JP2010139819A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method by which even in printing with a small-diameter spherical toner, a high-quality print image free of streaky fog due to faulty cleaning of toner can be obtained without toner slipping. <P>SOLUTION: In the image forming method, toner remaining on a photoreceptor, on an intermediate transfer belt and on a secondary transfer member is cleaned with a cleaning blade. The toner comprises toner particles (A) and resin particles (B), the toner particles (A) have a circularity of 0.930-0.990 and a median diameter on a number basis (D<SB>50</SB>) of 3.0-8.0 μm, and the resin particles (B) have a circularity of 0.70-0.92 and the ratio of (D<SB>50</SB>) of the resin particles (B) to (D<SB>50</SB>) of the toner particles (A) is 0.15-0.60. The cleaning blade has an impact elastic modulus of 35-60% and a free length of 8-12 mm, and the cleaning blade is brought into contact in a counter direction at a contact angle of 15-30° and a contact pressure of 10-40 N/m. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming method.

  There is a growing demand for obtaining high-quality print images using an electrophotographic image forming method.

  As a method for obtaining a high-quality printed image, use of a toner having a small particle diameter has been studied.

  When the toner has a small particle size, the fluidity of the toner decreases, and image defects such as a part of the image pattern being lost may occur. In order to make it smooth, it has been made spherical.

  In general, in the electrophotographic image forming method, when transferring from an image carrier to a transfer material, it is necessary to remove the toner remaining on the image carrier without being transferred to the transfer material from the image carrier. As a method of cleaning the toner remaining on the image carrier, a method of bringing the edge of a cleaning blade made of an elastic material such as urethane rubber into contact with the surface of the image carrier is widely used. At this time, the cleaning blade is generally used with its end edge pressed against the running direction of the image carrier in the counter direction.

  It is known that a spherical toner having a small particle diameter is very difficult to clean if the cleaning blade as described above is used, because the toner slips through the cleaning blade.

  The phenomenon that the spherical toner slips through the cleaning blade is generally considered as follows. That is, the spherical toners collected at the edge (nip part) of the cleaning blade have a large contact area with each other and have the same particle size, and thus it is difficult to move over each other. As a result, a close-packed state (filled state with no gaps) is likely to occur, and the adhesion force is large due to the large contact area with the surface of the image carrier, and the force that pushes up the cleaning blade as if it were one aggregate. As a result, it is thought that the cleaning blade slips through. Even if the pressure contact force of the cleaning blade is simply increased, the cleaning effect is small, and in many cases, it cannot be applied due to problems such as reducing the life of the image carrier.

  Even when spherical toner is used, a method of cleaning the toner on the image carrier with a cleaning blade has been studied.

In particular,
(A) In a four-color full-color image forming apparatus, a developer contained in one color developer is used as an irregular toner produced by a pulverization method. A method is disclosed in which spherical toner and irregular toner are mixed in the vicinity of the nip portion so as not to form a close-packed state to prevent the cleaning blade from slipping through (see, for example, Patent Document 1).
(B) A method for preventing the cleaning blade from slipping through the use of a mixed powder material of a powder lubricant applied to the edge of the cleaning blade and an amorphous toner having an average particle size smaller than the spherical toner is disclosed. (For example, refer to Patent Document 2).
JP-A-8-254873 JP 2000-267536 A

The above (A) and (B) were examined. as a result,
(Problem of (A) above)
The above (A) can be applied to an image carrier that carries a plurality of color images, but cannot be applied to an image carrier of a tandem color image forming apparatus. In addition, since the irregular toner has not sufficiently reached the edge of the cleaning blade at the beginning of use of the image forming apparatus, when a large amount of spherical toner has reached, the spherical toner has passed through the cleaning blade by the mechanism described above. There was a problem.

(Problem of (B) above)
In (B), the damming portion is formed by the irregular toner, but the particles forming the damming portion and the particles to be dammed are the same toner, so that only the irregular toner is selectively applied to the edge tip of the cleaning blade. Is difficult to go. For this reason, a sufficient dampening portion cannot be formed, and there is a problem that spherical toner slips through.

  As described above, the present situation is that a method for satisfactorily cleaning the transfer residual toner with the cleaning blade has not yet been found.

  Further, in the image forming method for forming a patch image, the amount of toner to be cleaned is larger than that of the residual transfer toner, so that a load is imposed on cleaning the toner for forming the patch image (hereinafter also simply referred to as patch image toner).

  The patch image toner is used for correction so that the image density is maintained normally. Specifically, each color patch image of about 1.5 cm square is formed on a photoconductor, then transferred to an intermediate transfer belt, and the reflection density of each color patch image toner on the intermediate transfer belt is measured with a detection sensor, and normal It is used for controlling so as to obtain a high image density. The charging conditions and development conditions are controlled so that the patch image density is low, and the charging conditions and development conditions are controlled so that the patch image density is low, so that a good print image is always obtained. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide a toner that has good cleaning properties for transfer residual toner and patch image toner, has a high density and does not have fog, and can continuously obtain a high-quality print image.

  After the patch density measurement, the patch image toner on the intermediate transfer belt is cleaned by the intermediate transfer belt cleaning blade, or transferred from the intermediate transfer belt to the secondary transfer member and then cleaned by the secondary transfer member cleaning blade. The

  The present invention provides an image forming method capable of continuously obtaining a high-quality print image that does not cause toner slippage even when printed using a small-diameter and spherical toner and does not cause streaking due to poor toner cleaning. There is to do.

  The present invention can be achieved by adopting the following configuration.

1. An image in which the toner image formed on the photoconductor is transferred to a transfer material, and then the toner remaining on the photoconductor, the intermediate transfer belt, and the secondary transfer member is cleaned with a cleaning blade. In the forming method,
The toner comprises toner particles (A) and resin particles (B),
The toner particles (A) have a circularity of 0.930 to 0.990, and the median diameter (D ₅₀ ) on a number basis is 3.0 to 8.0 μm.
The circularity of the resin particles (B) is from 0.70 to 0.92, median diameter number-based median diameter _{(D 50)} toner particles (A) in the number-based _{(D 50) 0.15~0.} 60 times,
The rebound resilience of the cleaning blade is 35-60%, the free length is 8-12 mm,
The cleaning blade is contacted in the counter direction with respect to the rotation direction of the member to be cleaned, the contact angle for contact with the member to be cleaned is 15 to 30 degrees, and the contact pressure is 10 to 40 N / m. An image forming method.

  2. 2. The image forming method as described in 1 above, wherein the toner is prepared by mixing 0.05 to 5.0 parts by mass of resin particles (B) with respect to 100 parts by mass of toner particles (A).

  3. The photoconductor is formed by laminating a charge generation layer and a plurality of charge transport layers on a conductive support, and among the plurality of charge transport layers, the charge transport layer forming the outermost surface layer of the photoconductor contains inorganic particles. 3. The image forming method as described in 1 or 2 above, wherein:

  The image forming method of the present invention can continuously obtain a high-quality print image that does not cause toner slipping even when printed using a small-diameter spherical toner and does not cause streaking due to poor toner cleaning. It has an excellent effect.

  Even when printing is performed using a small-diameter and spherical toner, the present inventors do not cause toner slip on the photosensitive member, intermediate transfer belt, or secondary transfer member, and no streaking due to poor cleaning occurs. An image forming method capable of continuously obtaining quality print images was studied.

  As a result of various studies, in an image forming method in which residual transfer toner or patch image toner is cleaned from the surface of the photoreceptor, the surface of the intermediate transfer belt, or the surface of the secondary transfer member, the toner particles (A) are non-spherical and smaller than the toner particles. It has been found that when a toner containing an appropriate amount of resin particles (B) having a diameter is used, the resin particles (B) accumulate in the nip portion of the cleaning blade, and a clogging portion that prevents the toner particles (A) from slipping through is formed. It was.

  In addition, by optimizing the physical properties of the cleaning blade (for example, rebound resilience, free length) and its installation (for example, counter direction, contact angle, contact pressure), the desired delta shape at the nip of the cleaning blade I found that I can form.

  Specifically, a cleaning blade having a rebound resilience of 35 to 60% and a free length of 8 to 12 mm is used. The cleaning blade has a contact angle of 15 to 30 degrees and a contact pressure of 10 to 40 N / m. It was found that the desired Δ shape can be formed in the nip portion of the cleaning blade and the damming portion can be formed more effectively when the cleaning member abuts in the counter direction with respect to the traveling direction of the member to be cleaned.

  The Δ shape formed at the nip portion of the cleaning blade in the present invention is a triangular shape as shown by 6 in FIG.

  FIG. 1 is a schematic diagram showing main parameters of the cleaning blade.

  In FIG. 1, L is the free length of the cleaning blade, t is the thickness of the cleaning blade, α is the contact angle of the cleaning blade to the transfer member, θ is the set angle, d is the amount of biting, N is the contact pressure, A member to be cleaned, 10 is a blade holder, B is an end of the blade holder 10, and A is a tip A of the cleaning blade. The free length L of the cleaning blade represents the length of the tip point A of the cleaning blade (indicated by a dotted line in the drawing) that is assumed not to be deformed from the end B of the blade holder 10.

  FIG. 2 is a schematic view showing a state in which small particles (B) form a damming portion at the nip portion of the cleaning blade, and the toner particles (A) are dammed by the damming portion.

