JP2013015734A - Powder conveying apparatus, powder manufacturing method, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder conveying apparatus that suppresses mechanical stress to powder caused by the powder flowing into a gap between an outer peripheral edge portion of a spiral part and an inner peripheral surface of a powder conveying path, a powder manufacturing method using the powder conveying apparatus, an image forming apparatus conveying toner or a carrier using the powder conveying apparatus, and an image forming method.SOLUTION: A screw feeder 500 that is a powder conveying apparatus including an air path (not illustrated) in a screw 1, an air supply device 403 that supplies air to the air path, and an air discharge hole 7 that discharges the air in the air path out to an outer peripheral edge portion 2c.

Description

  The present invention relates to a powder conveying device for conveying powder, a powder manufacturing method using the powder conveying device, and an image forming apparatus and an image forming method for conveying toner and a carrier by the powder conveying device. It is.

A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields.
In electrophotography, an electrostatic latent image is formed on a photoreceptor through a charging and exposure process, the electrostatic latent image is developed into a toner image with a developer containing toner, and a toner image is transferred and fixed. Visualized.
As the developer used here, one using a two-component developer composed of a toner and a carrier is known.

The carrier is manufactured by coating a resin coating layer on a magnetic core material. In the carrier manufacturing process, when the core particles are transported to the coating process or when the carrier particles coated with the resin coating layer are transported, they are transported using a powder transport device. As a powder conveyance device, there is a device that includes a spiral portion and conveys a core material or a carrier that is powder by a rotating conveyance member that rotates to convey the powder in the powder conveyance path in the rotation axis direction. .
Examples of the rotary conveyance member include a screw-shaped conveyance member (hereinafter simply referred to as a screw) in which a spiral portion is fixed to a shaft portion, and a coil-type conveyance member that is not provided with a shaft portion and includes only a spiral portion ( Hereinafter referred to as a coil screw).

  In the powder conveyance device using such a rotary conveyance member, the core material or the carrier may be cracked or the carrier coating layer may be peeled off due to the influence of mechanical stress during conveyance. And if the influence of the mechanical stress at the time of conveyance is large, it will lead to the lifetime reduction of the carrier as a manufactured product, and the wide distribution of charge amount distribution.

Patent Documents 1 to 3 describe a configuration that can reduce mechanical stress on the powder during conveyance with a powder conveyance device using a rotary conveyance member.
For example, Patent Documents 1 and 2 describe a configuration in which a shaft portion of a screw that is a rotary conveying member is provided with a discharge hole that discharges gas from the inside of the screw toward the outside. Further, Patent Document 3 describes a configuration in which a screw hole and a discharge hole that discharges gas from the inside of the screw to the outside are provided on the shaft portion of the screw and both front and rear surfaces in the axial direction.
By discharging the gas from the inside to the outside of the rotary transfer member, the fluidity of the powder to which the transfer force is applied by the screw is improved, and the mechanical stress on the powder is reduced compared to the configuration in which no gas is discharged. Can be achieved.

  However, in the configurations described in Patent Documents 1 to 3, gas is discharged into a spiral groove formed by the axial portion of the screw and both axial front and rear surfaces of the spiral portion. For this reason, the powder in the groove is expelled by the gas, and the powder easily flows into the gap between the outer peripheral edge of the spiral portion and the inner peripheral surface of the powder conveyance path. In the configuration using the screw, stress is easily applied to the powder in the portion where the gap between the outer peripheral edge of the spiral portion and the inner peripheral surface of the powder conveyance path is narrow, so The reduction of mechanical stress is insufficient.

  Such a problem is not limited to the powder transport device used in the carrier manufacturing process, but is also used in the toner manufacturing process and when the developer consisting of the toner and the carrier is measured and transported at the time of shipment. This is a problem that may also occur when conveying powder such as toner. Further, not only the powder used in the image forming apparatus but also other powders are subjected to mechanical stress at the time of conveyance, which may lead to deterioration of the powder and cause some problem.

  The present invention has been made in view of the above problems, and the object thereof is a powder caused by the powder flowing into the gap between the outer peripheral edge of the spiral portion and the inner peripheral surface of the powder conveyance path. Provided are powder conveying device capable of suppressing mechanical stress on the powder, powder manufacturing method using this powder conveying device, image forming apparatus and image forming method for conveying toner and carrier by this powder conveying device It is.

  In order to achieve the above object, the invention of claim 1 includes a powder conveyance path forming member that forms a powder conveyance path through which powder passes, and a spiral portion, and the powder conveyance path is rotated by rotating. In a powder conveying apparatus having a rotary conveying member that applies a conveying force to the powder in the rotation axis direction, a gas passage through which gas passes through the spiral portion, and a gas supply means for supplying gas to the gas passage And a discharge hole for discharging the gas in the gas passage to the outside at the outer peripheral edge portion of the spiral portion.

  In the present invention, since the discharge hole is provided in the outer peripheral edge portion of the spiral portion, the powder pushed by the gas discharged from the discharge hole has the outer peripheral edge portion of the spiral portion and the inner peripheral surface of the powder conveyance path. It is difficult for powder to flow into the gap.

  According to the present invention, it is difficult for powder to flow into the gap between the outer peripheral edge portion of the spiral portion and the inner peripheral surface of the powder conveyance path, where stress is easily applied to the powder. There is an excellent effect that mechanical stress on the powder caused by the powder flowing into the gap between the peripheral edge portion and the inner peripheral surface of the powder conveyance path can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic explanatory drawing of the screw feeder which concerns on this embodiment, (a) is whole explanatory drawing, (b) is an expansion explanatory drawing of a screw. The expansion explanatory drawing of the screw for one volume of the spiral of a screw wing | blade part. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. FIG. 3 is a partially enlarged view showing a part of a tandem part in the printer unit. The perspective explanatory drawing of the coil screw used for the experiment example. Schematic sectional view of the coil screw used in the experimental example, (a) shows an air discharge angle of 20 [°], and (b) shows an air discharge angle of 90 [°].

Hereinafter, an embodiment will be described in a powder conveyance device to which the present invention is applied.
FIG. 1 is a schematic explanatory view of a screw feeder 500 as a powder conveying apparatus according to the present embodiment. 1A is an explanatory view of the entire screw feeder 500, and FIG. 1B is an enlarged explanatory view of the screw 1 provided in the screw feeder 500. FIG.
The screw feeder 500 of the present embodiment has a basic configuration of a screw feeder that conveys powder by rotating a screw that is generally used in a powder manufacturing process.

The screw feeder 500 is composed of a feeder hopper 3 for storing powder, a screw 1 for conveying powder, and a motor 4 for rotating the screw 1. The screw 1 includes a screw shaft portion 1a and a helical screw blade portion 2. As the screw 1 rotates, the screw blade 2 conveys the powder in the feeder hopper 3 to the left in FIG. 1 along the axial direction.
The screw feeder 500 inputs powder from the powder inlet 6 above the feeder hopper 3 and rotates the motor 4 to rotate the screw 1 in order to quantitatively move or quantitatively measure the powder to the next process. This is a device that rotates, conveys the powder in the feeder hopper 3 to the left in FIG. 1, and conveys it toward the powder discharge port 5 via the discharge conveyance pipe 3a.

As shown in FIG.1 (b), let each part of the surface of the screw blade part 2 be the downstream surface part 2a, the upstream surface part 2b, and the outer periphery part 2c. The downstream surface portion 2a is a surface on the downstream side in the powder conveying direction (left direction in FIG. 1) of the screw blade 2, and is a surface that presses the powder toward the downstream side. The upstream surface portion 2b is a surface on the upstream side in the powder conveyance direction of the screw blade 2, and is a surface that contacts the powder but does not press the powder toward the downstream side.
The outer peripheral edge 2c is a surface that forms a thickness portion of the screw blade 2 between the downstream surface 2a and the upstream surface 2b.

  And the screw feeder 500 of this embodiment is equipped with the gas passage not shown in the screw 1, and is equipped with the air discharge hole 7 which discharges the air in a gas passage outside in the outer peripheral part 2c, It is characterized by the above-mentioned. It is a transport device. The screw feeder 500 includes an air supply device 403 that supplies air to the gas passage in the screw 1, and by driving this, an air flow flows through the gas passage, and air is discharged from the air discharge hole 7. It is the structure which assists conveyance of powder by discharge.

Next, the screw 1 of this embodiment will be described in more detail.
FIG. 2 is an enlarged explanatory view of the screw 1 for one turn of the spiral of the screw blade 2. Since the structure of the screw 1 discharges an airflow from the air discharge hole 7 of the outer peripheral edge 2c, the screw blade 2 has a hollow structure and forms a gas passage. The air supply device 403 provided in the vicinity of the motor 4 supplies discharge air to the gas passage in the screw blade 2 and discharges air from the air discharge hole 7. The air discharge hole 7 has at least one, preferably two or more air discharge holes 7 for one screw 1, and it is preferable to discharge air from a plurality of locations.

