JPS60136775A - Developer carrying body and its manufacture - Google Patents

Abstract

PURPOSE:To obtain stable performance for a long term by laminating on a conductive substrate an elastic magnet layer made of a mixture of an elastomer and a magnetic material, and an electrode layer contg. a large number of conductive particles as very small electrodes in a state of each particle electrically insulated from each other. CONSTITUTION:A developer carrying body is formed by laminating on a conductive substrate 4 an elastic magnet layer 5 of a composite magnetized material consisting of a magnetic material and an elastomer, such as a halogenated polymer having no double bond on the main chain, and an electrode layer 6 containing a large number of conductive particles 6a, such as copper particles, as extremely small electrodes, dispersed into a dielectric medium, such as a room-temp. hardenable adhesive, such as acrylic urethane, in a state of each particle electrically insulated from each other and one part of it exposed out of the layer 6 surface. The surface of the electrode layer 6 is polished smoothly, and each particle 6a is held with the surface of the magnet layer 5 in contact with the bottom face of each particle 6a, and so the thickness of the electrode is equal to that of the electrode layer 6. As a result, the step for adjusting magnetic power is saved, and assembling operation is made easy. The obtained developer carrying body has high quality and a desirable edge effect on a rigid latent image bearing body.

Description

Detailed Description of the Invention Technical Field The present invention relates to a magnetic developer carrier and a method for manufacturing the same, and more particularly, a developer carrier suitable for a developing device using -component high resistance magnetic toner and a method for manufacturing the same. It is related to.

BACKGROUND OF THE INVENTION In electrostatic recording devices such as electrophotographic copying machines, facsimile machines, printers, etc., the development characteristics required of the developing device are different depending on whether the document is a line image or a solid image. FIG. 1 is a graph showing the preferable development characteristics, in which the horizontal axis represents the original image density and the vertical axis represents the copy image [1 degree].

In the figure, the solid line A indicates the development characteristics required for the edge image, and the broken line B
represents all the Jiil image characteristics required for line images. According to this, in the case of a line image (dashed line B), the solid image (
The rising slope is steeper than in the case of solid line A). The reason for this is that if the original is a helix image density, the clarity of the image will be poor if the original image density is low, so it is necessary to compensate for this by increasing the copy image density. This is because if a copy image density corresponding to the image density is obtained, the image will be sufficiently clear.

By the way, in order to increase the density of the copy image t1i of this line image, a so-called edge effect has been used conventionally.

That is, the strength of the electric field at the edge of the electrostatic latent image is stronger than the strength of the electric field at the center of the image, and as a result, a larger amount of toner adheres to the edge of the image 1, causing an edge effect. Therefore, in the case of a line image with a small image area, most of the latent image forming area corresponds to the edge and is affected by the edge effect, resulting in the copy image*m
degree becomes high.

However, this edge effect is caused by using, for example, 1-
A sufficient effect can be obtained when using a two-component system containing a step and a carrier, but an effective edge effect is obtained when using a one-component system that does not contain a carrier. The problem was that I couldn't get it.

Therefore, the applicant proposed a Kawaden device equipped with a developer carrier having a unique configuration that makes it possible to obtain the above-mentioned suitable development characteristics even when using a -component type developer (
(Japanese Patent Application No. 185726/1982). As shown in Figure 2, the developer carrier according to this proposal has a large number of hemispherical minute electrode particles 2a made of a conductive material on the outer peripheral surface of a cylindrical conductive support 1 in the circumferential direction and The electrode layer 2 is formed so as to be uniformly scattered in the width direction, and the individual electrode particles 2a are insulated from each other and held in an electrically floating state. When a magnetic developer is used, a magnet roll 3 that supplies magnetic force to support the magnetic developer inside the support 1 has its shaft 3a.
is rotatably supported and arranged. In the developer carrier configured in this way, not only is the magnet roll 3 enlarged in order to obtain the necessary magnetic force on the surface of the electrode layer 2, but also the gap G between this and the inner peripheral surface of the support must be properly managed. This is difficult, and as a result, assembly workability deteriorates, leading to a significant increase in costs. Another drawback is that it is difficult to properly control the electrode thickness t2A of each electrode particle 2a in order to obtain the desired edge effect.