  In FIG. 2, 1 is a cleaning blade, 2 is toner particles (A), 3 is resin particles (B), 4 is a nip portion, 5 is a member to be cleaned, 6 is a Δ-shaped portion, and 7 is a member to be cleaned. A moving direction, 8 indicates a damming portion.

  The present invention will be described below.

  According to the image forming method of the present invention, the particle size and shape of the toner particle size (A) constituting the toner, the particle size and shape of the resin particle (B) are specified, the cleaning blade member, and the member whose cleaning blade is cleaned By optimizing the state of the tip portion in contact with the toner, the problem caused by the toner cleaning failure is solved.

  First, the configuration of the toner will be described.

<Composition of toner>
The toner used in the present invention is obtained by blending toner particles (A) having a specific particle size and shape and resin particles having a specific particle size and shape.

  A toner in which a specific amount of resin particles (B) is blended with 100 parts by mass of toner particles (A) is preferable.

<Characteristics of toner>
<Circularity of toner particles (A) and resin particles (B)>
The circularity of the toner particles (A) constituting the toner is 0.93 to 0.99. By setting the circularity within the above range, moderate fluidity is imparted to the toner itself, and the toner is less likely to be damaged or deteriorated even if the mechanical load in the image forming apparatus continues for a long time. That is, by imparting durability to the toner, a high-definition print image can be stably formed over a long period of time.

  The circularity of the resin particles (B) constituting the toner is 0.72 to 0.92. By setting the circularity within the above range, the damming portion can be stably formed without slipping through the nip portion of the cleaning blade.

  The circularity of the toner particles (A) and the resin particles (B) is a value calculated from the following equation.

When the toner particles (A) are calculated,
Circularity = (perimeter of a circle having the same projected area as the toner particle (A) image) / (perimeter of the toner projected image)
The circularity of the toner particles (A) can be calculated using a flow particle image analyzer “FPIA-2100 (manufactured by Sysmex)”.

  Specifically, the toner is blended with an aqueous solution containing a surfactant to separate the toner particles (A) and the resin particles (B). After the separated toner particles (A) are dispersed by ultrasonic dispersion for 1 minute, using “FPIA-2100”, measurement is performed at an appropriate density with an HPF detection number of 3000 to 10000 in HPF (high magnification imaging) mode. I do. Within this range, reproducible measurement values can be obtained.

  The resin particles (B) can be calculated in the same manner as the toner particles (A).

<Median diameter (D ₅₀ ) based on the number of toner particles (A) and resin particles (B)>
The median diameter (D ₅₀ ) on the basis of the number of toner particles (A) is 3.0 to 8.0 μm. By setting the median diameter (D ₅₀ ) on the basis of the number within the above range, appropriate fluidity is imparted to the toner itself, and a high-definition printed image can be stably formed over a long period of time.

The median diameter (D ₅₀ ) based on the number of resin particles (B) is 0.15 to 0.60 times that of the toner particles (A). By setting the magnification of the median diameter (D ₅₀ ) on the basis of the number within the above range, the damming portion can be satisfactorily formed.

Specifically, when the median diameter number-based toner particles _{(A) (D 50)} is used as a 3.0μm is median diameter number-based resin particles _{(B) (D 50)} of 0.45 Use a material having a thickness of ˜1.8 μm. When the median diameter (D ₅₀ ) based on the number of toner particles (A) is 8.0 μm, the median diameter (D ₅₀ ) based on the number of resin particles (B) is 1.2 to 4.8 μm. Use things.

The median diameter (D ₅₀ ) on the basis of the number of toner particles (A) and resin particles (B) is measured using an apparatus in which a computer system for data processing is connected to “Multisizer 3” (manufactured by Beckman Coulter). It is possible to calculate.

The median diameter (D ₅₀ ) on the basis of the number using “Multisizer 3” is measured according to the following procedure.
(1) The toner is blended with an aqueous solution containing a surfactant, the toner particles (A) and the resin particles (B) are separated, and measurement samples of the toner particles (A) and the resin particles (B) are prepared.
(2) After 0.02 g of the measurement sample is sufficiently blended with 20 ml of the surfactant solution, ultrasonic dispersion treatment is performed for 1 minute to prepare a dispersion of the measurement sample.
(3) The dispersion of the measurement sample is pipetted into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand until the measurement concentration is 5 to 10%.
(4) Set the measuring machine count to 2500 and start measurement. The aperture diameter of “Multisizer 3” is 100 μm.

  Next, preparation of toner particles (A), resin particles (B), and toner will be described.

<Preparation of toner particles (A)>
The toner particles (A) according to the present invention are composed of particles containing at least a resin, a wax, and a colorant. The method for producing the toner particles (A) according to the present invention is not particularly limited, and can be produced by a conventional toner production method. That is, a so-called pulverized toner production method (pulverization method) for producing toner particles (A) through kneading, pulverization, and classification steps, or polymerization of a polymerizable monomer, while simultaneously controlling the shape and size of the particles It can be produced by applying a so-called polymerized toner manufacturing method (for example, an emulsion polymerization method, a suspension polymerization method, a polyester elongation method, etc.).

  Among these, production by a polymerization method is a preferred production method because desired toner particles (A) can be formed while controlling the shape and size of the particles in the production process.

  Among them, the emulsion association method in which resin particles of around 120 nm are formed in advance by an emulsion polymerization method or a suspension polymerization method and particles are formed through a process of aggregating the resin particles can be said to be one of effective production methods.

Below, the example of preparation of the toner particle (A) by an emulsion association method is demonstrated. In the emulsification association method, toner particles (A) are prepared generally through the following procedure. That is,
(1) Preparation process of resin particle dispersion (2) Preparation process of colorant particle dispersion (3) Aggregation / fusion process of resin particles (4) Aging process (5) Cooling process (6) Cleaning process (7) Drying step As required (8) It can be produced through an external additive treatment step.

Hereinafter, each step will be described.
(1) Preparation Step of Resin Particle Dispersion This step is a step of forming resin particles having a size of about 120 nm by introducing a polymerizable monomer that forms resin particles into an aqueous medium and performing polymerization. is there. It is also possible to form a resin particle containing a wax. In this case, the wax is contained by dissolving or dispersing the wax in a polymerizable monomer and polymerizing it in an aqueous medium. The resulting resin particles are formed.
(2) Step of producing colorant particle dispersion This is a step of producing a colorant particle dispersion having a size of about 110 nm by dispersing a colorant in an aqueous medium.
(3) Aggregation / fusion process of resin particles This process is a process in which resin particles and colorant particles are aggregated in an aqueous medium, and these aggregated particles are fused to obtain particles. In this step, an alkali metal salt, an alkaline earth metal salt, or the like is added as an aggregating agent to an aqueous medium in which resin particles and colorant particles are present, and then the glass transition point of the resin particles is higher than the glass transition point. In addition, the resin particles are fused together at the same time as the aggregation proceeds by heating to a temperature equal to or higher than the melting peak temperature (° C.) of the mixture. Specifically, the resin particles and the colorant particles produced by the above-described procedure are added to the reaction system, and a coagulant such as magnesium chloride is added to simultaneously aggregate the resin particles and the colorant particles. Particles are formed by fusing together. Then, when the particle size reaches the target size, a salt such as saline is added to stop aggregation.
(4) Ripening step This step is a step of aging until the particle shape has a desired circularity by heat-treating the reaction system subsequent to the aggregation / fusion step.
(5) Cooling step This step is a step of cooling the particle dispersion. As a cooling treatment condition, cooling is performed at a cooling rate of 1 to 20 ° C./min. The cooling treatment method is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.
(6) Washing step This step includes a step of solid-liquid separation of the particles from the particle dispersion cooled to a predetermined temperature in the above step, and a surfactant or the like from the particles solid-liquid separated into wet cake-like aggregates. It consists of a cleaning process for removing deposits such as aggregating agents.

In the washing treatment, the filtrate is washed with water until the electric conductivity of the filtrate reaches 10 μS / cm. Examples of the filtration method include a centrifugal separation method, a vacuum filtration method using Nutsche and the like, and a filtration method using a filter press and the like, and are not particularly limited.
(7) Drying step This step is a step of drying the washed particles to obtain dried particles. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like.

The moisture of the dried particles is preferably 5% by mass or less, more preferably 2% by mass or less. In addition, when the dried particles are aggregated with weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.
(8) External additive treatment step This step is a step of preparing toner particles (A) by mixing an external additive with the dried particles. As an external additive mixing apparatus, a mechanical mixing apparatus such as a Henschel mixer or a coffee mill can be used.

  Further, the toner particles (A) according to the present invention may be produced by controlling the circularity by heat-treating particles produced by a pulverization method. Specifically, it can be produced by the following procedure.

  In the toner production by the pulverization method, first, toner components such as a binder resin, a charge control agent, and a colorant are mixed using a Henschel mixer or the like, and the mixture is then mixed in a kneader such as a twin screw extruder kneader. Input and knead (kneading step).

  The kneaded product is cooled and then loosely pulverized with a feather mill, a hammer mill or the like, and further finely pulverized with a mechanical pulverizer such as a kryptron or an airflow pulverizer such as a jet mill (pulverization step).