With such a configuration, the screw feeder 500 can reduce stress on the powder without retaining the powder between the outer peripheral edge 2 c of the screw blade 2 and the hopper bottom surface 8.
Further, it is desirable that the air discharge holes 7 are evenly arranged on the entire circumference of the outer peripheral edge 2c of one screw blade 2. However, when there are too many air discharge holes 7, the discharge pressure discharged from the air discharge holes 7 will fall. For this reason, it is necessary to set the number of air discharge holes 7 of the entire screw blade 2 in balance with the pressure generated by the air supply device 403.

Moreover, when the angle between the air discharge direction 401 which is the direction of the air discharged from the air discharge hole 7 and the powder conveyance direction 9 is an air discharge angle θ, the air discharge angle θ is more than 0 [°]. It is desirable that it be large and less than 90 [°]. Furthermore, since the discharge airflow formed with the air discharged by making it less than 45 degrees desirably flows in the direction which goes to the powder discharge port 5, powder conveyance can be assisted and conveyance capability can be improved.
When the air discharge angle θ is 90 [°] or more, the discharge airflow flows in the opposite direction to the powder discharge port 5, so that the powder transfer cannot be assisted and the transfer capability may be reduced. is there.
The hole diameter of the air discharge hole 7 is preferably equal to or less than the wall thickness of the screw blade part 2, and when the hole diameter of the air discharge hole 7 is greater than the wall thickness, the screw blade part 2 has a chipped shape. It will cause the decrease.

When the screw feeder 500 of the present embodiment is used in a toner manufacturing process, the toner base is quantitatively transported (quantitative supply / mixing to the next process device) or the toner base is mixed with additives (quantity transport ( It can be used for a powder conveying apparatus such as quantitative supply to a next process apparatus (filling into a bottle, etc.) / Measurement).
In addition, when used in the carrier manufacturing process, quantitative transport of uncoated core material (quantitative supply / measurement to the next process device) and quantitative transport of coated carrier (quantitative supply / measurement to the next process device) It can be used for a powder conveying apparatus. Further, it can be used in a powder conveying device for quantitative conveyance (determined supply / metering to a next process apparatus) of a developer in which a carrier and toner are mixed.

<Method for producing resin-coated carrier>
Next, as an example of the above-described carrier manufacturing method, a resin-coated carrier manufacturing method will be described.
[Carrier core particles]
As the carrier core material particles manufactured by the carrier manufacturing method of the present embodiment, those known as two-component carriers for electrophotography, for example, iron, ferrite, magnetite, hematite, cobalt, iron-based, magnetite-based, Mn- Mg-Sr ferrite, Mn ferrite, Mn-Mg ferrite, Li ferrite, Mn-Zn ferrite, Cu-Zn ferrite, Ni-Zn ferrite, Ba ferrite, etc. What is necessary is just to select suitably and to use, and it does not restrict to the said example. The specific gravity is effective for a core material having a relatively high specific gravity of 1.5 to 6.0.

[Binder resin]
The resin forming the carrier coating layer is not particularly limited as long as it is generally used for carriers. For example, silicon resin, fluororesin, acrylic resin, reaction product of acrylic resin and amino resin, epoxy resin, polyurethane resin, fluororesin modified silicone resin, acrylic modified silicone resin, epoxy modified silicone resin, urethane modified silicone resin, etc. However, the present invention is not limited to these. Moreover, coating resin may be used individually by 1 type, may be used by multiple, and may be used in a modified | denatured type.

[Solid particles]
Examples of solid particles include fine powders such as tin oxide, indium oxide doped tin oxide, conductively treated tin oxide, titanium oxide, zinc oxide, iron suboxide, titanium black, and carbon black. It is not limited. Needle-like powders (titanium oxide, zinc oxide, etc.) and flake-like powders (graphite, aluminum flakes, copper flakes, metal flakes such as nickel flakes, conductive mica, etc.) can be used. These can be used alone or in combination. Further, a high resistance material such as hydrophobized silica or alumina powder can be used in combination.

[Coating solution]
The coating liquid is a solution obtained by dissolving or dispersing 0.02 to 90 [parts by weight] of a binder resin in a liquid medium: 100 [parts by weight]. (For example, resin cross-linking agent, resistance adjusting agent, etc.). The ratio of the solid particles to the binder resin is preferably in the range of 5/100 to 600/100. The liquid medium that can dissolve or disperse the binder resin may be a commonly used one. For example, petroleum solvents such as normal hexane and kerosene, halogenated hydrocarbon solvents, benzene, toluene, and xylene. Aromatic solvents such as acetone, methyl ethyl ketone, ketone solvents such as methyl isobutyl ketone, alcohol solvents such as methanol, ethanol and isopropanol, ester solvents such as methyl acetate and ethyl acetate, and diethyl ether Ether solvents, cyclic ethers such as tetrahydrofuran and dioxane, ethylene glycol monomethyl ether (registered trademark = methyl cellosolve), glycol ethers such as ethylene glycol monoethyl ether (registered trademark = ethyl cellosolve), dimethylforma Ruru can be mentioned a nitrogen-containing organic solvents, such as de, but is not limited thereto.

<Toner production method>
The composition of the toner constituting the developer by combining with the toner manufactured by the toner manufacturing method of the present embodiment or the carrier manufactured by the carrier manufacturing method of the present embodiment described above will be described.
The color toner of this embodiment includes not only a color toner generally used for a single color, but also a black toner in addition to yellow, magenta, cyan, red, green, blue and the like used for full color. Further, as the toner, a general toner can be used regardless of whether it is a monochrome toner, a color toner, or a full color toner. For example, conventionally kneaded and pulverized toners and various polymerized toners that have been used in recent years can be used.

  Furthermore, a toner containing a release agent, so-called oilless toner can also be used. In general, oilless toners contain a release agent, so that a so-called spent in which the release agent moves to the carrier surface is likely to occur. However, since the carrier manufactured by the manufacturing method of this embodiment has excellent spent resistance, good quality can be maintained over a long period of time. In particular, oilless full-color toners are generally said to be spent easily because the binder resin is soft, but it can be said that the carrier manufactured by the manufacturing method of this embodiment is very suitable.

  Known binder resins can be used as the binder resin. For example, styrene such as polystyrene, poly-p-styrene, and polyvinyltoluene, and homopolymers thereof, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, Styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-methacrylic acid copolymer Corp., styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-meta Butyl acrylate copolymer, styrene-α-chloromethacrylate methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer Polymer, styrene-isopropyl copolymer, styrene-mer Styrenic copolymers such as inic acid ester copolymers, polythyme methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polyester, polyurethane, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, Modified rosin, terpene resin, phenol resin, aliphatic or aromatic hydrocarbon resin, aromatic petroleum resin and the like can be used alone or in combination.

  Furthermore, as the pressure fixing binder resin, known resins can be mixed and used. For example, polyolefin such as low molecular weight polyethylene and low molecular weight polypropylene, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, styrene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-chlorinated Vinyl copolymer, ethylene-vinyl acetate copolymer, olefin copolymer such as ionomer resin, epoxy resin, polyester resin, styrene-butadiene copolymer, polyvinylpyrrolidone, methyl vinyl ether-maleic anhydride, maleic acid modified phenol resin Phenol-modified terpene resins and the like can be used alone or in combination, but are not limited thereto.

  In addition to the binder resin, colorant, and charge control agent, the toner may contain a fixing aid. Accordingly, it can be used in a fixing system in which toner fixing prevention oil is not applied to the fixing roll, so-called oilless system. Known fixing aids can be used. For example, polyolefins such as polyethylene and polypropylene, fatty acid metal salts, fatty acid esters, paraffin waxes, amide waxes, polyhydric alcohol waxes, silicone varnishes, carnauba waxes and ester waxes can be used, but are not limited thereto.

As the colorant used in the toner such as a color toner, known pigments and dyes capable of obtaining yellow, magenta, cyan, and black toners can be used, and are not limited to those listed here.
Examples of yellow pigments include cadmium yellow, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG and Tartrazine Lake. Can be mentioned.

  Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK.

  Examples of red pigments include Bengala, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B.

  Examples of purple pigments include fast violet B and methyl violet lake. Examples of blue pigments include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and indanthrene blue BC.

  Examples of green pigments include chrome green, chromium oxide, pigment green B, and malachite green lake.

  Examples of black pigments include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides. Moreover, these colorants can use 1 type (s) or 2 or more types.