Purpose The present invention has been made in view of the above points, and promotes weight reduction, improves manufacturing workability, contributes to cost reduction, and maintains desired functions for a long period of time. It is an object of the present invention to provide a developer carrier that can stably perform and a method for manufacturing the same.

Configuration Below, the configuration of the present invention will be described in detail with reference to specific embodiments. First, the structure of a developer carrier as an example of the present invention will be explained based on the schematic cross-sectional view of FIG. In FIG. 3, a cylindrical core metal 4 as a conductive support made of a conductive material such as aluminum or stainless steel is fixed to a rotating shaft 4a. An elastic magnet M5 is formed on the outer circumferential surface of the core bar 4 by forming a material made of a mixture of an elastomer such as chlorinated polyethylene and a magnetic material such as ferrite, and then applying @magnetization to the material by a known method. ing. In this case, the N and S poles may be magnetized alternately along the circumferential direction of the elastic magnet 5, and the magnetization conditions such as the distribution density of the magnetic poles may be determined by the rotation speed of the developer carrier and the above. It is desirable to set this by taking into consideration the balance between the layer thickness of the layer stacked on the layer and the moving speed of the latent image carrier that conveys the latent image to be developed. In this way, by using an elastomer (a polymer material with remarkable elasticity near room temperature) as the elastic material of the elastic magnet layer 5, excellent elasticity can be obtained, and moldability is improved, @reducing manufacturing man-hours. Contribute greatly. especially,
The chlorinated polyethylene used in this example is a halogen-based polymer that does not have double bonds in its main chain, and has weather resistance, ozone resistance, chemical resistance, and oil resistance.

It has excellent properties such as heat resistance and flame retardancy.
It is suitable as a component material for use in electrophotographic copying machines. Note that the conductive support is not limited to the cylindrical core metal 4, and may be formed in the shape of an endless belt.

On the elastic magnet layer 5 is an electrode layer 6 in which a large number of hemispherical conductive particles 6a serving as minute N poles are held in a mutually electrically insulated state (floating state) in a dielectric coupling agent 6b. is formed. The electrode layer 6 of this example is formed of a large number of copper particles in acrylic urethane as a room temperature curing adhesive, with some of the copper particles exposed on the surface as microelectrodes, and held in an insulated state from each other. In this case, the surface of the electrode layer 6 is finished smoothly without any unevenness, and each conductive particle 6a is held aligned with its bottom surface in contact with the surface of the elastic magnet 15, so that the electrode thickness t
6A and 'R pole layer thickness t6 are equal.

Therefore, the electrode layer thickness t6 is, for example, 52 to 62j when the particle size of the particles 6a used is 74 to 104μ.
m is required to be within the permissible range. The reason is as follows.

FIG. 4 is a graph showing the relationship between the electrode thickness t6A of the particle 6a and the ratio of the area exposed on the surface to the total surface area (expressed as area ratio AR). In figure M4,
Curve α2 curve β and curve γ each have a particle size of 104 mel.
The largest particle, average particle size, and particle size are 74. p
- shows each relationship for the smallest particle. According to this, in order to ensure an area ratio AR of 45% or more, which is necessary to exhibit the desired edge effect and obtain suitable development characteristics as shown in the M1 diagram, the minimum particle size (curve γ) is required. The maximum value of the electrode thickness t6A should be set to 62p- so that the ratio AR is 45% or more.Also, in order to maintain the anchor effect to prevent the particles from dropping, the maximum particle ( curve α)
It is necessary to ensure the LNi thickness t6A of 52 μm or more, which is half of the above. Therefore, the allowable range of electrode thickness t6A is 52
62p-. By the way, in the developer carrier of the present invention, as mentioned above, the electrode thickness [6A and 4iIi
Since the layer thickness t6 is equal, the process may be controlled so that the electrode layer thickness t6 falls within the above-mentioned allowable range.

In the developer 1B holder configured as described above, by integrally forming the magnetic field generating means in 71!2 parts on the same support, the above-mentioned gap management effort is eliminated and ease of assembly is improved. . Further, by using an elastomer as the medium material of the magnet, its conversion to SUa is greatly promoted.

Incidentally, when the electrical modulus of the elastic magnet layer 5 is high, the fifth
As shown in the figure, M electric conductor material is separately made of M electric material), ij,
7 may be formed between the elastic magnet layer 5 and the electrode layer 6. In this case, the layer thickness t7 needs to be set in consideration of the decrease in magnetic force on the surface of the electrode layer 6.

