JP2990017B2 - Developer carrier and developing device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing apparatus for developing a latent image formed on a latent image holding member such as an electrophotographic photosensitive member or an electrostatic recording dielectric in an electrophotographic method to visualize the latent image. ,
And development carrier (developing roller) used in developing device
About.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, US Pat.
A number of methods are known as described in Japanese Patent Publication No. 297691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748, but a photoreceptor made of a photoconductive substance is generally used. Forming an electrical latent image on the photoreceptor by various means, developing the latent image with a developer (toner), and transferring the toner image to a transfer material such as paper as necessary, The image is fixed by heating, pressure, or solvent vapor to obtain a copy.

The developing methods are generally classified into a dry developing method and a wet developing method. However, since the wet developing method involves evaporation of a solvent, it is hardly used at present. In the dry developing method, a two-component developing method such as a magnetic brush developing method mainly using a toner and a carrier has been used for a long time. The disadvantages of the two-component developing method are that it is difficult to keep the mixing ratio of the toner and the carrier constant, and that the carrier deteriorates quickly and the developer must be replaced frequently.

In order to avoid such disadvantages, various methods using a one-component developer consisting of only a toner have been proposed. As such a one-component developer, a one-component magnetic developer in which magnetic particles are contained in a high-resistance resin and toner is conveyed by magnetism is used. As a development method using a high-resistance magnetic toner, there is a method in which toner particles are frictionally charged by friction between toner particles, friction between the toner particles and a sleeve, and the like, and developed by contacting the toner particles with an electrostatic latent image holding member. Are known.

However, in these methods, the number of times of contact between the toner particles and the friction member is small and the triboelectric charging is apt to be insufficient, and the charged toner particles are liable to agglomerate the sleeve due to an increased Coulomb force between the sleeve and the sleeve. Has disadvantages.
Japanese Patent Laying-Open No. 54-43036 proposes a developing method in which the above-mentioned disadvantages are eliminated. This method applies a very thin magnetic toner on a sleeve, triboelectrically charges the magnetic toner, and then applies this to a magnetic field. In this case, the electrostatic image is brought very close to the image below, and the image is developed without contact.

According to this method, the magnetic toner is applied extremely thinly on the sleeve as the developer carrying member, so that the chance of contact between the sleeve and the toner is increased, and sufficient frictional charging is enabled. By supporting the toner and moving the magnet and the toner relatively, the aggregation of the toner particles is dissolved and the toner is sufficiently rubbed with the sleeve. The toner is supported by the magnet and the electrostatic image is formed. An excellent image can be obtained, for example, by developing the toner image while facing the surface without contacting the surface, thereby preventing background fog.

Conventionally, as a developing roller (developing sleeve) generally put into practical use, a metal cylindrical tube made of aluminum, stainless steel, or the like, and a magnet arranged as a magnetic field generating means inside the cylindrical tube are used. Used. The magnet is often used in the form of a magnet roll. The surface of the metal cylindrical tube is often used in a state in which unevenness is appropriately formed by means of sand blasting, sanding or the like to improve the toner conveying force.

However, in such a sleeve, various inconveniences such as uneven toner coat, poor coat, ghost, and reduced density may occur depending on environmental conditions, toner physical properties, sleeve surface conditions, and the like. For example, as the sleeve rotates repeatedly, the charge amount of the toner coated on the sleeve (tribo)
Becomes too high due to the contact with the sleeve, the toner is attracted by the mirror force of the sleeve surface, becomes immobile on the sleeve surface, and does not move from the sleeve to the latent image on the latent image holding member (drum). The charge-up phenomenon tends to occur particularly under low humidity. When such charge-up occurs, the toner in the upper layer becomes less likely to have a tribo, and the amount of developed toner is reduced, resulting in an image in which a line image is thinned, a solid black image has a low image density, and the like.

Further, since the toner layer forming state of the image area (toner consuming section) and the non-image area change and the charging state changes, the position where a solid image having a high image density is once developed is located next to the developing sleeve. When the halftone image is developed at the developing position during rotation, a phenomenon that a solid image appears on the image, that is, a so-called sleeve ghost phenomenon is likely to occur.

Recently, in order to improve the quality of electrophotography,
The toner has a small particle size and fine particles. In order to increase the resolution, sharpness and the like and faithfully reproduce a latent image, a toner having a weight average particle diameter of about 6 to 9 μm is generally used. Further, there is a tendency that the fixing temperature of the toner is lowered for the purpose of shortening the first copy time and saving power. In such a situation, the toner is more likely to adhere to the sleeve electrostatically, and the external surface is subjected to a physical force, so that the sleeve surface is more likely to be contaminated and the toner is fused.

