JPS6078460A - Manufacture of developer carrier - Google Patents

Abstract

PURPOSE:To obtain an image of high quality by forming a dielectric layer on an electrically conductive support, coating the layer with a dielectric adhesive layer, sticking many electrode particles to the dielectric layer to form an electrode layer, and carrying out surface working on the basis of the surface of the electrode layer to expose partially the electrode particles. CONSTITUTION:A dielectric film is formed on an electrically conductive cylindrical support 1, and the surface of the film is smoothened to form a dielectric layer 4 of a thickness t4. The layer 4 is coated uniformly and thinly with a dielectric adhesive layer 2b, and many electrode particles 2a are sprinkled and stuck to the layer 4. After drying the layer 2b, the particles 2a are coated with a dielectric adhesive 2b, and the adhesive 2b is dried and cured. Surface working is then carried out by means of a super-finishing unit 10 on the basis of the peripheral surface S so that the thickness of the resulting electrode layer is regulated to t2. More than the halves of the particles 2a are embedded in the electrode layer so as to prevent the falling of the particles, the total area of the exposed particles 2a is regulated to >=45% of the surface area of the electrode layer, and the thickness t2 is made equal to the thickness t2A of the particles 2a. Thus, an electrode layer 2 of a uniform thickness is formed, and a developer carrier giving stably an image of high quality is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION 1L1 The present invention relates to a method for producing a developer carrier, and more particularly, to a method for producing a developer carrier suitable for a developing device using -component high-resistance magnetic 1 to 1-component. It is.

BACKGROUND ART In electrostatic recording devices such as electrophotographic copying machines, facsimile machines, and printers, the development characteristics required of the development device are different depending on whether the document is a line image or a solid image. Figure 1 is a graph showing the suitable development characteristics.
The horizontal axis represents original image density, and the vertical axis represents copy image density.

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

By the way, the so-called edge effect has been conventionally used to increase the density of the copied image of this line image.

That is, the electric field strength at the image edges of the electrostatic latent image is stronger than the electric field strength at the image center area, resulting in a larger amount of toner adhering to the image edges, resulting in 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 subject to the edge effect, resulting in a high value of the density of the copied image.

However, this edge effect is sufficiently effective when using a two-component developer containing 1 to 4 toner and a carrier, but when using a one-component developer that does not contain a carrier. In this case, there was a problem that an effective edge effect could not be obtained.

Therefore, the applicant of the present application has proposed a developing device equipped with a developer carrier having a unique configuration that makes it possible to obtain the above-mentioned suitable development properties even when a -component type developer is used.
<Patent Application No. 185726/1983). As shown in FIG. 2, the developer carrier according to this proposal has a large number of hemispherical minute electrode particles 2a made of a conductive material arranged around the outer periphery 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. Note that when a magnetic developer is used, a magnetic roller (not shown) is provided inside the support 1 3.

A suitable method for manufacturing such a developer carrier is -
C. Apply the adhesive 2b on the conductive support layer 1, sprinkle the conductive particles 2a on top of it, and then process the outer diameter using a lathe or the like to smooth the surface of the electrode layer 2 and remove the electrode particles. A method has been proposed in which a hemispherical shape is shaved and a part of it is exposed on the surface. In this case, in order to obtain the desired edge effect, the ratio (area ratio) of the area exposed on the surface of the N-pole particle 2a to the total surface area of the electrode layer 2 must be set to a predetermined value or more, for example 4.
It is required to secure 5% or more. Moreover, the electrode particles 2a
It is also necessary to avoid removing more than half of the volume of each particle to prevent detachment. In order to satisfy the above conditions, for example, when the particle size of each electrode particle is about 74 to 104, the electrode layer 2 may be formed so that the electrode thickness is 52 to 62. In addition, the electrode thickness is the second
As shown in the figure, the excised particle 2A (1) electrode layer thickness t2
Pointing to the thickness t2A in the direction. The reason is as follows.