Next, one implementation of a manufacturing method capable of manufacturing the edge defining agent carrier constructed as described above while appropriately controlling the electrode layer thickness will be described. First, # equipped with a rotating shaft 4a as shown in FIG.
A core bar 4 of a magnet roll made of I dielectric material is formed.

After the core metal 4 is formed, its outer circumferential surface is cleaned and then an elastic magnet layer is deposited thereon. A preferred embodiment of this process is
This is shown in FIGS. 7(a) to 7(C). According to this method, as shown in FIG. 7(a), first, a magnetic material such as ferrite is added to an elastomer such as chlorinated polyethylene which has been kneaded, and various compounding agents such as a vulcanizing agent are added depending on the purpose. , and crosstalk with 2nd day - 8th grade. Then, the composite elastic material 5', which has been kneaded and has a uniform composition, is formed into a sheet shape and wound around the curved surface of the core bar 4 as shown in FIG. 7(b). Next, a workpiece (hereinafter referred to as work W) in which a composite elastic material sheet 5' is wrapped around a core metal 4 is placed in a cavity 9a of a mold 9 of a pressure press, and heated and vulcanized while applying pressure. . As a result, Part 8 (b)
As shown in the figure, a composite elastic base 5' having a substantially uniform layer thickness t5 is formed on the circumferential surface of the core metal 4. After that, if magnetization is performed in the usual manner, an elastic magnet layer 5' in which, for example, N and S poles are provided alternately along the circumferential direction, as shown in FIG. 8(a).
is formed.

On the surfaces of the elastic magnets 1 to 5- layered,
Usually, a large number of irregularities are formed, and if left as is, it will be inconvenient in terms of electrode thickness management. Therefore, first surface processing is performed using a cylindrical grinder or the like to make the surface smooth and to make the layer J.
ji7. Adjust ts- to a desired value, for example, 5 to 3 mm. In this example, as shown in FIG. 9, the first external shape processing is performed by cylindrical grinding with the center of the workpiece W set at Ht4=. In this case, by gripping the rotating shaft 4a of the core metal 4 with the support 1O of the cylindrical grinder and performing the grinding process, the elastic magnets 1 to 1 with a uniform layer thickness t5 can be produced without eccentricity.
Layer 5 is formed.

After forming the elastic magnet layer 5, the surface of the elastic magnet layer 5 is cleaned, and then, as shown in FIG.
A dielectric first adhesive 6b such as room temperature curing type acrylic urethane is applied to the surface of the substrate by spraying. As a result, the first adhesive MM 6 b as shown in FIG. 11 is deposited, and its film thickness t6B is such that the particle size to be sprayed in the next step (see FIG. 12) is, for example, 74 to 74. A suitable thickness is about 3 to 15 μm so that the conductive particles 6a of 1104u can be easily held in contact with the surface of the elastic magnet layer 5. In this case, the rotating shaft 4a of the core metal 4 is horizontally and rotatably supported, and the work W is rotated at an appropriate speed while the air spray 11 is reciprocated at a predetermined speed to spray the adhesive as described above. By repeating this process, it is possible to easily deposit the first adhesive film 6b with a uniform thickness.

After the first adhesive film 6b is applied, a large number of conductive particles are deposited approximately evenly on the surface of the elastic magnet layer 5 before it is cured. As shown in FIG. 12, for example, as shown in FIG. 12, copper particles having a particle size of 74 to 104 μm are stored as conductive particles 6a many times in a tray 12 equipped with a dispersion port 12a, and then placed horizontally. The 1-ray 12 is moved back and forth at an appropriate speed while being tilted appropriately while being supported by the rotating workpiece W, and the particles 26a are dropped one by one from the spraying port 12a and uniformly sprinkled onto the first adhesive film 6b. It's fine as long as it's H. In this case, if each conductive particle 6a used here is coated with a dielectric material such as styrene butyl acrylate-1 or methyl methacrylate (MMA) in advance, it will be free from gravity due to its natural falling properties. Even if the particles 6a are scattered randomly, the individual particles 6a can be more reliably held in the first adhesive layer 6b in an electrically fringed state (floating state) with respect to the surroundings.