  Next, the finely pulverized product is put into a mechanical or airflow classifier and subjected to a classification process to obtain particles having a desired particle size.

  Thereafter, the particles are heat-treated using a circularity control device to control the circularity of the particles. As an apparatus for controlling the circularity, there can be mentioned a “Saffusion system (manufactured by NPK)” which controls the circularity by bringing hot air into contact with particles.

  Thereafter, an external additive is added to the particles produced through the above procedure to produce toner particles (A). Examples of the apparatus for performing the external additive treatment include a mechanical mixing apparatus such as a Henschel mixer and a coffee mill.

  A circularity control device that controls the circularity of the toner particles (A) will be described.

  FIG. 3 is a schematic diagram illustrating an example of a circularity control device that controls the circularity of the toner particles (A).

  As shown in FIG. 3, the circularity control device is provided with a cylindrical hot air supply member 420 at the top of a treatment tank 410 for heat-treating particles, and a dispersion chamber 430 is provided around the hot air supply member 420. A raw material supply member 431 that blows a dispersed air flow obtained by dispersing particles into the dispersion chamber 430 is connected to the outer peripheral side of the dispersion chamber 430, while the inner peripheral side of the dispersion chamber 430 has a predetermined circumferential direction. A plurality of raw material injection nozzles 432 are provided at intervals.

  Hot air is jetted from the hot air supply member 420 into the treatment tank 410, while a dispersed air stream in which particles are dispersed from the raw material supply member 431 is blown into the dispersion chamber 430. The dispersed air current blown into the dispersion chamber 430 is jetted into the treatment tank 410 from the raw material jet nozzles 432 toward the hot air jetted from the hot air supply member 420.

  When the dispersed air current ejected from each of the raw material ejection nozzles 432 is ejected toward the hot air, the angle formed by the dispersed air current and the hot air may become large. In this case, since the dispersed air current is jetted so as to cross the hot air, the dispersed air current easily collides with the hot air, and the particles in the dispersed air current easily aggregate.

  On the other hand, the angle formed by the dispersed air current ejected from each raw material ejection nozzle 432 and the hot air ejected from the hot air supply member 420 may be small. In this case, since the dispersed air stream is not easily taken into the hot air, the particles in the dispersed air stream are not sufficiently heat-treated. From the above view, the angle between the dispersed air current ejected from each raw material ejection nozzle 432 and the hot air ejected from the hot air supply member 20 is preferably in the range of 20 to 40 °, preferably 25 to 35 °. .

  The heat treatment apparatus shown in FIG. 3 is provided with rectifying means for rectifying hot air sprayed from the hot air supply member 420 into the processing tank 410. Specifically, the partition member provided in the hot air supply member 420 is provided with this partition, whereby the hot air passage in the hot air supply member 420 is composed of a plurality of small passages. Thus, the hot air passing through the hot air supply member 420 is corrected by the partition member provided in the hot air supply member 420 by passing through a plurality of small passages partitioned by the partition member, The rectified state is supplied into the processing tank 410.

  When the rectified hot air is injected into the treatment tank 410 from the hot air supply member 420, there is no turbulence due to the hot air, so that some of the particles in the dispersed air flow are kept away from the hot air, or are gathered locally in the hot air. The particles are uniformly heat-treated. In addition, when cooling the particles heat-treated with the cold air introduced into the treatment tank 410 from the air introduction port 411 provided on the upper surface of the treatment tank 410, appropriate cooling is performed and unnecessary bonding between the particles is suppressed. Is done.

  Next, members (resin, wax, colorant, etc.) used for producing the toner particles (A) will be described.

<resin>
Examples of the resin used for producing the toner particles (A) include polymers produced by polymerizing polymerizable monomers represented by vinyl monomers as shown in the following (1) to (10). It is representative. Specific examples include those obtained by polymerizing the following vinyl monomers alone or in combination.
(1) Styrene or styrene derivatives Styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-chloro styrene, 3,4-dichloro styrene, p-phenyl styrene, p-ethyl styrene 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, etc. (2) Methacrylic acid ester derivatives Methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate , Lauryl methacrylate , Phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, etc. (3) Acrylic acid ester derivatives Methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate , N-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc. (4) olefins ethylene, propylene, isobutylene, etc. (5) vinyl esters vinyl propionate, vinyl acetate, benzoe (6) Vinyl ethers Vinyl vinyl ether, vinyl ethyl ether, etc. (7) Vinyl ketones Vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, etc. (8) N-vinyl compounds N Vinylcarbazole, N- vinyl indole, N- vinylpyrrolidone (9) vinyl compounds vinyl naphthalene, vinyl pyridine and the like (10) acrylic acid or methacrylic acid derivative acrylonitrile, methacrylonitrile, acrylamide.

  Moreover, it is also possible to use combining the polymerizable monomer which has an ionic dissociation group as a polymerizable monomer which comprises resin. Examples of the ionic dissociation group include substituents such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group, and the polymerizable monomer having an ionic dissociation group has these substituents.

  Specific examples of the polymerizable monomer having an ionic dissociation group are given below.

  Acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfone Acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxypropyl methacrylate and the like.

  Furthermore, it is also possible to use a polyfunctional vinyl as a polymerizable monomer constituting the resin to obtain a resin having a crosslinked structure. Specific examples of the polyfunctional vinyls are listed below.

  Divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, and the like.

<wax>
Examples of the wax constituting the toner particles (A) include conventionally known waxes, and specific examples thereof include the following.
(1) Long-chain hydrocarbon wax Polyolefin wax such as polyethylene wax and polypropylene wax, paraffin wax, sazole wax, etc. (2) Ester wax Trimethylolpropane tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrasteare Rate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitic acid, distearyl maleate, etc. (3) Amide wax Ethylenediamine dibehenyl amide, trimellitic acid tristearyl amide, etc. (4) Dialkyl ketone waxes, distearyl ketone, etc. (5) Others Carnaubawack , Montan waxes, and the like.

  The melting point of the wax is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. By keeping the melting point of the wax within the above range, the heat-resistant storage stability of the toner is ensured, and at the same time, stable toner image formation can be performed without causing cold offset or the like even when fixing at a low temperature. Further, the wax content in the toner is preferably 1% by mass to 30% by mass, and more preferably 5% by mass to 20% by mass.

<Colorant>
As the colorant constituting the toner particles (A), a known inorganic or organic colorant can be used. Specifically, the following colorants can be mentioned.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment Red 57; 1, Pigment Red 48; 3, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, and the like.

  Examples of the colorant for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  Said colorant can be used individually or in combination of 2 or more types.

  The addition amount of the colorant is preferably 1 to 30% by mass and more preferably 2 to 20% by mass with respect to the toner particles (A).

  Further, as the colorant, a surface-modified one can also be used. As the surface modifier, conventionally known ones can be used, and specifically, silane coupling agents, titanium coupling agents, aluminum coupling agents and the like can be preferably used.

<Charge control agent>
The toner particles (A) according to the present invention may contain a charge control agent as necessary. Various known compounds can be used as the charge control agent.

<External additive>
The toner particles (A) according to the present invention can be used by mixing external additives as necessary.

The particle diameter of the external additive is preferably not more than 0.14 times the median diameter (D ₅₀ ) based on the number of toner particles (A).

  By adding the external additive, the fluidity and chargeability of the toner are improved, and the cleaning property is improved. The type of external additive is not particularly limited, and examples thereof include the following inorganic fine particles, organic fine particles, and lubricants.

  As the inorganic fine particles, conventionally known fine particles can be used. For example, silica, titania, alumina, strontium titanate fine particles and the like are preferable. Moreover, what hydrophobized these inorganic fine particles as needed can also be used.

  Specific examples of silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., HVK-2150, H- 200, commercial products TS-720, TS-530, TS-610, H-5, MS-5 and the like manufactured by Cabot Corporation.

  Specifically, as titania fine particles, commercially available products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., commercially available products MT-100S, MT-100B, MT-500BS, MT-600, MT-600SS manufactured by Teika, JA-1, commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB manufactured by Idemitsu Kosan Co., Ltd. IT-OC etc. are mentioned.

  Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  As the organic fine particles, organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Specifically, a homopolymer such as styrene or methyl methacrylate or a copolymer thereof can be used.

  Specific examples of lubricants include zinc stearate, aluminum, copper, magnesium, calcium and other salts, zinc oleate, manganese, iron, copper, magnesium, etc., zinc palmitate, copper, magnesium And salts such as calcium, zinc linoleic acid, salts such as calcium, zinc ricinoleic acid, and salts such as calcium.

  The addition amount of these external additives and lubricants is preferably 0.1 to 10.0% by mass with respect to the toner particles (A). Examples of methods for adding external additives and lubricants include methods using various known mixing devices such as a turbuler mixer, a Henschel mixer, a nauter mixer, and a V-type mixer.

<Preparation of resin particles (B)>
The resin particles (B) according to the present invention are preferably prepared by pulverizing resin powder with a mechanical pulverizer and then classifying it.

The degree of circularity of the resin particles (B) and the median diameter (D ₅₀ ) based on the number can be controlled by pulverization conditions and classification conditions.

  Examples of the resin include polytetrafluoroethylene (PTFE) resin, polyethylene (PE) resin, polypropylene (PP) resin, acrylic / styrene resin, and the like.

