JPH10177303A - Developing sleeve and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize electrification and carrying of a toner for a long time, to maintain electrification property under high temp. and high humidity conditions or low temp. and low humidity conditions, and to avoid irregular density and ghost images by forming a coating layer containing a phenol resin having nitrogen atoms. SOLUTION: A developing sleeve having a coating layer containing at least a phenol resin having nitrogen atoms is used. The base body of the developing sleeve is a cylinder of metal or a ceramic material such as aluminum, SUS produced by drawing. The surface of the body may be subjected to surface treatment such as polishing and blasting in order to control the carrying amt. of a toner or to improve adhesion property with a phenol resin. The phenol resin having nitrogen atoms is a phenol resin having covalent bonds of carbon and nitrogen in the phenol ring of the resin. The developing sleeve is produced by applying a phenol resin to form a coating layer on the base body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing sleeve used for dry development in electrophotography or electrostatic recording, and an image forming method using the same.

[0002]

2. Description of the Related Art Dry developing methods in various electrophotographic or electrostatic recording methods that are currently in practical use include a two-component developing method using a carrier such as toner and iron powder and a one-component developing method using no carrier. The scheme is known. 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. However, the one-component developing method does not have the above-mentioned drawbacks and has the advantage that the apparatus can be downsized. It is becoming.

[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 is a method in which a magnetic toner having a magnetic substance such as magnetite is held on the surface of a developing sleeve provided with a magnetic field generating means such as a magnet inside, and the layer is thinned by a layer regulating member and developed. In recent years, a large number of 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 developing sleeve, the toner is supplied onto the developing sleeve, and the toner is held on the developing sleeve surface by electrostatic force. It is developed by thinning the layer with the layer regulating member, and has the advantage that it does not have a colored magnetic material and can respond to colorization.In addition, since a magnet is not used for the developing sleeve, it is possible to reduce the weight and cost, and in recent years It has begun to be used in small full-color printers.

In the two-component developing 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 developing sleeve to be developed. It is possible to maintain stable charging and conveyance even when used for an extremely long time, and it is easy to cope with a high-speed developing device. However, in the one-component developing method, since there is no stable charging and transporting means such as a carrier, charging and transporting defects are likely to occur due to long-time use or high speed, and there are still many problems to be solved. In other words, in the one-component developing method, after the toner is conveyed to the surface of the developing sleeve, the toner is thinned and developed by the layer regulating member. However, the contact and friction between the toner and the charging member such as the developing sleeve and the layer regulating member are performed. Since the charging opportunity is very short, a low-charge or reverse-polarity toner is more likely to be generated as compared with the two-component developing method using a carrier, and the toner is required to have a quicker charging speed and an appropriate charging amount. In the one-component developing method, toner deterioration due to repeated use,
Contamination of the charging member by toner or external additives may cause toner charging,
Since it greatly affects layer formation and developability, in order to maintain stable charging and layer formation for a long period of time, it is necessary not only to improve the toner but also to design a charging in consideration of both the toner and the charging member.

Conventionally, as a developing sleeve, a metal sleeve such as aluminum or stainless steel (SUS) or an elastic sleeve such as silicone rubber, NBR or EPDM has been used. However, since these developing sleeves themselves have low charging ability, it is not only difficult to adjust the initial charge of the toner, but also due to the deterioration of the toner due to long-term use and the contamination of the charging member, the low-charged toner and the opposite-polarity toner may be removed together with the number of copies. However, problems such as fogging and a decrease in image density were likely to occur.

[0006] In order to improve these problems, many attempts have been made to increase the initial charge of the toner, for example, by coating the surface of the developing sleeve with a charge control material having a chargeability opposite to that of the toner. A method of coating the developing sleeve with a resin such as an acrylic resin or a nylon resin exhibiting a positive charge to assist the chargeability of the negatively charged toner, or the resin or other non-chargeable resin such as a phenol resin For example, a method has been attempted in which a positive charge control agent such as a quaternary ammonium salt is contained to coat the developing sleeve. In particular, phenol resin is a preferable material for coating the developing sleeve because it has high mechanical strength, abrasion resistance, and excellent durability.

[0007] However, these developing sleeves have an effect of increasing the charge amount by assisting the charging speed of the toner in the initial stage, but all of them have poor environmental stability. Excessive charging in the vicinity causes two-layered charging, which tends to cause problems such as a reduction in image density and ghosts. Further, in the method of coating a developing sleeve with a positive charge control agent contained in a phenol resin, even if the phenol resin alone has high environmental stability, the durability and environmental stability are not sufficient in the end.

