JPS62251517A - Elastic roller - Google Patents

Abstract

PURPOSE:To obtain uniform elasticity values as desired in an elastic roller of a copying machine or the like, by providing an elastic layer with a plurality of holes, two or more of which are penetrated with any radius-line at the same time, and making the dimension of the hole in the radial direction be larger than the thickness (=0.3mm) of the surface layer part. CONSTITUTION:An elastic layer 1, which is formed on a core metal member 26, consists of a base layer 2, a hole layer part 3, in which holes 5 are formed in the axial direction by means of a plurality of strut parts 3A extending diagonally outward in the radial direction, and a surface layer part 4 whose thickness is 0.3mm or greater. An angle of inclination alpha and thickness t of the strut parts 3A are determined in such a manner that there exist at least two of the holes 5 to any radius-line 6 or 7. In addition, the sum B (=B1+B2) of B1 and B2, both of which are the length measured along a radius-line, is set so that B is greater than that the thickness A of the surface layer 4. With this contrivance, very low hardness as desired can be obtained uniformly over the peripheral surface of the elastic roller, thereby enhancing the durability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an elastic roller that elastically contacts a counterpart.

(Prior Art and Problems) When an elastic roller comes into pressure contact with an opponent, it is required to elastically deform at the contact portion. In many cases, such elastic rollers are desired to be easily elastically deformed, have a large contact area, and have nearly uniform contact pressure at any position within that range. Further, such an elastic roller may be rotating at a constant speed, and in this case, the contact portion moves, but it is required that the contact pressure is always constant over time. For example, examples of elastic rollers that rotate at a constant speed include a pressure roller of a fixing device in a copying machine, a cleaning roller for a photoreceptor, and examples of elastic rollers that are used in a non-rotating state include a platen roller.

Conventionally, elastic rollers for the above-mentioned applications include rollers in which the elastic layer formed around the core metal member serving as the shaft is solid, for example, made of a single material, and the material itself is low hardness rubber, or rollers with a surface layer A roller with a rubber layer of a certain hardness and a sponge between it and a cored metal was used. However, in the case of the single solid low hardness rubber roller mentioned above,
When used for a long time, the strength and strength of the material decrease due to its own weakness.
It is known that durability deteriorates, and there is a limit to this. In the case of a roller having a sponge in one direction, the sponge is formed by foaming, but it is difficult to make the dimensional stability, hardness, foam density, porosity, and foam structure uniform. This adversely affects the uniformity of the characteristics of the elastic roller. Therefore, it was considered to make a normal elastic rubber roller into a lotus stem structure with holes parallel to the core metal member without using the above sponge, but an appropriate structure was not developed and the hole area A difference in hardness occurs between the support region between the adjacent holes, and this appears as unevenness in the roller properties, causing problems in the properties of devices using elastic rollers. It had been requested.

(Means for Solving the Problems) An object of the present invention is to solve the above-mentioned problems and provide an elastic roller with low hardness, constant contact within the range of contact with the other party, and excellent durability. It is structured as follows.

The present invention provides an elastic roller having a cylindrical elastic layer made of an elastic material around a shaft-shaped core member, wherein the elastic layer comprises a base layer portion, a hole main portion, and a cylindrical elastic layer formed in sequence around the core member. A hole is formed in the main part of the hole so that an arbitrary radius line of the elastic roller passes through two or more holes, and one surface peripheral part has a thickness of 0.3w. The present invention is characterized in that the radial dimension of the pores is larger than the thickness of the surface layer.

The pores in the pore layer can be formed so as to exist on two sides of the radial force, but in such a case, the total size of the pores along the radial line is greater than the thickness of the surface layer.

Further, when the elastic roller is required to have uniform and good thermal conductivity, such as a fixing roller of a copying machine, the thickness of the surface layer portion is preferably 2 fl or less.

(Example) Hereinafter, the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a perspective view of an elastic roller according to one embodiment of the present invention, FIG. 2 is a side view of the elastic roller, and FIG. 3 is a side view of an elastic roller according to another embodiment.

As shown in FIGS. 1 and 2, in the elastic roller of this embodiment, a cylindrical elastic layer 1 is integrally formed around a shaft-shaped core member 26.

