JP5439709B2 - Image forming method, image forming apparatus, and process cartridge - Google Patents

Description

  The present invention relates to an image forming method using an electrophotographic method, and more particularly to an image forming method, toner, carrier, and image forming apparatus that can be implemented in a high-speed full-color image forming apparatus.

  In recent years, in the technical field of electrophotography, competition for development of color image forming apparatuses capable of high-speed image formation and high image quality is intensifying. Therefore, in order to obtain a full-color image at high speed, in the image forming method, a plurality of electrophotographic photosensitive members are arranged in series, and an image for each color component is formed on each electrophotographic photosensitive member, and superimposed on the intermediate transfer member. Many so-called tandem systems have been adopted that perform batch transfer onto a transfer material.

  In an image forming apparatus that repeats the process of transferring a toner image formed on the surface of an electrophotographic photosensitive member to a transfer material mainly made of paper, residual toner remaining on the electrophotographic photosensitive member without being transferred to the transfer material after transfer is removed. Therefore, it is essential to remove them sufficiently each time. For this reason, various proposals have been made as cleaning means. However, a cleaning blade made of an elastic material such as urethane rubber is used to scrape the residual toner, so that the configuration is simple, compact and low cost. In addition, since the toner removing function is excellent, it is widely used.

  As a rubber material for the cleaning blade, urethane rubber that is high in hardness and rich in elasticity and excellent in wear resistance, mechanical strength, ozone resistance, and the like is generally used. However, in a high-speed image forming apparatus represented by on-demand printing, which has been developed in recent years, there is a tendency for wear and chipping at the tip of the cleaning blade to remarkably deteriorate. It is an issue to be established over the years.

  In addition, the high-speed image forming apparatus as described above is required to form a full-color image with higher image quality, and a developer is designed to improve the image quality. In order to meet the demand for higher image quality, particularly full-color image quality, toners are increasingly becoming smaller in particle size and are being studied to faithfully reproduce latent images. In order to reduce the particle size, a toner manufacturing method using a polymerization method has been proposed as a means for controlling the toner to have a desired toner shape and surface structure (for example, Patent Document 1 and Patent Document 1). 2).

  In the case of the polymerization toner, in addition to controlling the particle size of the toner particles, shape control is possible. In addition, by reducing the particle size together with this, the reproducibility of dots and fine lines can be improved, the pile height (image layer thickness) can be lowered, and higher image quality can be expected. However, when a small particle size toner is used for the blade cleaning method, a higher blade pressing pressure is required for removing the toner as compared with the conventional irregularly pulverized toner. There is a problem that scratches / wear deteriorate.

  In order to solve the above problems in adopting the blade cleaning method in these high-speed image forming apparatuses, the cleaning blade is brought into contact with a high linear pressure, and the surface layer of the electrophotographic photosensitive member contains a charge transport material and nitrogen atoms. By including a binder resin that does not contain and specifying the ratio thereof, the color system high-speed machine does not cause image defects due to poor cleaning, and has a process cartridge having good electrophotographic characteristics and the process cartridge An image forming apparatus has been proposed (see Patent Document 3). However, since the contact of the cleaning blade is a high linear pressure, the cleaning blade and the photoconductor are rapidly worn, and there is concern that it may be difficult to sufficiently satisfy the high durability required for high-speed machines. Is done.

  In addition to this, the outermost layer surface of the electrophotographic photosensitive member is abraded by contact with the cleaning blade and regulates the degree of agglomeration of the powder containing shavings accumulated on the edge of the cleaning blade. An image forming apparatus that can perform good cleaning with spherical toner has also been proposed (Patent Document 4). However, since the toner particle diameter is 5 to 10 μm, a sufficient image cannot be obtained in terms of high image quality required for high durability in a high speed machine, and the toner particle diameter will be further reduced in the future. There is a risk that it will be difficult to establish as a system when progress is made.

Japanese Patent No. 640918 JP-A-6-250439 JP 2006-343658 A Japanese Patent Laid-Open No. 2001-312191

  The present invention has been made in view of the above problems, and in order to form a high-durability and high-quality image in a high-speed full-color machine, even when a small particle size toner is used in a high-speed full-color machine, it is long-term. An object is to provide an image forming method, a toner, a carrier, and an image forming apparatus in which the image forming method can be obtained.

In order to solve the above problems, the invention described in claim 1
At least a charging step for charging the surface of the electrophotographic photosensitive member, an exposure step for performing writing exposure on the surface of the charged electrophotographic photosensitive member, and developing the formed electrostatic latent image with toner to form a toner image on the surface of the electrophotographic photosensitive member. Development step to form, primary transfer step to transfer the formed toner image onto the intermediate transfer member, secondary transfer step to transfer the toner image on the intermediate transfer member onto the transfer material, and fixing the toner image on the transfer material A full-color image forming method having a fixing step and a cleaning step of cleaning the transfer residual toner on the surface of the electrophotographic photosensitive member,
The linear velocity (X) of the electrophotographic photosensitive member is in the range of 430 to 790 mm / sec ,
The toner, even without least include a resin and a colorant, weight average particle diameter of 2 to 6 [mu] m, an average circularity is 0.95 to 0.99, the surface of the toner, at least an average primary particle size 80 to 500 nm of silica is added ,
Present in the powder in the deposition to the performed cleaning process in the electrophotographic photosensitive member surface cleaning blade in contact with the counter direction at a contact pressure 0.15~0.4N / cm with respect to, of the cleaning blade edge The ratio (Sia / Sib) between the amount of silica (Sia) to be added and the amount of silica (Sib) present in the toner before replenishment is 0.0017X + 0.9789 ≦ (Sia / Sib) ≦ 0.0010X + 3.0141. It meets,
The full-color image forming method , wherein the cleaning blade has a hardness (specified by JIS-A hardness / JIS K6253 hardness test) of 70 to 80 ° .

According to a second aspect of the invention, in a full-color image forming method according to claim 1, wherein the toner is characterized in that a toner produced in an aqueous medium.

A third aspect of the present invention is the full color image forming method according to the first or second aspect , wherein the carrier used in the developing step has a weight average particle diameter of 15 to 40 μm.

According to a fourth aspect of the present invention, in the full color image forming method according to any one of the first to third aspects, the cleaning blade has a rebound resilience at 25 ° C. of 20 to 60%.

According to a fifth aspect of the present invention, in the full color image forming method according to any one of the first to fourth aspects, the image forming method is performed by a tandem electrophotographic image forming process.

The invention according to claim 6 is the full color image forming method according to any one of claims 1 to 5 , wherein the fixing step is made of a magnetic metal and is heated by electromagnetic induction, and the heating roller. An endless belt-like toner heating medium that is stretched between the heating roller and the fixing roller, heated by the heating roller, and rotated by these rollers, and the toner heating medium And a pressure roller that rotates in a forward direction with respect to the toner heating medium to form a fixing nip portion.

According to a seventh aspect of the present invention, in the full color image forming method according to any one of the first to sixth aspects, the charging step is performed by a charging unit that applies at least a DC voltage on which an alternating voltage is superimposed. And

According to an eighth aspect of the present invention, in the full-color image forming method according to any one of the first to seventh aspects, the charging in the charging step is performed by bringing a charging member into contact with the electrophotographic photosensitive member and applying a voltage to the charging member. It is carried out by a charging device that performs charging by applying voltage.

The invention according to claim 9 is an electrophotographic photosensitive member for carrying at least a toner image, a charging means for charging the surface of the electrophotographic photosensitive member, and an exposure means for performing writing exposure on the surface of the charged electrophotographic photosensitive member. And developing means for developing the formed electrostatic latent image with toner to form a toner image on the surface of the electrophotographic photosensitive member, and primary transfer for transferring the toner image formed on the surface of the electrophotographic photosensitive member onto the intermediate transfer member Means, secondary transfer means for transferring the toner image on the intermediate transfer member onto the transfer material, fixing means for fixing the toner image on the transfer material, and cleaning for cleaning residual toner on the surface of the electrophotographic photosensitive member. And an image forming method according to any one of claims 1 to 8, wherein the image forming method is implemented.

According to a tenth aspect of the present invention, there is provided a process cartridge for use in the full-color image forming apparatus according to the ninth aspect, wherein the electrophotographic photosensitive member for carrying a toner image, a developing means, and the electrophotographic photosensitive member. It is characterized in that at least one means selected from a charging means for charging the toner and a cleaning means for cleaning the transfer residual toner on the surface of the electrophotographic photosensitive member are integrally supported and detachable from the main body of the image forming apparatus.

According to the image forming method of the present invention, in a high-speed full-color image forming method, even when a small particle size toner is used, good cleaning properties can be obtained over a long period of time.
Also, according to the full color toner of the present invention, good cleaning properties can be obtained over a long period of time even when used in a high speed full color image forming method.
Furthermore, according to the image forming apparatus of the present invention, good cleaning properties can be maintained for a long time even when full color image formation is performed at high speed.

Hereinafter, the present invention will be described in detail.
Linear speed of the electrophotographic photosensitive member (X) is in the range of 430~790mm / sec, even toner without little contained resin and a colorant, weight average particle diameter of 2 to 6 [mu] m, an average circularity is 0. 95 to 0.99, and at least a silica having a primary average particle size of 80 to 500 nm is added to the surface of the toner, and the cleaning means (cleaning step) is applied to the surface of the electrophotographic photosensitive member in the counter direction. performed at contact pressure 0.15~0.4N / cm by the cleaning blade abuts, the amount of silica present in the powder in the deposition to the edge of the cleaning blade (Sia) and the amount of silica present before in the toner replenishing (Sib) the ratio of (Sia / Sib) is, meets the relationship of 0.0017X + 0.9789 ≦ (Sia / Sib ) ≦ 0.0010X + 3.0141, cleaning blade Quality by full-color image forming method hardness (defined in JIS-A hardness / JIS K6253 hardness test) is 70 to 80 °, good reproducibility and sufficient cleaning property over a long term in a high-speed full-color image forming method I was able to get a good image.

  In the present invention, even if a small particle size toner is used in a high-speed full-color image forming method, it is not clear why a sufficient cleaning property can be obtained over a long period of time and an image with good reproducibility can be obtained. Can be considered.

  Normally, the smaller the toner particle size and the closer the shape is to a spherical shape, the easier it is to enter the blade edge. Therefore, the small particle size / spherical toner is formed by contacting the blade and the electrophotographic photosensitive member. It is known that it is easy to slip through the nip portion, and cleaning failure is likely to occur. In particular, when a small particle size / spherical toner is used in a high-speed machine, the speed at which the transfer residual toner enters the blade edge increases, so that the toner is more likely to pass through the nip, and cleaning failure is likely to occur.

  As a means for preventing the toner from entering the nip, a method is known in which an additive released from the toner and the toner itself (in a state where the additive is added) are deposited on the blade edge portion to play a dam-like function. . Further, among these additives, it is known that an additive having a particularly large particle diameter plays the role of a dam. However, if the amount of this additive present in the powder layer deposited on the blade edge is too small, the layer that plays a role of a dam breaks down, and the toner slips through at once, resulting in poor cleaning. Will occur. On the other hand, if the amount of additive in the powder layer deposited on the blade edge is too large, a dam-like effect can be obtained sufficiently, but the additive itself tends to adhere to the surface of the photoconductor. This will cause problems that affect the image.

  On the other hand, in the present invention, in a high-speed full-color image forming method, it was possible to find a range in which good cleaning performance was established with respect to the amount of additive in the powder layer deposited on the blade edge. That is, in the high-speed full-color image forming method, it was possible to find a means for achieving good cleaning properties without occurrence of defective cleaning and without occurrence of filming or medaka due to silica.

Linear speed of the electrophotographic photosensitive member (X) is preferably from 250~800mm / sec in order to achieve high-speed full-color image forming method of the present invention, and more preferably 430~ 790mm / sec. When the linear velocity is less than 250 mm / sec, not only a high-speed full-color image forming method cannot be achieved, but also the blade edge is difficult to stabilize, so even if a dam layer is formed, it will not be maintained for a long time and will collapse immediately. Because of the tendency, the relationship of the present invention does not hold. On the other hand, when the speed is higher than 800 mm / sec, the dam layer tends to be formed and maintained for a long time, but as a side effect, the occurrence of filming and medaka due to silica becomes remarkable, which impairs the image quality improvement. become.

  In order to achieve the object of the present invention, the toner particle diameter is preferably 2 to 6 [mu] m, and particularly preferably 3 to 5 [mu] m. If it is smaller than 2 μm, toner dust is likely to occur in primary transfer and secondary transfer. Conversely, if it is larger than 6 μm, the dot reproducibility becomes insufficient and the graininess of the halftone part also deteriorates. A high-definition image cannot be obtained.

When the linear velocity (X) is in the range of 250 to 800 mm / sec (preferably 430 to 790 mm / sec), the amount of silica present in the powder deposited on the cleaning blade edge and the amount of silica present in the toner before replenishment The ratio (Sia / Sib) preferably satisfies a relationship of 0.0017X + 0.9789 ≦ (Sia / Sib) ≦ 0.0010X + 3.0141.

When the silica amount ratio (Sia / Sib) is smaller than 0.0017X + 0.9789 , a dam layer is not formed with respect to the full width in the longitudinal direction (electrophotographic photosensitive member axial direction) where the toner input of the blade edge is present, or Locations that will fail immediately will occur, or even if a dam layer is formed, there will be locations where the dam layer will not be maintained for a long time, and defective cleaning will be suppressed over the long term Can not do it.

