JPH11161004A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method capable of preventing a fog, density unevenness and further, the generation of a streak on an image caused by the sticking/fixing of toner on a layer regulating member and obtaining a stable image density by stabilizing the electrifying and carrying of the toner over a long period and also, an image forming method capable of remarkably prolonging the life of the layer regulating member, in an image forming method using a one-component developer. SOLUTION: An electrostatic latent image is formed on an electrostatic latent image carrier 1, the layer regulating member 5 is abutted on a developer carrier 3, to form a thin layer of the one-component developer on the developer carrier 3 and the electrostatic latent image on the carrier 1 is actualized. At this time, the layer regulating member 5 consists of a rigid body and is abutted on the developer carrier 3 with a pressure of 50 to 200 g/cm and the one- component developer is of an electrostatic charge developer constituted to incorporate toner mother grains consisting of at least binding resin and a colorant and inorganic fine grains whose Mohs'hardness is >=8 and average grain size is 0.1 μm-10 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method, and more particularly, to a method for forming an electrostatic latent image on an electrostatic latent image holder and bringing a layer regulating member into contact with the developer carrier to carry the developer. The present invention relates to an image forming method for forming a thin layer of a one-component developer on a body to visualize an electrostatic latent image on the electrostatic latent image holding member.

[0002]

2. Description of the Related Art At present, as a dry developing method in various electrostatic copying systems put into practical use, a two-component developing system using a carrier such as toner and iron powder and a one-component toner developing system using no carrier are known. ing. In the two-component developing method, the toner particles adhere to the carrier surface to deteriorate the developer, and since only the toner is consumed, the concentration ratio of the toner in the developer decreases. Must be kept constant, and therefore, there is a drawback such as an increase in the size of the developing device. On the other hand, the one-component developing system does not have the above-mentioned disadvantages and has advantages such as downsizing of the apparatus, and is therefore becoming the mainstream of the developing system.

[0003] The one-component toner developing system is classified into a magnetic one-component developing system using a magnetic toner and a non-magnetic one-component developing system using a non-magnetic toner. The magnetic one-component developing method uses a developer carrier provided with a magnetic field generating means such as a magnet inside, holds a magnetic toner containing a magnetic substance such as magnetite inside, and develops a thin layer using a layer regulating member. In recent years, many printers have been put to practical use. On the other hand, in the non-magnetic one-component developing method, since the toner has no magnetic force, a toner supply roll or the like is pressed against the developer carrier to supply the toner onto the developer carrier, and the toner is held by the electrostatic force. It is developed by making the layer thinner by the layer regulating member, and has the advantage that it does not contain a colored magnetic substance and can cope with colorization. Further, since no magnet is used for the developer carrying member, the weight is reduced and the cost is reduced. In recent years, it has begun to be used in small full-color printers and the like.

However, there are still many problems to be solved in the one-component developing system. In the two-component development method,
A carrier is used as a means for charging and transporting the toner. The toner and the carrier are sufficiently stirred and mixed in the developing device, and then transported to the developer carrier to be developed. Charging and conveyance can be maintained, and it is easy to cope with a high-speed developing device.
On the other hand, in the one-component developing method, since there is no stable charging and conveying means such as a carrier, charging and conveying failure due to long-time use and high speed are likely to occur. That is, in the one-component developing method, after the toner is transported onto the developer carrying member, the toner is thinned and developed by the layer regulating member.
Since the chance of contact / frictional charging between the toner and a charging member such as a developer carrying member and a layer regulating member is very short, the amount of low-charge or reverse-polarity charged toner tends to increase as compared with the two-component developing method using a carrier. For this reason, the toner is required to have a faster charging speed and an appropriate charging amount.

In order to satisfy this requirement, the linear pressure at which the layer regulating member abuts on the developer carrier has a high linear pressure, and is 50 g / m2.
It is preferable to carry out development by contacting with a linear pressure larger than cm. That is, in the development under a high linear pressure, the contact area of the layer regulating member is widened, the charging time of the toner is kept long by that amount, and the toner can be stably charged, and the stable layer formation can be performed. Is also possible.

However, in this case, since the contact area between the toner and the layer regulating member is large, there is a problem that the toner is fused and fixed to the layer regulating member. This fixation of the toner makes stable charging and layer formation difficult,
White streaks will occur on the formed image. As described above, since toner adhesion to the blade greatly affects toner charging, developability, and abrasion resistance and friction resistance of the toner,
In order to maintain more stable charging and layer formation, it is necessary to design a toner to withstand stress, and there is still a problem in long-term stabilization of toner transportability. In particular, with the recent colorization, from the viewpoint of smoothness and transparency of the fixed image,
Although a binder resin having a low softening point has been used in many cases, it is easily fused to a charging member by heat, and the chargeability and layer formation of the toner are easily hindered.