The core member 26 has a cylindrical shape, and stepped end portions 26A and 26B are provided at both ends to be rotatably supported when used as an elastic roller.

The elastic layer 1 is integrally formed with the core member 26 except for the ends 26A and 26B.

The elastic layer 1 is made of an elastic material such as synthetic resin or rubber, and includes a cylindrical base layer 2 formed in contact with a core member 26, a hole main portion 3 provided thereon, and an outer skin. It consists of a surface layer portion 4. In the above-mentioned hole main portion 3, holes 5 are provided by a plurality of support portions 3A extending radially outward from the base layer portion 2. The support columns 38 are arranged at equal positions in the circumferential direction and extend substantially parallel to the core member 26 in the axial direction. Thus, by the above-mentioned support section 3A, the outer surface of the base layer section 2, and the inner surface of the surface layer section 4,
A plurality of holes 5 are formed parallel to the cored metal member.

The above-mentioned support portion 3A is the radius line 6 of the elastic roller as shown in
The holes 5 are set asymmetrically with respect to the radius line 6 by having an inclination angle α to It is formed so as to penetrate through the holes 5 described above. In this embodiment, two holes 7 are penetrated as shown in FIG.

The inclination angle α and the thickness t of the support column 3A are basically determined relative to each other so as to satisfy the above conditions, but in actual design, the base layer 2 and the surface layer are Together with the thickness of the portion 4, the hardness is set to a value that provides the desired hardness for the elastic roller.

In the elastic layer as described above, the thickness of the surface layer 4 is 0.3
ms or more, and the dimension along the radius line of the hole 5 is also large in the thickness of the surface layer portion. As in the present embodiment shown in FIG. 2, even though there is only one hole 5 in the radial direction, since the support portion 3^ is inclined, any radius line 7 may have two or more holes. 5, the total dimension B along the radius of the hole, that is, B1+82, is set to be larger than the thickness A of the surface layer portion.

In this embodiment, the holes are arranged so that when the elastic roller comes into contact with the other party, the radius line 7 at any angle always passes through two or more holes 5. Therefore, the degree of deformation is almost the same in the nip section at any position in the circumferential direction, and since the dimension along the radius of the hole 5 is larger than the thickness of the surface layer and is ensured sufficiently, the support column is easy to flex and the entire roller is As such, it is easily deformed. Furthermore, in the case of Fig. 2, since the support section 38 is inclined,
More easily deformed. Furthermore, the surface layer portion 4 having a constant thickness further makes the degree of deformation in the circumferential direction more uniform, and there is no difference in the degree of deformation between the vicinity of the hole and the vicinity of the support portion.

Moreover, even in such a barking state, the surface layer portion 4 maintains a predetermined surface strength.

As a result of testing various sizes of elastic rollers as described above, we found that the lower limit of the surface layer was 0.3 mm, which was not significantly influenced by the outer diameter of the elastic roller or the material of the elastic layer. It was confirmed that it was number 1. For example, when used as a fixing roller in a copying machine, it has been found that if the thickness of the surface layer is 0.3 mm, no deterioration in fixing performance such as uneven fixing or wrinkles will occur as described later.

Furthermore, when an elastic roller is used as a fixing roller in a copying machine, uniform and good heat conduction is required, and to satisfy this requirement, it is desirable that the thickness of the surface layer be 21) or less This has also been confirmed.

FIG. 3 is another embodiment showing other possibilities regarding the shape and arrangement of the holes. In the figure, each hole has a substantially rectangular shape and is symmetrical with respect to a radius line. The holes are arranged radially in the inner hole 8. intermediate hole 9 and outer hole 10
They are lined up in three rows, and the holes in each row are 8.9.10.
are arranged so that a radius line 1) at an arbitrary corner position passes through at least two or more holes. Even in such a case, the sum B of the radial dimensions of the holes 8.9.10, that is, I1) + 82 + 83, is larger than the thickness A of the surface layer, as in the case of Fig. 2. .

In this example, since the number of holes increases with the number of rows,
The elastic roller is easily deformed, and its deformation characteristics are almost the same everywhere.

The performance of the elastic roller obtained in the above example was confirmed by using it in a fixing device of a copying machine, etc., and specific numerical values are shown here. FIG. 4 is a schematic sectional view of the heating roller fixing device.