Conversely, if the silica amount ratio (Sia / Sib) is greater than 0.0010X + 3.0141 , a dam layer is formed with respect to the full width in the longitudinal direction (electrophotographic photosensitive member axial direction) where the blade edge toner is input. Therefore, poor cleaning can be suppressed, but because the amount of silica deposited on the blade edge is large, filming and medaka are caused by silica at an early stage, and abnormalities occur. As a result, poor cleaning occurs.

  The average circularity of the toner is preferably from 0.95 to 0.99. When the average circularity is lower than 0.95, the image uniformity during development deteriorates, or the electrophotographic photosensitive member to the intermediate transfer member or The toner transfer efficiency from the intermediate transfer member to the transfer material is lowered, and uniform transfer cannot be obtained. Furthermore, since the amount of toner remaining after transfer increases, the above-mentioned favorable silica amount ratio (Sia / Sib) cannot be obtained, and there is a risk of promoting the occurrence of poor cleaning. On the other hand, if the average circularity of the toner is higher than 0.99, the untransferred toner is likely to rub through the cleaning blade, and as a result, there is a risk of promoting the occurrence of poor cleaning.

  It is preferable to add at least a large particle size silica having a primary average particle size of 80 to 500 nm to the surface of the toner, and it is particularly preferable to add a large particle size silica of 100 to 400 nm. Accordingly, the dam layer is easily formed stably, and the non-electrostatic adhesion force of the toner particles can be reduced by the spacer effect, so that the dam layer is easily cleaned. Furthermore, since the silica is difficult to be buried in the surface of the toner even when the mechanical stress with time is large as in a high-speed machine, the relationship of the silica amount ratio (Sia / Sib) is maintained over a long period of time. It is possible to suppress poor cleaning over a long period of time.

  When the primary average particle diameter of silica is smaller than 80 nm, the dam layer is not formed stably, so that the dam layer is easily broken, and the spacer effect cannot be obtained sufficiently, so that the non-electrostatic adhesion force of the toner particles is sufficient. Therefore, the cleaning is difficult. Furthermore, since the silica is likely to be embedded in the toner surface when the mechanical stress with time is large as in a high-speed machine, the relationship of the silica amount ratio (Sia / Sib) is not maintained over a long period of time. It becomes impossible to suppress the cleaning failure for a long time. On the other hand, when the primary average particle diameter of silica is larger than 500 nm, the silica itself tends to slip through the blade nip, and the toner itself also easily slips from the starting point, resulting in poor cleaning. Further, the fluidity of the toner itself is extremely deteriorated, and the relationship of the silica amount ratio (Sia / Sib) cannot be obtained.

  The proportion of silica added is preferably 0.5 to 5 parts by weight, particularly 1 to 4 parts by weight, based on 100 parts by weight of the toner base. When the added ratio is less than 0.5 parts by weight, the spacer effect cannot be sufficiently obtained, so the non-electrostatic adhesion force of the toner particles cannot be reduced, and cleaning failure is likely to occur. If the amount is more than 5 parts by weight, the fluidity of the toner may be deteriorated and uniform transferability may be hindered, or the amount of silica released from the toner may increase, causing the carrier or the photoreceptor to be spent and contaminated. is there.

The color toner of the present invention is preferably produced and obtained in an aqueous medium, and is particularly effective for obtaining a small particle size and shape in the toner of the present invention.
Examples of the production method include a suspension polymerization method, an emulsion polymerization association method (emulsion polymerization aggregation method), a dissolution suspension method (polymer suspension method), and the like, but are not limited thereto.

<Suspension polymerization method>
A colorant, a release agent and the like are dispersed in an oil-soluble polymerization initiator and a polymerizable monomer, and then emulsified and dispersed by an emulsification method described later in an aqueous medium containing a surfactant and other solid dispersants. Thereafter, a polymerization reaction is performed to form particles, and excess surfactant and the like are washed away to obtain toner particles.

  Polymerizable monomers such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride, acrylamide, methacrylamide, diacetone Functional groups can be introduced on the surface of toner particles by using a part of acrylate or methacrylate such as acrylamide or these methylol compounds, vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethyleneimine, dimethylaminoethyl methacrylate and other amino groups. .

  Further, by selecting a dispersant having an acid group or a basic group as the dispersant to be used, the dispersant can be adsorbed and left on the particle surface to introduce a functional group.

<Emulsion polymerization association method>
A water-soluble polymerization initiator and a polymerizable monomer are emulsified in water using a surfactant, and a latex is synthesized by an ordinary emulsion polymerization technique. Separately, a dispersion in which a colorant, a release agent and the like are dispersed in an aqueous medium is prepared, and after mixing, the toner is aggregated to a toner size and heat-fused to obtain a toner. A functional group can be introduced on the surface of the toner particles by using a latex similar to the monomer that can be used in the suspension polymerization method.

<Polymer suspension method>
As an aqueous medium, water alone may be used, but a solvent miscible with water may be used in combination. Examples of the solvent miscible with water include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.) and the like.

  In the oil phase of the toner composition, a colorant such as resin, prepolymer and pigment, a release agent, a charge control agent and the like are dissolved or dispersed in a volatile solvent.

  In an aqueous medium, an oil phase composed of a toner composition is dispersed in the presence of a surfactant, a solid dispersant and the like, and a prepolymer is reacted to form particles.

  In order to introduce a functional group into the toner particles, a copolymer with a monomer having a functional group used in the suspension polymerization method, or a functional group of an acid group as an acid monomer in the case of a polyester resin is used. It can be obtained by using one having three or more or esterifying the terminal hydroxyl group of the obtained polyester resin with a compound having a plurality of acid groups. Further, as a dispersion stabilizer in an aqueous medium, which will be described later, an acid group-containing surfactant, polar polymer, organic or inorganic resin fine particles can be used, and an acid group can be introduced by remaining on the toner particle surface. Examples of the acid group include a carboxyl group, a sulfone group, a sulfonic acid group, and a phosphoric acid group.

  The carrier particle size is preferably 15 to 40 μm in weight average particle size. When the carrier particle size is smaller than 15 μm, the carrier is likely to be transferred together with the carrier in the transfer step, and conversely, it is more than 40 μm. If it is large, carrier adhesion is unlikely to occur, but if the toner concentration is increased in order to obtain a high image density, there is a possibility that scumming is likely to occur. In addition, when the dot diameter of the latent image is small, the variation in dot reproducibility increases, and the graininess of the highlight portion may be deteriorated.

  The contact pressure of the cleaning blade to the electrophotographic photoreceptor is preferably from 0.15 to 0.4 N / cm, particularly preferably from 0.18 to 0.3 N / cm. When the contact pressure is less than 0.15 N / cm, the pressure contact with the electrophotographic photosensitive member by the cleaning blade is weak, the toner blocking force is remarkably reduced, and it becomes difficult to form a dam layer, and the toner is easy to slip through. Cleaning performance cannot be realized. When the contact pressure exceeds 0.4 N / cm, a large torque is required to rotate the electrophotographic photosensitive member, and blade squeal is likely to occur. Further, the cleaning blade is bent and deformed, and the electrophotographic photosensitive member is in a so-called belly contact state, resulting in poor cleaning. Furthermore, it also promotes wear of the cleaning blade itself.

  The hardness of the cleaning blade (specified by JIS-A hardness / JIS K6253 hardness test) is preferably 70 to 80 °, more preferably 72 to 76 degrees. When the hardness is less than 70 degrees, the cleaning blade itself is soft and wears easily, so that toner slip occurs due to a gap caused by the wear, and the cleaning performance tends to deteriorate with time. Further, when the hardness exceeds 80 °, the cleaning blade is likely to be chipped because it is hard, and the cleaning performance tends to deteriorate with time.

  The rebound resilience (specified by the JIS K6255 rebound resilience test) of the cleaning blade is preferably 20 to 60% at 25 ° C., more preferably 30 to 50%. If the impact resilience is less than 20%, once the toner has slipped through the blade nip, continuous toner slippage will occur at that portion, so cleaning failure is likely to occur, and the impact resilience exceeds 60%. In this case, the stick-slip motion in which the blade edge is slightly vibrated becomes intense, causing the blade edge to become fragile, and cleaning failure tends to occur at an early stage.

  The cleaning blade is made of a polyurethane material. A polyurethane is obtained by reaction of an isocyanate compound and a polyol compound.

  Examples of the isocyanate compound include tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, tolidine diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate. Be

  Examples of the polyol compound include polyether polyol, polyester polyol, acrylic polyol, and epoxy polyol. In addition, as a raw material monomer constituting the acrylic polyol, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, Isobutyl methacrylate, n-hexyl methacrylate, lauryl methacrylate, acrylic acid, methacrylic acid, maleic acid, itaconic acid, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, Examples include acrylamide, N-methylol acrylamide, diacetone acrylamide, glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, and acrylonitrile.

  The image forming method of the present invention is preferably a tandem type having a plurality of electrophotographic photoreceptors, charging means, exposure means, developing means, transfer means, and cleaning means. In a so-called tandem type in which a plurality of electrophotographic photosensitive members are arranged and developed one color at a time of each rotation, a latent image forming process and a developing / transfer process are performed for each color to form a toner image of each color. Therefore, the difference between the single-color image forming speed and the full-color image forming speed is small, and there is an advantage that it can cope with high-speed printing. However, since each color toner image is formed on a separate electrophotographic photosensitive member and each color toner layer is stacked (color overlap) to form a full color image, the chargeability between the toner particles of each color is different. If there is a variation in the characteristics, a difference occurs in the amount of toner developed by toner particles of each color, and the change in the hue of the secondary color due to color superposition increases, in other words, the color reproducibility decreases.

  In the toner used in the tandem type image forming method, the amount of developing toner for controlling the balance of each color is stabilized (there is no variation among the toner particles of each color), and the toner between the toner particles of each color is electronic. The adhesion to the photographic photosensitive member and the transfer material must be uniform. This can be achieved with the toner and carrier of the present invention.

  The fixing unit generally fixes toner by heat and pressure, and includes a heating roller made of magnetic metal and heated by electromagnetic induction, and a fixing roller arranged in parallel with the heating roller. And an endless belt-shaped toner heating medium that is stretched between the heating roller and the fixing roller, heated by the heating roller and rotated by these rollers, and pressed against the fixing roller via the toner heating medium. And a pressure roller that rotates in the forward direction with respect to the toner heating medium to form a fixing nip portion, so that the temperature of the fixing belt rises in a short time and stable temperature control is possible. Become. Even when a transfer material having a rough surface is used, the fixing belt acts in a state corresponding to the surface of the transfer paper to some extent at the time of fixing, so that sufficient fixing properties can be obtained.

Moreover, it is preferable that the charging means applies a DC voltage on which at least an alternating voltage is superimposed.
By applying a DC voltage superimposed with an alternating voltage, the surface potential of the electrophotographic photosensitive member can be stabilized to a desired value compared to the case where only a DC voltage is applied. It becomes.

  Further, the charging means preferably performs charging by bringing a charging member into contact with the electrophotographic photosensitive member and applying a voltage to the charging member. By further charging the electrophotographic photosensitive member with a charging member and applying a voltage to the charging member to perform charging, in particular, the effect of uniform charging obtained by applying a DC voltage superimposed with an alternating voltage can be further improved. Is possible.

  The fixing means is preferably an oilless type or a small amount of oil application type. In order to achieve this, it is preferable to fix the toner particles containing a release agent (WAX) and further finely dispersed in the toner particles. When the release agent is finely dispersed in the toner particles, the release agent is likely to ooze out during fixing, and in an oilless fixing device or when the oil application effect is reduced in a small amount of oil application fixing device. Also, the transfer of toner to the belt side can be suppressed.

  In order for the release agent to exist in a dispersed state in the toner particles, it is preferable that the release agent and the binder resin are not compatible. In order to finely disperse the release agent in the toner particles, for example, there is a method of using a shearing force of kneading at the time of toner production. The dispersion state of the release agent can be determined by observing a thin film slice of toner particles with a TEM. The dispersion diameter of the release agent is preferably small, but if it is too small, there are cases where the seepage during fixing is insufficient. Therefore, if the release agent can be confirmed at a magnification of 10,000, it is determined that the release agent exists in a dispersed state. If the size is 10,000 times and the release agent cannot be confirmed, even if finely dispersed, there is a case where the bleeding at the time of fixing is insufficient.

(Toner characteristic evaluation method)
<Weight average particle diameter (D4), volume average particle diameter (Dv), and number average particle diameter (Dn)>
The weight average particle diameter (D4), volume average particle diameter (Dv), and number average particle diameter (Dn) of the toner are measured using a particle size measuring device (“Multisizer III” manufactured by Beckman Coulter, Inc.) with an aperture diameter of 100 μm. It measured and analyzed with the analysis software (Beckman Coulter Multisizer 3 Version3.51). Specifically, 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate: Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a glass 100 ml beaker, and 0.5 g of each toner is added. The mixture was stirred, and then 80 ml of ion exchange water was added. The obtained dispersion was subjected to a dispersion treatment for 10 minutes with an ultrasonic disperser (W-113MK-II, manufactured by Honda Electronics Co., Ltd.). The dispersion was measured using the Multisizer III and Isoton III (manufactured by Beckman Coulter) as the measurement solution. In the measurement, the toner sample dispersion was dropped so that the concentration indicated by the apparatus was 8 ± 2%. In this measurement method, it is important that the concentration is 8 ± 2% from the viewpoint of the reproducibility of the particle size. Within this concentration range, no error occurs in the particle size.