  The resin particles (B) may be prepared by adding an external additive, like the toner particles (A).

<Production of toner>
The toner used in the present invention can be prepared by blending toner particles (A) and resin particles (B) at a specific ratio.

  The mixing ratio of the resin particles (B) to the toner particles (A) is preferably 0.05 to 5.0 parts by mass of the resin particles (B) with respect to 100 parts by mass of the toner particles (A).

  As a mixing device for mixing the toner particles (A) and the resin particles (B), a mechanical mixing device such as a known Henschel mixer or a coffee mill can be used.

<< Preparation of developer >>
The toner according to the present invention can be used as a two-component developer composed of a carrier and a toner, or as a non-magnetic one-component developer composed only of a toner. It is preferable for obtaining a print image of high image quality.

  The two-component developer according to the present invention can be prepared by mixing 3 to 10 parts by mass of toner with 100 parts by mass of a carrier using a mechanical mixer.

  The mixing method is not particularly limited, and mixing can be performed using a known mixer.

  As a carrier constituting the two-component developer, an uncoated carrier composed only of magnetic material particles such as iron and ferrite, a resin-coated carrier whose magnetic material particle surface is coated with a resin, or a mixture of resin and magnetic powder. Any of the resin-dispersed carriers obtained as described above may be used. The average particle size of the carrier is preferably about 30 to 150 μm in terms of volume average particle size.

《Cleaning blade》
The cleaning blade according to the present invention is used for cleaning the toner remaining on the member to be cleaned. Here, the remaining toner refers to transfer residual toner on the photosensitive member, transfer residual toner on the intermediate transfer belt, and patch image toner on the secondary transfer member.

  The cleaning blade used in the present invention has a specific rebound resilience and a specific free length.

  The rebound resilience of the cleaning blade is 35-60% at room temperature (20 ° C.).

  When the rebound resilience is 35% or more, the cleaning blade has sufficient vibration energy and a cleaning effect can be exhibited, and image fogging due to poor cleaning, potty failure and muscle failure do not occur.

  If the rebound resilience is 60% or less, the vibration energy of the cleaning blade will not be excessive, and the cleaning blade can be prevented from splashing on the photoconductor, intermediate transfer belt and secondary transfer member, and horizontal line fog (black) Streak) does not occur.

  The rebound resilience is measured by the measurement method specified in JIS k7311.

  The free length of the cleaning blade is 6-15 mm. When the free length is 6 mm or more, the cleaning blade has sufficient vibration energy and a cleaning effect can be exhibited, and image fogging due to poor cleaning, potty failure and muscle failure do not occur. If the free length is 15 mm or less, the vibration energy of the cleaning blade does not become excessive, and the cleaning blade can be prevented from splashing on the photosensitive member, the intermediate transfer belt and the secondary transfer member. Does not occur.

  The thickness of the cleaning blade is preferably 0.5 to 10 mm.

  As a material of the cleaning blade, urethane rubber, silicone rubber, fluorine rubber, chloroprene rubber, butadiene rubber, or the like can be used. Among these, urethane rubber is preferable in terms of excellent wear characteristics.

  The shape and material of the cleaning blade are appropriately selected according to various conditions such as thickness, toner characteristics, characteristics of the photosensitive member, intermediate transfer belt and secondary transfer member, cleaning blade contact angle and contact pressure. The

<Image forming method>
The image forming method of the present invention is a method having at least a cleaning step using a cleaning blade. Specifically, it is an image forming method used for an image forming apparatus for creating a monochrome print or a color print.

  In the color image formation method, a patch image is formed on the intermediate transfer belt for each fixed print, the reflection density of this patch image is measured, charging and development conditions are controlled so that the reflection density becomes a prescribed value, and continued. High quality print images are obtained.

  Specifically, the patch image formed on the photoconductor is directly transferred to the intermediate transfer belt, and the reflection density of the patch image is measured by a detection sensor installed on the circumference of the intermediate transfer belt, and the measured reflection density is measured. Thus, the charging conditions and the development conditions are controlled, and a stable high-quality print image can be continuously obtained.

  After the reflection density of the patch image is measured, the patch image toner on the intermediate transfer belt is cleaned by the intermediate transfer belt cleaning means described below or transferred from the intermediate transfer belt to the secondary transfer member. Thereafter, the secondary transfer member is cleaned by a cleaning means.

  FIG. 4 is a schematic cross-sectional view illustrating an example of a color image forming apparatus having a cleaning unit using a cleaning blade.

  First, an outline of a color image forming apparatus having a photoreceptor cleaning means, an intermediate transfer belt cleaning means, and a secondary transfer member cleaning means will be described.

  The image forming apparatus GS is called a tandem type color image forming apparatus, and arranges image forming units that form yellow, magenta, cyan, and black color toner images along the moving direction of the intermediate transfer belt. The color toner image formed on the image carrier of the image forming unit is transferred onto the intermediate transfer belt and superimposed, and then transferred onto the transfer material at once.

  In the figure, a document image placed on an image reading device SC arranged at a position occupying the upper portion of the image forming device GS is scanned and exposed by an optical system, read by a line image sensor CCD, and read by the line image sensor CCD. The analog signal subjected to photoelectric conversion is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in an image processing unit, and then an image data signal is sent to the exposure optical system 3 serving as an image writing unit.

  As the intermediate transfer belt, an endless belt-like intermediate transfer belt 6 is indicated.

  In the figure, four sets of process units 100 are provided on the peripheral edge of the intermediate transfer belt 6 for image formation for each color of yellow (Y), magenta (M), cyan (C), and black (K). It has been. The process unit 100 is arranged in a vertical column along the intermediate transfer belt 6 with respect to the rotation direction of the vertical intermediate transfer belt 6 indicated by the arrows in the drawing as a color toner image forming unit. , K in this order.

  Each of the four sets of process units 100 has a common structure, and each includes a photosensitive drum 1, a charger 2 as a charging unit, an exposure optical system 3 as an image writing unit, a developing device 4, and an image. It comprises a photoconductor cleaning device 190 as a carrier cleaning means.

  The photosensitive drum 1 is rotated in the direction of the arrow in a grounded state by power from a driving source (not shown), for example, at a linear velocity of about 80 to 280 mm / s, preferably 220 mm / s.

  Around the photosensitive drum 1, an image forming unit including a charger 2 as a charging unit, an exposure optical system 3 as an image writing unit, and a developing device 4 is set as a photosensitive drum indicated by an arrow in the figure. 1 with respect to the rotation direction.

  The charger 2 as a charging unit is attached in close proximity to the photosensitive drum 1 in a direction parallel to the rotation axis of the photosensitive drum 1. The charger 2 includes a discharge wire as a corona discharge electrode that applies a predetermined potential to the photosensitive layer of the photosensitive drum 1, and performs a charging action (negative charging in the present embodiment) by corona discharge having the same polarity as the toner. A uniform potential is applied to the photosensitive drum 1.

  An exposure optical system 3 serving as an image writing means rotationally scans laser light emitted from a semiconductor laser (LD) light source (not shown) in a main scanning direction by a rotating polygon mirror (no symbol), and an fθ lens (no symbol). ), A reflection mirror (without a symbol), etc., the photosensitive drum 1 is exposed to an electrical signal corresponding to an image signal (image writing), and an electrostatic latent image corresponding to a document image is formed on the photosensitive layer of the photosensitive drum 1. Form an image.

  The developing device 4 as a developing unit is configured to supply a two-component developer of each color of yellow (Y), magenta (M), cyan (C), and black (K) charged to the same polarity as the charging polarity of the photosensitive drum 1. A developing roller 4a, which is a developer carrier made of, for example, a cylindrical nonmagnetic stainless steel or aluminum material having a thickness of 0.5 to 1 mm and an outer diameter of 15 to 25 mm, is housed. The developing roller 4a is kept in contact with the photosensitive drum 1 with a predetermined gap (for example, 100 to 1000 μm) by an abutting roller (not shown), and rotates in the same direction as the rotational direction of the photosensitive drum 1. At the time of development, a photoconductor drum is applied by applying to the developing roller 4a a DC voltage having the same polarity as the toner (negative polarity in the present embodiment) or a developing bias voltage that superimposes an AC voltage on the DC voltage. The reversal development is performed on the upper exposed portion.

The intermediate transfer belt 6 has a volume resistivity of about 1.0 × 10 ^{7 to} 1.0 × 10 ⁹ Ω · cm and a surface resistivity of about 1.0 × 10 ^{10 to} 1.0 × 10 ¹² Ω / □. A semiconductive endless (seamless) resin belt member is used. As a resin belt member. Specifically, a semiconductive resin having a thickness of 0.05 to 0.5 mm in which a conductive material is dispersed in engineering plastics such as modified polyimide, thermosetting polyimide, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride, and nylon alloy. A film can be used. In addition to this, a semiconductive rubber belt having a thickness of 0.5 to 2.0 mm in which a conductive material is dispersed in silicone rubber, urethane rubber or the like can also be used as the resin belt member. The intermediate transfer belt 6 is wound around a plurality of roller members including a tension roller 6a and a backup roller 6B facing the secondary transfer roller, and is supported so as to be rotatable in the vertical direction.