As a method for solving such a phenomenon, Japanese Patent Laid-Open No. 2-105 is used instead of the conventional sleeve of a metal cylindrical tube.
As described in JP-A-181 and JP-A-3-36570, there has been proposed a method of forming a resin film made of resin, conductive fine powder, solid lubricant, or the like on the surface of a metal cylindrical tube and using the resin film in a developing device. It has been done.

By using this method, the development is greatly reduced. However, in the above method,
Insufficient dispersibility of pigments, such as conductive fine powders and solid lubricants, in the resin causes them to be unevenly distributed in the resin coating, especially if the toner used is easy to charge up. A resin film containing conductive fine powder, solid lubricant, etc. in the resin must be formed on the surface of the metal cylindrical tube, and as a result, the resin film strength on the sleeve surface decreases, If used, the resin coating layer on the sleeve surface may be easily scraped or peeled off, which may cause a problem.
Also, when a resin coating containing a large amount of conductive fine powder, solid lubricant, etc. in the resin is formed on the surface of the metal cylindrical tube, the charge imparting property to the toner in a high temperature and high humidity environment becomes insufficient. In some cases, the image density may decrease.

In order to solve such a problem, a method of treating a pigment with a silane-based and titanium-based coupling agent has already been disclosed, as disclosed in Japanese Patent Application Laid-Open No. Hei 1-102485. . However, even with the use of these conventional surface-treated pigments, the dispersibility of the sleeve surface in the resin coating layer was still insufficient, so that the pigment dispersibility was further improved. There is a strong need for a developer carrier excellent in durability and charge imparting property.

Accordingly, it is an object of the present invention to provide a highly durable developer carrier having stable image quality which does not cause deterioration of the film on the carrier surface due to repeated copying or durability and no peeling. Another object of the present invention is to provide a developer carrier capable of obtaining a high-quality image free from a decrease in density or a sleeve ghost over a long period of time even under different environmental conditions.

Another object of the present invention is to reduce the non-uniform charging of the toner layer on the surface of the developer carrier which occurs when a toner having a small particle diameter is used, and to provide a toner having an appropriate charge amount. It is to provide an agent carrier. Another object of the present invention is to provide a stable and high quality image by an electrophotographic apparatus using a developing device constituted by using the developer carrier of the present invention.

[0016]

The above objects are achieved by the present invention described below. That is, the present invention relates to a developer carried by a developer carrying member and used in a developing device for developing a latent image formed on a latent image holding member. And a pigment treated with a reaction product of the following silane coupling agent (A) and the following compound (B) is dispersed and contained in the resin coating layer. And a developing device using the developer carrier. (A) A silane coupling agent having an amino group, an epoxy group or a vinyl group as a functional group. (B) a group capable of reacting with at least one of the functional groups of the silane coupling agent (A), and a hydroxyl group, a carboxyl group, an acid anhydride group, an isocyanate group,
A compound having a group selected from an amino group and a vinyl group.

[0017]

The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, have found that conductive fine powder, solid lubricant, etc. contained in the resin film on the surface of the carrier. Was found to be one of the main causes of these problems, and a pigment that could solve these problems was examined. As a result, it is easy to uniformly disperse in the resin film on the surface of the carrier, the strength of the resin film is not reduced, and the charge amount of the toner can be appropriately adjusted even when used for a long time in different environments. An excellent pigment was developed, and the object of the present invention was achieved by a development carrier using the pigment.

That is, since the pigment used in the present invention has been treated with the reaction product of the silane coupling agent (A) and the compound (B), the pigment on the surface of the developer carrying member in the resin film is not treated. It is considered that since the dispersibility is good, it is possible to impart the properties of the pigment, such as conductivity and lubricant, to the resin film without reducing the strength of the resin film. Further, a reaction product of the silane coupling agent (A) and the compound (B) is:
It is considered that the developer carrier according to the present invention can impart a sufficient amount of charge to the toner even under a high-temperature and high-humidity environment because the toner has a good charge-imparting property to the toner. .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to preferred embodiments of the present invention. The development carrier according to the present invention comprises a resin coating layer formed on a metal cylindrical tube, and a reaction between a specific silane coupling agent (A) and a specific compound (B) in the resin coating layer. It is characterized in that the pigment treated with the product is dispersedly contained.