<Average circularity>
The average circularity of the toner is defined by the average circularity SR = (peripheral length of a circle having the same area as the particle projection area / perimeter length of the particle projection image) × 100%. Measurement was performed using a flow type particle image analyzer (“FPIA-2100”; manufactured by Sysmex Corporation), and analysis was performed using analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10). Specifically, 0.1 to 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate: Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a glass 100 ml beaker, and each toner 0.1. ˜0.5 g was added and stirred with microspatel, and then 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 3 minutes with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.). The shape and distribution of the toner were measured using the FPIA-2100 until the density of the dispersion was 5000 to 15000 / μl.

  In this measurement method, it is important that the concentration of the dispersion liquid is 5000 to 15000 / μl from the viewpoint of measurement reproducibility of the average circularity. In order to obtain the dispersion concentration, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above. If it is added in a large amount, noise due to bubbles is generated, and if it is too small, the toner cannot be sufficiently wetted. It will be enough. Further, the toner addition amount differs from the particle size, and it is necessary to decrease the small particle size and increase the large particle size. When the toner particle size is 3 to 7 μm, the toner amount is 0.1 to 0. By adding 0.5 g, the dispersion concentration can be adjusted to 5000 to 15000 / μl.

<Silica content>
3g of New toner before replenishing the development unit was molded into pellets with a diameter of 4cm and a thickness of 2mm with an automatic pressure molding machine (T-BRE-32 made by Maekawa) with a load of 6.0t and a pressing time of 60sec. Then, remove burrs from the pellet edge and surface deposits to make a measurement sample.

  The pellets thus prepared are subjected to quantitative analysis with a fluorescent X-ray (ZSX-100e, manufactured by Rigaku Corporation) under the conditions of a tube voltage of an X-ray tube of 50 kV and a tube current of 10 mA.

  Quantitative analysis refers to the preparation of several samples in which the amount of silica added to the base toner is known in advance, changing the amount of silica to be added, and measuring the sample with fluorescent X-rays to determine the silica count. In this method, a calibration curve is created and the number of silica parts of the sample to be obtained is calculated by using the calibration curve. In the present invention, three samples obtained by adding 1 part by weight, 3 parts by weight, and 9 parts by weight of silica to 100 parts by weight of the same toner base were used as samples for obtaining the calibration curve.

As described above, the amount of silica (Sib) present in the toner before replenishment is obtained.
Further, the amount of silica (Sia) present in the powder deposited on the cleaning blade edge is obtained in the same manner as described above by collecting the powder deposited on the blade edge after outputting 100 sheets of running.

(Carrier characteristics evaluation method)
<Weight average particle size>
The weight average particle diameter Dw of the carrier is calculated based on the particle diameter distribution (relationship between the number frequency and the particle diameter) of the particles measured on the basis of the number. The weight average particle diameter Dw in this case is represented by the formula (1).

(Equation 1)
Dw = {1 / Σ (nD ³ )} × {Σ (nD ⁴ )} (1)
In formula (1), D represents the representative particle size (μm) of the particles present in each channel, and n represents the total number of particles present in each channel. The channel indicates a length for equally dividing the particle size range in the particle size distribution diagram, and 2 μm is adopted in the present invention. In addition, as the representative particle size of the particles present in each channel, the lower limit value of the particle size of the particles stored in each channel was adopted.

  Further, the number average particle diameter Dp of the carrier and the core material particles of the carrier is calculated based on the particle diameter distribution of the particles measured on the basis of the number. The number average particle diameter Dp in this case is represented by the formula (2).

(Equation 2)
Dp = (1 / ΣN) × (ΣnD) (2)
In formula (2), N represents the total number of particles measured, n represents the total number of particles present in each channel, and D represents the lower limit of the particle size of the particles stored in each channel (2 μm). Show.

In the present invention, a microtrack particle size analyzer model HRA9320-X100 (manufactured by Honeywell) can be used as a particle size analyzer for measuring the particle size distribution. The measurement conditions are as follows.
[1] Particle size range: 8 to 100 μm
[2] Channel length (channel width): 2 μm
[3] Number of channels: 46
[4] Refractive index: 2.42

Hereinafter, the toner used in the image forming method of the present invention will be described. Note that the present invention is not limited to the toner exemplified here.
The toner used in the image forming method of the present invention is close to the polymer suspension method, and at least a polymer having a site capable of reacting with a compound having an active hydrogen group, a polyester, a colorant, and a release agent in an organic solvent. Each toner material solution dissolved or dispersed is obtained by crosslinking and / or elongation reaction in an aqueous medium.

(Modified polyester)
The toner according to the present invention contains a modified polyester (i) as a binder resin. The modified polyester (i) refers to a state in which a bonding group other than an ester bond is present in the polyester resin, or resin components having different configurations are bonded to the polyester resin by a covalent bond, an ionic bond, or the like. Specifically, the polyester terminal is modified by introducing a functional group such as a carboxylic acid group or an isocyanate group that reacts with a hydroxyl group into the polyester terminal and further reacting with an active hydrogen-containing compound.

  Examples of the modified polyester (i) include urea-modified polyester obtained by a reaction between a polyester prepolymer (A) having an isocyanate group and amines (B). As the polyester prepolymer (A) having an isocyanate group, a polyester having a polycondensate of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC) and having an active hydrogen group is further added to a polyvalent isocyanate compound (PIC). And those reacted with. Examples of the active hydrogen group possessed by the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, and the like. Among these, an alcoholic hydroxyl group is preferable.

The urea-modified polyester is produced as follows.
Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable.
In addition, as a dihydric alcohol (DIO) and a trihydric or more polyhydric alcohol (TO), the thing similar to what was used by the said grinding | pulverization method can be used.

Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred.
In addition, as divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC), the same ones as used in the above pulverization method can be used.

The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.
In addition to the polyhydric alcohol compound (PO) and polyhydric carboxylic acid (PC) used in the above pulverization method, other polyhydric alcohol compounds (PC) may be used as long as they can form a polyester having active hydrogen groups by polycondensation It is also possible to use things.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) ); Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

  The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).

Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like.
Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine.
Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline.
Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan.
Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid.
Examples of the compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.).
Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

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

  The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

The modified polyester (i) used in the present invention is produced by a one-shot method or a prepolymer method.
The weight average molecular weight of the modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. The peak molecular weight at this time is preferably 1000 to 10000. When the molecular weight is less than 1000, the elongation reaction hardly occurs, the elasticity of the toner is small, and as a result, the resistance to hot offset deteriorates. On the other hand, when it exceeds 10,000, the problem in production becomes high in the deterioration of fixability, particle formation and pulverization.
The number average molecular weight of the modified polyester (i) is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color device are deteriorated.

  In the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B) to obtain the modified polyester (i), a reaction terminator is used as necessary to adjust the molecular weight of the resulting urea-modified polyester. be able to. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

(Unmodified polyester)
In the present invention, not only the modified polyester (i) is used alone, but also the unmodified polyester (ii) can be contained as a binder resin component together with the (i). By using (ii) in combination, the low-temperature fixability and the gloss when used in a full-color device are improved, which is preferable to the single use.

  Examples of (ii) include polycondensates of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC), which are the same as the polyester component (i), and preferred ones are also the same as (i). . Further, (ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, for example, may be modified with a urethane bond. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, the polyester component (i) and (ii) preferably have similar compositions. In the case of containing (ii), the weight ratio of (i) to (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. If the weight ratio of (i) is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight of (ii) is 1000-10000 normally, Preferably it is 2000-8000, More preferably, it is 2000-5000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. As for the acid value of (ii), 1-5 are preferable, More preferably, it is 2-4. Since a high acid value wax is used for the wax, the binder resin is easily matched with the toner used for the two-component developer because the low acid value binder resin leads to charging and high volume resistance.

  The glass transition point (Tg) of the binder resin is usually 35 to 70 ° C, preferably 55 to 65 ° C. If the temperature is lower than 35 ° C., the heat-resistant storage stability of the toner deteriorates, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the toner tends to have good heat storage stability even when the glass transition point is low as compared with known polyester-based toners.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, Yellow lead, Titanium yellow, Polyazo yellow, Oil yellow, Hansa yellow (GR, A, RN, R), Pigment yellow L, Benzidine yellow (G, GR), Permanent yellow (NCG), Vulcan fast yellow (5G, R) ), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Se Red, parachlor ortho nitro Nirin Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, Riazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalo Cyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

The colorant used in the present invention can also be used as a master batch combined with a resin.
As the binder resin to be kneaded together with the production of the masterbatch or the masterbatch, in addition to the modified and unmodified polyester resins mentioned above, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and polymers of substituted products thereof; Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α- Chloromethyl methacrylate copolymer, Tylene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid Styrene copolymers such as acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, poly Acrylic resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. The

  The master batch can be obtained by mixing and kneading the resin for the master batch and the colorant under high shearing force and kneading. At this time, an organic solvent can be used to enhance the interaction between the colorant and the resin. In addition, a so-called flushing method, which is a wet cake of a coloring agent, is a method of mixing and kneading an aqueous paste containing water of a coloring agent together with a resin and an organic solvent, transferring the coloring agent to the resin side, and removing moisture and organic solvent components. Since it can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

(Release agent)
Further, a wax may be contained together with the toner binder and the colorant. Known waxes can be used in the present invention, such as polyolefin waxes (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbons (paraffin wax, sasol wax, etc.); carbonyl group-containing waxes, etc. Can be mentioned.

  Of these, carbonyl group-containing waxes are preferred. Examples of the carbonyl group-containing wax include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18. -Octadecanediol distearate, etc.); polyalkanol esters (tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amides (ethylene diamine dibehenyl amide, etc.); polyalkylamides (trimellitic acid tristearyl amide, etc.) And dialkyl ketones (such as distearyl ketone). Among these carbonyl group-containing waxes, polyalkanoic acid esters are preferred.

  The melting point of the wax used in the present invention is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. A wax having a melting point of less than 40 ° C. has an adverse effect on heat resistant storage stability, and a wax having a melting point of more than 160 ° C. tends to cause a cold offset when fixing at a low temperature. Further, the melt viscosity of the wax is preferably 5 to 1000 cps, more preferably 10 to 100 cps as a measured value at a temperature 20 ° C. higher than the melting point. Waxes exceeding 1000 cps have poor effects for improving hot offset resistance and low-temperature fixability. The content of the wax in the toner is usually 0 to 40% by weight, preferably 3 to 30% by weight.

(Charge control agent)
The toner of the present invention may contain a charge control agent as necessary. All known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified). Quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives.

  Specifically, Nitronine-based dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E- 84, E-89 of a phenol-based condensate (manufactured by Orient Chemical Industry Co., Ltd.), TP-302 of a quaternary ammonium salt molybdenum complex, TP-415 (manufactured by Hodogaya Chemical Industry Co., Ltd.), quaternary ammonium Copy charge PSY VP2038 of salt, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (above, manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit Co., Ltd.), copper phthalocyanine, perylene, quinacridone Azo pigments, sulfonate group, carboxyl group, and polymer compounds having a functional group such as a quaternary ammonium salt.

  In the present invention, the amount of charge control agent used is determined uniquely by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents can be dissolved and dispersed after being melt-kneaded with a masterbatch and resin, and of course, they can be added directly when dissolved and dispersed in an organic solvent, or fixed on the toner surface after preparation of toner particles. May be.

(External additive)
As an external additive for assisting the fluidity, developability and chargeability of the colored particles obtained in the present invention, inorganic fine particles and hydrophobic treated inorganic fine particles can be used in combination with oxide fine particles. In the present invention, as described above, in order to improve cleaning properties, it is preferable to add at least a silica having a primary average particle size of 80 to 500 nm, but the average of primary particles subjected to a hydrophobic treatment as a main external additive It is more desirable to include at least one kind of inorganic fine particles having a particle size of 5 nm to 70 nm. Further, it is more preferable that the hydrophobized primary particles include at least one kind of inorganic fine particles having an average particle diameter of 5 nm to 20 nm and at least one kind of inorganic fine particles of 30 nm to 70 nm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g.

  Any of them can be used as long as the conditions are satisfied. For example, silica fine particles, hydrophobic silica, fatty acid metal salts (such as zinc stearate and aluminum stearate), metal oxides (such as titania, alumina, tin oxide, and antimony oxide), fluoropolymers, and the like may be contained.

  Particularly suitable additives include hydrophobized silica, titania, titanium oxide, and alumina fine particles. Silica fine particles include HDK H 2000, HDK H 2000/4, HDK H 2050EP, HVK21, HDK H 1303 (above, manufactured by Hoechst), R972, R974, RX200, RY200, R202, R805, R812 (above, Nippon Aerosil). There are). Moreover, as titania fine particles, P-25 (made by Nippon Aerosil Co., Ltd.), STT-30, STT-65C-S (above, made by Titanium Industry Co., Ltd.), TAF-140 (made by Fuji Titanium Industry Co., Ltd.), MT-150W, There are MT-500B, MT-600B, MT-150A (manufactured by Teika). In particular, as hydrophobized titanium oxide fine particles, T-805 (manufactured by Nippon Aerosil Co., Ltd.), STT-30A, STT-65S-S (above, manufactured by Titanium Industry Co., Ltd.), TAF-500T, TAF-1500T (above, Fuji Titanium Industry Co., Ltd.), MT-100S, MT-100T (above, Teika Co.), IT-S (Ishihara Sangyo Co., Ltd.) and the like.

