JP2003270926A - Developing roller, developing device, and electrophotographic process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress image defects or fog due to deformation of a roller and to obtain a preferable image even after the roller is used for a long period of time in an electrophotographic method. <P>SOLUTION: The developing roller comprises an axial core body and two or more layers disposed on the peripheral face of the core, and one layer in the layers except for the surface layer is an elastic layer. The Asker-C hardness A (degree) of the roller having the surface layer, the Asker-C hardness B (degree) of the roller having only the elastic layer, and the thickness C (μm) of the surface layer satisfy 30≤A≤70, |A-B|≤15 and |A-B|×C≤450. The micro-hardness of the roller having the surface layer is 20 to 60 (degree). In the developing roller having the axial core body and two or more layers disposed on the peripheral face of the core body, the surface layer contains ≥25 mass% of polyether polyols prepared by extending chains of a source polyol by chiefly using diisocyanate. A developing device and an electrophotographic process cartridge equipped with the developing roller are also disclosed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is incorporated in an electrophotographic image forming apparatus such as a copying machine, a printer or a facsimile receiver, and is a developing roller for developing a latent image on a photoreceptor with a developer. And a developing device. The present invention also relates to an electrophotographic process cartridge that includes a developing device and is detachably attached to the image forming apparatus.

[0002]

2. Description of the Related Art In recent electrophotographic apparatuses, a one-component developing device tends to be used as the main body becomes smaller. The one-component developing method using a one-component developer gives an electric charge to the developer particles by friction between the developer regulating member and the developer particles and friction between the developing roller and the developer particles, and at the same time, the developer is applied on the developing roller. It is a method of applying thinly and conveying it to a developing area where the developing roller and the latent image carrier face each other, developing the electrostatic latent image on the latent image carrier to visualize it as a developer image.

Unlike the two-component developing method, the one-component developing method does not require carrier particles such as glass beads, iron powder, and ferrite, so that the developing apparatus itself can be made compact and lightweight. Furthermore, in the two-component development method, it is necessary to keep the developer concentration in the developer constant, so a device that detects the developer concentration and replenishes the required amount of developer is required. Invite. Also in this respect, the one-component developing method is advantageous for downsizing and weight saving.

The one-component developing method is roughly classified into a magnetic one-component developing method using a magnetic developer containing a magnetic material in a developer and a non-magnetic one-component developing method not using a magnetic material. A full-color printer uses a non-magnetic one-component developing method in which a color developer can be used.

In such a non-magnetic one-component developing method, the developer is supplied onto the developing roller by the elastic roller contacting the developing roller, and then the developer is applied thinly on the developing roller by the developer regulating member. An electric charge is given to the developer particles by friction with the developer regulating member and friction with the developing roller. Further, the developer charged positively or negatively by frictional contact is electrostatically attached to the surface of the latent image carrier (photosensitive drum). Therefore, the developing roller is composed of a roller having elasticity and conductivity. As a conductive material for forming the developing roller, conventionally, a rubber material such as silicone rubber, acrylonitrile butadiene rubber, urethane rubber, or silicone-modified ethylene propylene rubber has been used as a base, and carbon black or metal has been used to impart conductivity to the base. A conductive rubber material containing a conductive material such as powder is used.

[0006]

As a characteristic of the above-mentioned developing roller, it is necessary to secure a constant contact area, and rubber is required to have low hardness and low compression set. However, when the hardness is lowered, oil may ooze out, and the photosensitive drum may be contaminated at the pressure contact portion with the photosensitive drum.

In order to solve such a problem, for example,
A developing roller having a two-layer structure in which a conductive elastic layer is formed along the outer peripheral surface of the mandrel and a surface layer is formed on the outer peripheral surface thereof to prevent contamination of the photosensitive drum and adhesion of the developer is used. ing. This surface layer has good releasability so that the developer can be transferred to the electrostatic latent image formed on the surface of the photosensitive drum, and has good abrasion resistance that can withstand contact with the photosensitive drum or blade. It is made of a rubber material, a resin material, or the like having good properties.

The material for forming the surface layer of the developing roller is
A material having a high hardness is generally used in order to increase the crosslink density of a rubber material or the like so as to sufficiently exert the effects such as releasability and abrasion resistance. Therefore, especially when the roller is pressed against the drum at a time other than the time of operation such as after printing is stopped, when the printing is restarted, the developing roller starts to rotate and the deformation caused in the contact portion with the layer forming blade is caused by the deformation. Striped stripes may occur in the image of the deformed portion until returning, and defects may occur in the image. In addition, the roller is pressed against the drum except when it is in operation, and stress concentration occurs in both the elastic layer and the surface layer. Due to this stress concentration, image defects may occur due to partial resistance change due to compositional deformation of the surface layer, and peeling of adhesion between the elastic layer and the surface layer may occur. Further, increasing the hardness of the surface layer may cause stress in the developer, which may cause image defects due to deterioration of the developer. As a countermeasure in this case, silicone rubber or urethane resin having excellent compression set characteristics has been used as the elastic layer or the surface layer.

However, with the improvement in image quality, it is becoming impossible to deal with them only by using these materials having excellent compression set characteristics.

On the other hand, when the developer regulating member or the photosensitive drum comes into contact with the developing roller via the developer, fog may occur due to insufficient charge imparting property to the developer.
Although various factors relating to the charge imparting property to the developer have been considered, generally, the higher the hardness of the outermost surface layer (the layer provided on the outermost side of the roller), the more advantageous the charge imparting property to the developer is. It is considered.

Therefore, the present invention has improved the above points and optimized the construction of the developing roller to provide a developing roller having a low hardness and a low compression set, and the outermost surface layer having a low elastic modulus. The purpose is to provide a developing roller with less fog by using a surface layer material with good fog performance,
This makes it possible to obtain a good image.

Still another object of the present invention is to provide a developing device and an electrophotographic process cartridge using such a developing roller which can form an excellent image for a long period of time.

[0013]

As a first form of a developing roller of the present invention, a shaft core, an elastic layer provided on the outer peripheral surface of the shaft core, and an outer peripheral surface of the elastic layer are provided. In the developing roller including the surface layer, the roller having the surface layer has an Asker-C hardness of A (degrees), the roller having only the elastic layer has an Asker-C hardness of B (degrees), and the surface layer has a thickness (μm).
Let C be 30 ≦ A ≦ 70, and | AB |
≦ 15, | A−B | × C ≦ 450, and the roller having a surface layer has a micro hardness of 20 to 20.
There is provided a developing roller characterized by being 60 (degrees).

In the developing roller of the first aspect, the developing roller may be a developing roller having one elastic layer and one surface layer.

It is also preferred that the surface layer contains an electronically conductive agent.

