JP2000321909A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of absorbing torsional stress applied on a halogen lamp without acting repeated stressing to the halogen lamp and capable of being fitted in a small space. SOLUTION: An almost cylindrical housing hole 38 is formed in a main body frame 19 to which a base member 31 is attached. Then, a semi-columnar holder 40 can be housed in the hole 38. The holder 40 can be moved in the axial direction of the hole 38 and around the axis thereof. Then, the halogen lamp 16 is fixed to the holder 40. Because of that, even when the frame 19 is thermally expanded, the holder 40 is not moved together with the frame 19 because it is not fixed to the frame 19. Therefore, that tensile stress acts on the lamp 16 fixed to the holder 40 because of the thermal expansion of the frame 19 is eliminated. Thus, the lamp 16 is not damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device mounted on an image forming apparatus such as an electronic copying machine or a printer.

[0002]

2. Description of the Related Art Laser printers, copiers and the like are provided with a fixing device for fixing toner on recording paper. As shown in FIGS. 8 and 9, the fixing device includes a heating roller 100 that melts a toner image on a storage medium at a predetermined fixing temperature, and a recording medium sandwiched and pressed between the heating roller 100 and a toner image. And a pressure roller 102 for fixing the toner onto the sheet onto which the image has been transferred (Japanese Patent Laid-Open No. 3-27074).

[0003] At the axis of the heating roller 100, a halogen lamp 104 formed of a glass tube is incorporated.
The outer peripheral surface of the heating roller 100 is raised to a predetermined temperature. The halogen lamp 104 usually has about 170 to 18
Heats up to 0 degrees.

On the other hand, a support hole 106A is formed in a holder 106 fixed to a resin frame 105, and the halogen lamp 104 is movably supported in the support hole 106A. Further, a leaf spring 112 is fixed to the holder 106, and the leaf spring 112 urges the flange 104A of the halogen lamp 104 to restrict the movement of the halogen lamp 104.

[0005] For this reason, the holder 106 is
Even if the support hole 106A moves in the axial direction of the halogen lamp 104 even if the support hole 106A moves in the axial direction of the halogen lamp 104 due to the thermal expansion of No. 5, no thermal stress acts on the halogen lamp 104.

However, depending on the amount of movement of the holder 106, the leaf spring 112 is
Since the biasing force for biasing the spring 04A differs, the halogen lamp 104 has a leaf spring 11 due to thermal expansion and contraction.
2 causes a repeated load to act, and the halogen lamp 104 is liable to fatigue fracture.

A harness 114 is attached to the tip of the halogen lamp 104, and the harness 114 is fixed to the holder 106 via a conductive plate 108. At this time, depending on the orientation of the harness 114,
In some cases, torsion stress acts on the halogen lamp 104 and the halogen lamp 104 is damaged.

Further, when the harness 114 is fixed to the holder 106 via the conductive plate 108, the harness 114 is made longer in advance in order to prevent disconnection of the harness 114 due to torsion and disconnection due to thermal expansion of the frame 105. It is necessary to secure a space for routing.

[0009]

SUMMARY OF THE INVENTION In view of the above, the present invention provides a fixing device capable of absorbing a torsional stress applied to a halogen lamp without applying a repetitive stress to the halogen lamp and mounting in a small space. The task is to

[0010]

According to the first aspect of the present invention, a fixing device is mounted in the image forming apparatus. The fixing device fixes the toner image on the recording medium by pressing and heating the recording medium on which the toner image is formed.

A heating roller and a pressure roller are disposed in a main body frame fixed to the image forming apparatus. The heating roller melts a toner image on a storage medium at a predetermined fixing temperature, and pressurizes the toner image. The roller nips and presses the recording medium with the heating roller.

A heating means is incorporated in the heating roller, and an end of the heating means is fixed to a support member. This support member is engaged with the main body frame, and is movable in the length direction of the heating means.

Therefore, even if the main body frame thermally expands,
The support member does not move with the movement of the main body frame. Therefore, no tensile stress acts on the heating means fixed to the support member, and there is no problem such as breakage of the heating means.