Further, as a toner to which inorganic fine particles are added as an abrasive, a toner in which abrasive particles are fixed to a contained colorant in order to prevent image flow due to fusion of the toner to a photoreceptor (Japanese Patent Application Laid-Open No. Sho 63) To prevent filming that occurs when the toner remains on the surface of the photoreceptor without being transferred, a toner in which an abrasive is dispersed and supported (Japanese Patent Application Laid-Open No. 9-62016), For the purpose of suppressing filming by wax, a magnetic toner to which an abrasive is added (JP-A-8-82952) and the like have been proposed. However, in recent years, the demand for printers has increased, and the miniaturization, speeding up, and cost reduction of devices have been progressing.
Equipment has been required to have higher reliability and longer life, and increasing the life of each member is also one of the important issues. There was nothing before.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and aims to solve the problems. That is, an object of the present invention is to provide an image forming method using a one-component developer, in which a toner is charged for a long time,
An object of the present invention is to provide an image forming method which stabilizes conveyance, has no fog or density unevenness, and can obtain a stable image density without streaking on an image due to toner adhesion and fixation to a layer regulating member (charging member). Another object of the present invention is to provide an image forming method capable of significantly extending the life of the layer regulating member without simultaneously damaging the layer regulating member.

[0009]

The present inventors have made various studies to solve the above problems, and as a result, formed an electrostatic latent image on the electrostatic latent image holding member and regulated the layer on the developer carrying member. In an image forming apparatus for forming a thin layer of a one-component developer on a developer carrying member by contacting members to visualize an electrostatic latent image on the electrostatic latent image holding member, a Mohs hardness of 8 or more And the average particle size is 0.1
At the same time as using an electrostatic charge developer externally added with inorganic fine particles having a particle size of 10 μm and using a layer regulating member having a certain degree of rigidity, toner adheres and adheres to the layer regulating member even under a high linear pressure. In addition, the inventors have found that damage on the layer regulating member can be suppressed, and have completed the present invention.

That is, according to the present invention, an electrostatic latent image is formed on an electrostatic latent image carrier, and a layer regulating member is brought into contact with the developer carrier to form a thin layer of a one-component developer on the developer carrier. In the image forming method for forming and visualizing an electrostatic latent image on the electrostatic latent image holding member, the layer restricting member is made of a rigid body, and the developer supporting member has the layer restricting member of 50 g. / Cm and a pressure of 200 g / cm or less, wherein the one-component developer is composed of toner base particles comprising at least a binder resin and a colorant and having a Mohs hardness of 8 or more and an average particle size of 0.1.
This is an image forming method which is an electrostatic charge developer containing inorganic fine particles having a diameter of from 10 μm to 10 μm.

In the present invention, by setting the contact pressure of the layer regulating member to the developer carrier to be greater than 50 g / cm, the toner is stably charged and the layer is formed, and the toner tends to adhere to the blade surface. The toner is scraped off by inorganic fine particles externally added to the toner particles, thereby preventing sticking. Further, since the layer regulating member is made of a rigid body, it is not damaged by such polishing. As a result, the toner layer formation and charging on the developer carrier can be stabilized for a long time, and the image forming method of the present invention capable of obtaining a high-quality image without white streaks has been obtained. is there.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

According to the image forming method of the present invention, there is provided a latent image forming step of forming an electrostatic latent image on an electrostatic latent image holding member, and a layer regulating member is brought into contact with the developer holding member to form a single component on the developer holding member. A latent image forming step of forming a thin layer of developer, a developing step of visualizing an electrostatic latent image on the electrostatic latent image holding member, and a transferring step of transferring a toner image on the latent image holding member to a transfer member And a fixing step of thermally fixing the toner image on the transfer member, wherein the layer regulating member is made of a rigid material, and the layer regulating member is larger than 50 g / cm on the developer carrier.
The one-component developer is composed of toner base particles comprising at least a binder resin and a colorant, and having a Mohs hardness of 8 or more and an average particle size of 0.1 μm.
This is an image forming method which is an electrostatic charge developer containing inorganic fine particles having a particle size of 10 to 10 μm.

In the latent image forming step (the step of forming an electrostatic latent image on the electrostatic latent image holding member), a conventionally known method can be applied.
In the latent image forming step, an electrostatic latent image is formed on a latent image carrier such as a photosensitive layer or a dielectric layer by electrophotography or electrostatic recording. As the photosensitive layer of the latent image holding member used in the present invention, a known layer such as an organic or amorphous silicon can be used. Further, the latent image holding member is obtained by a known manufacturing method such as extruding aluminum or an aluminum alloy and then surface-treating the same, and may have a preferable shape such as a cylindrical shape or a belt shape depending on the device.

