JPH0128520Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat fixing device equipped with a heat fixing roller, which is used in copying machines and the like.

Such a heat fixing device has a pair of rollers placed in pressure contact with each other, at least one of the rollers is heated, a copy sheet on which a toner image has been formed is passed between the rollers and heated, and the toner image is transferred to the copy sheet. This is to make it take root.

In this heat fixing device, the heated roller is
Since it is rotatably supported by the device body via a bearing, the heat of the roller is dissipated via the bearing, which slows down the rise in temperature at both ends of the roller, and by extension the rise in temperature of the entire roller as desired. There was a drawback.

A device that improved this was published in Utility Model Application No. 118351/1983.
This has already been proposed in Utility Model Application Publication No. 50-93154 and Utility Model Application Publication No. 51-66442.

However, in all of the devices described in the above publications, a heat insulating material is interposed between the bearing and the roller body including the roller core metal, so that the heat of the roller is transferred from the end face of the core metal or from the core metal to the bearing. The structure is complicated, and when implementing this, there is a problem that it increases the cost.

The present invention prevents the heat of the fixing roller from dissipating through the bearing by providing at least one circumferential groove on at least one of the outer circumferential surface of the core metal of the fixing roller and the inner circumferential surface of the bearing. can,
It is an object of the present invention to provide a heat fixing device with a simple structure.

An embodiment of the present invention will be described below with reference to FIG.

The heating fixing roller 2 has a heating source 1 installed inside.
Both ends thereof are rotatably supported by an immovable support plate 3 via bearings 4 (the figure shows how one end is supported, and the other end is omitted). Heat fixing roller 2
is a hollow core metal 12 made of a rigid body, and its core metal 1
An elastic layer 22 made of an elastic material such as rubber on the circumferential surface of the
It is formed from. Both ends 12a (only one is shown) of this core metal 12 are connected to an immovable support plate 3 through rolling bearings 4 such as ball bearings.
is supported by A driving gear 5 is fixed to one end of the end 12a of the core metal 12.

Inside the fixing roller 2, a heat source 1 composed of a heater or the like is provided. In the figure,
Reference numeral 11 indicates a terminal for supplying current to the heating source.

A circumferential groove 32 is provided on the outer circumferential surface 12b of the core metal 12 of the fixing roller that fits into the bearing.
is provided. A non-circumferential groove portion 12c of the outer circumferential surface 12b of the metal core end is in contact with and fitted into the inner circumferential surface 4a of the bearing inner ring constituting the bearing 4, and the bottom portion 32a of the circumferential groove and the inner circumferential surface 4a means that a gap is maintained.

Since the present invention has the above-described configuration, the heat from the heating source 1 is transmitted to the core bar 12, and further transmitted from the core bar 12 to the elastic layer 22, so that the heat is transferred to the fixing roller 2.
is heated. At this time, the heat transferred to the core metal 12 is also transferred from the end 12a of the core metal 12 to the bearing 4 that is in contact with it. However, since the circumferential groove 32 is formed in the fitting portion between the outer circumferential surface 12b of the end portion 12a and the inner circumferential surface 4a of the bearing 4, the amount of heat transferred to the bearing 4 is reduced.

Therefore, the presence of the circumferential groove 32 suppresses wasteful heat radiation, and the rise in temperature of the roller 2 is accelerated by the suppressed amount. In addition, suppressing heat radiation from both ends of the core bar means that variations in the temperature distribution in the axial direction of the heating fixing roller 2 are reduced, which is also effective in maintaining uniform fixing performance. It is.

Since the present invention has the above-described configuration, the heat of the heated fixing roller 2 is not transmitted from the circumferential groove 32 to the bearing 4. Therefore, the bearing 4 and the support plate 3 connected thereto are not heated and expansion due to heat does not occur in them, and there is no possibility that their support of the fixing roller 2 will be hindered. Furthermore, the present invention enables heat dissipation by simply providing a groove on the outer circumferential surface of the core metal 12 without interposing another member such as a heat insulating material between the bearing 4 and the roller body including the roller core metal 12. It can be prevented. Therefore, the present invention can prevent heat dissipation with a much simpler mechanism than conventional fixing devices. In other words, the fixing device can be configured at low cost. In this embodiment, a circumferential groove 3 is formed on the outer circumferential surface 12b of the core metal of the fixing roller.
2 has been shown, however, in the present invention, a circumferential groove may be provided on the inner circumferential surface 4a of the inner ring of the bearing.

Next, another embodiment of the present invention will be described based on FIGS. 2 to 4. The same members as in the above embodiment are given the same reference numerals, and their explanations will be omitted. In the above embodiment, an example was shown in which the fixing roller 2 was rotatably supported by the rolling bearing 4, but in the present invention, as shown in FIG. A fixing device supported rotatably may also be used. In this case as well, it goes without saying that the circumferential groove 32 may be provided not only on the outer circumferential portion 12b of the core metal but also on the inner circumferential surface 24a side of the bearing 24 as in the above embodiment. Moreover, as shown in FIG. 3, the present invention is not limited to one circumferential groove 32, but a plurality of circumferential grooves 32, 32 are provided on the outer circumferential surface of the core metal and/or on the inner circumferential surface of the bearing. Good too.

In each of the above embodiments, the non-circumferential groove portions 12c, 12c' on both sides of the circumferential groove 32 are located on the inner circumferential surface of the bearing.
However, in the fixing device of the present invention, as shown in FIG.
c' does not have to be a contact fit.

In the fixing device of the present invention, regardless of whether one of the non-circumferential groove portions 12c, 12c' sandwiching the circumferential groove 32 contacts the inner peripheral surfaces 4a, 24a of the bearings 4, 24, or both contact, The degree of fitting between the bearings 4 and 24 and the core metal 12 at the portions where they directly contact each other is appropriately set in consideration of the support strength of the fixing roller 2 and the heat dissipation effect.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of a heat fixing device according to the present invention, and is a longitudinal sectional view of one end of a heat fixing roller, and FIG. 2 shows an end of a heat fixing roller showing another embodiment of the present invention. FIG. 3 is a vertical sectional view of one end of a heat fixing roller showing still another embodiment of the present invention, and FIG. 4 is a longitudinal sectional view of one end of a heat fixing roller showing still another embodiment of the present invention. It is a front view. 1... Heat source, 2... Heat fixing roller, 3...
Support plate, 4, 24...Bearing, 12...Core metal, 12
a...One end of the core metal, 12b...The outer peripheral surface of the core metal, 1
2c, 12c'...non-circumferential portion, 22...elastic layer,
32...peripheral groove, 32a...bottom.

Claims (1)

[Scope of utility model registration request] In a heat fixing device equipped with a heat fixing roller rotatably supported by a bearing, at least one circumference is provided on at least one of the outer circumferential surface of the core metal of the heat fixing roller and the inner circumferential surface of the bearing that fit together. A groove is formed, and the non-circumferential groove portions of both are brought into contact with each other and fitted, and the circumferential groove and the circumferential groove and/or the circumferential groove and the non-circumferential groove of both are fitted in a non-contact manner. Characteristic heat fixing device.