Figure 3 shows the thickness t2A of the electrode particle 2a and its area ratio AR.
It is a graph diagram showing the relationship between. In FIG. 3, the curve α9 curve β and the curve γ correspond to the maximum electrode particle with a particle size of 1104p, the electrode particle with an average particle size, and the particle size of 74p, respectively.
Each relationship in the minimum electrode particle of pm is shown. According to this, 4
In order to secure an area ratio AR of 5% or more, the electrode thickness t must be adjusted so that the area ratio AR is 45% or more with the smallest particle (curve γ).
The maximum value of 2A should be set to 62 units. Also, due to the anchor effect, the particle size of 11121! In order to prevent III, the thickness t2 is 52p- or more, which is half of the maximum particle (curve α).
It is necessary to secure A. Therefore, the allowable range of the thickness t2A of the electrode particles 2a is 52 to 62JIff+.

However, when machining the outer diameter of the electrode layer using a turning method based on @ (machining @) that supports a workpiece such as a lathe,
It is difficult to suppress the fluctuation width of the layer thickness of the electrode layer 2 to less than 10 pffI, which is the allowable range width of the electrode thickness t2A, and therefore it is difficult to keep the electrode thickness t'2A within the above-mentioned allowable range.
(See Figure 2). That is, as shown in FIG. 4, since the conductive support 1 needs to be formed with a thin wall, it is difficult to process the spigot parts 1a at both ends with high precision. A clearance P is likely to occur between the two. When the clearance P occurs, the central axis Co of the support 1 and the central axis C+ of the support T
It becomes difficult to match the machining axes. the result,
When an eccentricity of Δd occurs between the central axis CO and the processing axis C1, the fluctuation range VR of the electrode layer thickness t2 that occurs due to this is:
Maximum layer thickness t2.

If the minimum values are txAx and tM+N, respectively, VR= t
MAX-t+q+N=2・Δd. Therefore, in order to keep the electrode thickness t2A within the allowable range of width 10Jl111, each electrode particle 2a must have its bottom surface at the same level 1'' (
Processing 1! under the precondition that it is aligned with (see Figure 2). h It is required to keep the eccentric opening △d of C+ to less than half of that, 5 units. It is extremely difficult to adjust to such severe processing conditions, which increases the number of man-hours and causes loss of production.

Purpose The present invention has been made in view of the above points, and it is possible to easily create a developer carrier capable of exhibiting a desired edge effect and stably obtaining high image quality even with a one-component developing agent. The purpose is to provide a manufacturing method that can be used to manufacture products.

JL Hereinafter, the structure of the present invention will be explained in detail based on specific examples. As shown in FIGS. 16(a) and 16(b), the developer carrier manufactured by the manufacturing method of this example is produced by forming a dielectric layer 4 on a conductive support 1, and then forming an electrode. This is a developer carrier 11 configured by laminating layers 2.

Note that the dielectric layer 4 is formed on the conductive support 1 in order to prevent the edge effect.
The necessary dielectric area is provided on the top to ensure (M frost thickness).

First, as shown in FIG. 5, the conductive support 1 is formed into a cylindrical shape. In this case, if the present invention is applied to a developing device in which a magnetic developer is used and the developer is supported by magnetic force, the conductive support 1 is formed of a thin non-magnetic material such as stainless steel. Note that the support body 1 is not limited to a cylindrical shape, and may be formed in other shapes, such as an endless belt shape.

