JPS6053693B2 - Manufacturing method of elastic roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an elastic roller used in an image forming apparatus;
In particular, the present invention relates to a method of manufacturing an elastic roller whose outer peripheral surface is coated with a net-like material.

In image forming apparatuses such as diazo copying machines, electrophotographic copying machines, etc., which use a so-called developer, elastic rollers are installed at each of the above-mentioned parts as a means of development, liquid squeezing, cleaning, etc. It has been done using.

This type of elastic roller has a central rotation shaft circumferential surface.
One example is one in which only a foam member such as rubber foam or plastic foam or a cell member is provided with a uniform thickness. However, the following nine colors have been pointed out for such rollers.

That is, when the foam member directly contacts another rigid surface, the contact pressure and contact width of the nip portion due to the contact become non-uniform due to uneven hardness inside the foam member. Other problems include unevenness in the size of foam particles in foamed members or cellular members, and unevenness in the size and shape of pores on the surface. arise. For example, if this is used in a developing section, density unevenness will appear in the developed area of the image. Furthermore, during pressure contact, the surface of the elastic roller comes into close contact with the surface of the photoreceptor, and is also elastically deformed in the direction of the contact surface and moves in a direction other than perpendicular to the contact surface, which causes the developed image to rub and be disturbed. Sometimes. Separately, as an elastic roller that eliminates the above-mentioned drawbacks, for example, Japanese Patent Application Laid-Open No. 52-55644 discloses a structure in which a foamed elastic member having continuous pores is further covered with a flexible net-like material. Elastic rollers have been proposed.

Such an elastic roller rotates in pressure contact with the surface of a rigid member such as a photoconductor or an insulating member, forms a desired uniform nip, and squeezes out the liquid sufficiently absorbed inside the roller according to its elastic deformation. It has the effect of absorbing liquid, and conversely, it has the effect of absorbing liquid. Furthermore, since the elastic member does not come into direct contact with the photoreceptor, there is no inconvenience such as rubbing on the contact surface. Therefore, such elastic rollers are considered to be highly applicable to liquid developing sections for electrostatic images, aperture sections, and the like. However, in the case of this type of elastic roller having a net-like coating on its surface, it is important that the coating is evenly distributed over the entire circumferential surface of the roller, and that during its operation, for example, other stiffness It is necessary to process the inner circumferential surface of the net-like body so that it does not come loose from the internal elastic member and cause wrinkles in the net-like body when the net-like body is pressed against the surface and rotated. This is because the above-mentioned inconveniences remained. (b) When an elastic roller is used in the developing process, wrinkles on the surface cause uneven development.

Furthermore, if this is used for the purpose of removing excess developer, it may cause uneven squeezing of the solution. Furthermore, when used as a cleaning roller, it causes uneven cleaning and also causes uneven charging in the subsequent charging process.

By the way, methods for constructing such an elastic roller, that is, methods for covering the circumferential surface of the elastic roller with a net-like body, can be roughly divided into the following two types. Part 1
The first method is to stretch a cylindrical net-like body in advance to a diameter greater than the outer diameter of an elastic roller, insert the elastic roller into the inner space, and then return the net-like body to a predetermined diameter.

The other method is to insert an elastic roller into the inner space of a cylindrical mesh body with a predetermined inner diameter, compress it until the inner diameter of the mesh body is below the inner diameter of the mesh body, and then release the previous compression. It's a method.

However, in the former method, since the mesh is forcibly stretched out, it stretches and does not return to the predetermined diameter, making the diameter of the mesh uneven and causing wrinkles, waves, etc. There are inconveniences such as the elastic pressure becoming uneven on the circumferential surface of the elastic roller.

In addition, even with the latter method, when the elastic body is folded, there are inconveniences such as bends or twists in the axial direction of the elastic body, resulting in uneven elastic pressure on the circumferential surface of the elastic roller. is likely to occur.

Therefore, the main object of the present invention is to provide a new method for manufacturing an elastic roller having a mesh coating without causing such disadvantages.

More specifically, when covering an elastic body with a flexible net-like body, the elastic body and the net-like body do not undergo undesirable deformations such as wrinkles, corrugations, folds, twists, and burrs;
After the completion of the invention, it is an object of the invention to provide a new and improved method for producing elastic rollers whose properties are uniform over their entire circumference.

In addition, at least while satisfying the flexibility of the surface, it is possible to maintain uniform contact pressure at the nip and to allow sufficient liquid movement (absorption, squeezing) at the contact surface. It is another object of the invention to provide a new method for manufacturing elastic rollers.