Japanese Patent Application Laid-Open No. 62-306,287 proposes an attempt to coat a silicone resin containing an aminosilane coupling agent on the surface of a developing sleeve.
As described above, an attempt to include a resin having a functional group containing nitrogen such as an amino group on the surface of the developing sleeve certainly has an effect of increasing the charge, but the charge amount decreases under a very long use, and There are still challenges to obtain stable image quality.

[0009]

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 stabilize toner charging and conveyance for a long time in a one-component developing system,
Further, the present invention provides a developing sleeve and an image forming method capable of maintaining an appropriate charge amount even under high temperature and high humidity and low temperature and low humidity, and obtaining a high density, stable image without density unevenness and ghost. It is in.

[0010]

The above object is achieved by the present invention described below. That is, the present invention provides a developing sleeve provided with a coating layer containing at least a phenol resin having a nitrogen atom, and an image forming method using the same.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The developing sleeve of the present invention includes a latent image forming step of forming an electrostatic latent image on an electrostatic latent image holding member (hereinafter, simply referred to as a “latent image holding member”), and a developing process in which a thin layer is formed on the developing sleeve. Developing a latent image on the latent image holding member using an agent, a transfer step of transferring a toner image on the latent image holding member onto a transfer member,
In the image forming method having a fixing step of fixing the toner image on the transfer body by heat or the like, it is used as a developing sleeve.

In the latent image forming step, a conventionally known method can be applied, and an electrostatic latent image is formed on a cylindrical latent image holding member such as a photosensitive layer or a dielectric layer by an electrophotographic method or an electrostatic recording method. Form. 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. The cylindrical latent image holding member can be obtained by a known manufacturing method such as extruding aluminum or an aluminum alloy, followed by surface processing.

The developing step includes a developing sleeve (developing roll).
A thin layer of toner is formed on a rotating cylindrical body by a layer regulating member, and is conveyed to a developing nip. A developing sleeve and a latent image holding body for holding an electrostatic latent image are brought into contact with the developing unit or at a certain gap. The electrostatic latent image is developed with toner while applying a bias between the developing sleeve and the latent image holding member. In the case of magnetic one-component development, a rotating cylinder body having a magnet built therein is used as a developing sleeve, and a toner having a magnetic material inside is held and conveyed by a magnetic force. 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 developing sleeve and supplying the toner onto the developing sleeve may be employed. In the present invention, the regulation of the toner layer is performed by bringing an elastic blade such as silicone rubber or urethane rubber or a metal blade such as SUS or phosphor bronze into contact with the surface of the developing sleeve.

As the base of the developing sleeve of the present invention, a cylindrical body from which a metal such as aluminum or SUS or ceramics is drawn is used. The surface of the substrate may be subjected to a surface treatment such as polishing or blasting for the purpose of controlling the amount of toner transported or improving the adhesion to the phenol resin.

The coating layer of the developing sleeve in the present invention needs to contain a phenol resin having at least a nitrogen atom. The phenolic resin having a nitrogen atom in the present invention, the phenol nucleus in the resin,

[0016]

Embedded image

A phenolic resin having a covalent bond between carbon and nitrogen, such as an ammonia resol. For example, when a phenol is reacted with an aldehyde in the production of a phenolic resin, a nitrogen-containing compound such as ammonia or an amine is used as a catalyst. Resin resin with nitrogen incorporated in its main chain, aniline-modified, secondary diallylmonoamine-modified, primary monoallylamine-modified, melamine-modified, urea-modified, etc. co-condensation resin of phenolic resin and nitrogen-containing compound Is mentioned. Specific examples of these phenol resins include PS2105 and PS610 manufactured by Gunei Chemical Industry Co., Ltd.
8 and PS6110 (all are trade names).
The phenolic resin having a nitrogen atom in the present invention can impart strong negative chargeability to the toner by the nitrogen atom contained therein, and is excellent in environmental stability, particularly humidity stability. Compared with conventional negatively charged materials such as ordinary phenolic resin (containing no nitrogen atom) containing a control agent, it does not become excessively charged under low temperature and low humidity, and is used for toner even under high temperature and high humidity environment. A sufficient amount of charge can be provided, and the mechanical strength is high without impairing the characteristics of the phenol resin, and the durability is high.