  In order to obtain hydrophobized oxide fine particles, silica fine particles, titania fine particles, and alumina fine particles, hydrophilic fine particles are treated with a silane coupling agent such as methyltrimethoxysilane, methyltriethoxysilane, or octyltrimethoxysilane. Can be obtained. In addition, silicone oil-treated oxide fine particles and inorganic fine particles obtained by treating silicone oil with heat if necessary to treat it with inorganic fine particles are also suitable.

  Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, and amino-modified silicone. Oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, acrylic, methacryl-modified silicone oil, α-methylstyrene-modified silicone oil and the like can be used.

  Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, zinc oxide, tin oxide, quartz sand, clay, mica, and silica ash. Examples thereof include stone, diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, parium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Of these, silica and titanium dioxide are particularly preferred.

  The total amount of these external additives may be 0.5 to 6 parts by weight, preferably 1.0 to 5% by weight, based on 100 parts by weight of the toner.

  Other polymer fine particles such as polystyrene, methacrylic acid ester and acrylic acid ester copolymer obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, polycondensation system such as silicone, benzoguanamine, and nylon, thermosetting resin And polymer particles.

  Such a fluidizing agent can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .

  Examples of the cleaning property improver for removing the developer after transfer remaining on the photoreceptor or the primary transfer medium include, for example, zinc stearate, calcium stearate, fatty acid metal salts such as stearic acid, such as polymethyl methacrylate fine particles, polystyrene fine particles, etc. And polymer fine particles produced by soap-free emulsion polymerization. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

  Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.

(Toner production method)
(1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.

  The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

(2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.

  The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 2000 parts by weight, it is not economical.

Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.

  As a trade name, Surflon S-111, S-112, S-113 (above, Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (above, made by Sumitomo 3M), Unidyne DS-101, DS-102 (above, Daikin Industries, Ltd.), MegaFuck F-110, F-120, F-113, F-191, F-812, F-833 (above, Dainippon Ink Co., Ltd.) ), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (above, manufactured by Tochem Products), Footent F-100, F150 (above, Neos) Manufactured).

  Moreover, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt which has a right fluoroalkyl group is used. Salt, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage F-300 (Neos), and the like.

  As the resin fine particles, any resin can be used as long as it can form an aqueous dispersion, and it may be a thermoplastic resin or a thermosetting resin. Examples thereof include vinyl resins, polyurethane resins, epoxy resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, and polycarbonate resins. As the resin, two or more of the above resins may be used in combination.

  Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained. For example, vinyl resins are polymers obtained by homopolymerization or copolymerization of vinyl monomers, such as styrene- (meth) acrylic acid ester copolymers, styrene-butadiene copolymers, (meth) acrylic acid-acrylic acid esters. Examples thereof include resins such as a polymer, a styrene-acrylonitrile copolymer, a styrene-maleic anhydride copolymer, and a styrene- (meth) acrylic acid copolymer. The average particle diameter of the resin fine particles is 5 to 2000 nm, preferably 20 to 300 nm. In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.
This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner.
The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like. Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained.
Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

  When the toner is used as a two-component developer, the toner may be mixed with a magnetic carrier, and the carrier to toner content ratio in the developer is preferably 1 to 10 wt% as the developer.

As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 50 μm can be used.
Examples of the coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene acrylic copolymer resins, Halogenated olefin resins such as vinyl, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoro Propylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride And fluoro such as terpolymers of non-fluoride monomers including, and silicone resins.
Moreover, you may contain electrically conductive powder etc. in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.

  The toner can also be used as a one-component magnetic toner or a non-magnetic toner that does not use a carrier.

  According to the present invention, there are provided a tandem type image forming apparatus and an image forming method having at least a plurality of electrophotographic photoreceptors, charging means, exposure means, and transfer means. As a result, a good full-color image can be obtained at a very high speed as compared with the one-drum type image forming apparatus.

  Further, according to the present invention, the intermediate transfer means for primarily transferring the toner image developed on the electrophotographic photosensitive member onto the intermediate transfer member and then secondary transferring the toner image on the intermediate transfer member onto the recording material. An image forming apparatus having a plurality of color toner images sequentially superimposed on an intermediate transfer member to form a color image, and the color image is secondarily transferred onto a recording material in a batch to thereby prevent color misregistration. A suppressed and good image is provided. Further, the layout through the intermediate transfer member improves the degree of freedom of layout in the image forming apparatus, and achieves downsizing of the apparatus and improvement in maintainability.

(Development method)
In developing the latent image on the photoreceptor in the present invention, it is preferable to apply an alternating electric field.
In the developing device (700) shown in FIG. 1, during development, a vibration bias voltage obtained by superimposing an AC voltage on a DC voltage is applied to the developing sleeve (710) as a developing bias by a power source (720). The background portion potential and the image portion potential are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed in the developing portion (730). In this alternating electric field, the developer toner and carrier vibrate vigorously, and the toner flies off the developing sleeve (710) and the electrostatic binding force on the carrier and flies to the photoconductor (740) to form a latent image on the photoconductor. Correspondingly adheres.

  The difference (maximum peak voltage) between the maximum value and the minimum value of the vibration bias voltage is preferably 0.5 to 5 kV, and the frequency is preferably 1 to 10 kHz. As the waveform of the vibration bias voltage, a rectangular wave, a sine wave, a triangular wave, or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background part potential and the image part potential, but the value closer to the background part potential than the image part potential is more likely to cover the background part potential region. This is preferable for preventing toner adhesion.

  When the vibration bias voltage waveform is a rectangular wave, the duty ratio is preferably 50% or less. Here, the duty ratio is a ratio of time during which the toner is directed to the photosensitive member during one period of the vibration bias. By doing so, the difference between the peak value at which the toner is directed to the photoreceptor and the time average value of the bias can be increased, so that the movement of the toner is further activated and the potential of the latent image surface is increased. It can adhere to the distribution and improve the roughness and resolution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the photosensitive member can be reduced, the movement of the carrier is reduced, and the background portion of the latent image is reduced. The probability of carriers adhering to the substrate can be greatly reduced.

(Charging method)
As the charging device used in the image forming method of the present invention, for example, the charging device shown in FIGS. 2 and 3 can be used.

<In case of roller charging>
FIG. 2 shows a schematic configuration of an example of an image forming apparatus using a contact-type charging device. A photosensitive member (photosensitive drum) (1) as an image bearing member, which is a member to be charged, is driven to rotate at a predetermined speed (process speed) in the direction of the arrow. The charging roller (2), which is a charging member brought into contact with the photosensitive drum (1), is basically composed of a cored bar (21) and a conductive rubber layer (22) formed concentrically on the outer periphery of the cored bar. The both ends of the cored bar (21) are held freely rotating by a bearing member (not shown) and are pressed against the photosensitive drum (1) with a predetermined pressure by a pressing means (not shown). In this case, the charging roller (2) rotates following the rotational driving of the photosensitive drum (1). The charging roller (2) is formed to a diameter of 16 mm by coating a medium resistance rubber layer (22) of about 100,000 Ω · cm on a core metal (21) having a diameter of 9 mm.
The core roller (21) of the charging roller and the illustrated power source (3) are electrically connected, and a predetermined bias is applied to the charging roller by the power source. As a result, the peripheral surface of the photoreceptor is uniformly charged to a predetermined polarity and potential.

<Fur brush charging>
FIG. 3 shows a schematic configuration of an example of an image forming apparatus using a contact-type charging device. A photosensitive member (photosensitive drum) (1) as an image bearing member, which is a member to be charged, is driven to rotate at a predetermined speed (process speed) in the direction of the arrow. In this example, a brush roller (4) constituted by a fur brush is brought into contact with the photoreceptor (1) with a predetermined nip width with a predetermined pressing force against the elasticity of the brush portion.

  In this example, the fur brush roller (4) as a contact charging member is piled with a metal cored bar (41) having a diameter of 6 mm which also serves as an electrode, and conductive rayon fiber REC-B manufactured by Unitika Ltd. as a brush part. A ground tape is wound in a spiral shape to form a roll brush having an outer diameter of 14 mm and a longitudinal length of 250 mm. The brush of the brush part (42) has a density of 300 denier / 50 filaments and 155 per square millimeter. This roll brush was inserted into a pipe having an inner diameter of 12 mm while rotating in one direction, and the brush and the pipe were set to be concentric, and left in a high-temperature and high-humidity atmosphere to bend and bevel.

The resistance value of the fur brush roller (4) is 1 × 10 ⁵ Ω at an applied voltage of 100V. This resistance value was converted from the current that flows when a fur brush roller is brought into contact with a metal drum having a diameter of φ30 mm with a nip width of 3 mm and a voltage of 100 V is applied.

The resistance value of the fur brush charger is such that, even when a low-voltage defective part such as a pinhole occurs on the photosensitive member that is the object to be charged, an excessive leakage current flows into this part and the charging nip part becomes poorly charged. In order to prevent image defects, it is necessary to be 10 ⁴ Ω or more, and in order to sufficiently inject charges onto the surface of the photoreceptor, it is necessary to be 10 ⁷ Ω or less.

  Examples of the material of the brush include carbon, copper sulfide, metal, and metal oxide that have been conductively treated. By winding or pasting these around a metal or other conductive metal core, To do. In addition to REC-B manufactured by Unitika Ltd., the brush material is REC-C, REC-M1, REC-M10, SA-7 manufactured by Toray Industries, Inc., Nippon Kashiwa Co., Ltd. It can be obtained as a commercial product such as Sanderlon manufactured by Kanebo, Beltron manufactured by Kanebo, Kuraray Co., Ltd., Krabobo, carbon dispersion in rayon, or Mitsubishi Rayon Co., Ltd. global. One brush is 3 to 10 denier, and preferably has a density of 10 to 100 filaments / bundle and 80 to 600 brushes / mm. The hair foot is preferably 1 to 10 mm.

  The fur brush roller (4) is rotationally driven at a predetermined peripheral speed (surface speed) in a direction opposite to the rotation direction of the photoconductor (1) (counter), and has a speed difference with respect to the surface of the photoconductor (1). Touch. A predetermined charging voltage is applied to the fur brush roller (4) from the power source (3), so that the surface of the rotating photosensitive member is uniformly contact-charged to a predetermined polarity and potential.

  In this example, contact charging of the photosensitive member (1) by the fur brush roller (4) is performed by direct injection charging, and the surface of the rotating photosensitive member (1) is charged to the fur brush roller (4). It is charged to a potential approximately equal to the voltage.

<In case of magnetic brush charging>
In FIG. 3, the contact-type charging device is a brush roller constituted by a magnetic brush, and this brush roller is brought into contact with a predetermined nip width with a predetermined pressing force against the elasticity of the brush portion.

  As a magnetic brush as a contact charging member in this example, Zn—Cu ferrite particles having an average particle diameter of 25 μm and Zn—Cu ferrite particles having an average particle diameter of 10 μm are mixed at a weight ratio of 1: 0.05, Magnetic particles obtained by coating ferrite particles having an average particle diameter of 25 μm and having a peak at each average particle diameter position with a medium resistance resin layer were used. The contact charging member is composed of the coated magnetic particles prepared above, a nonmagnetic conductive sleeve for supporting the coated magnetic particles, and a magnet roll included therein, and the coated magnetic particles are formed on the sleeve with a thickness. Coating was performed at 1 mm to form a charging nip having a width of about 5 mm between the photosensitive member and the photosensitive member. The gap between the magnetic particle holding sleeve and the photosensitive member was about 500 μm. Further, the magnet roll is rotated so that the sleeve surface rubs in the opposite direction at twice as fast as the peripheral speed of the surface of the photoconductor, and the photoconductor and the magnetic brush are in uniform contact with each other. I did it.

  The shape of the charging member used in the present invention may take any form such as a charging roller or a fur brush in addition to the magnetic brush, and can be selected according to the specifications and form of the electrophotographic apparatus. When a charging roller is used, it is generally used by coating a medium resistance rubber layer of about 100,000 Ω · cm on a cored bar. In addition, when using a fur brush, for example, as a material of the fur brush, a fur treated with carbon, copper sulfide, metal, and metal oxide is used, and this is wound around a metal or other conductive core metal. By charging or pasting, it becomes a charger.

  In the case of using a magnetic brush, the magnetic brush is composed of various ferrite particles such as Zn—Cu ferrite as a charging member, a non-magnetic conductive sleeve for supporting it, and a magnet roll included therein.

  The shape of the charging member used in the present invention is not limited to the above-described charging roller, fur brush roller, and magnetic brush roller, and may take any form and is selected according to the specifications and form of the electrophotographic apparatus. Is possible.

(Process cartridge)
The developer of the present invention can be used in an image forming apparatus having a process cartridge as shown in FIG.
In the present invention, a plurality of components such as the above-described photosensitive member, charging unit, developing unit, and cleaning unit are integrally combined as a process cartridge. It is configured to be detachable from the image forming apparatus main body.

  The process cartridge (1) shown in FIG. 4 includes a photoreceptor (11), a charging unit (12), a developing unit (13), and a cleaning unit (14). In operation, the photosensitive member (11) is rotationally driven at a predetermined peripheral speed. In the rotating process, the photosensitive member (11) is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the charging means (12), and then image exposure from image exposure means such as slit exposure or laser beam scanning exposure is performed. The electrostatic latent image is sequentially formed on the peripheral surface of the photoreceptor (11) in this way, and the formed electrostatic latent image is then developed with toner by the developing means (13), and the developed toner image is The transfer unit sequentially transfers the transfer material fed from the sheet feeding unit between the photoconductor and the transfer unit in synchronization with the rotation of the photoconductor. The transfer material that has received the image transfer is separated from the surface of the photoreceptor (11), introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor (11) after the image transfer is cleaned by removing the transfer residual toner by the cleaning means (14), and after being further discharged, it is repeatedly used for image formation.