In the developing step (the step of visualizing the electrostatic latent image on the electrostatic latent image holding member), toner is applied to a layer regulating member on a rotating cylindrical body as a developer carrying member (developing roll). The developing roll is conveyed to the developing nip, and the developing roll and the latent image holding member for holding the electrostatic latent image are contacted or arranged at a certain gap in the developing section, and the developing roll and the latent image holding member are arranged. The electrostatic latent image is developed with the toner while applying a bias between the two. In the case of magnetic one-component development, a rotating cylindrical body having a built-in magnet is used as a developer carrier, and toner having a magnetic body is transported and held by magnetic force. Further, in the case of non-magnetic one-component development, a method of pressing a toner supply roll such as a urethane sponge or the like against the developer carrying member and supplying the toner onto the developer carrying member may be employed.

The developer carrier used in the present invention includes an elastic sleeve in which a conductive agent such as carbon is dispersed in silicon rubber, NBR, EPDM, or the like, a sleeve from which a metal or ceramic such as aluminum or SUS is drawn, and a toner. In order to control the transportability and chargeability of the substrate, a sleeve coated with a surface treatment such as oxidation or metal plating, polishing, or blasting of the substrate surface, or a resin or charge control agent is used. In terms of durability and maintainability, a rigid body is preferable as in the case of the toner layer regulating member.

In the present invention, a layer regulating member made of a rigid body is used. The use of the layer regulating member made of a rigid body makes the layer less likely to be damaged even when it comes into contact with the electrostatic charge developer of the present invention to which an abrasive having a Mohs hardness of 8 or more is externally added. Here, the rigid body means a material that does not exhibit rubber-like elasticity, and examples of the layer-regulating member made of the rigid body include metal blades such as SUS, aluminum plate, and phosphor bronze, and blades obtained by coating these substrates with a resin. Can be used. Examples of the resin for coating include resins such as acrylic resin, phenol resin and urethane resin. Further, a resin in which molybdenum disulfide, melamine, graphite, silicone acrylic, or the like is mixed with those resins may be used as the coating resin. Further, as the layer regulating member made of a rigid body, a blade in which a thin plate or tape of acrylic resin, aluminum, Teflon, vinyl chloride, high-density polyethylene, or the like is adhered to a base such as SUS can be used. Further, a plate-like blade made of polyoxymethylene resin, acrylic resin, glass or the like can be used.

The linear pressure when the layer regulating member contacts the developer carrier is more than 50 g / cm and 200 g / c.
m, and is preferably developed so as to satisfy a linear pressure of more than 70 g / cm and 150 g / cm or less.
Here, the linear pressure between the developing carrier and the layer regulating member is 50 g / c.
If it is less than m, it becomes difficult to impart stable charge to the toner, and if it is more than 200 g / cm, the toner is strongly adhered to the layer regulating member.

In the developing step of the present invention, the outer diameter of the latent image holding member is set to 10 mm to 25 mm from the viewpoint of miniaturization of the apparatus.
mm, preferably in the range of 10 mm to 20 mm, and it is desirable to use a developing unit in which the outer diameter of the developer carrier is in the range of 5 mm to 15 mm, preferably 5 mm to 10 mm.

The image forming method of the present invention comprises a latent image forming step
In addition to the development step, a transfer step, a cleaning step, or a fixing step may be provided as necessary. In the transfer step in the present invention, a known method such as contact-type transfer in which a transfer roller, a transfer belt or the like is pressed against the latent image holding member to transfer a toner image or non-contact type transfer using a corotron is used. In the cleaning step, toner remaining on the latent image holding member without being transferred in the transfer step is removed by a cleaner. As the cleaning means in the present invention,
Known ones such as blade cleaning or roller cleaning can be used. For blade cleaning, a blade made of an elastic rubber such as silicone rubber or urethane rubber is used. Further, the image forming method of the present invention can be applied to a so-called cleanerless system having no cleaning step. In the fixing step, the toner image transferred to the transfer member is fixed by a fixing device. As a fixing unit, a heat fixing system using a heat roll is preferable.

The one-component developer of the present invention is obtained by externally adding inorganic fine particles having a Mohs hardness of 8 or more and an average particle diameter of 0.1 μm to 10 μm to toner base particles comprising at least a binder resin and a colorant. Electrostatic developer.

The inorganic fine particles externally added as an abrasive of the present invention have a Mohs hardness of 8 or more and an average particle size of 0.1 μm to
It is an inorganic fine particle having a size of 10 μm (hereinafter, may be referred to as “abrasive fine particle”). The Mohs hardness of the inorganic fine particles indicates the Mohs hardness of a substance constituting the inorganic fine particles. The Mohs hardness was determined by a qualitative method in which a talc was 1 and a diamond was 15, a standard mineral and a sample were drawn together, and the scratch was soft and the hardness was small. Mohs hardness of the present invention,
Specifically, Fahrenwald Trans. Am. Inst. Mining. Ma
t. Engrs. 112, 88, 1943. If the Mohs hardness is less than 8, the polishing effect of polishing the surface of the layer regulating member of the inorganic fine particles becomes insufficient. The Mohs hardness is preferably 10 or more.