According to the second aspect of the present invention, the supporting member is a holder having an externally arcuate surface. On the other hand, a storage hole is formed in the main body frame, and holds the holder rotatably around the axis of the heating means.

Therefore, when the heating means is fixed to the holder, even if the heating means is fixed in a slightly displaced state, the holder is engaged with the storage hole so as to be rotatable around the axis of the heating means. The displacement between the heating means and the holder can be absorbed by rotating the holder about the axis, and no torsional stress acts on the heating means.

According to the third aspect of the present invention, the projecting portion projects from the holder. On the other hand, a groove is formed in the storage hole, and the groove engages with the protruding portion to allow the holder to move in the length direction and around the axis of the heating means.

For this reason, the holder is prevented from falling off, and since only the protrusion and the groove are engaged, the structure is simple, the workability of assembly is good, and no cost is required.

According to the fourth aspect of the present invention, the support members are provided at both ends of the heating means. For this reason, the position of the heating means in the heating roller in the axial direction can be adjusted, and an appropriate light distribution position can be obtained.

According to the fifth aspect of the present invention, the support member and the heating means are engaged with the main body frame so as to be able to be pulled out in the longitudinal direction of the heating roller.

Therefore, the heating means can be removed from the heating roller together with the supporting member only by removing the supporting member from the storage hole, and the replacement of the heating means is easy. Further, the time required for replacement can be reduced.

According to the sixth aspect of the present invention, the support member is formed of the same material as the main body frame.

For example, when the coefficient of linear expansion of the support member is larger than the coefficient of linear expansion of the main body frame, the protrusion may expand from the groove and move with the groove.
It is preferable that the support member and the main body frame are made of the same material, and the support member and the main body frame have the same linear expansion coefficient.

According to the seventh aspect of the present invention, the power transmitting means for transmitting power to the heating means together with the end of the heating means is fixed to the support member.

For this reason, even when the harness is fixed as the power transmission means, there is no problem of disconnection, and since the fixed portion does not move due to thermal expansion of the support member, it is assumed that a tensile stress acts on the harness. There is no need to set the harness long beforehand. Therefore, the harness can be made shorter than before, and there is no need to route it. Further, since it is not necessary to use a halogen lamp having an integrated harness, costs can be reduced.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, a fixing device 10 according to the present embodiment includes a heating roller 12 for melting a toner image on a storage medium at a predetermined fixing temperature, and a heating roller for heating the recording medium. And a pressure roller 14 for fixing the toner to the paper on which the toner image has been transferred by sandwiching and pressing between the pressure roller and the paper.

The heating roller 12 is formed of an iron-based thin steel tube, and its surface is coated with PFA having good releasability. A halogen lamp 16 of a glass cylinder is built in the shaft core. The halogen lamp 16 is mounted on resin body frames 18 and 19, which will be described later, and is controlled by a thermistor and a control device (not shown) so that the surface temperature of the heating roller 12 becomes constant.

The heating roller 12 has a bearing 20.
Is rotatably supported by the frame 21 via the. A gear (not shown) is attached to an end of the heating roller 12, and a rotational driving force is constantly applied by a gear (not shown) on the image forming apparatus side.

On the other hand, the pressure roller 14 for nipping and conveying the sheet between the heating roller 12 and the heating roller 12 is formed of an iron tube, and a heat-resistant silicon sponge layer is formed on the outer peripheral surface of the iron tube. This silicon sponge layer is tubing with a PFA film.

The pressure roller 14 is supported by a bearing 22.
4 urges the heating roller 12 toward the heating roller 12. As a result, the pressure roller 14 is pressed against the heating roller 12 to generate a predetermined nip force.

On the other hand, rectangular sealing portions 26 are provided at both ends of the halogen lamp 16, and bar-shaped terminals 28 project from the sealing portions 26 along the central axis of the halogen lamp 16.

