JP2002072804A - Image forming device and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device and an image forming method which assure excellent cleaning property of a latent image carrier without lowering image quality and independent of using temperature environment even in the image forming device using spherical toner, at a low cost. SOLUTION: The image forming device is provided with an image carriers 10, a latent image forming means 13 for forming a latent image on a surface of the image carrier 10, a developing means 14 for forming a toner image by developing the formed latent image by the toner, a transfer means 15 for transferring the formed toner image onto a transferring body and a cleaning means 16 provided with a cleaning blade 19 for removing residual toner left on a surface of the image carriers 10 after transfer. The image forming device and the image forming method are distinguished by that the toner consists of at least toner particles having average shape factor SF within the range of 100 to 135 and an external additive having 50 to 500 nm average grain size and the cleaning blade 19 is made of an elastic body having >=35% impact resilience at 10 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and an image forming method using an electrophotographic system, such as a copying machine, a facsimile, and a printer.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic method, an electrostatic latent image formed by charging and exposing an image carrier surface is developed with a colored toner to form a toner image as a visible image, and the toner image is formed. An image is formed by transferring the image onto a transfer medium such as a transfer paper and fixing the image with a hot roll or the like. Generally, untransferred toner remains on the surface of the image carrier after the transfer of the toner image. Therefore, it is necessary to remove the residual toner by some cleaning means prior to the next image forming process.
In general, other foreign substances adhering to the surface of the image carrier are removed together with the residual toner by a cleaning unit.

As a cleaning means for removing the residual toner and the like after the transfer, various methods such as a method using a fur brush, a magnetic brush, and a method using a cleaning blade made of an elastic material are used. However, means for scraping off the toner by rubbing the image carrier with a cleaning blade is generally used because of its low cost and high performance stability. As an elastic body used as a material of the cleaning blade, polyurethane rubber is often used because of its excellent wear resistance.

On the other hand, in recent years, in particular, in a full-color image forming apparatus, high image quality has been advanced, and as one direction for the high image quality, a toner having a small diameter and a spherical shape has been advanced. By reducing the diameter, the reproducibility of the dots of the toner image formed on the surface of the image carrier can be improved, and by making the particles spherical, the developability and transferability can be improved.

However, the small-diameter, spherical toner described above (hereinafter, may be referred to as "spherical toner").
, Especially in the blade cleaning method,
There may be a problem that good cleaning performance cannot be obtained. The toner that has caused the cleaning failure becomes an image quality defect at the time of the next image formation.Especially when the charging device is a contact type charger such as a roll charger, the toner that has passed through the cleaning blade is deposited on the charger and causes charging failure. In some cases, the effect is large. In particular, in the case of a substantially spherical toner having a toner shape index SF smaller than 125, the cleaning property is significantly deteriorated. Even a toner having a shape index SF between 125 and 135 has a shape distribution, so that a substantially spherical toner exists and the cleaning property tends to deteriorate over time.

[0006] The cleaning property tends to deteriorate as the particle size of the toner used for development decreases. The image forming apparatus is used in a temperature range of about 10 ° C. to 30 ° C., and especially at a low temperature, the deterioration of the cleaning property becomes remarkable.

In the cleaning method using the cleaning blade, the toner is scraped off by rubbing the image carrier with the rubber blade as described above. The edge tip is deformed, forming a minute wedge-shaped space between the two. In this space, the smaller the diameter of the toner is, the more easily the toner enters the edge tip, and the toner that has entered the edge tip is hard to be replaced, and forms a non-flow area.

[0008] Further, spherical toner is more likely to be packed closest than irregular toner, so that it is likely to be compacted in a minute space near the contact point between the edge of the cleaning blade and the image carrier. In a state where the frictional resistance between the toner in the non-flow area and the image carrier is relatively small and the toner is slipping on the image carrier, no cleaning failure occurs, but the external additive due to the rubbing with the image carrier. When the frictional force between the toner and the image carrier increases due to separation of the toner, the spherical toner starts to roll between the cleaning blade and the image carrier and slips through because the rolling friction is smaller than that of the conventional crushed irregular-shaped toner. Conceivable.

In order to prevent defective cleaning of the cleaning blade in an image forming apparatus using spherical toner, a method of forming an image using a mixture of spherical toner and irregular toner is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-1985. 1315
No. 47, Japanese Unexamined Patent Publication No. 6-148941, and the like. However, in this method, a mixture of a spherical toner and an irregular toner is used as a toner for development, so that a dense and uniform image or a spherical toner can be obtained as compared with a case where only a spherical toner is developed. There is a disadvantage that high transfer efficiency, which is an advantage, cannot be obtained.

Japanese Patent Application Laid-Open No. 08-254873 discloses an image forming apparatus including a plurality of developing machines for developing images of different colors, wherein at least one developing machine contains an irregular toner. It has been proposed to store spherical toner in other developing machines. Also in this method, the image developed by the developing device containing the irregular toner is an advantage of the dense and uniform image and the spherical toner as compared with the case where the image is developed by the developing device containing only the other spherical toner. There is a problem that high transfer efficiency cannot be obtained. Further, in a tandem type full-color image forming apparatus, the effect cannot be exhibited.

As another means for preventing defective cleaning of a cleaning blade in an image forming apparatus using a spherical toner, a method of supplying a lubricant or the like to an image bearing member has been proposed (see, for example, Japanese Patent Application Laid-Open No. H05-1993). No. 188643). However, if the supply of lubricant to the image carrier is insufficient, cleaning failure occurs, and if the supply is excessive, adverse effects due to filming on the image carrier are likely to occur. Therefore, it is necessary to supply the lubricant uniformly to the image carrier over a long period of time. There is
Design is very difficult. In recent years, the size of the apparatus has been reduced. Particularly in an image forming apparatus using an image carrier having a small diameter, it is not possible to secure a space for a lubricant supply device for directly supplying a lubricant to the surface of the image carrier. Very difficult.
Particularly, in a tandem type image forming apparatus, each image carrier needs to be provided with a lubricant supply device, which is very disadvantageous in terms of cost reduction.

Accordingly, the present invention provides
The present invention has been made in view of the above-described circumstances in the related art. That is, an object of the present invention is to provide an image forming apparatus and an image forming method which ensure good cleaning performance of an image carrier regardless of a use temperature environment without deteriorating image quality even in an image forming apparatus using spherical toner. It is to provide at low cost.

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, by combining an external additive of a specific size with a cleaning blade of a specific physical property, The inventors have found that the above objects can be achieved, and have completed the present invention.

That is, an image forming apparatus according to the present invention comprises an image carrier, a latent image forming means for forming a latent image on the surface of the image carrier, and a toner for forming the latent image formed on the surface of the image carrier. Developing means for developing a toner image by developing the toner image, transfer means for transferring the toner image formed on the surface of the image carrier to a transfer-receiving body, and cleaning for removing residual toner on the surface of the image carrier body after the transfer. Cleaning means provided with a blade, the image forming apparatus, wherein the toner,
At least an average shape index SF represented by the following formula (1)
Is comprised of toner particles having a particle diameter of 100 to 135, and an external additive having an average particle diameter of 50 to 500 nm. The cleaning blade provided in the cleaning means is made of an elastic material having a rebound resilience at 10 ° C. of 35% or more. It is characterized by becoming. SF = 100 × πML ² / 4A Formula (1) ML: Absolute maximum length of toner particles A: Projected area of toner particles

Further, the image forming method of the present invention includes a latent image forming step of forming a latent image on the surface of the image carrier, and developing the latent image formed on the surface of the image carrier with toner. A developing step of forming a toner image formed on the surface of the image carrier, a transfer step of transferring the toner image to a transfer target body, and a cleaning step of removing residual toner on the surface of the image carrier after transfer by a cleaning blade. An image forming method comprising: wherein the toner has at least the formula (1)
And an external additive having an average particle size of 50 to 500 nm. The cleaning blade of the cleaning means has a rebound resilience at 10 ° C. of 35%. It is characterized by being made of the above elastic body.