It is also preferable that the elastic layer contains silicone rubber.

Further, it is preferable that the elastic layer contains 5 to 15 parts by mass of an electronic conductive type conductive agent with respect to the silicone rubber.

It is also preferable that the silicone rubber is a silicone rubber obtained by crosslinking silicone with a curing agent having a siloxane skeleton.

It is also preferable that the surface layer contains a urethane resin.

It is also preferable that the outermost surface layer, which is the outermost layer of the surface layer, contains 25% by mass or more of a polyether-based polyol, which is obtained by chain-extending the raw material polyol mainly with diisocyanate.

As the second mode of the developing roller of the present invention,
In a developing roller having a mandrel and two or more layers provided on the outer peripheral surface of the mandrel, the outermost surface layer, which is the outermost layer, is obtained by chain-extending a raw polyol mainly with diisocyanate. And a polyether-based polyol which is 25% by mass or more.

It is preferable that the starting polyol is one or more selected from polypropylene glycol and polytetramethylene ether glycol.

It is particularly preferable that the starting polyol is polytetramethylene ether glycol.

The weight average molecular weight of the raw material polyol is 5
It is also preferably in the range of 00 to 5000.

It is also preferable that the chain-extended polyether polyol has a weight average molecular weight of 5,000 to 80,000.

It is also preferable that the hydroxyl value of the chain-extended polyether polyol is in the range of 15 to 160 KOHmg / g.

It is also preferable that the film thickness of the surface layer is 5 to 100 μm.

According to the present invention, a container containing a developer,
A developing roller for carrying a developer, wherein a developing device for visualizing a latent image as a developer image by applying the developer to a latent image carrier carrying a latent image, A developing device is provided which is the above-mentioned developing roller.

In this developing device, the developing roller is preferably used in contact with the latent image carrier.

Further, according to the present invention, a latent image is formed by applying a developer to a latent image carrier having a container for containing a developer and a developing roller for carrying the developer. A developing device for visualizing a developer image includes a latent image carrier that carries a latent image, a charging member that charges the latent image carrier, a cleaning member that cleans the latent image carrier, and the latent image carrier. An electrophotographic process cartridge, which is integrally held with at least one of transfer members for transferring the above developer image to a recording medium, wherein the developing roller is the above developing roller. A cartridge is provided.

[0031]

DETAILED DESCRIPTION OF THE INVENTION The present inventors have investigated the cause of the appearance of streaks in the image of the developer regulating member or the photosensitive drum, even if a material having excellent compression set characteristics is used. It was found that the compression set characteristics are impaired due to the occurrence of stress concentration and the elastic recovery of the developing roller is delayed. By using the developing roller as in the first embodiment, the stress concentration generated in the elastic layer and the surface layer can be suppressed, the elastic recovery of the roller is increased, the compression set is excellent, and the image defect does not occur. I found that. That is, a non-magnetic one-component developer is carried on the surface of the developing roller to form a thin layer of the developer, and this is brought into contact with a latent image carrier such as a photoconductor to electrostatically charge the latent image carrier. It has been found that by developing the latent image, the developing roller is brought into close contact with the latent image holding member and a high quality image can be obtained.

Further, 25% by mass of polyether polyol obtained by chain-extending a raw material polyol such as PTMEG (polytetramethylene ether glycol) mainly with diisocyanate in the surface layer provided in the outermost layer like the developing roller of the second embodiment. By using the above-described materials, a stable image with less fog can be obtained, and this stable image can be maintained.

When the polyether-based polyol is a polyol obtained by chain-extending the starting polyol mainly by using diisocyanate, the urethane bond contained in the polyether-based polyol contributes as a cross-linking point to facilitate rubber elasticity. A stable image with less fog can be obtained including compatibility with other performances such as setting property.

When the main component of the raw material polyol is at least one of PPG (polypropylene glycol) and PTMEG (polytetramethylene ether glycol), a material having a relatively low glass transition point is easily obtained and the set Compatibility with other performances is easy, and stable images with less fog can be obtained. Further, when the main component of the raw material polyol is PTMEG (polytetramethylene ether glycol), it can be a more flexible material due to the difference in the repeating units of its main chain, so that it may have other properties such as settability. The compatibility is easy, and a stable image with less fog is obtained, and the effect is remarkable.

Further, by using the constitution of the developing roller of the first embodiment and the material of the outermost surface layer of the second embodiment in combination, it is possible to improve the recoverability of the developing roller and reduce the fog at the same time. It was found that a high quality image can be obtained.

1 and 2 show a perspective view and a sectional view of an example of the developing port la of the present invention. Development port 1
The elastic layer 12 is fixed to the outer peripheral surface of the cylindrical or hollow cylindrical conductive mandrel 11, and the surface layer 13 is laminated on the outer peripheral surface of the elastic layer 12.

The elastic layer is a layer having a thickness of, for example, about several millimeters, which is provided to give elasticity to the developing roller in order to secure a proper contact area when pressed against the developer regulating member and the photosensitive drum. In some cases, the layer may be composed of a plurality of layers, but in the present invention, a plurality of layers may be used as long as the layer is provided for the purpose of imparting elasticity to the developing roller in order to secure an appropriate contact area. Is included in the elastic layer. The roller having only the elastic layer means a roller having only the elastic layer as described above provided on the mandrel (no surface layer).

The surface layer is, for example, for controlling the surface of the developing roller such as the surface shape (roughness) for improving the developer transportability, and for preventing the low molecular weight component of the elastic layer from seeping out. In some cases, a plurality of layers are provided in order to satisfy this purpose. However, in the present invention, even if the surface layer is a plurality of layers, all layers are included in the surface layer. Depending on the case, a layer for adjusting resistance or an adhesive layer for adhering the elastic layer and the surface layer may be provided with a thickness of, for example, 100 μm or less. In the present invention, such a resistance adjusting layer or adhesive layer is also provided on the surface. Included in layers. The roller provided with the surface layer means a completed developing roller, and this expression is used for comparison with the roller having only the elastic layer.

<Shaft Core> The shaft core of the conductive roller can be applied to the present invention as long as it functions as an electrode and a supporting member of the conductive member. The material is, for example, a metal or alloy such as aluminum, copper alloy, or stainless steel, iron plated with chromium or nickel, or a conductive material such as synthetic resin. The outer diameter of the mandrel is, for example, in the range of 4 to 10 mm from the viewpoint of the amount of bending of the mandrel.

In order to bond the mandrel and the elastic layer formed on the peripheral surface of the mandrel, a primer or the like can be appropriately applied to the mandrel, and a commonly used known primer can be used.
For example, a silane coupling type primer can be used.