  The primary transfer roller 7 as a first transfer unit for each color is made of a roller-like conductive member using foamed rubber such as silicone or urethane, for example, and the photosensitive drum 1 for each color with the intermediate transfer belt 6 interposed therebetween. The transfer area is formed between the endless belt-like intermediate transfer 6 and the photosensitive drum 1 by pressing the back surface of the endless belt-like intermediate transfer 6. A DC constant current having a polarity opposite to that of the toner (positive polarity in the present embodiment) is applied to the primary transfer roller 7 by constant current control, and a toner image on the photosensitive drum 1 is formed by a transfer electric field formed in the transfer area. The image is transferred onto the intermediate transfer belt 6.

  The toner transferred onto the intermediate transfer belt 6 is transferred onto the transfer material P. A detection sensor 8 that measures the reflection density of the patch image toner is provided on the circumference of the intermediate transfer belt 6.

  In order to clean the residual toner on the intermediate transfer belt 6, an intermediate transfer belt cleaning device 190A is provided.

  Further, a secondary transfer member cleaning device 70 is provided for cleaning the patch image toner on the secondary transfer member 7A.

  Next, an image forming process (image forming process) will be described.

  When the image recording is started, the photosensitive drum drive motor (not shown) is rotated to rotate the Y photosensitive drum 1 in the direction indicated by the arrow in the figure, and a potential is applied to the Y photosensitive drum 1 by the Y charger 2. . After the Y photosensitive drum 1 is applied with a potential, the Y exposure optical system 3 performs exposure (image writing) with an electrical signal corresponding to the first color signal, that is, the Y image data. An electrostatic latent image corresponding to a yellow (Y) image is formed on the body drum 1. The latent image is reversely developed by the Y developing device 4 to form a toner image made of yellow (Y) toner on the Y photosensitive drum 1. The Y toner image formed on the Y photosensitive drum 1 is transferred onto the intermediate transfer belt 6 by a primary transfer roller 7 as a primary transfer means.

  Next, a potential is applied to the M photosensitive drum 1 by the M charger 2. After the M photoconductor drum 1 is applied with a potential, the M exposure optical system 3 performs exposure (image writing) with an electric signal corresponding to the first color signal, that is, the M image data. An electrostatic latent image corresponding to a magenta (M) image is formed on the body drum 1. The latent image is reversely developed by the M developing device 4 to form a toner image made of magenta (M) toner on the M photoconductor drum 1. The M toner image formed on the M photosensitive drum 1 is transferred onto the endless belt-like upper intermediate transfer belt 6 by being superimposed on the Y toner image by a primary transfer roller 7 as a primary transfer means.

  By a similar process, a toner image made of cyan (C) toner formed on the C photoconductive drum 1 and a toner image made of black (K) toner formed on the K photoconductive drum 1 are obtained. The toner images are sequentially superimposed on the intermediate transfer belt 6, and a superimposed color toner image composed of Y, M, C, and K toners is formed on the peripheral surface of the intermediate transfer belt 6.

  The toner remaining on the peripheral surface of each photoreceptor drum 1 after the transfer is cleaned by the photoreceptor cleaning device 190.

  On the other hand, the transfer material P as recording paper accommodated in the paper feed cassettes 20A, 20B, and 20C is fed by the feed roller 21 and the paper feed roller 22A provided in the paper feed cassettes 20A, 20B, and 20C, respectively, and conveyed. A secondary transfer roller serving as a secondary transfer unit that is transported on the path 22 by transport rollers 22B, 22C, and 22D, to which a voltage having a polarity opposite to that of the toner (a positive polarity in this embodiment) is applied via the registration roller 23. The superimposed color toner images (color images) formed on the intermediate transfer belt 6 are transferred onto the transfer material P in a lump in the transfer area of the secondary transfer roller 7A.

  The transfer material P onto which the color image has been transferred is heated and pressed at the fixing nip NA formed by the heating member 17a and the pressure roller 17b of the fixing device 17, and is fixed by the paper discharge roller 24. It is placed on the outer paper discharge tray 25.

  The above describes the state in which image formation is performed on the first surface, which is one side of the transfer material P. In the case of duplex copying, the sheet discharge switching member 26 is switched, the sheet guide portion 26A is opened, and the transfer is performed. The material P is conveyed in the direction of a broken line arrow.

  Further, the transfer material P is transported to the lower transport path 27B by the transport mechanism 27A, switched back by the sheet reversing portion 27C, and the transport path is switched by the branching portion 27D. And is conveyed into the duplex copying paper feed unit 130.

  The transfer material P moves in the paper feeding direction through a conveyance guide 131 provided in the duplex copying paper supply unit 130, and the transfer material P is re-fed by the paper supply roller 132 and guided to the conveyance path 22.

  Then, as described above, the transfer material P is conveyed in the direction of the secondary transfer roller 7A, the toner image is transferred to the second surface which is the back surface of the transfer material P, fixed by the fixing device 17, and then the paper discharge tray. 25 is discharged.

  Further, after the color image is transferred onto the transfer material P by the secondary transfer roller 7A as the secondary transfer means, the residual toner on the intermediate transfer belt 6 that has separated the curvature of the transfer material P becomes the intermediate transfer belt cleaning device 190A. It is cleaned by.

  Further, the patch image toner on the secondary transfer roller 7 </ b> A is removed by the cleaning blade 71 of the secondary transfer member cleaning device 70.

  Next, members (photoconductor, intermediate transfer belt, secondary transfer member) cleaned by the cleaning blade will be described.

<< Members to be cleaned (photoconductor, intermediate transfer belt, secondary transfer member) >>
<Photoconductor>
The photoreceptor used in the present invention is formed by laminating a charge generation layer and a plurality of charge transport layers on a conductive support, and the charge transport layer forming the outermost surface layer of the photoreceptor among the plurality of charge transport layers. (Hereinafter also referred to as a protective layer) contains inorganic particles.

  Hereinafter, the conductive support, the conductive layer, the intermediate layer, and the charge generation layer, the charge transport layer, and the protective layer, which are the photosensitive layer, constituting the photoreceptor used in the present invention will be described.

(Conductive support)
As the conductive support used in the photosensitive member, either a sheet shape or a cylindrical shape may be used, but a cylindrical shape is preferable in order to design the image forming apparatus compactly.

  Cylindrical conductive support means a cylindrical conductive support necessary to be able to form an endless image by rotating. Conductivity within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. Conductive support is preferred. By setting the straightness and shake range within the above ranges, good image formation can be achieved.

As a material for the conductive support, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.

(Conductive layer)
In the photoreceptor according to the present invention, a conductive layer may be provided on a conductive support. The conductive layer is a layer basically composed of a binder resin and a conductive pigment. The thickness of the conductive layer is preferably from 0.3 to 20 μm, more preferably from 1 to 15 μm.

  The binder resin used in the conductive layer is a thermosetting resin so as not to dissolve in the solvent used in the intermediate layer in order to maintain a uniform coating film even after the intermediate layer is applied.

(Middle layer)
In the present invention, an intermediate layer (undercoat layer) is provided between the conductive support and the photosensitive layer in order to improve adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the conductive support. Including). Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Of these resins, a polyamide resin is preferable as a resin capable of reducing an increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 1.0 μm.

  Examples of the intermediate layer preferably used in the present invention include an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent or a titanium coupling agent. The thickness of the intermediate layer using a curable metal resin is preferably 0.1 to 2 μm.

(Charge generation layer)
The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and additives as necessary.

  A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, CGM which can minimize the increase in residual potential due to repeated use has a crystal structure capable of taking a stable aggregate structure among a plurality of molecules, specifically, a phthalocyanine pigment having a specific crystal structure, CGM of a perylene pigment is mentioned. For example, CGM such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu-Kα ray and benzimidazole perylene having a maximum peak at 2θ of 12.4 has little deterioration due to repeated use. Potential increase can be reduced.

  When a binder resin is used as a dispersion medium for dispersing the charge generation material in the charge generation layer, a known resin can be used as the binder resin, and preferred resins include a formal resin, a butyral resin, a silicone resin, and a silicone-modified butyral. Examples thereof include resins and phenoxy resins. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably from 0.01 to 2 μm.

(Charge transport layer)
The charge transport layer contains a charge transport material (CTM) and a binder resin. Other substances may contain additives such as antioxidants as necessary.

  As the charge transport material (CTM), for example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a binder resin to form a layer. The thickness of the charge transport layer is preferably 10 to 40 μm.

  Examples of the binder resin used for the charge transport layer (CTL) include polystyrene-acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, Mention may be made of polycarbonate resins, silicone resins, melamine resins and copolymer resins containing two or more of the repeating unit structures of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.

  A polycarbonate resin is particularly preferable as the binder resin. The polycarbonate resin is particularly preferable in improving the dispersibility and electrophotographic characteristics of CTM. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The charge transport layer preferably contains an antioxidant. Typical examples of the antioxidants prevent or suppress the action of oxygen on auto-oxidizing substances existing in the photoreceptor or on the photoreceptor surface under light, heat, discharge, or the like. It is a substance with properties. As the antioxidant, a known one can be used, and examples thereof include 2,6-di-tert-butyl-4-methylphenol.

(Protective layer)
The outermost surface layer of the photoreceptor may be a charge transport layer, but a protective layer may be further provided thereon. The protective layer plays a role in maintaining the surface hardness of the photosensitive layer and preventing contamination due to adhesion of foreign matter. However, there is a photosensitive member that is not provided with a protective layer but is designed so that a layer present on the outermost surface of the photosensitive layer plays such a role.