In the present invention, the external additive is preferably spherical silica.
The content is preferably in the range of 0.5 to 5 parts by weight based on 100 parts by weight of the toner particles. The linear pressure of the cleaning blade pressed against the image carrier is 9.8 × 10 ⁻³ to
4.9 × 10 ^-2 N / mm (1.0 to 5.0 gf / mm)
It is preferable that

The material of the cleaning blade is preferably a polyurethane resin. The average shape index SF of the toner particles in the toner represented by the above formula (1) is preferably in the range of 100 to 125.

As described above, the reason why the cleaning property of the spherical toner is more difficult than that of the conventional amorphous toner is as follows.
Spherical toner with a low rolling friction coefficient is caused by rolling between the cleaning blade and the image carrier, and in order to improve the cleaning performance of the spherical toner, over a long period of time, regardless of the use environment, It is important how to stably suppress the rolling of the spherical toner.

As a means for stably suppressing the rolling of the spherical toner at the minute deformation portion at the tip of the cleaning blade for a long period of time, the present inventors have proposed that the toner has an outer diameter larger than that of a general external additive. The present inventors have found that a combination of adding an additive and setting the rebound resilience of the cleaning blade to 35% or more at a temperature of 10 ° C. is effective, and arrived at the present invention.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described first with respect to a toner and a cleaning blade which are characteristic of the present invention, and then the overall configuration of an image forming apparatus and an image forming method of the present invention will be described.

<Toner> The toner used in the present invention comprises toner particles comprising at least a binder resin and a colorant, and an external additive. The toner may be used alone as a one-component developer constituting a developer, but is generally used as a two-component developer mixed with a carrier to constitute a developer. Is done. Hereinafter, the toner used in the present invention and the carrier used as a mixture with the toner will be described in detail for each component.

(Toner Particles) The toner particles used in the present invention have an average shape index S represented by the following formula (1).
F is 100 to 135. SF = 100 × πML ² / 4A Formula (1) ML: Absolute maximum length of toner particles A: Projected area of toner particles For the toner particles having such a shape, there is a problem of rolling at the minute deformation portion at the tip of the cleaning blade. According to the image forming apparatus or the image forming method of the present invention, residual toner when such toner is used can be removed very effectively.

The average shape index SF refers to an arithmetic mean obtained by calculating the shape index SF of the toner particles according to the above equation (1). For example, the toner is sampled and an image analyzer (Luzex III, ( The analysis was performed on 100 toner particles, the circle equivalent diameter of each toner particle was measured, and the shape index SF of each toner particle was determined from the absolute maximum length and the projected area.
And calculating the arithmetic average thereof. The shape index SF is 100 for a true sphere.

The average shape index SF is 100 to
By using 125, higher developability and transferability can be ensured, and a high-quality image can be obtained.

The toner particles are composed of at least a binder resin and a colorant, and contain a releasing agent and other components as necessary. Examples of the binder resin of the toner particles include styrenes such as styrene and chlorostyrene; ethylene, propylene,
Monoolefins such as butylene and isoprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate; methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, acrylic acid Α-methylene aliphatic monocarboxylic esters such as phenyl, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether;
Homopolymers and copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone; and particularly typical binder resins include polystyrene and styrene-alkyl acrylate. Copolymers, styrene-alkyl methacrylate copolymers, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, styrene-maleic anhydride copolymers, polyethylene, polypropylene and the like can be mentioned. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like can be mentioned.

Examples of colorants for toner particles include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, and malachite. Green oxalate, lamp black, rose bengal, C.I. I. Pigment Red 4
8: 1, C.I. I. Pigment Red 122, C.I. I.
Pigment Red 57: 1, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 17, C.I.
I. Pigment Yellow 74, C.I. I. Pigment
Yellow 180, C.I. I. Pigment Blue 15:
1, C.I. I. Pigment Blue 15: 3 and the like can be exemplified as typical ones.

Examples of the release agent that can be contained in the toner particles include low molecular polyethylene, low molecular polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, candelilla wax and the like. be able to.

Further, a charge control agent may be added to the toner particles as needed. As the charge control agent, known ones can be used, and an azo-based metal complex compound, a metal complex compound of salicylic acid, and a resin-type charge control agent containing a polar group can be used. When toner particles are manufactured by a wet manufacturing method, it is preferable to use a material that is hardly soluble in water, in terms of controlling ionic strength and reducing wastewater contamination.

The toner particles usable in the present invention may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material. The volume average particle diameter of the toner particles that can be used in the present invention is preferably in the range of 2 to 9 μm, and more preferably in the range of 3 to 7 μm.

The method for producing the toner particles which can be preferably used in the present invention is not particularly limited as long as it satisfies the above-mentioned shape index and particle diameter. Can be. For the production of toner particles, for example, a binder resin and a colorant, a release agent as needed,
A kneading and pulverizing method for kneading, pulverizing and classifying a charge controlling agent and the like; a method of changing the shape of particles obtained by the kneading and pulverizing method by mechanical impact force or thermal energy; Emulsion polymerization and aggregation method in which a dispersion liquid formed by emulsion polymerization and a dispersion liquid such as a colorant, a releasing agent, and a charge control agent are mixed, aggregated, and heated and fused to obtain toner particles;
A suspension polymerization method in which a solution of a polymerizable monomer and a colorant to obtain a binder resin, and, if necessary, a solution of a release agent, a charge control agent, and the like is suspended in an aqueous solvent and polymerized; Dissolving suspension method in which a solution of an agent, a release agent, and, if necessary, a charge controlling agent is suspended in an aqueous solvent and granulated. Further, a production method may be performed in which the toner particles obtained by the above method are used as a core, and aggregated particles are further adhered and fused to form a core-shell structure.

(External Additive) In the image forming apparatus and the image forming method of the present invention, it is essential that the toner contains, as at least one of the external additives, particles having a size in the range of 50 to 500 nm. . An external additive having an average particle diameter of 50 to 500 nm contained in the toner (hereinafter, sometimes referred to as a “large-diameter external additive”) is deposited (sealed) on a minutely deformed portion at the tip of the cleaning blade, thereby being effective. In addition, the toner particles are prevented from entering the deformed portion at the edge tip of the cleaning blade, and at the same time, the large-diameter external additive is used as a lubricant to suppress the increase in the amount of deformation of the edge of the cleaning blade and to suppress stick and slip, thereby suppressing the toner compaction. And
Rolling of toner particles can be suppressed. By the above operation, the toner particles are prevented from slipping between the image carrier and the cleaning blade, and the cleaning property is remarkably improved.

In order to easily supply particles having an average particle diameter of 50 to 500 nm to the tip of the cleaning blade, it is most effective to add and adhere to the toner as an external additive, and to stably clean the cleaning blade. It is effective to carry the toner to the edge of the cleaning blade while holding it on the surface of the toner particles. The external additive held on the surface of the toner particles is separated from the surface of the toner particles by the stress of the rubbing with the cleaning blade, and is effectively supplied to the tip deformation portion of the cleaning blade.

If the average particle diameter of the large-diameter external additive is smaller than 50 nm, it is difficult for the large-diameter external additive to remain at the tip deformed portion of the cleaning blade, so that an effective seal cannot be formed. On the other hand, if it is larger than 500 nm, it is difficult to adhere to the surface of the toner particles, easily detached from the surface of the toner particles due to stirring stress in the developing device, and cannot be effectively supplied to the cleaning blade, and is stable for a long time. Therefore, the sealing effect and the cleaning blade behavior stabilizing effect cannot be exhibited. The average diameter of the large-diameter external additive is 80 to 300 n.
More preferably, it is within the range of m.