The pigment used in the present invention has a particle size of 0.01 μm to 50 μm, preferably 0.01 μm to 2 μm.
5 μm, metal powders of aluminum, copper, silver, etc., short metal fibers, carbon black, titanium oxide, tin oxide,
Conductive lubricants selected from metal oxides such as antimony oxide and indium oxide, graphite, molybdenum disulfide, boron nitride, solid lubricants such as zinc stearate,
Alloys and compounds such as magnetite, hematite, ferrite, iron, cobalt, nickel, etc., magnetic powders such as ferromagnetic alloys, rhodamine FB, rhodamine B lake, coloring agents such as phthalocyanine blue, pigment blue, phthalocyanine green, titanium Strongtium acid,
An abrasive such as cerium oxide, silica, aluminum oxide or a mixture thereof can be used.

In the present invention, the surface of the pigment has a silane coupling agent (A) having an amino group, an epoxy group or a vinyl group as a functional group, and the silane coupling agent (A) has the surface. A reaction product with a compound (B) which is a group capable of reacting with at least one of the functional groups and has a group selected from a hydroxyl group, a carboxyl group, an acid anhydride group, an isocyanate group, an amino group and a vinyl group And a pigment whose surface is at least partially covered with the above reaction product (hereinafter simply referred to as a surface-treated pigment) is used.

The surface-treated pigment used in the present invention as described above is preferably obtained by the following various methods, but is not limited to the following method. (Method 1) After adding a silane coupling agent (A) to an aqueous slurry of a pigment and removing water by filtration (or after dehydration treatment with a drier), 60 ° C to 150 ° C (particularly preferably 80 ° C to By performing a heat treatment at 130 ° C.), the pigment reacts with the silane coupling agent. At this time, regarding the dispersion of the pigment in the aqueous slurry, it is preferable to disperse the pigment using a dispersing machine such as a pearl mill or an attritor before (or after) adding the silane coupling agent.

In general, pigments are easily compatible with water and are easily dispersed in aqueous slurries. Therefore, by treating in aqueous slurries in this manner, uniform surface treatment with a silane coupling agent is easily performed. It is more preferable to remove the coupling agent not bound to the pigment by washing with water after the above heat treatment at 60 ° C. to 150 ° C. Next, the pigment treated with the silane coupling agent as described above is mixed and dispersed in a solvent, and contains a specific functional group capable of reacting with a functional group such as an amino group of the coupling agent (A). Compound (B)
Heat treatment in the presence of (preferably 60 ° C to 150 ° C)
By reacting the silane coupling agent (A) on the pigment surface with the compound (B) to obtain a pigment whose surface is covered with these reaction products (hereinafter simply referred to as a surface-treated pigment). .

(Method 2) Suitable solvent (for example, organic solvent)
A silane coupling agent (A) is added to the pigment which has been made into a slurry, and heat treatment is preferably performed at 60 ° C. to 120 ° C., and further, a compound (B) is added to the slurry to form a silane coupling agent. (A) By treating the treated pigment with the compound (B) in the same manner as in the first method,
The surface-treated pigment used in the present invention is obtained.

(Method 3) Suitable solvent (for example, organic solvent)
After adding the silane coupling agent (A) and the compound (B) together to the pigment in a slurry state in
Heat treatment at 50 ° C to obtain the surface-treated pigment used in the present invention. In the second method and the third method, it is preferable to adjust the viscosity of the reaction system to be easily kneaded and dispersed by appropriately adding a solvent.

(Method 4) An appropriate solvent (for example, an organic solvent) is used, and an appropriate coating resin is dissolved therein.
By treating in the same manner as in the second to third methods, the surface-treated pigment used in the present invention is obtained.

In the pigment surface treatment method as described above, the amount of the silane coupling agent (A) added to the pigment varies depending on the particle size and surface structure of the pigment. It is preferable to use the coupling agent (A) in an amount of 0.5 to 10 parts, more preferably 0.5 to 5 parts.

On the other hand, the compound (B) having a functional group capable of reacting with a functional group such as an amino group of the silane coupling agent (A) is 1 to 50 parts, more preferably 1 to 50 parts, per 100 parts of the pigment. Preferably it is used in an amount of 25 parts. When the amount of the compound (B) is less than 1 part, the effect of improving the dispersibility of the pigment by the surface treatment is small. It is not preferable because the viscosity becomes too high. The ratio of the silane coupling agent (A) to the compound (B) (the ratio of the charged amounts) is (silane coupling agent (A) /
The value of compound (B) is preferably from 0.01 to 10, more preferably from 0.02 to 5.