A toner such as a color toner can contain a charge control agent in the toner as necessary. For example, the color toner can contain a charge control agent in the toner as needed.
For example, nigrosine, an azine dye containing an alkyl group having 2 to 16 carbon atoms (see Japanese Patent Publication No. 42-1627), a basic dye (for example, CI Basic Yellow 2 (C.I. 41000), C.I. I. Basic Yellow 3, C. I. Basic Red 1 (C.I. 45160), C. I. Basic Red 9 (C.I. 42500), C. I. Basic Violet 1 (C.I. 42535), CI Basic Violet 3 (C.I. 42555), C.I.Basic Violet 10 (C.I.45170), C.I.Basic Violet 14 (C.I. 42510), C.I.Basic Violet Blue 1 (C.I.42025), C.I.Basic Blue 3 (C.I.51005), C.I.Basic Blue 5 (C.I. 42140), C.I.Basic Blue 7 (C.I.42595), C.I.Basic Blue 9 (C.I.52015), C.I.Basic Blue 24 (C.I. I.52030), C.I.Basic Blue 25 (C.I.52025), C.I.Basic Blue 26 (C.I.44045), C.I.Basic Green 1 (C.I.42040), C.I. Lake basic pigment lake pigments such as CI Basic Green 4 (CI 42000), CI Solvent Black 8 (CI 26150), benzoylmethyl hexadecyl ammonium chloride, decyl trimethyl chloride, Quaternary ammonium salts such as dialkyls such as dibutyl or dioctyl Compound, dialkyltin borate compound, guanidine derivative, vinyl polymer containing amino group, polyamine resin such as condensation polymer containing amino group, JP-B-41-20153, JP-B 43-27596, JP-B Metal complex salts of monoazo dyes described in JP-A-44-6397 and JP-B-45-26478, salicylic acid and dialkylsalicylic acid described in JP-B-55-42752, JP-B-59-7385 Naphthoic acid, metal complexes of dicarboxylic acid such as Zn, Al, Co, Cr, and Fe, sulfonated copper phthalocyanine pigments, organic boron salts, fluorine-containing quaternary ammonium salts, calixarene compounds, and the like.
Naturally, color toners other than black should avoid the use of charge control agents that impair the target color, and white metal salts of salicylic acid derivatives are preferably used.

  As for the external additive, transferability and durability are further improved by externally adding inorganic fine particles such as silica, titanium oxide, alumina, silicon carbide, silicon nitride, boron nitride and resin fine particles to the base toner particles. This effect can be obtained by covering the wax that lowers transferability and durability with these external additives and reducing the contact area due to the toner surface being covered with fine particles. The surface of these inorganic fine particles is preferably subjected to a hydrophobic treatment, and metal oxide fine particles such as silica and titanium oxide subjected to the hydrophobic treatment are preferably used. As the resin fine particles, polymethyl methacrylate or polystyrene fine particles having an average particle diameter of about 0.05 to 1 [μm] obtained by a soap-free emulsion polymerization method are suitably used.

In addition, the combination of hydrophobized silica and hydrophobized titanium oxide increases the amount of hydrophobized titanium oxide externally added compared to the amount of hydrophobized silica externally charged. The toner can also be excellent in stability. Conventionally used in combination with the above inorganic fine particles, such as silica having a specific surface area of 20 to 50 [m ² / g] or resin fine particles having an average particle diameter of 1/100 to 1/8 of the average particle diameter of the toner. The durability can be improved by externally adding an external additive having a particle size larger than that of the external additive to the toner.
This is because the metal oxide particles externally added to the toner tend to be embedded in the base toner particles in the process where the toner is mixed and stirred with the carrier in the developing device, charged, and used for development. This is because it is possible to prevent the metal oxide fine particles from being embedded by externally adding an external additive having a particle size larger than that of the oxide fine particles to the toner.

  The above-mentioned inorganic fine particles and resin fine particles are contained (internally added) in the toner, but the effect is reduced as compared with the case where the fine particles are added externally, but the effect of improving transferability and durability is obtained and the pulverization property of the toner is improved. Can do. In addition, since external addition and internal addition can be used together to suppress embedding of externally added fine particles, excellent transferability can be stably obtained and durability can be improved.

Typical examples of the hydrophobizing agent used here include the following.
Dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, p-chloroethyltrichlorosilane, Chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, p-chlorophenyltrichlorosilane, 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinylmethoxysilane, vinyl-tris (β-methoxyethoxy) ) Silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinyldichlorosilane, dimethylvinylchlorosilane, octyl Trichlorosilane, decyl-trichlorosilane, nonyl-trichlorosilane, (4-t-propylphenyl) -trichlorosilane, (4-t-butylphenyl) -trichlorosilane, diventyl-dichlorosilane, dihexyl-dichlorosilane, dioctyl-dichlorosilane, dinonyl -Dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4-t-butylphenyl) -octyl-dichlorosilane, dioctyl-dichlorosilane, didecenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dichlorosilane, di- 3,3-dimethylbenthyl-dichlorosilane, trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane Dioctyl-methyl-chlorosilane, octyl-dimethyl-chlorosilane, (4-t-propylphenyl) -diethyl-chlorosilane, octyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetramethyldisilazane, hexaphenyldisilazane , Hexatolyl disilazane and the like.
In addition, titanate coupling agents and aluminum coupling agents can also be used. In addition, as an external additive for the purpose of improving cleaning properties, a lubricant such as a fatty acid metal salt or a fine particle of polyvinylidene fluoride can be used in combination.

A conventionally known method such as a pulverization method or a polymerization method can be applied to manufacture the toner according to the exemplary embodiment.
For example, in the case of the pulverization method, as a device for kneading the toner, a batch type two roll, a Banbury mixer or a continuous type twin screw extruder (for example, KTK type twin screw extruder manufactured by Kobe Steel, TEM manufactured by Toshiba Machine Co., Ltd.) Type twin screw extruder, KCK twin screw extruder, Ikegai Iron Works PCM type twin screw extruder, Kurimoto Iron Works KEX type twin screw extruder, etc.) and continuous single screw kneader (for example, bush) Co. Kneader, etc.) is preferably used.
The melt-kneaded product obtained as described above is cooled and then pulverized. For pulverization, for example, coarsely pulverized using a hammer mill, a funnel plex or the like, and further, a fine pulverizer using a jet stream or mechanical pulverization A machine can be used. The pulverization is desirably performed so that the average particle diameter is 3 to 15 [μm]. Further, the pulverized product is preferably adjusted to a particle size of 5 to 20 [μm] by a wind classifier or the like.

  Subsequently, the external additive is externally added to the base toner. The base toner and the external additive are mixed and stirred using a mixer, and the external additive is crushed and coated on the toner surface. At this time, it is important in terms of durability that external additives such as inorganic fine particles and resin fine particles are uniformly and firmly attached to the base toner. The above is only an example, and the present invention is not limited to this.

Next, an example of an image forming apparatus that can use the developer containing the carrier manufactured in the above-described embodiment will be described.
FIG. 3 is a schematic configuration diagram of a tandem type color copying machine (hereinafter referred to as a copying machine 120) as an image forming apparatus that can use the carrier of the present embodiment. The copying machine 120 includes a copying machine main body (hereinafter referred to as a printer unit 150), a paper feed table (hereinafter referred to as a paper feed unit 200), a scanner (hereinafter referred to as a scanner unit 300) mounted on the printer unit 150, and a scanner unit 300. An automatic document feeder (ADF) (hereinafter referred to as a document feeder 400) attached to the printer. A control unit (not shown) that controls the operation of each device in the copying machine 120 is also provided.

  The scanner unit 300 reads image information of a document placed on the contact glass 32 by the reading sensor 36 and sends the read image information to a control unit (not shown). Based on the image information received from the scanner unit 300, the control unit controls lasers, LEDs, and the like (not shown) arranged in the exposure device 21 of the printer unit 150, and the four drum-shaped photoconductors 10Y, 10C, and 10M. , K is irradiated with laser writing light L. By this irradiation, an electrostatic latent image is formed on the surface of the photoconductors 10Y, 10C, 10M, and 10K, and this latent image is developed into a toner image via a predetermined development process. Note that the suffixes Y, C, M, and K added after the reference numerals indicate specifications for yellow, cyan, magenta, and black.

  In addition to the exposure device 21, the printer unit 150 includes primary transfer rollers 62Y, 62C, 62M, and 62K, a secondary transfer device 22, a fixing device 25, a paper discharge device, a toner supply device (not shown), a toner supply device, and the like. .

  The paper feeding unit 200 includes an automatic paper feeding unit disposed below the printer unit 150 and a manual feeding unit disposed on a side surface of the printer unit 150. The automatic paper feeder separates the two paper cassettes 144 arranged in multiple stages in the paper bank 143, the paper feed roller 142 that feeds out the paper P as a recording medium from the paper cassette, and the paper P that has been fed out. A separation roller 145 and the like are sent to the paper feed unit side paper feed path 146. Further, the printer unit 150 also includes a transport roller 147 that transports the paper P to the main body side paper feed path 148. On the other hand, the manual feed section includes a manual feed tray 51 and a separation roller 52 that separates the paper P on the manual feed tray 51 one by one toward the manual feed path 53.