The specific gravity of the large-diameter external additive is 1.3 to 1.
It is preferably within the range of 9. If the specific gravity is larger than 1.9, the external additive is likely to be peeled off from the toner particles due to the stress in the developing machine, and it may not be possible to supply the external additive to the cleaning blade effectively. on the other hand,
When the specific gravity is less than 1.3, the large-diameter external additive is liable to coagulate and disperse, resulting in non-uniform earing of the large-diameter external additive.
Since the stress is selectively applied to the protruding portion, the large-diameter external additive is accelerated from being peeled off from the toner particles, and may not be effectively supplied to the cleaning blade.

The large-diameter external additive is desirably spherical. Since the large-diameter external additive is spherical, it can be uniformly dispersed on the surface of the toner particles, and peeling of the large-diameter external additive can be effectively suppressed. The definition of a sphere is Wade
11 can be discussed with the true degree of sphericity, and the degree of sphericity is 0.6
It is preferably at least 0.8, and more preferably at least 0.8.

It is considered that the effect of the large-diameter external additive is enhanced as the large-diameter external additive is more monodispersed. Here, the definition of the monodispersion can be discussed in terms of the standard deviation with respect to the average particle size including the aggregate, and the standard deviation is defined as D ₅₀
× 0.22 or less is desirable.

The content of the large-diameter external additive is preferably 0.5 to 5 parts by weight, more preferably 1 to 3 parts by weight, per 100 parts by weight of the toner particles. 0.5
If the amount is less than 5 parts by weight, the effect of improving the cleaning property of the spherical toner may not be sufficiently obtained, and if the amount is more than 5 parts by weight, the large-diameter external additive is filmed on the image carrier, and the image quality tends to deteriorate, Each is not preferred.

The material of the large-diameter external additive is not particularly limited as long as it has the above-mentioned shape, but silica is considered to be particularly good. This is because silica has a refractive index of 1.5
The reason is that even if the particle size is increased, the transparency is not reduced due to light scattering, and particularly, the PE value (index of light transmittance) at the time of forming an image on an OHP is not affected.

A general fumed silica has a specific gravity of 2.2.
In terms of particle size, the maximum is 50 nm from the viewpoint of production. Although the particle size can be increased as an aggregate, uniform dispersion is difficult, and a stable sealing effect cannot be obtained. On the other hand, other typical inorganic fine particles include titanium oxide (specific gravity 4.2, refractive index 2.6), alumina (specific gravity 4.0, refractive index 1.8), and zinc oxide (specific gravity 5.6, refractive index). Rate of 2.0), but in any case, when the particle diameter is larger than 50 nm, the toner particles are peeled off from the toner particles so that the sealing effect at the edge tip deformed portion of the cleaning blade is effectively exhibited. May be more likely to occur. Further, since the refractive index is high, it is disadvantageous for producing a color image.

Silica suitable as a large-diameter external additive, particularly spherical monodispersed silica having a specific gravity of 1.3 to 1.9, can be obtained by a sol-gel method which is a wet method. According to this method, the specific gravity can be controlled to be lower than that of the vapor phase oxidation method or the like, because the method is a production method using a wet method and without firing. Further, the specific gravity can be further adjusted by controlling the kind of the hydrophobizing agent or the amount of the hydrophobizing agent in the hydrophobizing process. Silica particle size, hydrolysis in the sol-gel method, alkoxysilane in the condensation polymerization step,
It can be freely controlled by the weight ratio of ammonia, alcohol and water, reaction temperature, stirring speed and supply speed. Monodisperse, spherical silica can also be achieved by manufacturing by a sol-gel method.

A specific method for producing silica is as follows. First, a silane compound such as tetramethoxysilane is dropped and stirred in the presence of water and an alcohol while applying a temperature using ammonia water as a catalyst. Next, centrifugation of the silica sol suspension generated by the reaction is performed,
Separate into wet silica gel, alcohol and aqueous ammonia. A solvent is added to the wet silica gel to make it into a silica sol state again, and a hydrophobizing agent is added to hydrophobize the silica surface. As the hydrophobizing agent, a general silane compound can be used. Next, the target monodispersed silica can be obtained by removing the solvent from the hydrophobized silica sol, drying and sieving. Further, the silica thus obtained may be subjected to the sol-gel treatment again as described above.

As the silane compound, those which are water-soluble can be used. As such a silane compound, a chemical structural formula R _a SiX _4-a (where a is an integer of 0 to 3;
Represents a hydrogen atom, an organic group such as an alkyl group and an alkenyl group, and X represents a hydrolyzable group such as a chlorine atom, a methoxy group and an ethoxy group. ) Can be used, and any type of chlorosilane, alkoxysilane, silazane, and special silylating agent can be used. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyl Triethoxysilane, dimethyldiethoxysilane,
Phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N-bis (trimethylsilyl) urea, tert-butyldimethylchlorosilane , Vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-
Glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane and the like can be exemplified as typical examples.

As the above-mentioned hydrophobizing agent, particularly preferred are dimethyldimethoxysilane, hexamethyldisilazane, methyltrimethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane and the like.

In the image forming apparatus and the image forming method of the present invention, in addition to the large-diameter external additives described above,
An inorganic compound for controlling the fluidity and chargeability of the toner can be contained in the toner. In order to control the fluidity and chargeability of the toner, it is necessary to sufficiently coat the surface of the toner particles with an external additive, but it is not possible to obtain a sufficient coating with the large-diameter external additive. Therefore, it is desirable to use a small-diameter inorganic compound together with the large-diameter external additive.

As the small-diameter inorganic compound that can be contained in the toner, known compounds can be used. For example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, oxide Zinc, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, red iron oxide, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride, calcium carbonate, magnesium carbonate, calcium phosphate And the like. The surface of these inorganic fine particles may be subjected to a known surface treatment depending on the purpose.

The average particle diameter of the inorganic compound having such a small diameter that can be contained in the toner is preferably less than 50 nm, more preferably in the range of 5 to 30 nm. In addition, the amount of the toner
It is preferable that the amount be in the range of 0.3 to 3.0 parts by weight with respect to parts by weight.

(Carrier) As a carrier used together with the above-mentioned toner, as a core material, a magnetic metal such as iron, nickel and cobalt; a magnetic oxide such as ferrite and magnetite; a glass bead; In order to adjust the volume resistivity using the method, a magnetic material is preferable. The average particle size of the core material is usually 10
５００500 μm, preferably 30-100 μm
m.

Further, these carriers preferably have a resin coating layer coated with a resin or the like in order to impart charging properties. Examples of the resin include polyethylene, polypropylene, polystyrene, polyacrylonitrile, and the like.
Straight silicone resin consisting of polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, or organosiloxane bond or its modification Products, fluororesin, polyester, polyurethane, polycarbonate, phenolic resin, amino resin, melamine resin, benzoguanamine resin, urea resin, amide resin, epoxy resin, etc., but are not limited thereto.

The method for forming the resin coating layer on the surface of the core material of the carrier includes a dipping method in which the core material is dipped in a solution for forming the coating layer, a spray method in which the solution for forming the coating layer is sprayed on the surface of the core material, and a core method. The fluidized bed method of spraying the coating layer forming solution while the material is suspended by flowing air, the kneader coater method of mixing the core material and the coating layer forming solution in a kneader coater and then removing the solvent are applied. can do.