Furthermore, even if the circumferential speed of the opposing rigid member does not completely match, or even if the rotating direction of the opposing rigid member does not match, the surface layer will not wrinkle and the wrinkles will increase. It is another object of the present invention to provide a new method for manufacturing elastic rollers that does not cause sagging. In short, the present invention achieves the above object by providing an elastic foam roller consisting of an axial roller and an elastic foam provided with a uniform layer thickness on the circumferential surface of the axial roller. covering said elastic foam roller with a cylindrical flexible mesh having an inner diameter larger than the diameter of said elastic foam roller, said elastic foam roller having an inner diameter larger than said outer diameter of said axial roller and an outer diameter less than or equal to the inner diameter of said mesh; inserting the elastic foam roller into the mesh body through the guide and releasing the compression of the elastic foam by the guide therein; , when the elastic foam is restored from the compressed state, it is pressed directly against the inner circumferential surface of the net-like body, and then, while applying tension in the axial direction of the elastic foam roller to the net-like body, This method of manufacturing an elastic roller is characterized in that a substantially uniform pressing force is applied to the outer circumferential surface of the roller and then released. Here, for the purpose of facilitating understanding of the following explanation, an outline of each element constituting the elastic roller according to the present invention will be explained using the drawings.

An example of the configuration of an elastic roller according to the present invention is schematically shown in FIGS. 1 and 2. In FIG. 1, an elastic roller 1 includes a shaft 2 made of a rigid body such as metal or hard synthetic resin, and an elastic foam 3 made of polyurethane foam or the like provided around the shaft 2.
, and a mesh body 4 covering the bubble body 3.

The foam 3 is fixedly attached to the shaft 2 by adhesive or the like, and the mesh 4 is compressed by the elastic repulsion force of the elastic foam 3 which is in a somewhat compressed state. When the central shaft 2 rotates, the bubbles 3 and the net-like body 4 can rotate together. Moreover, since the foam 3 has continuous pores that can be elastically deformed, it is possible to absorb and squeeze out liquid. The surface mesh 4 is a flexible mesh obtained by weaving or knitting fine stainless steel wires, natural fibers, synthetic fibers, etc., and the liquid flows through the weave of the mesh 4 to the bubbles 3. enter and leave. That is, when the elastic roller 1 impregnated with liquid is compressed, the liquid in the foam 3 is squeezed out from the weave part, and conversely, when the compressed and released foam 3 is restored, the mesh 4 The liquid on the surface of the bubble 3 is absorbed into the bubble 3 through the textured portion. Taking the field of application of such a roller as a developing roller for an electrophotographic copying machine, for example, the mesh value of the mesh member 4 is 1/300 mesh, which is suitable for use.

Further, in consideration of its liquid permeability, mechanical strength, chemical stability, etc., it is particularly preferable to use a fabric made of monofilament threads such as polyamide, polyester, polypropylene, polyether, vinylon, etc.

By the way, when a net-like body is used as in the example illustrated above, it is not only possible to use a plain weave, twill weave, or woven net, but also a pressurized deformation of the fabricated net may be used. Furthermore, the elastic roller according to the present invention can of course be modified in various other configurations.

That is, the outermost surface has a through hole that does not block the inside and outside of the elastic roller, and has flexibility in the vertical direction on the surface in contact with other rigid surfaces. However, any material may be used as long as the through hole on the contact surface is not blocked during contact. Therefore, the material for covering the outer circumferential surface of the elastic roller is not only the above-mentioned net, but also a thin metal plate or a resin film with a large number of holes as shown in the second illustrated example. It's fine. In FIG. 2, numeral 5 indicates a sleeve of such a perforated film, and the through holes are circular. By the way, the shape of the through hole is not limited to a circular shape, but may be a rectangular shape, an elliptical shape, a mosaic shape, or a combination thereof. Note that the foam 3 shown in FIGS. 1 and 2 is not limited to a single layer, but can also be configured to have multiple layers.

Further, the foam 3 can be made of a material that is capable of absorbing and squeezing out liquid through its deformation and exhibits appropriate elasticity.

For example, polystyrene, polyethylene, polyurethane,
Polyvinyl chloride, NBR (nitrile butylene rubber)
An elastic body made of natural, synthetic, or metal fibers is used. The central shaft 2 has the function of supporting the foam 3, and is generally made of metal such as aluminum or a rigid body such as plastic such as polyoxymethylene or polyamide.

In the above-described configuration, it is preferable that the central shaft 2 and the bubble 3 be bonded together.

On the other hand, it is preferable that the foam body 3 and the mesh body 4 are kept in a non-adhesive state. This is preferable because the effect of liquid absorption and squeezing by the bubbles 3 is greater. In the present invention, the components described above are assembled using the following method.