Next, after degreasing the outer peripheral surface of the support 1, a dielectric coating made of a dielectric material is uniformly applied over the entire outer peripheral surface. Specifically, as shown in FIG. 5, for example, a cylindrical sheathed heater 6 with a heater 5 mounted therein is horizontally rotatably provided, and the support 1 formed as described above is fitted onto the sheathed heater 6 for support. While heating the body 1 to around 180°C and rotating both substantially integrally at a predetermined speed, the electrostatic coating gun 7
Then, the dielectric powder 4- is uniformly sprayed onto the outer peripheral surface of the support 1 by an electrostatic coating method. In this case, dielectric powder 4
- is preferably a thermosetting resin powder such as an epoxy resin powder. Then, connect the paint gun 7 to the sheathed heater 6.
The coating may be set on a holding table (not shown) that can be moved back and forth at a constant speed in parallel to the surface of the substrate, and the spraying operation may be repeated until the desired layer thickness of, for example, about 500 pm is reached. After spraying is completed, the support 1 is continued to be rotated for an appropriate period of time while being heated by the sheathed heater 6, and the dielectric coating film 4 is cured as shown in FIG. As a result, the dielectric coating 114-
The film thickness t4- is approximately uniform not only in the width direction but also in the circumferential direction. Note that the heating method 'C of the support 1 may be a method of heating from the outside using a far-infrared heater or the like.

Deposited dielectric coating Il! Although many irregularities are usually formed on the surface of 4-, this surface is required to be smooth to some extent in order to keep the thickness of the electrode particles within the above-mentioned tolerance range. Therefore, the applied dielectric coating 4
- The surface is smoothed by processing the outer diameter using a lathe or the like, and a dielectric R4 having a layer thickness t4 of about 400 layers is formed as shown in FIG. Incidentally, it is also possible to carry out the main outer diameter machining using other tools such as a cylindrical grinder.

After forming the dielectric Ti layer 4 by outer diameter processing, the surface of the dielectric layer 4 is cleaned, and then, as shown in FIG. Evenly spray adhesive such as hardening type acrylic urethane. As a result, the adhesive film 2b as shown in FIG. 9 is deposited, and the thickness t2B of the adhesive film 2b is such that the electrode particles 2a dispersed in the next step (see FIG. 10) have a particle size of, for example, 74 mm. In the case of copper particles having a diameter of 104 μm to 104 μm, the preferred thickness is about 3 to 15 pm, which allows the dispersed particles to reliably adhere to the surface of the dielectric layer 4. In this step as well, the intermediate product in which the dielectric layer 4 is deposited on the support 1, which is the workpiece (hereinafter referred to as work W), is treated with an appropriate material as in the case of forming the dielectric film. If the adhesive film 2b is supported horizontally while being rotated at a high speed, and the above-described adhesive is repeatedly applied along this direction, the adhesive film 2b having a substantially uniform thickness can be easily formed.

Once the adhesive has been applied, and before it hardens, a large number of electrode particles are deposited substantially evenly on the surface of the dielectric layer.

For this attachment method, for example, as shown in FIG. 10, a large amount of copper particles having a particle size of 74 to 104 μm are stored as electrode particles 2a in a tray 9 equipped with a dispersion port 9a.
The tray 9 is moved back and forth at an appropriate speed along the horizontally supported and rotated workpiece W and is tilted appropriately, and the spraying port 9a is
The electrode particles 2a may be dropped little by little from the adhesive film 2b and sprinkled onto the adhesive film 2b to uniformly distribute the electrode particles 2a. This allows the first
As shown in FIG. 1, each electrode particle 2a is attached substantially uniformly to the surface of the dielectric layer 4 while being in contact with the surface. In this example, each electrode particle 2a to be attached is coated with a dielectric material such as acrylic lacquer in advance, so even if it is scattered randomly by natural fall, the individual electrode particles 2a can be reliably spread around the surrounding area. It can be attached in an insulating state (floating state) on the other hand. Also, l of adhesive H2b! Since the thickness is as thin as 3 to 15 fim, no buoyancy is generated to float the dispersed copper particles 2a having a diameter of 74 to 104 μm, and each particle 2a naturally sinks to the surface of the dielectric layer 4. Therefore, as shown in FIG. 11, the bottom surface of each electrode particle 2a can be easily and reliably aligned with the surface of the dielectric layer 4 simply by allowing the individual electrode particles 2a to fall naturally. In this example, copper particles are used as the electrode particles 2a, but the electrode particles 2a are not limited to this, and particles of other conductive materials such as brass, phosphor bronze, or stainless steel can also be used.

