,000 times.

  For spherical particles, the diameter, elliptical spherical shape, or rectangular parallelepiped particles, the average value of the minor axis and the major axis is taken as the particle size of the particles, the average value thereof is obtained, and the average is obtained as the number average particle size. It was.

  A preferable content of the inorganic fine powder contained in the toner of the present invention is 0.01 part by mass or more and 5.0 part by mass or less, more preferably 0.05 part by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the toner particles. 0.0 parts by mass or less.

  In addition to the inorganic fine powder contained in the toner of the present invention, as other external additives, inorganic oxides such as silica, alumina and titanium oxide, inorganic fine powder having a fine particle size such as carbon black and carbon fluoride are used as toner particles. It may be added externally. These impart fluidity and chargeability to the toner.

  If the silica fine powder, alumina fine powder or titanium oxide fine powder dispersed on the surface of the toner particles are fine particles, these fine powders have a high fluidity-imparting effect. Therefore, these fine powders are preferably fine particles. . The number average particle diameter of these fine powders is preferably 5 nm or more and 100 nm or less, and more preferably 5 nm or more and 50 nm or less.

  A preferable addition amount of these inorganic fine powders is 0.03 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the toner particles. When the added amount of the inorganic fine powder is less than 0.03 parts by mass, sufficient fluidity imparting effect cannot often be obtained. On the other hand, when the amount exceeds 5 parts by mass, the compression index of the toner becomes high, the toner is easily tightened, and an excessive external additive is liberated, which tends to have an adverse effect.

  Specific examples of the present invention will be described below, but the present invention is not limited to these examples.

(Inorganic fine powder production example 1)
Using slaked lime powder obtained by dry slaked quicklime with a theoretical water ratio of 1.5, lime milk having a concentration of 450 g / L was prepared and processed with a high-speed impeller disperser.

Next, after adjusting the lime milk to a concentration of 120 g / L, a carbonation reaction was carried out by blowing CO ₂ -containing gas having a CO ₂ concentration of 29 vol% into the lime milk while stirring.

In the carbonation reaction, a CO ₂ -containing gas is blown until the carbonation rate becomes 6.2% at a feed rate of 18 m ³ / m ² · hr as a first stage, and then a feed rate of 1.5 m ³ / The gas was reduced to m ² · hr, and a CO ₂ -containing gas was blown until the carbonation rate reached 12.8%.

Further, as a third stage, the feed rate was increased to 18 m ³ / m ² · hr, and a CO ₂ -containing gas was blown into the reaction until the carbonation rate reached 44.5% to obtain a reaction product.

  1 mol of a calcium hydroxide aqueous suspension having a viscosity of 2500 cp at 25 ° C. and a concentration of 400 g / L was mixed with 1 mol of the obtained reaction product.

A carbon dioxide-containing gas having a carbon dioxide concentration of 30% by volume at a reaction start temperature of 25 ° C. was blown into the obtained mixture at a supply rate of 8.0 m ³ / m ² · hr to carbonate to a carbonation rate of 50.5%. On average, the product was coarsened to a major axis of 3.8 μm and a thickness of 0.4 μm to prepare an aqueous suspension A.

On the other hand, a calcium hydroxide aqueous suspension having a viscosity of 2500 cp at 25 ° C. and a concentration of 400 g / L is adjusted to a concentration of 50 g / L, and a carbon dioxide-containing gas having a carbon dioxide concentration of 30% by volume at a reaction start temperature of 13 ° C. is supplied. Aqueous suspension B was prepared by blowing at 10.0 m ³ / m ² · hr until the carbonation rate was 32.3%.

Next, liquid A and liquid B were mixed so that the molar ratio of Ca-based compound in liquid A and Ca-based compound in liquid B was 100: 8, and the carbon dioxide concentration was 30% by volume at a reaction start temperature of 15 ° C. The carbon dioxide-containing gas was blown at a supply rate of 15 m ³ / m ² · hr and reacted to obtain uniform cubic calcium carbonate having a number average particle size of 100 nm.

