JP2004233973A - Image forming method and toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method capable of suppressing deterioration of toner due to rubbing and capable of maintaining high image quality over a prolonged period of time, even when adopted in a high process speed apparatus which attains miniaturization and speeding up. <P>SOLUTION: In the image forming method, when the diameter of a toner carrier is represented by Rd (mm) and the diameter of a toner supply member by Rs (mm), Rs-Rd is equal to 1-10, and a nonmagnetic monocomponent toner is used which comprises toner particles comprising at least a binder resin, a colorant and a release agent and an external additive, and has a degree of agglomeration of 5-30% and an electrical resistivity of 1×10<SP>14</SP>-1×10<SP>18</SP>Ωcm in an electric field of 1×10<SP>4</SP>V/cm. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an image forming method using an electrophotographic technique.

  In recent years, with the spread of copying machines and printers using electrophotography, further speed-up, downsizing, full colorization, and high image quality are required. In addition, with the spread of users, lower cost and free maintenance of copiers and printers are required. Therefore, it is necessary to reduce the number of parts in the machine body and simplify the machine configuration.

  As a result, technical demands on consumer members such as toners and drums are increasing year by year. As a development method, a contact development method using a non-magnetic one-component developer has attracted attention.

  The toner particles of the non-magnetic one-component developer have excellent low-temperature fixability as compared with the magnetic toner. Further, since it does not contain an opaque magnetic material, it is preferable to obtain a full-color or multi-color image, and is a developer that can be used for a light-transmitting medium such as OHP. In addition, since the configuration of the consumed developer is simple, the size of the machine can be reduced and maintenance-free can be achieved.

  As described above, a non-magnetic one-component contact developing method is a very preferable developing method in order to achieve various requirements such as downsizing of a machine, free maintenance, high definition of an image, and full color.

  In order to meet the demand for miniaturization of electrophotographic image forming apparatuses such as copiers, printers, and facsimile machines, the diameter of a toner carrier and a toner supply member that supplies toner to the toner carrier tend to be reduced. . Further, there is a high demand for further high speed, and in order to achieve miniaturization and high speed, an extremely high process speed is required, and the toner carrier and the toner supply member are required to rotate at high speed. At this time, the deterioration of the toner is promoted by the rubbing between the toner supply member and the toner carrier and the rubbing between the toner carrier and the toner regulating member. As the toner deteriorates, the developability decreases and the quality of the formed image deteriorates.

  On the other hand, the electric resistivity of the non-magnetic one-component developer is regulated to improve the durability of charging and the environmental stability (see, for example, Patent Document 1). There has been proposed a technique for suppressing a decrease in image quality (for example, see Patent Document 2).

  Further, in order to suppress the deterioration of the toner supply roller, a technique of making the diameter of the toner supply roller larger than the diameter of the developing roller has been proposed (for example, see Patent Document 3). There has also been proposed a device in which the diameter of the roller is increased (for example, see Patent Document 4).

However, with respect to an image forming method capable of maintaining high image quality by more effectively suppressing toner deterioration due to rubbing, further improvement has been required.
Japanese Patent Publication No. 7-43546 Japanese Patent No. 3272056 JP-A-5-257376 JP-A-6-289705

  The present invention has been made in view of the above problems, and can reduce the deterioration of toner due to rubbing even when used in an apparatus with a high process speed in which miniaturization and high speed are achieved. It is another object of the present invention to provide an image forming method capable of maintaining high image quality for a long time.

The present invention provides a charging step of charging the surface of the latent image carrier, a latent image forming step of forming an electrostatic latent image on the surface of the charged latent image carrier, and a step of developing the electrostatic latent image by a developing unit. A developing step of forming a toner image by visualizing with a magnetic one-component toner, a transferring step of transferring the toner image onto a transfer material with or without an intermediate transfer member, and fixing the toner image on the transfer material An image forming method including a fixing step,
The developing means includes: a toner container containing a non-magnetic one-component toner; a rotatable cylindrical member provided in contact with the latent image carrier and carrying the non-magnetic one-component toner and transporting the non-magnetic one-component toner to the latent image carrier A rotatable cylindrical member having a rotation axis parallel to the rotation axis of the toner carrier, the toner carrier being provided in contact with the toner carrier on the upstream side in the rotation direction from the contact position with the latent image carrier; A toner supply member composed of an elastic body and supplying the non-magnetic one-component toner contained in the toner container to the toner carrier; and a non-magnetic one-component toner in contact with the toner carrier, and A toner regulating member that regulates the amount of the non-magnetic one-component toner.
When the diameter of the toner carrier is Rd (mm) and the diameter of the toner supply member is Rs (mm), the following relational expression (1) is satisfied;
1 ≦ Rs−Rd ≦ 10 (1)
The non-magnetic one-component toner has toner particles containing at least a binder resin, a colorant, and a release agent, and an external additive.
The amount of the external additive to be added is 0.5 to 5.0 parts by mass based on 100 parts by mass of the toner particles;
The external additive includes fine silica powder treated with silicone oil,
The non-magnetic one-component toner has an agglomeration degree of 5 to 30% and an electric resistivity of 1 × 10 ¹⁴ to 1 × 10 ¹⁸ Ωcm in an electric field of 1 × 10 ⁴ V / cm. It relates to a forming method.

Further, the present invention provides a charging step of charging the surface of the latent image carrier, a latent image forming step of forming an electrostatic latent image on the surface of the charged latent image carrier, and a developing unit for developing the electrostatic latent image. A developing step of forming a toner image by visualizing with a non-magnetic one-component toner, a transferring step of transferring the toner image onto a transfer material with or without an intermediate transfer member, and a toner image on the transfer material. And a fixing step of fixing the toner used in the image forming method,
The developing means includes: a toner container containing a non-magnetic one-component toner; a rotatable cylindrical member provided in contact with the latent image carrier and carrying the non-magnetic one-component toner and transporting the non-magnetic one-component toner to the latent image carrier; A toner carrier; provided on the surface of the toner carrier in contact with the toner carrier on the upstream side in the rotational direction from the contact position between the toner carrier and the latent image carrier, and having a rotation axis parallel to the rotation axis of the toner carrier. A toner supply member composed of a rotatable cylindrical elastic body and supplying the non-magnetic one-component toner contained in the toner container to the toner carrier; and abutting on the toner carrier via the non-magnetic one-component toner A toner regulating member for regulating the amount of non-magnetic one-component toner on the toner carrier;
When the diameter of the toner carrier is Rd (mm) and the diameter of the toner supply member is Rs (mm), the following relational expression (1) is satisfied;
1 ≦ Rs−Rd ≦ 10 (1)
The non-magnetic one-component toner has toner particles and an external additive containing at least a binder resin, a colorant, and a release agent,
The amount of the external additive to be added is 0.5 to 5.0 parts by mass based on 100 parts by mass of the toner particles;
The external additive includes fine silica powder treated with silicone oil,
The non-magnetic one-component toner has a cohesion of 5 to 30% and an electric resistivity of 1 × 10 ¹⁴ to 1 × 10 ¹⁸ Ωcm in an electric field of 1 × 10 ⁴ V / cm. About.

  Even when the image forming method of the present invention is used in an apparatus having a high process speed in which miniaturization and high speed have been achieved, it is possible to suppress deterioration of the toner due to rubbing, and to obtain high image quality for a long time. Can be maintained.

  In the image forming method using the non-magnetic one-component developing method, the present inventors use a toner in which the relationship between the toner carrier and the toner supply member satisfies a certain condition, and has an appropriate degree of aggregation and electrical resistivity. In this case, it has been found that the deterioration of the toner particles can be satisfactorily suppressed, and an advanced image can be obtained.

  Hereinafter, the present invention will be described in more detail.

  In the developing means, a frictional force is applied to the toner at a contact portion between the toner carrier and the toner supply member. Although the toner is charged by the frictional force, the external additive is embedded in the toner particles and the toner is deformed.

  As a result of intensive studies by the present inventors, it has been found that the stress applied to the toner is reduced by setting the diameter of the toner supply member larger than the diameter of the toner carrier. As a result, deterioration of the toner due to rubbing between the toner and the members (toner carrier and toner supply member) can be suppressed.

That is, in the present invention, when the diameter of the toner carrier is Rd (mm) and the diameter of the toner supply member is Rs (mm), it is necessary to satisfy the following relational expression (1).
1 ≦ Rs−Rd ≦ 10 (1)
The diameter Rd of the toner carrier and the diameter Rs of the toner supply member are expressed by the following relational expression (2).
2 ≦ Rs−Rd ≦ 8 (2)
Is preferably satisfied, and the following relational expression (3) is satisfied.
3 ≦ Rs−Rd ≦ 6 (3)
Is more preferably satisfied.