(Fixing device)
As the fixing device used in the image forming method of the present invention, for example, a charging device shown in FIG. 5 can be used.
The fixing device shown in FIG. 5 includes a heating roller (1) heated by electromagnetic induction of induction heating means (6), a fixing roller (2) (opposite rotating body) arranged in parallel with the heating roller (1), and the like. An endless belt-like heat-resistant belt that is stretched between the heating roller (1) and the fixing roller (2), is heated by the heating roller (1), and is rotated in the direction of arrow A by the rotation of at least one of these rollers. (Toner heating medium) (3) and a pressure roller (4) (pressure rotator) which is pressed against the fixing roller (2) via the belt (3) and rotates in the forward direction with respect to the belt (3) ).

  The heating roller (1) is made of a hollow cylindrical magnetic metal member such as iron, cobalt, nickel or an alloy of these metals, and has an outer diameter of 20 to 40 mm and a thickness of 0.3 to 1.0 mm, for example. It has a low heat capacity and quick temperature rise.

  The fixing roller (2) (opposing rotating body) is made of, for example, a metal core (2a) made of stainless steel or the like, and a heat-resistant silicone rubber that is solid or foamed and covered with the core (2a). It consists of a member (2b). In order to form a contact portion having a predetermined width between the pressure roller (4) and the fixing roller (2) by the pressing force from the pressure roller (4), the outer shape is set to about 20 to 40 mm. 1) It is larger. The elastic member (2b) has a thickness of about 4 to 6 mm. With this configuration, since the heat capacity of the heating roller (1) is smaller than the heat capacity of the fixing roller (2), the heating roller (1) is rapidly heated and the warm-up time is shortened.

  The belt (3) stretched between the heating roller (1) and the fixing roller (2) is heated at the contact portion (W1) with the heating roller (1) heated by the induction heating means (6). Then, the inner surface of the belt (3) is continuously heated by the rotation of the rollers (1) and (2). As a result, the entire belt is heated.

FIG. 6 shows the configuration of the belt (3). The configuration of the belt (3) is as follows.
The following four layers are formed from the inner layer to the surface layer.
・ Substrate (resin layer: polyimide (PI) resin, etc.)
・ Heat generation layer (Ni, Ag, SUS, etc. as conductive material): (3a)
・ Intermediate layer (Aiming for uniform fixing with an elastic layer): (3b)
・ Surface layer (release layer) (Aimed at release effect and oilless with fluororesin material): (3c)

  The thickness of the release layer (3c) is preferably about 10 μm to 300 μm, particularly about 200 μm. In this way, the toner image (T) formed on the transfer material (11) is sufficiently wrapped by the surface layer of the belt (3), so that the toner image (T) can be uniformly heated and melted. Become.

  The thickness of the release layer (3c), that is, the surface release layer, is required to be at least 10 μm in order to ensure wear resistance over time. On the other hand, when the thickness of the release layer (3c) is larger than 300 μm, the heat capacity of the belt (3) increases and the time required for warm-up becomes longer. In addition, in the toner fixing process, the belt surface temperature is difficult to decrease, the agglomeration effect of the melted toner at the fixing portion outlet cannot be obtained, the belt releasability is reduced, and the toner adheres to the belt. Hot offset occurs.

  As the base material of the belt (3), heat resistance such as fluorine resin, polyimide resin, polyamide resin, polyamideimide resin, PEEK resin, PES resin, PPS resin, etc., instead of the heat generating layer (3a) made of the above metal. You may use the resin layer which has.

  The pressure roller (4) includes, for example, a metal core (4a) made of a metal cylindrical member having high thermal conductivity such as copper or aluminum, and heat resistance and toner separation provided on the surface of the metal core (4a). It is comprised from the highly elastic elastic member (4b). In addition to the above metal, SUS may be used for the core metal (4a). The pressure roller (4) presses the fixing roller (2) via the belt (3) to form a fixing nip (N). In this embodiment, the hardness of the pressure roller (4) Is made harder than the fixing roller (2), so that the pressure roller (4) bites into the fixing roller (2) (and the belt (3)), and the recording material (11) is pressed by this biting. Since the roller (4) has a circumferential shape on the surface, the recording material (11) is easily separated from the surface of the belt (3). The outer diameter of the pressure roller (4) is about 20 to 40 mm, which is the same as that of the fixing roller (2), but the wall pressure is about 0.5 to 2.0 mm and is thinner than the fixing roller (2).

  As shown in FIG. 5, the induction heating means (6) for heating the heating roller (1) by electromagnetic induction includes an excitation coil (7) as a magnetic field generation means and a coil around which the excitation coil (7) is wound. And a guide plate (8). The coil guide plate (8) has a semi-cylindrical shape disposed close to the outer peripheral surface of the heating roller (1), and the excitation coil (7) has a single long excitation coil wire as the coil guide plate (8). Along the axial direction of the heating roller (1). The exciting coil (7) has an oscillation circuit connected to a drive power supply (not shown) whose frequency is variable.

  On the outside of the exciting coil (7), a semi-cylindrical exciting coil core (9) made of a ferromagnetic material such as ferrite is fixed to the exciting coil core support member (10) and is arranged close to the exciting coil (7). Yes.

(Image forming device)
For example, the image forming apparatus shown in FIGS. 7 and 8 can be used as the image forming apparatus in which the image forming method of the present invention is implemented.

  In FIG. 7, a main body (100) includes an image writing unit (120Bk, 120C, 120M, 120Y), an image forming unit (130Bk, 130C, 130M, 130Y) and a paper feeding unit for performing color image formation by electrophotography. (140). Based on the image signal, image processing is performed by an image processing unit (not shown) and converted into black (Bk), cyan (C), magenta (M), and yellow (Y) color signals for image formation, It transmits to an image writing part (120Bk, 120C, 120M, 120Y). The image writing unit (120Bk, 120C, 120M, 120Y) is a laser scanning optical system including, for example, a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group (none of which are shown). There are four writing optical paths corresponding to the respective color signals, and image writing corresponding to the respective color signals is performed in the image forming units (130Bk, 130C, 130M, and 130Y).

  The image forming unit (130Bk, 130C, 130M, and 130Y) includes photoconductors (210Bk, 210C, 210M, and 210Y) for black, cyan, magenta, and yellow, and the photoconductors (210Bk, 210C, and 210Y) for these colors. 210M and 210Y) are usually OPC photoreceptors. Around each photoconductor (210Bk, 210C, 210M, 210Y), there is a charging device (215Bk, 215C, 215M, 215Y), an exposure unit for laser light from the image writing unit (120Bk, 120C, 120M, 120Y). , Developing devices for each color (200Bk, 200C, 200M, 200Y), primary transfer devices (230Bk, 230C, 230M, 230Y), cleaning devices (300Bk, 300C, 300M, 300Y), static eliminators (not shown), etc. Is arranged. The developing device (200Bk, 200C, 200M, 200Y) uses a two-component magnetic brush developing system. An intermediate transfer belt (220) is interposed between each photoconductor (210Bk, 210C, 210M, 210Y) and the primary transfer device (230Bk, 230C, 230M, 230Y), and this intermediate transfer belt (220). The toner images of the respective colors are sequentially transferred from the respective photoconductors so as to carry the toner images on the respective photoconductors.

  In some cases, a pre-transfer charger (502) as pre-transfer charging means is disposed outside the intermediate transfer belt (220) at a position after passing the primary transfer position of the final color and before passing the secondary transfer position. It is preferable. The pre-transfer charger (502) transfers the toner image before transferring the toner image on the intermediate transfer belt (220) transferred to the photosensitive member (210) in the primary transfer portion onto a transfer sheet as a transfer material. The toner image is uniformly charged to the same polarity as the toner image.

  The toner image on the intermediate transfer belt (220) transferred from each photoconductor (210Bk, 210C, 210M, 210Y) includes a halftone portion and a solid portion, or includes portions having different amounts of toner overlap. Therefore, the charge amount may vary. Further, when the discharge amount generated in the gap adjacent to the downstream side of the primary transfer portion in the movement direction of the intermediate transfer belt causes variation in charge amount in the toner image on the intermediate transfer belt (220) after the primary transfer. There is also. Such variation in the charge amount in the same toner image lowers the transfer margin in the secondary transfer portion that transfers the toner image on the intermediate transfer belt (220) onto the transfer paper. Therefore, the toner image before being transferred onto the transfer paper by the pre-transfer charger (502) is uniformly charged to the same polarity as the toner image, thereby eliminating the variation in the charge amount in the same toner image. Improving the transfer margin.

  As described above, according to the present embodiment, the toner image on the intermediate transfer belt (220) transferred from each photoconductor (210Bk, 210C, 210M, 210Y) is uniformly charged by the pre-transfer charger (502), so that intermediate Even if there is a variation in the charge amount in the toner image on the transfer belt (220), the transfer characteristics in the secondary transfer portion can be made substantially constant across the portions of the toner image on the intermediate transfer belt (220). it can. Therefore, it is possible to suppress a decrease in transfer margin when transferring to transfer paper and to stably transfer a toner image.

  In the above-described embodiment, the amount of charge charged by the pre-transfer charger (502) varies depending on the moving speed of the intermediate transfer belt (220) that is an object to be charged. For example, if the moving speed of the intermediate transfer belt (220) is slow, the time during which the same portion of the toner image on the intermediate transfer belt (220) passes through the charging region by the pre-transfer charger (502) becomes longer, so growing. Conversely, when the moving speed of the intermediate transfer belt (220) is fast, the charge amount of the toner image on the intermediate transfer belt (220) becomes small. Accordingly, when the moving speed of the intermediate transfer belt (220) changes while the toner image on the intermediate transfer belt (220) passes through the charging position by the pre-transfer charger (502), the intermediate transfer is performed. It is desirable to control the pre-transfer charger (502) according to the moving speed of the belt (220) so that the charge amount with respect to the toner image does not change midway.

  The pre-transfer charger (502) surrounds the discharge wire (502a), the grid electrode (502b) interposed between the discharge wire (502a) and the intermediate transfer belt (220), and the discharge wire (502a). And a DC high voltage having the same polarity as the charging polarity of the toner image on the intermediate transfer belt (220) to the discharge wire (502a) by the power source (803) for the pre-transfer charger (502). Is applied and corona discharge occurs.

  Conductive rollers (241), (242), and (243) are provided between the primary transfer devices (230Bk, 230C, 230M, and 230Y). After the transfer paper is fed from the paper feed unit (140), it is carried on the transfer belt (500) via the registration roller pair (160), and the intermediate transfer belt (220) and the transfer belt (500) are in contact with each other. The toner image on the intermediate transfer belt (220) is transferred to the transfer paper by the secondary transfer roller (600), and a color image is formed.

  Then, the transfer paper after the image formation is conveyed to the fixing device (150) by the transfer belt (500), and the image is fixed to obtain a color image. The toner on the intermediate transfer belt (220) remaining without being transferred is removed from the belt by the intermediate transfer belt cleaning device (260).

  Since the toner polarity on the intermediate transfer belt (220) before transfer onto the transfer paper is the same negative polarity as that during development, a positive transfer bias voltage is applied to the secondary transfer roller (600), and the toner is transferred. It is transferred onto paper. The nip pressure at this portion affects the transfer property and greatly affects the fixability. Further, the toner on the intermediate transfer belt (220) remaining without being transferred is discharged and charged to the positive polarity side and charged from 0 to the positive side at the moment when the transfer paper and the intermediate transfer belt (220) are separated. Note that the toner image formed when the transfer paper is jammed or in the non-image area is not affected by the secondary transfer, and of course remains in the negative polarity.

  The thickness of the photosensitive layer is 30 μm, the beam spot diameter of the optical system is 50 × 60 μm, and the light quantity is 0.47 mW. The developing process is performed with the charging (exposure side) potential V0 of the photoreceptor (black) (210Bk) being −700 V, the post-exposure potential VL being −120 V, the developing bias voltage being −470 V, that is, the developing potential 350 V. The visible image of the toner (black) formed on the photoconductor (black) (210Bk) is then transferred (intermediate transfer belt and transfer paper) and completed as an image through a fixing process. First, all the colors are transferred from the primary transfer device (230Bk, 230C, 230M, 230Y) to the intermediate transfer belt (220), and then transferred to the transfer paper by applying a bias to another secondary transfer roller (600). Transcribed.

Next, the photoconductor cleaning device will be described in detail.
In FIG. 7, each developing device (200Bk, 200C, 200M, 200Y) and each cleaning device (300Bk, 300C, 300M, 300Y) are connected to each other by a toner transfer pipe (250Bk, 250C, 250M, 250Y). (Dashed line in FIG. 6). Each toner transfer pipe (250Bk, 250C, 250M, 250Y) contains a screw (not shown), and the toner collected by each cleaning device (300Bk, 300C, 300M, 300Y) Each developing device (200Bk, 200C, 200M, 200Y) is transferred.

  In the conventional direct transfer method using a combination of the four photosensitive drums and the belt conveyance, paper dust adheres due to contact between the photosensitive member and the transfer paper, and the toner is collected when toner is collected. The image was deteriorated such as toner missing and could not be used. Furthermore, in the conventional system combining a single photoconductor drum and intermediate transfer, the use of an intermediate transfer member eliminates paper dust adhesion to the photoconductor during transfer paper transfer, but recycling of residual toner on the photoconductor In practice, it is practically impossible to separate the mixed color toners. There is also a proposal to use a mixed color toner as a black toner, but even if all the colors are mixed, it does not become black, and the color changes depending on the print mode. Therefore, it is impossible to recycle the toner with one photoconductor configuration.