<Elastic Layer> As the rubber material used as the elastic layer of the developing roller of the first embodiment, from the viewpoint that a highly accurate developing roller can be produced due to the uniformity of reaction, or
Silicone rubber is preferably contained from the viewpoints of excellent compression set and setting performance. Specific examples thereof include silicone rubbers such as dimethyl silicone rubber, methylphenyl silicone rubber, methylvinyl silicone rubber, and methylphenylvinyl silicone rubber. Or
Ethylene-propylene-diene copolymer rubber (EPD
M), acrylonitrile-butadiene rubber (NBR),
Chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SB
R), fluororubber, epichlorohydrin rubber, hydride of NBR, other sulfide rubber, and silicone rubber such as rubber in which the above-mentioned silicone rubber is mixed. In this case, it is desirable to mix another rubber to the extent that the compression set characteristics of the silicone rubber are not impaired. Further, another rubber can be appropriately used as the elastic layer.

The silicone rubber is preferably a silicone rubber having a siloxane skeleton from the viewpoint that the backbone of the rubber is preferably a silicone rubber having only a silicon-oxygen bond in order to improve the compression set characteristics. It is preferably a silicone rubber crosslinked by.

For example, rubber obtained by curing liquid silicone rubber as described below can be used for the elastic layer.
As a liquid silicone rubber, it has excellent processability, good dimensional stability due to the absence of by-products associated with the curing reaction, stable physical properties after curing, etc.
Addition reaction cross-linkable liquid silicone rubber is preferred.

The liquid silicone rubber is, for example, a composition containing the organopolysiloxane represented by the formula 1 and the organohydrogenpolysiloxane represented by the formula 2, and further containing a catalyst and other additives as appropriate. it can.

[0045]

[Chemical 1]

Organopolysiloxane is a base polymer used as a raw material for silicone rubber. From the viewpoint of processing characteristics and characteristics of the obtained silicone rubber composition, the viscosity of the organopolysiloxane is preferably 10 Pa · s or more as the lower limit, more preferably 50 Pa · s or more, and 300 Pa · s or less as the upper limit. Preferably 250 Pa · s
The following is more preferable. The molecular weight is not particularly limited, but in order to obtain the above viscosity, it is preferably 100,000 or more and 1,000,000 or less, and the average molecular weight is preferably 400,000 or more and 700,000 or less.

The alkenyl group of the organopolysiloxane is a site which reacts with the active hydrogen of the organohydrogenpolysiloxane to form a cross-linking point, and the kind thereof is not particularly limited, but the reactivity with the active hydrogen is high, etc. For this reason, at least one of a vinyl group and an allyl group is preferable, and a vinyl group is particularly preferable.

[0048]

[Chemical 2]

The organohydrogenpolysiloxane functions as a cross-linking agent in the addition reaction in the curing step. The number of silicon atom-bonded hydrogen atoms in one molecule is 2 or more, and the curing reaction is optimally performed. Therefore, three or more polymers are preferred. There is no particular limitation on the molecular weight of the polyorganohydrogensiloxane, and it is, for example, 1000 to 10000. Relatively low molecular weight (1000 to 5000) for proper curing reaction
Is preferred.

The elastic layer of the developing roller of the second embodiment has hardness and electric property so that the conductive member can press the surface of the charged body with a proper nip width or nip pressure to uniformly charge the surface of the charged body. It is preferable to adjust the resistance value.
This elastic layer is formed of a molded body of rubber material.

As the raw material rubber, various kinds of rubber conventionally used for conductive rubber rollers can be used. Specifically, silicone rubber, ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (C
R), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluororubber, epichlorohydrin rubber, hydride of NBR, other sulfurized rubber,
Rubber such as urethane rubber may be used alone or in combination of two or more.

Examples of the cross-linking agent include di-t-butyl peroxide and 2,5-dimethyl-2,5-di (t-
Butyl peroxy) hexane, dicumyl peroxide, t-butyl peroxybenzoate, P-chlorobenzoyl peroxide and the like.

The following description of the elastic layer relates to the developing rollers of the first and second forms.

The rubber material may contain various additives such as a conductive agent and a non-conductive filler, a cross-linking agent, a catalyst, a dispersion accelerator, etc., which are added if necessary.

As the conductive agent, an electronic conductive type conductive material is preferable. Examples of the electronic conductive material include various conductive metals or alloys such as carbon black, graphite, aluminum, copper, tin, and stainless steel, tin oxide, zinc oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solution, and oxidation. Various conductive metal oxides such as tin indium oxide solid solution and fine powders of insulating substances coated with these conductive materials can be used. Among these, carbon black is preferable because it is relatively easy to obtain and good chargeability can be obtained.

These particles are used by being dispersed in a rubber material, and as a dispersing means, a roll kneader, a Banbury mixer, a ball mill, a sand grinder, a paint shaker or the like may be appropriately used.

In addition, a conductive polymer compound may be added as another conductive agent. For example, as the host polymer, polyacetylene, poly (p-phenylene), polypyrrole, polythiophenine, poly (p-phenylene oxide), poly (p-phenylene sulfide), poly (p-phenylene vinylene), poly (2,6-dimethyl) Phenylene oxide), poly (bisphenol A carbonate), polyvinylcarbazole, polydiacetylene, poly (N-methyl-4-vinylpyridine) polyaniline, polyquinoline, poly (phenylene ether sulfone), etc. are used, and ASF ₅ , I ₂ , Br ₂ , S
O ₃ , NaClO ₄ , KClO ₄ , FeCl ₃ , F, Br,
Cl, I, Kr, etc. ions, Li, TCNQ (7,
A material doped with (7,8,8-tetracyanoquinodimethane) or the like is used.

The compounding amount of the conductive agent may be appropriately determined so that the elastic layer has a desired resistance value. The resistance value of the elastic layer is 2
It is preferably in the range of 10 ³ to 10 ¹⁰ Ω when a DC voltage of 00 V is applied. For example, when silicone rubber is used as the rubber material and carbon black is used as the electronic conductive type conductive agent, it is preferable to add 5 to 100 parts by mass to 100 parts by mass of the silicone rubber, from the viewpoint of compression set characteristics. It is more preferable to add 15 to 15 parts by mass. The resistance value of the conductive roller is set such that the conductive roller is pressed against the metal drum by applying a load of 500 g to both ends of the shaft body, the rotation speed of the roller is rotated at 60 rpm, and the shaft of the metal drum and the conductive roller is rotated. The resistance value can be calculated by applying a voltage of 200 V to the body and measuring the current value flowing through the elastic roller.

