JP2012137589A - Developer carrier, developing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer carrier having a surface layer that has high wear resistance, can form a stable toner cloud, and has excellent toner charging property, adhesiveness with an organic insulating layer, and filming resistance, and to provide a developing device having the developer carrier, and an image forming apparatus mounted with the developing device.SOLUTION: The developer carrier is a toner carrier comprising a conductive support, an organic insulating layer formed on the conductive support, a plurality of electrodes arranged at a given interval on the organic insulating layer, and a surface layer covering the plurality of electrodes. The developer carrier is configured to form a toner cloud by applying voltages to the plurality of electrodes and the conductive support to periodically invert electric fields between the electrodes and the conductive support, and thereby, allowing the toner to hop by an electric field between the electrodes. The surface layer comprises at least a copolymer of an imide resin and a phenolic resin.

Description

  The present invention relates to a developer carrier, a developing device including the developer carrier, and an image forming apparatus such as a copying machine, a printer, and a facsimile including the developer.

  In an image forming apparatus such as a copying machine or a printer, a developing device using an electrophotographic process is used. Among such developing devices, a non-contact type developing device that performs development without bringing a developer carrying member that conveys the developer (toner) into contact with a photosensitive member on which an electrostatic latent image is formed is noticeable. Has been. As examples of the non-contact method, a powder round method, a jumping method, a method using an electric field curtain, and the like are known.

The jumping development method (a method in which charged toner particles are supplied between the photosensitive member and the developer carrying member and jumping) requires an applied voltage that is greater than the adhesive force between the toner particles and the developer carrying member. .
In the electric field curtain method, an alternating electric field is applied to a plurality of electrodes arranged at regular intervals inside the developer carrying member to form an electric field curtain by an alternating unequal electric field generated on the surface of the developer carrying member. The toner particles are supplied to hop toner particles, and the toner particles are supplied to the electrostatic latent image. Since the toner particles hop on the surface of the developer carrier, the toner particles and the developer carrier surface Since the adhesion force of the toner becomes substantially zero and the force for peeling off the toner particles from the surface of the developer carrier is not necessary for development, the toner can be sufficiently conveyed to the latent image carrier side at a low voltage. It is.

  The electric field curtain type developing device disclosed in Patent Document 1 uses a developer carrying transport body in which a surface protective layer made of an insulating material or the like is coated on a plurality of electrodes. There is no leakage to the electrode, and the charge of the toner is lost, causing no hopping failure. In addition, the hopping can eliminate the variation in charging of the developer charged in advance to some extent, but it mainly charges the developer between the charging member and the developer carrier, and the surface of the developer carrier is Since it is not formed of a material that takes frictional charging into account, charging variation due to the charging member could not be sufficiently eliminated.

In Patent Documents 2 and 3, the toner particles are supplied onto the surface of the developer carrying member without sufficiently frictionally charging, and the toner particles are hopped on the surface of the developer carrying carrier by an alternating electric field from the beginning of charging. A developer carrying carrier that charges the developer by friction with the carrying carrier is disclosed, and in order to charge toner particles, the surface of the developer carrying carrier is urged to frictionally charge the toner to the normal charging polarity side. It is disclosed to form the material.
The charging by the developer carrying member is gradually charged by friction with the surface of the developer carrying member and can be charged until the charge amount is saturated, so that the toner can be charged more uniformly.

However, even if the surface layer is formed of an insulating material or a material that promotes frictional charging toward the normal charging polarity side of the toner, if the charge between the toner particles and the surface layer becomes too strong, the toner particles and the surface layer are separated. Strong electrostatic adhesion occurs.
This adhesion force exceeds the force that the toner tries to hop by receiving an electric field from the electrode inside the developer carrier, so that the toner particles continue to stick to the surface of the carrier and toner hopping does not occur. If the toner particles are not sufficiently hopped, the toner particles cannot be charged and a toner cloud is not formed, and an abnormal image is generated.

  Even if a toner cloud is formed at the initial stage and a normal image can be output, the toner particles are generated due to a change in the electric field from the electrode inside the developer carrying member due to the abrasion of the roller and a change in the surface condition (roughness etc.) of the roller. Changes in toner charge amount due to changes in the amount of movement on the developer carrier, changes in tackiness of the developer carrier with toner particles (adhesive force of the developer carrier to toner particles), fill The balance between adhesion to the developer carrier and hopping, such as ming, is easily lost, and the toner image sticks to the developer carrier and does not hop sufficiently even when an electric field from the electrode inside the carrier is applied. It is very difficult to output a normal image after passing the paper, for example, the image becomes thinner.