Further, it is preferable that the diameter Rd of the toner carrier and the diameter Rs of the toner supply member satisfy the following expressions (4) and (5), respectively.
10 ≦ Rd ≦ 14 (4)
12 ≦ Rs ≦ 17 (5)
If the value of Rd or Rs is excessively small, the number of rotations of the member must be increased in order to maintain the process speed. On the other hand, if the value of Rd or Rs is excessively large, the rotation speed of the member must be reduced in order to keep the supply amount of the toner at an appropriate level, and the frictional charge on the toner becomes weak, which may cause an image defect. Yes, not preferred. Rd or Rs more preferably satisfies the following formula (6) or (7).
10 ≦ Rd ≦ 13 (6)
14 ≦ Rs ≦ 17 (7)

  Further, the surface hardness of the toner carrier is preferably higher than the surface hardness of the toner supply member. In this case, when both diameters satisfy the above relationship, a particularly remarkable effect is obtained with respect to suppression of toner deterioration. . In addition, in the case of this relationship, the contact area between the toner carrier and the toner supply member becomes larger, so that the chargeability of the toner is increased, and the supply of the toner to the toner carrier is also improved.

  The surface hardness of the toner carrier is preferably 25 to 60 degrees in ASKER-C, and the surface hardness of the toner supply member is preferably 40 to 90 degrees in ASKER-F.

  On the other hand, the deterioration of the toner also depends on the degree of aggregation of the toner. The agglomeration degree of the toner is one of indexes indicating the fluidity. The non-magnetic one-component toner according to the present invention has an agglomeration degree of 5 to 30%, preferably 10 to 28%, and more preferably 15 to 25%. When the agglomeration degree of the toner is within this range, the stress of the rubbing applied between the toner carrier and the toner supply member is appropriately released, and the toner is appropriately charged by the rubbing. If the degree of aggregation of the toner is less than 5%, the toner will pass through the developing step without uniformly attaching to the toner carrier and the toner supply member. Therefore, when an image is formed, a sufficient image density cannot be obtained. Further, scattering of the toner in the developing device occurs. On the other hand, if the degree of aggregation of the toner exceeds 30%, the fluidity of the toner is insufficient, so that the toner is clogged between the toner regulating member and the toner carrier, and a smooth developing action is not performed. There is a tendency that the toner is rubbed more than necessary between the toner regulating member and the toner carrier or between the toner supply member and the toner carrier and deteriorates.

  The measurement of the degree of aggregation of the toner is performed as follows. A powder tester (manufactured by Hosokawa Micron Corporation) is used as a measuring device. As a measuring method, sieves of 100 mesh (mesh size 150 μm), 200 mesh (mesh size 75 μm), and 390 mesh (mesh size 38 μm) are set on the vibrating table in the order of widest mesh size. 5 g of the toner to be measured is placed on a 100 mesh. The vibration is started by setting the vibration amplitude to 0.6 mm and the vibration time to 15 seconds. When the vibration is completed, the mass of the toner remaining on each sieve is measured, and the degree of aggregation is calculated from the following equation (8).

  The degree of aggregation of the toner can be adjusted by appropriately selecting the colorant and the charge control agent contained in the toner, or by appropriately selecting the type and amount of the external additive, external addition conditions, and the like.

Further, the non-magnetic one-component toner according to the present invention has an electric resistivity in an electric field of 1 × 10 ⁴ V / cm of 1 × 10 ¹⁴ to 1 × 10 ¹⁸ Ωcm. By using a toner having an agglomeration degree and an electric resistivity within the above-mentioned range for the developing means in which the relationship between the diameter of the toner carrier and the diameter of the toner supply member is determined as described above, the toner can be sufficiently charged. The imparting property is obtained. Preferably the electrical resistivity of the toner is ^{1 × 10 14 ~1 × 10 17} Ωcm, more preferably ^{1 × 10 15 ~1 × 10 17} Ωcm. When the electric resistivity of the toner is smaller than 1 × 10 ¹⁴ Ωcm, it is difficult for the developing means used in the present invention to maintain a sufficient charge on the toner. Further, when the electric resistivity of the toner is larger than 1 × 10 ¹⁸ Ωcm, the charge distribution of the toner may be uneven. In any case, the roughness on the image tends to be remarkable.

  The electrical resistivity of the toner is measured by the following method. Since the toner used in the present invention is a powder, the electrical resistivity varies depending on the measurement conditions.

A cylinder having a lower electrode (diameter: 5 mm) is tapped with 0.3 to 1.0 g of the toner sample, and the upper electrode having a diameter of 15 mm is placed thereon, and the measurement is performed under a load of 350 g. At this time, after measuring the thickness of the sample, a voltage is applied from 0 V to 500 V and from 500 V to 0 V in 100 V steps. The electric field is calculated from the resistance value of the sample to be measured, the sample thickness, and the applied voltage, and the electric resistivity at 1 × 10 ⁴ V / cm is obtained.

  Further, the non-magnetic one-component toner has toner particles containing at least a binder resin, a colorant, and a release agent, and one or more external additives. Further, as the external additive, one or more silica fine powders treated with silicone oil are contained.

  In the present invention, the total addition amount (total addition amount) of all the external additives externally added to the toner is 0.5 to 5.0 parts by mass with respect to 100 parts by mass of the toner particles, and 1.0 to 5.0 parts by mass. It is preferably 3.0 parts by mass, more preferably 1.5 to 2.5 parts by mass. When the total amount of the external additives is less than 0.5 parts by mass, the ability to impart fluidity to the toner particles is not sufficient, and when the total amount exceeds 5.0 parts by mass, the external additives released from the toner particles are insufficient. An image defect may be caused by the agent contaminating the toner regulating member, the toner carrier, or the latent image carrier, which is not preferable because the effect of the present invention cannot be sufficiently exhibited.

Further, the toner of the present invention is characterized in that it contains silica fine powder treated with silicone oil as the external additive. The amount of such silica fine powder added to the toner is preferably 0.5 to 3.0 parts by mass, more preferably 1.0 to 2.5 parts by mass, per 100 parts by mass of the toner particles. preferable. When the amount of the silica fine powder added to the toner is within the above range, the stability of image density and the stability of image quality can be improved over a long period of time. The silica fine powder preferably has a BET specific surface area of 30 to 400 m ² / g. If the silica fine powder surface-treated with silicone oil is not used, the external additive is likely to adhere to the toner carrier, and the ability of the toner carrier to charge the toner is reduced.

  The non-magnetic one-component toner according to the present invention may have an external additive in addition to the silica fine powder treated with the silicone oil. In the present invention, organic or inorganic fine particles generally widely used as an external additive can be used. Specifically, examples of the inorganic fine particles include aluminum oxide, titanium oxide (anatase type, rutile type, Crystalline), metal oxides such as strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide; nitrides such as silicon nitride; carbides such as silicon carbide; calcium sulfate, barium sulfate, calcium carbonate Metal salts; fatty acid metal salts such as zinc stearate and calcium stearate; and carbon black. Further, as the organic fine particles, a homopolymer or a copolymer of a monomer component used for a binder resin for a toner such as styrene, acrylic acid, methyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate; And fine particles of the polymer obtained by an emulsion polymerization method or a spray drying method can be used.

  In addition, it is possible to use a plurality of these fine particles in combination as needed. The inorganic fine particles may or may not be hydrophobic. More preferably, it is subjected to a hydrophobic treatment. When the hydrophobic treatment is performed, either a wet method or a dry method may be used. Examples of the hydrophobizing agent include a silane coupling agent, a titanium coupling agent, an aluminate coupling agent, a zirconium aluminum coupling agent, and a silicone oil. Metal acid compounds such as titanium oxide, aluminum oxide, strontium titanate, cerium oxide, and magnesium oxide; nitrides such as silicon nitride; carbides such as silicon carbide; metal salts such as calcium sulfate, barium sulfate, and calcium carbonate; With respect to the above, a silane coupling agent is particularly preferably used as the hydrophobizing agent.

Among them, it is preferable to externally add titanium oxide. Titanium oxide to be used preferably has a specific surface area of 5~150m ² / g, further be used in conjunction with titanium oxide having a specific surface area of 5 to 50 m ² / g, titanium oxide having a specific surface area 80~150m ² / g Is preferred. Further, it is preferable that at least the titanium oxide having a specific surface area of 80 to 150 m ² / g is treated with a silane coupling agent. By adding titanium oxide having a specific surface area of 80 to 150 m ² / g, charge-up of the toner can be prevented, and sticking of the toner to the regulating member can be prevented. Further, by adding titanium oxide having a specific surface area of 5 to 50 m ² / g, an effect of stabilizing the charging of the toner can be obtained. By adding such titanium oxide, the deterioration of the toner can be suppressed even in a configuration such as the present invention in which the contact portion between the toner carrier and the toner supply member is easily subjected to stress.

Further, among the external additives used in the present invention, the BET specific surface area of at least one of the external additives is preferably 100 m ² / g or less.