As such inorganic fine particles, inorganic metal oxides, inorganic metal nitrides, inorganic metal carbides, sulfates, or metal carbonates are used. Specific examples are shown below, but the present invention is not limited to these. Cerium oxide,
Oxides such as chromium oxide and aluminum oxide (alumina), nitrides such as boron nitride and silicon nitride, carbides such as silicon carbide, titanium carbide, boron carbide, vanadium carbide and boron carbide, and borides such as tungsten boride. And one or more of these can be used as needed. Also, the crystal shape and the like are not particularly limited. For example, alumina has α, β, γ, δ, η,
There are crystal systems such as θ, κ, χ, and ρ, but any of them can be used. In the present invention,
It is preferable to use cerium oxide or the like having an appropriate polishing effect.

The average particle size of the inorganic fine particles is 0.1 μm to 10 μm.
μm. 0.3 to 5.0 μm is preferred. These abrasive fine particles are large particles as compared with fluidizing agent fine particles or the like externally added to enhance fluidity, and exhibit a polishing effect depending on the size of the material in addition to the hardness of the material. Therefore, if the average particle size is less than 0.1 μm, the polishing action is weak, and the function of scraping off the toner or the external additive adhered and fixed to the layer regulating member is not exhibited. On the other hand, the average particle size is 10 μm
If the ratio exceeds the above, the polishing action becomes too strong, and the developer carrier, the layer regulating member, and the surface of the photoreceptor are damaged.

The inorganic fine particles may be those whose surfaces have been subjected to hydrophobic treatment with a surface treating agent such as a silane coupling agent, silicone oil, a titanium coupling agent, a high molecular fatty acid, or a metal salt thereof. By performing the hydrophobic treatment, the chargeability due to environmental differences is improved. Examples of the titanium coupling agent include tetrabutyl titanate, tetraoctyl titanate, isopropyl isostearyl titanate, isopropyl tridecylbenzenesulfonyl titanate, and bis (dioctyl pyrophosphate) oxyacetate titanate. Further, silane coupling agents include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N−
Vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, hexyltrimethoxysilane,
Octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, p
-Methylphenyltrimethoxysilane and the like.
As the silicone oil, dimethyl silicone oil, methyl hydrogen silicone oil, methyl phenyl silicone oil and the like can be used. Further, if necessary, alkyl modification, amino modification, epoxy modification, carboxy modification, mercapto modification, alcohol modification, fluorine modification and the like may be performed. Examples of fatty acids and metal salts thereof include undecylic acid, myristic acid, lauric acid, undecanoic acid, palmitic acid, pentadecanoic acid, stearic acid, heptadecanoic acid, arachinic acid, montanic acid, oleic acid, linoleic acid, and arachidonic acid. Long-chain fatty acids include, as metal salts of zinc, iron, magnesium,
Salts with metals such as aluminum, calcium, sodium, lithium and the like can be mentioned.

In the one-component developer of the present invention, the amount of the fine abrasive particles added to the toner base particles varies depending on the type of the abrasive and cannot be specified unconditionally. Thus, the amount is preferably 0.2 to 20 parts by weight, more preferably 1.0 to 10 parts by weight. If the amount exceeds 20 parts by weight, the dispersion stability of the toner becomes poor, and the polishing action becomes too strong, which may damage the developer carrier, the layer regulating member, and the surface of the photoreceptor. On the other hand, if the addition amount is less than 0.2 parts by weight, the polishing action is weak, and the function of scraping off the toner or the external additive adhered and fixed to the layer regulating member is not exhibited.

The toner base particles used in the present invention comprise at least a binder resin and a magnetic material in the case of a magnetic toner, and comprise at least a binder resin and a colorant in the case of being used as a non-magnetic toner. Is particularly effective when the toner is a non-magnetic toner containing no magnetic substance. That is, when a magnetic toner is used, the magnetic substance is exposed on the toner surface, and the toner itself has a polishing action of polishing the surface of the layer regulating member to some extent. , For non-magnetic toner,
There is no such a polishing action, and it easily adheres to the layer regulating member.
Further, the non-magnetic toner is more easily charged up and the toner is more easily electrostatically attached to the layer regulating member than the magnetic toner. For this reason, it is considered that the effect of the present invention appears significantly.

As the binder resin constituting the toner base particles of the present invention, polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Known materials such as butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polypropylene, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, and paraffin wax can be used. Preferred are copolymers and polyester resins.