As a non-conductive filler, an inorganic filler can be added as a reinforcing agent. As the inorganic filler, for example, diatomaceous earth, quartz powder, silica (dry silica,
Wet silica etc.), titanium oxide, zinc oxide, aluminosilicate, calcium carbonate and the like. There is no particular limitation on silica, and conventionally known silica can be widely used. Examples thereof include silicic acid anhydride by a dry method, hydrous silicic acid by a wet method, and synthetic silicate.

From the viewpoint of low hardness and low compressive strain, the amount of the inorganic filler added is, for example, 10 parts from the viewpoint of preventing thermal deterioration and hardness reduction with respect to 100 parts by mass of the silicone rubber.
It is preferably not less than 100 parts by mass, and more preferably not more than 100 parts by mass from the viewpoint of suppressing compression set. 20 more
More preferably, it is 80 parts by mass.

The thickness of the elastic layer is preferably 0.5 to 6.0 mm, more preferably 1.0 to 5.0 mm, from the viewpoint of ensuring a uniform nip width and charging performance. preferable.

<Surface Layer> Normally, the prevention of contamination of the photosensitive drum,
Alternatively, a surface layer can be provided to control the surface of the developing roller. The surface layer can contain a conductive agent and an additive added as needed.

First, the surface layer of the developing roller of the first embodiment will be described.

From the viewpoint of compression set, the surface layer preferably contains a urethane resin. Urethane resin is used as the material of the surface layer base, and other components can be added to the extent that the compression set characteristics of the urethane resin are not impaired.

It is effective to utilize the flexibility, deformation recovery and abrasion resistance of the urethane resin. From this viewpoint, it is preferable that the surface layer contains as much resin component as possible, but the conductivity and The content of the urethane resin in the surface layer is usually preferably 40 to 90% by mass, because a conductive agent and various fillers are appropriately mixed in order to form a reinforcing property or a physical shape. When the content is 40% by mass or more, the effect of excellent physical properties of the urethane resin can be satisfactorily obtained, and when the content is 90% by mass or less, it is acceptable to contain other components to the extent that they can effectively function.

Examples of the polyol compound used in the urethane resin include well-known polyurethane polyols such as polyethylene glycol, tetramethylene glycol polyethylene diadipate, polyethylene butylene adipate, poly-ε-caprolactone diol, polycarbonate polyol and polypropylene glycol.

As the isocyanate compound, diisocyanates such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI) and hexamethylene diisocyanate (HDI), and their burette modified products, isocyanurate modified products, urethane modified products and the like can be used. It can be preferably used. More preferred isocyanate compounds are HDI and its buret modified product, isocyanurate modified product, urethane modified product, polymeric MDI, urethane modified polymeric MDI and the like. The longer the molecular chain of the isocyanate compound, the more flexible the polyurethane surface layer can be formed.

Another resin may be appropriately used as the surface layer. Specifically, polymethylmethacrylate resin,
Fluorine resin, vinylidene fluoride resin, silicone resin,
There are epoxy resin, polyamide resin, polystyrene resin, acrylic resin, phenol resin, melamine resin, polyolefin resin, polyethylene resin and the like.

Next, the surface layer of the developing roller of the second embodiment will be described.

From the viewpoint of reducing fog, the surface layer is
It is preferable to contain 25 mass% or more of a polyether-based polyol, which is obtained by chain-extending the raw material polyol mainly using diisocyanate. When crosslinking is performed by including the chain-extended polyol component, isocyanates as a crosslinking component are essential. Conversely, a non-crosslinked urethane resin (only a polyol component) may be used without adding a crosslinking component. Other components are not particularly limited, but polyamide resin, urethane resin, urea resin and the like are preferably used from the viewpoints of self-film reinforcing property, toner charging property and the like. In the case of blending a urethane resin containing a polyether polyol with another component, it is preferable that the other component is also a urethane resin from the viewpoint of compatibility and the like.

Examples of the urethane resin include those obtained by a method of crosslinking a prepolymer and those obtained by a method of reacting a polyol with polyisocyanate by a one-shot method. The preferred method is a method of crosslinking reaction of the former prepolymer.

In this case, the polyhydroxyl compound used to obtain the polyurethane is a polyol used in the production of general flexible polyurethane foams and urethane elastomers, for example, polyether polyol having a polyhydroxyl group at the end, polyester polyol, and In addition to polyether polyester polyols which are copolymers of both, polyolefin polyols such as polybutadiene polyols and polyisoprene polyols, and so-called polymer polyols obtained by polymerizing ethylenically unsaturated monomers in polyols are generally used. Various polyols can be used.

Examples of the diisocyanate as a main component for chain-extending the raw material polyol include diisocyanates such as isophorone diisocyanate (IPDI) and 4,4′-diphenylmethane diisocyanate (MDI). When the raw material polyol is chain-extended, not only the above-mentioned diisocyanate but also a polyfunctional isocyanate obtained by TMP (trimethylolpropane) modification or isocyanurate modification, that is, a trifunctionalized or more functionalized isocyanate is used. By appropriately adding, the chain-extended polyol can have an appropriate degree of branching.

Diisocyanate as main component (bifunctional)
The type and ratio of the trifunctional or higher functional component (not necessarily isocyanate) and the ratio thereof may be appropriately selected according to the desired chain-extended polyol, but from the viewpoint of flexibility and strength, the trifunctional or higher functional component. Is preferably about 20 mol% or less based on the sum of the diisocyanate (bifunctional) and the trifunctional or higher functional component. In other words, the chain extension in the present invention can include simple chain extension with the above-mentioned diisocyanate (bifunctional) and chain extension involving branching with a tri- or higher functional component, and the former is the main reaction. Of the components used for chain extension, diisocyanate, which is a bifunctional component, is mainly used, preferably 80 mol% or more.

Examples of the raw material polyol include polyether polyols such as polyethylene glycol (PEG), polypropylene glycol (PPG) and polytetramethylene ether glycol (PTMEG).

For example, the raw material polyol such as PTMEG used in the present invention has a weight average molecular weight of 500 to 5,0.
00, preferably a weight average molecular weight of 800 to 4,50
0, and more preferably 1,000 to 3,500.
When the weight average molecular weight is less than 500, it is disadvantageous in that the flexibility and elongation required for the surface layer tend to be difficult to obtain. Further, when the weight average molecular weight exceeds 5,000, the molecular weight distribution is wide and it is disadvantageous in that it tends to be difficult to appropriately maintain the breaking strength and elongation of the surface layer.