  The toner particles constituting the non-magnetic one-component toner of the present invention contain at least a binder resin, a colorant, and a release agent. As the material contained in these toner particles, general materials conventionally used in toner can be used, and there is no particular limitation. Further, the toner and the toner particles in the present invention can be manufactured using a conventionally known method, and the manufacturing method thereof is not particularly limited.

  For example, as a method for producing the toner according to the present invention, a toner constituent material such as a binder resin, a colorant, a release agent, and, if necessary, a charge control agent is mixed with a pressure kneader, an extruder, or a media disperser. After kneading, a kneaded product is obtained by kneading, and after cooling, the kneaded product is pulverized by a jet mill or the like, and the pulverized product is further classified to obtain toner particles. A pulverization method of external addition can be used. In the pulverization method, when compounds such as various metal complexes that cause crosslinking during kneading are added at the same time when the resin is melt-kneaded, a crosslinking component can be generated in the binder resin.

  Further, as the toner particles according to the present invention, those subjected to a surface modification particle treatment can also be used. In particular, when toner particles are obtained by a pulverization method, the effect of surface modification is large. As a device for surface modification treatment, a high-speed air impact method such as a hybridization system (manufactured by Nara Machinery Co., Ltd.), a kryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), or an innomizer system (manufactured by Hosokawa Micron) was applied. Surface modification equipment using dry mechanochemical method such as surface modification equipment, mechano fusion system (manufactured by Hosokawa Micron), mechano mill (manufactured by Okada Seiko), Tisparcoat (manufactured by Nisshin Engineering), coatmizer (Freund) Surface-modifying apparatus that applies a wet coating method (manufactured by Sangyo Co., Ltd.), and an instantaneous heat-treating apparatus that instantaneously heat-treats toner particles, such as a surffusion system (manufactured by Nippon Pneumatic Industries, Ltd.). These can be used alone or in combination as appropriate.

  Further, as another method of the toner manufacturing method, a wet process in which a colorant, a charge control agent, and the like are mixed and dispersed in a solution including a solvent and a binder, and then the solution is introduced into an aqueous system, suspended or emulsified, and classified and dried. Can also be used.

  Further, as a method for producing the toner particles of the present invention, a polymerizable monomer constituting a binder resin is prepared by dissolving or dispersing a colorant, a release agent and, if necessary, other toner particle materials. A suspension polymerization method in which a monomer composition is prepared, the monomer composition is dispersed in an appropriate dispersion medium, and polymerization is performed using a polymerization initiator to obtain toner particles can also be suitably used. As the polymerizable monomer used when producing the toner of the present invention by the suspension polymerization method, a vinyl polymerizable monomer capable of radical polymerization is used. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

  As the monofunctional polymerizable monomer, styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butyl Styrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p Styrene derivatives such as -phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2 -Ethylhexyl acrylate And acrylic polymerizable monomers such as n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, and 2-benzoyloxyethyl acrylate Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl Methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate Methacrylic polymerizable monomers such as methacrylate and dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate and vinyl formate; vinyl methyl ether Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

  Examples of polyfunctional polymerizable monomers include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and tripropylene glycol. Diacrylate, polypropylene glycol diacrylate, 2,2'-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol Dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis (4- (methacryloxy diethoxy) phenyl) propane, Examples include 2,2′-bis (4- (methacryloxypolyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethanetetramethacrylate, divinylbenzene, divinylnaphthalene, and divinylether.

  In the present invention, the above-mentioned monofunctional polymerizable monomers are used alone or in combination of two or more, or the above-mentioned monofunctional polymerizable monomers and polyfunctional polymerizable monomers are used in combination. . Polyfunctional polymerizable monomers can also be used as crosslinking agents.

  As the polymerization initiator used in the polymerization of the above-mentioned polymerizable monomer, an oil-soluble initiator and / or a water-soluble initiator are used. For example, examples of the oil-soluble initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, and 1,1′-azobis (cyclohexane-1-carbonitrile). And azo compounds such as 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile; acetylcyclohexylsulfonyl peroxide, diisopropylperoxycarbonate, decanoyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide Oxide, acetyl peroxide, t-butylperoxy-2-ethylhexanoate, benzoyl peroxide, t-butylperoxyisobutyrate, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumylper Kisaido, t- butyl hydroperoxide, di -t- butyl peroxide, include peroxide initiators such as cumene hydroperoxide.

  Examples of the water-soluble initiator include ammonium persulfate, potassium persulfate, 2,2′-azobis (N, N′-dimethyleneisobutyroamidine) hydrochloride, and 2,2′-azobis (2-aminodinopropane) hydrochloride Salts, azobis (isobutylamidine) hydrochloride, sodium 2,2′-azobisisobutyronitrile sulfonate, ferrous sulfate or hydrogen peroxide. In the present invention, in order to control the degree of polymerization of the polymerizable monomer, a known chain transfer agent, polymerization inhibitor and the like may be further added and used.

  As the crosslinking agent used in the toner of the present invention, a compound having two or more polymerizable double bonds is used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate; divinylaniline and divinyl ether And divinyl compounds such as divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups. These can be used alone or as a mixture.

  The non-magnetic one-component toner according to the present invention contains a release agent which is a substance having a low softening point in toner particles. Examples of the release agent used in the toner of the present invention include polymethylene wax such as paraffin wax, polyolefin wax and microcrystalline wax; amide wax; higher fatty acid; long-chain alcohol; ester wax; Derivatives of

  Further, as the polymethylene wax, a low molecular weight alkylene polymer obtained by radical polymerization of alkylene under high pressure or polymerized under low pressure using a Ziegler catalyst or another catalyst; an alkylene polymer obtained by thermally decomposing a high molecular weight alkylene polymer A product obtained by separating and purifying a low-molecular-weight alkylene polymer by-produced when polymerizing alkylene; a component obtained by extracting and separating a specific component from a distillation residue of a hydrocarbon polymer obtained by an Age method from a synthesis gas comprising carbon monoxide and hydrogen. Examples include methylene wax and polymethylene wax obtained by extracting and separating a specific component from a synthetic hydrocarbon obtained by hydrogenating the distillation residue. An antioxidant may be added to these waxes.

  As the release agent to be used, those having a linear alkyl group having 15 to 100 carbon atoms are preferable, and linear alcohols, linear fatty acids, and linear fatty acids having such a linear alkyl group are preferable. A chain acid amide, a linear ester, or a montan derivative having a linear methylene chain having 15 to 100 carbon atoms is preferable.

  When toner particles are produced by a melt-kneading pulverization method, the release agent is preferably used in an amount of 1 to 20 parts by mass, more preferably 3 to 20 parts by mass, based on 100 parts by mass of the binder resin. When toner particles are directly produced in an aqueous medium using a polymerizable monomer composition, 1 to 30 parts by mass, more preferably 5 to 30 parts by mass, per 100 parts by mass of the polymerizable monomer. 20 parts by weight, and as a result, 1 to 30 parts by weight, more preferably 5 to 20 parts by weight, of the release agent is contained in the toner particles per 100 parts by weight of the binder resin formed from the polymerizable monomer. Is good.

  When the content of the release agent is less than 1 part by mass with respect to 100 parts by mass of the binder resin, the release effect by the wax is not sufficiently obtained, and as a result, the member is contaminated during continuous printing. . When the amount of the release agent exceeds 30 parts by mass, it is difficult to obtain the toner of the present invention having the above-mentioned aggregation degree.

  In a toner production method using a polymerization method as compared with a dry toner production method using a melt-kneading pulverization method, a large amount of a release agent is easily included in toner particles. The effect of preventing offset can be enhanced.

  The non-magnetic one-component toner of the present invention further contains a colorant in the toner particles. Examples of the colorant used in the toner of the present invention are shown below, but other colorants may be used.

  As the black colorant, carbon black, toned black using a yellow / magenta / cyan colorant shown below is used.

  As the yellow colorant, the following pigments and / or dyes can be preferably used. As the pigment, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complex methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 3, 7, 10, 12, 13, 14, 15, 17, 23, 24, 60, 62, 74, 75, 83, 93, 94, 95, 99, 100, 101, 104, 108, 109, 110,111,117,123,128,129,138,139,147,148,150,166,168,169,177,179,180,181,183,185,191: 1,191,192,193, 199 or the like is preferably used.

  Examples of the dye include C.I. I. Solvent Yellow 33, 56, 79, 82, 93, 112, 162, 163; I. Disperse Yellow 42, 64, 201, 211 and the like.

  As the magenta colorant, a condensed azo compound, a diketopyrrolopyrrole compound, an anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound, a thioindigo compound, and a perylene compound are used. Specifically, C.I. I. Pigment Red 2,3,5,6,7,23,48: 2,48: 3,48: 4,57: 1,81: 1,122,146,150,166,169,177,184,185 202, 206, 220, 221, 254; I. Pigment Violet 19 is preferred.

  As the cyan coloring agent, phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like are suitably used.