  The protective layer contains inorganic particles. As the inorganic particles, particles of silica, alumina, titanium oxide, strontium titanate or the like are preferable.

  The protective layer contains a binder resin that helps dispersibility of the inorganic particles. As the binder resin, polycarbonate and polyarylate are preferable. The molecular weight of these polycarbonates and polyarylates is preferably 10,000 to 100,000.

  The ratio of the inorganic particles in the surface layer is preferably 5 to 50 parts by mass with respect to 100 parts by mass of the binder resin. More preferably, it is 6-30 mass parts. If the amount is less than 5 parts by mass, the surface layer is greatly worn, and scratches or the like are generated, so that the halftone image tends to be rough. When the amount is more than 50 parts by mass, the surface layer becomes a fragile film, and cracks and the like are likely to occur.

  The protective layer preferably contains a charge transport material. As the charge transport material (CTM), for example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. The mass ratio of the binder resin and the charge transport material in the protective layer is preferably 30 to 200 parts by mass, more preferably 50 to 150 parts by mass with respect to 100 parts by mass of the binder resin.

<Intermediate transfer belt>
The intermediate transfer belt is an endless belt having a volume resistance of 1 × 10 ⁶ to 1 × 10 ¹² Ω · cm. For example, polycarbonate (PC), polyimide (PI), polyamideimide (PAI), polyvinylidene fluoride (PVDF) , Conductive fillers such as carbon are dispersed in resin materials such as etafluoroethylene-ethylene copolymer (ETFE), and rubber materials such as EPDM, NBR, CR, and polyurethane, or ionic conductive materials are included. Used. The thickness of the intermediate transfer belt is preferably set to about 50 to 200 μm for a resin material and about 300 to 700 μm for a rubber material.

<Secondary transfer member>
As the secondary transfer member, a secondary transfer roller or a secondary transfer belt can be used.

In the secondary transfer roller, a conductive filler such as carbon is dispersed in a rubber material such as polyurethane, EPDM, or silicone, or an ionic conductive material is contained on the peripheral surface of a conductive core metal such as 8 mm stainless steel. A semiconductive elastic rubber having a thickness of 5 mm and a rubber hardness of about 20 to 70 ° (Asker-C) in a solid state or foamed sponge state with a volume resistance of about 1 × 10 ⁵ to 1 × 10 ⁹ Ω · cm. It is formed by coating.

  As the secondary transfer belt, a belt formed of the same material as the intermediate transfer belt can be used.

  Next, the cleaning means for each member to be cleaned will be described.

《Cleaning means》
<Photoconductor cleaning means>
FIG. 5 is a schematic view showing an example of the cleaning means for the photosensitive member.

In FIG. 5, the photosensitive member is represented by 1, and the cleaning blade contact angle is represented by θ ₁ . Free length L ₁ of the cleaning blade 16 is the length of the end cleaning blade assumed not deform from B of the blade holder 17 (in the drawing indicated by a dotted line) of the tip point A '. h ₁ indicates the thickness of the cleaning blade. The cleaning blade contact angle θ ₁ represents an angle formed between the tangent line X at the contact point A of the photosensitive member and the cleaning blade assumed not to be deformed. The amount of biting a is a radius r ₀ of the outer periphery S ₀ of the photosensitive member and a radius r ₁₁ of a circle S ₁₁ centered on the same central axis C as the photosensitive member having the tip A ′ of the cleaning blade assumed to be undeformed. It is a difference. Contact angle theta ₁ to the photosensitive member of the cleaning blade is preferably 5 to 35 °. By setting the contact angle within the above range, there is no cleaning failure of the transfer residual toner, and no cleaning blade curling occurs (the cleaning blade tip is moved from the counter direction in the same direction as the rotation direction of the photosensitive member). preferable.

<Cleaning means for intermediate transfer belt>
FIG. 6 is a schematic diagram illustrating an example of a cleaning unit for the intermediate transfer belt.

  In FIG. 6, reference numeral 601 denotes a casing which has a housing portion to which the members constituting the intermediate transfer belt cleaning device 190 </ b> A are attached and the toner removed from the intermediate transfer belt 6 is housed.

  Reference numeral 602 denotes a cleaning blade made of an elastic material such as urethane rubber, and is fixed to the blade holder 603 with an adhesive or the like.

  The blade holder 603 is rotatably attached to a support shaft 604 provided in the casing 601.

  A pressing spring 605 urges the blade holder 603 to rotate counterclockwise around the support shaft 604, and the tip of the cleaning blade 602 is in a direction opposite to the rotation direction of the intermediate transfer belt 6 (counter direction). In this state, the intermediate transfer belt 6 backed up by the backup roller 75 is disposed in pressure contact with the pressure contact position C.

  Reference numeral 608 denotes a toner guide member formed of a sponge roller. The toner guide member 608 is disposed on the intermediate transfer belt 6 upstream of the pressure contact position C between the cleaning blade 602 and the intermediate transfer belt 6 when viewed in the rotational direction indicated by the arrow of the intermediate transfer belt 6. It arrange | positions so that it may contact | abut.

  The sponge roller 608 is rotated in the same direction as the intermediate transfer belt 6 at a contact position with the intermediate transfer belt 6 by a rotating means (not shown), and the peripheral speed of the sponge roller 608 is higher than the peripheral speed of the intermediate transfer belt 6. It is configured to be faster.

  Reference numeral 609 denotes a toner discharge regulating member made of a PET sheet, one end of which is in contact with the surface of the sponge roller 608 at a position opposite to the position where the sponge roller 608 and the intermediate transfer belt 6 are in contact, and the other end. The sheet holding member 610 provided above the sponge roller 608 is fixed with a double-sided tape or the like.

  The sheet holding member 610 is fixed to the protrusion 611 of the casing 601 with a screw or the like.

  With such a configuration, the intermediate transfer belt 6, the cleaning blade 602, the sponge roller 608, and the toner discharge regulating member 609 form a space S.

  Reference numeral 612 denotes a collection screw provided at the bottom of the casing 601. The toner stored in the bottom of the casing 601 is transported in a direction perpendicular to the paper surface of the drawing and discharged outside the casing 601.

  As shown in the figure, reference numeral 613 denotes a toner receiving sheet made of PET having one end bonded to the bottom of the casing 601 facing the intermediate transfer belt 6 and the other end lightly contacting the intermediate transfer belt 6. Prevents falling down.

<Secondary transfer member cleaning means>
FIG. 7 is a schematic diagram illustrating an example of a cleaning unit for the secondary transfer member.

  The shape of the secondary transfer member of the secondary transfer member cleaning device 70 is not particularly limited, and either a roller shape or a belt shape can be used.

  FIG. 7A shows a cleaning unit using a secondary transfer roller 7A as a secondary transfer member.

  FIG. 7A shows a state in which the secondary transfer roller 7A is pressure-bonded to the backup roller 6B and the cleaning blade 71 is pressed to the secondary transfer roller 7A via the intermediate transfer belt 6.

  The secondary transfer member cleaning device 70 includes the secondary transfer roller 7A and its cleaning means 71, and the position of the rotary shaft 7C of the secondary transfer roller 7A and the cleaning holding portion 73H of the cleaning blade 71 in the cleaning means 71. The position of the rotation support shaft 73C and the position of the fixing pin 74P that fixes the other end of the spring 74 that is hooked at one end to the cleaning holding portion 73H are the positions of the housing of the secondary transfer member cleaning device 70. 72 is fixed.

  In the above-described embodiment, the spring 74 is formed as an elastic member, and one end thereof is fixed to the cleaning holding portion 73H and the other end is fixed to the housing 72.

  FIG. 7B shows a cleaning means for the secondary transfer member in which the secondary transfer roller 7A shown in FIG. 7A is changed to an endless belt 7D.

  7A and 7B, the cleaning blade 71 is made of urethane rubber, has a free length of 9 mm, a thickness of 2 mm, and a spring force of the spring 74 of 18.3 N / m. The contact pressure against the secondary transfer roller is set to 13.7 N / m.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.

<Production of toner>
The toner was prepared as follows.

<Preparation of toner particles (A)>
(Preparation of resin particle dispersion 1)
201 parts by mass of styrene, 117 parts by mass of butyl acrylate and 18.3 parts by mass of methacrylic acid were mixed, and this monomer mixture was heated to 80 ° C. while stirring, and 172 parts by mass of behenyl behenate was gradually added and dissolved. did.

  Next, a surfactant aqueous solution obtained by dissolving 3 parts by mass of the anionic surfactant “dodecylbenzenesulfonic acid” in 1182 parts by mass of pure water is heated to 80 ° C., the monomer solution is added, and high-speed stirring is performed. A monomer dispersion was prepared.

  Next, 867.5 parts by mass of pure water was put into a polymerization apparatus equipped with a stirrer, a cooling pipe, a temperature sensor, and a nitrogen introduction pipe, and the internal temperature was set to 80 ° C. while stirring under a nitrogen stream. The monomer dispersion was charged into this polymerization apparatus, and a polymerization initiator aqueous solution in which 8.55 parts by mass of potassium persulfate was dissolved in 162.5 parts by mass of pure water was added.

