JP2955310B2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a non-magnetic one-component developing method for an electrostatic latent image formed on an electrostatic latent image holding member in an electrophotographic apparatus. The present invention relates to a developing device suitable for visualizing an image with an agent.

(Prior Art) As a developing device for visualizing an electrostatic latent image formed on an electrostatic latent image holding member with a non-magnetic one-component developer, a main part configuration is shown in cross section in FIG. There is known a developing device which is constructed or operates. That is, the non-magnetic one-component developer 2 charged in the developer (toner) container 1 is
The developer is conveyed to the developing roller 5 by the developer supply roller 4 or the like. Developer 2 conveyed to developing roller 5
Is thinned and held on the surface of the developing roller 5 while passing a prescribed charge while passing through a region of the developer layer thickness regulating member 6 whose end is arranged close to the outer peripheral surface of the developing roller 5. Is done. The electrostatic latent image formed on the latent image holding member 7 is developed by electrolysis using the developer carried on the surface of the developing roller 5 in this manner, and the latent image holding member 7 is developed.
Is a non-magnetic one-component developing device for visualizing electrostatic information recorded in the image forming apparatus.

By the way, the developing roller 5 usually has a structure in which a part of the developing roller is cut away and shown in perspective. That is, for example, a resistance value of at least an outer peripheral surface using a polyurethane resin or a polyurethane elastomer as a binder is 10%.
^It has a conductive layer 5a of ¹⁰ Ωcm or less, and the inside of the conductive layer 5a is made of oil-resistant rubber having a hardness of 40 degrees or less, preferably 35 degrees or less, measured with an A-type hardness tester of JIS K6301. Elastic layer
5b. In FIG. 2, reference numeral 5c denotes a metallic roller gas, and the elastic layer 5b
Examples of the oil-resistant rubber that forms the rubber include EPDM, urethane, silicone, chloroprene, NBR, and the like. A conductive material obtained by dispersing a conductive filler in these may be used.

(Problems to be Solved by the Invention) However, the following problems are recognized in the above-described developing device. That is, at least the surface of the developing roller 5 used in the developing device is coated with a conductive paint to form a required conductive layer 5a. However, when the electrostatic chargeability of the coating film of these conductive paints is measured, many of them have almost no chargeability even if the polarity of the developer is copper or reverse. For this reason,
The developer cannot be consciously given an appropriate charge amount,
Defective developer layers and poor transport such as developer spills and unevenly deposited developer layers are likely to occur, and practically sufficient images cannot be obtained in many cases.

In the development process, a negatively chargeable developer is used, a developing roller and a developer layer pressure regulating member,
There is also known an improvement focusing on the fact that a member such as an intermediate roller, which imparts a triboelectric charge to a developer, is positively charged so that the developer can be sufficiently charged. For example, in the case of a developing roller in which a solvent-based paint is applied to the surface of the developing roller, a dye or the like (eg, azine-based nigrosine, nigrosine bases, nigrosine derivative, benzomethyl-hexyldecyl) is used to control the charging of the developing roller. An organic quaternary ammonium salt such as ammonium chloride). However, most of these charge controlling agents are insoluble or slightly soluble in a solvent, so that they are not easily dispersed in a coating material, thereby making it difficult to exhibit their functions and increasing the amount of addition.

The present invention has been made in order to solve the above-described problems, and a developing device configured to be able to easily and always reliably apply a required charge amount to a developer carried and conveyed by a developing roller. For the purpose of providing.

[Constitution of the Invention] (Means for Solving the Problems) In the present invention, a developer is supplied to a developing roller having a two-layer structure having elasticity, and a thin layer of the developer is formed on the outer peripheral surface of the developing roller by a regulating member. And a mechanism for giving a charge,
A mechanism was provided for bringing the thin developer layer close to or in contact with the electrostatic latent image holding member, applying a developer to the electrostatic latent image held on the electrostatic latent image holding member, and developing the visible image. In the developing device, the outer peripheral layer of the developing roller that imparts a triboelectric charge to the developer has the following formula: (Wherein, R ₁ is a hydrogen atom or an alkyl group) and 60 to 99 parts by weight of a repeating unit represented by the following formula: (Wherein, R ₂ is a hydrogen atom or an alkyl group, R ₃ is an alkylene group, R ₄ , R ₅ and R ₆ are alkyl groups, and the alkyl group and the alkylene group have 1 to 12 carbon atoms. And a quaternary ammonium salt group-containing copolymer having a weight average molecular weight in the range of 300 to 25,000, preferably in the range of 3000 to 8000. It is characterized by containing. Hereinafter, the above substance will be referred to as a copolymer.

