JPH03192377A - Developing device - Google Patents

Abstract

PURPOSE:To easily obtain a high-density image having distinct developing charac teristic and uniform solid image by making the surface of a structural member for adding triboelectric charge to developer contain a complymer containing quaternary ammonium salt base having the specified structure of repetition unit. CONSTITUTION:By sticking the copolymer containing quaternary ammonium salt base which is the copolymer consisting of 40-1 pts. wt. repetition units shown by formulas (1) and (2) and is within a range that weight average molecu lar weight is 300-25,000, desirably 3,000-8,000, to the surface of any one of a developing roller, a regulating member and a developer supplying roller for adding the triboelectric charge to the developer, the surface triboelectrification ability of the developing roller, etc., is improved. As to a sticking method, in the case of applying conductive paint to the developing roller, the proper quantity of the above copolymer is previously dissolved in the diluent of the conductive paint and is mixed and dispersed in the conductive paint main body, then it is desirable to apply and dry the paint by using dipping, spray or roller methods to the developing roller.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention is an electrophotographic apparatus in which an electrostatic latent image formed on an electrostatic latent image carrier is developed using a non-magnetic component. The present invention relates to a developing device suitable for visualizing an image using an agent.

(Prior Art) A developing device that visualizes an electrostatic latent image formed on an electrostatic latent image holder using a non-magnetic component developer is shown in FIG. 1 in cross section. A developing device configured and operated as follows is known. That is, a non-magnetic component developer 2 placed in a developer (toner) container 1 is conveyed to a developing roller 5 by an agitator 3, a developer supply roller 4, and the like. The developer 2 conveyed to the developing roller 5 is
By passing through the region of the developer layer thickness regulating member 6 whose end is disposed close to the outer circumferential surface of the developing roller 5, the developer is held in a thin layer on the surface of the developing roller 5, while being given a prescribed electric charge. Ru. The electrostatic latent image formed on the latent image carrier 7 is developed by the developer carried on the surface of the developing roller 5 using an electric field, and the electrostatic charge recorded on the latent image carrier 7 is This is a non-magnetic component developing device that visualizes digital information.

Incidentally, the developing roller 5 usually has a structure shown in perspective with a portion cut away in FIG. 2.

That is, for example, at least on the outer circumferential surface, there is a conductive layer 5a having a resistance value of 10"Ω. It has a structure comprising an elastic layer 5h made of oil-resistant rubber whose hardness measured with a hardness meter is 40 degrees or less, preferably 35 degrees or less.In addition, in FIG. 2, 5c is a metal roller base. Also, examples of the oil-resistant rubber forming the elastic layer 5b include EPDM, urethane, silicone, chloroprene, NBR, etc., and a system in which a conductive filler is dispersed in these to make them conductive may also be used.

(Problems to be Solved by the Invention) However, the following problems are recognized in the above-mentioned 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 5a8. However, when measuring the electrostatic chargeability of the coating film of these conductive paints, many of them have almost no charging ability even if they have the same polarity as the developer or the opposite polarity. For this reason,
Unable to consciously apply an appropriate amount of charge to the developer,
Developer layer defects such as developer spillage and non-uniformity of the adhered and carried developer layer and transportation defects are likely to occur, and it is often impossible to obtain images that are sufficient for practical use.

In the above development process, the rFJ Improvement measures are also known that focus on the ability to impart sufficient charge to the developer. For example, in the case of a developing roller that applies a solvent-based paint to the surface of the developing roller, dyes (for example, azine-based nigrosine, nigrosine bases, nigrosine derivatives, benzomethyl-hexyl A charge control agent such as an organic quaternary ammonium salt such as decyl ammonium chloride is added. However, since most of these charge control agents are insoluble or slightly soluble in solvents, they cannot be easily dispersed in paints, which makes it difficult for them to function properly and has the disadvantage that the amount added must be increased.

The present invention has been made in order to solve the above problems, and is a developing device configured to easily and always reliably apply the required amount of charge to the developer carried and conveyed on the developing roller. The purpose is to provide.