To the terminal 28, conductive base members 30, 31 in the form of a rectangular flat plate are fixed by welding or the like. Holes 30A, 31A are formed in the base members 30, 31, and fixing screws 32 are provided. It can be inserted.

As shown in FIG. 6, a mounting portion 34 to which the base member 30 can be mounted is formed in the main body frame 18 to which the base member 30 is mounted, and a thread groove 34A is formed in the mounting portion 34. The fixing screw 32 is
Can be screwed in.

Thus, the base member 30 is attached to the mounting portion 3
4 and is fixed to the main body frame 18 with fixing screws 32 together with a harness 42 connected to a power supply.

On the other hand, as shown in FIG.
A substantially cylindrical storage hole 38 is formed in the main body frame 19 on which is mounted, and a rectangular groove 38 </ b> A is formed at the edge of the storage hole 38. In this storage hole 38,
A semi-cylindrical holder 40 can be stored. The holder 40 has a protrusion 40A protruding from an arc surface, and the protrusion 40A engages with the groove 38A.

Thus, the holder 40 is positioned in the storage hole 38 so as not to fall off. The length L1 of the groove 38A is longer than the length L2 of the protrusion 40A, and the width D1 of the groove 38A is larger than the width D2 of the protrusion 40A. For this reason, the protrusion 40A
Is movable in the axial direction and around the axis of the storage hole 38 in the groove 38A.

At the center of the holder 40, a screw groove 4 is provided.
0B is formed, and the fixing screw 32 can be screwed. For this reason, the base member 31 of the halogen lamp 16 can be fixed to the holder 40 with the fixing screw 32 together with the harness 42 connected to the power supply.

On the left and right under the holder 40, arms 44 and 46 extend along the arc surface of the holder 40. The bases of the arms 44 and 46 are
When the base member 31 is mounted on the mounting surface 40C of
An end face of the base member 31 is supported and the base member 31 is supported.
Is positioned.

A disc-shaped stopper 48 is formed on the arm 46 along an arc surface, and the distal end surface of the base member 31 contacts the stopper 48 to perform positioning in the length direction of the base member 31. At the same time, when the holder 40 is stored in the storage hole 38, the stopper 48 is flush with the main body frame 19.

Above the arms 44 and 46, the holder 4
The holding portion 50 extends along the 0 arc surface, and the base of the holding portion 50 holds the base member 31 together with the arms 44 and 46. The base of the arms 44 and 46 has a step 5
2 are formed, and the frontage is widened in order to easily fix the base member 31 to the mounting surface 40C.

Further, a holder wiring path 54 is provided between the arms 44 and 46 so that the harness 42 can be stored. On the other hand, a part of the peripheral wall of the storage hole 38 is cut out in the circumferential direction to form a rectangular main body wiring path 56. The harness 42 reaches the holder wiring path 54 through the main body wiring path 56.

With this configuration, after the harness 42 is fixed with the fixing screw 32, the harness 42 is connected to the holder wiring path 54.
Further, since the harness 42 can be accommodated in the main body wiring path 56 and does not interfere with the harness 42 and is not fixed in a bent state, there is no problem of disconnection. Further, both sides of the main body wiring path 56 are receiving portions 38B that rotatably support the arms 44 and 46.

The width of the main body wiring path 56 is the same as that of the harness 42.
, And even if the main body wiring path 56 moves in the axial direction of the halogen lamp 16 due to the thermal expansion of the main body frame 19, no tensile stress acts on the harness 42.

As described above, in this embodiment, as shown by the imaginary line in FIG. 3, even if the main body frame 19 moves due to thermal expansion, the holder 40 is not fixed to the main body frame 19, However, it does not move with the main body frame 19. Further, since a gap (represented by L2-L1) is provided between the groove 38A and the protrusion 40A, the groove 38A does not hit the protrusion 40A.

Therefore, no tensile stress acts on the halogen lamp 16 fixed to the holder 40 due to the thermal expansion of the main body frame 19, so that the halogen lamp 16 is not damaged.