  These colorants can be used alone or as a mixture, and can also be used in a solid solution state. The colorant used in the present invention is selected from the viewpoints of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in toner. The colorant is used in an amount of 1 to 20 parts by mass per 100 parts by mass of the binder resin.

  The toner of the present invention may be used in combination with a charge control agent contained in the toner particles. The following substances control the toner to be negatively charged. Although an example is given, other things may be used. For example, organic metal compounds and chelate compounds are effective, and examples thereof include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids, and dicarboxylic acid-based metal compounds. Other examples include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids, and metal salts, anhydrides, esters, and phenol derivatives such as bisphenol. Furthermore, urea derivatives, metal-containing salicylic acid-based compounds, metal-containing naphthoic acid-based compounds, boron compounds, quaternary ammonium salts, calixarenes, resin-based charge control agents and the like can be mentioned.

  The charge control agent is preferably used in an amount of 0.01 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the binder resin.

  When the toner of the present invention is produced by a polymerization method, a condensation resin may be added to the toner. Although an example is given, other things may be used. Examples of the condensation resin used in the present invention include polyester, polycarbonate, phenol resin, epoxy resin, polyamide, and cellulose. More preferably, polyester is desired from the diversity of materials. The condensed resin is preferably used in an amount of 0.01 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the binder resin.

  The method for producing the toner particles used in the present invention can be produced by any method, and the following method can be used in addition to the method described above. For example, production of toner particles by an emulsion polymerization method typified by a soap-free polymerization method in which a monomer is directly polymerized in the presence of a soluble and water-soluble polymerization initiator to form toner particles is exemplified. In addition, production by an interfacial polymerization method such as a microcapsule production method, an in-situ polymerization method, a coacervation method, and the like are also included. Further, an interface association method of aggregating at least one kind of fine particles to obtain a particle having a desired particle size, as disclosed in JP-A-63-186253 or the like, may also be used.

In the toner used in the present invention, the toner particles preferably have an average circularity of 0.970 to 1.000 as measured by a flow-type particle image analyzer FPIA-1000 (manufactured by Toa Medical Electronics Co., Ltd.). The content of toner particles having an average circularity of less than 0.950 is preferably 15% by number or less. The average circularity is determined by the arithmetic mean of the circularities determined by the following equation.
(Circularity) = (perimeter of equivalent circle) / (perimeter of particle projected image)
In the above formula, the perimeter of the particle projection image is the length of the contour obtained by connecting the edge points of the binarized particle image, and the perimeter of the equivalent circle is the binarized particle. This is the length of the circumference of a circle having the same area as the image.

  In the contact developing method, the toner layer carried on the surface of the toner carrier comes into contact with the surface of the electrostatic latent image carrier, and the two members are strongly rubbed. Therefore, compared to the non-contact developing method, the toner particles tend to be flattened or damaged. Toner particles having an average circularity of less than 0.970 tend to be flattened and broken, and the flattened or broken toner particles change their charging characteristics. Causes a drop in sex. Further, by increasing the circularity, the transfer efficiency of the toner is also improved.

  There are several methods for measuring the particle size distribution of the toner. In the present invention, a multisizer (manufactured by Coulter Inc.) is used, and an interface for outputting a number average distribution and a volume average distribution is connected to a personal computer. As the electrolyte, a 1% NaCl aqueous solution is prepared using primary sodium chloride. As a measuring method, 0.1 to 1 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant to 30 to 50 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser. The volume distribution and the number distribution of the particles having a particle diameter of 2 to 30 μm are calculated by measuring the volume and the number of the toner particles by the above multisizer.

In the particle size distribution of the toner particles, the weight average particle diameter is preferably from 3 to 10 μm, and more preferably from 4.5 to 9 μm. Further, the coefficient of variation represented by the following equation is preferably 5 to 20%. In this case, the toner particles have a sharp particle size distribution, the charging by the regulating member is performed uniformly, and the developability is improved.
Coefficient of variation (%) = {(standard deviation based on weight) / (weight average particle size)} × 100

  Hereinafter, the image forming method of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view illustrating an example of the configuration of an image forming apparatus that suitably performs the image forming method of the present invention. In FIG. 1, reference numeral 3 denotes a charging roller which is a primary charging member for directly charging by contacting the photosensitive drum 1 as a latent image carrier, reference numerals 12 to 14 denote a bias power supply, and reference numeral 6 denotes a transfer material such as paper. Reference numeral 7 denotes a transfer member, reference numeral 5a denotes a heating roller for fixing, reference numeral 5b denotes a pressing roller for fixing, and reference numeral 4 denotes a cleaner.

  First, the surface of the latent image carrier (photoconductor drum) 1 rotating in the direction of the arrow is charged by the primary charging member 3 (charging step). In the present example, the primary charging member is the charging roller 3 having a basic configuration of a central metal core and a conductive elastic layer formed on the outer periphery thereof. The charging roller 3 abuts on the photosensitive drum 1 with a suppression force in the longitudinal direction thereof, and rotates following the rotation of the photosensitive drum 1. The charging roller 3 is connected to a bias power supply 12 for charging the surface of the photosensitive drum 1.

  As a preferable process condition when the charging roller 3 is used, the contact pressure of the roller is 0.05 to 5 N / cm. The applied voltage from the bias power supply 12 is a DC voltage or a DC voltage with an AC voltage superimposed thereon, and is not particularly limited. When an applied voltage obtained by superimposing an AC voltage on a DC voltage is used, the AC voltage is 0.5 to 5 dVpp, the AC frequency is 50 Hz to 5 kHz, and the DC voltage is ± 0.2 to ± 1.5 kV. When a DC voltage is used as the applied voltage, the DC voltage is ± 0.2 to ± 5 kV. In the present invention, it is preferable to use only a DC voltage.

  As a charging means other than the charging roller 3, there are a method using a charging blade and a method using a conductive brush. These contact charging means have the effects of requiring no high voltage and reducing the amount of ozone generated as compared with non-contact corona charging. The material of the charging roller and the charging blade as the contact charging means is preferably a conductive rubber, and a release coating may be provided on the surface thereof. As the release film, a nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), or the like can be used.

  After the charging step, the charged photosensitive drum surface is exposed by a laser or the like from the light emitting element 2 to form an electrostatic latent image on the photosensitive drum 1 according to an information signal (latent image forming step). At a position where the photosensitive drum 1 and the developing roller 9 (toner carrier) are in contact, the electrostatic latent image is developed (visualized) with a non-magnetic one-component toner to form a toner image (developing step).

  In the image forming method of the present invention, the toner carrier may rotate in the same direction at the portion facing the photosensitive drum, or may rotate in the opposite direction. When the rotation is in the same direction, the peripheral speed of the toner carrier is preferably set to be 1.05 to 3.0 times the peripheral speed of the photoconductor.

  If the peripheral speed ratio of the toner carrier to the photoconductor drum is less than 1.05, the supply of toner to the photoconductor may be insufficient, and a good solid image may not be obtained. If the peripheral speed ratio exceeds 3.0, deterioration of the toner due to mechanical stress and adhesion of the toner to the toner carrier occur, which is not preferable.

The photosensitive _{drum, a-Se, CdS, ZnO} 2, OPC ( organic photoconductor) photosensitive drum or photosensitive belt having a photoconductive insulating material layer, such as a-Si (amorphous silicon) is preferably used . The binder resin of the organic photosensitive layer in the OPC photosensitive member is not particularly limited, but polycarbonate resin, polyester resin, and acrylic resin are particularly excellent in transferability, fusion of the toner to the photosensitive member, and external additives. Is preferred because filming hardly occurs. Further, a surface layer in which a lubricant powder having high lubricity and water repellency is dispersed in an arbitrary binder may be provided on the surface of the photoconductor elastic layer.

  Although there is no particular limitation on the lubricant, various fluororubbers, fluoroelastomer, carbon fluoride and polytetrafluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer and tetrafluoroethylene-perfluorocarbon in which fluorine is bonded to graphite or graphite. Fluorine compounds such as fluoroalkyl vinyl ether copolymers, silicone resin particles, silicone compounds such as silicone rubber and silicone elastomer, polyethylene, polypropylene, polystyrene, acrylic resins, polyamide resins, phenol resins, epoxy resins and the like are preferably used.

  Further, a conductive agent may be appropriately added to the binder of the surface layer to control the resistance. Examples of the conductive agent include various conductive inorganic particles and carbon black, an ionic conductive agent, a conductive resin, and a conductive particle-dispersed resin.

  Next, the developing step in the image forming method used in the present invention will be described. The developing step used in the present invention is a step of visualizing (developing) the electrostatic latent image formed on the surface of the photosensitive drum 1 with the non-magnetic one-component toner by a developing unit to form a toner image. The developing device as a developing unit used in the present invention includes a toner container 10 containing a non-magnetic one-component toner 32, a stirring member 11 for stirring the toner contained in the toner container 10, and a toner contained in the toner container 10. And a toner supply member 8 for supplying the toner contained in the toner container 10 to the developing roller 9, and a toner amount on the developing roller 9. A regulating member 33 that regulates and gives charge to the toner.