As the silane coupling agent (A) used in the present invention, a reactive functional group comprising at least one of the above-mentioned amino group, epoxy group or vinyl group and active hydrogen such as oxygen A silane compound having both a hydrogen atom bonded to a hetero atom such as an atom, a sulfur atom or a nitrogen atom and a hydrolyzable functional group capable of reacting is preferably used. Further, a silane compound represented by the following general formula (I) is preferably used.

[0030]

Embedded image In the general formula (I), R ¹ is a group having at least a part of the reactive functional group (amino group, epoxy group and / or vinyl group), and R ² is a lower alkyl group such as a methyl group and an ethyl group. , X represents a hydrolyzable functional group capable of reacting with active hydrogen. m is an integer of 1 to 3 (preferably 1 to 2), n is an integer of 0 to 2 and has a relationship of 1 ≦ m + n ≦ 3.

As X in the formula, any functional group which reacts relatively easily with active hydrogen can be used without any particular limitation, but is preferably an alkoxy group or an acyloxy group. The number of such X bonded to the silicon atom is (4-mn), that is, an integer of 1 to 3 in a relationship of 1 ≦ m + n ≦ 3, but is preferably 2 or 3. .

On the other hand, as R ¹ , various groups as shown below are preferably used. The silane compound (I) may be synthesized by a generally known synthesis method, or a commercially available silane coupling agent may be used as it is.

When R ¹ is a group having an amino group, the amino group is a carbon chain (used to include a carbon chain in which a part of carbon atoms constituting the chain is substituted with a hetero atom). The silane compound (I) bonded to the Si atom through the intermediary is preferably used. This amino group is particularly preferably a primary amino group from the viewpoint of reactivity.

Examples of commercially available silane coupling agents as described above include: γ- (2-aminoethyl) aminopropyltrimethoxysilane (Toraysilicone SH6020), and γ- (2-aminoethyl) amino Propyltrimethoxysilane (Toray Silicone SZ6023) ・ Special amino silane compound (Toray Silicone SH60)
26, Toray silicone SZ6050) and the like are preferably used.

When R ¹ is a group having a vinyl group, the vinyl group may be directly bonded to a Si atom,
It may be bonded to a Si atom via a carbon chain. Examples of commercially available silane coupling agents as described above include: γ-methacryloxypropyltrimethoxysilane (Toraysilicone SH6030), N-β- (N-vinylbenzylaminoethyl) -γ-
Aminopropyltrimethoxysilane hydrochloride (Toresilicone SZ6032), Vinyltriacetoxysilane (Toresilicone SH
6075), vinyltriacetoxysilane (Toraysilicone SZ
6300) and the like are preferably used.

When R ¹ is a group having an epoxy group, a silane compound (I) in which the epoxy group is bonded to a Si atom via a carbon chain is preferably used. As commercially available silane coupling agents as described above, for example, • γ-glycidoxypropyltrimethoxysilane (Toray silicone SH6040) and the like are preferably used.

The silane coupling agent (A) described above is
It suffices that the molecule has any one of an amino group, an epoxy group and a vinyl group, but it may have a plurality (or two or more) of these functional groups. Further, if necessary, two or more silane coupling agents (having the same or different types of functional groups) may be used in combination.

The silane coupling agent (A) used in the present invention has been described above. Next, the compound (B) having a functional group capable of reacting with the functional group of the silane coupling agent (A) will be described. . That is, the compound (B) used in the present invention is a functional group capable of reacting with at least one of an amino group, an epoxy group or a vinyl group of the silane coupling agent (A) as described above, and a hydroxyl group. ,
A compound having at least one functional group selected from a carboxyl group, an acid anhydride group, an isocyanate group, an amino group and a vinyl group is used. As such a compound (B), a low molecular weight compound or a high molecular weight compound (having a number average molecular weight of preferably 1,000 or more, more preferably 2,000 or more)
Any of the above can be used.

Hereinafter, the compound (B) having each functional group
A specific example will be described. Compound having a hydroxyl group, for example, lauryl alcohol, myristyl alcohol,
Such as stearyl alcohol (preferably C ₅ -C ₅₀₎
Higher alcohols; phosphate esters (preferably C ₅ -C
Polymers having at least one hydrocarbon group of ₅₀ ); polymers having a hydroxyl group such as hydroxyethyl methacrylate-styrene copolymer; and the like are preferably used.