  After adding the polymerization initiator aqueous solution, 5.2 parts by mass of n-octyl mercaptan was added over 35 minutes, and polymerization was further performed at 80 ° C. for 2 hours. Furthermore, a polymerization initiator aqueous solution in which 9.96 parts by mass of potassium persulfate was dissolved in 189.3 parts by mass of pure water was added, and 366.1 parts by mass of styrene, 179.1 parts by mass of butyl acrylate, and n-octyl mercaptan. The monomer solution mixed with 2 parts by mass was added dropwise over 1 hour. After the monomer solution was dropped, the polymerization treatment was continued for 2 hours, and then cooled to room temperature to prepare “resin particle dispersion 1”.

(Preparation of resin particle dispersion for shell)
After adding 2948 parts by mass of pure water and 1 part by mass of the anionic surfactant “dodecylbenzenesulfonic acid” to a reactor equipped with a stirrer, a cooling tube, a nitrogen introduction tube, and a temperature sensor, Warm to 80 ° C under. Next, 520 parts by mass of styrene, 184 parts by mass of butyl acrylate, 96 parts by mass of methacrylic acid, 22.1 parts by mass of n-octyl mercaptan, and 10.2 parts by mass of potassium persulfate are added to 218 parts by mass of pure water. A dissolved polymerization initiator aqueous solution was prepared. After the polymerization initiator aqueous solution was charged into the reactor, the monomer mixed solution was dropped over 3 hours, and further polymerized for 1 hour, and then cooled to room temperature to prepare “resin particle dispersion for shell”. . The weight average molecular weight of the shell tree particles was 13,200, and the mass average particle diameter was 82 nm.

(Preparation of cyan colorant dispersion)
11.5 parts by mass of sodium n-dodecyl sulfate is dissolved in 1600 parts by mass of pure water, 25 parts by mass of “CI Pigment Blue 15: 3” is gradually added, and then “Clearmix W Motion CLM-0” is added. .8 (manufactured by M Technique Co., Ltd.) ”was used to prepare a“ cyan colorant dispersion ”having a median diameter of 153 nm on a number basis.

(Preparation of magenta colorant dispersion)
C.I. used in the preparation of the cyan colorant dispersion. I. A “magenta colorant dispersion” having a median diameter of 183 nm on a number basis was prepared in the same manner except that CI Pigment Blue 15: 3 was changed to “CI Pigment Red 122”.

(Preparation of yellow colorant dispersion)
C.I. used in the preparation of the cyan colorant dispersion. I. A “yellow colorant dispersion” having a median diameter of 177 nm on a number basis was prepared in the same manner except that CI Pigment Blue 15: 3 was changed to “CI Pigment Yellow 74”.

(Preparation of carbon black dispersion)
C.I. used in the preparation of the cyan colorant dispersion. I. A “carbon black dispersion” having a median diameter of 167 nm on a number basis was prepared in the same manner except that the pigment blue 15: 3 was changed to carbon black “Mogal L”.

(Production of toner particles (A) C1)
“Resin particle dispersion 1” prepared above was 357 parts by mass in terms of solid content, the particle dispersion of polyester ionomer resin “Finetex ES-2200” was 68 parts by mass in terms of solids, 900 parts by mass of ion-exchanged water, 200 parts by mass of the “cyan colorant dispersion” in terms of solid content was charged into a reaction apparatus equipped with a stirrer, a temperature sensor, and a cooling pipe. The temperature in the container was kept at 30 ° C., and a 5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH to 10.

Next, an aqueous solution in which 2 parts by mass of magnesium chloride hexahydrate is dissolved in 1000 parts by mass of ion-exchanged water is dropped over 10 minutes with stirring, and then the temperature is raised to 75 ° C. to aggregate and fuse the particles. I let you. The “Coulter Counter 3 (manufactured by Beckman Coulter)” was used as it was, and the heating and stirring were continued until the median diameter (D ₅₀ ) on the basis of the number became 5.3 μm.

When the median diameter (D ₅₀ ) on the basis of the number reaches 5.3 μm, 210 parts by mass of the “resin particle dispersion for shell” is added in terms of solid content and stirred for 1 hour to bring the particles for shell onto the surface. Fused. Further, stirring is continued for 30 minutes to completely form the shell, and then an aqueous sodium chloride solution in which 40 parts by mass of sodium chloride is dissolved in 500 parts by mass of ion-exchanged water is added, and the internal temperature is raised to 78 ° C. Stirring was continued for 1 hour and then cooled to room temperature (25 ° C.) to form particles. The generated particles were repeatedly washed with ion-exchanged water and then dried with hot air at 35 ° C. to produce “dried particles C1”.

  1% by weight of hydrophobic silica (number average primary particle size 12 nm, hydrophobization degree 68) and 1 mass of hydrophobic titanium oxide (number average primary particle size 20 nm, hydrophobization degree 64) are added to “dry particles C1”. % Was added. After performing a mixing process using a Henschel mixer (manufactured by Mitsui Miike Chemical Co., Ltd.), coarse particles were removed using a sieve having an opening of 45 μm to produce “toner particles (A) C1”.

The median diameter (D ₅₀ ) based on the number of toner particles (A) C1 obtained was measured using “Coulter Counter 3 (manufactured by Beckman Coulter)” to be 5.5 μm. Further, the circularity of the particles was measured by “FPIA2000 (manufactured by Systex)” and found to be 0.97.

(Production of toner particles (A) C2 to C5)
“Toner particles (A) C2 to C5” were prepared in the same manner except that the aggregation / fusion conditions were changed in the production of toner particles (A) C1.

(Production of toner particles (A) M1 to M5)
“Toner particles (A) M1 to M5” were prepared in the same manner except that the cyan colorant dispersion used in the production of toner particles (A) C1 to C5 was changed to “magenta colorant dispersion”.

(Production of toner particles (A) Y1 to Y5)
“Toner particles (A) Y1 to Y5” were prepared in the same manner except that the cyan colorant dispersion used in the production of toner particles (A) C1 to C5 was changed to “yellow colorant dispersion”.

(Production of toner particles (A) K1 to K5)
“Toner particles (A) K1 to K5” were prepared in the same manner except that the cyan colorant dispersion used in the preparation of toner particles (A) C1 to C5 was changed to “carbon black dispersion”.

Table 1, median diameter _{(D 50)} in the number-based "Toner particles (A) C1 to C5" refers to a circularity.

(Production of toner particles (A) C6)
100 parts by weight of polyester resin, 3.5 parts by weight of “CI Pigment Blue 15: 3”, 2 parts by weight of zinc salicylate (charge control agent), and 5 parts by weight of carnauba wax were sufficiently obtained using a Henschel mixer. After mixing, the mixed material is thoroughly kneaded using a continuous twin screw extruder “KTK type twin screw extruder manufactured by Kobe Steel, Ltd.”, cooled, coarsely pulverized using a hammer mill, Finely pulverized by the used fine pulverizer and classified by a classifier using a swirling airflow to obtain particles. The particles were spheroidized with the circularity control device shown in FIG. 3 to produce “toner particles (A) C6”.

The median diameter (D ₅₀ ) on the basis of the number of toner particles (A) C6 was measured using “Coulter Counter 3 (manufactured by Beckman Coulter)” to be 5.5 μm. Further, the circularity of the toner particles (A) C6 was measured by “FPIA2000 (manufactured by Systex)” and found to be 0.94.

(Production of toner particles (A) M6)
Toner particles (A) C.3 used in the production of C6. I. “Toner Particles (A) M6” was prepared in the same manner except that CI Pigment Blue 15: 3 was changed to “CI Pigment Red 122”.

(Production of toner particles (A) Y6)
Toner particles (A) C.3 used in the production of C6. I. “Toner particles (A) Y6” was prepared in the same manner except that CI Pigment Blue 15: 3 was changed to “CI Pigment Yellow 74”.

(Production of toner particles (A) K6)
Toner particles (A) C.3 used in the production of C6. I. “Toner particles (A) K6” were prepared in the same manner except that Pigment Blue 15: 3 was changed to “Mogal L”.

Table 1 shows the median diameter (D ₅₀ ) and circularity on the basis of the number of toner particles (A) C1 to C6.

In addition, the median diameter (D ₅₀ ) on the basis of the circularity and the number is a value obtained by measurement by the above method.

"Toner particles (A) M1-M6" median diameter _{(D 50)} in the number-based "Toner particles (A) Y1 to Y6" and "Toner particles (A) K1-K6", circularity of "Toner particles ( A) C1 to C6 ”are the same, and will be omitted.

<Preparation of resin particles (B)>
(Preparation of resin particles (B) 1)
The polyethylene resin powder was pulverized with a mechanical pulverizer and then classified to prepare “resin particles (B) 1” having a median diameter (D ₅₀ ) of 2.0 μm and a circularity of 0.80 based on the number.

(Production of resin particles (B) 2 to 7)
“Resin particles (B) 2 to 7” were produced by changing the pulverization and classification conditions during the production of the resin particles (B) 1.

(Preparation of resin particles (B) 8)
Acrylic / styrene resin powder is pulverized with a mechanical pulverizer and then classified to produce “resin particles (B) 8” having a median diameter (D ₅₀ ) of 2.0 μm and a circularity of 0.80. did.