[Structure of the Invention] (Means for Solving the Problems) The present invention supplies a developer to an elastic developing roller, forms a thin layer of the developer on the outer circumferential surface of the developing roller using a regulating member, and also controls the electric charge. and a mechanism for bringing this thin layer of developer close to or in contact with an electrostatic latent image carrier to cause the developer to adhere to the electrostatic latent image held on the electrostatic latent image carrier and develop it into a visible image. In the developing device equipped with a mechanism for applying a frictional charge to the developer, a repeating unit represented by the following formula is formed in a portion of 60 to 99 mm on the surface of at least one of the developer roller regulating member and the developer supplying means that apply a frictional charge to the developer. The following formula R
s (2) (wherein, R2 is a hydrogen atom or an alkyl group, and R3
is an alkylene group, R4, R5 and R6 are alkyl groups, and the alkyl group and alkylene group have 1 to 12 carbon atoms. ) is 40 repeating units
-1! A copolymer consisting of r [ffi part, fr weight average molecular weight within the range of 3oo to 25,000, preferably 300
It is characterized by containing a copolymer containing a quaternary ammonium base in the range of 0 to 8,000. Note that from now on, the above substance will be referred to as a copolymer.

Therefore, in the above-mentioned development process, the present invention requires that a negatively charged developer is used, and that members that impart a triboelectric charge to the developer, such as the developing roller, developer layer thickness regulating member, and intermediate roller, are positively charged. This method was developed based on the fact that the developer can be sufficiently charged by charging the developer.

The copolymer according to the present invention is not only easy to handle because it is easily soluble in solvents, but also has excellent dispersibility and compatibility with paints because it is resin-based, and can be expected to be effective even when added in small amounts. There is an advantage. For example, when the copolymer according to the present invention is contained in a developer layer thickness regulating member made of silicone rubber, the desired effect can be obtained with a small amount of addition because of its excellent compatibility with the main binder.

Furthermore, a method for producing a quaternary ammonium base-containing copolymer having the above structural formula is disclosed in JP-A-03-80458.

In the present invention, by containing the copolymer in the surface of the developing roller or the developer layer thickness regulating member from 0.01 parts by weight to 80 parts by weight, preferably 10 parts by weight from the o and im parts, the developing roller This improves the surface triboelectrification properties of For example, when applying a conductive paint to a developing roller, an appropriate amount of the copolymer is dissolved in advance in a diluted solution of the conductive paint, mixed and dispersed with the conductive paint body, and this is applied to the developing roller. Dipping,
It is applied using a spray roller method, dried, and incorporated into the developing device. The thickness of the conductive layer applied here is in the range of 5 μm to 200 μm, preferably 30 μtg.
−120 μm. In addition, when improving the surface triboelectrification of the developer layer thickness regulating member, for example, when silicone rubber is used as the developer layer thickness regulating member, 0.01 ffiffi part to 40 parts by weight, preferably O , 1ffi to 10 parts by weight are added and dispersed in a kneader such as a kneader, and then vulcanized and molded to be incorporated into a developing device as a developer layer thickness regulating member.

In the developing device having the above configuration, a known non-magnetic component developer (toner) consisting of a binder resin, a coloring material, a charge control agent, a wax, an anti-caking agent, etc. is used.

For example, as the binder resin, polystyrene, poly-2
- Homopolymers of styrene and its substituted products such as chlorostyrene and polyvinyltoluene, such as styrene-P-vinyltoluene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer Coalescence, styrene-methyl acrylate copolymer, styrene-acrylic acid copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-methacrylate copolymer Ethyl acrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, styrene-alpha chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinylmethyl Ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-acrylic nitrile-indene copolymer, styrene-isoprene copolymer, styrene-maleic acid Copolymers, styrenic copolymers such as styrene-maleic acid ester copolymers, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester,
Polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, edible rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin,
Paraffin wax and the like may be used alone or as a mixture.

In addition, carbon black is used as a blue agent and charge control agent.
Various dyes and pigments are used, offset inhibitors include low molecular weight polyethylene and polypropylene, and anti-caking agents include hydrophobic silica, metal oxides, PHMA,
Examples include spherical resin particles such as Teflon and styrene.

