JPS62215984A - Elastic roller and fixing device using elastic roller - Google Patents

Abstract

PURPOSE:To obtain an elastic roller of low hardness by providing plural holes extending in the axial direction, on an elastic layer, placing them so that the radius penetrates one of the holes, pressing the roller against a driven side, driving the other, and rotating the roller in the direction where an inclination of a support wall increases. CONSTITUTION:An elastic layer 1 has a support 3 extending to the outside from a cylindrical base layer 2 which contacts a mandrel 26, and a surface layer for connecting the support 3, the support 3 is placed equally in the peripheral direction, extends in parallel to a mandred axis, and a hole 5 is made. The support 3 is inclined by an angle alpha against a radius 6, and thickness (t) is determined suitably so as to obtain a desired hardness. An elastic roller 10 is pressed against a fixing roller 20, drives it, rotates in the direction where an inclination of a support wall increases, and an optional radius 7 always penetrates the hole 5. At the time of a size and a shape of the hole 5 are selected, an elastic roller of a low hardness and a desired value is obtained, and its value is uniform in any position.

Description

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

(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 the case of such an elastic roller, it is desirable that it is easily elastically deformed and has a large contact area, and that the contact pressure is nearly uniform at any position within that range. For example, as an elastic roller that rotates at a constant speed, the contact pressure must remain constant over time. Examples include a pressure roller of a fixing device in a copying machine and a cleaning roller for a photoreceptor.

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. On the other hand, in the case of a roller with a sponge inside, the sponge is formed by foaming, but it is difficult to make the dimensional stability, hardness, foam density, porosity, and foam structure uniform, and the elasticity This has an adverse effect on the uniformity of the roller properties. Therefore, it was considered to make a normal elastic rubber roller into a single 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 hardness and the area of the support wall between the adjacent holes, and this appears as unevenness in the roller properties. However, this has caused problems in the fixing characteristics, and there has been a demand for improvement of the elastic roller.

(Means for Solving the Problems) The present invention solves the above-mentioned problems, and provides an elastic roller that has low hardness, constant contact within the range of contact with the other party, and excellent durability, and a fixing roller that uses the elastic roller. The purpose is to provide a device, which consists of the following:

The present invention relates to the above-mentioned elastic roller, in which an elastic layer is integrally formed with an elastic material in a cylindrical shape around a shaft-shaped core metal member, and a part of the elastic layer is elastically deformed to form a cylindrical elastic layer. In the elastic roller that is brought into pressure contact, a plurality of holes are formed in the elastic layer and divided at equal intervals in the circumferential direction by support walls that extend in the axial direction and are inclined with respect to the radial line. An arbitrary radius line is formed so as to always pass through one of the holes, and is in pressure contact with the other party, which is the driven side, and rotates in a direction in which the inclination of the support wall increases while driving the other party. As for the fixing device using the elastic roller, the fixing device includes a plurality of rollers in contact with each other, and at least one roller is elastically deformed by pressure contact to form a pressure contact area for fixing. In the above, the elastic roller has a cylindrical elastic layer made of an elastic material formed integrally with the core metal member around the axial core metal member, and the elastic layer has a cylindrical elastic layer that extends in the axial direction. And with respect to the radius line (a plurality of holes are formed that are divided at equal intervals in the circumferential direction by the oblique support wall, and the holes are arranged so that any radius line always passes through one of the holes). It is characterized by being in pressure contact with a mating roller on the driven side and rotating in a direction in which the inclination of the support wall increases while driving the mating roller.

(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 in use, and FIG. 3 is a side view of the elastic roller as another embodiment.

As shown in FIGS. 1 and 2, the elastic roller 10 of this embodiment has an elastic layer 1 arranged in a cylindrical shape around a shaft-shaped core member 26.
is integrally molded with the core metal 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 member N1 is integrally formed with the core member 26 except for the ends 26A and 26B.

The elastic layer 1 includes a cylindrical base layer portion 2 formed in contact with a core member 26, a plurality of support walls 3 extending radially outward from the base layer portion 2, and each support wall 3. It consists of a cylindrical surface layer part 4 in which . The support walls 3 are arranged at equal positions in the circumferential direction and extend approximately parallel to the core member 26 in the axial direction. Thus, a plurality of holes 5 are formed by the support wall 3, the outer surface of the base layer portion 2, and the inner surface of the surface layer portion 4, which are parallel to the core metal member.

In this embodiment, the support wall 3 is set asymmetrically with respect to the radius line 6 of the elastic roller 10 by having an inclination angle α to the radius line 6 of the elastic roller 10, as shown in FIG. An arbitrary radius line, for example radius line 7 in the figure, is formed so as to always pass through the hole 5 at any corner. The inclination angle α and the thickness t of the support column 3 are basically determined relative to each other so as to satisfy the above conditions. Together with the thickness, the value is determined to provide the desired hardness for the elastic roller.

When the elastic roller 10 as described above is used, for example, as a fixing roller as shown in FIG. The roller 20 on the driven side is rotated. The rotation direction A of the elastic roller 10 on the driving side is such that when the elastic roller is elastically deformed by pressure contact, the support wall 3
This is a direction in which the inclination angle α of .