Further, since the holder 40 does not move,
No tensile stress acts on the harness 42, and there is no problem of disconnection. The width of the main body wiring path 56 is the same as that of the harness 42.
, The tensile stress does not act on the harness 42 even when the main body wiring path 56 moves in the axial direction due to the thermal expansion of the main body frame 19.

For this reason, since it is not necessary to set the harness 42 in advance long assuming that a tensile stress acts on the harness 42, the harness 42 can be made shorter than before and the harness 114 needs to be routed. Cost can be reduced.

When the base members 30, 31 are fixed to the terminals 28 of the halogen lamp 16 during the manufacture of the halogen lamp 16, the surfaces of the base members 30, 31 are slightly displaced from the surface of the sealing portion 26. Even if they are fixed by a gap, as shown in FIG. 4, since a gap (represented by D2-D1) is provided between the protruding portion 40A and the groove portion 38A, the angle θ of the gap can be rotated. Become.

For this reason, after the halogen lamp 16 is fixed to the holder 40, the holder 40 can rotate along the arc surface in the storage hole 38, so that the sealing portion 26 and the base members 30, 31 The sticking displacement is absorbed, and no torsional stress acts on the halogen lamp 16.

Further, even if the main body frame 19 is twisted due to thermal expansion, the holder 40 is rotatable with respect to the storage hole 38, so that the holder 40 cannot be rotated with the torsion of the main body frame 18. No torsional stress or the like acts on the halogen lamp 16 (see FIG. 1) fixed to the holder 40.

When the linear expansion coefficient of the holder 40 is larger than the linear expansion coefficient of the main body frame 19, the protrusion 40
A expands from the groove 38A and the protrusion 40A becomes the groove 38A.
The holder 40 is formed of the same material as that of the main body frame 19 because it may move together with the main body frame 19.

Further, as a modification of this embodiment, FIG.
As shown in (1), a holder 60 that can move in the axial direction of the halogen lamp 16 may also be mounted on the body frame 18 side. In this case, the storage hole 62 of the main body frame 18
A long groove (not shown) is formed, and the holder 60 is screwed into the storage hole 62 through the long groove.

With such a structure, the holder 60 can be fixed after positioning the halogen lamp 16 in accordance with the light distribution position of the halogen lamp 16.

The holder 60 is not limited to the above specification.
It is only necessary that the holder 60 can be moved in the axial direction of the halogen lamp 16 in order to adjust the light distribution position of the halogen lamp 16 and that the holder 60 can be fixed after the adjustment.

Next, a method of mounting the halogen lamp 16 used in the fixing device according to this embodiment will be described.

As shown in FIG. 6, the halogen lamp 16 is inserted through the shaft of the heating roller 12, and the base member 30 is mounted on the mounting portion 34 of the main frame 18. Next, the fixing screw 32 is inserted into the terminal hole 42 </ b> B of the harness 42 and further inserted into the hole 30 </ b> A of the base member 30.

Next, the fixing screw 32 is screwed into the screw groove 34A of the mounting portion 34 from the opening 35 with a screwdriver, and the base member 30 and the harness 42 are fixed to the main body frame 18 as shown in FIG. At this time, the harness 42 is stored in the main body wiring path 36. Next, as shown in FIG. 1, the protrusion 40 </ b> A of the holder 40 is engaged with the groove 38 </ b> A of the storage hole 38, and the holder 40 is inserted into the storage hole 38 of the main body frame 19.
To store.

Then, with the terminal hole 42B of the harness 42 inserted through the fixing screw 32, the fixing screw 32 is inserted into the hole 31A of the base member 31. Next, the fixing screw 32 is screwed into the screw groove 4 of the holder 40 through the opening 41 with a screwdriver.
Then, the base member 31 is fixed to the holder 40. At this time, the harness 42 is stored in the holder wiring path 54 and the main body wiring path 56.

Next, a method of removing the halogen lamp 16 used in the fixing device according to this embodiment will be described.