  A registration roller pair 49 is disposed near the end of the main body side paper feed path 148 of the printer unit 150. The registration roller pair 49 is formed between the intermediate transfer belt 50 as an intermediate transfer body and the secondary transfer device 22 at a predetermined timing after receiving the paper P sent from the paper feed cassette 144 or the manual feed tray 51. To the secondary transfer nip.

  In the copying machine shown in FIG. 3, the operator sets a document on the document table 130 of the document transport unit 400 when copying a color image. Alternatively, after the document conveying unit 400 is opened and a document is set on the contact glass 32 of the scanner unit 300, the document conveying unit 400 is closed and the document is pressed. Then, a start switch (not shown) is pressed. Then, when an original is set on the original conveying unit 400, after the original is conveyed onto the contact glass 32, immediately after the original is set on the contact glass 32, the scanner unit 300 is driven. Start. Then, the first traveling body 33 and the second traveling body 34 travel, and light emitted from the light source of the first traveling body 33 is reflected by the document surface and then travels toward the second traveling body 34. Further, after being reflected by the mirror of the second traveling body 34, it reaches the reading sensor 36 via the imaging lens 35 and is read as image information.

  When the image information is read in this way, the printer unit 150 rotates any one of the three support rollers of the support roller 14, the cleaning counter roller 15, and the secondary transfer counter roller 16 by a drive motor (not shown). The other two support rollers are driven to rotate while being driven. Then, the intermediate transfer belt 50 stretched around these rollers is moved endlessly. Further, laser writing as described above and a development process described later are performed. Then, while rotating the photoreceptors 10Y, 10C, 10M, and 10K, monochrome images of yellow, cyan, magenta, and black are formed on them. These are electrostatically transferred by superimposing them sequentially at the primary transfer nips for Y, C, M, and K where the photoreceptors 10Y, 10C, 10M, and 10K are in contact with the intermediate transfer belt 50, and a four-color superimposed toner image become. Toner images are formed on the photoreceptors 10Y, 10C, 10M, and 10K.

  On the other hand, the paper feed unit 200 operates one of the three paper feed rollers to feed the paper P having a size corresponding to the image information, and feeds the paper P to the main body side of the printer unit 150. Guide to paper path 148. After the paper P that has entered the main body side paper feed path 148 is sandwiched between the registration roller pair 49 and temporarily stopped, the intermediate transfer belt 50 and the secondary transfer roller 22a of the secondary transfer device 22 are aligned with the timing. It is fed into the secondary transfer nip which is a contact portion. Then, in the secondary transfer nip, the four-color superimposed toner image on the intermediate transfer belt 50 and the paper P are brought into close contact in synchronization. Then, the four-color superimposed toner image is secondarily transferred onto the paper P due to the influence of the transfer electric field formed at the nip, the nip pressure, etc., and becomes a full-color image combined with the white color of the paper.

  The paper P that has passed through the secondary transfer nip is fed into the fixing device 25 by the endless movement of the secondary transfer belt 24 of the secondary transfer device 22. The fixing device 25 includes a fixing belt 26 that is rotatably supported by a heating roller including a heat source and a fixing roller, and a pressure roller 27 that forms a fixing nip between the fixing belt and the fixing roller. Is provided. The sheet P fed to the fixing nip of the fixing device 25 is fixed with a full color image by the action of the pressure applied by the pressure roller 27 in the direction of the fixing roller and the heat from the fixing belt 26 heated by the heating roller. Then, the paper is discharged onto a paper discharge tray 57 provided on the side surface of the printer unit 150 via a discharge roller 56.

  As shown in FIG. 3, the printer unit 150 includes a belt unit including an intermediate transfer belt 50, four process units 18Y, 18C, 18M, and 18K that form toner images of respective colors, a secondary transfer device 22, and a belt cleaning device. 17 and a fixing device 25 and the like.

  The belt unit endlessly moves the intermediate transfer belt 50 that is rotatably stretched by a plurality of rollers while being in contact with the photoreceptors 10Y, 10C, 10M, and 10K. In the primary transfer nip for Y, C, M, and K where the photoreceptors 10Y, C, M, and K are brought into contact with the intermediate transfer belt 50, the intermediate transfer belt 50 is backed by the primary transfer rollers 62Y, C, M, and K. It is pressed toward the photoconductors 10Y, 10C, 10M, and 10K from the side. A primary transfer bias is applied to each of the primary transfer rollers 62Y, 62C, 62C, and 62K by a power source (not shown). As a result, a primary transfer electric field for electrostatically moving the toner images on the photoreceptors 10Y, C, M, and K toward the intermediate transfer belt 50 is formed in the primary transfer nips for Y, C, M, and K. Yes. Between each primary transfer roller 62Y, C, M, K, a conductive roller 74 that is in contact with the back surface of the intermediate transfer belt 50 is disposed. In these conductive rollers 74, the primary transfer bias applied to the primary transfer rollers 62 Y, C, M, and K flows into the adjacent process unit 18 through the intermediate resistance base layer 11 on the back side of the intermediate transfer belt 50. It is to prevent this.

  The process units 18Y, 18C, 18M, and 18K support the photoconductors 10Y, 10C, 10M, and several other devices as a single unit on a common support. Can be removed. Taking the process unit 18K for black as an example, this has a developing device 61K as developing means for developing an electrostatic latent image formed on the surface of the photosensitive member 10K into a black toner image in addition to the photosensitive member 10K. ing. Further, it also has a photoconductor cleaning device 63K that cleans transfer residual toner adhering to the surface of the photoconductor 10K after passing through the primary transfer nip. Further, there are a static elimination device (not shown) that neutralizes the surface of the photoreceptor 10K after cleaning, a charging device (not shown) that uniformly charges the surface of the photoreceptor 10K after static elimination, and the like. The process units 18Y, C, and M for other colors have substantially the same configuration except that the color of the toner to be handled is different. The copying machine 120 has a so-called tandem configuration in which these four process units 18Y, 18C, 18M, and 18K are arranged to face the intermediate transfer belt 50 along the endless movement direction.

  FIG. 4 is a partially enlarged view showing a part of a tandem unit 220 including four process units 18Y, 18C, 18M, and 18K. The four process units 18Y, 18C, 18M, and 18K have substantially the same configuration except that the colors of the toners to be used are different, and therefore, Y, C, M, and K attached to the respective reference numerals in FIG. The subscript is omitted. As shown in the drawing, the process unit 18 includes a charging device 59 as a charging unit, a developing device 61, a primary transfer roller 62 as a primary transfer unit, a photoconductor cleaning device 63, and a charge eliminating device 64 around the photoconductor 10. Etc.

  As the photosensitive member 10, a drum-shaped member is used in which a photosensitive organic layer is applied to a base tube made of aluminum or the like to form a photosensitive layer. However, an endless belt may be used. Further, as the charging device 59, a charging device to which a charging roller to which a charging bias is applied is rotated while being in contact with the photosensitive member 10 is used. A scorotron charger or the like that performs a non-contact charging process on the photoreceptor 10 may be used.

  The developing device 61 develops a latent image using a two-component developer containing a magnetic carrier and a nonmagnetic toner. An agitating unit 66 that conveys the two-component developer contained therein and supplies the developer sleeve 65 with stirring, and development that transfers toner of the two-component developer attached to the developing sleeve 65 to the photoreceptor 10. Part 67.

  The stirring unit 66 is provided at a position lower than the developing unit 67, and is provided on two conveying screws 68 arranged in parallel to each other, a partition plate provided between the conveying screws 68, and the bottom surface of the developing case 70. The toner density sensor 71 is provided.

  The developing unit 67 includes a developing sleeve 65 that faces the photoreceptor 10 through the opening of the developing case 70, a magnet roller 72 that is non-rotatably provided inside the developing sleeve 65, a doctor blade 73 that approaches the developing sleeve 65, and the like. ing. The distance at the closest portion between the doctor blade 73 and the developing sleeve 65 is set to about 500 [μm]. The developing sleeve 65 has a non-magnetic rotatable sleeve shape. In addition, the magnet roller 72 that is prevented from being rotated around the developing sleeve 65 has, for example, five magnetic poles N1, S1, N2, S2, and S3 in the rotation direction of the developing sleeve 65 from the position of the doctor blade 73. ing. Each of these magnetic poles applies a magnetic force to the two-component developer on the sleeve at a predetermined position in the rotation direction. As a result, the two-component developer sent from the stirring unit 66 is attracted and carried on the surface of the developing sleeve 65, and a magnetic brush is formed along the magnetic field lines on the sleeve surface.