By the way, as mentioned above, in the method of the present invention, a tubular insertion guide capable of applying a uniform compressive force to the entire elastic foam roller before being coated with the mesh is used, and the above-mentioned After press-fitting an elastic roller, a guide is inserted into a cylindrical flexible net-like body, and when the roller is pulled out from the guide, a drag force is applied to the net-like body in the opposite direction to the direction in which the roller is pulled out. This was done so that the elastic body, which had been released from the compressive force, would use its restoring force to support the inner circumferential surface of the net-like body with a uniform elastic force, and at the same time add elasticity to the net-like body and cover it. The main feature is that the rollers are given more strain. below,
The manufacturing method of the present invention will be described in detail along with examples thereof with reference to the drawings. First, an elastic foam roller 6 (the cross section of which is shown in FIG. layer 8) and a polyester filament net (as an example, layer 8) as shown in FIG.
50 mesh) and a nickel-made vibrator-shaped insertion guide 10 whose cross section is shown in FIG. 5 are prepared.

At this time, the inner diameter of the net cylindrical object 9 is smaller than the outer diameter of the elastic foam roller 6, and the guide 10 has an inner diameter smaller than the outer diameter of the elastic foam roller 6, and the inner diameter of the mesh cylindrical object 9. It is formed to have a smaller outer diameter.

In addition to the guide 10 made of a rigid body such as metal, when the elastic foam roller 6 is press-fitted into the pipe,
Any material whose inner diameter does not change may be used, and for example, a flexible tube made of synthetic resin may be used.

Further, it is desirable to provide a tapered wide opening 10a at one end of the guide 10 as shown in the figure in order to facilitate insertion of the I elastic foam roller 6. It is convenient for the actual assembly process that this guide 10 has the same inner diameter portion 10b that is slightly longer than the length of the elastic foam roller 6 shown in the third figure. Further, the net tubular member 9 shown in the fourth figure is also slightly longer than the elastic foam roller 6 (several C7l).
) Prepare a longer one.

In addition to the above, in the method of the present invention, a rubbing vibrator 11 as shown in FIG. 6 is also used. This is the mesh cylinder 9
It is a metal vibrator that has an inner diameter slightly smaller than the outer diameter of the metal vibrator, and has a smooth inner peripheral surface. Note that this vibrator length is not particularly limited. Next, the method of the present invention is described below in FIG. 7A,
The process proceeds according to the steps illustrated in b, c, d, e, f, and g.

First, the aforementioned elastic foam roller 6 and insertion guide 10
and are arranged as shown in FIG. 7a. l Here, 12 is a fixing base of the insertion guide 10, and 14 is an elastic foam roller 6.
13 is a suitable pressurizing means having an air cylinder, a hydraulic cylinder, etc. used for press-fitting the elastic foam roller 6 into the insertion guide 10, and 13 is used to prevent the end portion of the elastic foam roller 6 from being damaged when it is press-fitted. It is a protective equipment used for By the way,
Such a protective device 13 is a device having a shape as shown in a plan view and a side sectional view in FIGS. It is made of a starfish-shaped thin plate made of a material with a large amount of water (for example, glass wool coated with Teflon).

Then, the fin 13a'' is inside the guide 10.
The shapes should be such that they do not overlap each other. Next, as shown in FIG. 7b, the elastic foam roller 6 pressed by the pressure means 14 is press-fitted into the insertion guide 10. At this time, the protector 13 prevents the entry side end of the elastic foam roller 6 from being pressed by the inner wall of the guide 10 and being damaged, or from being unnecessarily deformed. Further, the inner wall of the insertion guide 10 is preferably mirror-finished to a smooth surface so that the press-fitting can be performed smoothly without damaging the peripheral surface of the elastic foam roller 6.

In addition to this, it is further desirable to coat it with an anti-friction material such as Teflon or silicone. In this way, after the elastic foam roller 6 is press-fitted to the position shown in FIG. 7c, the protective device 13 is pulled out from the roller 6.

In the above steps, it is not necessarily necessary to cap the insertion guide 10 with the mesh tube 9. Although not shown in the illustrated example, it is also possible to proceed to the next step with the protective device 13 attached to the roller 6 as shown in FIG. 7c.

Next, a net cylindrical member 9 is mounted on the outer circumferential surface of the insertion guide 10 into which the elastic foam roller 6 has been press-fitted, so that its end protrudes slightly (several centimeters) from the lower end of the guide 10.