The weight average molecular weight is GPC (gel permeation
Of chromatogram by solution chromatography)
The offspring amount is measured under the following conditions. That is, heat chill at 40 ° C
Stabilize the column in the chamber and cover at this temperature.
THF (tetrahydrofuran) as a solvent in the ram every minute
Flow at a flow rate of 1 ml to obtain a sample concentration of 0.05 to 0.6
The THF sample solution of the resin adjusted to the weight% is 50 to 200
Inject μl and measure. When measuring the molecular weight of a sample
Is the molecular weight distribution of the sample
The logarithmic value and the count of the calibration curve prepared with the Ren standard sample.
It is calculated from the relationship with the number. Standard police for creating calibration curve
As the Tiren sample, for example, PressureChe
medical Co. Made by Toyo Soda Co., Ltd.
The amount is 6 × 10² , 2.1 x 10³ 4 x 10³ 1.
75 x 10^Four 5.1 × 10^Four , 1.1 x 10^Five 3.
9 x 10^Five , 8.6 × 10^Five 2 x 10⁶ 4.48x
10 ⁶ Standard poly with at least 10 points
Suitably a styrene sample is used. Also, the detector
An RI (refractive index) detector is used. In addition, as a column,
It is preferable to combine multiple commercially available polyethylene gel columns.
, For example, μ-styrage manufactured by waters
l 500, 103, 104 and 105 combinations and
Shoden KF-80M and KF-8 made by WEDenko
Combination of 01, 803, 804 and 805, KA-80
A combination of 2, 803, 804, 805, or made by Toyo Soda
TSKgel G1000H, G2000H, G25
00H, G3000H, G4000H, G5000H,
A combination of G6000H, G7000H and GMH is preferred.
Good

Further, these raw material polyols may be produced by any method. For example, PT
MEG is manufactured by using telopoly acid as a catalyst and THF.
Examples thereof include a method of ring-opening polymerization of (tetrahydrofuran), a method of hydrolyzing an end group after ring-opening polymerization of THF using fluorosulfonic acid as a catalyst, and the like.

The weight average molecular weight of the chain-extended polyether polyol used in the present invention is preferably 5,
000-80,000, more preferably 5,000-6
5,000, more preferably 5,000 to 50,000
It is 0. When the weight average molecular weight is 5,000 or more,
The rubber elasticity of the surface layer can be improved to 80,00.
When it is 0 or less, the surface layer can be easily and stably formed. Further, when it is 50,000 or less, the solubility in a solvent is good and the solution is easily handled,
Particularly preferred.

The hydroxyl value of the chain-extended polyether polyol used in the present invention is preferably 15-16.
0 KOH mg / g, more preferably 15 to 120 KOH
mg / g, more preferably 15-80 KOH mg / g
Is. When the hydroxyl value is 15 KOHmg / g or more,
Good reinforcement by cross-linking, 160 KOHmg / g
The following is preferable because it is easy to increase the weight average molecular weight of the chain-extended polyether polyol.

The hydroxyl value is determined according to JIS K0070 "Testing method for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products".

As described above, it is preferable that the surface layer 13 contains 25% by mass or more of the polyether polyol component, more preferably 30% by mass or more, further preferably 35% by mass or more.

When the content of the polyether-based polyol component is 25% by mass or more, the effect of reducing fog is satisfactorily exhibited. From the viewpoint of suppressing fog, the polyether-based component is preferably contained in the surface layer as much as possible, but isocyanates and crosslinking agents to be the crosslinking component,
Considering the proper blending of various fillers, the content of the polyether polyol component in the surface layer is preferably 85% by mass or less.

The chain-extended polyester polyol is
Alone or with other polyols blended,
Furthermore, it can be crosslinked with isocyanates.

As the isocyanate compound used therefor, the same ones as those used for the surface layer according to the first embodiment can be used. Polyisocyanate used for the production of general flexible polyurethane foams and urethane elastomers, that is, triisocyanate Diisocyanate (TDI), crude TDI, isophorone diisocyanate (IPDI) 4,
4'-diphenylmethane diisocyanate (MDI),
Crude MDI, C2-C18 aliphatic polyisocyanate, C4-C15 alicyclic polyisocyanate and mixtures and modified products of these polyisocyanates, for example, prepolymers obtained by partially reacting with polyols, etc. Is used.

For the surface layer, one or more kinds of urethane resins and other modified resins may be mixed and used, and by appropriately selecting and using them according to the developing system, the developing system It is possible to obtain a toner charge amount suitable for.

As the conductive agent that can be contained in the surface layer, the above-mentioned conductive agent used in the elastic layer, preferably an electronic conductive type conductive agent can be used in the surface layer. Also for the surface layer, carbon black is preferable because it is easily available and good chargeability can be obtained. Further, in order to include the conductive agent in the surface layer, the dispersing means described for the elastic layer may be appropriately used.

The amount of the conductive agent contained in the surface layer is, for example, in the case of using carbon black, the resin component 10
It is preferably 5 parts by mass or more with respect to 0 parts by mass from the viewpoint of the conductivity of the surface layer, and 100 parts by mass or less from the viewpoint of suppressing the hardness of the surface layer from increasing and ensuring the followability to the elastic layer. preferable. From the viewpoint of increasing the content ratio of the polyether-based polyol, which is a chain-extended mainly using diisocyanate, 5 to 60 parts by mass is more preferable.

As a means for applying the surface layer 13 to the surface of the elastic layer 12, a method of applying a resin solution to the elastic layer 12 is effectively adopted. The concentration of the resin component in this resin solution is not particularly limited and may be appropriately adjusted depending on the required film thickness. However, from the dispersibility and stability of various additives such as a conductive agent in the solution, the concentration of the resin component is It is preferably 8% or more. The solvent for adjusting the resin solution may be any as long as it can dissolve the resin,
For example, lower alcohols such as methanol, ethanol and isopropanol, ketones such as methyl ethyl ketone, cyclohexane, toluene and xylene are preferably used. In particular, it is preferable to use a mixed solvent of these in order to obtain a good film-forming property in the drying step after coating.

When the resin solution is prepared and used as described above, it is preferable that the above-mentioned conductive agent has a relatively small density and is hard to settle, and carbon black or the like is easily used.
A dispersant may be added to the resin solution for the purpose of further improving the dispersion stability of various additives such as a conductive agent.

As a coating method, a spray method, a roll coater method, a dipping method or the like can be used after the resin solution is prepared. For example, as a method by dipping, a method in which the mouthpiece having the elastic layer 12 formed thereon is immersed in a resin solution having the above concentration at room temperature for 5 seconds to 3 minutes, preferably 10 seconds to 30 seconds and then pulled up and dried is adopted. can do. When the spray method is adopted, the resin concentration in the resin solution can be set higher than that in the dipping method. For example, the solid content concentration in the solution is 30.
It is also possible to use the one adjusted to a mass% or more. In either case, the optimum resin concentration, coating method, and coating conditions may be set so that the desired film thickness can be obtained.

The thickness of the surface layer is preferably in the range of 5 to 300 μm, more preferably in the range of 10 to 100 μm in consideration of the recoverability and durability (wear resistance) of the developing roller. The thickness of the surface layer can be determined by cutting a part of the roller and observing with a microscope.