  The suspension containing calcium carbonate was repeatedly washed with pure water, and then adjusted to a slurry with a solid content of 10% by mass.

  While stirring the slurry with a disperser at 65 ° C., a fatty acid mixture having a sodium oleate content of 60% by mass, a sodium stearate content of 20% by mass and a sodium palmitate content of 20% by mass was added, After stirring, the press was dehydrated.

  The obtained filter cake was dried with a box dryer and then crushed to obtain calcium carbonate particles treated with a fatty acid mixture.

  This hydrophobized calcium carbonate having a number average particle diameter of 100 nm is defined as inorganic fine powder B1. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Inorganic fine powder production example 2)
Calcium carbonate particles treated with a fatty acid mixture were obtained in the same manner as in Production Example 1 of inorganic fine powder, except that the reaction time of liquid A and liquid B was adjusted to make the number average particle diameter 80 nm.

  This hydrophobized calcium carbonate having a number average particle diameter of 80 nm is designated as inorganic fine powder B2. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Inorganic fine powder production example 3)
Calcium carbonate particles treated with a fatty acid mixture were obtained in the same manner as in Production Example 1 of inorganic fine powder, except that the reaction time of liquid A and liquid B was adjusted so that the number average particle diameter was 150 nm.

  This hydrophobized calcium carbonate having a number average particle diameter of 150 nm is designated as inorganic fine powder B3. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Inorganic fine powder production example 4)
A neutral magnesium carbonate suspension having a composition of MgCO ₃ .3H ₂ O and an average particle size of 20 μm was prepared to a concentration of 50 g / L, and hydrothermal treatment was performed at 200 ° C. for 10 hours while stirring. The obtained suspension was pulverized with a ball mill for 10 hours, and then the solid was converted to anhydrous magnesium carbonate, surface-treated by adding 3% by mass of sodium stearate, and press dehydrated.

  The obtained filter cake was dried with a box dryer and then pulverized to obtain magnesium carbonate particles treated with a fatty acid mixture.

  This hydrophobized magnesium carbonate having a number average particle diameter of 350 nm is designated as inorganic fine powder B4. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Inorganic fine powder production example 5)
Magnesium carbonate particles treated with rosin acid were obtained in the same manner as in Production Example 4 of the inorganic fine powder except that the ball milling time was 15 hours and the surface treating agent was 5% by mass of styrene acrylic rosin acid.

  The hydrophobized magnesium carbonate particles having a number average particle diameter of 150 nm are designated as inorganic fine powder B5. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Inorganic fine powder production example 6)
Into a reaction vessel containing 20 L of 3.0 mol / L sodium hydroxide aqueous solution, 20 L of ferrous sulfate aqueous solution with Fe ²⁺ of 1.5 mol / L is added, the temperature is set to 95 ° C., and ferrous hydroxide colloid A ferrous salt suspension containing was produced.

  The mixture was stirred for 90 minutes while aeration of 100 L / min air was conducted to obtain a ferrous suspension containing magnetite. A 6.0 mol / L aqueous sodium hydroxide solution was added thereto to adjust the pH to 10.0.

  Furthermore, it stirred for 60 minutes, ventilating 100 L / min air, and the magnetite particle | grains were produced | generated. After stirring sufficiently, the magnetite was filtered off. The magnetite was washed with water, dried and then crushed to obtain octahedral magnetite particles.

  This magnetite having a number average particle diameter of 100 nm is designated as inorganic fine powder B6. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Inorganic fine powder production example 7)
Calcium carbonate particles were obtained in the same manner as in Production Example 3 of inorganic fine powder except that the fatty acid compound was not added.