Table 2 shows the median diameter (D ₅₀ ) and circularity in terms of the number of “resin particles (B) 1 to 8”.

In addition, the median diameter (D ₅₀ ) and circularity on the basis of the number are values obtained by measurement by the above method.

<Production of toner>
The toner particles (A) and resin particles (B) prepared above were blended in the proportions shown in Table 3, and the Henschel mixer (made by Mitsui Miike Mining Co., Ltd.) was used. “Toners C1 to C15” were prepared by mixing at a speed of 40 m / s for 5 minutes.

Table 3 shows the toner particles of the toner was produced (A) The amount of the resin particle (B), a _{D 50} / toner _{D 50} of the particles (A) of the resin particles (B).

  “Toners M1 to M15”, “Toners Y1 to Y15”, and “Toners K1 to K15” were prepared in the same manner as “Toners C1 to C15”.

<< Preparation of developer >>
Each of the color toners (A) prepared above and a carrier having an average particle diameter of 35 μm obtained by coating a ferrite particle with a styrene acrylic resin were mixed so that the toner concentration would be 8% by mass. Agents 1-15 "were prepared.

<< Production of photoconductor >>
The photoconductor was produced as follows.

<Preparation of Photoreceptor 1>
(Conductive support)
As the conductive support, an aluminum drum subjected to Compaq processing was prepared.

(Middle layer)
An intermediate layer coating solution was prepared by dissolving the following composition. An intermediate layer coating solution was applied on the prepared conductive support by a dipping method to form an intermediate layer coating film. Then, it dried for 30 minutes at 100 degreeC, and formed the intermediate | middle layer whose film thickness is 1.0 micrometer.

Ethylene-vinyl acetate copolymer “ELBACS 4260” (Mitsui DuPont Chemical Co., Ltd.) 50 parts by mass Toluene / n-butyl alcohol = 5/1 (mass ratio) 2000 parts by mass (charge generation layer)
The following composition was dispersed using a sand mill for 17 hours to prepare a charge generation layer coating solution. A charge generation layer coating film was formed by applying a coating solution for charge generation layer on the intermediate layer by a dipping method. Then, it dried at 100 degreeC for 30 minutes, and formed the charge generation layer with a film thickness of 1.5 micrometers.

Titanylphthalocyanine “CGM-1” (having strong peaks at 9.5 °, 15.0 °, 24.1 ° and 27.3 ° of the Bragg angle (2θ ± 0.2 °) in the characteristic X-ray diffraction of CuKα Oxytitanium phthalocyanine) 100 parts by mass Silicone resin (KR-5240: manufactured by Shin-Etsu Chemical Co., Ltd.) 100 parts by mass t-butyl acetate 1000 parts by mass (charge transport layer)
The following composition was dissolved to prepare a coating solution for a charge transport layer. A charge transport layer coating film was formed by dip coating a charge transport layer coating solution on the charge generation layer. Thereafter, the film was dried at 110 ° C. for 60 minutes to form a charge transport layer having a thickness of 23 μm.

CTM-1 500 parts by weight Polycarbonate (Z-200: manufactured by Mitsubishi Gas Chemical Company) 560 parts by weight Dioxolane (bp 74 to 75 ° C.) 2800 parts by weight Methyl phenyl silicone oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.)
100ppm added to the total solid content

(Protective layer)
Inorganic particles: silica particles (primary treatment: dimethyldichlorosilane, secondary treatment: silica with an average primary particle size of 50 nm surface-treated with hexamethyldisilazane) 30 parts by mass Charge transport material (N- (4-methylphenyl)- N- {4- (β-phenylstyryl) phenyl} -p-toluidine) 150 parts by weight Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts by weight Antioxidant (Irganox 1010: manufactured by Ciba Geigy Japan) 12 parts by weight Tetrahydrofuran: THF 2800 parts by mass Silicone oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 4 parts by mass were mixed, dispersed and dissolved to prepare a surface protective layer coating solution. This coating solution is applied onto the charge transport layer with a circular slide hopper type coating machine, and dried at 110 ° C. for 70 minutes to form a surface protective layer 1 having a dry film thickness of 6.0 μm. Was made.

<Preparation of Photoreceptor 2>
The protective layer formed in the preparation of the photoreceptor 1 is not formed, but the one stopped by the charge transport layer is referred to as “photoreceptor 2”.

《Preparing the cleaning blade》
As the cleaning blade, the following cleaning blade made of urethane rubber was prepared.

Cleaning blade 1: rebound resilience 35%, free length 8mm, thickness 5mm
Cleaning blade 2: Rebound resilience 35%, free length 12 mm, thickness 5 mm
Cleaning blade 3: Rebound resilience 60%, free length 8mm, thickness 5mm
Cleaning blade 4: Rebound resilience 60%, free length 12 mm, thickness 5 mm
Cleaning blade 5: rebound resilience 30%, free length 6 mm, thickness 5 mm
Cleaning blade 6: Rebound resilience 65%, free length 14 mm, thickness 5 mm
<Evaluation>
As an image forming apparatus for evaluation, a commercially available digital printer “bizhub Pro C500 (manufactured by Konica Minolta Business Technologies Co., Ltd.)” having a cleaning process using a cleaning blade is incorporated in a patch image detection sensor shown in FIG. 1) to which a cleaning means for cleaning the secondary transfer member shown in FIG.

  The above-prepared and prepared toner, developer, photoreceptor, and cleaning blade are sequentially loaded and mounted on the image forming apparatus, and a character image with a printing rate of 10% is printed in A4 size in a printing environment of 20 ° C. and 50% RH. 400,000 sheets were printed on high quality paper.

  The size of the patch image was 15 mm × 15 mm for all four colors, and the patch image was formed every 1000 sheets printed. The patch image toner was set to be transferred from the intermediate transfer belt to the secondary transfer member.

  Table 4 shows the setting conditions of the toner, photoconductor, cleaning blade, and cleaning blade used in the evaluation.

<Toner slip-through>
After completion of printing 400,000 sheets, a character image and a patch image with a printing rate of 10% are formed in a printing environment of 20 ° C. and 50% RH. The image portion toner cleaning property was evaluated by visually observing the surface of the secondary transfer member.

Evaluation criteria A: Good without occurrence of toner slipping ○: Toner slipping is slightly observed, but there is no practical problem ×: Toner slipping occurs and there is a practical problem.

<Black line>
As for the streaks due to toner slipping, a black halftone image (image density 0.04) was formed, and the degree of black streaks generated on the halftone image was visually evaluated.

Evaluation criteria ◎: No black streak on halftone image ○: Slight black streak is seen on halftone image but no problem in use ×: Black streak can be confirmed on halftone image Unacceptable level Table 5 shows the evaluation results.

  From the evaluation results of Table 5, it can be seen that "Examples 1 to 15" of the present invention are satisfactory for all evaluation items. On the other hand, it can be seen that “Comparative Examples 1 to 10” of the present invention has a problem in any of the evaluation items, and the object of the present invention cannot be achieved.

It is a schematic diagram which shows the main parameters of a cleaning blade. FIG. 4 is a schematic view showing a state where small particles (B) form a damming portion in the nip portion of the cleaning blade, and toner particles (A) are dammed by the damming portion. It is the schematic which shows an example of the circularity control apparatus which controls the circularity of a toner particle (A). 1 is a schematic cross-sectional view showing an example of a color image forming apparatus having a cleaning means using a cleaning blade. It is the schematic which shows an example of the cleaning means of a photoconductor. FIG. 5 is a schematic diagram illustrating an example of a cleaning unit for an intermediate transfer belt. It is the schematic which shows an example of the cleaning means of a secondary transfer member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device 3 Exposure optical system 4 Developing device 6 Intermediate transfer belt 7 Primary transfer roller 7A Secondary transfer roller 8 Detection sensor 17 Fixing device 190 Photoconductor cleaning device 190A Intermediate transfer belt cleaning device 70 Secondary transfer member cleaning apparatus

Claims (3)

After transferring the toner image formed on the photoconductor to a transfer material, the toner remaining on the photoconductor, intermediate transfer belt, or secondary transfer member is cleaned with a cleaning blade. In the forming method,
The toner comprises toner particles (A) and resin particles (B),
The toner particles (A) have a circularity of 0.930 to 0.990, and a median diameter (D ₅₀ ) based on the number is 3.0 to 8.0 μm.
The circularity of the resin particles (B) is from 0.70 to 0.92, median diameter number-based median diameter _{(D 50)} toner particles (A) in the number-based _{(D 50) 0.15~0.} 60 times,
The rebound resilience of the cleaning blade is 35-60%, the free length is 8-12 mm,
The cleaning blade is contacted in the counter direction with respect to the rotation direction of the member to be cleaned, the contact angle for contact with the member to be cleaned is 15 to 30 degrees, and the contact pressure is 10 to 40 N / m. An image forming method. 2. The image forming method according to claim 1, wherein the toner contains 0.05 to 5.0 parts by mass of resin particles (B) with respect to 100 parts by mass of toner particles (A). The photoconductor is formed by laminating a charge generation layer and a plurality of charge transport layers on a conductive support, and among the plurality of charge transport layers, the charge transport layer forming the outermost surface layer of the photoconductor contains inorganic particles. The image forming method according to claim 1, wherein:

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