First, the fixing screw 32 is removed from the openings 35 and 41 with a screwdriver, and the harness 42 is connected to the base member 3.
Remove from 0, 31. Next, as shown in FIG. 7, the holder 40 is pulled out in the direction of the arrow. The halogen lamp 16 is fixed to the holder 40, and the halogen lamp 16 is easily taken out of the heating roller 12 simply by pulling out the holder 40. Therefore, the halogen lamp 16
Replacement is easy, replacement time is reduced, and workability is good.

[0060]

According to the present invention, the support member does not move with the movement of the main frame even if the main frame is thermally expanded. Therefore, no tensile stress acts on the heating means fixed to the support member, and there is no problem such as breakage of the heating means.

When the heating means is fixed to the holder, even if the heating means is fixed in a slightly displaced state,
Since the holder is rotatably engaged with the storage hole around the axis of the heating means, the misalignment between the heating means and the holder can be absorbed by rotating the holder about the axis, and the torsion stress is applied to the heating means. Does not work.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a holder and a main body frame used in a fixing device according to an embodiment.

FIG. 2 is a vertical sectional view showing a fixing device according to the exemplary embodiment.

FIG. 3 is a horizontal sectional view showing a holder and a main body frame used in the fixing device according to the exemplary embodiment.

FIG. 4 is a side view showing a holder and a main body frame used in the fixing device according to the exemplary embodiment.

FIG. 5 is a vertical sectional view showing a modification of the fixing device according to the exemplary embodiment.

FIG. 6 is an exploded perspective view showing one end side of a halogen lamp used in the fixing device according to the exemplary embodiment.

FIG. 7 is a horizontal sectional view showing extraction of a halogen lamp used in the fixing device according to the exemplary embodiment.

FIG. 8 is a vertical sectional view showing a conventional fixing device.

FIG. 9 is an exploded perspective view showing a holder and a main body frame used in a conventional fixing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fixing apparatus 12 Heating roller 14 Pressure roller 16 Halogen lamp (heating means) 18 Main body frame 19 Main body frame 30 Base member (power transmission means) 31 Base member (power transmission means) 38 Storage hole 38A Groove part 40 Holder (supporting member) 40A Projection Part 42 Harness (power transmission means) 60 Holder (support member) 62 Storage hole

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hiroyuki Okawa 3-7-1, Fuuchi, Iwatsuki-shi, Saitama F-term in the Fuji Xerox Co., Ltd. Iwatsuki Office 2H033 AA21 AA23 BB21 BB22 3K058 AA95 BA18 CE12 CE17 DA02 GA06 3K092 PP18 QA02 QB24 RA03 TT09 VV40

Claims (7)

[Claims] 1. A fixing device for fixing a toner image on a recording medium, which is loaded in the image forming apparatus and on which a toner image is formed, by pressing and heating the recording medium, wherein the main body is fixed to the image forming apparatus. A frame, a heating roller disposed in the main body frame for melting the toner image on the storage medium at a predetermined fixing temperature, and a heating roller disposed in the main body frame to transfer the recording medium to the heating roller. A pressure roller for holding and pressing, a heating means built in the heating roller, and a support member fixed to an end of the heating means and engaged with the main body frame so as to be movable in the longitudinal direction of the heating means. A fixing device characterized by the above-mentioned. 2. The method according to claim 1, wherein the support member is a holder having an externally arcuate surface, and a storage hole is formed in the main body frame to hold the holder rotatably around the axis of the heating means. The fixing device according to claim 1. 3. A protruding portion protruding from the holder, and a groove formed in the storage hole and engaged with the protruding portion to allow the holder to move in the longitudinal direction and around the axis of the heating means. The fixing device according to claim 2, further comprising: 4. The fixing device according to claim 1, wherein said support members are provided at both ends of said heating means. 5. The fixing device according to claim 1, wherein the support member and the heating unit are engaged with the main body frame so as to be able to be removed in a length direction of the heating roller. 6. The fixing device according to claim 1, wherein said support member is formed of a material of the same quality as said main body frame. 7. The fixing device according to claim 1, wherein a power transmission unit that transmits power to the heating unit is fixed to the support member together with an end of the heating unit.