  A developing bias power source 14 is connected to the developing roller 9. A bias power source (not shown) is also connected to the application roller 8. When a negatively-chargeable toner is used, the bias power is more negative than the developing bias, and when a positively-chargeable toner is used, the bias power is more positive than the developing bias. The voltage is set. The transfer member 7 is connected to a transfer bias power supply 13 having a polarity opposite to that of the photosensitive drum 1.

  In the developing device used in the present invention, the toner carrier 9 has a cylindrical shape, and its surface is provided in contact with the surface of the photosensitive drum 1. The toner carrier 9 is rotatable in a forward direction or a reverse direction of the rotation direction of the photosensitive drum 1.

  In the image forming method of the present invention, it is essential that the toner carrier 9 and the surface of the photosensitive drum 1 serving as an electrostatic latent image carrier are in contact with each other. This is because the toner is directly supplied to the surface of the latent image carrier in the contact developing method as compared with the case of non-contact, so that adverse effects such as scattering of the toner on the image are less likely to occur. As a result, lines, characters, and the like can be printed with good reproducibility.

  As the contact developing method, it is preferable to use an elastic roller having an elastic layer on the surface as the toner carrier 9, and a method in which a developer is coated on the elastic roller surface or the like and brought into contact with the surface of the photosensitive drum 1 can be used. . In this case, development is performed by the action of the developing bias applied to the photosensitive drum 1 and the elastic roller (toner carrier) that comes into contact with the surface of the photosensitive drum 1 via the toner. At this time, since it is necessary to provide a potential difference between the elastic roller and the photosensitive drum, the elastic rubber of the elastic roller is resistance-controlled in the medium resistance region to prevent conduction with the surface of the photosensitive member while maintaining an electric field, or For example, a method in which a thin insulating layer is provided on the surface layer of the conductive roller can be used. In addition, as a toner carrier, a conductive layer is provided on the conductive roller on a conductive resin sleeve on which the side facing the surface of the photosensitive drum 1 is coated with an insulating material, or on a side not facing the photosensitive body with an insulating sleeve. It is also possible to use one having the configuration. Further, it is also possible to employ a configuration in which a rigid roller is used as the toner carrier 9 and the latent image carrier is a flexible material such as a belt.

As described above, the elastic roller preferably has a hardness of 25 to 60 degrees (ASKRE-C / load of 1 kg), and more preferably has a hardness of 30 to 60 degrees. The resistance of the toner carrier is preferably in the range of about 10 ² to 10 ⁹ Ωcm in terms of volume resistance. If the resistance of the toner carrier is lower than 10 ² Ωcm, for example, if there is a pinhole on the surface of the photoconductor, an overcurrent may flow. On the other hand, when the resistance of the toner carrier is higher than 10 ⁹ Ωcm, the toner is likely to be charged up due to frictional charging, and the image density is likely to be reduced.

  When the surface roughness Ra (μm) of the toner carrier 9 is set to be 0.2 to 3.0, both high image quality and high durability can be achieved. The surface roughness Ra correlates with the toner carrying ability and the toner charging ability. If the surface roughness Ra of the toner carrier 9 exceeds 3.0 μm, it becomes difficult not only to reduce the thickness of the developer layer on the toner carrier 9 but also to improve the image quality because the chargeability of the developer is not improved. It will be difficult. By controlling the surface roughness Ra of the toner carrier to 3.0 μm or less, the toner carrying ability on the surface of the toner carrier 9 is suppressed, the developer layer on the toner carrier is made thinner, and Since the number of times of contact between the body and the toner can be increased and the chargeability of the toner is also improved, the image quality is synergistically improved. On the other hand, if the surface roughness Ra is smaller than 0.2 μm, it becomes difficult to control the amount of developer coating.

  In the present invention, the surface roughness Ra of the toner carrier is measured using a surface roughness measuring device (Surfcoder SE-30H, manufactured by Kosaka Laboratory Co., Ltd.) based on JIS surface roughness "JIS B0601". Center line average roughness. Specifically, a 2.5 mm portion as the measurement length a is extracted from the roughness curve in the direction of the center line, the center line of the extracted portion is the X axis, the longitudinal magnification direction is the Y axis, and the roughness curve is When y = f (x), the value obtained by the following equation (9) is expressed in micrometers (μm).

  The application roller 8 as the toner supply member is an elastic roller having a cylindrical shape having a rotation axis parallel to the rotation axis of the toner carrier. The application roller 8 is provided in contact with the surface of the toner carrier, and the contact portion is located on the toner carrier surface at a position upstream of the contact position between the toner carrier and the photosensitive drum 1 in the rotational direction. The application roller 8 is rotatable, and preferably rotates in a direction opposite to the rotation direction of the toner carrier. As a result, the toner 32 adheres to the developing roller 9 and the toner is charged by friction with the developing roller 9.

  The toner coating amount on the developing roller 9 is controlled by a regulating blade 33 as a toner regulating member. The regulating blade 33 is in contact with the developing roller 9 via a toner layer. At this time, the contact pressure between the regulating blade 33 and the developing roller 9 is preferably in the range of 0.05 to 0.5 N / cm as the linear pressure in the generatrix direction of the developing roller 9.

  The linear pressure is a load applied per length of the blade 33. For example, when a load of 1.2 N is applied to the blade 33 having a contact length of 1 m and the blade 33 is brought into contact with the developing roller 9, The linear pressure is 1.2 N / m. If the linear pressure is less than 0.05 N / cm, uniform triboelectric charging becomes difficult in addition to the control of the amount of toner coating, which causes fog to deteriorate. On the other hand, if the linear pressure is larger than 0.5 N / cm, the toner particles receive an excessive load, so that the deformation of the toner particles and the fusion of the toner to the regulating blade 33 or the developing roller 9 are likely to occur, Not preferred.

  The free end of the regulating blade 33 may have any shape, for example, besides a linear cross-section, an L-shaped bent near the tip, or a bulged shape near the tip. Is preferably used.

  In the present invention, for the elastic toner regulating member such as the regulating blade 33, it is preferable to select a material of a triboelectric series suitable for charging the toner to a desired polarity, and it is preferable to use silicone rubber, urethane rubber, NBR, or the like. Rubber elastic bodies, synthetic resin elastic bodies such as polyethylene terephthalate, and metal elastic bodies such as stainless steel, steel, and phosphor bronze can be used. Further, a composite thereof may be used. Further, as such a toner regulating member, a rigid metal blade or the like may be used in addition to the elastic blade for press-applying the toner. More specifically, a toner regulating member (regulating blade 33) is formed by using a metal elastic body such as stainless steel, steel, phosphor bronze, or the like as a base material, and adhering or coating a resin on the contact portion with the developing roller 9 and in the vicinity thereof. ) Is preferably used.

  Further, an organic substance or an inorganic substance may be added to the toner regulating member, may be melted and mixed, or may be dispersed. For example, the chargeability of the toner can be controlled by adding metal oxides, metal powders, ceramics, carbon allotropes, whiskers, inorganic fibers, dyes, pigments, surfactants, and the like. In particular, when the elastic body is a molded body such as rubber or resin, fine particles of metal oxide such as silica, alumina, titania, tin oxide, zirconia, and zinc oxide, carbon black, a charge control agent generally used for toner And the like.

  Further, by applying a DC voltage and / or an AC voltage to the toner regulating member, the uniform thin layer coating property and the uniform charging property are further improved due to the loosening action on the toner, and a sufficient image density can be achieved. Good quality images can be obtained.

  Further, in the image forming method of the present invention, in particular, by combining with a developing system in which a digital latent image is formed on the photosensitive drum 1, it is possible to faithfully develop a dot latent image without disturbing the latent image. It becomes.

  The visualized toner image is transferred to the transfer material 6 by the transfer member 7 (transfer step), and is fixed by passing between the heating roller 5a and the pressure roller 5b (fixing step). The heating / pressing fixing means is not limited to the heat roller system having a basic structure of a heating roller 5a having a built-in heating element such as a halogen heater as shown here and a pressing roller 5b of an elastic body pressed with pressure. A method of fixing by heating with a heater via a film is also used. Further, in the apparatus shown in FIG. 1, the transfer is directly performed from the photosensitive drum to the transfer material without using the intermediate transfer member, but the transfer from the photosensitive drum to the transfer material is performed once via the intermediate transfer member. May be performed.

  On the other hand, the transfer residual toner remaining on the photosensitive drum 1 without being transferred is collected by a cleaner 4 having a cleaning blade in contact with the surface of the photosensitive drum 1, and the photosensitive drum 1 is cleaned and Of the image forming cycle.