More specifically, examples of the phosphoric acid ester include monododecyl phosphate, didodecyl phosphate, sesquidecyl phosphate, sesquipropyl phosphate, sesquioctyl phosphate, sesquioleyl phosphate, monohexyl phosphate, dihexyl phosphate, monohexyl phosphate, and monohexyl phosphate. Oleyl phosphate, sesquidodecyl polyoxyethylene (3) phosphate, sesquidodecyl polyoxyethylene (3) phosphate, monododecyl polyoxyethylene (5) phosphate, monooctadecyl polyoxyethylene (5) phosphate, sesquidodecyl polyoxypropylene ( 9) Phosphate, monooctadecenyloxypropylene (8) phosphate and the like are preferably used.

Compounds having a carboxyl group, for example, higher fatty acids (preferably C _{5 to} C ₅₀ ) such as stearic acid and myristic acid; polyesters, styrene-
Compounds having a carboxyl group such as methacrylic acid copolymer are preferably used.

Compound having an acid anhydride group: For example, unsaturated dibasic acid anhydride-vinyl monomer copolymer such as styrene-maleic anhydride copolymer, copolymer of maleic anhydride and α-olefin; dodecenyl higher fatty acids such as succinic acid anhydride (preferably C ₅ -C ₅₀₎ acid anhydrides of the preferably used.

Compounds having an isocyanate group, for example, aromatic diisocyanate compounds such as tolylene diisocyanate and diphenylmethane diisocyanate;
Hydrocarbon chain, such as hexamethylene diisocyanate (preferably C ₅ -C ₅₀₎ aliphatic diisocyanate compounds having a preferably used.

A compound having an amino group represented by the general formula R ³ —NH ₂ , R ³ —NH—R ⁴ , or

Embedded image (R, R ⁴ and R ⁵ each preferably represent a C ₁ -C ₅₀ alkyl group) represented by a primary amine, a secondary amine, or a tertiary amine (for example, stearylamine, dihexadecylamine, Tridecylamine); a polymer having a dialkylamino group or a monoalkylamino group such as a styrene-dimethylaminoethyl methacrylate copolymer; and the like are preferably used.

A compound having a vinyl group, for example, a conventionally known polymerizable monomer such as styrene, methyl methacrylate, or 2-ethylhexyl methacrylate;
Polymers such as 1,2-polybutadiene and polybutadiene modified with a vinyl terminal are preferably used.

The compound (B) described above only needs to have any one of the above-mentioned hydroxyl group, carboxyl group, acid anhydride group, isocyanate group, amino group or vinyl group. Multiple groups (or two types)
You may have. Further, if necessary, two or more kinds of the compounds (B) (having the same or different types of functional groups) may be used in combination.

The silane coupling agent (A) described above and the compound (B) that reacts with the silane coupling agent are preferably used in combination as described below from the viewpoint of improving the dispersibility of carbon black. In the present invention, for the silane coupling agent (A) having an amino group, as the compound (B) that reacts with the silane coupling agent (A), the compound having a hydroxyl group, the compound having a carboxyl group, and the acid anhydride group It is preferable to use a compound or a compound having an isocyanate group.

For the silane coupling agent (A) having an epoxy group, it is preferable to use a compound having a hydroxyl group, a compound having a carboxyl group or a compound having an amino group as the compound (B).
Further, for the silane coupling agent (A) having a vinyl group, it is preferable to use a compound having a vinyl group as the compound (B).

Examples of the binder resin material for dispersing and containing the above-mentioned surface-treated pigment used in the present invention include styrene resin, vinyl resin, polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin Thermoplastic resins such as, fluororesin, cellulose resin, acrylic resin, etc., epoxy resin, polyester resin, alkyd resin, phenolic resin, melamine resin, polyurethane resin, urea resin, silicone resin, polyimide resin, etc. Alternatively, a photocurable resin or the like can be used. Above all, those with release properties such as silicone resin and fluorine resin, or machines such as polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, phenol resin, polyester resin, polyurethane resin and styrene resin Those having excellent mechanical properties are more preferable.

Next, the structure of the developer carrying member according to the present invention will be described. The developer carrier comprises a metal cylindrical tube and a resin coating layer surrounding it. As the metal cylindrical tube, mainly stainless steel, aluminum or the like is suitably used. The resin coating layer is composed of a mixture of the resin and a pigment surface-treated with a reaction product of the silane coupling agent (A) and the compound (B).