In other words, it is necessary to select a material that has a charge property that can charge the toner particles sufficiently to hop toner particles, and that has high wear resistance. It is considered possible to prevent image output.

A material having high wear resistance, such as an imide resin, needs to be baked at a high temperature of 220 ° C. or higher, typically 280 ° C. or higher. Since it is formed on the organic insulating layer that prevents leakage between the support and the electrode, the surface layer provided on the organic insulating layer and the electrode cannot be fired at a high temperature as described above. Since the polyamic acid unit as an imide resin precursor is difficult to be compatible with other resins, it is difficult to use blends with other resins.

The present invention has been made in view of the above problems, and has an object of forming a stable toner cloud having high wear resistance, toner chargeability, adhesion to an organic insulating layer, and film resistance. a developer carrying member having a surface layer excellent in sex, a developing device having a developer carrying member, and to provide an image forming apparatus equipped with the developing device.

The present invention is solved by the following (1) to (6).
(1) “A conductive support, an organic insulating layer formed on the conductive support, a plurality of electrodes arranged at regular intervals on the organic insulating layer, and a surface layer covering the plurality of electrodes And a voltage is applied to the electrodes and the conductive support so that the electric fields between the plurality of electrodes and the conductive support are periodically reversed. A developer carrier characterized in that a toner cloud is formed by hopping the toner, and the surface layer is composed of a copolymer of at least an imide resin and a phenol resin.
(2) "The developer carrier according to (1) above, wherein the copolymer of the imide resin and the phenol resin is an alternating copolymer",
(3) "The developer carrying member according to (1) or (2) above, wherein the developer carrying member is composed of a resin obtained by curing an alternating copolymer of the imide resin and the phenol resin with a curing agent",
(4) The developer carrying material according to any one of (1) to (3), wherein the insulating layer includes a resin obtained by curing an alternating copolymer of fluoroethylene and a vinyl ether monomer with a curing agent. body",
(5) “Developing device comprising the developer carrying member according to any one of (1) to (4)”,
(6) “An image forming apparatus having at least an electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit, wherein the developing unit is the developer according to any one of (1) to (4). And a voltage applying means for applying a voltage to the electrodes and the conductive support so that the electric field between the plurality of electrodes of the developer support and the conductive support is periodically reversed. An image forming apparatus characterized by. "

  As will be understood from the following detailed and specific description, by forming a surface layer containing a resin obtained by curing a copolymer of an imide resin and a phenol resin with a curing agent, the wear resistance is high and stable. A developer carrier having a surface layer capable of forming a toner cloud and having excellent toner chargeability, adhesion to an organic insulating layer, and filming resistance, a developing device having the developer carrier, and the developing device An image forming apparatus to be mounted can be provided.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 6 is a schematic diagram illustrating an example of a toner cloud state of a developing device. FIG. 3 is a diagram illustrating an example of a configuration of a toner carrier. It is a figure which shows an example of a structure of another toner carrier.

The conductive support of the present invention, an organic insulating layer formed on the conductive support, a plurality of electrodes arranged at regular intervals on the organic insulating layer, and a surface layer covering the plurality of electrodes And a voltage applying means for applying a voltage to the electrode and the conductive support so that an electric field between the plurality of electrodes and the conductive support is periodically reversed. A developer carrying body in which a toner cloud is formed by hopping toner by an electric field to charge the toner, and the surface layer includes a resin obtained by curing at least a copolymer of an imide resin and a phenol resin with a curing agent. explain.

(Conductive support)
As a conductive support, for example, a metal such as Al, Ni, Fe, Cu, or Au, or an alloy thereof, a metal such as Al, Ag, or Au on an insulating substrate such as polyester, polycarbonate, polyimide, or glass, or A thin film of a conductive material such as In ₂ O ₃ or SnO ₂ , carbon black, graphite, aluminum, copper, nickel, or other metal powder, conductive glass powder, or the like is uniformly dispersed in the resin, and the resin is conductive. It is possible to use a cylindrical support formed from a resin substrate imparted with a property, paper subjected to a conductive treatment, or the like.