The developing sleeve of the present invention is formed by coating the above-mentioned phenol resin on the above-mentioned substrate to form a coating layer. When coating with a phenolic resin, the above-mentioned phenolic resin having a nitrogen atom may be coated alone, but mixed with a normal phenolic resin having no nitrogen atom and / or other general resins for the purpose of charge control or the like. You may use it. As other general resins that can be used in combination, those that are compatible with the phenol resin and do not extremely inhibit the chargeability of the coating layer are preferable, and examples thereof include an acrylic resin, a polyamide resin, and a melamine resin. However, if the ratio of the phenol resin having a nitrogen atom is reduced, the effect of the present invention is diluted,
The mixing ratio of the phenol resin having a nitrogen atom and other general resins (including ordinary phenol resins) that can be used in combination is preferably in the range of 0 to 80% by weight.

For the purpose of imparting conductivity, powder of inorganic fine particles such as carbon black, magnetic powder, and tin oxide can be added to the coating layer. Further, a powder such as a graphite or a solid lubricant such as molybdenum disulfide capable of imparting lubricity to the surface of the developing sleeve may be added to the coating layer. In particular, molybdenum disulfide is preferable because it imparts lubricity to the coating layer of the developing sleeve and has resistance controllability. The amount of addition of these powders is 1 to 5 in the coating layer.
It is preferably in the range of 0% by weight. If the amount is too small, the effect of adding the powder cannot be obtained, and if the amount is too large, the chargeability of the coating layer is undesirably affected. The volume average particle size of these powders is 0.1
About 5 μm is preferable. If the particle size is too large, poor dispersion in the resin tends to occur, and if the particle size is too small, the effect of the addition is hardly obtained.

Further, a low surface energy material such as a wax or a fluororesin can be added to the coating layer for the purpose of preventing adhesion and improving slipperiness. These materials need to be added within a range that does not significantly affect the charge imparting property and environmental stability of the developing sleeve of the present invention, and are preferably in the range of 0.1 to 10% by weight in the coating layer.

[0021] The thickness of the coating layer is preferably in the range of 1 to 30 µm, more preferably 5 to 20 µm, and particularly preferably 10 to 20 µm. If the thickness of the coating layer is less than 1 μm, there is a problem in durability, and if it exceeds 30 μm, it becomes difficult to coat, and the developability tends to deteriorate.

The method for manufacturing the developing sleeve of the present invention is as follows. A material such as a solid lubricant is dispersed in a solution in which a resin for forming a coating layer is dissolved in a solvent in advance, and then, dipping and spray coating are performed. For example, there is a method of applying to the substrate surface by a known method and drying or curing by applying heat as needed. As the solvent to be used, any solvent can be used as long as it can dissolve the resin forming the coating layer, and examples thereof include ketone solvents such as methyl ethyl ketone, and alcohol solvents such as methanol and ethanol. Can be

In the transfer step in the present invention, a known method such as a contact type transfer in which a transfer roller or the like is pressed against a latent image holding member to transfer a toner image or a non-contact type using a corotron is used. In the cleaning step of the present invention, the toner remaining on the surface of the latent image holding member without being transferred in the transfer step is removed by a cleaning unit. The cleaning means in the present invention includes known means such as blade cleaning or roller cleaning. Elastic rubber such as silicone rubber or urethane rubber is used for blade cleaning. In the fixing step, the toner image transferred to the transfer body is fixed by a fixing device. As a fixing unit, a heat fixing system using a heat roll is preferable.

When used as a non-magnetic toner, the toner used in the present invention comprises at least a binder resin and a colorant. Examples of the binder resin of the toner used in the present invention include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, and styrene-maleic anhydride. Known materials such as an acid copolymer, polyethylene, polypropylene, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, and paraffin wax can be used.

As the colorant of the toner used in the present invention,
Carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, ポ ン upon oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, lamp black, rose bengal, C.I. I. Pi
gment Red 48: 1, C.I. I. Pigmen
t Red 122, C.I. I. Pigment Red
57: 1, C.I. I. Pigment Yellow
97, C.I. I. Pigment Yellow 12,
C. I. Pigment Yellow 17, C.I.
I. Pigment Blue 15: 1, C.I. I. P
Pigment Blue 15: 3.