  This calcium carbonate having a number average particle diameter of 150 nm is designated as inorganic fine powder B7. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Inorganic fine powder production example 8)
A mixed gas having a volume ratio of argon and oxygen of 3: 1 is introduced into the reaction vessel to replace the atmosphere. Oxygen gas is supplied into this reaction vessel at 40 (m ³ / hr) and hydrogen gas at 20 (m ³ / hr), and an ignition device is used to form a combustion flame composed of oxygen-hydrogen. Next, a metal silicon powder as a raw material is charged into the combustion flame with a hydrogen carrier gas having a pressure of 12 kg / cm ³ to form a dust cloud. This dust cloud is ignited by a combustion flame and causes an oxidation reaction by dust explosion. After the oxidation reaction, the inside of the reaction vessel was cooled to obtain fine silica powder. 100 parts by mass of this silica fine powder is treated beforehand with 10 parts by mass of hexamethyldisilazane, then treated with 12 parts by mass of dimethyl silicone oil (100 cSt) diluted with hexane, and then heated from room temperature to about 260 ° C. The mixture was then heat-treated, and then dried at 110 ° C. using a fluidized bed dryer, and then sufficiently crushed with a pin mill to obtain silica particles.

  The hydrophobized silica particles having a number average particle diameter of 500 nm are designated as inorganic fine powder B8. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Inorganic fine powder production example 9)
A stirrer, a dropping funnel and a thermometer were set in a glass reactor, and ammonia water was added to ethanol and stirred, and kept at 25 ° C. Next, tetraethoxysilane was dropped into the solution for 60 minutes to react. After completion of the dropping, stirring was further continued at 25 ° C. for 2 hours to obtain a silica sol suspension. Next, this silica sol suspension was heated to remove ethanol, and then toluene was added and further heated to remove water. Next, 3 parts by mass of methylsilane was added to the silica particles in the suspension, and the mixture was reacted at 80 ° C. for 1 hour to hydrophobize the silica. Thereafter, the suspension was heated to remove toluene, dried with a fluid bed dryer, and then pulverized with a pin mill. Then, after quickly dispersing again in the toluene solution, 10 parts by mass of hexamethyldisilazane is added and sufficiently stirred. Then, after making it dry at 110 degreeC using a fluidized bed dryer, it fully disintegrated with the pin mill and obtained the silica particle.

  The hydrophobized silica particles having a number average particle diameter of 40 nm are designated as inorganic fine powder B9. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Inorganic fine powder production example 10)
After adding 148.7 ml of a 1.6 mol / liter aqueous cerium chloride (CeCl ₃ ) solution and 19.7 g of 31% by mass hydrogen peroxide solution in terms of CeO ₂ , pure water was added to make the total amount 200 ml. Hereinafter, this is referred to as a raw material A. On the other hand, a 28 wt% aqueous ammonia, the atomic ratio of Cl contained in the NH ₃ and CeCl ₃ (NH ₃ / Cl) are weighed 65.6ml to be 1.5, this was added pure water total amount Was 200 ml. Hereinafter, this is referred to as a raw material B. Next, both the raw material A and the raw material B were put in a beaker and added dropwise with stirring to precipitate cerium oxide-containing cerium gel. At this time, 50 ml of pure water was previously added to the beaker. Next, this precipitated gel was heat-treated at 150 ° C. for 24 hours in an autoclave to obtain 500 ml of slurry, which was filtered and washed 5 times with pure water, further washed with 200 ml of ethyl alcohol, stirred, filtered and dried under reduced pressure. As a result, a cerium oxide powder was obtained.

  This cerium oxide having a number average particle diameter of 1000 nm is referred to as inorganic fine particles B10. FRI and Et (100) of the obtained inorganic fine powder were measured and shown in Table 1.

(Toner Production Example 1)
(1) Production of polyester resin / Aromatic dicarboxylic acid: 6.2 mol
・ Dodecenyl succinic anhydride: 3.7 mol
-Trimellitic anhydride: 3.3 mol
・ PO-BPA: 7.4 mol
・ EO-BPA: 3.0 mol
The above polyester monomer is charged into an autoclave together with an esterification catalyst, and a condensation polymerization reaction is carried out while heating to 215 ° C. in a nitrogen gas atmosphere with a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device and a stirring device A polyester resin was obtained.

(2) Production of Hybrid Resin Component 80 parts by mass of the polyester resin was dissolved and swollen in 100 parts by mass of xylene.