(Function) By containing the copolymer on the surface of at least one of the members that impart the required triboelectric charge to the developer (toner), that is, the developing roller and the developer layer thickness regulating member, the effective It becomes possible to apply a strong charge to the developer, and not only can sharp line images and uniform solid images be outputted easily and reliably, but also the life of the developing device can be extended.

In order to confirm the effect of this copolymer, the amount of charge was measured using an electrostatic coating surface analyzer (manufactured by Toshiba Chemical Co., Ltd.) schematically shown in FIG. Measurement conditions were set at 25℃, 853f [all environmental atmospheres were used, spherical iron was used, the amount of pouring was t, aog per time, the time of pouring was 5 seconds, the slope was 00 degrees, and one sample was taken at a +1-1 fixed point. When measured at 5 points, the copolymer according to the present invention was not added at 80X 10
-! In contrast, the material to which the copolymer according to the present invention was added had a chargeability of 80 x 10-''C or more, which clearly shows that the chargeability is improved.

In addition, in FIG. 3, 15 is a standard iron powder inlet, 16 is an inclined plate (sample stand), 17 is a tray, 19 is an insulating plate,
20 is an electrometer and 21 is a meter connection terminal.

(Example) Next, the present invention will be explained in detail.

Example 1 0 100 g of polyurethane conductive paint SPAREX manufactured by Miractran Co., Ltd. was added with 5 liters of the above copolymer (FCA201-83 manufactured by Fujikura Kasei Co., Ltd.) in a long mixed solvent of tetrahydrofuran THP Ni-methyl ethyl ketone MfJ (1:l).
g The dissolved solvent was mixed, diluted, and dispersed.

This mixed dispersion was applied to the surface of a developing roller (urethane rubber) by a dipping method, and then dried in a dryer for 20 minutes to produce a developing roller.

The surface resistance of the developing roller thus obtained was 1XlOsΩ・
The thickness of the coating film formed was 100 μl.

The developing roller constructed as described above was substituted for the developing roller 5 of the developing device whose essential structure is shown in FIG.

As the developer 2, 92 parts by weight of polyester resin, 4 parts by weight of carbon, 2ffI parts of low molecular weight polypropylene,
11 parts of metal-containing dye 2i and 0.5ffi of external additive silica
Using a non-magnetic component developer with a volume average particle diameter of lOμ■ consisting of ffi parts, the rotation of the latent image carrier (OPC) 7 was set at a surface speed of 50 mm/s, and the rotation of the latent image carrier (OPC) 7 was set at a surface speed of 50 mm/s. The surface potential is -500V as shown in FIG.
After recording the image information with a laser as , the surface speed is 1
A developing roller 5 rotated at 0 ha/s and applied with −200 V was pressed against the latent image carrier (photoreceptor) 7 to perform the required development. This developed powder image is transferred to the transfer device 1
In No. 1, the image was transferred onto recording paper using a 6 kV DC corona discharge, and then thermally fixed.

The image after the transfer was a clear line image, a uniform solid image, and a high density image. Furthermore, the images after the life test of 50,000 sheets were clear images with no deterioration and maintaining the initial state. Furthermore, extremely good images were obtained even under high temperature and high humidity conditions.

Example 2 100 g of conductive paint Electropack manufactured by Taitai Kako Co., Ltd., 5 g of isocyanate, and 100 g of toluene were mixed with the copolymer according to the present invention (FCA201-B manufactured by Fujikura Kasei Co., Ltd.).
A solvent in which 5 g of 3) was dissolved was mixed, diluted, and dispersed. This mixed dispersion was applied to the surface of a developing roller (urethane rubber) by a dipping method, and then dried for 20 minutes in a dryer to produce a developing roller. The surface resistance of the developing roller thus obtained was 2XlO'Ω·(max.), and the thickness of the coating film formed was 100 μ−.

The developing roller constructed as described above was replaced with the developing roller 5 of the developing device whose essential structure is shown in FIG.