In the present invention, a magnetic substance may be further contained in the toner to be used as a magnetic toner. As the magnetic material that can be used in the present invention, any conventionally known magnetic materials can be used. For example, iron, cobalt, and alloys such as _{nickel, Fe 3 O 4, γ-} Fe 2 O 3, metal oxides such as cobalt added iron oxide, MnZn ferrite, Ni
Ferrites such as Zn ferrite are exemplified. These magnetic materials generally comprise 30 to 70% by weight of the entire toner.
Used in addition. The developing sleeve of the present invention is suitable even when a magnetic toner is used because of its excellent environmental stability and durability.

Further, in the toner used in the present invention,
A release agent may be added for the purpose of improving gross and offset properties. The release agent is preferably a paraffin having 8 or more carbon atoms, polyolefin, or the like. Examples thereof include paraffin wax, paraffin latex, microcrystalline wax, and the like, and polypropylene, polyethylene, and the like. These may be used alone or in combination.

In the toner used in the present invention, a charge controlling agent may be added for the purpose of assisting the charging of the toner. Known charge control agents such as azo complex dyes such as chromium and iron, complex compounds such as chromium, zinc, aluminum and boron of salicylic acid and charge control resins can be used. The addition amount of these charge control agents is preferably in the range of 0.1 to 5% by weight based on the toner.

In the present invention, a fluidizing agent fine particle is externally used for the purpose of imparting appropriate fluidity and chargeability to the toner. Examples of the fluidizing agent fine particles used include hydrophobic silica, fine particle titanium oxide, inorganic fine powders such as alumina, organic fine powders such as fatty acids or derivatives thereof and metal salts, fluorine-based resins, acrylic resins and styrene-based resins. Resin fine powder and the like can be mentioned, and these can be used alone or in combination.

The particle diameter of the toner used in the present invention is preferably 4 to 12 μm in terms of volume average particle diameter, more preferably 6 to 1 μm.
0 μm is good. When the volume average particle size is less than 4 μm, the fluidity is remarkably deteriorated, so that a layer cannot be formed well, which is likely to cause fogging and dirt. On the other hand, when the thickness exceeds 12 μm, not only the resolution is lowered and high image quality is not obtained, but also the charge amount per unit weight of the developer is lowered, so that the layer formation maintenance is poor and fog and dirt are easily generated.

The toner used in the present invention can be manufactured by any known method. For example, kneading, pulverization method, that is, after pre-mixing the binder resin and the colorant, the charge control agent, and the like,
A method of melt-kneading with a kneader, followed by pulverization and classification after cooling, and addition and mixing of external additive fine particles, or a polymerized toner by suspension polymerization, emulsion polymerization or the like is used.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. (Non-magnetic one-component image forming apparatus) In the present invention, a laser printer Laser Win manufactured by Fuji Xerox Co., Ltd.
d1040 modified to a non-magnetic developing system was used. FIG. 1 is a schematic sectional view of the image forming apparatus used for evaluation. The developing step includes a developing sleeve 3 and a developer supply roller 4 made of urethane sponge. The developing sleeve 3 was disposed so as to have a gap of 0.2 mm from the latent image holding member 1. The latent image holding member 1 is charged by a roller charger 2 and then exposed to laser light to form an electrostatic latent image. A DC voltage is applied to the developing sleeve 3 and the developer supply roller 4 to apply the electrostatic latent image to the electrostatic latent image. Was developed. The toner layer was formed on the developing sleeve by bringing the layer forming blade 5 into contact with the developing sleeve 3 at a constant linear pressure. The latent image holding member 1 has 8
At a peripheral speed of 0 mm / s, the developing sleeve 3 is rotated clockwise by 120 mm / s.
The toner image developed on the latent image holder is rotated counterclockwise at a peripheral speed of mm / s 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> X-ri, a density measuring device manufactured by X-rite
Measured by te404A. <Fogging on print> The background portion was observed with a magnifier of 50 times and the sensitivity was evaluated. The evaluation criteria are as follows. 〇: No fog at all △: Slight fog but no problem in practical use ×: Level with considerable fog and impractical <Fog on photoreceptor> After developing electrostatic latent image and before transferring toner Then, the background portion on the latent image holding member was transferred to a transparent tape, the density was measured by X-rite 404A, and the value was evaluated. <Ghost> The afterimage state in the halftone image after the solid image was sensitized and evaluated. The evaluation criteria are as follows. 〇: No ghost at all △: Slight ghost but no practical problem ×: Ghost is considerable and practically impossible