<Physical Properties of Elastic Layer and Surface Layer> The developing roller according to the first embodiment of the present invention satisfies the following conditions.

(1) Asker of roller provided with surface layer
Asker-C hardness of a roller having a surface layer on an elastic layer, in which 30 ≦ A ≦ 70 when −C hardness is A, prevents occurrence of streaks on the image due to large compression set. From the viewpoint, 30 degrees or more is preferable, and from the viewpoint of uniformity of the nip width with the photosensitive drum, 70 degrees or less is preferable.

The "Asker-C hardness" means the Aske in accordance with the Japan Rubber Association standard SRIS0101.
The hardness of the roller measured by using an r-C type spring hardness meter (manufactured by Kobunshi Keiki Co., Ltd.), and allowed to stand for 5 hours or more in an environment of normal temperature and normal humidity (23 ° C, 55% RH). The hardness meter is brought into contact with the center of the roller with a force of 1 kg, and the measured value is obtained 30 seconds after the contact.

(2) Asker-of the roller having only the elastic layer
When C hardness is B, | AB | ≦ 15.

By setting | AB | ≦ 15, it is possible to prevent stress concentration in the elastic layer and the surface layer when they are pressed against the photosensitive drum or the developer regulating blade.

(3) When the thickness (μm) of the surface layer is C, | AB | × C ≦ 450. ｜ AB ｜ × C
By setting the value of to 450 or less, the photosensitive drum or
When the image is brought out in such a state that it is pressed against the blade for a long period of time and is released from the pressed state, it is possible to prevent the appearance of light and shade in the vicinity of the part pressed against the roller on the image.

(4) Regarding the roller provided with the surface layer, the micro hardness of the roller is 20 to 60 degrees.

That is, from the viewpoint of making the developer layer uniform after passing through the developer regulating member, it is preferable that the microhardness is 20 degrees or more, and image defects due to the occurrence of stress due to the high hardness of the surface of the surface layer occur. From the viewpoint of prevention, a micro hardness of 60
It is preferably not more than a degree. The microhardness of the roller provided with the surface layer was measured by a micro rubber hardness tester MD-1 type, Ty.
Using peA (manufactured by Kobunshi Keiki Co., Ltd.) at room temperature and normal humidity (23 ° C,
The center part of the roller is measured with respect to the roller left in the environment of 55% RH for 5 hours or more.

[Method of Manufacturing Developing Roller] Next, an example of the method of manufacturing the developing roller of the present invention will be described.

First, a primer is applied to the outer periphery of the mandrel by a spray method, a dipping method, or the like. Then, it is dried and baked in a baking oven heated by hot air, infrared rays or the like to form an adhesive layer on the outer periphery of the mandrel. The thickness of the adhesive layer is the viscosity of the silane coupling adhesive (dilution with solvent, addition of diluent)
Adjust by. The baking conditions are preferably 100 to 2
00 ° C, more preferably 120 to 170 ° C, 15 to 6
It is preferable to hold for 0 minutes. If the temperature is lower than 100 ° C., it is disadvantageous in that the baking tends to be insufficient and good adhesion tends to be difficult to obtain. Also, the temperature is 2
If the temperature exceeds 00 ° C, the adhesive decomposes, and in this case also, it tends to be difficult to obtain good adhesion, which is disadvantageous.

Next, the mandrel provided with the adhesive layer is placed in a mold, and liquid silicone rubber is injected into the cavity formed in the mold. Subsequently, the silicone rubber material is crosslinked and cured by heating to form an elastic layer. Then, it is cooled and demolded, and the hardness is 30 to 70 in Asker-C hardness.
Get a degree silicone rubber roller.

The silicone rubber forming the elastic layer is
Other additives and the like are mixed to obtain the required components, which are kneaded with a Banbury mixer, rolls, kneaders, etc., and a solvent is added to this mixture to mix and stir to prepare a liquid form.

After forming the above-mentioned elastic layer, the surface of the elastic layer is coated with a coating liquid as a surface layer forming material, or
Alternatively, the surface layer is formed by immersing in the coating liquid, pulling it up, and then performing drying and heat treatment.
Examples of the method of applying the coating liquid include a dipping method, a spray coating method, a roll coating method and the like. In this way, a developing roller having a two-layer structure can be manufactured.

FIG. 3 is a sectional view showing a schematic structure of an image forming apparatus using the developing device of the present invention.

The photosensitive drum 21 as a latent image carrier rotates in the direction of arrow A and is uniformly charged by the charging member 22 for charging the photosensitive drum 21.
An electrostatic latent image is formed on the surface of the laser beam 23, which is an exposing means for writing the electrostatic latent image on the surface of the laser. The electrostatic latent image is developed by applying toner, which is a developer, by a developing device 24, which is disposed in the vicinity of the photosensitive drum 21 and is held in a process cartridge detachable from the main body of the image forming apparatus. It is visualized as an image.

The development is so-called reversal development for forming a toner image on the exposed portion. Visualized photosensitive drum 21
The upper toner image is transferred onto the paper 33 which is a recording medium by the transfer roller 29 which is a transfer member. The paper 33 onto which the toner image has been transferred is fixed by the fixing device 32, discharged outside the device, and the printing operation ends.

On the other hand, the untransferred toner remaining on the photosensitive drum 21 without being transferred is scraped off by a cleaning blade 30 which is a cleaning member for cleaning the surface of the photosensitive member, and stored in a waste toner container 31 for cleaning. The exposed photosensitive drum 21 repeats the above operation.

The developing device 24 includes a developing container 34 containing a non-magnetic toner 28 as a one-component developer, and a developing container 34.
Located at the opening extending in the longitudinal direction inside the photosensitive drum 21.
Developing roller 25 as a developer bearing member installed opposite to
And the electrostatic latent image on the photosensitive drum 21 is developed and visualized. The electrophotographic process cartridge has a developing device and at least one of a latent image carrier, a charging member, a cleaning member and a transfer member,
These are integrally held and are detachably provided in the image forming apparatus.

The developing roller 25 is in contact with the photosensitive drum 21 with a contact width. In the developing device 24,
The elastic roller 26 is rotatably supported in the developing container 34 by being brought into contact with an upstream side of the developing roller 25 in a rotation direction with respect to an abutting portion of the elastic blade 27, which is a developer regulating member, with the surface of the developing roller 25. Has been done.

As the structure of the elastic roller 26, the developing roller 25 has a foam skeletal sponge structure or a fur brush structure in which fibers such as rayon and nylon are planted on a core metal.
It is preferable from the viewpoint of supplying the toner 28 to the toner and stripping the undeveloped toner. For example, it is possible to use an elastic roller 26 having a diameter of 16 mm in which polyurethane foam is provided on a core metal.