  On the other hand, in the printer according to the present embodiment, the intermediate transfer belt (220) is used, so that paper dust is less mixed and paper dust is prevented from adhering to the intermediate transfer belt (220) during paper transfer. Is done. Since each photoconductor (210Bk, 210C, 210M, 210Y) uses independent color toner, it is not necessary to contact or separate each photoconductor cleaning device (300Bk, 300C, 300M, 300Y), and only the toner is reliably collected. can do.

  The positively charged toner remaining on the intermediate transfer belt (220) is cleaned by a conductive fur brush (262) to which a negative voltage is applied. The method of applying a voltage to the conductive fur brush (262) is exactly the same as that of the conductive fur brush (261) except for the polarity. The toner remaining without being transferred is also almost cleaned by the two conductive fur brushes (261) and (262). Here, toner, paper powder, talc, and the like remaining without being cleaned by the conductive fur brush (262) are negatively charged by the negative voltage of the conductive fur brush (262). The next black primary transfer is a transfer using a positive voltage, and negatively charged toner or the like is attracted to the intermediate transfer belt (220) side, so that the transfer to the photoconductor (black) (210Bk) side can be prevented.

  Next, the intermediate transfer belt (220) used in the image forming apparatus of this embodiment will be described. As described above, the intermediate transfer belt is preferably a single resin layer, but may have an elastic layer or a surface layer as necessary.

  As the resin material constituting the resin layer, polycarbonate, fluororesin (ETFE, PVDF), polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene -Vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer) Styrene-octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene- (Methacrylic acid phenyl copolymer, etc.), styrene -Styrenic resins (monopolymer or copolymer containing styrene or a styrene-substituted product) such as methyl α-chloroacrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, methyl methacrylate resin, methacrylic acid Butyl resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (silicone modified acrylic resin, vinyl chloride resin modified acrylic resin, acrylic / urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, vinyl chloride -Vinyl acetate copolymer, rosin modified maleic acid resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene, polybutadiene, polyvinylidene chloride, ionomer resin, polyurethane resin, silicone resin , Ketone resin, ethylene - ethyl acrylate copolymer, may be used xylene resin and polyvinyl butyral resin, polyamide resin, one kind or two kinds or more selected from the group consisting of modified polyphenylene oxide resin. However, it is a matter of course that the material is not limited to the above materials.

  Examples of the elastic material (elastic material rubber, elastomer) constituting the elastic layer include butyl rubber, fluorine-based rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber natural rubber, isoprene rubber, styrene-butadiene rubber, Butadiene rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin rubber, ricone rubber, fluororubber, Polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber, thermoplastic elastomer (eg polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyamide, polyurea, polyester) It is possible to use one kind or two kinds or more selected from the group consisting of fluorocarbon resin) or the like. However, it is a matter of course that the material is not limited to the above materials.

  The material for the surface layer is not particularly limited, but a material that reduces the adhesive force of the toner to the surface of the intermediate transfer belt and increases the secondary transfer property is required. For example, materials that use one or more of polyurethane, polyester, epoxy resin, etc. to reduce surface energy and increase lubricity, such as fluorine resin, fluorine compound, fluorocarbon, titanium dioxide, silicon carbide, etc. One kind or two or more kinds of powders and particles or particles having different particle diameters can be dispersed and used. Further, it is also possible to use a material having a surface energy reduced by forming a fluorine-rich layer on the surface by heat treatment, such as a fluorine-based rubber material.

  A resistance value adjusting conductive agent is added to the resin layer and the elastic layer. The conductive agent for adjusting the resistance value is not particularly limited. For example, carbon black, graphite, metal powder such as aluminum and nickel, tin oxide, titanium oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide Conductive metal oxides such as composite oxide (ATO) and indium oxide-tin oxide composite oxide (ITO), and conductive metal oxide covered with insulating fine particles such as barium sulfate, magnesium silicate, and calcium carbonate. It may be a thing. Of course, the conductive agent is not limited thereto.

  FIG. 8 shows another example of an image forming apparatus in which the image forming method of the present invention is implemented, and is a tandem indirect transfer type electrophotographic apparatus. In the figure, (100) is a copying apparatus main body, (200) is a paper feed table on which it is placed, (300) is a scanner mounted on the copying apparatus main body (100), and (400) is an automatic document feeder mounted thereon. (ADF). The copying machine main body (100) is provided with an endless belt-shaped intermediate transfer member (10) in the center.

As shown in FIG. 8, the intermediate transfer member (10) is wound around three support rollers (14), (15), and (16) in the illustrated example so that it can be rotated and conveyed clockwise in the drawing.
In this illustrated example, an intermediate transfer body cleaning device (17) for removing residual toner remaining on the intermediate transfer body (10) after image transfer is provided on the left of the second support roller (15) among the three.

  Further, among the three, the intermediate transfer member (10) stretched between the first support roller (14) and the second support roller (15) has yellow, cyan and magenta along the transport direction. The four black image forming means (18) are arranged side by side to constitute a tandem image forming apparatus (20).

  On the tandem image forming apparatus (20), an exposure apparatus (21) is further provided as shown in FIG. On the other hand, a secondary transfer device (22) is provided on the side opposite to the tandem image forming device (20) with the intermediate transfer member (10) interposed therebetween. In the illustrated example, the secondary transfer device (22) includes a secondary transfer belt (24), which is an endless belt, spanned between two rollers (23), and the second transfer device (22) passes through an intermediate transfer member (10). 3 is pressed against the support roller (16), and the image on the intermediate transfer body (10) is transferred to the sheet.

  Next to the secondary transfer device (22), a fixing device (25) for fixing the transferred image on the sheet is provided. The fixing device (25) is configured by pressing a pressure roller (27) against a fixing belt (26) which is an endless belt.

  The secondary transfer device (22) described above is also provided with a sheet transport function for transporting the image-transferred sheet to the fixing device (25). Of course, as the secondary transfer device (22), a transfer roller or a non-contact charger may be arranged, but in such a case, it is difficult to provide this sheet conveyance function together.

  In the illustrated example, a sheet is placed under such a secondary transfer device (22) and a fixing device (25) so as to record an image on both sides of the sheet in parallel with the tandem image forming device (20). A sheet inverting device (28) for inverting is provided.

  Now, when making a copy using this color electrophotographic apparatus, the document is set on the document table (30) of the automatic document feeder (400). Alternatively, the automatic document feeder (400) is opened, a document is set on the contact glass (32) of the scanner (300), and the automatic document feeder (400) is closed and pressed by it.

  When a start switch (not shown) is pressed, when the document is set on the automatic document feeder (400), the document is transported and moved onto the contact glass (32), and then the other contact glass (32). When a document is set on the scanner, the scanner (300) is immediately driven to travel on the first traveling body (33) and the second traveling body (34). Then, the first traveling body (33) emits light from the light source, and the reflected light from the document surface is further reflected toward the second traveling body (34) and reflected by the mirror of the second traveling body (34). Then, the image is placed in the reading sensor (36) through the imaging lens (35) and the content of the original is read.

  When a start switch (not shown) is pressed, one of the support rollers (14), (15), and (16) is driven to rotate by the drive motor (not shown), and the other two support rollers are driven to rotate. The transfer body (10) is rotated and conveyed. At the same time, the individual image forming means (18) rotates the photoreceptor (40) to form monochrome images of black, yellow, magenta, and cyan on each photoreceptor (40). Then, along with the conveyance of the intermediate transfer member (10), these monochrome images are sequentially transferred to form a composite color image on the intermediate transfer member (10).

  On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers (42) of the paper feed table (200) is selectively rotated, and one of paper feed cassettes (44) provided in multiple stages in the paper bank (43). The sheet is fed out from the sheet, separated one by one by a separation roller (45), put into a sheet feeding path (46), and conveyed by a conveying roller (47) to a sheet feeding path (48) in the copying machine main body (100). Guide and stop against the registration roller (49).

  Alternatively, the sheet feeding roller (50) is rotated to feed out the sheets on the manual feed tray (51), separated one by one by the separation roller (52), and placed in the manual sheet feeding path (53). ) And stop.

  Then, the registration roller (49) is rotated in time with the composite color image on the intermediate transfer member (10), and the sheet is fed between the intermediate transfer member (10) and the secondary transfer device (22). The image is transferred by the next transfer device (22) and a color image is recorded on the sheet.

  The sheet after the image transfer is conveyed by the secondary transfer device (22) and sent to the fixing device (25). The fixing device (25) applies heat and pressure to fix the transferred image, and then the switching claw. It is switched at (55), discharged by the discharge roller (56), and stacked on the discharge tray (57). Alternatively, it is switched by the switching claw (55) and put into the sheet reversing device (28), where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then the paper discharge tray (56) is discharged by the discharge roller (56). 57) Drain up.

  On the other hand, the intermediate transfer member (10) after the image transfer is removed by the intermediate transfer member cleaning device (17) to remove residual toner remaining on the intermediate transfer member (10) after the image transfer, and the tandem image forming device (20). To prepare for image formation again.

  Here, the registration roller (49) is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.

  The measuring methods of Tg (glass transition temperature), melting point, hydroxyl value, acid value, weight average molecular weight, and number average molecular weight described in Examples and Comparative Examples below are as follows.

(Measurement method of Tg)
Measure using a differential scanning calorimeter. Specifically, the measurement was performed under the following measurement conditions using TA-60WS and DSC-60 manufactured by Shimadzu Corporation according to the following procedure.
〔Measurement condition〕
Sample container: Aluminum sample pan (with lid)
Sample amount: 5mg
Reference: Aluminum sample pan (alumina 10mg)
Atmosphere: Nitrogen (flow rate 50ml / min)
(Temperature conditions)
Starting temperature: 20 ° C
Temperature increase rate: 10 ° C / min
End temperature: 150 ° C
Retention time: None
Temperature drop: 10 ° C / min
End temperature: 20 ° C
Retention time: None
Temperature increase rate: 10 ° C / min
End temperature: 150 ° C
The measurement results were analyzed using the data analysis software (Ta-60, version 1.52) manufactured by Shimadzu Corporation. The analysis method specifies a range of ± 5 ° C centering on the point showing the maximum peak on the lowest temperature side of the DrDSC curve which is the DSC differential curve of the second temperature rise, and the peak temperature is determined using the peak analysis function of the analysis software. Ask. Next, the maximum endothermic temperature of the DSC curve is obtained using the peak analysis function of the analysis software in the range of the peak temperature + 5 ° C. and −5 ° C. in the DSC curve. The temperature shown here corresponds to the glass transition temperature (Tg) of the toner.

(Measuring method of melting point)
A TG-DSC system TAS-100 manufactured by Rigaku Corporation was used to measure the melting point of the ionic organic compound. First, about 10 mg of a sample is placed in an aluminum sample container, which is placed on a holder unit and set in an electric furnace. Heat from room temperature to 180 ° C. at a heating rate of 10 ° C./min. The melting point was calculated from the contact point between the tangent line of the endothermic curve near the melting point and the base line using the analysis system in the TAS-100 system.

(Measurement method of hydroxyl value)
0.5 g of the sample was precisely weighed into a 100 ml volumetric flask, and 5 ml of an acetylating reagent was correctly added thereto. Then, it was heated by being immersed in a bath at 100 ° C. ± 5 ° C. After 1 to 2 hours, the flask was taken out of the bath, allowed to cool, then added with water and shaken to decompose acetic anhydride. Next, in order to complete the decomposition, the flask was again heated in a bath for 10 minutes or more and allowed to cool, and then the wall of the flask was thoroughly washed with an organic solvent. This solution was subjected to potentiometric titration with an N / 2 potassium hydroxide ethyl alcohol solution using the electrode to determine the hydroxyl value (according to JIS K0070-1966).

(Measurement method of acid value)
Weigh accurately 1 to 1.5 g of wax in an Erlenmeyer flask, add 20 ml of xylene, and dissolve with heating. After dissolution, 20 ml of dioxane is added and titrated as soon as possible with 1/10 phenolphthalein solution with N / 10 potassium hydroxide standard methanol solution while the liquid does not become cloudy or hazy. At the same time, perform a blank test.
The calculation formula is as shown in Formula 1 below.

(Equation 1) Formula 1
Acid value = [5.61 × (AB) × f] / S
However,
A: ml of N / 10 potassium hydroxide standard methanol solution required for this test
B: Number of ml of N / 10 potassium hydroxide standard methanol solution required for the blank test
f: Factor of N / 10 potassium hydroxide standard methanol solution
S: Sample (g)

(Measurement method of weight average molecular weight)
The mass average molecular weight of the polyester resin was measured by GPC (gel permeation chromatography) under the following conditions.
・ Apparatus: GPC-150C (manufactured by Waters)
Column: KF801-807 (manufactured by Shodex)
・ Temperature: 40 ℃
・ Solvent: THF (tetrahydrofuran)
・ Flow rate: 1.0 mL / min
Sample: 0.1 mL of a sample having a concentration of 0.05 to 0.6% was injected.
From the molecular weight distribution of the polyester resin measured under the above conditions, the weight average molecular weight of the polyester resin was calculated using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

(Measurement method of number average molecular weight)
The number average molecular weight was measured using GPC-150C (manufactured by Waters) and columns KF801 to 807 (manufactured by Shodex). At this time, THF (tetrahydrofuran) was used as a solvent, and measurement was performed at a temperature of 40 ° C. and a flow rate of 1.0 ml / min. As a sample, 0.05 ml to 0.6% by weight of a resin solution was used and 0.1 ml was injected. Further, when the insoluble content when adding 1 g of resin to 100 ml of THF was 75% by weight or more, DMF (dimethylformamide) was used as a solvent. The number average molecular weight was calculated from a molecular weight calibration curve prepared using a monodisperse polystyrene standard sample.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In addition, this invention is not limited to the Example and comparative example which are illustrated here. In addition, the part in an Example represents a weight part.