  The magnetic brush is regulated to an appropriate layer thickness when passing through the position facing the doctor blade 73 as the developing sleeve 65 rotates, and then conveyed to the developing area facing the photoconductor 10. Then, due to the potential difference between the developing bias applied to the developing sleeve 65 and the electrostatic latent image on the photoconductor 10, it is transferred onto the electrostatic latent image and contributes to development. Further, as the developing sleeve 65 rotates, the developing sleeve 65 returns to the developing portion 67 again, and after being separated from the sleeve surface due to the influence of the repulsive magnetic field between the magnetic poles of the magnet roller 72, the developing sleeve 65 is returned to the stirring portion 66. In the stirring unit 66, an appropriate amount of toner is supplied to the two-component developer based on the detection result by the toner density sensor 71. The developing device 61 may employ a one-component developer that does not include a magnetic carrier, instead of the one that uses a two-component developer.

  As the photoconductor cleaning device 63, a system that presses the cleaning blade 75 made of polyurethane rubber against the photoconductor 10 is used, but another system may be used. In order to improve the cleaning property, this example employs a cleaning device having a contact conductive fur brush 76 whose outer peripheral surface is in contact with the photosensitive member 10 so as to be rotatable in the direction of the arrow in the figure. A metal electric field roller 77 for applying a bias to the fur brush 76 is provided so as to be rotatable in the direction of the arrow in the figure, and the tip of the scraper 78 is pressed against the electric field roller 77. The toner removed from the electric field roller 77 by the scraper 78 falls on the collecting screw 79 and is collected.

  The photoconductor cleaning device 63 having such a configuration removes residual toner on the photoconductor 10 with a fur brush 76 that rotates in a counter direction with respect to the photoconductor 10. The toner adhering to the fur brush 76 is removed by the electric field roller 77 to which a bias that rotates in contact with the fur brush 76 in the counter direction is applied. The toner adhering to the electric field roller 77 is cleaned by the scraper 78. The toner recovered by the photoconductor cleaning device 63 is brought to one side of the photoconductor cleaning device 63 by the recovery screw 79 and returned to the developing device 61 by the toner recycling device 80 for reuse.

  The static eliminator 64 includes a static elimination lamp or the like, and removes the surface potential of the photoconductor 10 by irradiating light. The surface of the photoreceptor 10 that has been neutralized in this way is uniformly charged by the charging device 59 and then subjected to an optical writing process.

  A secondary transfer device 22 is provided below the belt unit in the drawing. The secondary transfer device 22 is provided with a secondary transfer roller 23a to which a secondary transfer bias is applied by a power source (not shown). Then, the intermediate transfer belt 50 and the secondary transfer belt 24 are sandwiched between the secondary transfer counter roller 16 and the intermediate transfer belt 50 and the secondary transfer belt 24 move in the same direction at the contact portion while contacting. A secondary transfer nip is formed. A four-color superimposed toner image on the intermediate transfer belt 50 is secondarily transferred to the sheet P fed from the registration roller pair 49 to the secondary transfer nip due to the influence of the secondary transfer electric field and the nip pressure. An image is formed. The sheet P that has passed through the secondary transfer nip is separated from the intermediate transfer belt 50 by the curvature of the intermediate transfer belt 50, and is rotatably stretched by the secondary transfer roller 23a and the secondary transfer belt downstream roller 23b. While being held on the surface of the secondary transfer belt 24, it is conveyed to the fixing device 25 as the secondary transfer belt 24 moves endlessly.

  The surface of the intermediate transfer belt 50 that has passed through the secondary transfer nip approaches a position where the cleaning counter roller 15 supports the surface. Here, the intermediate transfer belt 50 is sandwiched between the belt cleaning device 17 that contacts the front surface (loop outer surface) and the cleaning counter roller 15 that contacts the back surface. Then, after the transfer residual toner adhering to the front surface is removed by the belt cleaning device 17, it sequentially enters the primary transfer nip for Y, C, M, K, and the next four-color toner image. Are superimposed.

In general, the registration roller pair 49 is often used while being grounded, but it is also possible to apply a bias for removing paper dust from the paper P.
A sheet reversing device 28 (see FIG. 3) is provided below the secondary transfer device 22 and the fixing device 25 so as to extend in parallel with the tandem portion 220 described above. As a result, the sheet P that has undergone the image fixing process on one side is switched by the switching claw 55 to the sheet reversing device side, and is reversed and enters the secondary transfer nip again. Then, after the secondary transfer process and the fixing process of the image are performed on the other side, the sheet is discharged onto the discharge tray 57.

<Image forming method>
The image forming method of the present embodiment includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step. Preferably, it includes a cleaning process, and further includes other processes appropriately selected as necessary, for example, a static elimination process, a recycling process, a control process, and the like.

  The copying machine 120 as an image forming apparatus of the present embodiment includes a photosensitive member 10 that is an electrostatic latent image carrier, an exposure device 21 that is an electrostatic latent image forming unit, a developing device 61 that is a developing unit, and a transfer unit. A secondary transfer device 22 that is a fixing unit, and a fixing device 25 that is a fixing unit. The photosensitive member cleaning device 63 is preferably a cleaning unit, and other units are selected as necessary, for example, a neutralization unit 64 as a neutralization unit, a toner recycling device 80 as a recycling unit, As a control means, a control device (not shown) is provided.

  In the copying machine 120 shown in FIGS. 3 and 4, the electrostatic latent image forming step can be performed by the exposure device 21 as electrostatic latent image forming means, and the developing step can be performed by the developing device 61 as developing means. it can. Further, the transfer process can be performed by the secondary transfer device 22 which is a transfer unit, and the fixing process can be performed by the fixing device 25 which is a fixing unit. Further, the cleaning process can be performed by the photoconductor cleaning device 63 which is a cleaning means, and the other processes can be performed by other means.

<Electrostatic latent image forming step and electrostatic latent image forming means>
The electrostatic latent image forming step is a step of forming an electrostatic latent image on an electrostatic latent image carrier such as the photoconductor 10. The material, shape, structure, size, etc. of the electrostatic latent image carrier are not particularly limited and can be appropriately selected from known ones, but the shape is preferably a drum shape. Examples of the material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine. Among these, amorphous silicon or the like is preferable in terms of long life.

The formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then exposing it like an image. Electrostatic latent image forming means such as the exposure device 21 Can be performed.
The electrostatic latent image forming means includes, for example, a charger such as a charging device 59 that uniformly charges the surface of the electrostatic latent image carrier and a surface of the electrostatic latent image carrier such as the photosensitive member 10 in an image-like manner. And at least an exposure device such as an exposure device 21 for exposure.
Charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using a charger.

The charging device such as the charging device 59 is not particularly limited and may be appropriately selected depending on the purpose. For example, the charging device 59 itself having a conductive or semiconductive roll, brush, film, rubber blade, or the like. Examples thereof include a known contact charger, a non-contact charger using corona discharge such as corotron and scorotron.
The exposure can be performed, for example, by exposing the surface of the electrostatic latent image carrier imagewise using an exposure device. The exposure device such as the exposure device 21 is not particularly limited as long as the surface of the electrostatic latent image carrier charged by the charger can be exposed like an image to be formed, and is appropriately selected according to the purpose. be able to. For this reason, for example, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system can be used. In addition, as the exposure device, an optical back side system that performs imagewise exposure from the back side of the electrostatic latent image carrier may be adopted.

<Development process and development means>
The development step is a step of developing the above-described electrostatic latent image with toner to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using toner, and can be performed by a developing unit such as the developing device 61.
The developing means is not particularly limited as long as it can be developed using toner, for example, and can be appropriately selected from known ones. For example, toner is accommodated and electrostatic image development is performed on an electrostatic latent image. A toner having at least a developing device capable of applying the toner for contact in a contact or non-contact manner is preferably used.

The developing device may be a single-color developing device or a multi-color developing device. For example, a stirrer that frictionally stirs toner for developing an electrostatic image and charges it, and a rotatable magnet roller Preferred examples include those having the following.
In the developing device, for example, the toner and the carrier are mixed and stirred, and the toner toner for developing the electrostatic image is charged by the friction at that time, and is held in a raised state on the surface of the rotating magnet roller to form a magnetic brush. Is done. Since the magnet roller is disposed in the vicinity of the electrostatic latent image carrier such as the photoconductor 10, a part of the electrostatic charge image developing toner constituting the magnetic brush formed on the surface of the magnet roller is electrically It moves to the surface of the electrostatic latent image carrier (photoreceptor) by an attractive force. As a result, the electrostatic latent image is developed with toner, and a visible image is formed with toner on the surface of the electrostatic latent image carrier (photoconductor).

  The developer accommodated in the developing device is a developer containing toner, but the developer may be a one-component developer or a two-component developer. The resin coating carrier contained in the developer is a manufactured resin coating carrier manufactured using the screw feeder 500 in the manufacturing process of the present embodiment.