The effect of the present invention is particularly large when a binder resin having a softening point of 90 to 120 ° C. and a low softening point is used. The softening point as used herein means a temperature at a melt viscosity of 10 ⁴ Pa · s (10 ⁵ poise) measured with a flow tester (manufactured by Shimadzu Corporation, nozzle 1 × 1 mm, load 10 kg).

As the colorant constituting the toner base particles of the present invention, conventionally known colorants can be used. As a colorant of such a toner, for example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine,
Malachite Green Oxalate, Lamp Black, Rose Bengal, CI Pigment Red 48: 1, CI Pigment
Red 122, CI Pigment Red 57: 1, CI Pigment Yello
w 97, CI Pigment Yellow 12, CI Pigment Yellow
17, CI Pigment Yellow 180, CI Pigment Blue 15:
1, CI Pigment Blue 15: 3.

As the magnetic material constituting the toner base particles of the present invention, any conventionally known magnetic materials can be used. For example, metals such as iron, cobalt, and nickel and alloys thereof, Fe ₃ O ₄ , γ-Fe
₂ O ₃ , metal oxides such as cobalt-added iron oxide, MnZn
Ferrites such as ferrite and NiZn ferrite are exemplified. These magnetic materials are generally used in an amount of 30 to 70% by weight based on all toner materials.

In the toner base particles used in the present invention, a release agent may be added for the purpose of improving gloss and offset. As the release agent, a paraffin having 8 or more carbon atoms, polyolefin, or the like is preferable, and examples thereof include paraffin wax, paraffin latex, microcrystalline wax, carnauba wax, and the like, or polypropylene, polyethylene, and the like. These may be used alone or in combination. be able to.

Further, in the toner base particles used in the present invention, a charge control agent can be added for the purpose of assisting charging of the toner. As a charge control agent when used as a negatively charged toner, chromium, an azo complex salt dye such as iron, chromium of salicylic acid, zinc, aluminum, a complex compound such as boron, a charge control resin, when used as a positively charged toner,
Known compounds such as quaternary ammonium salts can be used.

In the present invention, in addition to the above-mentioned abrasive fine particles, a fluidizing agent fine particle or a conductive powder is used for the purpose of imparting appropriate fluidity and chargeability to the developer, and for the purpose of improving charge exchangeability. Other fine particles may be externally added. Such fine particles include, for example, inorganic fine powders such as hydrophobic silica and hydrophobically treated fine particles of titanium oxide, organic fine powders such as fatty acids or derivatives thereof and metal salts, fluororesins, acrylic resins and styrene resins. Among them, inorganic fine powder of silica whose surface is hydrophobized with a silane coupling agent or silicone oil is preferred, and silica-treated silica is particularly preferred. These fine particles are used in an amount of 0.1 to 3.0 parts by weight, preferably 0.2 to 3.0 parts by weight, based on the toner base particles.
To 2.0 parts by weight, more preferably 0.3 to 1.5 parts by weight.

The particle diameter of the one-component developer used in the present invention is preferably 4 to 12 μm, more preferably 6 to 10 μm in terms of volume average particle diameter. When the volume average particle size is smaller than 4 μm, the fluidity is remarkably deteriorated, so that a layer cannot be formed well and fog and dart are easily caused. In addition, when the thickness exceeds 12 μm, not only does the resolution decrease and high image quality cannot be obtained, but also
Since the charge amount per unit weight of the developer is reduced, the layer formation retention is poor and fog and dart are easily generated. The particle size of the one-component developer used in the present invention was measured with a particle size analyzer “Coulter Counter TA-II” manufactured by Coulter Electronics Co., Ltd., with an aperture diameter of 100 μm.

The one-component developer used in the present invention can be produced by any known method. For example, kneading and pulverizing method, that is, after pre-mixing the binder resin and the colorant, the charge controlling agent, etc., melt-knead with a kneading machine, cool, pulverize and classify, and add and mix the external additive fine particles, It can be produced by a method for producing a toner or a polymerization method such as suspension polymerization or emulsion polymerization. In particular, the addition and mixing of the external additive fine particles can be performed by, for example, a V-type blender, a Henschel mixer, or a Loedige mixer. Further, if necessary, coarse particles of the toner can be removed using a vibration sieving machine, a wind sieving machine, or the like.