<Toner>
First, a specific production example of the toner used for evaluation will be described. The toner used in the present invention is not limited to these examples.

[Toner 1]
~ Synthesis of organic fine particle emulsion ~
In a reaction vessel equipped with a stir bar and a thermometer, 683 parts of water, 11 parts of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries), 166 parts of methacrylic acid, 110 butyl acrylate Parts and 1 part of ammonium persulfate were added and stirred at 3800 rpm for 30 minutes to obtain a white emulsion. The system was heated to raise the system temperature to 75 ° C. and reacted for 4 hours. Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 6 hours, and an aqueous dispersion of vinyl resin (methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate sodium salt copolymer). [Fine particle dispersion 1] was obtained. The volume average particle diameter of [fine particle dispersion 1] measured by LA-920 was 110 nm. A portion of [Fine Particle Dispersion 1] was dried to isolate the resin component. The Tg of the resin was 58 ° C., and the weight average molecular weight was 130,000.

~ Preparation of aqueous phase ~
990 parts of water, 83 parts of [fine particle dispersion 1], 37 parts of a 48.3% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7: manufactured by Sanyo Chemical Industries) and 90 parts of ethyl acetate are mixed and stirred. A milky white liquid was obtained. This is designated as [Aqueous Phase 1].

-Preparation of aqueous solution of fluorinated activator-
N, N, N-trimethyl- [3- (4-perfluorononenyloxybenzamido) propyl] ammonium, Iodide Product name 10-Factant 310 (manufactured by Neos) and 297 parts of methanol are placed in a container and heated to 50 ° C. And stir until clear. The obtained fluorine-based activator methanol solution was added dropwise to 693 parts of stirred ion-exchanged water, and stirred at 50 ° C. for 30 minutes after completion of the addition to obtain [Fluorine-based activator aqueous solution 1].

~ Synthesis of low molecular weight polyester ~
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen inlet tube, 229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propylene oxide 3-mole adduct, 208 parts terephthalic acid, 46 parts adipic acid and dibutyl 2 parts of tin oxide was added, reacted at 230 ° C. for 7 hours at normal pressure, and further reacted for 5 hours at a reduced pressure of 10 to 15 mmHg. Then 44 parts of trimellitic anhydride was added to the reaction vessel, and 3 parts at 180 ° C. and normal pressure. By reacting for a time, [low molecular weight polyester 1] was obtained. [Low molecular polyester 1] had a number average molecular weight of 2,300, a weight average molecular weight of 6,700, Tg of 43 ° C., and an acid value of 25.

~ Synthesis of intermediate polyester ~
In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, 682 parts of bisphenol A ethylene oxide 2-mole adduct, 81 parts of bisphenol A propylene oxide 2-mole adduct, 283 parts of terephthalic acid, trimellitic anhydride 22 And 2 parts of dibutyltin oxide were added, reacted at 230 ° C. for 7 hours at normal pressure, and further reacted for 5 hours at a reduced pressure of 10 to 15 mmHg to obtain [Intermediate Polyester 1]. [Intermediate Polyester 1] had a number average molecular weight of 2200, a weight average molecular weight of 9700, Tg of 54 ° C., an acid value of 0.5, and a hydroxyl value of 52.

  Next, 410 parts of [Intermediate polyester 1], 89 parts of isophorone diisocyanate and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. Polymer 1] was obtained. [Prepolymer 1] had a free isocyanate weight percentage of 1.53%.

~ Synthesis of ketimine ~
In a reaction vessel equipped with a stirrer and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 4 and a half hours to obtain [ketimine compound 1]. The amine value of [ketimine compound 1] was 417.

~ Synthesis of master batch (MB) ~
1200 parts of water, 540 parts of carbon black (made by Printex 35 Dexa) [DBP oil absorption = 42 ml / 100 mg, pH = 9.5] and 1200 parts of polyester resin are added and mixed with a Henschel mixer (made by Mitsui Mining Co., Ltd.). The mixture was kneaded at 130 ° C. for 1 hour using two rolls, rolled and cooled, and pulverized with a pulverizer to obtain [Masterbatch 1].

~ Preparation of oil phase ~
In a container in which a stir bar and a thermometer were set, 378 parts of [Low molecular weight polyester 1], Carnauba WAX10O part, 947 parts of ethyl acetate were charged, heated to 80 ° C. with stirring, and kept at 80 ° C. for 5 hours. Cooled to 30 ° C. in 1 hour. Next, 500 parts of [Masterbatch 1] and 500 parts of ethyl acetate were placed in a container and mixed for 1 hour to obtain [Raw material solution 1].

  [Raw Material Solution 1] 1324 parts are transferred to a container, and using a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), liquid feeding speed is 1 kg / hr, disk peripheral speed is 6 m / sec, and 0.5% zirconia beads are 80% by volume. Carbon black and WAX were dispersed under conditions of filling and 3 passes. Next, 1324 parts of a 65% ethyl acetate solution of [low molecular weight polyester 1] was added, followed by two passes with a bead mill under the above conditions to obtain [Pigment / WAX Dispersion 1]. The solid content concentration of [Pigment / WAX Dispersion 1] (130 ° C., 30 minutes) was 50%.

~ Emulsification-Desolvation ~
[Pigment / WAX Dispersion 1] 749 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container, TK homomixer (manufactured by Tokushu Kika) at 5,000 rpm for 2 minutes After mixing, 1200 parts of [Aqueous Phase 1] was added to the container and mixed with a TK homomixer at 13,000 rpm for 25 minutes to obtain [Emulsified Slurry 1].

  [Emulsion slurry 1] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C for 8 hours, aging was carried out at 45 ° C for 7 hours to obtain [Dispersion slurry 1].

~ Cleaning-Fluorine activator treatment-Drying-Air sieve ~
[Dispersion Slurry 1] After filtering 100 parts under reduced pressure,
(1): 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
(2): 100 parts of a 10% aqueous sodium hydroxide solution was added to the filter cake of (1), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure.
(3): 100 parts of 10% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer (10 minutes at 12,000 rpm) and filtered.
(4): 300 parts of ion-exchanged water is added to the filter cake of (3), mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered twice to obtain [filter cake 1]. It was.
(5): 630 parts of [filter cake 1] and 2928 parts of ion-exchanged water are placed in a container, stirred with a three-one motor (manufactured by Shinto Kagaku) (rotation number: 5 minutes at 400 rpm), and heated to 30 ° C. While maintaining the rotation speed and temperature, 11 parts of [Fluoroactive aqueous solution 1] is dropped. It stirred for 60 minutes after completion | finish of dripping, and filtered, and obtained the filter cake 1 after a fluorine-type activator process.

  [Filter cake 1 after treatment with fluorine-based activator] was dried at 45 ° C. for 48 hours in a circulating drier. Then, it was sieved with a mesh having a mesh size of 75 μm to obtain a toner base.

  To 100 parts by weight of the toner base, 0.5 parts of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 15 nm and 0.6 parts of titanium oxide fine powder (isobutyltrimethoxysilane treatment) having an average particle diameter of 15 nm are used. And 0.6 part of silica fine powder having an average particle size of 140 nm (hexamethyldisilazane treatment), followed by external addition treatment using Henschel 20C (Mitsui Mining Co., Ltd.) and mixing at a rotational speed of 2390 rpm for 7 minutes. [Toner 1] was produced by removing the fluid.

[Toner 2]
In [Toner 1], [Toner 2] was prepared by changing the external addition time from 7 minutes to 5 minutes.

[Toner 3]
In [Toner 1], [Toner 3] was produced by changing the rotation speed of the external addition process from 2390 rpm to 2010 rpm and the time from 7 minutes to 4 minutes.

[Toner 4]
A toner was prepared in the same manner as in [Toner 3] except that the steps of ~ emulsification-desolvation ~ were changed as follows.
To 100 parts of the obtained toner base, 0.5 parts of silica fine powder (hexamethyldisilazane treatment) with an average particle diameter of 15 nm and titanium oxide fine powder (isobutyltrimethoxysilane treatment) with an average particle diameter of 15 nm are 0.6. And 2.0 parts of silica fine powder having an average particle size of 140 nm (hexamethyldisilazane treatment) are added and mixed for 4 minutes at a rotation speed of 2010 rpm using Henschel 20C (Mitsui Mine). Then, the toner was sieved to prepare [Toner 4].

~ Emulsification-Desolvation ~
[Pigment / WAX Dispersion 1] 749 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container, TK homomixer (manufactured by Tokushu Kika) at 5,000 rpm for 2 minutes After mixing, 1200 parts of [Aqueous phase 1] was added to the container, and mixed with a TK homomixer at 13,000 rpm for 20 minutes to obtain [Emulsified slurry 2].

  [Emulsion slurry 2] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 5 hours, aging was carried out at 45 ° C. for 3 hours to obtain [Dispersion slurry 2].

[Toner 5]
[Toner 1] except that 0.6 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 140 nm was changed to 0.6 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 90 nm. [Toner 5] was produced in exactly the same manner.

[Toner 6]
In [Toner 1], 0.6 part of titanium oxide fine powder (treated with isobutyltrimethoxysilane) having an average particle diameter of 15 nm is 0.4 part, and silica fine powder having an average particle diameter of 140 nm (hexamethyldisilazane treatment) is 0. [Toner 6] was prepared in exactly the same manner except that 6 parts were changed to 0.6 parts of silica fine powder (hexamethyldisilazane treatment) having an average particle size of 490 nm.

[Toner 7]
[Toner 7] was produced in the same manner as in [Toner 3] except that 0.6 part of silica fine powder (hexamethyldisilazane treatment) having an average particle size of 140 nm was changed to 4.9 parts.

[Toner 8]
A toner was prepared in the same manner as in [Toner 1] except that the steps of ~ emulsification-solvent removal ~ were changed as follows.

  To 100 parts of the obtained toner base, 0.4 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 15 nm and 0.3 part of titanium oxide fine powder (isobutyltrimethoxysilane treatment) having an average particle diameter of 15 nm are used. And 0.6 part of silica fine powder having an average particle size of 140 nm (hexamethyldisilazane treatment) are added and mixed for 4 minutes at a rotation speed of 2010 rpm using Henschel 20C (Mitsui Mining Co., Ltd.). [Toner 8] was produced by removing the fluid.

~ Emulsification-Desolvation ~
[Pigment / WAX Dispersion 1] 749 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container, TK homomixer (manufactured by Tokushu Kika) at 7,000 rpm for 2 minutes After mixing, 1200 parts of [Aqueous Phase 1] was added to the container and mixed with a TK homomixer at a rotation speed of 16,000 rpm for 35 minutes to obtain [Emulsified Slurry 3].

  [Emulsion slurry 3] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C for 8 hours, aging was carried out at 45 ° C for 7 hours to obtain [Dispersion slurry 3].

[Toner 9]
A toner was prepared in the same manner as in [Toner 1] except that the steps of ~ emulsification-solvent removal ~ were changed as follows.

  To 100 parts of the obtained toner base, 0.5 parts of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 15 nm and 0.6 parts of titanium oxide fine powder (isobutyltrimethoxysilane treatment) having an average particle diameter of 15 nm are used. And 0.6 part of silica fine powder having an average particle size of 140 nm (hexamethyldisilazane treatment) are added and mixed for 4 minutes at a rotation speed of 2010 rpm using Henschel 20C (Mitsui Mining Co., Ltd.). [Toner 9] was produced by removing the fluid.

~ Emulsification-Desolvation ~
[Pigment / WAX Dispersion 1] 749 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container, TK homomixer (manufactured by Tokushu Kika) at 5,000 rpm for 2 minutes After mixing, 1200 parts of [Aqueous Phase 1] was added to the container and mixed with a TK homomixer at a rotational speed of 10,000 rpm for 25 minutes to obtain [Emulsified Slurry 4].

  [Emulsion slurry 4] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C for 8 hours, aging was carried out at 45 ° C for 7 hours to obtain [dispersed slurry 4].

[Toner 10]
A toner was prepared in the same manner as in [Toner 1] except that the steps of ~ emulsification-solvent removal ~ were changed as follows.

  To 100 parts of the obtained toner base, 0.5 parts of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 15 nm and 0.6 parts of titanium oxide fine powder (isobutyltrimethoxysilane treatment) having an average particle diameter of 15 nm are used. And 0.6 part of silica fine powder having an average particle size of 140 nm (hexamethyldisilazane treatment), followed by external addition treatment using Henschel 20C (Mitsui Mining Co., Ltd.) and mixing at a rotational speed of 2390 rpm for 7 minutes. [Toner 10] was produced by removing the fluid.

~ Emulsification-Desolvation ~
[Pigment / WAX Dispersion 1] 749 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container, and TK homomixer (manufactured by Tokushu Kika) for 2 minutes at 4,500 rpm After mixing, 1200 parts of [Aqueous Phase 1] was added to the container and mixed with a TK homomixer at 11,000 rpm for 25 minutes to obtain [Emulsified Slurry 5].