(Preparation of Developing Sleeve) <Preparation of Developing Sleeve (1) (Invention)> Phenol 5
00 g, 40 g of 40% formalin and 80 g of 25% aqueous ammonia in a reaction vessel were reacted with 10 parts by weight of an ammonia resole resin A, and phenol 500
g, 40 g of 40% formalin and 50 g of a 50% aqueous sodium hydroxide solution in a reaction vessel, and 10 parts by weight of a normal phenol resin containing no nitrogen atom,
After dissolving in a mixed solvent of methyl ethyl ketone 50 ml,
Molybdenum disulfide powder (volume average particle size 0.4 μm) 1
0 parts by weight were added and ultrasonically dispersed to obtain a developing sleeve coating solution (1). The coating solution (1) was coated on the surface of the aluminum sleeve base by a push-up coater so as to have a film thickness of 15 μm, and then dried and cured at 120 ° C. for 1 hour to obtain a developing sleeve (1).

<Preparation of Developing Sleeve (2) (Invention)>
After reacting 500 g of phenol and 400 g of 40% formalin in a reaction vessel, aniline-modified phenol resin B obtained by adding 200 g of aniline: 20 parts by weight was dissolved in a mixed solvent of 50 ml of methyl ethyl ketone, and then molybdenum disulfide was obtained. Powder (volume average particle size 0.4μ
m) 10 parts by weight of the solution were added and ultrasonically dispersed to obtain a developing sleeve coating solution (2). The coating solution (2) was coated on the surface of the aluminum sleeve substrate by a push-up coater so as to have a film thickness of 15 μm, and then dried and cured at 120 ° C. for 1 hour to obtain a developing sleeve (2).

<Preparation of Developing Sleeve (3) (Comparative Example)>
Phenol 500g, 40% formalin 400g and 5
After dissolving 20 parts by weight of a normal phenol resin having no nitrogen atom obtained by reacting 50 g of a 0% aqueous sodium hydroxide solution in a reaction vessel in a mixed solvent of 50 ml of methyl ethyl ketone, a powder of molybdenum disulfide ( 10 parts by weight (volume average particle size: 0.4 μm) was added thereto, and an ultrasonically dispersed solution (3) for developing sleeve coating was obtained. This coating solution (3) was coated on the surface of the aluminum sleeve base by a push-up coater so as to have a thickness of 15 μm,
After drying and curing at 1 ° C. for 1 hour, a developing sleeve (3) was obtained.

(Preparation of Toner) <Preparation of Nonmagnetic One-Component Toner (1)> Binder resin: styrene / n-butyl acrylate (85:15) copolymer resin (Mw 250,000, Tg 60 ° C.) 85 Parts by weight ・ Coloring agent: 5 parts by weight of carbon black BPL (manufactured by Cabot) ・ Charge controlling agent: 5 parts by weight of iron azo complex dye ・ Release agent: 5 parts by weight of polypropylene wax The above materials are premixed with a Henschel mixer. After doing
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 9.3 μm. Further, 0.8 part by weight of silica treated with silicone oil having an average particle size of 12 nm and 100
0.8 nm by weight of 0 nm titanium oxide was mixed with a Henschel mixer to prepare a non-magnetic one-component toner (1).

<Preparation of Nonmagnetic One-Component Toner (2)> Binder resin: styrene / n-butyl acrylate (85:15) copolymer resin (Mw 250,000, Tg 60 ° C.) 90 parts by weight Colorant: 5 parts by weight of carbon black BPL (manufactured by Cabot Corp.)-Release agent: 5 parts by weight of polypropylene wax After premixing the above materials 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 9.2 μm. Further, 0.5 part by weight of silica treated with silicone oil having an average particle diameter of 12 nm and an average particle diameter of 2
0.8 nm by weight of 0 nm titanium oxide was mixed with a Henschel mixer to prepare a non-magnetic one-component toner (1).

Example 1 The developing sleeve (1) was incorporated into the image forming apparatus of FIG. 1 as the developing sleeve 3, and the non-magnetic one-component toner (1) was used in a high-temperature, high-humidity environment (28 ° C., 85 % R
H) and in a low-temperature, low-humidity environment (10 ° C., 15% RH), a 5,000-sheet print test was performed. As a result, a high-quality image without density reduction and fog was continuously obtained until the end. Further, fog on the photoreceptor was confirmed to be good. Table 1 shows the results.