In the present invention, the mixing ratio (weight ratio) between the toner and the carrier is preferably as follows:
Carrier = 1: 100 to 30: 100, more preferably 3: 100 to 20: 100.

<Cleaning Blade> The cleaning blade used in the present invention (hereinafter sometimes referred to as a “specific cleaning blade”) is made of an elastic material having a rebound resilience at 10 ° C. of 35% or more. . As the rebound resilience at 10 ° C. of the elastic body,
It is preferably at least 40%.

When a spherical toner is used, it is difficult to maintain the cleaning property under a low temperature condition. As described above, even when the large-diameter external additive is used as the external additive of the toner, it is difficult to stably maintain the cleaning property under a low temperature condition for a long period of time.
The present invention has found that by defining the rebound resilience of a cleaning blade at a low temperature (10 ° C.), the cleaning property under a low temperature condition can be stably maintained for a long period of time. That is, in the present invention, the effect of improving the cleaning property by using the large-diameter external additive as an external additive of the toner is determined by defining the rebound resilience of the cleaning blade at a low temperature and following the unevenness of the surface of the image carrier at a low temperature. And the holding performance (sealing effect) of the large-diameter external additive is improved, thereby realizing even under low temperature conditions.

The rebound resilience of the elastic body constituting the specific cleaning blade is desirably 35% or more in the range of 10 ° C. to 40 ° C. which is the ambient temperature of a normal image forming apparatus. In a general elastic body, the rebound resilience increases as the temperature rises in the above temperature range. If the rebound resilience at 10 ° C. is 35% or more, “35% or more in the range of 10 ° C. to 40 ° C.” Can be satisfied.

The specific method of measuring the rebound resilience is described in JI
SK6255 This is in accordance with the Lupke rebound resilience test of the rebound resilience test method for vulcanized rubber and thermoplastic rubber.
When measuring the rebound resilience, the sample to be measured is preliminarily set at the temperature (in a 10 ° C. environment when the rebound resilience at 10 ° C. is measured) so that the sample to be measured is at the temperature under the measurement conditions at the time of measurement. It is desirable to leave the sample sufficiently.

The cleaning blade is deformed as shown in FIG. 1 by being pressed against the surface of the image carrier. In FIG. 1, reference numeral 2 denotes a cleaning blade, and reference numeral 1 denotes a latent image carrier that rotates in the direction of arrow A. The cleaning blade is held by the holding member 3 to hold the latent image carrier 1.
It is pressed against the surface.

The specific cleaning blade is formed into a shape which can be generally used as a cleaning blade for an image carrier in an electrophotographic apparatus. The overall shape is not particularly limited as long as it is a so-called blade shape in which the edge abuts on the image carrier, but the thickness is generally selected from the range of 1.5 to 2.5 mm, preferably 1. It is selected from the range of 8 to 2.2 mm. The free length of a specific cleaning blade (the length (L ₁ in FIG. ₁ ) between the position where the cleaning blade is fixed in the apparatus and the position of the edge portion that contacts the image carrier) is generally 5 to 5. It is selected from between 15 mm, preferably from 7 to 12 mm. The width may be appropriately set according to the axial length of the image carrier (specifically, the axial length of a portion where the latent image is formed on the image carrier).

The material of the specific cleaning blade is not particularly limited as long as it is an elastic body satisfying the above physical properties, and various elastic bodies can be used. Specific elastic bodies include polyurethane elastic bodies, silicone rubber,
Elastic bodies such as chloroprene rubber are exemplified.

As the polyurethane elastic, generally used is a polyurethane synthesized through an addition reaction between an isocyanate, a polyol and various hydrogen-containing compounds. This is, as a polyol component, a polyether-based polyol such as polypropylene glycol and polytetramethylene glycol, and a polyester-based polyol such as an adipate-based polyol, a polycaprolactam-based polyol, and a polycarbonate-based polyol. 4,4 '
A urethane prepolymer using aromatic polyisocyanates such as diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and toluidine diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, and dicyclohexyl methane diisocyanate; It is prepared by adding a curing agent to the mixture, injecting it into a predetermined mold, crosslinking and curing, and then aging at room temperature. As the curing agent, a dihydric alcohol such as 1,4-butanediol and a trihydric or higher polyhydric alcohol such as trimethylolpropane and pentaerythritol are usually used in combination.

<Image Forming Apparatus and Image Forming Method> Next, the image forming apparatus and the image forming method of the present invention will be described in detail. The image forming apparatus of the present invention includes:
An image carrier, a latent image forming means for forming a latent image on the surface of the image carrier, and a latent image formed on the surface of the image carrier formed with the toner described above to form a toner image A developing unit, a transfer unit that transfers a toner image formed on the surface of the image carrier to a transfer target body, a cleaning unit that includes a specific cleaning blade that removes residual toner on the image carrier surface after the transfer, Is an image forming apparatus provided with:

That is, the image forming apparatus of the present invention is a general electrophotographic image forming apparatus having a cleaning means, wherein the specific cleaning blade is used as the cleaning means, and the above-described large-diameter toner is used as the toner. It is characterized by using a toner containing an external additive.

The linear pressure for pressing the specific cleaning blade against the image carrier is 9.8 × 10 ^{−3 to} 4.9.
× 10 ^-2 N / mm (1.0 to 5.0 gf / mm), more preferably 3.9 × 10 ^{-2 to} 4.9 × 10
A high pressing linear pressure of ^-2 N / mm (4.0 to 5.0 gf / mm) can be used. When the pressing linear pressure of the cleaning blade is 9.8 × 10 ⁻³ N / mm (1.0 gf
/ Mm), cleaning unevenness may occur, and 4.9 × 10 ⁻² N / mm (5.0 gf
/ Mm) is not preferable because the surface of the image carrier may be damaged or the amount of wear may increase.

The bite amount of the specific cleaning blade (deformation amount of the cleaning blade due to being pressed against the surface of the image carrier (d in FIG. 1)) cannot be unconditionally determined, but is 0.8 to 1 It is preferably about 0.6 mm, and more preferably about 1.0 to 1.4 mm. Further, the contact angle of the specific cleaning blade with the image carrier (the angle between the tangent to the image carrier surface and the cleaning blade (θ in FIG. 1))
Although it cannot be said unconditionally, it is preferable to be about 18 to 28 °.

The image forming apparatus of the present invention will be described in detail with reference to the drawings. FIG. 2 is a schematic sectional view showing an electrophotographic apparatus as an example of the image forming apparatus of the present invention. FIG.
Is an electrophotographic photosensitive member (image carrier) 1
0, a charger (charging means) 11 for charging the surface of the electrophotographic photosensitive member 10, a power supply 12 for applying a voltage to the charger 11, and an image for forming a latent image on the surface of the electrophotographic photosensitive member 10 An input device (latent image forming means) 13 and a developing device (developing means) for developing a latent image formed on the surface of the electrophotographic photoreceptor 10 with a toner containing the large-diameter external additive to obtain a toner image
14, a transfer device (transfer unit) 15 for transferring the formed toner image to the surface of the transfer material 20, and a cleaning device (removing the residual toner and the like on the surface of the electrophotographic photoreceptor 10 by a blade 19 as a specific cleaning blade). A cleaning unit 16, a static eliminator 17 for removing the residual potential on the surface of the electrophotographic photoreceptor 10, and a fixing unit 18 for fixing the toner image transferred onto the surface of the transfer-receiving body 20 by heat and / or pressure. Have.