By the way, each particle 6a sprinkled on the first adhesive film 6b naturally sinks to the surface of the elastic magnet layer 5 because the thickness of the first adhesive film 6b is as thin as 3 to 15 cm. Therefore, as shown in FIG. 13, the bottom surface of each particle 6a can be easily and reliably aligned with the surface of the repellent magnet layer 5 simply by allowing the individual particles 6a to fall naturally. In this example, copper particles are used as the conductive particles 6a, but the present invention is not limited to this, and particles of other conductive materials such as brass, phosphor bronze, or stainless steel can also be used. However, in this case as well, it is necessary to appropriately set the thickness of the first adhesive film 6b according to the size and specific gravity of the particles so that the particles do not float and settle onto the surface of the dielectric layer 2. . Also, instead of supporting the workpiece W horizontally as described above, the workpiece W is supported and rotated in a moderately inclined state as shown in FIG.
Similarly, a may be uniformly dispersed by gravity. This makes it possible to further improve the adhesion density of the particles 6a.

Next, the first adhesive 6b is dried almost completely.

In this case, in order to efficiently dry the workpiece W, it is necessary to support it horizontally and rotate it while heating it by irradiating it from the outside with a far-infrared heater, by blowing hot air, or by placing it in an electric furnace. Good. Note that heating is not necessarily required in this step; for example, if a quick-drying adhesive is used, it may be sufficient to blow air or leave it for an appropriate period of time.

After the first adhesive I'll 6b has almost completely dried and hardened, the dielectric second adhesive 6b is applied again as shown in FIG.
- is thickly coated (overcoated) on the conductive particles 6a and the first adhesive film 6b in the same manner as the previous time. in this case,
If the same adhesive material as the previous one is used, the two will surely adhere to each other and the particles 6a can be more firmly fixed in contact with the surface of the rubber magnet layer 5, which is advantageous in terms of durability. However, as long as the particles 6a can be reliably fixed by adhering to each other, a combination of dielectric adhesives made of different materials is also possible. By applying the adhesive in two parts with a drying process in between in this way, the first adhesive film 6b deposited earlier is not redissolved, and therefore each particle 6a is reliably treated without being suspended. The particles can be firmly fixed in a depressed state on the surface of the elastic magnet layer 5, and as described above, the electrode thickness of each particle can be controlled by replacing the tube II with an easy electrode layer thickness.

Once the adhesive has been applied thickly, let it dry and harden.

In this case, as in the previous first adhesive drying process, the work W may be dried while being rotated and supported horizontally. As a result, as shown in FIG. 16, the first adhesive film 6b, the electrically conductive particles 6a, and the second adhesive layer 5 are laminated on the elastic magnet layer 5 without the thickly applied second adhesive layer 6b dripping. The layer thickness t6- of the electrode layer 6' (before part of the particles 6a is exposed on the surface) including the agent 61)' becomes uniform. In this way, an electric I4i layer 6' having a layer thickness of about 150 μm, for example, is formed.

After forming the electrode layer 6', as shown in FIG. 17, a second surface treatment is applied to the surface of the N-pole layer 6' to smooth the surface and expose a portion of each conductive particle 6a on the surface. In this way, the electrode layer 6' is finished into the electrode layer 6. Here, it is required that the layer thickness t6 of the electrode layer 6 is within the allowable range of 52 to 62 μm, but in this example, the machining axis is always constant by using the rotation axis 4a of the core metal 4 as the machining axis. Therefore, the layer thickness t6
can be easily kept within the above tolerance range. That is,
When carrying out this second surface processing with a lathe, cylindrical grinder, etc.,
As shown in the figure, the rotary shaft 4a, which was used as the processing axis during the first surface processing of the elastic magnet layer 5' (see FIG. 9), is similarly gripped by a support 1O- such as a chuck in this step, so that both steps can be carried out. The machining axes in the two lines coincide with each other, so that the layer thickness t6 is made uniform with high accuracy. In this example, in the drying process after thick coating of the second adhesive 6b-, the hanging of the second adhesive 6b' before hardening is prevented by the method described above, so that the electrode layer thickness ts- before finishing is approximately uniform. Since the process is controlled so that -, the desired electrode layer 6 can be obtained even by a superfinishing method based on the outer peripheral surface or a centerless grinding method, which does not require aligning the machining axes. In addition, when the workpiece W is not cylindrical but has an endless belt shape, the workpiece W is stretched between an appropriate number of rollers and rotated, and the surface is polished by pressing a rotating grindstone against it in the same way as in cylindrical grinding. All you have to do is grind it.