Thus, in the present invention, in the development process, a negatively chargeable developer is used, and a member for imparting a triboelectric charge to the developer, such as a developing roller, a developer layer thickness regulating member, and an intermediate roller, is positively adjusted. It has been made paying attention to the fact that sufficient charge can be given to the developer by charging.

The copolymer according to the present invention is not only easy to handle because it is easy to use in a solvent, but also excellent in dispersibility and compatibility with paints because it is a resin-based one, and the effect can be expected with a small amount of addition. There is. For example, when the above-mentioned copolymer according to the present invention is contained in the developer layer thickness regulating member made of silicone rubber, the desired effect can be obtained by adding a small amount of the copolymer because of excellent compatibility with the main binder.

A method for producing a quaternary ammonium salt group-containing copolymer having the above structural formula is disclosed in JP-A-63-60458.

In the present invention, by adding 0.01 to 80 parts by weight of the copolymer, preferably 0.1 to 10 parts by weight of the copolymer on the surface of the phenomenon roller and the developer layer thickness regulating member, the surface of the developing roller and the like This is to improve triboelectric charging. For example, when a conductive paint is applied to a developing roller and used, an appropriate amount of the copolymer is dissolved in a diluent of the conductive paint in advance, mixed and dispersed with the conductive paint main body, and this is mixed with a developing roller. Is applied using a dipping, spraying, roller method or the like, dried and incorporated into a developing device. The thickness of the conductive layer applied here is 5 μm.
m to 200 μm, preferably 30 μm to 120 μm. Further, when improving the surface triboelectric charging property of the developer layer thickness regulating member, for example, when using silicone rubber as the developer layer thickness regulating member, 0.01 to 40 parts by weight, preferably 0.1 wt. After adding 10 parts by weight from a part and dispersing and containing in a kneader such as a kneader,
It is vulcanized and molded and incorporated into a developing device as a developer layer thickness regulating member.

In the developing device having the above configuration, a known non-magnetic one-component developer (toner) including a binder resin, a coloring material, a charge control agent, a wax, and a caking inhibitor is used.

For example, as the binder resin, polystyrene, poly-
Monopolymers of styrene such as P-chlorostyrene and polyvinyltoluene and substituted products thereof, for example, styrene-P-
Vinyl toluene copolymer, styrene-propylene copolymer, styrene-vinyl toluene copolymer, styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-acrylic acid copolymer, styrene-
Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-methacryl Octyl acid copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer,
Styrene-vinyl ethyl ether copolymer, styrene-
Styrenes such as vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-acrylonitrile-indene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Copolymer, polymethyl methacrylate,
Polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic Hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like may be used alone or as a mixture.

In addition, carbon black and various dyes and pigments as colorants and charge control agents, low molecular weight polyethylene and polypropylene as anti-offset agents, hydrophobic silica and metal oxides as anti-caking agents, PMMA,
Spherical resin fine particles such as Teflon and styrene can be exemplified.

(Function) A member for imparting a required triboelectric charge to the developer (toner),
That is, by including the copolymer on at least one surface of the developing roller and the developer layer thickness regulating member, it becomes possible to give the developer an effective charge required for development, and a sharp line image, uniform Not only can a solid image be prepared and output reliably, but also the life of the developing device can be extended.

In order to confirm the effect of the copolymer, the amount of charge was measured using an electrostatic coating surface analyzer (manufactured by Toshiba Chemical Corporation) schematically shown in FIG. The measurement conditions were set to 25 ° C. and an environmental atmosphere of 85 parts by weight, and using a spherical iron component, the measurement was carried out at 1.30 g per sprinkling amount, 5 sec. Sprinkling time, 60 ° gradient, and 5 measurement points per sample. However, those without addition of the copolymer according to the present invention were 80 × 10 ⁻³ C or less, whereas those with the copolymer according to the present invention added were 80 × 10 ⁻⁹ C.
As described above, it is apparent that the chargeability is clearly improved.