A contact charging type charger 11 such as a charging roller is disposed on the electrophotographic photoreceptor 10 in FIG. 2, and the charger 11 is operated by a voltage supplied from a power supply 12. In the present embodiment, the charger 11 is of a contact charging type. However, in the present invention, the contact charging type and the non-contact charging type are not limited. The cleaning device 16 is provided with a blade 19 serving as the cleaning blade of the present invention at the opening of the box 21. Residual toner and the like removed from the surface of the electrophotographic photosensitive member 10 are stored in the box 21. The structure is

In addition, an image input device (latent image forming means) 1
3, developing unit (developing unit) 14, transfer unit (transfer unit) 1
5. The configurations of the static eliminator 17 and the fixing unit 18 are not particularly limited in the present invention, and any configurations conventionally known in the field of electrophotography can be applied as they are. In the case of using the contact charging type charger 11 as in this example, the static eliminator 17 is not necessarily provided.

The image forming method of the present invention will be described with reference to the electrophotographic apparatus shown in FIG. Electrophotographic photosensitive member (image carrier) 1
After the surface of 0 is uniformly charged by the charger 11,
A latent image is formed by the image input device (latent image forming means) 13 (latent image forming step). The latent image formed on the surface of the electrophotographic photoreceptor 10 is developed with toner contained in a developing device (developing means) 14 to form a toner image (developing step). The toner image formed on the surface of the electrophotographic photoreceptor 10 is transferred to the surface of the transfer-receiving member 20 inserted between the electrophotographic photoreceptor 10 and a transfer unit (transfer unit) 15 facing the electrophotographic photoreceptor 10 (transfer step). ), And is further fixed by heat and / or pressure of the fixing device 18. On the other hand, the residual toner on the surface of the electrophotographic photosensitive member 10 after the transfer is removed by a cleaning device (cleaning means) 16 having a blade 19 (cleaning step). Then, before proceeding to the next image forming cycle, the residual potential on the surface of the electrophotographic photosensitive member 10 is removed by the charge remover 17.

The large-diameter external additive is supplied to the cleaning blade while being held on the surface of the toner particles. However, the supply amount of the large-diameter external additive becomes extremely small depending on the image pattern on the surface of the image carrier. Parts may occur. In order to prevent this, it is desirable to create a toner image that is not transferred to the transfer member on the surface of the image carrier at an arbitrary or predetermined timing (interval) in a non-image forming cycle. By creating a non-transferred toner image on the image carrier, a large-diameter external additive is supplied to the cleaning blade to stabilize the behavior of the tip of the cleaning blade and maintain stable cleaning performance regardless of the image pattern. Can be.

The "non-image forming cycle" refers to a cycle in which the transfer member is not supplied and the toner image formed on the surface of the image carrier can be transported to the cleaning means (cleaning step) as it is. . The toner image formed here may be any pattern such that the external additive is supplied over the entire length of the cleaning blade, and may be any of a solid image, a halftone image, a line image, and the like. . The timing to create a non-transferred toner image is a fixed number of sheets, a cycle,
It may be every time or the like, or may be any timing.

[0067]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. In the description of the toner composition and the carrier,
Unless otherwise specified, all “parts” mean “parts by weight”.

[Measurement Methods of Physical Properties] Each physical property of the toner composition and each rebound resilience of the cleaning blade were measured by the following methods.

<Measurement of Specific Gravity of External Additive> Specific gravity was measured using a Le Chatelier pycnometer in accordance with JIS K0061 5-2-1. The specific operation was performed as follows. (1) About 250 ml of ethyl alcohol is placed in a Le Chatelier pycnometer, and adjusted so that the meniscus is positioned at the scale. (2) The specific gravity bottle is immersed in a constant temperature water bath, and the liquid temperature is 20.0 ± 0.
When the temperature reaches 2 ° C., the position of the meniscus is accurately read on the scale of the pycnometer (reading accuracy is 0.025 ml). (3) About 100 g of a sample is weighed, and its mass is defined as W. (4) Place the weighed sample in a pycnometer to remove bubbles. (5) The specific gravity bottle is immersed in a constant temperature water bath, and the liquid temperature is 20.0 ± 0.
When the temperature reaches 2 ° C., the position of the meniscus is accurately read on the scale of the pycnometer (reading accuracy is 0.025 ml). (6) The specific gravity is calculated by the following equation. D = W / (L ₂ −L ₁ ) Formula A S = D / 0.9982 Formula B

In the above formulas A and B, D is the density of the sample (2
0 ° C) (g / cm ³ ), S is the specific gravity of the sample (20 ° C), W
Weight (g) of the apparent sample, L ₁ is read of the meniscus prior to placing the sample into the pycnometer (20 ℃) (ml), L 2 reads the meniscus after the sample was placed in the pycnometer (20 ° C. )
(Ml), 0.9982 is the density of water at 20 ° C. (g)
/ Cm ³ ).

<Measurement of Primary Particle Diameter and Standard Deviation of External Additive> Laser diffraction / scattering particle size distribution analyzer (HOR)
Using IBA LA-910), the primary particle size of the external additive and its standard deviation were measured.

<Spherical Degree of External Additive> The sphericity of the external additive was calculated according to the following equation (2) using the true spherical degree of Wadell. Sphericity Ψ = S ′ / S Formula (2) In the above formula (2), S ′ represents a surface area of a sphere having the same volume as an actual particle, and is obtained by calculation from a value of an average particle size. Was. S is the actual surface area of the particles, and B is measured using a Shimadzu powder specific surface area measuring device SS-100.
The value of the ET specific surface area was substituted.

<Average Shape Index SF of Toner Particles> The average shape index SF of toner particles is obtained by sampling a toner and introducing it into an image analyzer (Luzex III, manufactured by Nireco Co., Ltd.) to analyze 100 toner particles. Then, the equivalent circle diameter of each toner particle is measured, and the above formula (1) of each toner particle is determined from the absolute maximum length and the projected area.
Is obtained by calculating a shape index SF represented by the following formula, and calculating an arithmetic average thereof.

<Rebound resilience of the cleaning blade> The rebound resilience of the cleaning blade is measured in accordance with JIS K6255 vulcanized rubber and thermoplastic rubber in accordance with the rebound resilience test method. After standing for a period of time, measurement was performed in each atmosphere as it was.

[Preparation of Large Diameter External Additive] (A) Preparation of Spherical Monodisperse Silica A A silica sol obtained by a sol-gel method is subjected to HMDS (hexamethyldisilazane) treatment, dried and pulverized to obtain a specific gravity of 1%. .50, sphericity [psi = 0.85, average particle diameter D ₅₀ = 135 nm (standard deviation = 29nm <D ₅₀ × 0.2
2 = 29.7 nm) to obtain spherical monodispersed silica A.

(B) Preparation of Spherical Monodispersed Silica B The silica sol obtained by the sol-gel method is subjected to HMDS treatment, dried and pulverized to give a specific gravity of 1.60, a degree of spheroidization = 0.90, and an average particle diameter. A spherical monodisperse silica B having a D ₅₀ = 80 nm (standard deviation = 13 nm <D ₅₀ × 0.22 = 17.6 nm) was obtained.

(C) Preparation of Spherical Monodispersed Silica C The silica sol obtained by the sol-gel method is subjected to HMDS treatment, dried and pulverized to give a specific gravity of 1.50, a degree of spheroidization = 0.70, and an average particle diameter. A spherical monodisperse silica C having a D ₅₀ = 100 nm (standard deviation = 40 nm> D ₅₀ × 0.22 = 22 nm) was obtained.

(D) Preparation of Spherical Monodispersed Silica D The silica sol obtained by the sol-gel method was treated with isobutyltrimethoxysilane, dried and pulverized to give a specific gravity of 1.30 and a degree of spheroidization = 0.70, Average particle diameter D ₅₀ =
100 nm (standard deviation = 20 nm <D ₅₀ × 0.22 = 2
2 nm) of spherical monodispersed silica D was obtained.