(Insulating layer)
Any resin can be used as the resin constituting the insulating layer as long as it does not dissolve in the solvent contained in the surface layer coating solution.
Resins having high resistance to organic solvents include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resins, and alkyds. Examples include melamine resins, epoxy resins, fluororesins, and curable resins that form a three-dimensional network structure.
The insulating layer is preferably excellent in heat resistance in order to form a surface layer having excellent wear resistance. A fluororesin is excellent in heat resistance and difficult to decompose even at high temperatures, but has low adhesiveness to the surface layer and easily peels off.
Fluoropolymers obtained by curing alternating copolymers of fluoroethylene and vinyl ether monomers contain copolymer components such as vinyl ether, so they can be dissolved in organic solvents and can easily form uniform thin films using conventional coating methods. It is possible, has excellent resistance to the organic solvent after the thin film is formed, and the insulating layer is not destroyed by the organic solvent or the like when forming the electrode and the surface layer, and has high adhesion to the surface layer described later. Furthermore, when an alternating voltage applied between the conductive support and the electrode is applied, the power consumption is proportional to the dielectric constant of the insulating layer, and the alternating copolymer of fluoroethylene and vinyl ether monomer has a low dielectric constant, Since the toner cloud can be formed with low power consumption, it can be used particularly well.
As the curing agent for curing the resin, an epoxy resin and an isocyanate capable of crosslinking with the active hydrogen group in the resin are preferable, and a polyvalent isocyanate is particularly preferable.
The insulating layer can be formed by a commonly used coating method such as a dip coating method or a spray coating method using an appropriate solvent.

The film thickness of the insulating layer is preferably 1 μm or more and 100 μm or less, more preferably 5 to 50 μm, although it depends on the material.
If it is less than 1 μm, it is difficult to insulate so that no charge leakage occurs between the electrode and the conductive support. When it is thicker than 100 μm, the electric field from the internal electrode becomes weak, and it becomes difficult to release toner particles from the surface layer and to generate electrostatic force capable of hopping.

(Surface layer)
In order to stably negatively charge the toner particles, the surface of the developer carrying member that rubs the toner particles needs to have an appropriate charging property. As described in the toner chargeability evaluation of Comparative Example 1 described later, polycarbonate can be appropriately charged with toner, and can be used on the surface of the developer carrying member. However, since the polycarbonate resin is thermoplastic, its molecular bonding force is weak, and there is a limit to improving the durability.
In addition, as one of the causes of surface layer wear, the molecular chains of the resin in the surface layer can be considered to be broken by an alternating voltage, and in order to improve the wear resistance, the one having a high molecular bonding force or the number of bonds. Many can be used.
As a result of intensive studies on the developer carrier surface layer constituent material, the present inventors have found that a copolymer of an imide resin and a phenol resin that does not contain an amino group and has a large number of bonds does not require a high heating temperature. It was also found that the surface layer obtained by curing the copolymer is excellent in wear resistance and can stably form a cloud of toner for a long period of time.

The copolymer of the imide resin and the phenol resin is a solvent-soluble copolymer in which a phenol resin structure and an imide ring structure are alternately copolymerized to form an imide skeleton in which the imide ring structure is completely closed. It is preferable because the film can be easily formed and the surface layer can be formed by drying at a low temperature of 100 to 200 ° C., and if it has a hydroxyl group in the phenol resin structure part, the reaction between the hydroxyl group and the curing agent It is preferable because the network structure can be increased and a surface layer having high strength and high wear resistance can be formed.

Examples of such a copolymer of imide resin and phenol resin include those represented by the general formula (1) or (2).

（一般式（１）、（２）において、Ｒは水素原子、炭素数１〜９のアルキル基または−Ｏ（ＣＨ_２）_ｌＯＨを示し相互に異なっていても同一でもよい。前記ｌは１〜６の整数を表す。Ｘは−Ｃ（ＣＨ_３）_２−、−ＣＨ_２−、−Ｃ（ＣＨ_３）（Ｃ_２Ｈ_５）−、−Ｏ（ＣＨ_２）Ｏ−、−または−Ｃ（ＣＦ_３）_２−を示し、Ｙは炭素数１〜３のアルキル基、置換基を有してもよいフェニレン基を示す。該置換基は前記Ｒと同じである。Ｚは芳香族テトラカルボン酸二無水物である４価の芳香族基を示し、ｍ、ｎは１以上の整数を示し、前記ｍは１〜５０、好ましくは１〜１５、さらに好ましくは１〜１０である。

