KR100477662B1 - Fusing device of electrophotographic image forming apparatus - Google Patents

Abstract

A fixing apparatus of an electrophotographic image forming apparatus is disclosed. The fixing apparatus of the disclosed electrophotographic image forming apparatus includes an insulating cylindrical roller having a predetermined thickness, a resistance coil which generates heat by receiving electricity from the outside while wrapping the cylindrical roller in a spiral, and a rubber layer covering the resistance coil on the cylindrical roller. A fixing roller; And a pressure roller for bringing the paper passing between the fixing roller and the fixing roller into close contact with the fixing roller. According to this, the fixing roller of the electronic image forming apparatus according to the present invention has a simple structure and is easy to manufacture. In addition, since both ends are blocked, heat dissipation to both ends is suppressed, thereby increasing thermal efficiency and reducing power consumption.

Description

Fusing device of electrophotographic image forming apparatus

The present invention relates to a fixing apparatus of an electrophotographic image forming apparatus, and more particularly, to a fixing apparatus of an electrophotographic image forming apparatus having an insulating cylindrical roller and having a fixing roller having a simple structure.

The electrophotographic image forming apparatus includes a fixing device that heats a sheet on which a toner image is transferred, temporarily melts a toner image in a powder state on the sheet, and fuses the sheet to the sheet. The fixing apparatus includes a fixing roller for fusing toner to paper, and a pressure roller for pushing the paper toward the fixing roller.

1 is a schematic cross-sectional view of a conventional fixing roller in which a halogen lamp is applied as a heat source, and FIG. 2 is a schematic longitudinal cross-sectional view of a fixing apparatus employing the fixing roller of FIG. 1.

Referring to FIG. 1, the fixing roller 10 includes a cylindrical roller 11 and a halogen lamp 12 installed at an inner center thereof. Teflon coating layer (11a) is formed on the surface of the cylindrical roller (11). The halogen lamp 12 generates heat in the cylindrical roller 11, and the cylindrical roller 11 is heated by the radiant heat from the halogen lamp 12.

Referring to FIG. 2, the pressure roller 13 is positioned below the fixing roller 10 so as to face the fixing roller 10 with the paper 14 therebetween. The pressing roller 13 is elastically supported by the spring 13a to closely adhere the paper 14 passing between the fixing roller 10 and the pressing roller 13 to the fixing roller 10 at a predetermined pressure. At this time, the paper 14 on which the powder toner image 14a is formed is fused to the paper 14 by a predetermined pressure and heat while passing between the fixing roller 10 and the pressure roller 13.

One side of the fixing roller 10 has a thermistor 15 for measuring the surface temperature of the fixing roller 10 and a power supply to the halogen lamp 12 when the surface temperature of the fixing roller 10 exceeds a set value. Thermostat (16) is installed to block the. The thermistor 15 measures the surface temperature of the fixing roller 10 and transmits the electric signal measured by the controller (not shown) of the printer (not shown), and the controller supplies the halogen lamp 12 according to the measurement temperature. The power is controlled to maintain the surface temperature of the fixing roller 11 within a given range. In addition, the thermostat 16 is the contact of the thermostat 16 when the temperature of the fixing roller 10 by the thermistor 15 and the control unit fails to adjust because the temperature of the fixing roller 10 is higher than the threshold set value ( Open the power (not shown) to cut off the power flowing to the halogem lamp 12.

In the conventional fixing device using the halogen lamp 12 as a heat source, both ends of the fixing roller are open so that some heat is released to the outside, and the fixing roller is heated by radiant heat from the heat source. It is difficult to maintain a constant temperature of the fixing roller because the compensation of the temperature deviation caused by the temperature drop generated while contacting is slow.

Therefore, a new heat source is required to block both ends of the fixing roller, and accordingly, a fixing device having a new structure for supplying power to the heat source is required.

The present invention has been made to improve the above problems, and an object of the present invention is to provide a fixing apparatus of an electrophotographic image forming apparatus having both ends closed and having a simple structure.

In order to achieve the above object, the fixing apparatus of the electrophotographic image forming apparatus includes an insulating cylindrical roller having a predetermined thickness, a resistance coil which generates heat by receiving electricity from the outside while wrapping the cylindrical roller in a spiral, and the cylindrical roller. A fixing roller having a rubber layer covering the resistance coil thereon; And

And a press roller for bringing the paper passing between the fixing roller and the fixing roller into close contact with the fixing roller.

The cylindrical roller is made of a heat-resistant plastic, it is preferable that the glass fiber is reinforced by one of the plastic selected from the group consisting of polyphenylene sulfide (PPS), poly butylene terephthalate (PBT), poly thylen terephthalate (PET).

Moreover, it is preferable that the said cylindrical roller is 1-3 mm thick.

On the other hand, the rubber layer is preferably made of a silicon material of 1 to 3 mm thick.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thicknesses of layers or regions illustrated in the drawings are exaggerated for clarity.