  Next, a case where an intermediate transfer belt is used as an intermediate transfer member in the transfer step will be described with reference to FIG. In FIG. 2, reference numeral 15 denotes an intermediate transfer belt, reference numerals 16 and 25 denote rollers around which the intermediate transfer belt 15 is wound, reference numeral 17 denotes a transfer material, reference numeral 24 denotes a primary transfer roller, reference numeral 19 denotes a secondary transfer roller, and reference numeral 18 denotes a secondary transfer roller. The next transfer opposing roller, reference numerals 20 to 22 denote a bias power source, and reference numeral 23 denotes a cleaning charging member. The same members as those in FIG. 1 are denoted by the same reference numerals.

  In FIG. 2, on the surface of the latent image carrier (photosensitive drum) 1, electrostatic latent images corresponding to toner images of the respective colors (first to fourth colors) forming a full-color image are sequentially formed. A known color developing device (not shown) capable of developing with the above-mentioned toner sequentially develops with the corresponding color toner to obtain a toner image.

  The toner image formed and carried on the photosensitive drum 1 is passed through a nip portion between the photosensitive drum 1 and the intermediate transfer belt 15 by a primary transfer bias applied from the primary transfer roller 24 to the intermediate transfer belt 15. The primary transfer is sequentially performed on the outer peripheral surface of the intermediate transfer belt 15 by the formed electric field. A primary transfer bias for sequentially superimposing and transferring the toner images of the first to fourth colors from the photosensitive drum 1 to the intermediate transfer belt 15 has a polarity opposite to that of the toner, and is applied from a bias power supply 22.

  In the primary transfer step of the first to fourth color toner images to the intermediate transfer belt 15, the secondary transfer roller 19 and the cleaning charging member 23 can be separated from the intermediate transfer belt 15. The secondary transfer roller 19 is supported in parallel with the secondary transfer opposing roller 18 and is disposed on the lower surface of the intermediate transfer belt 15 so as to be separated therefrom.

  The transfer (secondary transfer) of the composite color toner image obtained by sequentially transferring the toner images of the first to fourth colors onto the intermediate transfer belt 15 to the transfer material 17 is performed as follows. . First, when the secondary transfer roller 19 is brought into contact with the intermediate transfer belt 15, the transfer material 17 is fed at a predetermined timing to a contact nip between the intermediate transfer belt 15 and the secondary transfer roller 19, and the secondary transfer is performed. A bias is applied to the secondary transfer roller 19 from a bias power supply 20. The composite color toner image is secondarily transferred from the intermediate transfer belt 15 to the transfer material 17 by the secondary transfer bias.

  After the transfer of the composite color toner image onto the transfer material 17, the cleaning charging member 23 is brought into contact with the intermediate transfer belt 15, and a bias having a polarity opposite to that of the photosensitive drum 1 is applied from the bias power supply 21. Then, a charge having a polarity opposite to that of the photosensitive drum 1 is applied to toner (transfer residual toner) remaining on the intermediate transfer belt 15 without being transferred to the transfer material 17. Next, the intermediate transfer belt 15 is cleaned by transferring the transfer residual toner to the photosensitive drum 1 in a nip portion with the photosensitive drum 1 and in the vicinity thereof.

  The intermediate transfer belt 15 includes a belt-shaped base layer and a surface treatment layer provided on the base layer. The surface treatment layer may be composed of a plurality of layers. Rubber, elastomer, and resin can be used for the base layer and the surface treatment layer. For example, rubber and elastomers include natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, acrylonitrile butadiene rubber, Urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin rubber, acrylic rubber, silicone rubber, fluorine rubber, polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber, and thermoplastic elastomers (eg, polystyrene, polyolefin, One or two or more selected from the group consisting of polyvinyl chloride, polyurethane, polyamide, polyester, fluororesin, etc.) can be used. However, it is not limited to the above materials. In addition, as the resin, a resin such as a polyolefin resin, a silicone resin, a fluorine resin, and a polycarbonate can be used. Copolymers or mixtures of these resins may be used.

  As the base layer, the above-mentioned rubber, elastomer, or resin can be used in the form of a film. A material obtained by coating, dipping, or spraying the above-mentioned rubber, elastomer, or resin on one or both surfaces of a core layer in the form of a woven fabric, a nonwoven fabric, a thread, or a film may be used.

  The material constituting the core layer is, for example, unnatural fibers such as cotton, silk, hemp and wool; regenerated fibers such as chitin fibers, alginate fibers and regenerated cellulose fibers; semi-synthetic fibers such as acetate fibers; polyester fibers and nylon fibers. Synthetic fibers such as acrylic fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, polyurethane fibers, polyalkylparaoxybenzoate fibers, polyacetal fibers, aramid fibers, polyfluoroethylene fibers and phenol fibers; carbon fibers Or one or more selected from the group consisting of inorganic fibers such as glass fibers and boron fibers; and metal fibers such as iron fibers and copper fibers. Of course, it is not limited to the above materials.

  Further, in order to adjust the resistance value of the intermediate transfer belt 15, a conductive agent may be added to the base layer and the surface treatment layer. The conductive agent is not particularly limited, for example, carbon, metal powder such as aluminum or nickel, metal oxide such as titanium oxide, and quaternary ammonium salt-containing polymethyl methacrylate, polyvinyl aniline, polyvinyl pyrrole, One or more selected from the group consisting of conductive polymer compounds such as polydiacetylene, polyethyleneimine, boron-containing polymer compounds and polypyrrole can be used. However, it is not limited to the above conductive agent.

  Further, a lubricant may be added as necessary to increase the slipperiness of the surface of the intermediate transfer belt 15 and improve the transferability. Although there is no particular limitation on the lubricant, various fluororubbers, fluoroelastomers, carbon fluoride and polytetrafluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer and tetrafluoroethylene in which fluorine is bonded to graphite or graphite Fluorine compounds such as perfluoroalkyl vinyl ether copolymers, silicone compounds such as silicone resins, silicone rubbers and silicone elastomers, polyethylene, polypropylene, polystyrene, acrylic resins, polyamide resins, phenol resins and epoxy resins are preferably used.

  Further, as another image forming apparatus capable of performing the image forming method of the present invention, there is a full-color image forming apparatus as shown in FIG.

  In FIG. 3, each latent image carrier (photosensitive drum) and each developing device are installed in a tandem system, that is, along the process progress direction (rotation direction) of the intermediate transfer belt. The image forming apparatus of the present embodiment includes a developing device having toner carrying members (developing rollers) 9a to 9d and toner supplying members 8a to 8d around the photosensitive drums 1a, 1b, 1c, and 1d, respectively, and charging rollers 3a to 3d. 3d, latent image forming means 2a to 2d, transfer rollers 24a to 24d, and cleaning means 4a to 4d. The photoconductor drum, the developing device, the charging roller, the latent image forming unit, and the cleaning unit may be integrally formed to constitute a process cartridge.

  The primary transfer is performed by applying a bias to each of the transfer rollers 24a, 24b, 24c, and 24d. With this bias, the toner images of the first to fourth colors of the respective developing units are sequentially superimposedly transferred from the photosensitive drums 1a, 1b, 1c, and 1d to the intermediate transfer belt 35.

  The transfer of the composite color toner image transferred onto the intermediate transfer belt 35 to the transfer material 34 is performed as follows. That is, the secondary transfer roller 29 is brought into contact with the intermediate transfer belt 35, the transfer material 34 is fed to the contact nip between the intermediate transfer belt 35 and the secondary transfer roller 29 at a predetermined timing, and the secondary transfer bias is reduced. The bias power is applied to the secondary transfer roller 29. With this secondary transfer bias, the composite color toner image is secondarily transferred from the intermediate transfer belt 35 to the transfer material 34. Note that reference numeral 26 denotes a secondary transfer facing roller, and reference numerals 27 and 28 denote rollers around which the intermediate transfer belt 35 is wound.

  The composite color toner image transferred onto the transfer material 34 is fixed as the transfer material passes between the heating roller 30 and the pressure roller 31 to become a permanent image. The heating / pressing fixing means is not limited to the heat roller system having a basic configuration of a heating roller 30 having a built-in heating element such as a halogen heater shown here and a pressing roller 31 of an elastic body pressed in contact with suppression. A method of fixing by heating with a heater via a film is also used.