(In the general formulas (1) and (2), R represents a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, or —O (CH ₂ ) ₁ OH, which may be the same or different from each other. Represents an integer of ˜6, X is —C (CH ₃ ) ₂ —, —CH ₂ —, —C (CH ₃ ) (C ₂ H ₅ ) —, —O (CH ₂ ) O—, — or —C; (CF ₃ ) ₂ — and Y represents an alkyl group having 1 to 3 carbon atoms and a phenylene group which may have a substituent, the substituent being the same as R. Z is an aromatic tetracarboxylic group. The tetravalent aromatic group which is an acid dianhydride is shown, m and n show an integer greater than or equal to 1, The said m is 1-50, Preferably it is 1-15, More preferably, it is 1-10.

  The molecular weight of the copolymer of the imide resin and the phenol resin is preferably 5,000 to 180,000 from the viewpoint of ease of handling when dissolved in a solvent. Furthermore, it is preferable that it is 5000-60000.

A solvent-soluble imide resin and a phenol resin copolymer in which the phenol resin structure and the ring-closed imide structure are alternately copolymerized are commercially available from Gunei Chemical Industry. Specific examples include GPI-LT, GPI-HT, GPI-NT, and GPI-LM manufactured by Gunei Chemical Industry, and it is preferable to use one or more of these in combination.

Examples of the curing agent include isocyanate and epoxy resin, and the isocyanate curing agent is particularly effective because it has a charge imparting property.
The addition amount of the isocyanate curing agent depends on the curing agent, but is 1.5 times the equivalent to the equivalent, and from the equivalent to 1.1 times the equivalent from the viewpoint of the balance between charge imparting properties and curability. Is preferred.

The surface layer may contain a leveling agent as an additive to the copolymer of imide resin and phenol resin.
As the leveling agent, a known material can be used, but a silicone oil leveling agent capable of imparting a high level of smoothness in a trace amount is particularly preferable. Examples of silicone oils include dimethyl silicone oil, methyl phenyl silicone oil, methyl hydrogen polysiloxane, cyclic dimethyl polysiloxane, alkyl-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, fluorine-modified silicone oil, amino-modified Examples include silicone oil, mercapto-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, higher fatty acid-modified silicone oil, and higher fatty acid-containing silicone oil.
In addition, an appropriate amount of additives such as a plasticizer and an antioxidant can be added to the surface layer.

The surface layer can be formed by a commonly used coating method such as a dip coating method or a spray coating method using one or more solvents capable of dissolving a copolymer of an imide resin and a phenol resin.
Examples of the solvent capable of dissolving the copolymer include NMP, DMAC, DMF, γ-butyrolactone, cyclohexanone, MIBK, methyl ethyl ketone, benzyl alcohol, butyl cellosolve (registered commercial law) and the like.

The thickness of the surface layer may be any as long as the toner particles can be hopped and charged on the surface of the developer carrying member and the exposure of the electrode (91b) to the surface of the developer carrying member can be prevented. 0.5 μm or more and 50 μm or less is preferable.
If it is 0.5 μm or less, it is difficult to insulate so that no charge leakage occurs between the electrode and the toner.
If it is 50 μm or more, the electric field from the internal electrode becomes weak, and it is difficult for the toner to be released from the surface layer and generate an electrostatic force that can be hopped.
Further, when the thickness is 5 to 50 μm, toner hopping is more stably performed.

The developer carrying member of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. In FIG. 1, (1) is a drum-shaped photoconductor rotating in the direction of the arrow (A), (2) is a charging roller for uniformly charging the surface of the photoconductor (1), and (3) is for image information. An exposure device that irradiates the surface of the photoreceptor (1) with laser light or the like, and (4) is a developing device that supplies toner to the electrostatic latent image formed on the surface of the photoreceptor (1).
(5) is a transfer roller for transferring the toner image formed by the developing device (3) on the surface of the photoreceptor (1) onto a transfer material (P) such as transfer paper, and (6) is on the transfer material (P). The cleaning device removes toner remaining on the surface of the photoreceptor (1) from the surface of the photoreceptor (1) after transferring the toner image. (7) is a fixing device that heats and presses the unfixed toner image transferred onto the transfer material (P) and fixes it on the transfer material (P).