3 is a schematic cross-sectional view of a fixing device of an electrophotographic image forming apparatus according to a preferred embodiment of the present invention, and FIG. 4 is a sectional view taken along line IV-IV of FIG.

3 and 4, the fixing device 100 includes a fixing roller 110 including a cylindrical roller 114 rotating in a direction in which the paper 150 on which the toner image 151 is formed (the arrow A direction) is discharged. And a pressing roller 160 which is installed to face the fixing roller 110 with the paper 150 therebetween and rotates in the direction of arrow B while pressing the paper 150 to the fixing roller 110.

The surface of the cylindrical roller 114 is provided with a silicone rubber layer 112 of a predetermined thickness, for example, 1 to 3 mm, and a toner release layer 111 of teflon material having a thickness of 20 to 30 μm on the silicone rubber layer 112. Is formed. Between the cylindrical roller 114 and the rubber layer 112, a resistance coil 113 is wound in a spiral.

On the other hand, a thermistor 118 for measuring the surface temperature of the fixing roller 110 is provided above the toner release layer 111. In addition, when the surface temperature of the fixing roller 110 rises sharply, a thermostat 119 is installed to cut off the power supplied to the resistance coil 113 to prevent overheating.

The resistance coil 113 uses a Ni-Cr wire or a Cr-Fe wire that generates heat by electricity supplied from the outside. Both ends of the resistance coil 113 are provided with lead wires 117 for connecting external electricity.

The cylindrical roller 114 is made of an insulating material to be in contact with the resistance coil 113 and to prevent a short circuit of electricity. In addition, in order to maintain the surface operating temperature of the fixing roller 110 of about 175 ℃, the portion that is in contact with the resistance coil 113 is a heat-resistant material that can withstand at 220 ~ 230 ℃. For example, it may be made into a mold using resins such as PPS (Polyphenylene sulfide), PBT (Poly Butylene Terephthalate), PET (Poly Ethylen Terephthalate) containing fillers such as glass fiber having low thermal deformation even at high temperatures. .

In addition, the surface of the rubber layer 112 which is in direct contact with the paper 150 to which the toner image has been transferred through the toner release layer 111 should be maintained at about 175 ° C., but the inner surface which is in contact with the resistance coil 113 is maximum It should be able to be used at 230 ~ 240 ℃. Therefore, a silicon material that withstands high temperatures is used. The rubber layer 112 forms a fixing nip having a predetermined width, for example, 6 to 7 mm, to help fixation of the paper 150 passing through the pressing roller 160.

At both ends of the fixing roller 110, the first 120 and the second end cap 130 are fitted to both ends of the cylindrical roller 114 on the rotation axis of the fixing roller 110. Most of the second end cap 130 is the same as the first end cap 120 in the structure, except that the gear 131 is formed along the outer circumferential surface of the second end cap 130 to form a gear ( (Not shown) is rotated in conjunction with. On both ends of the fixing roller 110, there are provided bearings 133 for supporting the rotating fixing roller.

5A and 5B are perspective views of the first end cap 120 of FIG. 3, and FIGS. 6A and 6B are perspective views of the second end cap 130 of FIG. 3.

5 to 6, lead wires 122 and 132 through which lead wires (reference numeral 117 of FIG. 3) connected to both ends of the resistance coil 113 pass through the first 120 and the second end caps 130. ) Are formed respectively. Electrode grooves 126 and 136 into which the electrode 210 is inserted are formed in the outer center portion of the end caps 120 and 130. The electrode 210 enters the lead wire holes 122 and 132 to supply electricity to the lead wire 117 that is bent at right angles.

7 is an exploded perspective view of the power connection part 200 connected to the second end cap 130. Referring to the figure, the power connection unit 200 is installed in the frame (see 170 of FIG. 3), receives an external power supply and transfers it to the resistance coil 113. The power connection part 200 includes an electrode 210 inserted into the electrode grooves 126 and 136, a brush 220 installed to contact the electrode 210, and the brush 220 is the electrode 210. It is provided with an elastic means 240 to be in close contact with the electrical connection.

The brush 220 is connected to a lead wire (see 254 of FIG. 3) from the outside to transfer electricity to the electrode 210.

The elastic means 240 provides an elastic force to the spacer 230 so that the brush 220 is in close contact with the electrode 210, the deformation even when the thermal expansion or thermal contraction occurs repeatedly during the operation of the fixing roller 112 Absorption of the brush 220 prevents the brush 220 from falling off from the electrode 210. Therefore, it is preferable that the elastic means 240 use a compression spring. At this time, a lead wire 254 of FIG. 3 is connected to the brush 220 through a lead wire hole 252 from the outside, and there is a risk that the lead wire 254 and the elastic means 240 are in contact with each other to generate sparks. . Therefore, a spacer 230 is installed to prevent such a risk and to prevent the brush 220 from being pushed back so that the end cap 230 touches the frame 170.