[0037]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 (Preparation of Non-Magnetic One-Component Toner 1) Binder resin: polyester resin composed of terephthalic acid and bisphenol A ethylene oxide adduct (weight average molecular weight Mw: 12000, Tg: 65 ° C., softening point: 100 ° C., specific gravity: 1.1 g / cm ³ ) 92 parts by weight Colorant: copper phthalocyanine blue pigment 5 parts by weight Charge control agent: salicylic acid metal salt (trade name “Bontron E84”, manufactured by Orient Chemical Co.) 3 parts by weight After pre-mixing with a Henschel mixer,
The mixture was kneaded with a twin-screw extruder at a set temperature of 140 ° C., a screw rotation speed of 300 rpm, and a supply speed of 150 kg / h. After cooling, the mixture was roughly pulverized, finely pulverized with a jet mill, and further classified with an air classifier to obtain toner particles having a volume average particle diameter D50 of 9.0 μm. An average particle diameter of 12 n was added to 100 parts by weight of the obtained classified toner particles.
0.8 parts by weight of silica treated with dimethyl silicone oil and 1.0 part by weight of rutile type titanium oxide hydrophobized with decyltrimethoxysilane having an average particle size of 15 nm, and oxidation having a Mohs hardness of 10 and an average particle size of 0.7 μm. Cerium 1.
0 parts by weight were mixed with a Henschel mixer to prepare a non-magnetic one-component toner 1. (Developer Carrier and Latent Image Holder) As the developer carrier, the circumferential surface of an aluminum round bar having a diameter of φ = 15 mm was machined to form irregularities having an average surface roughness Ra of 0.5 μm. The formed one was used. As the latent image holding member, an organic photoreceptor using a base material produced by extrusion molding with an aluminum alloy having an outer diameter of φ = 40 mm and surface processing was used. (Preparation of Layer Control Member 1 and Print Test) 15 g of an acrylic resin (trade name “BR80”, manufactured by Mitsubishi Rayon Co., Ltd.) was mixed with 75 g of methyl ethyl ketone and allowed to stand on a wave rotor for 24 hours to obtain a layer control member coating solution. . This layer regulating member coating liquid is made of stainless steel having a thickness of 0.15 m.
After applying a dip on the m plate spring material, the layer was dried at 110 ° C. for 1 hour to obtain a layer regulating member 1. The thickness of the coat layer on the surface was about 1.0 μm. Developer carrier and layer regulating member 1
To a non-magnetic one-component image forming apparatus shown in FIG.
/ Cm, and print using a non-magnetic one-component toner 1 in a high-temperature and high-humidity environment (28 ° C., 85% RH) and a low-temperature and low-humidity environment (10 ° C., 15% RH) for 10,000 prints each. As a result of the test, sufficient image density, background fog, and high image quality without streaks were continuously obtained in both environments. After the test was completed, the layer regulating member was examined, and no toner adhesion was observed. Table 1 shows the results
Shown in

[0039]

[Table 1]

Example 2 (Preparation of Non-Magnetic One-Component Toner 2) Using the same classified toner particles as in Example 1, 100 parts by weight of the classified toner particles were treated with dimethyl silicone oil having an average particle diameter of 12 nm. 0.8 parts by weight of silica, 1.0 part of rutile-type titanium oxide hydrophobized with decyltrimethoxysilane having an average particle diameter of 15 nm, and an average particle diameter of 5.0 at Mohs hardness of 10.
0.2 part by weight of cerium oxide of μm was mixed with a Henschel mixer to prepare a non-magnetic one-component toner 2. (Print test) The layer regulating member 1 was attached to the same image forming apparatus as in Example 1 at a linear pressure of 70 g / cm, and the same print test as in Example 1 was performed using the non-magnetic one-component toner 2. In both environments, sufficient image density, background fog, and high image quality without streaks on the image were continuously obtained. After the test was completed, the layer regulating member was examined, and no toner adhesion was found. Table 1 shows the results.

Example 3 (Preparation of non-magnetic one-component toner 3) The same classified toner particles as in Example 1 were used, and 100 parts by weight of the classified toner particles were treated with dimethyl silicone oil having an average particle diameter of 12 nm. 0.8 parts by weight of silica, 1.0 part of rutile type titanium oxide hydrophobized with decyltrimethoxysilane having an average particle diameter of 15 nm, and an average particle diameter of 0.5 at Mohs hardness of 12.
0.5 μm of boron nitride having a thickness of μm was mixed with a Henschel mixer to prepare a non-magnetic one-component toner 3. (Print test) The layer regulating member 1 was attached to the same image forming apparatus as in Example 1 at a linear pressure of 70 g / cm, and the same print test as in Example 1 was performed using the non-magnetic one-component toner 3. In both environments, sufficient image density, background fog, and high image quality without streaks on the image were continuously obtained. After the test was completed, the layer regulating member was examined, and no toner adhesion was found. Table 1 shows the results.