(E) Preparation of spherical monodisperse silica E Silica sol obtained by the sol-gel method
By performing silane treatment, drying and pulverizing, specific gravity
1.90, degree of sphere Ψ = 0.60, average particle diameter D ₅₀= 2
00 nm (standard deviation = 40 nm <D₅₀× 0.22 = 44
nm) of spherical monodisperse silica E.

(F) Fumed silica Commercially available fumed silica RX50 (manufactured by Nippon Aerosil Co., Ltd.) was prepared. The fumed silica F has a specific gravity of 2.
2. Sphericity Ψ = 0.58, average particle diameter D ₅₀ = 40 nm
(Standard deviation = 20 nm> D ₅₀ × 0.22 = 8.8 nm)
Met.

(G) Silicone Resin Fine Particles Commercially available silicone resin fine particles (manufactured by Dow Corning Toray) were prepared. The silicone resin fine particles G had a specific gravity of 1.32, a degree of spheroidization of Ψ = 0.90, and an average particle diameter of D ₅₀ = 6.
00 nm (standard deviation = 100 nm <D ₅₀ × 0.22 = 1
32 nm).

[Production of Toner Particles] a) Preparation of Resin Dispersion <Preparation of Resin Dispersion (1)> Styrene 370 g n-butyl acrylate 30 g Acrylic acid・ ・ ・ 8g ・ Dodecanethiol ・ ・ ・ ・ ・ ・ 24g ・ Carbon tetrabromide ・ ・ ・ ・ ・ ・ 4g

The above components were mixed and dissolved, and 6 g of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) and an anionic surfactant (Neogen SC: Daiichi Kogyo Seiyaku Co., Ltd.) 10 g of ion-exchanged water 5
Emulsified and dispersed in a solution of 50 g in a flask,
While slowly mixing for 10 minutes, 50 g of ion-exchanged water in which 4 g of ammonium persulfate was dissolved was added thereto. After purging with nitrogen, the contents in the flask were heated in an oil bath until the temperature reached 70 ° C. while stirring, and the emulsion polymerization was continued for 5 hours. As a result, the average particle size was 155.
nm, a glass transition point Tg = 59 ° C., and a resin dispersion liquid (1) in which resin particles having a weight average molecular weight Mw = 12000 were dispersed.

<Preparation of Resin Dispersion (2)> Styrene 280 g n-butyl acrylate 120 g Acrylic acid 8 g

The above components were mixed and dissolved, and 6 g of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) and an anionic surfactant (Neogen SC: Daiichi Kogyo Seiyaku Co., Ltd.) 12 g of deionized water
Emulsified and dispersed in a solution of 50 g in a flask,
While slowly mixing for 10 minutes, 50 g of ion-exchanged water in which 3 g of ammonium persulfate was dissolved was added thereto. After purging with nitrogen, the contents in the flask were heated in an oil bath until the temperature reached 70 ° C. while stirring, and the emulsion polymerization was continued for 5 hours. As a result, the average particle size was 105
nm, a glass transition point Tg = 53 ° C., and a resin dispersion (2) in which resin particles having a weight average molecular weight Mw = 550,000 were dispersed.

B) Preparation of Colorant Dispersion <Preparation of Colorant Dispersion (1)> Carbon Black (Mogul L: manufactured by Cabot)
50 g Nonionic surfactant (Nonypol 400: manufactured by Sanyo Chemical Co., Ltd.) 5 g Ion-exchanged water 200 g The above components are mixed and dissolved, and a homogenizer (ULTRA (Talux T50: manufactured by IKA Co., Ltd.) for 10 minutes to prepare a colorant dispersion liquid (1) in which colorant (carbon black) particles having an average particle diameter of 250 nm are dispersed.

<Preparation of Colorant Dispersion (2)> Cyan Pigment (CI Acid Blue 15: 3)
70 g Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) 5 g Ion-exchanged water 200 g The above components are mixed and dissolved, and a homogenizer ( The mixture was dispersed for 10 minutes using Ultra Turrax T50 (manufactured by IKA) to prepare a colorant dispersion liquid (2) in which particles of a colorant (cyan pigment) having an average particle diameter of 250 nm were dispersed.

<Preparation of Colorant Dispersion (3)> Magenta Pigment (CI Acid Red 122)
70 g Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) 5 g Ion-exchanged water 200 g The above components are mixed and dissolved, and a homogenizer ( The mixture was dispersed for 10 minutes using Ultra Turrax T50 (manufactured by IKA) to prepare a colorant dispersion (3) in which particles of a colorant (magenta pigment) having an average particle diameter of 250 nm were dispersed.

<Preparation of Colorant Dispersion (4)> Yellow Pigment (CI Acid Yellow 180)
100 g Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) 5 g Ion-exchanged water 200 g The above components are mixed and dissolved to form a homogenizer. (Ultra Turrax T50: manufactured by IKA) was dispersed for 10 minutes to prepare a colorant dispersion liquid (4) in which particles of a colorant (yellow pigment) having an average particle diameter of 250 nm were dispersed.

C) Preparation of Release Agent Dispersion Paraffin Wax (HNP0190: manufactured by Nippon Seiro Co., Ltd., melting point 85 ° C.) 50 g Cationic surfactant (Sanisol B50: Kao Corporation) 5g or more in a round stainless steel flask in a homogenizer (Ultra Turrax T50: manufactured by IKA)
Then, the mixture was dispersed for 10 minutes using a pressure-discharge type homogenizer to prepare a release agent dispersion liquid (1) in which release agent particles having an average particle size of 550 nm were dispersed.

D) Preparation of toner particles: Resin dispersion liquid (1): 120 g Resin dispersion liquid (2): 80 g Colorant dispersion liquid (1) to (4)・ ・ ・ ・ ・ 2
00 g-Release dispersion liquid (1)-40 g-Cationic surfactant (Sanisol B50: manufactured by Kao Corporation)-1.5 g

The above components were homogenized in a round stainless steel flask (Ultra Turrax T50: I).
After mixing and dispersing the mixture in a heating oil bath, the mixture was heated to 50 ° C. while stirring the inside of the flask. After holding at 45 ° C. for 20 minutes, it was confirmed by an optical microscope that aggregated particles having an average particle size of about 4.0 μm were formed. Further, 60 g of the resin dispersion (1) was slowly added to the dispersion as a resin-containing fine particle dispersion. Then, set the temperature of the heating oil bath to 50
C. and kept for 30 minutes. Observation with an optical microscope confirmed that resin-adhered particles having an average particle size of about 4.8 μm were formed.

Further, an anionic surfactant (Neogen SC: Daiichi Kogyo Seiyaku Co., Ltd.) is added to the dispersion containing the resin adhered thereto.
After the addition of 3 g, the inside of the stainless steel flask was sealed, heated to 105 ° C. while stirring using a magnetic force seal, and held for 4 hours. After cooling, the reaction product was filtered, sufficiently washed with ion-exchanged water, and dried to obtain toner particles of each color. Details of the obtained toner particles of each color are as follows.

(Toner Particle Black) In the above method, the toner particle black obtained by using the colorant dispersion liquid (1) has an average shape index SF = 118.5 and a volume average particle diameter D ₅₀ = 5.2.
μm. (Toner Particle Cyan) In the above method, the toner particle cyan obtained using the colorant dispersion liquid (2) had an average shape index SF = 119 and a volume average particle diameter D ₅₀ = 5.4 μm. (Toner Particle Magenta) In the above method, the toner particle magenta obtained using the colorant dispersion liquid (3) has an average shape index SF = 120.5 and a volume average particle diameter D ₅₀ = 5.5.
μm. (Toner Particle Yellow) In the above method, the toner particle yellow obtained using the colorant dispersion liquid (4) has an average shape index SF = 120 and a volume average particle diameter D ₅₀ = 5.3 μm.
Met.