  [Emulsion slurry 5] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 8 hours, aging was carried out at 45 ° C. for 7 hours to obtain [Dispersion slurry 5].

[Toner 11]
A toner was prepared in the same manner as in [Toner 1] except that the steps of ~ emulsification-solvent removal ~ were changed as follows.

  To 100 parts of the obtained toner base, 0.4 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 15 nm and 0.3 part of titanium oxide fine powder (isobutyltrimethoxysilane treatment) having an average particle diameter of 15 nm are used. And 0.6 part of silica fine powder having an average particle size of 140 nm (hexamethyldisilazane treatment) are added and mixed for 4 minutes at a rotation speed of 2010 rpm using Henschel 20C (Mitsui Mining Co., Ltd.). [Toner 11] was produced by removing the fluid.

~ Emulsification-Desolvation ~
[Pigment / WAX Dispersion 1] 749 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container, TK homomixer (manufactured by Tokushu Kika) at 7,000 rpm for 2 minutes After mixing, 1200 parts of [Aqueous Phase 1] was added to the container, and mixed with a TK homomixer at 17,000 rpm for 40 minutes to obtain [Emulsified Slurry 6].

  [Emulsion slurry 6] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 8 hours, aging was carried out at 45 ° C. for 7 hours to obtain [Dispersed slurry 6].

[Toner 12]
In [Toner 1], except that 0.6 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 140 nm is changed to 0.6 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 70 nm. [Toner 12] was produced in exactly the same manner.

[Toner 13]
[Toner 13] was produced in the same manner as in [Toner 1] except that 0.6 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 140 nm was changed to 0.4 part.

[Toner 14]
[Toner 14] was produced in the same manner as in [Toner 1] except that 0.6 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 140 nm was changed to 5.3 parts.

  Table 1 shows the physical properties of Toners 1 to 14 produced as described above.

<Career>
Next, a specific example of manufacturing the carrier used for evaluation will be described. The carrier used in the present invention is not limited to these examples.
[Production of Carrier A]
Acrylic resin solution (solid content 50 wt%) 21.0 parts Guanamin solution (solid content 70 wt%) 6.4 parts Alumina particles [0.3 μm, specific resistance 10 ¹⁴ (Ω · cm)] 7.6 parts Silicon resin solution 65 0.0 part [solid content 23 wt% (SR2410: manufactured by Toray Dow Corning Silicone)]
Aminosilane 1.0 part [Solid content 100 wt% (SH6020: manufactured by Toray Dow Corning Silicone)]
60 parts of toluene 60 parts of butyl cellosolve was dispersed with a homomixer for 10 minutes to obtain a blend coating film forming solution of an acrylic resin and a silicone resin containing alumina particles. A fired ferrite powder [(MgO) _1.8 (MnO) _49.5 (Fe ₂ O ₃ ) _48.0 : average particle size; 35 μm] was used as the core material, and the coating film forming solution was applied to the surface of the core material. It was applied by a Spira coater (Okada Seiko Co., Ltd.) so as to have a thickness of 0.15 μm and dried. The obtained carrier was baked by standing in an electric furnace at 150 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 106 μm to obtain a carrier. The measurement of the binder resin film thickness was performed by observing the cross section of the carrier with a transmission electron microscope so that the coating film covering the carrier surface could be observed. Thus, carrier A having a weight average particle diameter of 35 μm was obtained.

[Production of Carrier B]
In carrier A, the average particle size of the sintered ferrite powder [(MgO) _1.8 (MnO) _49.5 (Fe ₂ O ₃ ) _48.0 : average particle size; 35 μm] of the core material was changed to 20 μm. In the same manner as Carrier A, Carrier B having a weight average particle size of 20 μm was obtained.

[Production of Carrier C]
In Carrier A, the average particle size of the sintered ferrite powder [(MgO) _1.8 (MnO) _49.5 (Fe ₂ O ₃ ) _48.0 : average particle size; 35 μm] of the core material was changed to 45 μm. In the same manner as Carrier A, Carrier C having a weight average particle size of 45 μm was obtained.

  Table 2 shows the physical properties of the carriers A to C thus prepared.

<Preparation of two-component developer>
Using toners 1-14 and ferrite carriers A-C, 7 parts by weight of toner with respect to 100 parts by weight of carrier are uniformly mixed and charged using a type of tumbler mixer in which the container rolls and stirs. An agent was prepared.

<Cleaning blade>
Table 3 shows the physical properties of the cleaning blade used for the evaluation. The blade used in the present invention is not limited to these examples.

<Contact conditions>
Table 4 shows the conditions for bringing the cleaning blade into contact with the electrophotographic photosensitive member.

<Evaluation machine conditions>
A machine in which the DocuColor 8000 Digital Press manufactured by Fuji Xerox Co., Ltd. was remodeled so that the linear velocity could be adjusted was used as the evaluation machine. Table 5 shows the linear velocity conditions of the evaluator.

<Evaluation method>
A running test for outputting a test image having an A4 size and an image area ratio of 5% was performed using an evaluation machine modified from DocuColor 8000 Digital Press manufactured by Fuji Xerox Co., Ltd.

  Specific modifications include the fact that the linear speed described in the evaluation machine conditions can be adjusted, and the charging portion has been changed from the corotron charger system to the contact roller charging system.

[Cleanability]
After the running of 100,000 sheets and 1,000,000 sheets, the photoconductors were taken out, the transfer residual toner on the photoconductor passed through the cleaning blade was collected with Nitto Denko's Printerac C (thickness 25 μm) and pasted on white paper, Using an 938 spectrodensitometer (X-Rite), measure 10 points of ID at an observation light source D ₅₀ and a viewing angle of 2 ° to calculate an average value, and the difference from the blank is 0.005 or less. ◎, 0.006 to 0.010 were evaluated as ◯, 0.011 to 0.015 as Δ, and 0.016 or more as ×.

[Filming / Medaka]
After the running of 100,000 sheets and 1,000,000 sheets, the photoreceptor was taken out, and the surface of the photoreceptor was visually observed and evaluated. Judgment criteria are as follows.
A: No filming or medaka was generated on the photoreceptor, and there was no problem at all.
○: Filming and medaka were slightly observed on the photoreceptor, but they were not visible on the image, and there was no practical problem.
Δ: Filming and medaka were generated on the photoconductor, but only a slight amount could be confirmed on the image and was not so noticeable.
X: Filming and medaka were generated on the photoreceptor, which could be confirmed on the image, and there was a problem in practical use.

[Charging roller dirt]
After the running of 100,000 sheets and 1,000,000 sheets, the charging roller was taken out, and the degree of contamination of the charging roller was visually determined. Good samples with no dirt were marked with ◎, those with slight dirt but no problem were marked with ○, those with slight dirt that could be used were marked with △, and those with bad dirt that could not be used.

  The evaluation combinations thus evaluated are shown in Table 6, and the obtained evaluation results are shown in Table 7. In addition, in the relationship diagram between the silica ratio and the linear velocity in FIG. 9, the positions corresponding to the respective examples and comparative examples are shown.

It is the schematic which shows an example of the image development apparatus of this invention. It is the schematic which shows an example of the contact-type charging device (roller type) of this invention. It is the schematic which shows an example of the contact-type charging device (brush type) of this invention. FIG. 2 is a schematic diagram illustrating an example of a process cartridge for an image forming apparatus according to the present invention. 1 is a schematic diagram illustrating an example of a fixing device of the present invention. FIG. 2 is a schematic diagram illustrating an example of a layer configuration of a belt used in the fixing device of the present invention. 1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus of the present invention. 1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus of the present invention. It is a figure which shows the relationship between the silica ratio of this invention, and a linear velocity.

Explanation of symbols

(About Figure 1)
700 Developing Unit 710 Developing Sleeve 720 Power Supply 730 Developing Unit 740 Photosensitive Member (Regarding FIG. 2)
DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 3 Power supply 21 Core metal 22 Conductive rubber layer

(About Figure 3)
DESCRIPTION OF SYMBOLS 1 Photoconductor 3 Power supply 4 Brush roller 41 Core metal 42 Brush part (About FIG. 4)
DESCRIPTION OF SYMBOLS 1 Process cartridge 11 Photoconductor 12 Charging means 13 Developing means 14 Cleaning means (About FIG. 5)
1 Heating roller 2 Fixing roller (opposite rotating body)
3 Heat resistant belt (toner heating medium)
4 Pressure roller (Pressure rotating body)
5 Temperature detection member 11 Recording medium T Toner image (FIG. 6)
3a Heat generation layer 3b Intermediate layer 3c Surface layer (FIG. 7)
100 Main body 130Bk Image forming part (Black)
130C Image forming unit (cyan)
130M Image forming unit (Magenta)
130Y Image forming unit (yellow)
140 Paper Feed Unit 150 Fixing Device 200Bk Developing Device (Black)
200C Developer (Cyan)
200M Developer (Magenta)
200Y Development device (yellow)
210Bk photoconductor (black)
210C photoconductor (cyan)
210M photoconductor (magenta)
210Y photoconductor (yellow)
220 Intermediate transfer belt 300Bk Cleaning device (black)
300C Cleaning device (Cyan)
300M Cleaning device (Magenta)
300Y Cleaning device (yellow)
(About Figure 8)
DESCRIPTION OF SYMBOLS 10 Intermediate transfer body 17 Intermediate transfer body cleaning apparatus 18 Image forming means 20 Tandem image forming apparatus 21 Exposure means 22 Secondary transfer means 25 Fixing apparatus 40, 40Y, 40C, 40M Photoconductor 62 Primary transfer apparatus 100 Copying apparatus main body

Claims (10)

At least a charging step for charging the surface of the electrophotographic photosensitive member, an exposure step for performing writing exposure on the surface of the charged electrophotographic photosensitive member, and developing the formed electrostatic latent image with toner to form a toner image on the surface of the electrophotographic photosensitive member. Development step to form, primary transfer step to transfer the formed toner image onto the intermediate transfer member, secondary transfer step to transfer the toner image on the intermediate transfer member onto the transfer material, and fixing the toner image on the transfer material A full-color image forming method having a fixing step and a cleaning step of cleaning the transfer residual toner on the surface of the electrophotographic photosensitive member,
The linear velocity (X) of the electrophotographic photosensitive member is in the range of 430 to 790 mm / sec ,
The toner, even without least include a resin and a colorant, weight average particle diameter of 2 to 6 [mu] m, an average circularity is 0.95 to 0.99, the surface of the toner, at least an average primary particle size 80 to 500 nm of silica is added ,
Present in the powder in the deposition to the performed cleaning process in the electrophotographic photosensitive member surface cleaning blade in contact with the counter direction at a contact pressure 0.15~0.4N / cm with respect to, of the cleaning blade edge The ratio (Sia / Sib) between the amount of silica (Sia) to be added and the amount of silica (Sib) present in the toner before replenishment is 0.0017X + 0.9789 ≦ (Sia / Sib) ≦ 0.0010X + 3.0141. It meets,
The full-color image forming method , wherein the cleaning blade has a hardness (specified by JIS-A hardness / JIS K6253 hardness test) of 70 to 80 ° . The full-color image forming method according to claim 1, wherein the toner is a toner prepared in an aqueous medium. The full color image forming method according to claim 1, wherein the carrier used in the developing step has a weight average particle diameter of 15 to 40 μm. The cleaning blade, a full-color image forming method according to any one of claims 1 to 3, wherein the rebound resilience at 25 ° C. is 20 to 60%. The image forming method, a full-color image forming method according to any one of claims 1 to 4, characterized in that is carried out by an electrophotographic image forming process tandem. The fixing step includes a heating roller made of magnetic metal and heated by electromagnetic induction, a fixing roller arranged in parallel with the heating roller, and stretched between the heating roller and the fixing roller, and the heating roller The toner heating medium is heated by the roller and is rotated by these rollers, and is pressed against the fixing roller via the toner heating medium, and is rotated and fixed in the forward direction with respect to the toner heating medium. full-color image forming method according to any one of claims 1 to 5, characterized in that is carried out by fixing means and a pressure roller to form a nip portion. The charging step, a full color image forming method according to any one of claims 1 to 6, characterized in that is carried out by charging means for applying a DC voltage obtained by superimposing at least alternating voltage. Charged in the charging step, by contacting a charging member in an electrophotographic photoreceptor, in any one of claims 1 to 7, characterized by being performed by the charging device which performs charging by applying a voltage to the charging member The full-color image forming method described. An electrophotographic photosensitive member for carrying at least a toner image, a charging unit for charging the surface of the electrophotographic photosensitive member, an exposure unit for performing writing exposure on the surface of the charged electrophotographic photosensitive member, and an electrostatic latent image formed Developing means for developing a toner image on the surface of the electrophotographic photosensitive member, primary transfer means for transferring the toner image formed on the surface of the electrophotographic photosensitive member onto the intermediate transfer member, and toner on the intermediate transfer member An image forming apparatus comprising: a secondary transfer unit that transfers an image onto a transfer material; a fixing unit that fixes a toner image on the transfer material; and a cleaning unit that cleans transfer residual toner on the surface of the electrophotographic photosensitive member. An image forming apparatus, wherein the image forming method according to claim 1 is carried out. 10. A process cartridge used in the full-color image forming apparatus according to claim 9 , wherein the electrophotographic photosensitive member for carrying a toner image, a developing unit, a charging unit for charging the electrophotographic photosensitive member, and the electrophotographic unit A process cartridge which integrally supports at least one means selected from cleaning means for cleaning a transfer residual toner on a surface of a photosensitive member and is detachable from a main body of an image forming apparatus.

Images