In the present invention, the ratio (PB ratio) of the binder resin (B) to the pigment (P) is P / B = 1/20 to 5 /
A range of 1 gives particularly favorable results. At a bander amount exceeding 1/20, the effect of adding the pigment is hardly observed, and
When the amount of the pigment is more than / 1, the resin layer becomes very brittle, and the resin layer is greatly scraped and peeled. The thickness of the resin layer is usually preferably 20 μm or less in order to obtain a uniform thickness, but is not particularly limited to this thickness.

Next, a description will be given of a developing device in which the developer carrier of the present invention is incorporated. In FIG. 2, an image carrier that carries an electrostatic latent image formed by a known process, for example, an electrophotographic photosensitive drum 1, is rotated in the direction of arrow B. Sleeve 8 in developing roller 11
Carries a magnetic toner 4 as a one-component magnetic developer supplied by a hopper 3 and rotates in a direction A so that the toner 4 is transferred to a developing section D where the developing sleeve 8 and the photosensitive drum 1 are opposed to each other. Is transported. Developing sleeve 8
Inside, a magnet 5 is arranged to magnetically attract and hold the magnetic toner 4 on the developing sleeve 8. The developing sleeve 8 has a resin layer 7 coated on a metal cylindrical tube 6. Reference numeral 9 denotes a gap indicating that the developing sleeve and the magnet are in a non-contact state.

The toner 4 obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 1 by friction with the resin layer 7 on the developing sleeve 8. In order to regulate the layer thickness of the magnetic toner 4 conveyed to the developing section D, a regulating blade 2 made of a ferromagnetic metal is moved from the surface of the developing sleeve to about 100 to 300 μm.
It is suspended from the hopper 3 so as to face the developing sleeve 8 with a gap width of m. When the lines of magnetic force from the magnetic pole N1 of the magnet 5 concentrate on the blade 2, a thin layer of the magnetic toner 4 is formed on the developing sleeve 8. Blade 2
For example, a non-magnetic blade can be used. The thickness of the thin layer of the magnetic toner 4 formed on the developing sleeve 8 is preferably smaller than the minimum gap between the developing sleeve 8 and the photosensitive drum 1 in the developing section D.

The present invention is particularly effective for a developing device of a system for developing an electrostatic latent image with such a thin toner layer, that is, a non-contact type developing device. However, the present invention can also be applied to a developing device in which the thickness of the toner layer in the developing section is equal to or greater than the minimum gap between the developing sleeve 8 and the photosensitive drum 1, that is, a contact type developing device. A power supply 10 applies a developing bias voltage to the developing sleeve 8 to fly the magnetic toner 4, which is a one-component magnetic developer, carried on the developing sleeve 8. When a DC voltage is used as the developing bias voltage, a voltage having a value between the potential of the image portion of the electrostatic latent image (the region where the toner 4 adheres and is visualized) and the potential of the background portion is used. 8 is preferably applied. On the other hand, in order to increase the density of the developed image or improve the gradation, an alternating bias voltage may be applied to the developing sleeve 8 to form an oscillating electric field whose direction is alternately reversed in the developing unit D.

In this case, it is preferable to apply to the developing sleeve 8 an alternating bias voltage on which a DC voltage component having a value between the potential of the image portion and the potential of the background portion is superimposed.
Also, in so-called regular development in which toner is attached to a high potential portion of an electrostatic latent image having a high potential portion and a low potential portion to visualize the toner, a toner charged to a polarity opposite to the polarity of the electrostatic latent image is used. On the other hand, in so-called reversal development in which toner is attached to a low potential portion of an electrostatic latent image to make it visible, toner that is charged to the same polarity as the polarity of the electrostatic latent image is used. The high potential and the low potential are expressed by absolute values. In any case, the toner 4 is charged by friction with the developing sleeve 8.

FIG. 3 is a schematic diagram showing a configuration of another embodiment of the developing device of the present invention, and FIG. 4 is a schematic diagram showing a configuration of still another embodiment of the developing device of the present invention. In the developing device shown in FIGS. 3 and 4, as a member for regulating the layer thickness of the magnetic toner 4 on the developing sleeve 8, a material having rubber elasticity such as urethane rubber or silicon rubber, or a metal such as phosphor bronze or stainless steel is used. Elastic plates 20 and 21 made of an elastic material or the like are used. In FIG. 3, the elastic plate 20 is pressed against the rotation direction of the developing sleeve 8 in the forward direction, and in FIG. The feature is that the developing sleeve 8 is pressed against the rotating direction of the developing sleeve 8 in the opposite direction.