[...shown in Figure 7d] At this time, a part of the net cylindrical object 9 (...position 9a in the figure) is moved to the guide 10 by an appropriate means.
It is best to press it against the outer peripheral surface (to the extent that it can slide). Furthermore, it is also desirable to apply tension to the mesh tube 9 in the direction of the arrow in the figure. Thereafter, the elastic foam roller 6 is pushed out from the guide 10 in the direction of the arrow shown in the figure, using appropriate pressure means.

[...Fig. 7e] This extrusion is preferably performed all at once without changing the speed. If the extrusion speed is stopped midway or the extrusion speed changes significantly, the elastic foam will become distorted.
This is because the object of the present invention may not be fully achieved. Also, at this time, a part of the net cylindrical object 9 (9a in the figure) is pressed to the extent that it can slide against the outer peripheral surface of the insertion guide 10, and the elastic foam roller 6 is pressed against the net cylindrical object 9. It is also more effective to apply some tension in the opposite direction to the extrusion direction to prevent wrinkles from forming on the net.

In the illustrated process, when the tip of the elastic foam roller 6 is pushed out from the tip of the insertion guide 10, the compressive force that the elastic foam had been subjected to up to that point is released, so that the elastic foam is in its non-pressurized state. I will try to restore it to the same diameter.

Due to the elastic repulsive force of the elastic foam, the outer circumferential surface of the elastic foam roller 6 comes into close contact with the inner circumferential surface of the mesh tube 9 which has been set in advance at the position shown. Since a considerably large pressing force is applied to the contact surfaces between the two, there is no possibility of slippage between the two. Following this step, the roller that is pushed out while covering the net is passed through the inside of the squeezing vibe 11 while applying downward tension to the net.

[...Fig. 7f] In such a process, minute deformations that occurred in the net, elastic foam, etc. in the previous process can be completely corrected. When the entire elastic foam roller 6 is completely extruded from the vibrator 11 in this manner, the net cylindrical object 9 is uniformly covered without wrinkles on the circumferential surface, and the entire process of the present invention is completed. It has been completed.

[...Fig. 7g] In the present invention, as described above, by a relatively simple method, undesirable deformations such as wrinkles, corrugations, twists, and curls are caused in the net or elastic foam. It is possible to complete an elastic roller that has an almost uniform effect over its entire area.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are both perspective views shown to explain a configuration example of an elastic roller according to the present invention, and FIGS. 3 to 6 are respective configurations prepared for carrying out the present invention. Schematic diagrams for explaining parts; Figures 7A, b, c, d, e, f, and g are schematic sectional views for explaining the present invention in detail; Figure 8a is a protective equipment used in the present invention. A plan view illustrating one shape of the figure 8b.
is a sectional view of the gate side. In the figure, 1... elastic roller, 2, 7...
... Axis roller, 3, 8 ... Elastic foam, 4
, 9...Network, 6...Elastic foam roller, 10...Insertion guide, 11...
Vibrator for sex, 12...Fixed) stand, 13...
. . . Protective equipment, 14 . . . Pressurizing means.

Claims (1)

[Scope of Claims] 1. An elastic foam roller consisting of an axial roller and an elastic foam provided with a uniform layer thickness on its circumferential surface, with an inner diameter that is less than the outer diameter of the axial roller and larger than the outer diameter of the axial roller. covering said resilient foam roller with a tubular flexible mesh having an inner diameter greater than the outer diameter of said axial roller and an outer diameter less than or equal to the inner diameter of said mesh; inserting the elastic foam roller into the net through the guide and releasing the compression of the elastic foam by the guide; When restoring from the compressed state, it is directly pressed against the inner circumferential surface of the net-like body, and then, while applying tension in the axial direction of the elastic foam roller to the net-like body, approximately the outer circumferential surface of the net-like body is applied. A method for manufacturing an elastic roller, which comprises applying a uniform pressing force and then releasing it. 2. The method of manufacturing an elastic roller according to claim 1, wherein when applying tension to the cylindrical flexible net, at least a portion thereof is pressed against the outer circumferential surface of the insertion guide. 3. When applying a substantially uniform pressing force to the outer peripheral surface of an elastic foam roller covered with a mesh, the process is carried out by passing the roller through a cylindrical tube having an inner diameter slightly smaller than its outer diameter. A method for manufacturing an elastic roller according to scope 1. 4. The method of manufacturing an elastic roller according to claim 1, wherein the flexible net-like body has a larger overall length in its axial direction than the elastic foam roller. 5. The method of manufacturing an elastic roller according to claim 1, wherein the insertion guide is made of a rigid pipe. 6. The method for manufacturing an elastic roller according to claim 1, wherein the insertion guide has an identical inner diameter portion that is longer than the entire length of the elastic foam roller in its axial direction.