Example 4 (Preparation of Non-Magnetic One-Component Toner 4) Using the same classified toner particles as in Example 1, 100 parts by weight of the classified toner particles were treated with dimethyl silicone oil having an average particle diameter of 12 nm. 0.8 parts by weight of silica, 1.0 part of rutile type titanium oxide hydrophobized with decyltrimethoxysilane having an average particle size of 15 nm, and an average particle size of 0.5 at Mohs hardness of 10.
0.5 part by weight of cerium oxide of 0.5 μm was mixed with a Henschel mixer to prepare a non-magnetic one-component toner 4. (Print test) The layer regulating member 1 was attached to a developing unit having an outer diameter of a latent image holder of 10 mm and an outer diameter of a developing carrier of 10 mm at a linear pressure of 70 g / cm, and a non-magnetic one-component toner 4 was used. When a print test similar to that in Example 1 was performed, sufficient image density, background fog, and high image quality without streaks were continuously obtained in both environments. After the test was completed, the layer regulating member was examined, and no toner adhesion was found. Table 1 shows the results.

Comparative Example 1 (Preparation of Non-Magnetic One-Component Toner 5) Using the same classified toner particles as in Example 1, 100 parts by weight of the classified toner particles were treated with dimethyl silicone oil having an average particle diameter of 12 nm. 0.8 part by weight of silica and 1.0 part of rutile-type titanium oxide hydrophobized with decyltrimethoxysilane having an average particle diameter of 15 nm were mixed with a Henschel mixer to prepare a non-magnetic one-component toner 5. (Print test) The layer regulating member 1 was attached to the same image forming apparatus as in Example 1 at a linear pressure of 70 g / cm, and the same print test as in Example 1 was performed using the non-magnetic one-component toner 5. Streaks were formed on the image at about 2000 sheets in a high-temperature and high-humidity environment and more than 1000 sheets in a low-temperature and low-humidity environment, and the image density was reduced and the background fogging gradually deteriorated. After the test, the layer regulating member was examined. As a result, a large amount of toner adhered to the Nip portion in contact with the sleeve. Table 1 shows the results.

Comparative Example 2 (Preparation of Non-Magnetic One-Component Toner 6) The same classified toner particles as in Example 1 were used, and 100 parts by weight of the classified toner particles were treated with dimethyl silicone oil having an average particle diameter of 12 nm. 0.8 parts by weight of silica, 1.0 part of rutile-type titanium oxide hydrophobized with decyltrimethoxysilane having an average particle size of 15 nm, and a Mohs hardness of 1 to 2 and an average particle size of 0.
0.5 part by weight of 5 μm molybdenum disulfide was mixed with a Henschel mixer to prepare a non-magnetic one-component toner 6. (Print Test) The layer regulating member 1 was attached to the same image forming apparatus as in Example 1 at a linear pressure of 70 g / cm, and the same print test as in Example 1 was performed using the non-magnetic one-component toner 6. Streaks were formed on the image at about 2000 sheets in a high-temperature and high-humidity environment and more than 1000 sheets in a low-temperature and low-humidity environment, and the image density was reduced and the background fogging gradually deteriorated. After the test, the layer regulating member was examined. As a result, a large amount of toner adhered to the Nip portion in contact with the sleeve. Table 1 shows the results.

Comparative Example 3 (Preparation of Non-Magnetic One-Component Toner 7) The same classified toner particles as in Example 1 were used, and 100 parts by weight of the classified toner particles were treated with dimethyl silicone oil having an average particle diameter of 12 nm. 0.8 parts by weight of silica, 1.0 part of rutile-type titanium oxide hydrophobized with decyltrimethoxysilane having an average particle diameter of 15 nm, and an average particle diameter of 5.0 at Mohs hardness of 10.
A non-magnetic one-component toner 7 was prepared by mixing 2.5 parts by weight of cerium oxide of μm with a Henschel mixer. (Production of layer regulating member 3 and print test) 0.15 mm
A 1 mm-thick urethane rubber was stuck on a SUS substrate having a thickness of 3 mm to obtain a layer regulating member 3. The layer regulating member 3 was attached to the same image forming apparatus as in Example 1 at a linear pressure of 70 g / cm, and the same print test as in Example 1 was performed using the non-magnetic one-component toner 7. 2000 under the environment
When the number of sheets exceeded 1,000 in a low-temperature and low-humidity environment, the image density decreased and the background fog occurred, and the quality gradually deteriorated. After completion of the test, the developer carrier, the layer regulating member, and the latent image holder were examined. As a result, scratches were confirmed on the surface.
Table 1 shows the results.

(Non-Magnetic One-Component Image Forming Apparatus) FIG. 1 shows an image forming apparatus used for evaluating the image quality of Examples 1-4 and Comparative Examples 1-2. The developing machine having the non-magnetic toner includes an aluminum developer carrier 3 having a surface sand-blasted to an average surface roughness Ra of 0.5 μm, and a developer supply roller 4 in which carbon black is dispersed in an acrylic resin. You. The developer carrier 3 was placed in non-contact with the latent image carrier 1 with a gap of 0.2 mm. The latent image holder 1 is charged by a roller charger 2 and then exposed to laser light to form an electrostatic latent image. The developer carrier 3, developer supply roller 4, developer layer regulating member 5 Was applied with an AC voltage having a Vpp of 2.0 kV and a frequency of 2.0 kHz and a DC voltage of -300 V to develop an electrostatic latent image. The toner layer was formed on the developer carrying member by bringing the developer layer regulating member 5 into contact with the developer carrying member 3 at a constant linear pressure. The peripheral speed of the latent image holder 1 is 80 mm / s, and the peripheral speed of the developer carrier 3 is 11 mm / s.
0 mm / s, and the transfer of toner is performed using a transfer roller.
For cleaning, a blade-type cleaner was used. For fixing, a heat roller fixing device was used.