As described above, the second surface treatment is actually carried out over the entire circumferential surface of the electrode layer 6', and as shown in FIG. form. After this, if stains such as cutting oil are washed away, the developer carrier 12 as a final product is completed.

In the above embodiments, the process was carried out after forming the composite elastic layer 5- without discussing magnetization of the composite elastic layer, but this magnetization process was carried out in other cases, for example, when the composite elastic layer 5- was subjected to the first surface treatment. It may be carried out after the second adhesive 6b has been dried, or after the electrode layer 6' has been subjected to the second surface treatment. However, considering the adhesion of dust after magnetization and the occurrence of scratches on the outer peripheral surface due to handling during magnetization, it is desirable to magnetize the second adhesive 6b after drying. Further, although the adhesive application step is divided into two steps, it may be divided into one step or three or more steps as necessary.

Next, one embodiment of a method for manufacturing a developer carrier having a dielectric layer 7 interposed therebetween shown in FIG. 5 will be described. In this case, in the above-described embodiment, the formation process of the N-induced layer 7 may be performed by applying the first
It is simply inserted after the surface finishing step, and except for this point, the structure is the same as that of the above-described embodiment.

To form the N-induced layer 7, first, as shown in FIG.
This is then heated. Then, a thermosetting dielectric powder 7' such as epoxy resin is applied to the workpiece W using a coating gun 14 using an electrostatic coating method. In this case, the heating temperature of the workpiece W may be set to around 180° C. of the melting humidity of the M electric powder 7', that is, the melting temperature of the epoxy resin in this example. Furthermore, by repeatedly painting while moving the coating gun 14 back and forth parallel to the workpiece W at a constant speed, a uniform coating film 7- can be easily obtained as shown in FIG. After the coating is completed, the workpiece W is continued to be rotated for a suitable period of time while being heated to harden the dielectric coating film 7'.

By curing in this manner, the film thickness t7- of the dielectric coating 11a7- becomes entangled not only in the longitudinal direction but also in the circumferential direction. After forming the dielectric coating film 7-, the rotating shaft 4
If surface processing is performed using a lathe, cylindrical grinder, etc. while supporting the workpiece W while supporting the workpiece W, as shown in FIG.
A dielectric layer 7 having a uniform layer thickness [7] is formed. After this, if the electrode layer 6 is formed while appropriately controlling the thickness of the N-pole layer as in the above-mentioned embodiment, the developer carrier 1 as an @1 product can be formed.
5 is obtained. Incidentally, in this embodiment, it is also possible to omit the first surface treatment on the elastic magnet layer 5.

As detailed above in JL 1, according to the present invention, an elastic magnet layer using an elastomer as a medium is integrally formed on a conductive support, and an electrode layer is formed so that the electrode thickness and the electrode layer thickness are equal. By doing so, the effort of adjusting the magnetic force can be saved, and the electrode thickness can be easily and reliably managed by substituting the electrode layer thickness. Therefore, it is possible to efficiently and easily manufacture a high-quality developer carrier that has a sufficient magnetic force, promotes weight reduction, and exhibits a desired edge effect at a low cost. In addition, by using an elastomer as an elastic material, the moldability of the elastic magnet layer is improved, further promoting cost reduction, and ozone resistance, chemical resistance, heat resistance, etc. are improved, and the durability of the developer carrier is improved. sex increases significantly. It should be noted that the present invention is not limited to the specific embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the present invention. For example, when applying an adhesive, it is also possible to use other immersion molding methods (dip molding method) or the like. In addition, when forming the dielectric layer 7, the material used is 1! ! Polyimide, ABS
Resin etc. can also be used, and this is the same as M1 adhesive 6b.
Alternatively, the same type of dielectric substance may be used.