Hereinafter, the prior art will be described.
In electrophotographic image formation, an electrostatic latent image is formed by an electrostatic charge on an image carrier such as a photoconductive material, and charged toner particles are attached to the electrostatic latent image to form a visible image. After the toner image is formed, the toner image is transferred to a recording medium such as paper and fixed to form an output image.
In recent years, copying and printer technologies using an electrophotographic system are rapidly expanding from monochrome to full color, and the full color market tends to expand. Color image formation by full-color electrophotography generally reproduces all colors by laminating three color toners of three primary colors, yellow, magenta, and cyan, or four color toners with black added thereto. .
Therefore, in order to obtain a clear full color image with excellent color reproducibility, it is necessary to smooth the fixed toner image surface to some extent to reduce light scattering.

For these reasons, the image gloss of conventional full-color copying machines or the like is often medium to high gloss of 10 to 50%.
In general, as a method for fixing a dry toner image on a recording medium, a contact heating fixing method in which a roller or belt having a smooth surface is heated and pressed against the toner is frequently used. This method has high thermal efficiency and high-speed fixing, and is advantageous in that it can give gloss and transparency to the color toner. However, the surface of the heat-fixing member is brought into contact with the molten toner under pressure. Since the toner image is peeled off from the surface of the post-heating fixing member, a so-called offset phenomenon occurs in which a part of the toner image adheres to the surface of the heat fixing member and is transferred onto another image.

For the purpose of preventing this offset phenomenon, there is a method in which the surface of the heat fixing member is formed of silicone rubber or fluorine resin having excellent releasability, and further, a release oil such as silicone oil is applied to the surface of the heat fixing member. It was generally adopted. However, this method is extremely effective in preventing toner offset, but a device for supplying release oil is necessary, and the fixing device becomes large and unsuitable for downsizing the machine.
For this reason, in a monochrome toner, by adjusting the molecular weight distribution of the binder resin so that the melted toner does not break internally, the viscoelasticity at the time of melting of the toner is increased, and a release agent such as wax is further included in the toner. There is a tendency to employ a method in which the release oil is not applied to the fixing roller (oilless) or the amount of oil applied is very small.

  On the other hand, as for color toners, there is a tendency toward oil-less for the purpose of downsizing machines and simplifying the configuration as in monochrome. However, as described above, in order to improve the color reproducibility of the color toner, it is necessary to smooth the surface of the fixed image, so the viscoelasticity at the time of melting must be lowered, and the color toner is not glossy It is easier to offset than monochrome toner, and it becomes more difficult to make the fixing device oil-less and to apply a small amount.

In addition, when a release agent is contained in the toner, the adhesion of the toner is increased and the transfer property to the transfer paper is lowered. Further, the release agent in the toner contaminates the frictional charging member such as a carrier to reduce the charging property. This causes a problem that the durability is lowered.
Regarding the carrier, while the demand for faster and more beautiful image formation is increasing, the stress received by the developer containing the carrier and the toner has increased dramatically with the recent increase in machine speed. Even in a carrier having a long life, a sufficient life cannot be obtained, and further improvement in durability is required.
Furthermore, in terms of high image quality, with a reduction in toner diameter and carrier diameter, it is required to narrow the charge amount distribution. When the distribution becomes wide, toner stains (background fogging) in non-image areas. It becomes easy to become a very serious defect image.

In order to deal with such a problem, for example, Patent Document 5 and Patent Document 6 propose an electrophotographic carrier in which particles having a diameter larger than the film thickness are contained in a coating layer. Further, in Patent Document 7, a coating film containing two types of particles, a toner, a first particle having a diameter larger than the film thickness, and a second particle having a diameter smaller than the film thickness is formed on the core material surface. A method has been proposed in which development is performed while replenishing the provided carrier to the developing device and discharging excess developer in the developing device.
In Patent Document 8, a plurality of resin coating layers are provided on a magnetic core, and needle-like or scaly conductive powder is applied to a first coating layer directly above the magnetic core by a bead mill using glass beads. A dispersed carrier for an electrophotographic developer is described.

  However, Patent Document 5 and Patent Document 6 are the particle diameters present in the coating layer, Patent Document 7 is the particle diameter and development method present in the coating layer, and Patent Document 8 is a content relating to the dispersion method of the conductive powder present in the coating layer. Even in the devices described in Patent Documents 5 to 8, the effects are lost due to the cracking of the core material / carrier and peeling of the coating layer due to the influence of mechanical stress during the manufacturing process. As the mechanical stress in the manufacturing process, there is a large stress that is received in a transport device that transports the core material or carrier to the next process.

Examples of means for conveying the core material or carrier generally include conveyance by a screw, conveyance by vibration, conveyance by a rotary valve, and the like.
Among them, as a means for conveying the core material or the carrier, screw conveyance is often employed from the viewpoint of operation maintenance, reliability, and required power.
However, since high productivity is desired from the viewpoint of cost reduction, it will be in the direction of higher rotation or larger size of the screw, but the stress on the core material or carrier will be correspondingly increased, and in the conveyance of the screw feeder This leads to a decrease in carrier life and a broadening of the charge amount distribution due to occurrence of cracks in the core material / carrier and peeling of the coating layer.

As a configuration for solving such a problem, for example, Patent Document 2 describes a powder fluid supply device that suppresses the generation of toner agglomerates having a rotating blade and a jet outlet at an axial center portion between the rotating blades. Has been. Patent Document 3 proposes a structure including a large number of nozzle ports for injecting a pressure fluid (airflow) into a groove part surrounded by a screw conveyor shaft part and blades around the screw conveyor shaft part. Further, as a developer supply device for an image forming apparatus, Patent Document 9 proposes means for forming spiral blades having different numbers of windings. However, in these apparatuses, there are a lot of stresses on the powder due to the presence of a plurality of rotating screws.
Moreover, as a structure which injects an airflow from a screw member, although patent document 1 and patent document 4 are proposed, the reduction to the stress to powder is not enough.

  As a result of repeated studies by the present inventors in order to solve the above-described problems, in a conveying device using a normal screw, stress on the core material or the carrier occurs due to the rotation of the screw rotor blade, and the core material or the carrier is It was found that cracking and peeling of the coating layer occurred, leading to a decrease in carrier life and a broad distribution of charge amount distribution.

The screw feeder 500 as the powder conveying device of the above-described embodiment is a conveying device that combines the ejection of air and a screw blade, which can reduce the speed of screw rotation, that is, reduce stress on the core material or the carrier. Can be effectively solved.
Furthermore, in addition to solving the above-described problems, the powder conveyance device of the present embodiment does not reduce the conveyance amount originally required for the powder conveyance device, and the core material or carrier remains on the bottom of the conveyance device, resulting in loss. This can also improve the production phenomenon and contribute to a reduction in production costs.

The screw feeder 500 of the present embodiment includes a gas passage (not shown) in the screw 1 and an air supply device 403 that supplies air to the gas passage, and the gas passage is formed in the outer peripheral edge portion 2 c of the screw blade portion 2 of the screw 1. An air discharge hole 7 for discharging the air inside is provided.
In such a powder manufacturing method using the screw feeder 500, stress on the powder due to the screw 1 during conveyance is suppressed, and deterioration of the powder (such as cracking of the core material or carrier) due to this stress is suppressed. In addition, it is possible to produce a developer having a long lifetime and a narrow distribution of charge amount.

  The screw feeder 500 sets the air discharge angle θ when the angle between the air discharge direction 401 that is the direction of the air discharged from the air discharge hole 7 and the powder transport direction 9 is the air discharge angle θ. It is set to less than 90 [°]. With such a configuration, stress on the powder due to the screw 1 at the time of conveyance is suppressed, and even in a configuration in which air is discharged, a long life and a narrow distribution of charge amount are achieved without reducing the conveyance capability. Certain developers can be produced.

  Further, the screw feeder 500 has two or more air discharge holes 7 with respect to the outer peripheral edge 2 c of the screw blade 2 of the screw 1. By providing a plurality of air discharge holes 7, it is possible to further reduce cracking of the core material or carrier due to stress from the screw 1, and it is possible to manufacture a core material or carrier that has a long life and a narrow distribution of charge amount. .

Further, in the screw feeder 500, the discharge pressure discharged from the air discharge hole 7 of the airflow is a pressure equal to or higher than the atmospheric pressure in any air discharge hole 7. By satisfying this condition, it is possible to realize a configuration in which airflow is discharged from all the air discharge holes 7.
By using the screw feeder 500 of the present embodiment in the powder conveying step in the carrier manufacturing method, it is possible to reduce the stress applied to the carrier during manufacturing, and to extend the life of the carrier and sharpen the charge distribution. Connected.
Further, by using the screw feeder 500 of the present embodiment in the powder conveying step in the toner manufacturing method, it is possible to reduce the stress applied to the toner at the time of manufacturing, and to deteriorate the toner such as the removal of the external additive. It can prevent and improve durability.
To improve the quality of the image to be formed by using a developer including a carrier having a long life and a sharp charge distribution and a toner having improved durability during manufacture in an image forming apparatus such as the copying machine 120. Can do.