In FIG. 3, reference numeral 15 denotes a reference iron powder inlet, 16 denotes an inclined plate (sample table), 17 denotes a tray, 19 denotes an insulating plate, 20 denotes an electrometer, and 21 denotes a meter connection terminal.

(Example) Next, an example of the present invention will be described.

Example 1 A solvent prepared by dissolving 5 g of the above copolymer (FCA201-B3 manufactured by Fujikura Kasei) in 100 g of a mixed solvent of tetrahydrofuran THF: -methylethylketone MEK (1: 1) in 100 g of polyurethane conductive paint Sparex manufactured by Nippon Milactran Co., Ltd. The mixture was diluted and dispersed. This mixed dispersion was applied to the surface of a phenomenon roller (urethane rubber) by a dipping method, and then dried with a drier for 20 minutes to prepare a developing roller.

Thus the surface resistance of the obtained developing roller 1 × ⁵ 5 Ω · cm
The thickness of the formed coating film was 100 μm.

The developing roller configured as described above was replaced with the developing roller 5 of the developing device whose main configuration is shown in FIG. 1, and a similar developing device was experimentally produced to perform image formation under the following conditions.

The developing material 2 is a non-magnetic one component having a volume average particle diameter of 10 μm, comprising 92 parts by weight of a polyester resin, 4 parts by weight of carbon, 2 parts by weight of a low molecular weight polypropylene, 2 parts by weight of a metal dye, and 0.5 part by weight of an external additive silica. The latent image carrier (OPC) 7 is set at a surface speed of 50 mm / S using a system developer, and is uniformly charged to a surface potential of −500 V by corona discharge from the charger 9 to form a ray exposure device 8. After recording the image information with the laser, the surface was rotated at a speed of 100 mm / S, and the developing roller 5 to which -200 V was applied was pressed against the latent image carrier (photoconductor) 7 to perform required development. The developed powder image was transferred to recording paper in a transfer device 11 by a DC corona discharge of 6 kV, and then thermally fixed.

The image after the transfer was a clear high-density image of a line image and a uniform solid image. Also, the images after the life test of 50,000 sheets were clear images without deterioration while maintaining the initial state. Furthermore, an excellent image was obtained even under high temperature and high humidity conditions.

Example 2 Into 100 g of a conductive paint electropack manufactured by Taitai Kako Co., Ltd., 5 g of isocyanate and a solvent obtained by dissolving 5 g of the copolymer according to the present invention (FCA201-B3 manufactured by Fujikura Kasei) in 100 g of toluene were mixed and diluted. Dispersed. After applying this mixed dispersion to a developing roller (urethane rubber) surface by dipping,
It was dried for 20 minutes in a drier to prepare a developing roller. The surface resistance of the thus obtained developing roller was 2 × 10 ⁶ Ω · cm, and the thickness of the formed coating film was 100 μm.

The developing roller configured as described above was replaced with the developing roller 5 of the developing device whose main configuration is shown in FIG. 1, and a similar developing device was prototyped to produce an image under the following conditions.

The developer 2 is composed of 92 parts by weight of a polyester resin, 4 parts by weight of carbon, 2 parts by weight of a low molecular weight polypropylene, 2 parts by weight of a gold-containing dye, and 0.5 part by weight of an external additive silica. The rotation of the latent image carrier (OPC) 7 is set to a surface speed of 50 mm / S using the system developer 2,
After uniformly charging to a surface potential of −500 V by corona discharge from the charger 9 and recording image information with a laser as the exposure device 8,
The developing roller 5 rotated at a surface speed of 100 mm / S and applied with -200 V is pressed against the latent image carrier (photoconductor) 7,
The required development was performed. Transferring the developed powder to transfer device 11
After transferring to recording paper with 6kV DC corona discharge at
Heat fixed.