The developing device shown in FIGS. 3 and 4 and the other basic constitution are the same as those of the developing device shown in FIG. 2, and those having the same reference numerals indicate basically the same members. 2 to 4 are only schematic examples, and it goes without saying that there are various forms in the shape of the container, the presence or absence of the stirring member, the arrangement of the magnetic poles, and the like. Of course, it can also be used as a two-component developing device using carrier particles.

[0058]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the examples do not limit the present invention in any way. Example 1 (a1) First, 100 g of carbon black having an average particle size of 0.03 μm was taken in 300 g of water, and mixed and dispersed at room temperature using an attritor. Next, 5 g of γ- (2-aminoethylnoaminopropyltrimethoxysilane), which is a silane coupling agent (A) having an amino group, was added, and the mixture was further mixed at room temperature. , Dehydration and heat treatment. Next, the carbon black after the silane coupling agent treatment was added to 300 g of toluene in which 15 g of compound (B) stearic acid was dispersed, and mixed and dispersed using an attritor.
The treatment was performed at 0 ° C. for 2 hours. Thereafter, toluene was removed under reduced pressure to obtain carbon black covered with a reaction product of the silane coupling agent (A) and the compound (B).

(B1) 100 parts by weight of carbon black obtained in (a1) 90 parts by weight of phenol resin 100 parts by weight of methanol 250 parts by weight of isopropyl alcohol

To the above-mentioned coating material, zirconia beads having a diameter of 1 mm were added as media particles, and the mixture was subjected to sand milling.
After time dispersion, the beads were separated using a sieve to obtain a stock solution. Further, this stock solution was diluted with isopropyl alcohol to a solid content of 25% by weight to form a coating solution, and a 10 μm film was formed on a stainless steel support having a diameter of 20 mm by a spray method. Heating was performed for 30 minutes to cure, thereby preparing a developer carrying member of this example.

Next, the developer carrier obtained in (b1) was replaced with G
A built-in image output test was performed on a P55 (copier made by Canon Inc.).・ Styrene acrylic resin 100 parts by weight ・ Magnetite 80 parts by weight ・ Negative charge control agent (3,5-di-tert-butylsalicylate complex) 2 parts by weight ・ Low molecular weight polypropylene 3 parts by weight According to the production method, kneading, pulverization, classification and the like are performed, and the volume average particle diameter is 7.5 μm, the number% of particles having a particle diameter of 4 μm or less is 16%, and the particle number of 12.7 μm or more is 0.7% by weight. And colloidal silica (1.0%) was externally added with a Henschel mixer to obtain a toner. The measurement of the particle size distribution was based on a Coulter Counter TA-II.

As a result of the image formation test, 23.5 ° C., 60%
The image density under a normal temperature and normal humidity environment of RH is as high as 1.43,
In addition, a good image free of ghost and density unevenness was obtained. Further, the image density is as high as 1.45 and the ghost level is good even in a low-temperature and low-humidity environment of 15 ° C. and 10% RH, and also in a high-temperature and high-humidity environment of 32.5 ° C. and 85% RH. The image density was as high as 1.37, and neither density unevenness nor ghost occurred. As described above, the change in image density and image quality was small even under different environmental conditions. Furthermore, the image density was stable even when 100,000 sheets were repeatedly copied under different environmental conditions, and density unevenness and ghost did not cause any problem.

Example 2 (a2) 100 g of carbon black having an average particle size of 0.03 μm was added to a mixture of 300 g of toluene and 15 g of styrene as a compound (B), and mixed and dispersed at room temperature using an attritor. Next, vinyltrimethoxysilane (γ-) as a silane coupling agent (A) having a vinyl group
Resin Silicone SZ6300) (2 g) and 2,2-azobis (2,4,4-trimethylpentane) 0.75 were added, and the mixture was treated at 120 ° C. under closed stirring for 2 hours.
The liquid component was removed under reduced pressure to obtain carbon black covered with a reaction product of the silane coupling agent (A) and the compound (B).

(B2) The procedure of Example 1 was repeated except that 100 parts by weight of the carbon black obtained in (a1) was replaced with 100 parts by weight of the carbon black obtained in (a2).
When a developer carrying member was prepared in the same manner as in 1) and the same copying was performed, good results were obtained as in Example 1.