  In the case of particles having a relatively heavy specific gravity of 1.5 to 6.0 as the specific gravity of the carrier, the particles are difficult to move and the stress applied to the particles is likely to increase. By using the screw feeder 500 of the present embodiment in the powder conveying step in the manufacturing method for manufacturing such a carrier, stress can be reduced, and a carrier having a long life and a sharp charge distribution can be obtained. Can be obtained.

<Experimental example>
Hereinafter, specific examples and comparative examples of carriers manufactured by a carrier manufacturing method using a powder conveying apparatus to which the present invention is applied will be described as experimental examples, but the present invention is not limited to these. . In the following, parts are parts by weight.

[Example 1]
Acrylic resin solution (solid content: 50 [mass%]): 80 [parts by mass]
Guanamine solution (solid content: 70 [mass%]): 25 [parts by mass]
Acidic catalyst (solid content: 40 [mass%]): 1 [part by mass]
Silicone resin solution (solid content: 20 [mass%]): 250 [parts by mass]
Aminosilane (solid content: 100 [mass%]): 2 [parts by mass]
Conductive-treated titanium oxide particles (surface: ITO treatment, primary particle size: 70 nm, volume resistivity: 1.0 × 10 ² [Ω · cm]): 170 [parts by mass]
-Toluene: 800 [parts by mass]
The above materials are put into a circulation tank, and dispersion processing is performed by a bead mill disperser [Nano Getter (DMR-L110 type) [manufactured by Ashizawa Finetech Co., Ltd., having a bead classification mechanism in the dispersion chamber] to form a coating film A solution was obtained.

  Next, fired ferrite powder [DFC-400M (Mn ferrite, manufactured by DOWA IP Creation Co., Ltd.), specific gravity: 2.4] having an average particle diameter of 35 [μm] as core material particles is used as the screw feeder 500 of this embodiment. Weigh it and put it into a Spira coater (Okada Seiko Co., Ltd.). Thereafter, the coating film forming solution was applied to the surface of the core particle so as to have a film thickness of 0.2 [μm] at a coater internal temperature of 40 [° C.] and dried. The obtained carrier was baked in an electric furnace at 150 [° C.] for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 63 [μm], and [Carrier 1] (charge amount: 32.1 [−μc / g], volume resistivity: 11.7 [Log (Ω Cm)]) was obtained.

As the rotary conveying member of the screw feeder 500 of the present embodiment, the screw 1 provided with the wing portion and the shaft portion is used in the configuration shown in FIGS. 1 and 2, but in this experimental example, the coil screw shown in FIG. 101 was used.
Moreover, the schematic sectional drawing of the coil screw 101 used in this experiment example is shown in FIG. FIG. 6A is an explanatory diagram of a configuration with an air discharge angle of 20 [°], and FIG. 6B is an explanatory diagram of a configuration with an air discharge angle of 90 [°].

The specifications and conditions of the screw feeder 500 used in the core material conveying device are as follows.
・ Screw: Coil screw (8 rolls)
-Ejection hole: One place in 4 rolls-Ejection air pressure: 0.5 [Mpa]
・ Blowing air angle: 20 [°]

Next, the composition of the toner mixed with the carrier described above is shown below.
・ Binder resin (polyester resin): 100 [parts by mass]
-Mold release agent: (carnauba wax): 7 [parts by mass]
Charge control agent (E-84 [manufactured by Orient Chemical Industries]): 1 [parts by mass]
Colorant (CIPY180): 6 [parts by mass]
Among the above materials, the colorant, the binder resin, and pure water were mixed at a ratio of 1: 1: 0.5 and kneaded by two rolls. Kneading was performed at 70 [° C.], and then the roll temperature was raised to 120 [° C.] to evaporate water and prepare a master batch in advance. Using the master batch thus obtained, the materials were weighed so as to be the same as the above recipe, mixed with a Henschel mixer, melt-kneaded for 40 minutes at 120 [° C.] with two rolls, cooled, and then hammered with a hammer mill After coarse pulverization, fine powder obtained by fine pulverization with an air jet pulverizer was classified to prepare toner base particles having a weight average particle diameter of 5 [μm].
Further, to 100 parts of the toner base material, 1 part of silica whose surface was hydrophobized and 1 part of titanium oxide whose surface was hydrophobized were added and mixed with a Henschel mixer to obtain yellow toner [Toner 1 ] Was obtained.
[Toner 1] thus obtained: 7 [parts] and [Carrier 1]: 93 [parts] weighed using the screw feeder 500 of the present embodiment were mixed and stirred to obtain a toner concentration of 7 [wt%]. A developer was prepared.

[Example 2]
In Example 1, except for the specifications and conditions of the core material conveying device, the carrier was formed in the same manner, and [Carrier 2] (charge amount: 35.5 [-μc / g], volume resistivity: 13.2 [Log (Ω Cm)]) was obtained.
The specifications and conditions of the screw feeder 500 used in the core material conveying device are as follows.
・ Screw: Coil screw (8 rolls)
-Ejection hole: One place in 4 rolls-Ejection air pressure: 0.3 [Mpa]
・ Blowing air angle: 20 [°]
A developer was produced from [Carrier 2] and [Toner 1] obtained in this manner by the same method as in Example 1 except for the carrier conveying device specifications and conditions.

Example 3
In Example 2, except for the specifications and conditions of the core material conveying device, the carrier was formed in the same manner, and [Carrier 3] (charge amount: 37.1 [-μc / g], volume specific resistance: 13.7 [Log (Ω Cm)]) was obtained.
The specifications and conditions of the screw feeder 500 used in the core material conveying device are as follows.
・ Screw: Coil screw (8 rolls)
・ Blowout holes: 1 each for 2, 4, 6 and 8 rolls (total of 4)
・ Blowing air pressure: 0.3 [Mpa]
・ Blowing air angle: 20 [°]
A developer was produced from [Carrier 3] and [Toner 1] obtained in this manner by the same method as in Example 1 except for the carrier conveying device specifications and conditions.

[Comparative Example 1]
In Example 3, except for the specifications and conditions of the core material conveying device, the carrier was formed in the same manner, and [Carrier 4] (charge amount: 38.3 [-μc / g], volume specific resistance: 14.1 [Log (Ω Cm)]) was obtained.
The specifications and conditions of the screw feeder 500 used in the core material conveying device are as follows.
・ Screw: Coil screw (8 rolls)
-Ejection hole: None-Developers were produced in the same manner as in Example 1 except for the carrier carrier device specifications and conditions obtained for [Carrier 4] and [Toner 1].

Example 4
In Example 1, a carrier was formed in the same manner except that a material having a core core specific gravity of 1.2 was used, and [Carrier 5] (charge amount: 35.7 [-μc / g], volume resistivity: 13. 1 [Log (Ω · cm)]).
A developer was produced from [Carrier 5] and [Toner 1] thus obtained in the same manner as in Example 1.

Example 5
In Example 1, except for the specification and conditions of the core material conveying device, the carrier was formed in the same manner, and [Carrier 6] (charge amount: 33.8 [-μc / g], volume resistivity: 12.5 [Log (Ω Cm)]) was obtained.
The specifications and conditions of the screw feeder 500 used in the core material conveying device are as follows.
・ Screw: Coil screw (8 rolls)
-Ejection hole: One place in 4 rolls-Ejection air pressure: 0.5 [Mpa]
・ Blowing air angle: 90 [°]
A developer was produced from [Carrier 6] and [Toner 1] thus obtained by the same method as in Example 1 except for the carrier conveying device specifications and conditions.

  The conveyance devices of Examples 1 to 3 have higher conveyance capability than the first comparative example, and the remaining amount after discharge is small. Using the developers prepared by the manufacturing method including the conveyance devices of Examples 1 to 5 and Comparative Example 1, evaluation of background fogging and aging solid carrier adhesion was performed.

Table 1 shows the use of the conveying devices of the examples and comparative examples.

  The discharge air pressure in Table 1 was obtained by pressure analysis using a simulation analysis program from the pressure of the air supply device 403 and dimensions such as the diameter of the discharge port. In this pressure analysis, the atmospheric pressure was analyzed as 0.1 [Mpa].

Table 2 shows the evaluation results of each experimental example and comparative example.

In addition, the measurement method and evaluation method regarding the said evaluation item followed the following.
[Remaining discharge evaluation method]
After dropping into a carrier transport device of 100 [kg] and discharging the carrier with a predetermined cut-out amount, the rotation of the rotor blades is stopped when the carrier stops being discharged from the transport device discharge port, and the remaining carrier in the transport device The weight was measured.
[Charging amount measurement method]
The charge amount was 93 [wt%] for the carrier, and the toner was mixed at a ratio of 7 [wt%] and frictionally charged, and a blow-off device TB-200 (manufactured by Toshiba Chemical Co., Ltd.) was used. It was measured.
[Skin cover evaluation method]
Developer is set in a commercially available digital full color printer (Imagio MP C5000, manufactured by Ricoh Co., Ltd.), 1 A4 image with an image area of 5% is output per 1000 sheets per JOB, and then the image area is 0%. A3 image is output, and the toner fog state of the background portion is observed, and it is determined that the toner fog is completely absent, 殆 ど is hardly understood, ◯ is slightly seen, △ is clearly seen, and x is clearly seen. , Δ was accepted and x was rejected.

