JPH103223A - Thermal roller fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reuse the core bar of a heating roller which is a periodically exchanged part. SOLUTION: A mechanism inhibiting slip in a rotating direction with respect to the boss part 10b of a heat insulating member 12 is provided at the heating roller 1 that incorporates a heater H and where the surface of a roller part 10a is coated with releasing agent 11 and bearings 13 are provided at the boss parts 10b of roller both ends through the heat insulating member 12. As the mechanism inhibiting the slip, means such as providing a plane part at the peripheral surface of the boss part 10b, providing a groove part in parallel with a shaft direction and providing an engaging part at the inner surface of the heat insulating member 12 are taken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat roller fixing device used in a copying machine or a printer for recording an image by an electrophotographic method.

[0002]

2. Description of the Related Art In an image forming apparatus for performing image recording by an electrophotographic system, an electrostatic latent image is formed on a photoreceptor, and the latent image is developed into a toner image. By transferring the recording paper on which the toner image has been transferred onto the recording paper and passing through the fixing device, the toner is fused and fixed on the recording paper.

As this fixing device, a heat roller fixing device is often used because it enables high-speed processing. The heat roller fixing device has a built-in heater and performs fixing by passing a recording paper with a toner image adhered between a heating roller that is driven and rotated and a pressure roller that presses the heating roller. The heating roller is made of a metal material such as an iron material, and has a cylindrical roller portion and boss portions provided on both sides of the roller portion to form a core metal portion and is hollow. A heater such as a rod-shaped infrared lamp is provided on the inner side, and the surface of the roller is controlled to be heated to around 200 ° C. during fixing.
In order to prevent the toner on the recording paper from adhering to the roller during fixing, a heat-resistant release material such as a fluororesin is applied to the roller surface. At both ends of the roller portion, boss portions having an outer diameter smaller than that of the roller portion are provided.
A bearing member for rotatably supporting the heating roller is provided at the boss portion, and is mounted on a frame of an external fixing device via the bearing member. Rotate through.

It is necessary to maintain the heating roller at a high temperature at the time of fixing, and it is not desirable that heat is released from the heated heating roller to the frame through the bearing member by heat conduction. Also, the performance of the bearing member itself deteriorates at high temperatures. As a method for coping with such a problem, a heat insulating member is provided between the boss portion and the bearing member to prevent the heat of the boss portion from being transmitted to the bearing portion.

Since the temperature difference between the room temperature and the heating temperature is large and the thermal expansion coefficients of the boss portion and the heat insulating member are also different, the heat insulating member is made of a resin material having heat resistance and low heat conductivity.
For example, PPS resin or the like is used, and is used as a sleeve having a split as shown in FIG. 6 and inserted into a cylindrical boss portion.

[0006]

In such a configuration, the conduction of heat to the bearing member is prevented, and the function as the bearing is maintained for a long time. However, there is a circumferential slip between the boss and the heat insulating member,
Streaks and wear occur on the circumference of the boss.

When the heating roller is used for a long time, the release material applied to the roller surface wears, causing toner adhesion and the like, resulting in deterioration of performance. Therefore, the heating roller is replaced as a regular replacement part when a predetermined number of sheets are fixed. For effective use of resources, the replaced heating roller is being studied for reuse by re-applying a release material to a cored bar. However, if the core metal whose boss portion is worn is reused as a heating roller, abrasion between the heat insulating member and the boss portion is further promoted, abnormal noise is generated, and the heat insulating member is further damaged. Therefore, the core metal of the heating roller could not be reused.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat roller fixing device having a heat roller capable of reusing such conventional problems.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heating roller having a built-in heater, applying a release material to the roller surface, and providing bearing members at boss portions at both ends of the roller via heat insulating members. The present invention is achieved by a heat roller fixing device including a pressing roller that presses, wherein a non-slip mechanism that inhibits the heat insulating member from sliding in the rotational direction with respect to the boss portion is provided.

[0010] The anti-slip mechanism for inhibiting the sliding of the heat insulating member in the rotation direction with respect to the boss portion includes an engaging portion which engages between the boss portion and the heat insulating member in a plane parallel to the rotation axis. In a preferred embodiment, the heat insulating member has a structure capable of being detached from an end of the boss portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a cross-sectional shape of a fixing section of a heat roller fixing device, wherein 1 is a heating roller, 2 is a pressure roller, and a heating roller which has a heater H inside and rotates. The pressure roller 2 is in a pressed state with respect to the first roller portion 1a, and the fixing is performed while the recording paper P on which the toner image is adhered is nipped and conveyed.

In the roller portion of the heating roller 1, a heat-resistant release material 11 is applied to a uniform thickness on the outer periphery of the cylindrical cored roller portion 10a.

FIG. 2 shows the axial cross section of the heating roller 1. A boss 10b having an outer diameter smaller than that of the roller is provided at both ends of the roller 10a. Core 1
The bearing 13 is attached to the 0 boss 10b via a heat insulating member 12, and the outer periphery of the bearing 13 is fixed to the frame 3. The gear 14 is attached to one boss 10b by a fixing means provided on the boss 10b. At the ends of the bosses 10b on both sides, a narrow groove portion 10c is provided on the circumference.
The gear 14 is prevented from coming off the shaft end of the boss 10b.

