JP2569481Y2 - Fixing device for image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fixing roller heated by a heater, and a pressure roller extending parallel to the fixing roller and in contact with the peripheral surface of the fixing roller. A fixing device that presses the pressure roller against the fixing roller to press the peripheral surfaces of both rollers against each other, and a supporting device that rotatably supports the fixing roller, wherein the fixing roller is heated by a heater. A fixing device of an image forming apparatus for fixing a toner image on a recording material by passing a recording material carrying a toner image between the rollers while rotating a pressure roller pressed against the roller. It is about.

[Conventional technology]

A fixing device of the above type used in an image forming apparatus such as an electronic copying machine, a printer or a facsimile has been conventionally known.

A journal at each end of a fixing roller in a conventional fixing device is rotatably supported via a bearing in a through hole formed in a base support plate of the support device. When the fixing roller is detached from the supporting device for the purpose of maintenance inspection of the fixing roller or replacement thereof, the bearing is first detached from the through hole, and then the fixing roller is pulled out from the through hole.

However, when the fixing roller is to be removed immediately after the operation of the fixing device is stopped, the fixing roller and its bearing are still heated to a high temperature, and the bearing is thermally expanded. And cannot be pulled out.

In the past, the fixing roller had to be detached after waiting for the bearing to cool down.However, since it usually takes a long time until the bearing cools down, the work efficiency has to be significantly reduced. Did not.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device of the type described at the beginning, which eliminates the above-mentioned conventional drawbacks and allows the fixing roller to be immediately detached even immediately after the operation of the fixing device is stopped.

[Means for solving the problem]

According to the present invention, in order to achieve the above object, in a fixing device of the type described at the beginning, the supporting device has a notch in which a bearing mounted on a journal portion at each longitudinal end of the fixing roller is fitted. A pair of base support plates, and a pair of pressing plates that fit into the respective notches and press each bearing of the fixing roller held in the corresponding notch, and each front notch detachably mounts each bearing of the fixing roller. In order to hold the fixing roller, a direction substantially perpendicular to the direction in which pressure is applied to the fixing roller from the pressing unit is formed in an approximately semicircular shape having an open portion, and the fixing roller and the fixing roller are aligned with respect to the central axis of the fixing roller. A pressing force receiving portion for receiving each bearing pressurized by the pressing means is provided at a portion of the pressing roller opposite to the pressing portion, and each of the pressing plates is bridged over the opening of each notch. And the above A base member that has a pressing portion that presses each bearing of the fixing roller from a direction substantially perpendicular to a direction in which pressure is applied to the fixing roller from the means, and that each bearing of the fixing roller can be attached to and detached from each notch. A fixing device characterized by being detachably fixed to the fixing device.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic view showing the internal structure of an electronic copying machine having a fixing device according to an embodiment of the present invention.

In FIG. 1, an ADF (automatic document feeder) mounted on an upper part of a copying machine main body 100 which is an example of an image forming apparatus main body.
A document such as a sheet document or a computer printout sheet is sent from the 101 toward the contact glass 102, and is returned to the ADF 101 via the contact glass portion or discharged to the trays 103 and 104.

The entire surface of the original sent on the contact glass 102 is instantaneously illuminated by the light source 105 via the mirror 106, and the reflected light image accompanying this illumination passes through the mirror 107, the lens 108, and the mirror 109, respectively. An image is projected on a belt photoconductor 111 which is an example of a latent image carrier.

The belt photoconductor 111 is driven to run in the direction of the arrow, and the surface thereof is uniformly charged in advance by the charging charger 112, after which the above-described image projection is performed. Thus, an electrostatic latent image is formed on the surface.

The electrostatic latent image is visualized as a toner image by a developing device 113, and the toner image is transferred by a transfer charger 110 to transfer paper sent from a paper feed unit 114 or a large capacity paper feed unit 314 through a pair of registration rollers 115. Transferred by corona discharge. After the transfer, the transfer paper passes through the fixing device 4 and is discharged to the tray 117 on the upper part of the copying machine main body 100. On the other hand, the surface of the photoconductor 111 is cleaned by the cleaning device 120 to remove residual toner and the like on the surface.

The transfer paper is an example of a recording material, and a recording material made of photosensitive paper may be used depending on the form of the copying machine.

Further, the illustrated copying machine is provided with a re-feeding device 7,
The transfer paper exiting the fixing device 4 is sent to the re-feeding device 7 by switching the switching claw 305, and the transfer paper is again fed from here to the photoconductor 111, and a toner image is formed on the back surface thereof. Is fixed by the fixing device 4 to obtain transfer paper on which images are formed on both sides.

Further, by switching the switching claw 306, the transfer paper can be transported to the sorter 3 via the reversing device 6 and sorted.