[Evaluation method for adhesion of solid carrier over time]
The developer was set on a commercially available digital full-color printer (Imagio MP C5000, manufactured by Ricoh Co., Ltd.), and a running evaluation of 300,000 sheets in a single color was performed. Then, the solid carrier adhesion of the developer after the running was evaluated.
The solid image carrier adhesion evaluation method was evaluated by fixing the background potential to 150 [V] using the above-mentioned copying machine, developing the entire solid image on A3 size paper, and observing with a loupe. ◎ when the number of white spots on the image and the total number of carriers actually attached are 0, ◯ when 1-5, △, 11 when 6-10 The case of more than one was determined as x, ×, ○, △ were accepted, and x was rejected.

  From the evaluation results shown in Table 2, the developer prepared by using this apparatus according to Examples 1 to 5 has no lowering of the charge amount due to the core material or carrier cracking and peeling of the coating layer as compared with the comparative example, and the background. It is clear that fogging and adhesion of solid carrier over time are suppressed.

In the above-described embodiments, the screw feeder 500 as the powder conveying device according to the present invention, the powder manufacturing method using the screw feeder 500 in the conveying step, and the carrier manufactured by the powder manufacturing method are described. did.
The configuration to which the powder conveyance device according to the present invention can be applied is not limited to the screw feeder 500. For example, the powder conveying apparatus according to the present invention can be applied as a conveying apparatus that conveys toner as powder in the toner recycling apparatus 80 of the copying machine 120 described above. The powder conveying device according to the present invention can also be applied as a conveying device that conveys toner from a toner bottle of a toner replenishing device that supplies developer into the developing device 61 from a toner bottle (not shown) to the developing device 61. . Further, the present invention can also be applied to a conveying screw 68 that circulates toner and carrier in the developing device 61. Thus, by using the powder conveying device according to the present invention for conveying the developer or the powder constituting the developer in the image forming apparatus, the long life of the developer, which is a powder used for image formation, is used. The quality of the created image can be improved.

  Furthermore, the powder conveying device according to the present invention is not limited to powders related to image formation such as toner and carrier, and any powder conveying device that conveys any powder may cause stress on the powder to be conveyed. Can be reduced.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
[Aspect A]
A powder conveyance path including a powder conveyance path forming member such as a feeder hopper 3 and a discharge conveyance pipe 3a that forms a powder conveyance path through which the powder passes, and a helical portion such as a screw blade 2 are rotated. In a powder conveyance device such as a screw feeder 500 having a rotary conveyance member such as a screw 1 that applies a conveyance force to the powder in the rotation axis direction, a gas such as air is introduced into a spiral portion such as a screw blade 2. A gas passage that passes through and a gas supply means such as an air supply device 403 that supplies gas to the gas passage, and the gas in the gas passage on the outer peripheral edge of the spiral portion such as the outer peripheral edge 2c of the screw blade 2 A discharge hole such as an air discharge hole 7 is provided. According to this, as described in the above embodiment, the outer peripheral edge 2c of the screw blade 2 and the powder are not retained between the outer peripheral edge 2c of the screw blade 2 and the hopper bottom surface 8. It is possible to suppress stress on the powder due to the powder flowing into the gap with the hopper bottom surface 8 which is the inner peripheral surface of the body conveyance path. Thereby, the stress to the powder to convey can be reduced rather than before.
[Aspect B]
In [Aspect A], the angle between the conveyance direction of the rotary conveyance member such as the screw 1 and the discharge direction of the gas from the discharge hole such as the air discharge hole 7 is less than 90 [°]. According to this, as described in the above embodiment, the airflow flows in the gas passage and the air is discharged from the air discharge hole 7, and the conveyance of the powder can be assisted by the discharge of the air.
[Aspect C]
In [Aspect A] or [Aspect B], the spiral portion such as the screw blade 2 is provided with two or more discharge holes such as the air discharge holes 7. According to this, as explained about the above-mentioned embodiment, by discharging air from a plurality of locations, it is possible to blow an air current against the powder at different positions in the transport direction, and the outer peripheral edge of the screw blade 2 It is possible to further suppress the retention of the powder between 2c and the hopper bottom surface 8.
[Aspect D]
In any one of the [Aspect A] to [Aspect C], the pressure in the gas passage at the position of the discharge hole such as the air discharge hole 7 is equal to or higher than the atmospheric pressure. According to this, as described in the above embodiment, it is possible to realize a configuration for discharging air from each air discharge hole 7.
[Aspect E]
In any one of the [Aspect A] to [Aspect D], the rotary conveying member is a coil screw. According to this, as described in the above embodiment,
[Aspect F]
In a powder manufacturing method such as a carrier manufacturing method including at least a transporting step by a powder transporting unit, the powder transporting device according to any one of [Aspect A] to [Aspect E] is used as a powder transporting unit. . According to this, as described in the above embodiment, when the powder to be manufactured is a carrier, the stress applied to the carrier during manufacturing can be reduced, and the life of the carrier can be extended and the charge amount distribution can be sharpened. It leads to.
[Aspect G]
An image of a copying machine 120 or the like provided with a toner image forming unit such as a printer unit 150 that forms a toner image using toner, and a powder conveying unit that conveys toner or / and a carrier used for image formation. In the forming apparatus, the powder conveyance device according to any one of [Aspect A] to [Aspect E] is used as the powder conveyance device. According to this, as described in the above embodiment, the life of the developer to be used can be extended and the quality of the created image can be improved.
[Aspect H]
In an image forming method including a toner image forming step of forming a toner image using toner, and a powder transporting step of transporting toner, which is powder used for image formation, and / or a carrier, the powder transporting step includes: [Aspect A] to [Embodiment E] The powder conveyance device according to any one of the aspects is used. According to this, as described in the above embodiment, the life of the developer to be used can be extended and the quality of the created image can be improved.

DESCRIPTION OF SYMBOLS 1 Screw 1a Screw shaft part 2 Screw blade | wing part 2a Downstream side surface part 2b Upstream side surface part 2c Outer peripheral edge part 3 Feeder hopper 3a Discharge conveyance pipe 4 Motor 5 Powder discharge port 6 Powder input port 7 Air discharge hole 8 Bottom of hopper 9 Powder conveying direction 10 Photoconductor 18 Process unit 21 Exposure device 22 Secondary transfer device 25 Fixing device 50 Intermediate transfer belt 57 Paper discharge tray 61 Developing device 80 Toner recycling device 101 Coil screw 120 Copier 150 Printer unit 401 Air discharge direction 403 Air supply device 500 Screw feeder θ Air discharge angle

Japanese Utility Model Publication No. 62-89228 JP 2001-139153 A Japanese Patent Laid-Open No. 06-183540 Japanese Utility Model Publication No. 58-066461 JP 2007-102159 A JP 2008-70837 A JP 2007-286078 A JP-A-11-184167 Japanese Patent No. 3434085

Claims (8)

A powder conveyance path forming member that forms a powder conveyance path through which the powder passes;
In a powder conveying apparatus comprising a helical conveying part and having a rotating conveying member that applies a conveying force in the direction of the rotation axis to the powder in the powder conveying path by rotating,
A gas passage through which gas passes in the spiral portion, and a gas supply means for supplying gas to the gas passage,
A powder conveying apparatus comprising a discharge hole for discharging the gas in the gas passage to the outside at an outer peripheral edge of the spiral portion. In the powder conveying apparatus according to claim 1,
An angle between a transport direction of the rotary transport member and a gas discharge direction from the discharge hole is less than 90 [°]. In the powder conveying apparatus according to claim 1 or 2,
A powder conveying apparatus comprising two or more discharge holes in the spiral portion. In the powder conveying apparatus according to any one of claims 1 to 3,
The powder conveying apparatus according to claim 1, wherein the inside of the gas passage at the position of the discharge hole is at a pressure equal to or higher than atmospheric pressure. In the powder conveying apparatus according to any one of claims 1 to 4,
The powder conveying apparatus, wherein the rotary conveying member is a coil screw. In a powder production method comprising at least a conveying step by powder conveying means,
6. A method for producing a tree powder comprising using the powder conveying device according to claim 1 as the powder conveying means. Toner image forming means for forming a toner image using toner;
In an image forming apparatus provided with toner, which is powder used for image formation, and / or powder conveying means for conveying a carrier,
An image forming apparatus using the powder conveying apparatus according to claim 1 as the powder conveying apparatus. A toner image forming step of forming a toner image using toner;
In an image forming method including a toner used as image forming powder and / or a powder carrying process for carrying a carrier,
An image forming method using the powder conveyance device according to any one of claims 1 to 5 in the powder conveyance step.

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