In this embodiment, when the elastic roller comes into contact with the mating roller, the support wall 3 tends to bend because it is inclined, and the force received from the mating roller on the driven side is applied to the support wall 3. This acts in a direction that makes the roller more inclined, making it easier to deform the roller as a whole.Moreover, since the holes are arranged so that the radius line 7 at any angle always passes through one of the holes 5, which direction in the circumferential direction The degree of deformation is approximately the same regardless of the position, and the surface layer portion 4 having a constant thickness further equalizes the degree of deformation in the circumferential direction. Moreover, even in such a state, the surface layer portion 4 maintains a predetermined surface strength.

In this embodiment, the holes 5 have a deformed trapezoidal shape as shown in FIG. 2, but they may have other shapes as shown in FIG. 3 as another embodiment.

FIG. 3 is another example showing other possibilities regarding the shape of the holes. In Figure 2, the support wall is continuous and sloped with a nearly constant thickness, but the support wall does not necessarily have to be continuously sloped, and may be stepped in stages as shown in Figure 3. It only needs to be substantially inclined. In the figure, the mating roller is omitted and only the elastic roller IOA is shown.

The support wall 3A is bent in a crank shape, and the holes 5A are also crank shaped accordingly. The support wall 3A is inclined as a whole by an angle α on average with respect to the radius line 7.

Therefore, when the elastic roller of this embodiment rotates in contact with the roller on the driven side in the same direction as the one in FIG. 2, it is more likely to deform, and the deformation is almost uniform in the pressure area. .

The performance of the elastic roller obtained in the above example was confirmed by using it as a drive-side roller in a fixing device such as a copying machine, 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 cylindrical aluminum core material with an outer diameter of 25 mm and a wall thickness of 1.4 mm, and a fluororesin coating is applied on the circumferential surface of the cylindrical aluminum core material for approximately 25 mm.
A halogen heater 1.1 is provided as a heating element 42 inside the fixing roller 40, and a temperature detection sensor 41 is provided on the circumferential surface of the fixing roller.
An NTC thermistor is brought into contact with the fixing roller 40 to control the temperature so as to maintain the outer peripheral 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 made of stainless steel with an outer diameter of 10 mm, has a cross-sectional shape as shown in FIG. A roller having a lotus stem-like elastic layer and a hardness measured at the surface layer of the roller having a hardness of 27° (measured under a constant load of 300 g of Asker C) is used.

The pressure roller 45 is driven to rotate in the direction of arrow A at a circumferential speed of 66 mm/s by a drive device (not shown), and the fixing roller 40 rotates following the pressure roller 45. 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 . When this fixing device was used to fix A4 size paper (80 g/n) containing unfixed toner images at a frequency of 8 sheets per minute, good fixing performance was obtained, and it was possible to fix 200,000 sheets of paper of the above size. Even after the fixing process, stable fixing performance is obtained without wrinkles or uneven fixing, and its durability is also guaranteed.
It was done.

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 photoconductor, etc. can be mentioned.

(Effects of the Invention) As described above, the present invention provides a plurality of holes extending in the axial direction in the elastic layer by inclined support walls, arranges the holes so that an arbitrary radius line passes through any of the holes, and Since the rotational force is applied from the other side in the direction in which the angle of inclination of the support wall increases, an elastic roller with extremely low hardness and a desired value can be obtained by selecting the size and shape of the holes, etc. Moreover, the above value of the elastic roller is uniform no matter where it is located. As a result, the functions of the device using the elastic roller are 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.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is an external perspective view of an elastic roller as an embodiment, FIG. 2 is a side view of the elastic roller of FIG. 1 in pressure contact with a counterpart roller, and FIG. FIG. 3 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 3.3A...Strut wall 5.58...Vacancy

Claims (2)

[Claims] (1) In an elastic roller in which a cylindrical elastic layer of an elastic material is integrally molded around a shaft-shaped core metal member, and a part of the elastic layer is elastically deformed to press against the other party. , A plurality of holes are formed in the elastic layer, which are partitioned at equal intervals in the circumferential direction by support walls that extend in the axial direction and are inclined with respect to the radial line. An elastic roller, which is formed so as to pass through any of the holes, and rotates in a direction in which the inclination of the support wall increases while coming into pressure contact with a counterpart on the driven side and agitating the counterpart. (2) In a fixing device comprising a plurality of rollers pressed against each other, at least one of which is elastically deformed by pressure contact to form a pressure contact area for fixing, the elastic roller has a shaft-shaped A cylindrical elastic layer made of an elastic material is formed around the core member and integrally formed with the core member, and the elastic layer includes a support wall that extends in the axial direction and is inclined with respect to the radius line. A plurality of holes are formed at equal intervals in the circumferential direction, and the holes are formed such that an arbitrary radius line always passes through one of the holes, and is in pressure contact with the other roller on the driven side. The fixing device is configured to rotate in a direction in which the inclination of the support wall increases while driving the other roller.