  A method for forming a toner image on the transfer material (P) using this image forming apparatus will be described. The surface of the photoreceptor (1) rotating in the direction of the arrow (A) is uniformly charged by applying a predetermined voltage by the charging roller (2). An electrostatic latent image is formed on the surface of the photoconductor (1) by irradiating the surface of the photoconductor (1) uniformly charged with laser light corresponding to desired image information from the exposure device (3). To do. Subsequently, toner is supplied from the developing device (4) to the electrostatic latent image formed in this way, and electrostatically attached to form the electrostatic latent image into a toner image. The toner image thus formed is biased while the surface of the photoreceptor (1) and the transfer material (P) are pressed against each other by the transfer roller (5) and the transfer material (P) is conveyed in the direction of the arrow (B). A voltage is applied to transfer from the surface of the photoreceptor (1) to the surface of the transfer material (P). Thereafter, the toner image transferred onto the transfer material (P) is heated and pressed by the heating roller (7a) and the pressure roller (7b) of the fixing device (7) to be fixed on the transfer material (P). The photoreceptor (1) having the toner image transferred onto the transfer material P in this way removes the toner remaining on the surface of the photoreceptor (1) by the cleaning device (6), and removes the surface of the photoreceptor (1). It is cleaned and again charged uniformly by the charging roller (2). Thereafter, as described above, an electrostatic latent image is formed by the exposure device (3), the electrostatic latent image is converted into a toner image by the developing device (4), and is transferred onto the transfer material (P) by the transfer roller (5). The operation of transferring the toner image and cleaning the surface of the photoreceptor (1) by the cleaning device (6) is repeated.

  The present invention is characterized by the developing device (4) for converting the electrostatic latent image formed on the surface of the photoreceptor (1) into a toner image with toner. As shown in FIG. 1, the developing device (4) in the present embodiment is a developer that supplies toner to the photoreceptor (1) from the opening (8a) in a container (8) that contains toner (T). A carrier (9) is rotatably attached and is rotated in the direction of arrow (C) by a driving means (not shown). Then, the toner (T) is circulated while being stirred by the circulation paddle (10) to slightly charge the toner (T), and the toner (T) is supplied to the surface of the developer carrier (9). The developer carrier (9) supplied with the toner (T) in this way is pumped up while holding the toner (T) on the surface by electrostatic force, and has a predetermined distance from the developer carrier (9). The amount of toner to be pumped is regulated by a blade-like toner regulating member (11) attached to the container (8). As will be described later, the developer carrier (9) is applied with an alternating electric field at the opening (8a) to form a cloud of toner (T). As a result, the toner (T) is electrostatically supplied from the cloud to the electrostatic latent image on the surface of the photoreceptor (1) to form a toner image. Reference numeral (12) in FIG. 1 denotes a toner supply port for supplying replenished toner.

The developer carrier (9) will be described.
As shown in FIG. 2, the developer carrying member (9) has a laminated structure in the order of a conductive support, an insulating layer, an electrode pattern, and a surface layer from the lower layer, and an adhesive is bonded between the electrode pattern and the surface layer. A layer may be provided.

FIG. 3 is a view for explaining a developer carrier (9) of the upper and lower electrode type.
The developer carrier (9) is as shown in FIGS. 3A and 3B (note that FIG. 3A is a cross-sectional view taken along the line AA ′ in the top view of FIG. 3B). In addition, the first electrode and the second electrode are provided, the function of one of the electrodes is assigned to the conductive support (91A), and the conductive support (91A) is placed on the A phase and the insulating layer (95). The electrode pattern (91B) having a plurality of linear electrodes (91Bb) formed on the B phase is a B phase, and toner particles are hopped by a potential difference between the conductive support (91A) and the electrode (91Bb). Is formed.
The electrode pattern (91B) can be formed by processing a copper thin film formed by vapor deposition on the peripheral surface of the cylindrical support (91A) into a desired shape by a photoresist method. It is. There is no particular limitation on the formation method, and in addition to patterning using a photoresist method, it may be formed by drawing using, for example, an ink jet apparatus. As the conductive support (91A), a support made of a material having excellent conductivity such as aluminum or an aluminum alloy can be used. Moreover, there is no limitation in particular about the magnitude | size of an electroconductive support body (91A), What is necessary is just to use what the practitioner of this invention selected suitably. Further, the width (d) of the electrode (91Bb) and the distance (D) between the electrodes (91Bb) are not particularly limited, and may be determined appropriately by the practitioner of the invention. Since the distance (D) can be increased, it is possible to prevent a short circuit, which is preferable.