  Next, 15 parts by mass of styrene, 5 parts by mass of 2-ethylhexyl acrylate, and 0.15 parts by mass of dibutyltin oxide as an esterification catalyst were added and heated to the reflux temperature of xylene. The transesterification reaction with ethylhexyl was started.

  Further, a xylene solution in which 1 part by mass of t-butyl hydroperoxide was dissolved in 30 parts by mass of xylene as a radical polymerization initiator was dropped over about 1 hour.

  The radical polymerization reaction was completed by holding at that temperature for 6 hours.

  By heating to 200 ° C. under reduced pressure to remove the solvent, a transesterification reaction between the hydroxyl group of the polyester resin and 2-ethylhexyl acrylate, which is a copolymer monomer of the vinyl polymer unit, is carried out. The hybrid resin 1 produced by ester-bonding the polymer, the polyester unit and the vinyl polymer unit was obtained.

  The obtained hybrid resin 1 has an acid value of 28.5 mgKOH / g, Tg of 58 ° C., peak molecular weight Mn of 7400, weight average molecular weight Mw of 45000, Mw / Mn of 8.3, THF About 12% by mass of insoluble matter was contained.

(3) Production of toner particles 100 parts by weight of the above hybrid resin 1 7 parts by weight of low molecular weight ethylene-propylene copolymer 2 parts by weight of charge control agent (azo-based iron complex compound) 90 parts by weight of magnetic iron oxide (average) (Particle size 0.19 μm, coercive force 11.2 KA / m, remanent magnetization 10.8 Am ² / kg, saturation magnetization 82.3 Am ² / kg)
The above mixture was melt-kneaded with a twin-screw kneader heated to 130 ° C., and the cooled mixture was coarsely pulverized with a hammer mill.

Further, the pulverization process uses a mechanical pulverizer (Turbo Kogyo Co., Ltd.) turbo mill T-250 type, the gap between the rotor and the stator is 1.5 mm, the tip peripheral speed of the rotor is 115 m / sec, and the conveying air flow rate Was operated at 30 m ³ / h and the supply of the coarsely crushed product was 24 kg / h.

  The obtained finely pulverized product was classified with an air classifier to obtain toner particles in which particles having a weight average diameter of 6.8 μm and 10.1 μm or more were 5.8% by volume.

With respect to 100 parts by mass of the toner particles, 1.0 part by mass of the inorganic fine powder B1, 1.0 part by mass of hydrophobic dry silica (BET specific surface area: 300 m ² / g), and a stirring blade rotation speed of 26. The toner T1 of the present invention was obtained by rotating for 4 minutes with a 67S- ¹ Henschel mixer FM150 (Mitsui Miike). The FRI of the obtained toner was measured and shown in Table 1.

(Toner Production Examples 2 to 11)
Toners T2 to T10 were obtained in the same manner as in Toner Production Example 1 except that the inorganic fine powder to be added was changed to B2 to B10 as shown in Table 1. The FRI of the obtained toner was measured and shown in Table 1.

  The weight average particle diameter (D4) of the toner is calculated as follows. As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. The measurement is performed with 25,000 effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, a special grade sodium chloride dissolved in ion exchange water to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, the dedicated software was set as follows.

  On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic solution is placed in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of electrolyte aqueous solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so that the water temperature is 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker (1) installed in the sample stand, the electrolyte aqueous solution (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. To do. Then, measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set by the dedicated software is the weight average particle diameter (D4).