The image after the transfer was a clear high-density image of a line image and a uniform solid image. Also, the images after the life test of 50,000 sheets were clear images without deterioration while maintaining the initial state. Furthermore, an excellent image was obtained even under high temperature and high humidity conditions.

Comparative Example 1 100 g of polyurethane conductive paint SPAREX manufactured by Nippon Milactran Co., Ltd. was diluted and dispersed with 100 g of a mixed solvent of THF: MEK (1: 1), and this was applied to the surface of a developing roller (urethane rubber) by dipping and then dried. Drying was performed for 20 minutes in a vessel to produce a developing roller. The surface resistance of the developing roller thus obtained is 3.1 × 10 ⁵ Ω · cm, and the thickness of the formed coating film is 105 μm.
Met.

Using the developing roller 5 configured as described above, a developing device having the same configuration as the developing device whose main configuration is shown in FIG. 1 was experimentally produced, and image formation was performed under the following conditions.

As the developer, a non-magnetic one-component system having a volume average particle diameter of 10 μm comprising 92 parts by weight of a polyester resin, 4 parts by weight of carbon, 2 parts by weight of a low molecular weight polypropylene, 2 parts by weight of a metal-containing dye, and 0.5 part by weight of an external additive silica. Using the developer 2, the rotation of the latent image carrier (OPC) 7 was set to a surface speed of 50 mm / S, and the surface was uniformly charged to −500 V by corona discharge from the charger 9. After recording the image information with a laser, the developing roller 5 rotated at a surface speed of 100 mm / S and applied with -200 was pressed against the latent image carrier (photoconductor) 7 to perform required development. The developed powder image was transferred to recording paper by a transfer device 11 using a DC corona discharge of 6 kV, and then thermally fixed.

In the image after the transfer, the line image was clear, but the solid image was an image showing uneven conveyance failure.

Example 3 To 1000 g of silicone rubber, 50 g of the above copolymer (FCA201-B3 manufactured by Fujikura Kasei) and 150 g of aerosil-like silica were added, kneaded in a kneader for 20 minutes at 120 ° C., and 10 g of benzoyl peroxide was added. 200 at 150 ° C for 20 minutes
Vulcanized at 4 ° C. for 4 hours. This was formed into a metal jig to form a developer layer thickness regulating member.

The currently configured developer layer thickness regulating member is replaced with the developer layer thickness regulating member 6 of the developing device whose main configuration is shown in FIG. 1, and a similar developing device is constructed and manufactured under the following conditions. Image was drawn.

The developer 2 is composed of 92 parts by weight of a polyester resin, 4 parts by weight of carbon, 2 parts by weight of a low molecular weight polypropylene, 2 parts by weight of a gold-containing dye, and 0.5 part by weight of an external additive silica. The latent image carrier (OPC) 7 is set at a surface speed of 50 mm / S using a system developer, and is uniformly charged to a surface potential of −500 V by corona discharge from the charger 9. After recording image information with a laser, the developing roller 5 was rotated at a surface speed of 100 mm / S, and a developing roller 5 to which -200 V was applied was pressed against the latent image carrier (photoconductor) 7 to perform required development. The developed powder image is transferred to the transfer device 11
After transferring to recording paper with 6kV DC corona discharge at
Heat fixed.

The image after the transfer was a clear high-density image of a line image and a uniform solid image. Also, the images after the life test of 50,000 sheets were clear images without deterioration while maintaining the initial state. Furthermore, an excellent image was obtained even under high temperature and high humidity conditions.

Comparative Example 2 A developer layer thickness regulating member was produced in the same manner as in Example 3 above, except that the above-mentioned copolymer was not contained in the silicone rubber.

Using the developer layer thickness regulating member, a prototype of a developing device similar to the developing device whose main configuration is shown in FIG. 1 was prototyped, and image formation was performed under the following conditions.

The developer 2 is composed of 92 parts by weight of a polyester resin, 4 parts by weight of carbon, 2 parts by weight of a low molecular weight polypropylene, 2 parts by weight of a gold-containing dye, and 0.5 part by weight of an external additive silica. The latent image carrier (OPC) 7 is set at a surface speed of 50 mm / S using a system developer, and is uniformly charged to a surface potential of −500 V by corona discharge from the charger 9. After recording image information with a laser, the developing roller 5 was rotated at a surface speed of 100 mm / S, and a developing roller 5 to which -200 V was applied was pressed against the latent image carrier (photoconductor) 7 to perform required development. The developed powder image is transferred to the transfer device 11
In the above, after transfer to recording paper by a 6 kV DC corona discharge, heat fixing was performed.