The formation of the toner cloud is affected by the width (d), the interval (D), the alternating voltage, and the like of the electrode pattern (91Bb). In order to form a good cloud, the electrode width (d) and interval (D) of the electrode pattern (91Bb) may be 40 μm to 250 μm and 85 μm to 500 μm, respectively. Moreover, as an alternating voltage, frequency 100Hz-5KHz and 100V-3KV are suitable.
The material constituting the electrode (91Bb) can be used as long as it is a material having high conductivity. However, it is preferable that the material is a paste because this can be achieved by drawing an electrode pattern.

The comb-teeth electrode type developer carrier shown in FIG. 4 will be described.
The developer carrier (9) is as shown in FIGS. 4A and 4B (note that FIG. 4A is a cross-sectional view taken along line AA ′ in the top view of FIG. 4B). In addition, a first electrode pattern (90A) having a plurality of linear electrodes (90Aa) and a second electrode pattern (90B) having a plurality of linear electrodes (90Bb) include an electrode (90Aa) and an electrode ( 90Bb) are alternately formed in parallel to the axial direction of the developer carrier, and the electrodes (90Aa) and (90Bb) are arranged on the electrode patterns (90Aa) and (90B). A surface layer (98) for protecting 98Bb) is formed.
As the support (93), in addition to the above conductive support, a cylindrical insulating support formed from a synthetic resin such as polyimide, polycarbonate, nylon, fluorine resin, polyacetal, phenol, polystyrene, or aluminum In addition, it is possible to use a cylindrical metal conductive support coated with the above synthetic resin, which has been subjected to metal processing such as aluminum alloy, nickel, titanium, and stainless steel by cutting and polishing.

  In the developer carrier (9) in the present embodiment, a single-phase alternating voltage is used as the alternating voltage power supply, but a plurality of alternating voltage power supplies with different periods can also be used. is there. By applying a voltage so that the positive and negative directions are periodically switched between the two electrodes provided on the carrier, the electric field on the surface of the carrier is periodically reversed in the opposite direction. The toner particles hop between the surface of the photoreceptor (1) and the surface layer (98) of the developer carrier (9) to form a toner cloud, and the toner (T) in this cloud is the photoreceptor (T). The toner image can be formed by electrostatically attracting and adhering to the electrostatic latent image formed on the surface of 1).

As the toner used in the developing device of the present invention, a known toner formed by a pulverization method or a polymerization method can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.

<Insulating layer coating solution 1>
190 parts by weight of an alternating copolymer of fluoroethylene and vinyl ether monomer (Lumiflon LF200MEK (Asahi Glass)) and 35 parts by weight of isocyanate curing agent (TPA-B80E (Asahi Kasei Chemicals)) are mixed with 75 parts by weight of methyl ethyl ketone, and an insulating layer A coating solution was prepared.

<Coating liquid 1 for surface layer>
Solvent-soluble imide resin and phenol resin copolymer (Resitop GPI-LT (manufactured by Gunei Chemical Co., Ltd.)) 53 parts by weight, isocyanate curing agent (TPA-B80E) (Asahi Kasei Chemicals) 22 parts by weight was dissolved in a mixed solution of 161 parts by weight of methyl ethyl ketone and 64 parts by weight of cyclohexanone to prepare a surface layer coating solution 1.

<Developer carrier>
A columnar Al conductive support having a diameter of 16 mm and a length of 230 mm was subjected to dip coating with the above-described insulating layer coating solution to form an insulating layer having a thickness of 18 μm. This was designated as a support (91A) on which an insulating layer had been formed. A 0.8 μm-thick copper foil film, which is a conductive metal foil film, was formed on each support (91A) on which an insulating layer had been formed by vapor deposition. Further, a resist film having a thickness of 5 μm was applied on these copper foil films. A lattice pattern separated by a width d = 100 μm, a length L = 200 mm, and a distance D = 150 μm on a support (91A) having an insulating layer covered with a copper film and a resist film was exposed with a laser drawing machine. Then, after developing in an aqueous Na ₂ CO ₃ solution, etching was performed by immersing in an aqueous FeCl ₃ solution to form an electrode (91Bb) having an electrode pattern (91B) having the same shape as the electrode pattern.
Next, one end of the electrode pattern (91B) of the support (91A) on which the insulating layer is formed in which the electrode having the predetermined electrode pattern (91B) is formed is masked so as to cover the electrode. The surface layer forming coating solution was spray coated and cured at 180 ° C. for 60 minutes to form a surface layer (98) having a maximum film thickness of 28 μm.
In the developer carrier, the electrode at the end of the support (91A) on which the insulating layer is formed is exposed from the surface layer (98), and can be connected to the terminal. The developer carrier (9) thus produced was assembled in the developing device (4).