[Manufacture of carrier] Ferrite particles (volume average particle size: 50 μm)
100 parts Toluene 14 parts Styrene-methacrylate copolymer (component ratio: 90 /
10) 2 parts carbon black (R330: manufactured by Cabot Corporation)
... 0.2 part A mixture excluding the ferrite particles in the above composition was previously stirred and dispersed using a stirrer for 10 minutes to prepare a coating solution. Next, the obtained coating solution and the ferrite particles were placed in a vacuum degassing kneader, stirred at a temperature of 60 ° C. for 30 minutes, and further degassed while heating under reduced pressure, and dried. Carrier manufactured.

[Cleaning Blades] In this example and the comparative example, three types of cleaning blades A to C whose rebound resilience was measured as shown in FIG. 3 were used.

Example 1 To 100 parts of each of black toner particles, cyan toner particles, magenta toner particles, and yellow toner particles, 3 parts of spherical monodispersed silica A, 10 parts using a Henschel mixer at a peripheral speed of 32 m / s. After blending for 1 minute, 1 part of silica (TS720: manufactured by Cabot Corporation (average particle size d ₅₀ = 12 nm)) was added, and the peripheral speed was 20 m.
/ Sde for 5 minutes, and coarse particles were removed using a sieve of a 45 μm mesh to obtain a toner. Five parts of the obtained toner and 100 parts of the carrier were stirred at 40 rpm for 20 minutes using a V-blender and sieved with a sieve having a mesh of 177 μm to obtain a developer of four colors.

Docucolor 12 manufactured by Fuji Xerox
The charger of No. 50 was changed from a scorotron to a contact-type roll-shaped charger, the normally-installed cleaning blade was removed, and a modified machine having a photoreceptor unit equipped with a cleaning blade A was used instead. 4
The color developer was charged, and the cleaning property was evaluated. This cleaning blade A has a thickness of 2.0 mm,
The free length is 8.0 mm, and the bite amount when the cleaning blade A is brought into contact with the photoconductor (image carrier) is 1.1 m.
m, and the contact angle to the photoreceptor was 22 °. At this time, the linear pressure applied to the photoconductor is 2.6 × 10 ⁻² N / mm (2.7 g).
f / mm).

The cleaning property was evaluated based on streak-like image quality defects on the print and toner contamination of the charging roll. Low temperature and low humidity (10 ° C, 15% RH), medium temperature and moderate humidity (23
° C, 55% RH) and high temperature and high humidity (28 ° C, 85% RH)
A running test of 10,000 sheets was performed in the full-color mode under each of the environmental conditions described above, but no image quality problem occurred under any of the environmental conditions. In addition, no contamination of the charging roll was observed, and the result was good.

Example 2 To 100 parts of each of black toner particles, cyan toner particles, magenta toner particles, and yellow toner particles, 3 parts of spherical monodispersed silica B, 10 parts using a Henschel mixer at a peripheral speed of 32 m / s. After blending for 1 minute, 1 part of silica (TS720: manufactured by Cabot Corporation (average particle size d ₅₀ = 12 nm)) was added, and the peripheral speed was 20 m.
/ S for 5 minutes, and coarse particles were removed using a sieve having a mesh of 45 μm to obtain a toner. Five parts of the obtained toner and 100 parts of the carrier were stirred at 40 rpm for 20 minutes using a V-blender and sieved with a sieve having a mesh of 177 μm to obtain a developer of four colors.

The obtained four color developers were put into the same remodeling machine as in Example 1, and the cleaning property was evaluated under the same conditions as in Example 1. As a result, there was no problem in image quality under any of the environmental conditions, and no contamination of the charging roll was confirmed.

Example 3 To 100 parts of each of black toner particles, cyan toner particles, magenta toner particles, and yellow toner particles, 3 parts of spherical monodispersed silica C, 10 parts using a Henschel mixer at a peripheral speed of 32 m / s. After blending for 1 minute, 1 part of silica (TS720: manufactured by Cabot Corporation (average particle size d ₅₀ = 12 nm)) was added, and the peripheral speed was 20 m.
/ S for 5 minutes, and coarse particles were removed using a sieve having a mesh of 45 μm to obtain a toner. Five parts of the obtained toner and 100 parts of the carrier were stirred at 40 rpm for 20 minutes using a V-blender and sieved with a sieve having a mesh of 177 μm to obtain a developer of four colors.

The obtained four color developers were put into the same remodeling machine as in Example 1, and the cleaning property was evaluated under the same conditions as in Example 1. As a result, there was no problem in image quality under any of the environmental conditions, and no contamination of the charging roll was confirmed.

Example 4 To 100 parts of each of black toner particles, cyan toner particles, magenta toner particles, and yellow toner particles, 3 parts of spherical monodispersed silica D, 10 parts at a peripheral speed of 32 m / s using a Henschel mixer. After blending for 1 minute, 1 part of silica (TS720: manufactured by Cabot Corporation (average particle size d ₅₀ = 12 nm)) was added, and the peripheral speed was 20 m.
/ S for 5 minutes, and coarse particles were removed using a sieve having a mesh of 45 μm to obtain a toner. Five parts of the obtained toner and 100 parts of the carrier were stirred at 40 rpm for 20 minutes using a V-blender and sieved with a sieve having a mesh of 177 μm to obtain a developer of four colors.

The obtained four color developing agents were charged into the same remodeling machine as in Example 1, and the cleaning property was evaluated under the same conditions as in Example 1. As a result, there was no problem in image quality under any of the environmental conditions, and no contamination of the charging roll was confirmed.

Example 5 To 100 parts of each of black toner particles, cyan toner particles, magenta toner particles, and yellow toner particles, 3 parts of spherical monodisperse silica E, and 10 parts at a peripheral speed of 32 m / s using a Henschel mixer. After blending for 1 minute, 1 part of silica (TS720: manufactured by Cabot Corporation (average particle size d ₅₀ = 12 nm)) was added, and the peripheral speed was 20 m.
/ S for 5 minutes, and coarse particles were removed using a sieve having a mesh of 45 μm to obtain a toner. Five parts of the obtained toner and 100 parts of the carrier were stirred at 40 rpm for 20 minutes using a V-blender and sieved with a sieve having a mesh of 177 μm to obtain a developer of four colors.

The obtained four color developers were charged into the same remodeling machine as in Example 1, and the cleaning property was evaluated under the same conditions as in Example 1. As a result, there was no problem in image quality under any of the environmental conditions, and no contamination of the charging roll was confirmed.

Example 6 The cleaning property was evaluated in the same manner as in Example 1 except that the cleaning blade A was replaced with the cleaning blade B. In this case, the linear pressure applied to the photoconductor is 2.
It was 6 × 10 ^-2 N / mm (2.7 g / mm). As a result of evaluation of the cleaning property, no problem in image quality occurred under any of the environmental conditions, and no contamination of the charging roll was confirmed.

Comparative Example 1 One part of silica (TS720: manufactured by Cabot Corporation (average particle diameter d ₅₀ = 12 nm)) was added to 100 parts of each of black toner particles, cyan toner particles, magenta toner particles, and yellow toner particles. In addition, blending was performed at a peripheral speed of 20 m / s for 5 minutes, and coarse particles were removed using a sieve having a mesh of 45 μm to obtain a toner. Five parts of the obtained toner and 100 parts of the carrier were stirred at 40 rpm for 20 minutes using a V-blender and sieved with a sieve having a mesh of 177 μm to obtain a developer of four colors.

