JPH0339613Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to improvements in rubber rollers used in paper feeding mechanisms, fixing mechanisms, and others of copying machines, printers, facsimile machines, and the like.

(Prior Art) Conventionally, rubber rollers have been used in paper feeding mechanisms and other mechanisms in copying machines, printers, facsimile machines, and the like. As shown in FIGS. 5 and 6, this rubber roller is formed of an outer cylinder 1 that comes into contact with an object to be contacted, and a columnar core metal 2 that is fitted into the outer cylinder 1. The outer cylinder 1 is made of a cylindrical elastic body so as to be pressed against an object to be contacted. However, with this conventional rubber roller, the contact force of the rubber roller to the contact object and the width of the axial contact with the contact object vary depending on factors such as the rotational runout of the roller, cylindricity, and flatness of the contact object. This causes variations, making it difficult to bring the rubber roller into uniform contact with the object. For example, in a paper feed mechanism, this causes a so-called paper jam, and in a fixing mechanism of a copying machine, it causes density unevenness.

Therefore, in the past, a plasticizer was mixed into the cylindrical elastic body to extremely reduce its hardness, for example, to JIS standard hardness (JISA/HS = 20 to 30°), and a rubber roller was brought into contact with the hardness. Previously, jams and uneven rotation were prevented by applying force in the direction of contact with the object to maximize the width of axial contact with the object and applying contact pressure to the object. Depending on the method, plasticizer bleed, so-called blow-out, may cause paper to wrap around the rubber roller used in the paper feed mechanism, and toner may stick to the rubber roller used in the fixing mechanism. If the rubber roller is brought into contact with the contact object while applying contact pressure, the rubber roller will be distorted and rotate unevenly, and there will be problems such as an increase in the rotational torque of the rubber roller.

Therefore, as a means to improve the elastic modulus of the cylindrical elastic body of the rubber roller, it may be possible to reduce the thickness of the outer layer by forming the outer cylinder with a two-layer structure consisting of sponge rubber on the inside and solid rubber on the outside. The size and characteristics of the rubber roller tend to vary due to variations due to foaming of the sponge rubber, and adhesion between the sponge rubber and the solid rubber requires skill, which complicates the manufacturing process of the rubber roller and increases costs. It has a defect.

(Purpose of the invention) The present invention was devised in consideration of the above circumstances, and its purpose is to provide a simple solution without changing the hardness or thickness of the cylindrical elastic body that constitutes the outer cylinder. To provide a rubber roller capable of surely bringing an outer cylinder into contact with an object to be contacted.

(Structure) The feature of the present invention is that the columnar core metal is composed of a pair of columnar split core metals that are divided at their axial middle portions, and an elastic core is provided between the pair of columnar split core metals facing each other. It's where you are.

(Example) Below, an example of the rubber roller according to the present invention will be described based on the drawings.

In FIG. 1, 3 is an outer cylinder. This outer cylinder 3
is made of a cylindrical elastic body. This outer cylinder 3
A columnar core bar 4 is fitted into the columnar core bar 4 . This columnar core metal 4 is divided into two parts from its axial center, and is composed of split core metals 5 and 6. This split core metal 5,
6 integrally have journal portions 7 and 8, respectively. The journal portions 7, 8 are supported by bearings (not shown). The rubber rollers are rotated around the axes of the journal parts 7 and 8.