  FIG. 4 shows an apparatus in which the intermediate transfer belt is changed to a transport belt 40 in the image forming apparatus of FIG. In this apparatus, a toner image is directly transferred to a transfer material carried and conveyed by the conveyance belt 40 in each developing unit, and a multi-toner image is formed.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

<Production Example 1 of Toner Particle>
After adding 450 parts by mass of 0.1 mol / liter-Na ₃ PO ₄ aqueous solution to 400 parts by mass of ion-exchanged water and heating to 50 ° C., using a TK homomixer (manufactured by Tokushu Kika Kogyo), 10,000 rpm. And stirred. 68 parts by mass of 1.0 mol / liter-CaCl ₂ aqueous solution was added thereto to obtain an aqueous medium containing calcium phosphate.

on the other hand,
(Monomer) 75 parts by mass of styrene
n-Butyl acrylate 25 parts by mass (colorant) Yellow colorant (CI Pigment Yellow 180) 6 parts by mass (charge control agent) Aluminum di-tert-butylsalicylate compound 1 part by mass (polar resin) Saturated polyester 10 parts by mass Department
(Polycondensate of propylene oxide-modified bisphenol A and isophthalic acid, Tg = 70 ° C., Mw = 12000, Mw / Mn = 2.4, acid value: 10)
(Releasing agent) 15 parts by mass of behenyl stearate (crosslinking agent) 1.2 parts by mass of divinylbenzene The above material is heated to 50 ° C., and is uniformed at 9000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). Was dissolved and dispersed. In this, 3 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was dissolved to prepare a polymerizable monomer composition.

  The polymerizable monomer composition was charged into the aqueous medium, and the mixture was stirred at 8000 rpm with a TK homomixer at 50 ° C. under a nitrogen atmosphere to granulate the polymerizable monomer composition. Thereafter, while stirring with a paddle stirring blade, the temperature was raised to 60 ° C. in 2 hours and reacted for 5 hours. Thereafter, the temperature was raised to 80 ° C. at a rate of 40 ° C./hr, and the reaction was performed for 5 hours. After completion of the polymerization reaction, residual monomers were distilled off under reduced pressure, and after cooling, hydrochloric acid was added and the mixture was stirred for 6 hours. Thereafter, the mixture was filtered, washed with ion-exchanged water, and dried to obtain yellow toner particles 1. The yellow toner particles 1 had a weight average particle size of 6.8 μm and an average circularity of 0.989.

<Production Example 2 of Toner Particle>
Magenta toner particles 1 were produced by the same method as in Production Example 1 except that the colorant was changed to magenta colorant (CI Pigment Red 150) in Production Example 1 of the toner particles. Magenta toner particles 1 had a weight average particle size of 6.7 μm and an average circularity of 0.985.

<Production Example 3 of Toner Particle>
Cyan toner particles 1 were produced using the same method as in Production Example 1 except that the colorant in Production Example 1 for toner particles was changed to a cyan colorant (CI Pigment Blue 15: 3). Cyan toner particles 1 had a weight average particle size of 6.6 μm and an average circularity of 0.990.

<Production Example 4 of Toner Particle>
Black toner particles 1 were produced in the same manner as in Production Example 1 except that the coloring agent was changed to carbon black and the addition amount was changed to 10 parts by mass. The black toner particles 1 had a weight average particle size of 6.7 μm and an average circularity of 0.984.

<Production Example 5 of Toner Particle>
Styrene, 100 parts by mass of styrene-acrylic resin (Mn = 7200, Mw = 42000, THF insoluble content = 13%, glass transition point = 58 ° C.) obtained by polymerizing n-butyl acrylate,
5 parts by mass of yellow colorant (CI Pigment Yellow 180) 3 parts by mass of aluminum di-tert-butylsalicylate compound 11 parts by mass of behenyl stearate are added and melt-kneaded by a twin-screw extruder, followed by pulverization and yellow pulverization. I got something. Heat and mechanical impact were applied to the pulverized product using a surface reformer to modify the toner composition and perform a spheroidizing treatment. The spheroidized toner composition was classified by a multi-stage classifier to obtain yellow toner particles 2. The yellow toner particles 2 had a weight average particle size of 6.8 μm and an average circularity of 0.941.

<Production Example 6 of Toner Particle>
Magenta toner particles 2 were produced by the same method as in Production Example 5 except that the colorant was changed to magenta colorant (CI Pigment Red 150) in Production Example 5 of toner particles. The magenta toner particles 2 had a weight average particle size of 6.6 μm and an average circularity of 0.937.

<Production Example 7 of Toner Particle>
Cyan toner particles 2 were produced in the same manner as in Production Example 5 except that the coloring agent was changed to cyan colorant (CI Pigment Blue 15: 3) in Production Example 5 of toner particles. Cyan toner particles 2 had a weight average particle size of 6.6 μm and an average circularity of 0.950.

<Production Example 8 of Toner Particle>
Black toner particles 2 were produced in the same manner as in Production Example 5 except that the colorant was changed to carbon black and the amount added was 10 parts by mass. The black toner particles 2 had a weight average particle size of 6.9 μm and an average circularity of 0.942.

<Example of process cartridge>
Image formation was performed using a laser beam printer (Canon: LBP-5500 modified machine) using an electrophotographic process of the non-magnetic one-component contact developing system shown in FIG. As the process cartridge, one having a configuration excluding the transfer roller, the bias applying unit, the fixing heating roller 5a and the fixing pressing roller 5b from the configuration of FIG. 1 was used. In this example, the following (a) to (h) were modified with respect to the printer.
(A) The process speed was changed to 95 mm / s.
(B) The charging method of the apparatus was direct charging in which a rubber roller was brought into contact to perform charging, and the applied voltage was a DC component (−450 V).
(C) The toner carrier was changed to a medium resistance rubber roller (diameter: 12 mm, ASKER-C hardness: 45 degrees, resistance: 10 ⁵ Ω · cm) made of silicone rubber in which carbon black was dispersed, and was brought into contact with the photoconductor.
(D) The rotation of the toner carrier was in the same direction at the contact portion with the photoconductor, and the peripheral speed was driven to be 135 mm / s.
(E) The following photoreceptors were used.

A photoreceptor was prepared by using an Al cylinder as a substrate and sequentially laminating layers having the following constitutions by dip coating.
(1) Conductive coating layer: mainly composed of tin oxide and titanium oxide powder dispersed in a phenol resin. 15 μm thick.
(2) Undercoat layer: mainly composed of modified nylon and copolymerized nylon. The film thickness is 0.6 μm.
(3) Charge generation layer: mainly composed of a dispersion of a titanyl phthalocyanine pigment having absorption in a long wavelength region in a butyral resin. The film thickness is 0.6 μm.
(4) Charge transporting layer: mainly composed of a hole-transporting triphenylamine compound dissolved in a polycarbonate resin (number average molecular weight Mn = 20,000 by Ostwald viscosity method) at a mass ratio of 8:10. Film thickness 20 μm.

The peripheral speed of the photoconductor was set at 95 mm / s.
(F) As a toner supply member, an elastic roller made of urethane foam rubber (50 to 100 cells per inch, ASKER-F hardness of 55 degrees, diameter of 16 mm) is used as a toner supply member, and is brought into contact with the toner carrier. I let it. The rotation direction of the elastic roller was reversed at the contact portion with the toner carrier, and the peripheral speed was set to 95 mm / s.
(G) A stainless steel blade coated with a resin was used as a means (toner regulating member) for controlling the coat layer of the toner on the toner carrier.
(H) The applied voltage at the time of development was only the DC component (-250 to -300 V).

  The remodeled device uniformly charges the latent image carrier using a roller charger (only DC is applied). After charging, an image is exposed to a laser beam to form an electrostatic latent image by exposing the image portion to a visible image with toner, and then the toner image is transferred to a transfer material by a transfer roller to which a voltage is applied.

<Example 1>
100 parts by mass of each of yellow toner particles 1, magenta toner particles 1, cyan toner particles 1 and black toner particles 1 obtained in Production Examples 1 to 4 of toner particles, The additives were mixed using a Henschel mixer 10B (manufactured by Mitsui Miike Koki Co., Ltd.) under the conditions of a rotation speed of 3000 rpm and a stirring time of 4 minutes to obtain a negative frictionally chargeable color toner of each color. Table 1 shows the degree of aggregation and the electrical resistivity of the obtained color toners in an electric field of 1 × 10 ⁴ V / cm.

170 g of each of these toners was filled in the developing device of the above process cartridge into 170 g for each color to obtain a four color process cartridge. These process cartridges were mounted on the full-color image forming apparatus shown in FIG. The description of the full-color image forming apparatus is as described above. 15,000 sheets of 75 g / m ² A4 plain paper in each environment of normal temperature and normal humidity (23 ° C./50% RH), low temperature and low humidity (15 ° C./10% RH), and high temperature and high humidity (30 ° C./80% RH) A continuous print test was performed. In this test, the printing speed was set to 16 sheets per minute in A4 size, and the printing ratio of each color to the paper area was set to 2%. With respect to the image obtained after the end of the test, occurrence of streak-like image omission in the halftone image and occurrence of toner sticking were evaluated based on the following evaluation methods. The evaluation results are shown in Tables 3 and 4.

  In all Examples and Comparative Examples, the evaluation results at the initial stage of printing based on the following evaluation methods were all good.