(Production Example 1 of Acrylic Group-Containing Resin Solution for Toner Carrier)
In a four-neck separable flask equipped with a stirrer, a cooler, a thermometer, a nitrogen inlet tube and a dropping funnel, 46.1 parts by mass of dipropylaminoethyl methacrylate (formula (6)), lauryl bromide (quaternizing agent) ) (Formula (7)) 53.9 parts by mass and 50 parts by mass of ethanol were mixed and stirred until the system was uniform. While continuing to stir, the temperature was raised to 70 ° C. and then stirred for 5 hours to quaternize the monomer, and (2-methacryloyloxyethyl) lauryldipropylammonium bromide (formula ( 8)) was obtained. After cooling the obtained reaction solution, 17.4 parts by mass of tridecyl methacrylate as a copolymer component, 50 parts by mass of ethanol as a solvent, and 1.0 part by mass of azobisisobutyronitrile (AIBN) as a polymerization initiator And stirred until the system was uniform. While continuing the stirring, the temperature in the reaction system was raised to 70 ° C., and the portion charged in the dropping funnel was added over 1 hour. After completion of dropping, the reaction was further continued for 5 hours under reflux with introduction of nitrogen, and further 0.2 parts by mass of AIBN was added, followed by reaction for 1 hour. Further, this solution was diluted with ethanol to obtain an acrylic group-containing resin solution F1 having a solid content of 40%. The mixing ratio is shown in Table 2, and the structure is shown in Table 3.

(Production example of acrylic group-containing resin solutions 2 to 20)
Acrylic group-containing resin solutions F2 to F20 were obtained in the same manner as in the production example of the acrylic group-containing resin solution F1, except that the copolymerization components to be used below were the components shown in Table 4. The structure of the acrylic group-containing resin solution is shown in Table 3.

(Production Example 1 of Conductive Particles for Toner Carrier)
Mesocarbon microbeads obtained by heat treatment of heavy coal oil were washed and dried, then mechanically dispersed with an atomizer mill, and carbonized by primary heat treatment at 800 ° C. in a nitrogen atmosphere. . Next, secondary dispersion was performed with an atomizer mill, followed by heat treatment at 2900 ° C. in a nitrogen atmosphere, and further classification to obtain graphite particles G1 having a volume average particle size of 6.6 μm.

(Production Example 1 of Toner Carrier)
Methanol was added to the following materials to adjust the solid content to 40%, and this was dispersed for 2 hours in a sand mill (using glass beads having a diameter of 1 mm as media particles).
-Binder resin J1 167 parts by mass (solid content 100 parts by mass)
(Resol type phenol resin solution using ammonia catalyst (trade name: J-325, manufactured by DIC Corporation))
-Conductive particles G1 30 parts by mass-Conductive particles G2 50 parts by mass (carbon black # 5500 (trade name, manufactured by Tokai Carbon))
・ Acrylic group-containing resin F1 25 parts by mass (solid content 10 parts by mass)
・ Roughness imparting particles 60 parts by mass (Nikabeads ICB-0520 (Nippon Carbon Co., Ltd .; trade name), average particle size 5.9 μm)

  After separating the glass beads using a sieve, methanol was added so that the solid concentration was 33% to obtain a paint.

  As the base, a cylindrical aluminum tube having an outer diameter of 32.0 mmφ and 24.5 mmφ with an upper and lower end masked and an arithmetic average roughness Ra of 0.2 μm was prepared. The substrate was erected vertically and rotated at a constant speed, and the paint was applied while lowering the spray gun at a constant speed. Subsequently, the coating layer was dried and cured by heating at 150 ° C. for 30 minutes in a hot air drying oven to form a resin layer on the substrate, thereby producing a toner carrier H1. The layer thickness of the resin layer of the toner carrier H1 was 15 μm. Tables 2 to 4 show the structure and physical properties of the resin layer of the toner carrier H1.

(Production Examples 2 to 24 of toner carrier)
Toner carriers H2 to H24 were produced in the same manner as in the toner carrier H1 production example except that the composition of the paint was as shown in Tables 2 to 4.

[Example 1]
A commercially available monochrome multifunction printer iR3045 (manufactured by Canon Inc.) was modified so that the development electric field strength and frequency applied during development can be freely set. The adjustment of the electric field intensity was performed by changing the peak-to-peak voltage of the AC component.

  The toner carrier H1 of the present invention was attached to this apparatus, and a paper passing durability test was performed using the toner T1.

