JP3105332B2 - Thermal fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal fixing device for thermally fixing a toner image on a recording medium to which a toner image has been transferred.

2. Description of the Related Art In an electrophotographic apparatus or the like, simply transferring a toner image onto a recording medium causes the toner to move or fall on the recording medium just by touching something. It is necessary to fix on a recording medium.

[0003]

2. Description of the Related Art Generally, a heat fixing device of this type has a halogen lamp serving as a heat source arranged on a central shaft of a metal cylindrical heat roller, and heat roller is heated by heat radiated from the halogen lamp. doing.

FIG. 4 shows such a conventional heat fixing device, wherein 91 is a heat roller, 92 is a halogen lamp, and 93 is a pressure roller pressed against the heat roller 91 by a compression coil spring 94.

Reference numeral 95 denotes a cleaning felt for removing toner and the like adhering to the surface of the heat roller 91, and reference numeral 96 denotes an on / off control of the halogen lamp 92, which is performed by changing the surface temperature of the heat roller 91. A working thermostat.

[0006]

In the conventional heat fixing device constructed as described above, since most of the outer peripheral surface of the heat roller 91 is exposed to the air, the heat of the heated heat roller 91 is reduced. Escape from the outer surface into the air.

As a result, the halogen lamp 92 is further heated to compensate for the escaped heat, and there is a problem that a large portion of the power consumption originally consumes a larger amount of power and is inefficient.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat-fixing device which reduces heat dissipation from the outer surface of a heat roller, consumes less power, and is economical.

[0009]

In order to achieve the above object, a heat fixing apparatus according to the present invention comprises a recording medium between a pressure roller 11 and a pressure roller 11 as shown in FIG. A heat roller 13 that is rotationally driven across the heat roller 100; a heating element 18 for heating the heat roller 13; and an air layer between the heat roller 13 and the heat roller 13 to prevent heat from escaping from the outer surface to the air. And a heat-shielding cover 33 made of a heat-resistant and heat-resistant material that covers the exposed portion of the outer surface of the heat roller 13 so as to prevent the heat roller 13 from being exposed.

[0010]

The heat that escapes from the outer surface of the heat roller to the air is confined to the heat roller by the heat shield cover.

[0011]

An embodiment will be described with reference to the drawings. FIG.
1 shows an electrophotographic printer used for a printer, a copying machine, and the like. In FIG. 1, reference numeral 1 denotes a photosensitive drum which is driven to rotate at a constant speed.

Around the photosensitive drum 1, a charger 2 for uniformly charging the surface of the photosensitive drum 1 is used, and then image light is irradiated with a laser beam or a light emitting diode array.
An exposure device 3 for irradiating the surface of the photosensitive drum 1 is provided, whereby an electrostatic latent image is formed on the surface of the photosensitive drum 1.

Reference numeral 4 denotes a developing device for developing the electrostatic latent image formed on the surface of the photosensitive drum 1 into a toner image.
The toner image formed there is transferred to the recording paper 100 by the transfer device 5.

Reference numeral 6 denotes a static eliminator for neutralizing the surface of the photosensitive drum 1. Reference numeral 7 denotes a cleaner for cleaning the toner remaining on the surface of the photosensitive drum 1. 10 is a recording paper 100
Is a heat fixing device for fixing a toner image to the toner image.

FIGS. 1 and 3 show the heat fixing device 10. FIG. In the figure, reference numeral 11 denotes a pressure roller which is urged toward the heat roller 13 by the compression coil spring 9 and is rotatably supported by the bearing 12.

Heat roller 1 pressed against pressure roller 11
Reference numeral 3 denotes a cylindrical section made of an aluminum alloy or the like having a high thermal conductivity. The recording sheet 100 is sandwiched between the pressing roller 11 and the recording paper 100 and is rotated by a motor 14. 15 and 16 are gears for transmitting the driving force of the motor 14 to the heat roller 13. 17 is a heat roller 13
Bearing.

As the heating element 18 for heating the heat roller 13, an elongated halogen lamp is used, and the heat roller 13 is positioned at the center axis position of the heat roller 13.
Are arranged over the entire width of the object.

At a position substantially at the center in the width direction of the heat roller 13 and further in front of the pressure contact position of the two rollers 11 and 13 in the rotation direction of the heat roller 13, the operation is performed by receiving the surface temperature of the heat roller 13. The thermostat 20 is disposed to face the surface of the heat roller 13.

The control unit 23 controls the power supply 21 of the halogen lamp as the heating element 18 in accordance with the input signal from the thermostat 20. The control unit 23 also controls the rotation of the motor 14 and the like.

The upper half of the heat roller 13 is covered by a semi-cylindrical roller cover 30 over the entire width. The roller cover 30 is configured by sandwiching a heat shield cover 33 made of a heat-insulating and heat-resistant material between an inner cleaning felt 31 and an outer case 32 and fixing them to each other.

The ears 34 projecting upward from both side ends of the case 32 are inserted between slits 35 projecting inward from the apparatus frame, so that the case 32 does not rotate. I have.

The cleaning felt 31 is formed in such a shape as to be in close contact with the outer peripheral surface of the heat roller 13 so that an air layer is not formed between the cleaning felt 31 and the surface of the heat roller 13. Cleaning etc.

Asbestos is suitable as the material of the heat shield cover 33, but there is a possibility that a pollution problem may occur. For example, heat-resistant glass fiber or Pyromex aluminum processed product can be used instead.

In the heat fixing device of the embodiment having the above-described configuration, while the recording paper 100 passes between the heat roller 13 heated by the heating element 18 and the pressure roller 11 while being pressed against the toner, the toner The image is heat-fixed to recording paper 100.

Since the cleaning felt 31 is in close contact with the entire upper half of the outer surface of the heat roller 13, there is no direct escape of heat from the outer surface of the heat roller 13 to the air at that portion. Heat roller 13
Heat on the outer surface is conducted to the cleaning felt 31.

Then, the heat is prevented from being transmitted to the outside by the heat shield cover 33, and is confined inside the heat shield cover 33. Therefore, from the upper half of the outer surface of the heat roller 13, little heat escapes into the air and little heat conduction to the external member occurs.

The present invention is not limited to the above embodiment, but may be applied to an electrophotographic apparatus other than a printer, and it is also possible to thermally fix a toner image on a recording medium other than an electrophotographic apparatus. It can be applied to various necessary devices.

[0028]

According to the heat fixing device of the present invention, heat that escapes from the outer surface of the heat roller to the air can be confined to the heat roller side, and the heat that escapes to the air can be reduced. It has an excellent effect that it consumes less power and is very economical.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a heat fixing device according to an embodiment.

FIG. 2 is a configuration diagram of a printer according to an embodiment.

FIG. 3 is a front view of the heat fixing device of the embodiment.

FIG. 4 is a side sectional view of a conventional heat fixing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Press roller 13 Heat roller 18 Heating element 33 Heat shield cover 100 Recording paper

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-44966 (JP, A) JP-A 54-143242 (JP, U) JP-A 58-152650 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) G03G 15/20

Claims (1)

(57) [Claims] A heat roller rotatably driven with a recording medium interposed between the pressure roller, a heating element for heating the heat roller, and a cleaning device for cleaning toner adhered to an outer surface of the heat roller.
The heat roller is in close contact with the outer surface of
Creeper placed so as to cover the exposed surface of the roller
Cover the outer surface of the cleaning felt to prevent heat from escaping into the air from the outer surface of the heat roller .
And a heat shield cover made of a heat-insulating and heat-resistant material fixed to the outer surface of the cleaning felt .