As shown in detail in FIG. 3, the fixing device 4 has a heater 2 penetrating therethrough and a fixing roller 12 to be heated by the heater 2 and a fixing roller 12 extending in parallel with the fixing roller 12 and A pressure roller 13 in contact with the peripheral surface of the pressure roller, a pressure unit described below, and a fixing roller support device 20 also described later.
0, and the pressing means presses the pressing roller 13 to the fixing roller 1
2 is pressed to bring the peripheral surfaces of both rollers 12, 13 into pressure contact with each other. Further, the support device rotatably supports the fixing roller 12. The fixing roller 12 heated by the heater 2 and the pressing roller 13 pressed against the roller 2 are in rolling contact with each other. By passing a recording material made of transfer paper P carrying a toner image through the nip portion 220 as shown by the arrow, the transfer paper surface on which the toner image is formed comes into contact with the fixing roller 12 and The toner image is fixed on the recording material made of the transfer paper P by the heat and pressure of the toner.

When replacing the fixing roller 12, the front cover 1 of the copying machine main body 100 is opened as shown by a chain line in FIG. 2, the fixing device 4 is pulled out as shown by an arrow A, and the fixing roller 12 is pulled out as described later. Take out upwards.

In the fixing device of this embodiment, as shown in FIGS. 4 and 5, a supporting device 200 for supporting the fixing roller 12 is divided into two units, a base unit 201 and a pressing unit 202. The base unit 201 includes a base support plate 26 located on the near side with respect to the front side of the copying machine main body.
And a base support plate 26a located on the back side thereof, and an oil pan 69, stays 67, 203, 2 for integrally connecting these support plates.
04 and 205 (FIG. 4 shows only a part of the stay 204). Thus, the oil pan 69 has both base support plates.
In addition to acting as a stay to fix 26, 26a together,
As described later, it also functions as a saucer for receiving oil. The oil pan 69 has a paper passage hole 307 (FIG. 4) through which the transfer paper P (FIG. 3) passes.

The pressing unit 202 also has a pressing plate 25 on the near side, a pressing plate 25a on the rear side, and stays 206 and 207 for integrally fixing and connecting these.The fixing roller 12 is also provided between these stays 206 and 207.
There is a slit 208 through which the transfer paper that passes between the pressure roller 13 and the pressure roller 13 passes.

In this specification, as is apparent from the above description, when similar members are provided on the near side and the far side, members located on the far side are denoted by reference numerals assigned to members on the near side. Are attached to each other to identify them, and members on the far side may not be shown.

As shown in FIG. 6, the journal portion 209 on the front side and the journal portion 209a on the rear side of the fixing roller 12 have bearings made of, for example, ball bearings via heat insulating bushes 29, 29a.
30,30a is assembled. In addition, as shown in FIGS. 4 and 5, cutouts 210 and 210a that are open are formed in both base support plates 26 and 26a of the base unit 201, and the above-described bearings 30 and 30a are respectively provided here. Mated. On the upper peripheral surface of each of the bearings 30 and 30a thus fitted,
As will be described in detail later, the holding portions 211 and 211a (FIG. 5) of the holding plates 25 and 25a in the holding unit 202 abut, and in this state, the holding plates 25 and 25a are connected to the base support plates 26 and 26a.
Assembled in That is, each holding plate 2 is provided with two positioning pins 27, 27a projecting from each base support plate 26, 26a.
The grooves 28, 28a formed in the 5, 25a are fitted respectively, and the holding plate 2
5,25a is positioned, and the holding plate 25,25a is
They are detachably fixed to the base support plates 26, 26a by the 12,212a. Bearings 30, 30a are each holding plate 25, 25a and each base support plate
The fixing roller 12 is rotatably supported by the fixing rollers 26 and 26a.

Also, one rail 215, 216 of a guide rail device 213, 214 shown in FIG. 3 and not shown in FIG. 4 is fixed to both base support plates 26, 26a of the base unit 201, and the other rails 217, 218 are copied. It is fixed to the machine frame of the machine body 100 (FIG. 2). In this way, the base unit
201 is supported by the copying machine main body 100.

The heat insulating bushes 29, 29a prevent the heat of the fixing roller 12 heated by the heater 2 from being transmitted directly to the bearings 30, 30a,
It functions to protect the bearings 30 and 30a.