Next, after drying and curing the adhesive 2b almost completely,
As shown in the figure, the dielectric adhesive 2b- is again thickly coated (overcoated) on the electrode particles 2a and adhesive 2b in the same manner as the previous time. In this case, if the same adhesive as the previous one is used, the two will surely adhere to each other and the electrode particles 2a will be more firmly fixed in contact with the surface of the dielectric layer 4, which is advantageous in terms of durability. be. However, particles 2 adhere to each other
As long as a can be reliably fixed, combinations of dielectric adhesives made of different materials are also possible. In this way, by applying the adhesive in two steps with a drying process in between, re-melting of the previously applied adhesive 2b is avoided, so each electrode particle 2a is not suspended and the dielectric layer 4 It can be firmly fixed in a state where it is sunk to the surface, and the prerequisite for keeping the electrode thickness within a predetermined tolerance range of locating the bottom surfaces of each particle 2a on the same level as described above can be easily achieved. .

After applying a thick coat of adhesive, let it dry and harden. In this case, as shown in FIG. 13, if the workpiece W is inserted into the sheathed heater 6 and horizontally supported and rotated as well as heated and dried in the same way as when forming the dielectric layer, the thickly applied adhesive 2b'' Adhesive 2 laminated on dielectric layer 4 without dripping
b. The layer thickness 12- of the electrode layer 2' (a state before a part of each particle 2a is exposed to the surface), which is a combination of the electrode particles 2a and the thickly coated adhesive 2b=, becomes uniform. In this way, an electrode layer 2' having a layer thickness 12- of about 150 layers is formed, for example.

Then, as shown in FIG. 14, the electrode layer 2'
The surface of the electrode layer 2 is finished by processing the outer diameter of the electrode layer 2 to make the surface smooth and to expose a portion of each electrode particle 2a to the surface. By the way, in the method of the present invention, since each electrode particle 2a is fixed in a state in which each electrode particle 2a is in contact with the surface of the dielectric layer 4, the layer thickness t2 of the finished electrode layer 2 is equal to the electrode thickness t2A. Therefore, if the layer thickness t2 of the electrode layer 2 is kept within the allowable range of the electrode thickness t2A of 52 to 62 μm, the electrode particles 2
Ensure that the exposed area ratio AR of a is 45% or more, and the particles 2
A desired electrode layer 2 in which a is difficult to detach can be obtained. Therefore, in the method of the present invention, the main outer diameter machining step is carried out by a surface machining method using the outer circumferential surface S of the workpiece W (the surface of the electrode layer 2') as a reference. One of the methods suitable for this step is, for example, a superfinishing method, and specific examples thereof will be described below.

In this example, as shown in FIG.
A workpiece W is set on the main axis A of the lathe and rotated about the longitudinal axis, and the grindstone 10a is pressed against the outer circumferential surface of the work W while being moved in the longitudinal axis direction to grind the circumferential surface. In the super finishing unit 10, the grindstone 10a as a tool is
It is attached to the tip of the stone guide 10b. The stone guide 10b includes an air cylinder 10C, which moves the grindstone 10a up and down. Moreover, this air cylinder 10c has the effect of acting as a cushion to absorb fluctuations in the machining surface during machining work.

The stone guide 10b is connected to the superfinishing head 10d. This super finishing head 10d has the above-mentioned grindstone 1.
Vibration means for generating vibration in the longitudinal axis direction of 0a (
(not shown) is built-in, for example, the amplitude is 1 to 6+1.
1111, vibrations having a frequency of 1,900 to 3.200 CPM are generated in the grindstone 10a via the stone guide 10b and the like. The superfinishing head 10d is attached to a tool post B that reciprocates a tool such as a cutting tool of the lathe along the main axis A. Therefore, the superfinishing head 10d, the stone guide 10b, and the grindstone 10a are integrally moved together with the carriage B at a predetermined speed along the main axis A, and the grindstone 10a, which is a tool, is fed along the longitudinal axis direction of the workpiece W. Action is performed. The grindstone 10a used in this example is made by hardening particles of black silicon carbide, green silicon carbide, brown alumina oxide, white alumina oxide, etc. with a binder made of polyvinyl alcohol and a thermosetting resin.