In the image after the transfer, although the sharpness of the line image was clear, the solid image was an image exhibiting uneven conveyance failure.

In the above description, the configuration in which either the developing roller or the developer layer thickness regulating member contains the above-described copolymer has been described, but a configuration in which the above-described copolymer is contained in both may be employed. In short, at least one of the constituent members serving to impart a required triboelectric charge to the developer used may have a configuration in which the copolymer according to the present invention is contained, and for example, a developer supply roller may be used. . Further, the content region of the copolymer may be only a surface portion involved in giving a triboelectric charge.

[Effect of the Invention] As described above, at least the surface of a component serving to impart a triboelectric charge to a developer has the following formula: (Wherein, R ₁ is a hydrogen atom or an alkyl group) and 60 to 99 parts by weight of a repeating unit represented by the following formula: (Wherein, R ₂ is a hydrogen atom or an alkyl group, R ₃ is an alkylene group, and R ₄ , R ₅ and R ₆ are alkyl groups.) By containing a quaternary ammonium base-containing copolymer having a weight average molecular weight in the range of 300 to 25,000, preferably in the range of 3,000 to 8,000, the development characteristics are clear,
It has become possible to always obtain a uniform high-density solid image easily. In addition, it can be said that the present invention brings many practical advantages, such as being able to maintain the required functions for a long period of time and responding to changes in the characteristics of the developer due to the environment.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a main part of a developing device, FIG. 2 is a partially cutaway perspective view showing a configuration of a developing roller, and FIG. 3 is a principle of an electrostatic coating film surface analyzing device for measuring a charge amount. FIG. DESCRIPTION OF SYMBOLS 1 ... Developer container 2 ... Developer 3 ... Stirrer 4 ... Developer supply roller 5a ... Developing roller 5b ... Conductive layer 6 ... Elastic body layer 7 ... Latent image holding body 8 ... Exposure device 9 Charger 10 Cleaning unit 11 Transfer device 12 Recovery blade 13 Protection resistor 14 DC power supply

Continued on the front page (72) Inventor Hiroki Takano 1 Toshiba-cho, Komukai-shi, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Research Institute, Inc. Inside Toshiba Research Institute (72) Inventor Kouji Endo 2-6-13 Nakameguro, Meguro-ku, Tokyo Tokyo Electric Co., Ltd. (72) Inventor Yoshimitsu Otaka 2-6-13 Nakameguro, Meguro-ku, Tokyo East (56) References JP-A-62-24280 (JP, A) JP-A-63-60458 (JP, A) JP-A-61-149969 (JP, A) (58) Fields investigated Int.Cl. ⁶ , DB name) G03G 13/08-13/095 G03G 15/08-15/095

Claims (1)

(57) [Claims] A developing roller having a two-layer structure having elasticity, a developer supply means for supplying a developer to an outer peripheral surface of the developing roller, and a developer supplied at an end close to the outer peripheral surface of the developing roller. A regulating member that reduces the thickness and provides an electric charge; and an electrostatic latent image holder that develops an electrostatic latent image held close to or in contact with the thinned developer layer into a visible image. In the developing device, the outer peripheral layer of the developing roller that imparts a triboelectric charge to the developer has the following formula: (Wherein, R ₁ is a hydrogen atom or an alkyl group) and 60 to 99 parts by weight of a repeating unit represented by the following formula: (Wherein, R ₂ is a hydrogen atom or an alkyl group, is an R ₃ alkylene group, and R ₄ , R ₅ and R ₆ are an alkyl group;
The alkyl group and the alkylene group have 1 to 12 carbon atoms. A developing device characterized by containing a quaternary ammonium base-containing copolymer having a weight-average molecular weight in the range of 300 to 25,000, the copolymer comprising 40 to 1 parts by weight of the repeating unit represented by the formula (1).