The fixing roller 40 has a fluororesin coating on the circumferential surface of a cylindrical aluminum core material with an outer diameter of 25 mm and a wall thickness of 1.4 mm.
Inside the fixing roller 40, a halogen heater of -1.1 is provided as a heating element 42, and an NTC thermistor is brought into contact as a temperature detection sensor 41 on the circumferential surface of the fixing roller. The temperature is controlled to maintain the outer circumferential surface of the fixing roller 40 at approximately 180°C.

An elastic roller of the present invention is in opposing pressure contact with the fixing roller 40 as a pressure roller 45 with a total pressure of about 6 kg. This pressure roller 45 is placed on a stainless steel core material with an outer diameter of 10 mm.
With the cross-sectional shape shown in Figure 2 or Figure 3, a lotus-like elastic layer with an outer diameter of 24 fins, an effective circumferential length of 230 mm, and a flesh of W1 am is provided, and the hardness measured at the surface layer is 27 (Asker-030).
A roller of 7 measurements is used for a constant load of 0g.

The pressure roller 45 is supported by a drive device (not shown) so as to be able to follow the fixing roller 40, which is rotationally driven in the direction of arrow a at a circumferential speed of 66 m5/s. At the pressure contact portion between both rollers, a fixing process is performed by heating and pressurizing the recording material 51 having the toner image 52 made of resin or the like while nipping and conveying the recording material 51 . Such a fixing device fixes A4 size paper (
80g/rrr) at a frequency of 8 sheets per minute, good fixing performance was obtained, and even after fixing 200,000 sheets of paper of the above size, no wrinkles or uneven fixing occurred. Stable fixing performance was obtained and its durability was also confirmed.

The elastic roller shown in this embodiment can be widely used as a general elastic roller, and examples of its use include not only the pressure roller of a fixing device in a copying machine as described above, but also a cleaning roller for a photoreceptor, Alternatively, a tS feeding roller, a platen roller, etc. may be used.

(Effects of the Invention) As described above, the present invention provides a plurality of holes extending in the axial direction in an elastic layer, and arranges the arbitrary radius line to penetrate two or more holes, thereby reducing the thickness of the surface layer. Since the diameter of the holes is 0.3 mm or more and the radial dimension of the holes is larger than the thickness of the surface layer, an elastic roller with extremely low hardness and a desired value can be obtained by selecting the size and shape of the holes. Moreover, the above value of the elastic roller is uniform no matter where it is applied. As a result, the functionality of the device using the elastic roller is further improved, the durability of the elastic roller is extended, and the maintenance effort of the device is reduced, which greatly contributes to cost savings.
This brings about this effect.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an embodiment of the present invention, and FIG. 1 is an external perspective view of an elastic roller as an embodiment, FIG. 2 is a side view of the elastic roller shown in FIG. 1, and FIG. 3 is a side view of the elastic roller shown in FIG. 4 is a side view of an elastic roller of another embodiment, and FIG. 4 is a schematic diagram showing an example in which the elastic roller of the above embodiment is used as a pressure roller of a fixing device. 1......Elastic layer 2...
・・・・・・・・・Base layer part 3・・・・・・・・・・・・
...Vacancy main part 4...Surface layer part 5:8.9.10...Vacancy 6.7;1)... ...Radius line 26...
......Core member patent applicant
Canon Co., Ltd. Representative Patent Attorney Toru Fujioka Figure 1

Claims (3)

[Claims] (1) In an elastic roller having a cylindrical elastic layer made of an elastic material around a shaft-shaped core member, the elastic layer includes a base layer portion, a porous layer portion, and a hole layer portion formed sequentially around the core member. In the porous layer part, holes are formed such that an arbitrary radius line of the elastic roller passes through two or more holes, and the surface layer part has a thickness of 0.3 mm or more. , and the radial dimension of the holes is larger than the thickness of the surface layer. (2) Two or more pores exist in the radial direction in the pore layer,
The elastic roller according to claim 1, wherein the total size of the holes along the radius line is larger than the thickness of the surface layer. (3) The elastic roller according to claim (1) or (2), wherein the surface layer portion has a thickness of 2 mm or less.