When processing the outer diameter of the surface of the electrode layer 2' using such a manufacturing apparatus, first, both ends of the work W are supported via the support jig T to the main shaft of the lathe. Next, the air cylinder 10b is activated and the grindstone 10a is placed on the circumferential surface of the supported workpiece W, for example, by I.
K (Press with a relatively light pressure of about J / Cm'. After setting the workpiece W and the grindstone 10a, start rotation to the main shaft, vibration of the super finishing l\rad 0d, and feeding operation of the carriage B, respectively. In this way, if the outer diameter of the electrode layer 2- is machined by the super finishing method, it will be stable regardless of the position of the machining axis of the workpiece W, which is determined by the support of the main axis A. C Desired 52 to 621 Iffl(7) @thickness t as shown in FIG. 16(a) and FIG. 16(b)
2 is formed.

That is, as shown in Fig. 17(a) and Fig. 17(b), the support shaft CA on which the main shaft of the lathe supports the work W is the central axis Cw of the work W (in this example, strictly speaking, the dielectric H4 If the workpiece W is eccentric by Δd from the machining axis (during outer diameter machining), the fluctuation width of the outer circumferential surface level H in contact with the grindstone 10a of the workpiece W rotated around the support axis OA will be twice as large as 2·Δd. However, this fluctuation is absorbed by the cushioning effect of the air cylinder 10b mentioned above, and even when the outer circumferential surface level with respect to the grindstone 10a shown in FIG. 7(a) is the lowest, the first
7(+1) Even when the outer circumferential surface level 1 shown in FIG. Therefore, in FIG. 14, the thickness t2R of the workpiece W to be ground is made uniform over the entire circumferential surface with reference to the initial electrode layer 2-surface S (the surface before grinding) of the workpiece W.

In this example, since the N-pole N2- is formed so that the layer thickness t2'' is approximately equal to 150μ...C, super-finishing is performed so that the grinding thickness t2R is 88 to 98μm over the entire circumference. zu“
That's fine. According to super finishing processing, the total grain size is 5. ooo number 111 (if stone is used, the surface roughness is at least 0.05
Since a finished surface of approximately R7 can be obtained, if the variation range of the layer thickness t2- of the electrode layer 2' is suppressed to 10JIff1 or less,
Finally, a desired electrode layer 2 having a layer thickness t2 within the range of 52 to 62 μm can be easily formed. In addition, in this case, as shown in FIG. 17, the outer diameter machining @C4 at the time of forming the dielectric layer 4 was shifted from the central axis Co of the support 1, so the layer thickness of the dielectric layer 4 became uneven. However, the accuracy of this superfinishing process is not affected, and the electrode layer 2 having a uniform layer thickness t2 can be formed stably and with high precision.

Note that the processing method for this type of extreme layer finishing step based on the outer circumferential surface is not limited to the super finishing method, and a centerless cylindrical grinding method as shown in FIG. 19 can also be adopted. If you use this method,
The workpiece W is inserted between the ωI grinding wheel 12 and the adjustment grindstone 13 that feeds the workpiece, and while the support is supported by the plate 14, it is sufficient to uniformly grind the workpiece from the outer peripheral surface. Outer diameter machining based on the outer peripheral surface can also be easily performed.

By processing the outer diameter of the electrode layer surface using the outer peripheral surface as a reference as described above, the layer thickness t2, that is, the electrode thickness t2A, is 52 to 62 - as shown in FIGS. 16(a) and 16(b).
The electrode layer 2 is formed uniformly over the entire circumferential surface, and the electrode layer 2 is reliably within the permissible range of . After that, if the dirt from the abrasive material etc. on the surface is cleaned, the developer carrier 11 as a final product is obtained.
is completed.