The contact width of the elastic roller 26 with respect to the developing roller 25 is preferably 1 to 8 mm, and it is preferable that the contact portion of the elastic roller 26 has a relative speed. Is set to 3 mm, and the peripheral speed of the elastic roller 26 is set to 50 mm during the developing operation.
/ S (Relative speed with the developing roller 25 is 130 mm / s)
Thus, the driving means (not shown) can be used to rotate at a predetermined timing.

[0114]

The present invention will be described in more detail with reference to the following examples, which are not intended to limit the present invention.

[Example 1] As the mandrel, a cylinder made of SUS, nickel-plated, coated with a silane coupling primer, and baked was used.

Then, the mandrel is placed on the die and the die is moved to 1
After heating at 00 ° C. for 5 minutes, conductive dimethyl silicone rubber (Asker C hardness 20 degree product) was injected into the cavity formed in the mold. Subsequently, the silicone rubber was vulcanized and cured by heating at 100 ° C. for 15 minutes, cooled, and then released from the mold to provide an elastic layer on the outer periphery of the mandrel.
After heating this at 200 ° C. for 4 hours, it is heated to room temperature and normal humidity (23
Asker in accordance with Japan Rubber Association standard SRIS0101 after being left for 5 hours or more in an environment of ℃, 55% RH)
-Using a C type spring type rubber hardness tester, A of the elastic layer only
When the sker-C hardness was measured, it was 26 degrees.

The conditions relating to the elastic layer are shown in Table 1. In Example 1, the elastic layer B was prepared.

Polybutylene adipate glycol (BA) having a weight average molecular weight of 1,000, TDI and MDI were mixed in an appropriate amount to prepare a polyol (weight average molecular weight 45,000, hydroxyl value 18 KOHmg / g).

Next, a chain-extended polyol as a main component and a required amount of TMP-modified TDI as a cross-linking material were added,
A solid solution of the urethane resin (the total amount of the chain-extended polyol and the isocyanate used as the cross-linking agent) was adjusted to 18% by mass in a mixed solution containing methyl ethyl ketone as a main solvent, and carbon black (trade name:
MA-100, manufactured by Mitsubishi Chemical) was added to the resin component in an amount of 30 parts by mass and sufficiently stirred to obtain a dip solution. The mandrel 11 provided with the elastic layer 12 is dipped in this liquid for coating, then pulled up and dried, and heat-treated at 150 ° C. for 1 hour to form the surface layer 13 on the outer periphery of the elastic layer 12. A developing roller was obtained. In Example 1, the content of the polyether-based polyol which was chain-extended mainly using diisocyanate in the surface layer was 0% by mass.

Table 2 shows the conditions for the surface layer. In Example 1, the surface layer 1 was prepared. In Table 2, "NCO
“/ OH” has a polyol (chain-extended raw polyol) as a denominator and is an isocyanate (TM in Example 1).
It is the equivalent ratio of both NCO groups and OH groups with P-modified TDI) as the molecule. The "content" is the content (mass%) of the polyether polyol contained in the surface layer and chain-extended mainly using diisocyanate.

The developing roller thus prepared was first left in an environment of normal temperature and normal humidity (23 ° C., 55% RH) for 5 hours or longer, and then, Asker-C type spring type rubber hardness meter and micro rubber hardness meter MD- Asker, a roller provided with a surface layer using Type 1 Type A (manufactured by Kobunshi Keiki Co., Ltd.)
The -C hardness and the micro hardness were measured.

As a result, the Aske of the roller having only the elastic layer is
r-C hardness (B) is 26 degrees, A of the roller provided with the surface layer
The sker-C hardness (A) is 32 degrees, and the micro hardness is 23.5.
It was degree. Furthermore, the thickness of the surface layer was determined using a microscope.

In Table 3, from the left, Example No .; used elastic layer (corresponding to Table 1), surface layer used (corresponding to Table 2); urethane resin solid of coating liquid when the surface layer was provided Concentration (% by mass); Number of coatings; A for roller with elastic layer only
scer-C hardness (degree); As of roller provided with surface layer
cer-C hardness (degree); minute hardness (degree) of the roller provided with the surface layer; thickness of the surface layer (μm).

Next, the conductive roller was allowed to stand on the flat plate and fixed so that the conductive roller did not move, and a load of 9.8 N was applied to the end of the mandrel at 40 ° C. and 95% R. ． 5 for H
After being left for a day, as a developing roller of the image forming apparatus shown in FIG.
Image evaluation was performed under the environment of%. The results are summarized in Table 4.

Further, it was used as a developing roller of the image forming apparatus shown in FIG. 3 to evaluate whether fog occurs.
The evaluation was performed in an environment where fogging is likely to occur (temperature 32 ° C., relative humidity 80%), and the evaluation was performed mainly on fogging. The results are summarized in Table 4.

In Table 4, from the left, Example No .; Ascer-C hardness (degree) of the roller provided with the surface layer; Difference in hardness (Ascer-C hardness (degree) of the roller provided with the surface layer)
-Absolute value of Ascer-C hardness (degree) of roller having only elastic layer; thickness of surface layer (μm) to absolute value of difference in hardness
The value obtained by multiplying by; microhardness (degree) of the roller provided with the surface layer;
Judgment result of whether or not the press-contacted portion appears as a streak in the image; content rate of polyether-based polyol chain-extended mainly with diisocyanate in the surface layer; judgment result of initial fog and after continuous use for 10 hours; Comprehensive evaluation of fogging; comprehensive evaluation of image quality is shown.

[Examples 2 to 19 and Comparative Examples 1 to 8] Rollers having elastic layers only were prepared using the materials shown in Table 1, and surface layers were provided using the materials shown in Table 2 to prepare developing rollers. Except what was done, it carried out like Example 1. Table 3 shows the concentration (mass%) of the urethane resin solid content of the solution used at the time of applying the materials and the materials used in Examples 2 to 19 and Comparative Examples 1 to 8 and the number of times of application. It was However, in the surface layer h used in Example 17, diamine was used instead of diisocyanate in order to extend the chain of the raw material polyol. Therefore, the content of the polyether-based polyol chain-extended using diisocyanate was 0% as shown in the table, but the content of the polyether-based polyol chain-extended using diamine was 45%.

In the present invention, isocyanates may be used as the chain extender and the cross-linking agent, respectively. The former is used when the raw material polyol is chain-extended to obtain the polyol, and the latter is the resin solution at the time of coating. It is added as a crosslinking agent that reacts with the chain-extended polyol.