[Evaluation method]
(1) Roughness Roughness is shading that appears on an image. After the continuous printing test of 15,000 sheets, all solid images of each color were printed using the above-mentioned plain paper sufficiently conditioned in each test environment. The reflection density is measured at a predetermined 10 points in the image by using a reflection densitometer RD918 (manufactured by Macbeth), and the difference between the average of 5 points of high density and the average of 5 points of low density is determined and evaluated according to the following criteria. did.
A: Density difference 0.5% or less B: Density difference more than 0.5% to 1.0% or less C: Density difference more than 1.0% to 1.5% or less D: Density difference more than 1.5% to 2 0.0% or less E: Density difference exceeds 2.0%

(2) Streak-like image omission in halftone image After completion of the continuous printing test for 15,000 sheets, all halftone images of each color were printed using the above-mentioned plain paper sufficiently conditioned in each test environment. In this image, the number of white streaks having a width of 0.5 mm or less was counted, and judgment was made based on the number.
A: No white streaks are generated.
B: The number of white stripes is 1 to 3.
C: The number of white stripes is 4 to 7.
D: The number of white streaks is 8 to 10.
E: White streaks having 11 or more white streaks or exceeding 0.5 mm in width are generated.

(3) Observation of Toner Fixing State of Toner Controlling Member After the continuous printing test of 15,000 sheets under normal temperature and normal humidity, the toner controlling member was observed.
A: No adhesion of toner is observed.
B: The toner is slightly fixed.
C: A small amount of toner is fixed.
D: A large amount of toner is fixed.

<Examples 2 to 7>
In Example 1, a color toner was manufactured and evaluated in the same manner as in Example 1 except that the formulation of the external additive added to the toner particles of each color was changed to the external additive formulations 2 to 6 and 10 shown in Table 2. Was. Table 1 shows the degree of aggregation and the electrical resistivity at an electric field of 1 × 10 ⁴ V / cm for each color toner, and Tables 3 and 4 show the evaluation results.

<Comparative Examples 1 to 3>
In Example 1, a color toner was manufactured and evaluated in the same manner as in Example 1 except that the formulation of the external additive added to the toner particles of each color was changed to the external additive formulations 7 to 9 shown in Table 2. Table 1 shows the degree of aggregation and the electrical resistivity at an electric field of 1 × 10 ⁴ V / cm for each color toner, and Tables 3 and 4 show the evaluation results.

  Table 3 shows the evaluation results of Examples 1 to 7 and Comparative Examples 1 to 3.

  From these examination results (Tables 3 and 4), it was found that generally good images were obtained in Examples 1 to 7. Therefore, using the toner of Example 1 as a reference, the effect of the difference in diameter between the toner carrier and the elastic roller in the developing device on the image was examined as follows.

<Example 8>
In Example 1, the diameter of the developing roller 9 (toner carrier) of the developing device was changed to 14 mm, and the diameter of the toner supply member 8 was changed to 16 mm. Only the diameter was changed so that the material, hardness, number of cells, and resistance of the toner carrier and the toner supply member did not change. Further, the image forming conditions such as the process speed and the applied voltage at the time of development were not changed. The color toner used in Example 1 was filled in such an image forming apparatus, and the same evaluation as in Example 1 was performed.

<Examples 9 to 13>
The same evaluation as in Example 1 was performed except that the diameters of the developing roller and the toner supply member were changed as shown in Table 5 in Example 1. Tables 6 and 7 show the evaluation results.

<Comparative Examples 4 to 10>
The same evaluation as in Example 1 was performed except that the diameters of the developing roller and the toner supply member were changed as shown in Table 5 in Example 1. Tables 6 and 7 show the evaluation results.

FIG. 1 is a schematic cross-sectional view illustrating an example of a configuration of an image forming apparatus that suitably performs an image forming method of the present invention. FIG. 1 is a schematic cross-sectional view illustrating a partial configuration of an image forming apparatus using an intermediate transfer belt that suitably performs an image forming method of the present invention. FIG. 1 is a schematic cross-sectional view illustrating an example of a configuration of a tandem-type full-color image forming apparatus that preferably performs an image forming method of the present invention. FIG. 2 is a schematic cross-sectional view illustrating another example of the configuration of a tandem-type full-color image forming apparatus that suitably performs the image forming method of the present invention.

Claims (8)

A charging step of charging the surface of the latent image carrier, a latent image forming step of forming an electrostatic latent image on the surface of the charged latent image carrier, and a non-magnetic one-component toner using the developing means to develop the electrostatic latent image. A developing step of visualizing the toner image to form a toner image, a transfer step of transferring the toner image onto a transfer material with or without an intermediate transfer member, and a fixing step of fixing the toner image on the transfer material. An image forming method comprising:
The developing means includes: a toner container containing a non-magnetic one-component toner; a rotatable cylindrical member provided in contact with the latent image carrier and carrying the non-magnetic one-component toner and transporting the non-magnetic one-component toner to the latent image carrier A toner carrier; provided on the surface of the toner carrier in contact with the toner carrier on the upstream side in the rotational direction from the contact position between the toner carrier and the latent image carrier, and having a rotation axis parallel to the rotation axis of the toner carrier. A toner supply member composed of a rotatable cylindrical elastic body and supplying the non-magnetic one-component toner contained in the toner container to the toner carrier; and abutting on the toner carrier via the non-magnetic one-component toner A toner regulating member for regulating the amount of non-magnetic one-component toner on the toner carrier;
When the diameter of the toner carrier is Rd (mm) and the diameter of the toner supply member is Rs (mm), the following relational expression (1) is satisfied;
1 ≦ Rs−Rd ≦ 10 (1)
The non-magnetic one-component toner has toner particles and an external additive containing at least a binder resin, a colorant, and a release agent,
The amount of the external additive to be added is 0.5 to 5.0 parts by mass based on 100 parts by mass of the toner particles;
The external additive includes fine silica powder treated with silicone oil,
The non-magnetic one-component toner has an agglomeration degree of 5 to 30% and an electric resistivity of 1 × 10 ¹⁴ to 1 × 10 ¹⁸ Ωcm in an electric field of 1 × 10 ⁴ V / cm. Forming method. 2. The image forming method according to claim 1, wherein a diameter Rd of the toner carrier and a diameter Rs of the toner supply member satisfy the following relational expression (2).
2 ≦ Rs−Rd ≦ 8 (2) 3. The image forming method according to claim 1, wherein the diameter Rd of the toner carrier and the diameter Rs of the toner supply member satisfy the following relational expression (3).
3 ≦ Rs−Rd ≦ 6 (3) 4. The image forming method according to claim 1, wherein a diameter Rd of the toner carrier and a diameter Rs of the toner supply member satisfy the following expressions (4) and (5), respectively.
10 ≦ Rd ≦ 14 (4)
12 ≦ Rs ≦ 17 (5)   The image forming method according to any one of claims 1 to 4, wherein the amount of the external additive added is from 1.0 to 3.0 parts by mass based on 100 parts by mass of the toner particles.   The amount of the silica fine powder treated with the silicone oil is 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the toner particles. Image forming method. The image forming method according to claim 1, wherein the external additive contains an external additive having a BET specific surface area of 100 m ² / g or less. A charging step of charging the surface of the latent image carrier, a latent image forming step of forming an electrostatic latent image on the surface of the charged latent image carrier, and a non-magnetic one-component toner using the developing means to develop the electrostatic latent image. A developing step of visualizing the toner image to form a toner image, a transfer step of transferring the toner image onto a transfer material with or without an intermediate transfer member, and a fixing step of fixing the toner image on the transfer material. Toner used in an image forming method including:
The developing means includes: a toner container containing a non-magnetic one-component toner; a rotatable cylindrical member provided in contact with the latent image carrier and carrying the non-magnetic one-component toner and transporting the non-magnetic one-component toner to the latent image carrier; A toner carrier; provided on the surface of the toner carrier in contact with the toner carrier on the upstream side in the rotational direction from the contact position between the toner carrier and the latent image carrier, and having a rotation axis parallel to the rotation axis of the toner carrier. A toner supply member composed of a rotatable cylindrical elastic body and supplying the non-magnetic one-component toner contained in the toner container to the toner carrier; and abutting on the toner carrier via the non-magnetic one-component toner A toner regulating member for regulating the amount of non-magnetic one-component toner on the toner carrier;
When the diameter of the toner carrier is Rd (mm) and the diameter of the toner supply member is Rs (mm), the following relational expression (1) is satisfied;
1 ≦ Rs−Rd ≦ 10 (1)
The non-magnetic one-component toner has toner particles and an external additive containing at least a binder resin, a colorant, and a release agent,
The amount of the external additive to be added is 0.5 to 5.0 parts by mass based on 100 parts by mass of the toner particles;
The external additive includes fine silica powder treated with silicone oil,
The non-magnetic one-component toner has a cohesion of 5 to 30% and an electric resistivity of 1 × 10 ¹⁴ to 1 × 10 ¹⁸ Ωcm in an electric field of 1 × 10 ⁴ V / cm. .

Images