  In the environmental test room where the indoor temperature and humidity can be adjusted, the toner is supplied to the developer in the initial installation mode under the environment of 15 ° C./10% RH, and the electric field strength and frequency are set as shown in Table 5. The solid image density of the initial image and the fogging on the white background were evaluated, and the halftone image was evaluated.

  Next, after continuously passing 10,000 sheets using a document with a printing area of 5%, solid image density and white background fogging evaluation and halftone image evaluation were performed.

  Next, the temperature / humidity in the environmental test chamber was changed to 35 ° C./85% RH over 8 hours, and was further left for 40 hours to evaluate the solid image density and the fogging on the white background.

  In addition, throughout the endurance of paper passing, the presence of other image defects and in-machine toner scattering was confirmed, and if an image abnormality or other defects occurred, the subsequent tests were stopped.

  The solid image density was averaged by measuring five solid portions of the original image with a color reflection densitometer (for example, X-RITE 404A: manufactured by X-Rite Co.).

  For the fog, the whiteness of the white background portion was measured with a reflectometer (densitometer TC6MC: Tokyo Denshoku Technical Center), and the fog amount (%) was calculated from the difference between the whiteness and the average whiteness of the transfer paper.

  From the results of the above paper passing durability test, it is found that there is no occurrence of blotch in a low-humidity environment that is easy to charge up even when developing with a high electric field strength using a toner carrier having high chargeability and high chargeability. Thus, it was confirmed that there was no occurrence of fogging on the white background due to the low charge toner.

  In addition, the charge distribution is maintained sharply even under high temperature and high humidity, where the charge amount tends to decrease, and it has been confirmed that a good image can be obtained with no white background fogging and little fluctuation in image density. It was.

  The evaluation result of the image density and the fogging on the white background was ranked in five stages, and the result was rated as rank 3 or higher. In addition, the half-tone image quality was ranked in three stages, and it was determined to be acceptable at rank B or higher. The evaluation results are shown in Table 5.

[Image density evaluation rank]
Rank 5: Reflection density 1.40 or higher Rank 4: Reflection density 1.35 to 1.39
Rank 3: Reflection density 1.30 to 1.34
Rank 2: Reflection density 1.25 to 1.29
Rank 1: Reflection density 1.24 or less

[White background evaluation rank]
Rank 5: Cover 0.50% or less Rank 4: Cover 0.51 to 1.00%
Rank 3: Cover 1.01 to 1.50%
Rank 2: Fog 1.51 to 3.00%
Rank 1: Cover 3.01% or more

[Halftone evaluation rank]
Rank A: Image quality No abnormalities such as blotch pattern or image disturbance Rank B: Image quality Abnormality such as acceptable image disturbance Rank C: Image quality Unacceptable image abnormality

[Examples 2 to 21 and Comparative Examples 1 to 16]
As shown in Table 5, the toner carriers H2 to H24 and the toners T1 to T10 were used, and the evaluation was performed in the same manner as in Example 1 by changing the electric field strength and frequency. The evaluation results are shown in Tables 5 to 6.

  From the above evaluation results, the effect of the present invention was confirmed.

  In Comparative Examples 1 and 2 in which the FRI of the inorganic fine powder or the FRI of the toner exceeds the upper limit value of the present invention, the toner charge amount distribution is broadened, and blotches are generated in the initial installation, so that a blotch pattern appears in the halftone. It was seen.

  In Comparative Examples 3 to 6 in which the electric field strength or the charging frequency exceeded the range of the present invention, thinning of the density, disturbance of the image, or white spots due to the photoreceptor leak occurred, and the effects of the present invention could not be exhibited.

  In Comparative Examples 7 to 16 in which the resin structure or the composition of the resin layer of the toner carrier exceeds the range of the present invention, the unevenness of charge imparting property, the decrease in charge imparting property, or the decrease in hydrophobicity as described above is within an allowable range. The effect of the present invention was not obtained.