Example 2 The above-mentioned developing sleeve (1) was incorporated into the image forming apparatus of FIG. 1 as a developing sleeve 3, and a print test similar to that of Example 1 was performed using the above-mentioned non-magnetic one-component toner (2). As a result, a high-quality image without density reduction and fog was continuously obtained until the end. Further, fog on the photoreceptor was confirmed to be good. Table 1 shows the results.

Example 3 The above-mentioned developing sleeve (2) was incorporated into the image forming apparatus of FIG. 1 as the developing sleeve 3, and a print test similar to that of Example 1 was performed using the above-mentioned non-magnetic one-component toner (1). As a result, a high-quality image without density reduction and fog was continuously obtained until the end. Further, fog on the photoreceptor was confirmed to be good. Table 1 shows the results.

Example 4 The above-mentioned developing sleeve (2) was incorporated into the image forming apparatus of FIG. 1 as a developing sleeve 3, and a print test similar to that of Example 1 was performed using the above-mentioned non-magnetic one-component toner (2). As a result, a high-quality image without density reduction and fog was continuously obtained until the end. Further, fog on the photoreceptor was confirmed to be good. Table 1 shows the results.

COMPARATIVE EXAMPLE 1 An aluminum sleeve having no coating layer on its surface was incorporated as a developing sleeve 3 in the image forming apparatus shown in FIG. 1, and the same method as in Example 1 was carried out using the non-magnetic one-component toner (1). When a print test was performed, the evaluation under high temperature and high humidity was good, but the evaluation under low temperature and low humidity deteriorated both density reduction, fog and ghost. Table 1 shows the results
Shown in

COMPARATIVE EXAMPLE 2 An aluminum sleeve having no coating layer on its surface was incorporated as a developing sleeve 3 in the image forming apparatus shown in FIG. 1, and the same method as in Example 1 was carried out using the non-magnetic one-component toner (2). When a print test was performed, the density was significantly reduced, and both fog and ghost were poor. Table 1 shows the results.

Comparative Example 3 The above-mentioned developing sleeve (3) was incorporated into the image forming apparatus of FIG. 1 as the developing sleeve 3, and a print test similar to that of Example 1 was performed using the above-mentioned non-magnetic one-component toner (1). As a result, although the evaluation under high temperature and high humidity was good, in the evaluation under low temperature and low humidity, both the decrease in density, fog, and ghost deteriorated. Table 1 shows the results.

COMPARATIVE EXAMPLE 4 The above-mentioned developing sleeve (3) was incorporated in the image forming apparatus of FIG. 1 as the developing sleeve 3, and a print test similar to that of Example 1 was performed using the above-mentioned non-magnetic one-component toner (2). As a result, the density was significantly reduced, and both fog and ghost were bad. Table 1 shows the results.

[0047]

[Table 1]

[0048]

According to the image forming apparatus of the present invention, toner charging and conveyance are stable over a long period of time, and an appropriate charge amount can be maintained even under high temperature and high humidity, and also under low temperature and low humidity. It is possible to obtain excellent image quality free from problems such as background fog, ghost, and uneven density.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an image forming apparatus used for evaluation in an embodiment of a developing sleeve of the present invention.

[Explanation of symbols]

 1: electrostatic latent image holder 2: roller charger 3: developing sleeve 4: developer supply roller 5: layer forming blade

Continued on the front page (72) Inventor Etsushi Tominaga 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Kotaro Yoshihara 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. Rieko 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Satoshi Torigoe 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Masahiro Uchida 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (6)

[Claims] 1. A developing sleeve provided with a coating layer containing at least a phenol resin having a nitrogen atom. 2. The developing sleeve according to claim 1, wherein the thickness of the coating layer is in the range of 1 to 30 μm. 3. The developing sleeve according to claim 1, wherein a powder is dispersed in the coating layer. 4. The developing sleeve according to claim 3, wherein the powder can impart lubricity. 5. The developing sleeve according to claim 3, wherein the powder is molybdenum disulfide. 6. A step of forming an electrostatic latent image on an electrostatic latent image holding member, a step of developing the electrostatic latent image using a developer on a developing sleeve, and a step of developing toner An image forming method including a step of transferring an image onto a transfer body and a step of transferring a developed toner image onto a transfer body, wherein the developing sleeve according to claim 1 is used as the developing sleeve. Image forming method.