As developer 2, polyester resin 92ff (EiL
A latent image was formed using a non-magnetic component developer 2 with a volume average particle diameter of lOμ, which was composed of 1 part of carbon, 1 part of carbon 4ffxjli, 2 parts of low molecular weight polypropylene, 2LEiL parts of a metal-containing dye, and 0.5 parts by weight of silica as an external additive. The rotation of the carrier (OPC) 7 was set at a surface speed of 50 mm/s, the surface potential was uniformly charged to -500 V by corona discharge from the charger 9, and image information was recorded using a laser as the exposure device 8. A developing roller 5 rotated at a surface speed of 100 ml/S and applied with −200 V was pressed against the latent image carrier (photoreceptor) 7 to perform the required development. The developed powder was transferred to recording paper using a 6 kV DC corona discharge in the transfer device 11, and then thermally fixed.

The image after the transfer was a clear line image, a uniform solid image, and a high density image. Furthermore, the images after the life test of 50,000 sheets were clear images with no deterioration and maintaining the initial state. Furthermore, extremely good images were obtained even under high temperature and high humidity conditions.

Comparative Example 1 100 g of polyurethane conductive paint Subalex manufactured by Nippon Miractran Co., Ltd. was mixed with TIIF: MEK (1: l
) The mixture was diluted and dispersed in a long mixed solvent, applied to the surface of a developing roller (urethane rubber) by a dipping method, and then dried in a dryer for 20 minutes to produce a developing roller.

The surface resistance of the developing roller thus obtained was 3, lX1O'
The coating thickness was exactly 105μ.

Using the developing roller 5 configured as described above, a developing device having the same configuration as the developing device whose main part configuration is shown in FIG.
Image printing was performed under the following conditions.

The developer is a non-magnetic material with a volume average particle diameter of lOμ-, consisting of 92 parts by weight of polyester resin, 4 parts by weight of carbon, 2 parts by weight of low molecular weight polypropylene, 2 parts by weight of gold-containing dye, and 0.5 parts by weight of silica as an external additive. - Using the component-based developer 2, rotate the latent image carrier (OPC) 7 at a surface speed of 50 W.
/S, uniformly charged to a surface potential of -500V by corona discharge from the charger 9, and after recording image information with a laser as the exposure device 8, rotated at a surface speed of 100m+*/S, and The developing roller 5 to which -200 was applied was pressed against the latent image carrier (photoreceptor) 7 to perform the required development. The developed powder image was transferred to a recording paper using a 6 kV DC corona discharge in a transfer device 11, and then heat-set.

In the image after the transfer, although the line image was clear, the solid image was uneven and had poor conveyance.

Example 3 Silicone rubber 1000. 50 g of the above copolymer (PCA201-83 manufactured by Fujikura Kasei) and 150 g of aerosilic silica. and kneader for 20 minutes, 12
After kneading at 0℃, add 10g of benzoyl peroxide.
was added and vulcanized at 150°C for 20 minutes and at 200°C for 4 hours. This was molded into a metal jig to constitute a developer layer thickness regulating member.

The developer layer thickness regulating member configured above was replaced with the developer layer thickness regulating member 6 of the developing device whose main part configuration is shown in FIG. I made an image.

Developer 2 includes 92 parts by weight of polyester resin, 4 parts by weight of carbon, 2 parts by weight of low molecular weight polypropylene, 2 parts by weight of metal-containing dye, and 0.5 parts by weight of silica as an external additive.
Using a non-magnetic component developer with a volume average particle diameter of 10 μι, the rotation of the latent image carrier (OPC') 7 was set at a surface speed of 5 ha/s, and the corona discharge from the charger 9 was used. The developing roller 5 was charged to a surface potential of -500V as shown in FIG.
was pressed against the latent image carrier (photoreceptor) 7 to perform the required development. This developed powder image is transferred to the transfer device 11 at 8
The image was transferred to recording paper using kV direct current corona discharge and then thermally fixed.

The image after the transfer was a clear line image, a uniform solid image, and a high density image. Furthermore, the images after the life test of 50,000 sheets were clear images with no deterioration and maintaining the initial state. Furthermore, extremely good images were 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 using a material in which the silicone rubber did not contain the copolymer.