As shown in the results of Examples 1 to 21, the alternating current having a peak-to-peak electric field strength of 2.20 × 10 ⁶ V / m or more and 7.00 × 10 ⁶ V / m or less and a frequency of 2000 Hz or more and 4000 Hz or less. An image forming method comprising a developing step of applying an electric field to a toner carrier as a developing bias and developing an electrostatic latent image formed on the electrostatic latent image carrier with toner carried on the toner carrier, The toner carrier has at least a base and a resin layer formed on the surface of the base, and the resin layer contains a binder resin and at least a unit represented by formulas (1) and (2). The toner contains at least a binder resin and a colorant, and an inorganic fine powder. The toner has a flow rate index FRI of 1.5. 0 to 2.50, and the inorganic fine powder is an image forming method characterized by having a flow rate index FRI of 0.80 or more and 2.00 or less. Even if a toner carrier having a high charge imparting property is used and high electric field strength can be written to improve image quality, good image quality can be obtained regardless of the use environment or use form.

  Further, as shown in Examples 9 to 14, the toner carrier is added with 1 to 40 parts by mass of the resin having the acrylic chain with respect to 100 parts by mass of the binder resin, or the toner. When the unit composition ratios of the units (1) and (2) contained in the resin having the acrylic chain on the support are a and b, respectively, b / (a + b) is 0.50 or more and 0 .90 or less optimizes the balance between high charge imparting property and uniform charge imparting property.

  Furthermore, as shown in Examples 15 to 21, the inorganic fine powder has a primary particle number average diameter of 80 nm to 400 nm, or a total energy Et (100) of 500 mJ to 2000 mJ, or It was a metal carbonate, or it was surface-treated with a fatty acid or a metal salt of a fatty acid, and the calcium carbonate was the main component.

  501 Photosensitive drum, 502 Regulating blade, 503 Toner container (hopper), 504 Toner, 506 Substrate (metal cylindrical tube), 507 Resin coating layer, 508 Toner carrier (developing sleeve)

Claims (8)

An AC electric field having a peak-to-peak electric field strength of 2.20 × 10 ⁶ V / m to 7.00 × 10 ⁶ V / m and a frequency of 2000 Hz to 4000 Hz is applied to the toner carrier as a developing bias; An image forming method comprising a developing step of developing an electrostatic latent image formed on an electrostatic latent image carrier with toner carried on the toner carrier,
The toner carrier has at least a substrate and a resin layer formed on the surface of the substrate, and the resin layer contains at least a binder resin and units represented by the following formulas (1) and (2). Containing at least a resin and conductive particles,
The toner is a toner containing at least a toner particle containing a binder resin and a colorant and an inorganic fine powder, and the toner has a flow rate index FRI of 1.50 or more and 2.50 or less. An image forming method, wherein the flow velocity index FRI is 0.80 or more and 2.00 or less.

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 8 to 18 carbon atoms. ]

[Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and at least one of R ₅ , R _{6 and} R ₇ is an alkyl having 4 to 18 carbon atoms. Group and other groups each represent an alkyl group having 1 to 18 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, and A ⁻ is a halogen, hydrochloric acid, bromide, or the like. Either an anion in an inorganic acid such as hydrogen acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]   2. The image forming method according to claim 1, wherein the inorganic fine powder has a number average diameter of primary particles of 80 nm or more and 400 nm or less.   The image forming method according to claim 1, wherein the inorganic fine powder has a total energy Et (100) of 500 mJ or more and 2000 mJ or less.   The image forming method according to claim 1, wherein the inorganic fine powder is a metal carbonate.   The image forming method according to any one of claims 1 to 4, wherein the inorganic fine powder is surface-treated with a fatty acid or a metal salt of a fatty acid.   The image forming method according to claim 1, wherein the inorganic fine powder contains calcium carbonate as a main component.   When the unit composition ratios of the units (1) and (2) contained in the resin having the acrylic chain on the toner carrier are a and b, respectively, b / (a + b) is 0.50. The image forming method according to any one of claims 1 to 6, wherein the image forming method is 0.90 or less.   8. The toner carrier according to claim 1, wherein the resin having the acrylic chain is added in an amount of 1 part by weight to 40 parts by weight with respect to 100 parts by weight of the binder resin. The image forming method according to item.

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