Heat roller 1 of the heat roller fixing device of the present invention
Then, the heat insulating member 12 is attached to the boss 10 b of the cored bar 10.
Is provided with a non-slip mechanism for inhibiting slip between the cored bar 10 and the heat insulating member 12 so that no slip occurs in the rotation direction. FIGS. 3 shows an embodiment of the mechanism.

FIG. 3 shows the first embodiment, and FIG. 3 (a) shows a cross section taken along line AA in FIG. A flat cut portion 101 is provided on the boss portion 10b of the metal core 10, and the cut portion 10 is provided on the inner surface of the heat insulating member 12.
By inserting the heat insulating member 12 from the shaft end of the boss 10b, the sliding in the rotational direction between the boss 10b and the heat insulating member 12 is prevented. Prohibition. FIG. 3B is a perspective view of the boss of the present embodiment, and FIG. 3C is a perspective view of a heat insulating member.

FIG. 4 shows a second embodiment. FIG. 4A shows a cross section taken along the line AA in FIG. 2, and FIG.
4 is a perspective view of the boss portion, and FIG. 4C is a perspective view of the heat insulating member. In the present embodiment, the boss portion 10b is provided with an axial groove-like fitting portion 102 and the heat insulating member 12 is provided with an axially extending strip-shaped protrusion 122 on the inner surface thereof.
By inserting the heat insulating member 12 from the end of the shaft 0b, the protruding portion 122 and the fitting portion 102 are engaged with each other, and the sliding of the heat insulating member 12 in the rotation direction with respect to the boss 10b is prohibited.

Since the heat insulating members shown in FIGS. 3 (c) and 4 (c) are manufactured by molding, the heat insulating members having such shapes can be easily obtained. The heat insulating member 12 is easily inserted and removed from the end of the boss portion 10b, and by inserting the washer 15 into the groove portion 10c in the inserted state, the heat insulating member 12 does not come out of the heating roller 1 and is not rotated. It can be used without slippage.

The gear 14 is attached to one boss 10b, and the fitting portion of the gear 14 with the boss 10b is formed in the same shape as that of the first or second embodiment. The assembly of the heating roller 1 is completed by a very simple operation of inserting the heat insulating member 12 or the heat insulating member 12 and the gear 14 sequentially into the boss portion 10b and fitting the washer 15 into the groove portion 10c.

FIG. 5 shows a third embodiment, and FIG. 5 shows a cross section taken along line AA in FIG. In this embodiment, one or a plurality of small screw holes 123 are provided in the heat insulating member 12 toward the axis, and the boss portion 10 having a cylindrical outer periphery is provided.
By inserting the heat insulating member 12 into the hole b and screwing the set screw 103 into place, circumferential slippage between the heat insulating member 12 and the boss portion 12b is prevented. In this embodiment, since the set screw 103 tightened due to thermal expansion during use is loosened, it is necessary to use a heat-resistant adhesive or the like to prevent loosening. In this embodiment, the retaining washer 15 shown in FIG. 2 can be omitted.

[0020]

According to the present invention (claims 1 and 2),
It is possible to reuse the core metal of the replaced heating roller, and the heating roller replaced as a regular replacement part is used as good as new by re-applying the release material to the roller surface Resources can be reused as well as down.

According to the second aspect, in addition to the above effects, the assembling work is easy, and the assembling work can be completed in an extremely short time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a heat roller fixing device.

FIG. 2 is a sectional view of a heating roller.

FIG. 3 is a cross-sectional view of the first embodiment, a perspective view of a boss and a heat insulating member.

FIG. 4 is a cross-sectional view of the second embodiment, a perspective view of a boss and a heat insulating member.

FIG. 5 is a cross-sectional view of Embodiment 3.

FIG. 6 is a perspective view of a conventional heat insulating member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating roller 2 Pressure roller 10 Core metal 10a Roller part (core metal) 10b Boss part (core metal) 10c Groove part (core metal) 11 Release material 12 Heat insulation member 13 Bearing 14 Gear 15 Washer 101 Cut part 102 Fitting part 103 Small set screw 121, 122 Projecting part 123 Small screw hole

Claims (2)

[Claims] 1. A heat roller comprising a heating roller having a built-in heater, a release material applied to the roller surface, and bearing members provided on boss portions at both ends of the roller via heat insulating members, and a pressure roller pressing against the heating roller. The heat roller fixing device according to claim 1, further comprising a non-slip mechanism for preventing the heat insulating member from sliding in the rotation direction with respect to the boss portion. 2. The non-slip mechanism has an engaging portion between the boss portion and the heat insulating member that engages with each other on a plane parallel to a rotation axis, wherein the heat insulating member is an end of the boss portion. 2. The heat roller fixing device according to claim 1, wherein the heat roller fixing device is detachable from the unit.