<Surface layer coating solution 2>
54 parts by weight of a copolymer of solvent-soluble imide resin and phenolic resin (Resitop GPI-NT (manufactured by Gunei Chemical Co., Ltd.)) in which phenolic resin structure and imide ring structure are alternately copolymerized, isocyanate curing agent (TPA-B80E (Asahi Kasei Chemicals) 96 parts by weight was dissolved in a mixed solution of 102 parts by weight of methyl ethyl ketone and 48 parts by weight of cyclohexanone to obtain a coating solution 2 for the surface layer.
A developer carrying member was obtained in the same manner as in Example 1 except that the surface layer coating solution 1 of Example 1 was replaced with the surface layer coating solution 2.

<Surface layer coating solution 3>
61 parts by weight of copolymer of imide resin and phenol resin (Resitop GPI-HT (manufactured by Gunei Chemical)), 39 parts by weight of isocyanate curing agent (TPA-B80E (manufactured by Asahi Kasei Chemicals)) 139 parts by weight of methyl ethyl ketone, 61 parts by weight of cyclohexanone Part of the mixture was dissolved to obtain a surface layer coating solution 3.
A developer carrying member was obtained in the same manner as in Example 1 except that the surface layer coating solution 1 in Example 1 was replaced with the surface layer coating solution 3.

<Surface layer coating solution 4>
Solvent-soluble imide resin and phenol resin copolymer (Resitop GPI-LM (manufactured by Gunei Chemical Co., Ltd.)) 40 parts by weight of isocyanate resin (TPA-B80E) (Asahi Kasei Chemicals) 35 parts by weight was dissolved in a mixed solution of 163 parts by weight of methyl ethyl ketone and 62 parts by weight of cyclohexanone to obtain a coating solution 4 for the surface layer.
A developer carrying member was obtained in the same manner as in Example 1 except that the surface layer coating solution 1 of Example 1 was replaced with the surface layer coating solution 4.

<Insulating layer coating solution 2>
110 parts by weight of alkyd resin (Beckolite M6401-50 (manufactured by Dainippon Ink and Chemicals)), 60 parts by weight of melamine resin (Super Becamine G-821-60 (manufactured by Dainippon Ink and Chemicals)) and 110 parts by weight of methyl ethyl ketone Insulating layer coating solution 2 was obtained.
A developer carrying member was obtained in the same manner as in Example 1 except that the insulating layer coating solution 1 in Example 1 was replaced with the insulating layer coating solution 2.

<Surface layer coating solution 5>
75 parts by weight of a solvent-soluble imide resin and phenolic resin copolymer (Resitop GPI-LT (manufactured by Gunei Chemical Co., Ltd.)) in which phenol resin structure and imide ring structure are alternately copolymerized with 158 parts by weight of methyl ethyl ketone and 68 of cyclohexanone It melt | dissolved in the mixed solution of the weight part, and surface layer coating liquid 5 was obtained.
A developer carrying member was obtained in the same manner as in Example 1 except that the surface layer coating solution 1 of Example 1 was replaced with the surface layer coating solution 5.

[Comparative Example 1]
<Surface layer coating solution 6>
Bisphenol Z-type polycarbonate resin (polymerized compound consisting of structural unit M-15 and having a molecular weight of 50000: Panlite TS-2050 manufactured by Teijin Chemicals) 3 parts by weight, silicone oil (KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.)) 0.002 weight A part was dissolved in a mixed solution of 70 parts by weight of tetrahydrofuran and 30 parts by weight of cyclohexanone to obtain a surface layer coating solution 6.
The surface layer coating solution 6 was used in place of the surface layer coating solution 1 of Example 1, and the surface layer was formed by the same formation method as the surface layer forming method of Example 1, except that Example 1 Similarly, a developer carrying member was obtained.