As described above, the supporting device 200 of the present example includes the fixing roller 12
A pair of base support plates 26, 26a having cutouts 210, 210a into which the bearings 30, 30a attached to the journal portions 209, 209a at each longitudinal end of the base support plates 26, 26a, respectively.
Stays 67, 69, 203, 204, 205 that integrally connect the fixing rollers 6, 26a, and a pair of pressing plates 25, 2 that fit into the respective notches 210, 210a and press the respective bearings 30, 30a of the fixing roller 12 held by the notches 210, 210a.
5a and a stay 20 for integrally connecting these holding plates 25, 25a.
6,207, and a pair of pressing plates 25, 25a and stays 206, 207 connecting these pressing plates 25, 25a constitute an integral pressing unit 202, and a pair of base supporting plates 26, 25
Stay 67 connecting 26a and these base support plates 26, 26a
69, 203, 204 and 205 constitute an integrated base unit 201. The support device 200 is divided into a detachable base unit 201 and a holding unit 202, and the bearings 30, 30a are sandwiched and supported by these units 201, 202.

When removing the fixing roller 12, the fixing device 4 is first pulled out to the front side as described above.
1 moves toward the front side, that is, in the direction of arrow A (FIGS. 2 and 4) while being guided by the guide rail devices 213 and 214, and together with the pressing unit 202, the fixing roller 12 and the heater 2, And each element mentioned later moves to the front side integrally.

After pulling out the entire fixing device 4 as shown by the chain line in FIG. 2 in this way, the screws 212 and 212a are removed, the holding unit 202 is lifted upward, and detached from the base unit 201. As a result, the upper portion of the fixing roller 12 is opened, and the bearings 30 and 30a are supported by the notches 210 and 210a of the base unit 201, the upper portions of which are open.
If the 12 is lifted upward, the bearings 30, 30a are notched
210, 210a, and fix the fixing roller 12 to the base unit 201.
Can be removed from.

The new fixing roller can be supported on both units 201 and 202 in the reverse order to that described above, and then the whole is pushed into the back side opposite to the arrow A and the front cover 1 is closed to replace the fixing roller. To end.

The pressure roller 13 presses against the fixing roller 12 by the urging action of a pressure unit described in detail later. At this time, the fixing roller 12 is a pressure contact portion between the roller 12 and the pressure roller 13. At the nip portion 220, pressure is applied from the pressure roller 13 in the direction indicated by the arrow X in FIG. 5, and this force is received by the pressing force receiving portion Y of the support device 200 as described later. 4 and 5, each notch 210, 210a is provided with a corresponding one of the bearings 30, 30a of the fixing roller 12.
Is formed in a substantially semicircular shape in which a direction substantially perpendicular to the direction in which pressure is applied to the fixing roller from the pressing means is an open portion so that the fixing roller can be detachably held as described above. Each holding plate 25, 25a is bridged over the opening of each notch 210, 210a, and each bearing 30, 30a of the fixing roller 12.
Are detachably fixed to the respective base support plates 26, 26a as described above so that can be detached from the respective notches 210, 210a.

With such a configuration, usually, the fixing roller 12 is supported by being sandwiched between the respective base supporting plates 26, 26a and the respective pressing plates 25, 25a, and when the fixing roller 12 is removed, each of the pressing plates 25, 25a is connected to the respective base supporting plate.
It is only necessary to separate the bearings 30, 30a from the open portions of the cutouts 210, 210a by detaching them from the 26, 26a, and the work of removing the bearings 30, 30a can be performed very easily. Moreover, even immediately after the operation of the fixing device 4 is stopped, even if the fixing roller 12 and the bearings 30 and 30a are still heated to a high temperature and the bearings 30 and 30a are thermally expanded, the notches 210,
Since one side of 210a is an open portion, it is only necessary to remove these bearings 30, 30a from notches 210, 210a through the open portion, and the fixing roller can be easily separated.
Conventionally, since the bearing was fitted in a circular hole formed in the support plate, if the bearing was thermally expanded, it could not be removed, and had to wait until these cooled down, In the configuration of the fixing device, such a problem can be prevented, and the fixing roller 12 that is still hot can be immediately removed.

Also, each bearing 30, 30a of the fixing roller 12 is connected to each base support plate.
Since the fixing rollers 12 and 26 are held by the pressing plates 25 and 25a, the positioning accuracy of the fixing roller 12 is improved, and the fixing roller can be rotated in a stable state.

The fixing roller 1 shown in FIG.
2 is a drive gear fixed to the rear journal portion 209a, and the gear 219 is driven by a drive motor provided on the copying machine main body side when the fixing device 4 is pushed and set to the rear side as described above. When the fixing device 4 is operated, it is driven by this motor, and the fixing roller 12 rotates counterclockwise in FIG. In the illustrated example, the fixing roller 12
, A gear 219, the aforementioned heat-insulating bushes 29, 29a, and a bearing 30,
30a form a fixing roller unit in which all are integrally assembled, and as described above, the base unit 201 and the pressing unit 2
When the fixing roller 12 is attached to and detached from the 02, the entire fixing roller unit is integrally attached and detached.