In the above embodiment, the process of applying the adhesive is divided into two processes, but it may be divided into one process or three or more processes as necessary. In addition, the material of the dielectric layer 4 and the adhesive 2b
It is also possible to use the same or the same type of dielectric material. Furthermore, the material for the dielectric layer 4 is not limited to thermosetting resins, but also thermoplastic resins such as polyimide and ABS can be used.

Effects As detailed above, according to the present invention, the surface processing for finishing the electrode layer, which determines the electrode thickness, is carried out based on the outer surface, so that the machining axis can be adjusted when forming the electrode layer, which requires precision. No settings required.

Therefore, a developer carrier having a desired electrode thickness and capable of stably exhibiting suitable development characteristics as shown in FIG. 1 can be manufactured with a shorter number of man-hours and at a lower cost. It should be noted that the present invention is not limited to the above-described specific embodiments, and it goes without saying that numerous modifications can be made within the technical scope of the present invention. For example, when applying adhesive, it is also possible to use other immersion molding methods (dip molding method), etc.
The step of attaching the electrode particles can also be carried out by rolling the workpiece coated with the adhesive over a particle bed covered with electrode particles. Furthermore, the surface processing for forming the dielectric layer 4 may also be performed based on the outer surface, for example, by a superfinishing method.

[Brief explanation of drawings]

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 shows the relationship between electrode thickness t2A and exposed surface W4 zone AR. Fig. 5 is a perspective view showing the dielectric layer spraying process in one embodiment of the present invention, Fig. 6 and Fig. 7 are graph diagrams showing the conventional manufacturing method. are also dielectric coated B4
' and each schematic cross-sectional view showing the formation mode of the dielectric layer 4, No. 8
9 and 9 are schematic cross-sectional views showing the adhesive 2b adhesion process and the amount formed, and FIGS. 10 and 11 are schematic cross-sectional views showing the electrode particle adhesion process and the amount formed, respectively. FIG. 12 is a schematic cross-sectional view showing the thick adhesive coating process, FIG. 13 is a schematic cross-sectional view showing the adhesive drying process, and FIG. 14 is a schematic cross-sectional view showing the electrode layer forming process. The schematic cross-sectional view shown in FIG.
A perspective view showing the is forming process, FIG. 16(a), FIG.
(b') Iiii [Developer carrier 11 similarly completed
Schematic side sectional view and front sectional view showing! '117 (a
) and FIG. 17(b) are respective explanatory diagrams showing the operation by the super finishing method, FIG. 18 is a schematic side sectional view showing a modified example of the completed developer carrier, and FIG. 19 FIG. 6 is an explanatory diagram showing a modification of the electrode layer forming process. (Explanation of symbols) 1: Conductive support 2': Electrode layer (before finishing) 2: Electrode layer (after finishing) 2a: Electrode particles 4: Dielectric layer 10: Super Finishing Units i~ Patent applicant Rico Co., Ltd. Masaaki Ichidai Masaaki Kohashi Figure 6 Figure 8 Figure 111 No. 1 Otsu 0 No. 121-! , 1 13th 171 141':! 1 9

Claims (1)

[Scope of Claims] 1. A method for producing a developer carrier comprising a large number of electrode particles on a conductive support, with a portion of each electrode particle exposed on the surface and kept electrically insulated from each other. , forming a dielectric layer made of a dielectric material on the conductive support; depositing a dielectric adhesive on the dielectric layer and depositing the electrode particles on the surface of the dielectric layer to cover the electrode layer; A method for manufacturing a developer carrier, comprising: a step of forming an electrode layer; and a surface processing step of applying a surface treatment to the surface of the electrode layer to expose a portion of each of the electrode particles to the surface. . 2. The method for producing a developer carrier according to item 1 above, wherein the surface treatment (1) is carried out by a super finishing method. 3. The developer according to the above item 1, wherein the application of the adhesive in the electrode layer forming step is carried out by dividing into a plurality of adhesive application steps with a drying step in between. Method for manufacturing a carrier.