[Comparative Example 2]
<Surface layer coating solution 7>
75 parts by weight of alkyd resin (Beckolite M6401-50 (Dainippon Ink Chemical Co., Ltd.)), 25 parts by weight of melamine resin (Super Becamine G-821-60 (Dainippon Ink Chemical Co., Ltd.)), methyl ethyl ketone 305 It melt | dissolved in the weight part and obtained the surface layer coating liquid 7.
Example 1 except that the surface layer coating solution 7 was used instead of the surface layer coating solution 1 of Example 1 and the surface layer was formed by the same formation method as the surface layer forming method of Example 1. A developer carrier was obtained in the same manner as above.

[Comparative Example 3]
<Surface layer coating solution 8>
50 parts by weight of silicone acrylic resin (Symac US-352 (manufactured by Toagosei)) and 20 parts by weight of isocyanate curing agent (TPA-B80E (manufactured by Asahi Kasei Chemicals)) are dissolved in 230 parts by weight of 1-butanol and applied to the surface layer. Liquid 8 was obtained.
Instead of the surface layer coating solution of Example 1, the surface layer was formed by the same formation method as the surface layer forming method of Example 1 using the surface layer coating solution 8, and Similarly, a developer carrying member was obtained.

<Voltage application condition to electrode>
An AC bias having an average potential of -200 V at each moment having a peak of -400 V and 0 V at a peak and a terminal attached to the opening of the developing device (4) and the conductive support was applied from an AC power source at a frequency of 5 KHz.
As a toner, BK color toner (wax-free pulverized toner) mounted on imagio Neo C320 was supplied to the developing device (4) for use.
These development devices and toner are incorporated into the black station of imagio Neo C320 to output images, toner charge on developer carrier, toner charge on developer carrier after 50 hours of continuous printing, surface The amount of wear of the layer material, the presence or absence of abnormal images, and the presence or absence of peeling of the surface layer were compared.

Table 1 shows the measurement results and observation results of the examples and comparative examples.
In Examples 1 to 5 and Comparative Examples 1 and 2, no abnormal image output is seen, but in Example 6 and Comparative Example 1, the amount of wear is large.
In Comparative Example 2, since the toner chargeability of the developer carrier surface material is too high, the toner is attracted to the surface of the developer carrier by electrostatic attraction. Therefore, toner hopping did not occur on the surface of the developer carrying member. The image could not be output.
In Comparative Example 3, image output could not be performed because a large number of leaks occurred on the surface layer material surface. This is probably because the acrylic resin has a low molecular bonding force and the molecular chain is cut by an alternating electric field.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 3 Exposure apparatus 4 Developing apparatus 5 Transfer roller 6 Cleaning apparatus 7 Fixing apparatus 7a Heating roller 7b Pressure roller 8 Container 8a Opening 9 Developer carrying body 10 Circulating paddle 11 Toner regulating member 12 Toner supply port A Rotating direction B Conveying direction C Rotating direction D Interval T Toner d Width 90A Electrode pattern 90Aa Electrode 90B Electrode pattern 90Bb Electrode 91A Conductive support 91B Electrode 91Bb Electrode 93 Support 95 Insulating layer 98 Surface layer

JP-A-3-21967 JP 2007-310355 A JP 2007-133388 A

Claims (6)

  A toner having a conductive support, an organic insulating layer formed on the conductive support, a plurality of electrodes arranged at regular intervals on the organic insulating layer, and a surface layer covering the plurality of electrodes A voltage is applied to the electrode and the conductive support so that the electric field between the plurality of electrodes and the conductive support is periodically reversed, whereby the toner is hopped by the electric field between the electrodes. A developer carrier, wherein the surface layer is formed of a copolymer of at least an imide resin and a phenol resin.   The developer carrying member according to claim 1, wherein the copolymer of the imide resin and the phenol resin is an alternating copolymer. 3. The developer carrying member according to claim 1, wherein the developer carrying member is composed of a resin obtained by curing an alternating copolymer of the imide resin and the phenol resin with a curing agent.   4. The developer carrier according to claim 1, wherein the insulating layer includes a resin obtained by curing an alternating copolymer of fluoroethylene and a vinyl ether monomer with a curing agent. 5.   A developing device comprising the developer carrying member according to any one of claims 1 to 4.   An image forming apparatus having at least an electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit, wherein the developing unit has the developer carrying member according to any one of claims 1 to 4. And an image forming apparatus comprising voltage applying means for applying a voltage to the electrodes and the conductive support so that an electric field between the plurality of electrodes of the developer carrier and the conductive support is periodically reversed. apparatus.

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