An elastic core portion 9 is provided between the split core metals 5 and 6 facing each other. This elastic core portion 9 has a function of urging the outer cylinder 3 toward the outside. This elastic core 9
is considered to be a cylinder. Is the material of the elastic core portion 9 the same as that of the cylindrical elastic body constituting the outer cylinder?
Alternatively, it is preferable to use a material having a slightly higher elasticity than that of the material of the cylindrical elastic body. Further, in consideration of static electricity generated in the outer cylinder 3, the elastic core 9 may be made of a conductive material. If this elastic core member 9 is electrically conductive, the outer cylinder 3
Static electricity generated in the central portion of the decomposition core metals 5 and 6 can be removed through the decomposition core metals 5 and 6. Furthermore, when applying voltage to the split core bars 5 and 6 or when uniformity of the electrical characteristics (permittivity, resistance value) in the axial direction of the rubber roller is required, the elastic core portion 9 may be made of a conductive material. This is possible by using different materials. The end face 10 of the elastic core portion 9 is configured to be perpendicular to the axis of the outer cylinder 3, but as shown in FIG. On the other hand, it may be formed obliquely into an elliptical shape, so that the end surface 10 of the elastic core portion 9 is oblique with respect to the axis of the outer cylinder 3. According to the embodiment shown in FIG. 2, the axial length of the elastic core 9 provided in the central portion of the outer cylinder 3 can be made substantially long, so that the rubber roller contacts the The width of the axial contact can be made larger than that of the first embodiment. Furthermore, according to the second embodiment, even if the distance between the opposing split core bars 5 and 6 is made smaller than that of the first embodiment, the same axial contact as that of the first embodiment can be achieved. This means that a contact width can be given to the outer cylinder 3, and the concentricity and flexibility of the rubber roller can be made substantially the same as those of conventional rubber rollers.

For example, in the case of a conventional rubber roller with a hard bottom or a thick wall, when it is polished as shown in FIG. 3, both end face portions 11 escape from the polished surface, resulting in polishing residue. Even if a biasing force is applied to the rubber roller in the direction of contacting the contact object 12 such as paper or a facing rubber roller, the intermediate portion 1
3 may float and the outer cylinder 1 may not come into contact with the contact object 12, resulting in a jam during paper feeding and omission of the transferred image during the transfer process. According to the rubber roller,
Even if there is polishing residue on both end surfaces 11, since the columnar core bar 4 is divided into parts and the elastic core part 9 is provided in the center, a rubber roller can be attached in the direction of the arrow as shown in FIG. If the force is applied, the outer cylinder 3 on either side of the intermediate portion will come into contact with the contact object 12, and the intermediate portion 1 caused by polishing residue will be removed.
3 can be prevented from floating, and the contact object 12 can be reliably brought into contact.

(Effects of the invention) As explained above, the present invention consists of a pair of columnar split core metals that are split at the axially intermediate portion thereof, and an elastic force between the opposing columnar split core metals. Since a core is provided and the elastic core is used to impart elastic force to the outer cylinder, the structure can be simplified without changing the hardness or thickness of the cylindrical elastic body that makes up the outer cylinder. This has the effect that the outer cylinder can be reliably brought into contact with the object to be contacted.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a second embodiment of the rubber roller according to the present invention, FIG. 2 is a longitudinal sectional view showing the second embodiment of the rubber roller according to the present invention, and FIG. An explanatory diagram for explaining the disadvantages of the conventional rubber roller in comparison with the advantages of the rubber roller according to the invention, FIG. 4 illustrates the advantages of the rubber roller of the invention in contrast to the disadvantages of the conventional rubber roller shown in FIG. FIG. 5 is a side view showing the structure of a conventional rubber roller, and FIG. 6 is a longitudinal sectional view showing the structure of the rubber roller shown in FIG. 3...Outer cylinder, 4...Column-shaped core bar, 5, 6...Split core bar, 9...Elastic core portion, 12...Contact object.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a rubber roller in which the outer cylinder that comes into contact with an object to be contacted is formed of a cylindrical elastic body, and a columnar core serving as a central shaft is fitted into the cylindrical elastic body. , A rubber roller characterized in that the columnar core metal is constituted by a pair of columnar split core metals divided at an axially intermediate portion thereof, and an elastic core portion is provided between the pair of columnar split core metals facing each other. . (2) The rubber roller according to claim 1, wherein the elastic core is made of the same material as the cylindrical elastic body constituting the outer cylinder.