The obtained four color developers were charged into the same remodeling machine as in Example 1, and the cleaning property was evaluated under the same conditions as in Example 1. As a result, in a low-temperature and low-humidity environment, 1
Cleaning failure occurred from the first sheet. In addition, the charging roll was very dirty, and the image quality was significantly degraded due to uneven charging. Even in a normal temperature and normal humidity environment and a high temperature and high humidity environment, although not as low as in a low temperature and low humidity environment, cleaning failure occurred in the middle, contamination of the charging roll was recognized, and image quality deterioration due to uneven charging was remarkable.

Comparative Example 2 The cleaning property was evaluated in the same manner as in Example 1 except that the cleaning blade A was replaced with the cleaning blade C. In this case, the linear pressure applied to the photoconductor is 2.
It was 6 × 10 ^-2 N / mm (2.7 gf / mm). As a result of the evaluation of the cleaning property, in a low temperature and low humidity environment, 200
Cleaning failure occurred on one sheet. In addition, the charging roll was very dirty, and the image quality was significantly degraded due to uneven charging. In addition, as the room temperature and the normal humidity and the high temperature and the high humidity become higher, the cleaning failure and the contamination of the charging roll are improved. However, in this example, the environmental stability is poor.

[Comparative Example 3] To 100 parts of each of black toner particles, cyan toner particles, magenta toner particles, and yellow toner particles, 3 parts of fumed silica F, and a peripheral speed of 32 m / s using a Henschel mixer for 10 minutes. After blending, 1 part of silica (TS720: manufactured by Cabot Corporation (average particle size d ₅₀ = 12 nm)) was added, and the peripheral speed was 20 m.
/ S for 5 minutes, and coarse particles were removed using a sieve having a mesh of 45 μm to obtain a toner. Five parts of the obtained toner and 100 parts of the carrier were stirred at 40 rpm for 20 minutes using a V-blender and sieved with a sieve having a mesh of 177 μm to obtain a developer of four colors.

The obtained four color developers were charged into the same remodeling machine as in Example 1, and the cleaning property was evaluated under the same conditions as in Example 1. As a result, in a low-temperature and low-humidity environment, 1
Cleaning failure occurred from the first sheet. In addition, the charging roll was very dirty, and the image quality was significantly degraded due to uneven charging. Even in a normal temperature and normal humidity environment and a high temperature and high humidity environment, although not as low as in a low temperature and low humidity environment, cleaning failure occurred on the way, contamination of the charging roll was observed, and image quality deterioration due to uneven charging was remarkable.

Comparative Example 4 Silicone resin fine particles G were added to 100 parts each of toner particle black, toner particle cyan, toner particle magenta, and toner particle yellow.
After blending for 10 minutes at a peripheral speed of 32 m / s using a Henschel mixer, 1 part of silica (TS720: manufactured by Cabot Corporation (average particle size d ₅₀ = 12 nm)) was added, and a peripheral speed of 20 m / s for 5 minutes. Blending was performed, and coarse particles were removed using a sieve having a mesh of 45 μm to obtain a toner. Five parts of the obtained toner and 100 parts of the carrier were stirred at 40 rpm for 20 minutes using a V-blender and sieved with a sieve having a mesh of 177 μm to obtain a developer of four colors.

The obtained four color developers were charged into the same remodeling machine as in Example 1, and the cleaning property was evaluated under the same conditions as in Example 1. As a result, in a low-temperature and low-humidity environment, 5
Cleaning failure occurred on 00 sheets. In addition, the charging roll was very stained, and image quality was significantly degraded due to uneven charging. In addition, as it becomes normal temperature and normal humidity, high temperature and high humidity,
Although the cleaning failure and the contamination of the charging roll were slightly improved, in this example, even in a high-temperature and high-humidity environment, the cleaning failure and the contamination of the charging roll occurred on the way, and the environmental stability was poor. Understand.

Table 1 below summarizes the results of the above Examples and Comparative Examples. The left column of the results shown in Table 1 below indicates the number of sheets until a cleaning failure occurs, and the right column indicates
This is an evaluation result of the cleaning property obtained from the numerical values in the left column in accordance with the following evaluation criteria. : No problem up to 10,000 sheets △: Cleaning failure occurred from 5000 to 10,000 sheets ×: Cleaning failure occurred from 1,000 to 5,000 sheets XX: Cleaning failure occurred from 1 to 1,000 sheets

[0117]

[Table 1]

[0118]

As described above, according to the present invention,
Even in an image forming apparatus using a spherical toner, it is possible to provide an image forming apparatus and an image forming method at a low cost that ensure good cleaning properties of an image carrier regardless of a use temperature environment without deteriorating image quality. It is.

[Brief description of the drawings]

FIG. 1 is a schematic enlarged sectional view showing a state in which a cleaning blade is pressed against the surface of a latent image carrier.

FIG. 2 is a schematic cross-sectional view illustrating an electrophotographic apparatus as an example of the image forming apparatus of the present invention.

FIG. 3 is a graph showing the relationship between the ambient temperature and the rebound resilience of the cleaning blade used in the example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 latent image carrier 2 cleaning blade 3 holding member 10 electrophotographic photosensitive member (image carrier) 11 charger 12 power supply 13 image input device (latent image forming means) 14 developing device (developing device) 15 transfer device (transfer device) Reference Signs List 16 Cleaning device (cleaning means) 17 Static eliminator 18 Fixing device 19 Blade (cleaning blade) 20 Transfer object 21 Box

Continued on the front page (72) Inventor Hiroe Okuyama 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Taichi Yamada 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Ueno Noriari 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Naoki Ota 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Masahiro Takagi 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Atsuhiko Eguchi 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Inoue Toshishi 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd. (72) Inventor Makoto Sakanobe 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd. (72) Akiya Tomomi Kagita 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Masakazu Takahashi 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Kisho Kojima 2274 Hongo, Ebina-shi Kanagawa Prefecture Address Fuji Xerox Co., Ltd. (72) Inventor Yoshinori Nakano 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. F-term (reference) 2H005 AA08 AA15 CB13 EA05 EA10 2H034 AA06 BF01 BF02 BF03

Claims (2)

[Claims] An image carrier, a latent image forming means for forming a latent image on the surface of the image carrier, and a toner image formed by developing the latent image formed on the surface of the image carrier with toner Developing means, a transfer means for transferring a toner image formed on the surface of the image carrier to a transfer-receiving body, and a cleaning means having a cleaning blade for removing residual toner on the surface of the image carrier after the transfer. An image forming apparatus provided with the toner, wherein the toner has at least an average shape index SF represented by the following formula (1) in the range of 100 to 135, and an external additive having an average particle size of 50 to 500 nm. Wherein the cleaning blade provided in the cleaning means is made of an elastic body having a rebound resilience at 10 ° C. of 35% or more. SF = 100 × πML ² / 4A Formula (1) ML: Absolute maximum length of toner particles A: Projected area of toner particles A latent image forming step of forming a latent image on a surface of the image carrier; a developing step of developing a latent image formed on the surface of the image carrier with toner to form a toner image; An image forming method comprising: a transfer step of transferring a toner image formed on a surface of an image carrier to a transfer-receiving body; and a cleaning step of removing residual toner on the surface of the image carrier after transfer by a cleaning blade. The toner comprises at least toner particles having an average shape index SF of 100 to 135 represented by the following formula (1) and an external additive having an average particle size of 50 to 500 nm; An image forming method, wherein the cleaning blade comprises an elastic body having a rebound resilience at 10 ° C. of 35% or more. SF = 100 × πML ² / 4A Formula (1) ML: Absolute maximum length of toner particles A: Projected area of toner particles