Example 3 (a3) In place of 100 g of 0.03 μm carbon black, 100 g of 7.5 μm graphite was used, and the same procedure as in (a1) of Example 1 was repeated, except that the silane coupling agent (A) and the compound were used. Graphite covered with the reaction product with (B) was obtained. (B3) 100 parts by weight of the carbon black obtained in (a1) of Example 1 (b1), graphite 10 obtained in (a3)
A developer carrier was prepared in the same manner as in Example 1 except that the amount was changed to 0 parts by weight, and copying was performed in the same manner as in Example 1. As a result, good results were obtained as in Example 1. .

Comparative Example 1 A developer-carrying member was prepared in the same manner as in Example 1 except that the carbon black pigment used in Example 1 was used without treatment, and the same copying was performed. As a result, the image density under a high temperature and high humidity environment of 32.5 ° C. and 85% RH was as low as 1.15. Further, if 100,000 copies are continuously repeated, peeling and abrasion of the resin film on the surface of the developing carrier may occur, and the density unevenness and ghost may be deteriorated. In particular, the image density may be remarkably reduced in a low-temperature and low-humidity environment. And the initial density 1.43 becomes 1.1 after 100,000 sheets.
It has dropped to 9.

Comparative Example 2 A developer-carrying member was prepared in the same manner as in Example 3 except that the graphite pigment used in Example 3 was used without treatment, and the same copying was performed. As a result, similar to Comparative Example 1, good results were not obtained.

[0068]

[Evaluation Results] The copies obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were observed, and image density, density unevenness and ghost were evaluated. The evaluation results are shown in Tables 1 to 3. Was. The evaluation criteria are shown below. ○: very good, ○ △: good, △: slightly bad, ×: very bad

[0069]

[Table 1] Table 1-1 Evaluation results

[0070]

[Table 2] Table 1-2 Evaluation results

[0071]

[Table 3] Table 1-3 Evaluation results

[0072]

As described above, according to the present invention, by using a developer carrier having a resin coating layer in which a specific surface-treated pigment is dispersedly contained, the resin coating by repeated copying or durability can be obtained. Since layer deterioration and peeling do not occur, it is possible to provide a high-quality image with high image density over a long period of time and without density unevenness and ghosting. Furthermore, according to the present invention, even under different environmental conditions, the change in image density is small, and it is possible to maintain an appropriate charge of the toner even under low-temperature and low-humidity environmental conditions. Density unevenness,
Since no ghost or the like occurs, a high-quality image can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic view of a developing device using a conventional developing roller on which a resin film is not formed.

FIG. 2 is a schematic diagram of a developing device using a developer carrier having a resin film formed thereon according to the present invention.

FIG. 3 is a view showing a developing device having a developer carrier on which a resin film according to the present invention is formed, and having a different type of regulating member for the developer layer.

FIG. 4 is a view showing a developing device having a developer carrier on which a resin film according to the present invention is formed, wherein the type of regulating member for the developer layer is different.

[Explanation of symbols]

 1: photosensitive drum (electrostatic latent image carrier) 2: magnetic regulation blade 3: container 4: developer (toner) 5: magnet roll 6: metal cylindrical tube 7: resin coating layer 8: developing sleeve 9: void 10: Developing bias power supply 11: developing roller 12: developing roller 13: developing sleeve 20: elastic regulating blade 21: elastic regulating blade N1, S1, N2, S2: magnetic pole

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Fujishima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuki Saiki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-4-76577 (JP, A) JP-A-1-101375 (JP, A) (58) Fields studied (Int. Cl. ⁶ , DB name) G03G 15/08

Claims (2)

(57) [Claims] 1. A developer carrier used in a developing device for developing a latent image formed on a latent image holding member, the developer being carried and transported by the developer carrier. A resin coating layer is formed, and a pigment treated with a reaction product of the following silane coupling agent (A) and the following compound (B) is dispersed and contained in the resin coating layer. Characteristic developer carrier. (A) A silane coupling agent having an amino group, an epoxy group or a vinyl group as a functional group. (B) a group capable of reacting with at least one of the functional groups of the silane coupling agent (A), and a hydroxyl group, a carboxyl group, an acid anhydride group, an isocyanate group,
A compound having a group selected from an amino group and a vinyl group. 2. A developer carrying member, wherein a one-component developer contained in a developing container is carried on a developer carrying member, and a developer layer regulating member forms a thin film of the developer on the developer carrying member. The developer carrying device according to claim 1, wherein the developer carrying device transports the developer to a developing unit facing the latent image carrier and develops the latent image formed on the latent image carrier. A developing device characterized by being a body.