Using the above-mentioned developer layer thickness regulating member, a prototype developing device of the same size as the developing device shown in FIG. 1 was constructed, and images were produced under the following conditions.

As developer 2, 92 ffI m parts of polyester resin, 4 parts by weight of carbon, and 2 ffi low molecular weight polypropylene were used.
parts, 2ffI parts of metal-containing dye, and 0.5 parts of external additive silica.
Using a non-magnetic component developer with a volume average particle diameter of lOμm consisting of ffl amount parts, the rotation of the latent image carrier (OPC) 7 was set at a surface speed of 50 mm/S, and the corona discharge from the band Th device 9 was used. The surface potential is uniformly charged to -500V, and the exposure device 8
After recording image information with a laser, the surface speed is 100
(2) The developing roller 5 rotated at -/S and applied with -200 V was pressed against the latent image carrier (photoreceptor) 7 to perform the required development. This developed powder image is transferred to a transfer device 11
After transferring to recording paper using 8 kV DC corona discharge, the image was thermally fixed.

In the image after the transfer, although the line image was clear, the solid image was an image with non-uniform conveyance defects.

In addition, although the structure in which the above-mentioned copolymer is contained in either the developing roller or the developer layer thickness regulating member is shown above, it is also possible to have a structure in which both of them contain the above-mentioned copolymer. In short, the copolymer according to the present invention may be contained in at least one of the constituent members that play the role of imparting the required triboelectric charge to the developer used, for example, the developer supply roller may also be used. good. Further, the copolymer-containing region may be only the surface portion that is involved in imparting a triboelectric charge.

[Effects of the Invention] As explained above, at least the surface of the component that plays the role of imparting a triboelectric charge to the developer contains 60 to 99 ffi [m parts of the repeating unit represented by the following formula and the following formula (in the formula, R2 is a hydrogen atom or an alkyl group,
R3 is an alkylene group, and R4, Rs and R6 are alkyl groups. ) A quaternary ammonium base-containing copolymer in which the repeating unit shown by By including it, it has become possible to always and easily obtain uniform, solid, high-density images with clear development characteristics. Moreover, it can be said that it brings about many practical advantages, such as being able to maintain the above-mentioned required functions for a long period of time, and being able to cope with changes in the properties of the developer due to the environment.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the configuration of the main parts of the developing device, Figure 2 is a partially cutaway perspective view showing the configuration of the developing roller, and Figure 3 is the principle of an electrostatic coating surface analysis device for measuring the amount of charge. It is a diagram. 1...Developer container 2...Developer 3...Stirrer 4...Developer supply Roller 5a...
Developing roller 5b... Conductive layer 6... Elastic layer 7... Latent image holder 8...・Exposure unit 9...Charger 0...Cleaning unit...
...Transfer device 2...Recovery blade 3...
...Protection resistor 4...DC power supply

Claims (1)

[Scope of Claims] A developing roller having elasticity, a developer supply means for supplying a developer to the outer circumferential surface of the developing roller, and a thin layer of the developer supplied with an end close to the outer circumferential surface of the developing roller. A developing device comprising: a regulating member that applies an electric charge at the same time that the developer layer is thinned; and an electrostatic latent image holder that develops an electrostatic latent image held in close proximity to or in contact with the thinned developer layer into a visible image. A developing roller that applies a triboelectric charge to the developer;
The surface of at least one of the regulating member and the developer supplying means has a repeating unit represented by the following formula ▲ There is a mathematical formula, chemical formula, table, etc. ▼ (1) (In the formula, R_1 is a hydrogen atom or an alkyl group) 60 to 99 parts by weight and the following formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (2) (In the formula, R_2 is a hydrogen atom or an alkyl group, and R
_3 is an alkylene group, R_4, R_5 and R_
6 is an alkyl group, and the alkyl group and alkylene group have 1 to 12 carbon atoms. ) A developing device comprising a quaternary ammonium base-containing copolymer containing 40 to 1 part by weight of repeating units represented by the following formula and having a weight average molecular weight in the range of 300 to 25,000.