The elastic means 240 is fixed in the frame 170 by an insulating plate 250. The insulating plate 250 supports the elastic means 240. Therefore, the brush 220 is first installed in the through hole formed in the frame 170, and then the elastic means 240 and the spacer 230 are installed. Then, the insulating plate 250 is installed so that the elastic means 240 does not fall back.

The end caps 120 and 130 are molded using resins such as PPS (Polyphenylene sulfide), PBT (Poly Butylene Terephthalate), and nylon (Nylon), which are filled with fillers such as glass fiber (Glass Fiber), which has low thermal deformation even at high temperatures. Is produced by.

The pressure roller 160 has an elastic roller 161 for contacting the fixing roller 110 to form a fixing nip, and a shaft 162 for supporting the elastic roller 161 at the center of the elastic roller 161. Equipped. Bearings 163 are provided on outer peripheries of both ends of the shaft 162 to support the pressure roller 160. The pressure roller 160 is installed in close contact with the fixing roller 110 or provided with a separate spring (not shown) for pressing the shaft 162 toward the fixing roller 110 to rotate the fixing roller 110. Driven driven.

The operation of the fixing device of the electrophotographic image forming apparatus having the above structure will be described in detail with reference to the drawings.

When electricity supplied from the external lead wire 254 is connected to the lead wire 117 of the resistance coil 113 through the brush 220 and the electrode 210, the electricity generates heat in the resistance coil 113. The generated heat is transferred to the rubber layer 112 so that the surface temperature of the fixing roller 110 reaches the target temperature required for fusion of the powdered toner 151 formed on the paper 150 within a short time.

Subsequently, in the printing mode, the powdery toner 151 is transferred to the printing paper 150, and the paper 150 passes between the fixing device 110 and the pressure roller 160 installed opposite thereto. It is fused to the paper 150 by the fixing roller 110 having a constant temperature.

On the other hand, when the fixing roller 110 loses heat to the paper 150 as the toner 151 is fused to the paper 150, power is supplied to the resistance coil 113 to fix the fixing roller ( The surface temperature of 110 can be maintained at a target temperature suitable for fusion of the toner 151.

Then, the thermistor 118 measures the surface temperature of the fixing roller 110 to maintain the surface temperature within a predetermined range suitable for fusion of the toner 151. If the surface temperature control by the thermistor 118 fails and the surface temperature of the fixing roller 110 rises sharply, the thermostat 119 mechanically operates the power of the power connection unit 200 connected thereto. Blocking to prevent the sudden rise of the surface temperature of the fixing roller (110). The power supply operation can be varied according to the set temperature, and the power supply is also controlled by periodic on / off (0N / OFF) type, pulse width modulation, or PI (Proportional and Integral). It is possible to apply.

As described above, the fixing roller of the electronic image forming apparatus according to the present invention has a simple structure and is easy to manufacture. In addition, since both ends are blocked, heat dissipation to both ends is suppressed, thereby increasing thermal efficiency and reducing power consumption.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those of ordinary skill in the art that various modifications and variations can be made therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a schematic cross-sectional view of a conventional fixing roller in which a halogen lamp is applied as a heat source.

FIG. 2 is a schematic longitudinal sectional view of the fixing device including the fixing roller shown in FIG. 1.

3 is a schematic cross-sectional view of a fixing apparatus according to a first embodiment of the present invention.

4 is a cross-sectional view taken along line IV-IV of FIG. 3.

5A and 5B are perspective views of the first end cap of FIG. 3.

6A and 6B are perspective views of the second end cap of FIG. 3.

7 is an exploded perspective view of the power connection unit of FIG. 3.

<Description of the symbols for the main parts of the drawings>

100: fixing device 110: fixing roller

111: toner release layer 112: rubber layer

113: resistance coil 114: cylindrical roller

117: lead wire 118: thermistor

119: Thermostat 120: the first end cap

130: second end cap 160: pressure roller

Claims (6)

A fixing roller having an insulating cylindrical roller made of a heat resistant plastic having a predetermined thickness, a resistance coil which generates heat by receiving electricity from the outside while wrapping the cylindrical roller in a spiral, and a rubber layer covering the resistance coil on the cylindrical roller; And And a pressure roller for closely contacting the sheet passing through the fixing roller with the fixing roller. And the rubber layer is in contact with the paper. delete The method of claim 1, wherein the cylindrical roller, Fixing apparatus of an electrophotographic image forming apparatus, characterized in that the glass fiber is reinforced on one of the plastics selected from the group consisting of polyphenylene sulfide (PPS), poly butylene terephthalate (PBT), and poly ethylene terephthalate (PET). The method of claim 1, wherein the cylindrical roller, A fixing apparatus for an electrophotographic image forming apparatus, characterized in that 1 to 3 mm thick. The method of claim 1, wherein the rubber layer, A fixing device of an electrophotographic image forming apparatus, characterized in that it is made of a silicon material. The method of claim 1, wherein the rubber layer, A fixing apparatus for an electrophotographic image forming apparatus, characterized in that 1 to 3 mm thick.