[Brief explanation of the drawing]

FIG. 1 is a graph showing suitable development characteristics, FIG. 2 is a schematic cross-sectional view showing a conventional developer carrier, and FIG. 3 is a diagram showing a developer carrier 12 as an embodiment of the present invention. 4 is a graph showing the relationship between electrode thickness and its area ratio, and FIG. 5 is a schematic sectional view showing a developer carrier 15 as another embodiment of the present invention. Figure 6 is a perspective view showing the core metal 4 in one embodiment of the method of the present invention, and Figure 7 (a
) Figures to M7 ((f) Figures are the same composite elastic layer 5.
8(a), 8(a), 8(a) and 8(a).
b) The figures are a schematic side view and a schematic front sectional view respectively showing the elastic magnet layer 5', FIG. 9 is a schematic sectional view similarly showing the first surface processing step, FIGS. 10 and 11. 12 and 13 are schematic cross-sectional views showing the first adhesive adhesion step and the amount formed, respectively, and FIGS. 12 and 13 are schematic cross-sectional views showing the conductive particle adhesion step and the amount formed, respectively. Figures 14 and 14 are schematic cross-sectional views showing a modified example of the particle adhesion process, and Figures 15 and 16 are schematic cross-sectional views showing the second adhesive adhesion process and its formation amount, respectively. , 1st
Figure 7 is a schematic cross-sectional view showing the second surface processing step,
FIGS. 18 and 19 are schematic cross-sectional views showing the dielectric layer forming step and the amount of the dielectric layer formed in another embodiment of the method of the present invention. (Explanation of symbols) 2.6: Electron 1!1l1 4: Core bar 5': Composite elastic layer. Elastic magnet layer (before surface treatment) 5: Composite elastic layer. Elastic magnet layer (after surface processing) 7: Dielectric layer Patent applicant Riko Co., Ltd. Kazuyo Masato Small (n positive Open chain 1 Figure 2 Figure 2 31-4 41,1 Electrode thickness = 2 satμm1 5u Figure 6 Figure 11 Figure 6b Figure 12 61''I Figure 13 Figure 14 Figure 16 Figure 17 Figure 18 Figure 3 Figure 19

Claims (1)

[Claims] 1. An elastic magnet layer formed by magnetizing a composite of an elastomer and a magnetic material and a large number of conductive particles as microelectrodes are arranged on an M4 conductive support to mutually generate electricity. 1. A developer carrier comprising a layered electrode layer which is maintained in a physically insulated state. 2. The developer carrier according to item 1 above, wherein the elastomer is a halogen-based polymer having no double bond in its main chain. 3. The developer carrier according to item 2 above, wherein the halogen-based polymer is chlorinated polyethylene. 4. forming a support made of a conductive material; depositing a composite elastic layer made of an elastomer and a magnetic material on the support; surface-treating the composite elastic layer; A step of magnetizing the elastic layer, applying a dielectric adhesive to the surface of the composite elastic layer, and attaching a large number of W4 lightning particles as microelectrodes on the composite elastic layer to form an N-pole layer. and a step of subjecting the electrode layer to a surface treatment to expose a portion of each of the conductive particles on the surface. 5. The method for producing a developer carrier according to item 4 above, wherein the elastomer is a halogen-based polymer having no double bond in its main chain. 6. The method for producing a developer carrier according to item 5 above, wherein the halogen-based polymer is chlorinated polyethylene. 1. The method for manufacturing a developer carrier according to item 4 above, characterized in that the surface of the N-conducting particles is coated with a dielectric film in advance before being deposited in 1-i. 8. In the above whistle item 4, the step of forming the electrode layer includes the step of applying a dielectric first adhesive to the surface of the composite elastic layer, and the step of applying a dielectric first adhesive to the surface of the composite elastic layer, and depositing the conductive particles on the layer; drying the first adhesive; and overcoating the first adhesive and the conductive particles with a second dielectric adhesive. A method for manufacturing a developer carrier, characterized in that: 9. forming a support made of a conductive material; depositing a composite elastic layer made of an elastomer and a magnetic material on the support; magnetizing the composite elastic layer; A step of forming a dielectric layer made of a dielectric material on the surface of the elastic layer, a step of surface-processing the dielectric layer, and applying a 4-electrical adhesive to the surface of the dielectric layer and forming a microelectrode on the dielectric layer. A developer characterized by comprising the steps of: adhering a large number of conductive particles to form an electrode layer; and applying a surface treatment to the electrode layer to expose a portion of each conductive particle to the surface. Method for manufacturing a carrier. 10. The method for producing a developer carrier according to item 9 above, wherein the elastomer is a halogen-based polymer having no double bond in its main chain. 11. The method for producing a developer carrier according to item 10 above, wherein the halogen-based polymer is chlorinated polyethylene.