(Image Quality Evaluation Method) <Image Density> A density measuring device manufactured by X-rite, X-ri
Measured by te404A. <Fogging on print> The background portion was observed with a 50x loupe and evaluated organoleptically. None, slightly, and fairly good were evaluated as ○, Δ, and ×, respectively. <White streaks on the image> The number of streaks generated in an image obtained by developing the entire surface of the toner on A4 paper was evaluated as ○ for 5 or less, Δ for 6 to 10 and × for 11 or more.

It can be seen from Examples 1 to 4 that if the image forming method of the present invention is used, sufficient image density and image density can be obtained not only in a high-temperature and high-humidity environment but also in a low-temperature and low-humidity environment where toner is likely to adhere due to high charge. It can be seen that high image quality without background fog and no streaks on the image can be maintained up to 10,000 sheets. That is, it is understood that high image quality can be obtained continuously over a long period of time. In addition, it can be seen that the layer regulating member is not damaged by the abrasive, and the life of the layer regulating member is significantly extended. On the other hand, when the abrasive is not externally added to the developer, streaks appear on the image from around 2,000 sheets in a high-temperature and high-humidity environment, and over 1,000 sheets in a low-temperature and low-humidity environment, and the image density decreases. It can be seen that the background portion is fogged (Comparative Example 1). Also,
When fine particles with low Mohs hardness are externally added to the developer,
2000 sheets under high temperature and high humidity environment, 1000 sheets under low temperature and low humidity environment
It can be seen that streaks are formed on the image from around the end of the sheet, and that the image density is reduced and the background is fogged (Comparative Example 2). When an elastic body is used for the layer regulating member, in an environment of high temperature and high humidity, 2000 sheets, and in an environment of low temperature and low humidity,
It can be seen that streaks are formed on the image and scratches are generated on the surface of the layer regulating member from around 1000 sheets (Comparative Example 3).

According to the image forming method of the present invention, the toner is hard to adhere to the layer regulating member, so that the charging of the toner and the formation of the layer are stable, and the environment of charging is less dependent on the environment. High image density, low developability, background fog,
It is possible to obtain excellent image quality that does not cause a problem such as generation of white streaks on an image. Further, the layer regulating member is not damaged by the abrasive, and the layer regulating member can be continuously used for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus having a developer layer regulating member of the present invention.

[Description of Signs] 1 Latent image holder 2 Roller charger 3 Developer carrier 4 Developer supply roller 5 Developer layer regulating member 6 Transfer roller 7 Cleaner 8 Fixer

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kotaro Yoshihara Fuji Xerox Co., Ltd., 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture

Claims (8)

[Claims] An electrostatic latent image is formed on an electrostatic latent image holding member, and a layer regulating member is brought into contact with the developer holding member to form a thin layer of a one-component developer on the developer holding member. In the image forming method for visualizing an electrostatic latent image on the electrostatic latent image holding member, the layer regulating member is made of a rigid body, and the layer regulating member is larger than 50 g / cm on the developer carrier. 200g
The one-component developer is composed of at least a toner base particle composed of a binder resin and a colorant, and an inorganic particle having a Mohs hardness of 8 or more and an average particle diameter of 0.1 μm to 10 μm. An image forming method, which is an electrostatic charge developer containing fine particles. 2. The image forming method according to claim 1, wherein the toner base particles are a non-magnetic one-component toner. 3. The image forming method according to claim 1, wherein the content of the inorganic fine particles is 0.2% by weight to 20% by weight based on the toner base particles. 4. The softening point of the binder resin is 90.degree.
The image forming method according to claim 1, wherein the temperature is 0 ° C. 5. 5. The electrostatic latent image holding member has an outer diameter of 10 mm.
The image forming method according to any one of claims 1 to 4, wherein the thickness is from 25 mm to 25 mm. 6. The developer carrier having an outer diameter of 5 mm to 15 mm.
The image forming method according to any one of claims 1 to 5, wherein the distance is in mm. 7. The one-component developer according to claim 1, further comprising inorganic fine particles having an average particle size of 5 nm to 50 nm.
7. The image forming method according to any one of items 1 to 6. 8. The image forming method according to claim 1, wherein the developer carrier is selected from the group consisting of a metal, a ceramic, and a plastic.