The respective results are shown in Table 4.
Further, Table 4 shows the judgment as to whether or not the pressure-contacted portion on the developing roller appears as a streak in the image. Regarding the image, ⊚ is far superior to the conventional one, ◯ is superior to the conventional one, and Δ is the conventional one. Equivalent to that of the one, and x indicates that it is inferior to the conventional one with streaks. Table 3 also shows the hardness of the elastic layer and the surface layer. Regarding the evaluation of fog, ◎ is much better than the conventional one, ○ is better than the conventional one, Δ is the same as the conventional one, and × is the fog is also seen and appears on the image. Initially, images were evaluated after 10 hours of continuous use. In addition, as a comprehensive evaluation, ⊚ has significantly improved performance as compared with the conventional developing roller, ◯ has improved performance as compared with the conventional developing roller, and Δ is equivalent to the conventional developing roller. The symbol "x" represents an inferior one compared with the conventional developing roller.

[0130]

[Table 1]

[0131]

[Table 2]

[0132]

[Table 3]

[0133]

[Table 4]

[0134]

As described above, A of the roller provided with the surface layer is
Sker-C hardness is A, Aske of roller with elastic layer only
When r-C hardness is B and the thickness (μm) of the surface layer is C, 30 ≦ A ≦ 70 and | AB− ≦ 15,
| A−B | × C ≦ 450, and a roller provided with a surface layer has a microhardness of 20 to 60. By using a developing roller, the developing roller has low hardness and low compression set, and is not used for a long time. It is possible to obtain a good image even after the period.

Further, in the developing roller in which two or more layers are formed on the outer peripheral surface of the mandrel, the outermost coated surface layer is a polyether polyol in which the raw material polyol such as PTMEG is chain-extended mainly with diisocyanate. With a developing roller that is a material containing 25% by mass or more, a stable image with less fog can be obtained, and this stable image can be maintained.

Further, by using the roller structure of the first embodiment and the surface layer material of the second embodiment in combination, a developing roller is provided in which the pressure contact portion does not appear as a streak in the image and the fog is small.

The developing roller of the present invention can be suitably used as a developing roller used in electrophotography, electrostatic recording and the like. According to the present invention, an excellent developing device and an electrophotographic process cartridge capable of obtaining good image quality for a long period of time have been provided.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a developing roller shown as an example of the present invention, and is a perspective view thereof.

FIG. 2 is a cross-sectional view of the developing roller shown in FIG.

FIG. 3 is an explanatory diagram of an image forming apparatus using the developing device of the present invention.

[Explanation of symbols]

1 ... Developing roller 11 ... Mandrel 12 ... Elastic layer 13 ... Surface layer 21 ... Photosensitive drum 22 ... Charging member 23 ... Laser light 24 ... Developing device 25 ... Developing roller 26 ... Elastic roller 27 ... Elastic blade 28 ... Toner 29 ... Transfer roller 30 ... Cleaning blade 31 ... Waste toner container 32 ... Fixing device 33 ... Paper 34 ... Developing container

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Arihiro Yamamoto             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Hidenori Sato             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H077 AB03 AB04 AB14 AC04 AD06                       AD13 AD23 EA14 EA15 FA01                       FA13 FA16 FA22 FA26 FA27                       GA03                 3J103 AA02 AA14 AA23 BA41 FA18                       GA02 GA57 GA58 GA60 HA03                       HA04 HA12 HA48 HA53

Claims (18)

[Claims] 1. A developing roller comprising a mandrel, an elastic layer provided on the outer peripheral surface of the mandrel, and a surface layer provided on the outer peripheral surface of the elastic layer. Of A
Sker-C hardness is A (degree), A of roller having elastic layer only
When the sker-C hardness is B (degrees) and the thickness (μm) of the surface layer is C, 30 ≦ A ≦ 70, and | A−B | ≦
15 and | A−B | × C ≦ 450, and the roller provided with the surface layer has a microhardness of 20 to 6
A developing roller, which is 0 (degrees). 2. The developing roller according to claim 1, wherein each of the elastic layer and the surface layer is one layer. 3. The developing roller according to claim 1, wherein the surface layer contains an electronic conductive type conductive agent. 4. The developing roller according to claim 1, wherein the elastic layer contains silicone rubber. 5. The developing roller according to claim 4, wherein the elastic layer further contains 5 to 15 parts by mass of an electronic conductive type conductive agent with respect to the silicone rubber. 6. The developing roller according to claim 4, wherein the silicone rubber is a silicone rubber in which silicone is crosslinked with a curing agent having a siloxane skeleton. 7. The developing roller according to claim 1, wherein the surface layer contains a urethane resin. 8. The outermost surface layer, which is the outermost layer of the surface layer, contains 25% by mass or more of a polyether-based polyol obtained by chain-extending a raw material polyol mainly using diisocyanate. Developing roller. 9. In a developing roller having a mandrel and two or more layers provided on an outer peripheral surface of the mandrel, an outermost surface layer which is an outermost layer mainly uses a raw material polyol and diisocyanate. A developing roller comprising 25% by mass or more of a polyether-based polyol which is chain extended. 10. The method according to claim 8 or 9, wherein the starting polyol is one or more selected from polypropylene glycol and polytetramethylene ether glycol.
The developing roller according to 1. 11. The developing roller according to claim 10, wherein the raw material polyol is polytetramethylene ether glycol. 12. The developing roller according to claim 8, wherein the weight average molecular weight of the raw material polyol is in the range of 500 to 5,000. 13. The developing roller according to claim 8, wherein the chain-extended polyether polyol has a weight average molecular weight in the range of 5,000 to 80,000. 14. The developing roller according to claim 8, wherein the chain-extended polyether polyol has a hydroxyl value in the range of 15 to 160 KOHmg / g. 15. The developing roller according to claim 8, wherein the film thickness of the surface layer is 5 to 100 μm. 16. A latent image is formed as a developer image by applying a developer to a latent image carrier that carries a latent image, the container having a container for containing the developer and a developing roller for carrying the developer. A developing device for visualizing as a developing device, wherein the developing roller is the developing roller according to any one of claims 1 to 15. 17. The developing device according to claim 16, wherein the developing roller is used in contact with the latent image carrier. 18. A latent image is formed as a developer image by applying a developer to a latent image carrier that carries a latent image, the container having a container for containing the developer and a developing roller for carrying the developer. A developing device for visualizing the latent image is a latent image carrier that carries a latent image, a charging member that charges the latent image carrier, a cleaning member that cleans the latent image carrier, and a development on the latent image carrier. An electrophotographic process cartridge, which is integrally held with at least one of transfer members for transferring an agent image onto a recording medium, wherein the developing roller is the developing roller according to any one of claims 1 to 15. An electrophotographic process cartridge characterized by.