By the way, as described above, the pressing force from the pressing unit acts on the supporting device 200 via the pressing roller 13 and the fixing roller 12, but the base supporting plate 26, which constitutes the supporting device 200, 26a is supported by the copying machine main body 100 and has high rigidity. On the other hand,
The reference numerals 25 and 25a are detachably supported by the base support plates 26 and 26a, and have relatively small rigidity. Therefore, when the pressure by the pressing means is applied to the supporting device 200 via the pressing roller 13 and the fixing roller 12, all the pressure is applied to each of the pressing plates 25 and 25a, and this receives the total pressure. , Screws 212, which fix the holding plates 25, 25a to the base support plates 26, 26a
When a large external force is applied to 212a, each holding plate 25, 25a is deformed, and in some cases, may be damaged. To prevent such a problem, the screws 212, 212a and the holding plate 25, 25a
Should be set high, but this way,
Its cost goes up. Also, if the holding plates 25, 25a are removed from the base support plates 26, 26a while the pressing plates 25, 25a are applied with a large pressing force from the pressing means, the Since the pressing force on the fixing roller 12 pressed by the pressing unit 202 with a large force is rapidly released, the fixing roller 12 is notched 210, 210a
There is also a risk of jumping out of

Therefore, the fixing device 4 of the present embodiment is configured such that the base units 201 are received by the respective base support plates 26, 26a of the respective bearings 30, 30a of the fixing roller 12 pressed by the pressing means. That is, as shown in FIG. 5, each notch 210, 210a is provided with a pressing means at a portion of the fixing roller 12 opposite to the pressure contact portion (nip portion 220) of the fixing roller 12 and the pressing roller 13 with respect to the center axis. Bearings 30 and 30a pressurized by
And a pressure receiving portion Y for receiving the pressure. Moreover, as described briefly above, each holding plate 25, 25a is configured to control the respective bearings 30, 30a of the fixing roller 12 from a direction substantially perpendicular to the direction in which pressure is applied to the fixing roller 12 from the pressing means. It has holding parts 211 and 211a for holding.

With this configuration, most of the pressure applied from the pressing unit via the pressing roller 13 is received by the two base support plates 26 and 26a of the support device 200, and the pressing plates 25 and 25a are applied to the pressing plates 25 and 25a by the pressing unit. Pressure has little effect. Therefore, there is no problem that the holding plates 25, 25a having relatively low rigidity are deformed or damaged. Further, since the base supporting plates 26 and 26a are supported by the copying machine main body 100 and originally have high rigidity, even if a large pressure is applied to the supporting plates 26 and 26a, the base supporting plates 26 and 26a are greatly deformed. Does not occur. Further, even if the pressing roller 13 is pressed against the fixing roller 12 by the pressing means,
Even if 5a is removed from each base support plate 26, 26a, since the pressure by the pressing means is hardly applied to the holding plate 25, 25a, the fixing roller 12 is notched 210, 210a.
No problem such as jumping out of the box occurs.

In addition, each holding plate 25, 25a functions to reinforce each base support plate 26, 26a that has been pressed by the pressing means. That is, assuming that the presser plates 25, 25a do not exist, when the base support plates 26, 26a receive the pressure from the pressing means from the direction of arrow X in FIG. , 26a, the base support plates 26, 26a may be slightly deformed in the direction in which the open portions of the cutouts 210, 210a expand. As mentioned above, the base support plate
26, 26a is a member whose rigidity is relatively large, but when notches 210, 210a are formed in such a member, a large pressure from the pressing means acts on the base support plates 26, 26a, The base support plates 26, 26a are slightly deformed as described above. When such deformation occurs, the position of the pressure contact portion between the fixing roller 12 and the pressure roller 13 is shifted, and there is a possibility that transfer paper cannot be conveyed correctly. However, as described above, each holding plate 25, 25a of this example is bridged over the opening of each notch 210, 210a and is fixed to each base support plate 26, 26a, so that each base support plate 26, 26a Even when the plates 26, 26a receive a large pressure by the pressing means, each of the base supporting plates 26, 2 is
6a can be prevented from being greatly deformed. Each notch 210,210a
The base support plates 26 and 26a can be prevented from being deformed so that the base is greatly expanded. Thereby, the fixing roller 12
The position of the pressure contact portion (nip portion 220) between the pressure roller 13 and the pressure roller 13 does not greatly shift, and the toner image can be fixed while always properly conveying the transfer paper. Base support plate
The 26, 26a and the holding plate 25, 25a cooperate with each other to effectively suppress their respective deformations.

Next, another configuration of the illustrated fixing device 4 will be described more specifically.

As shown in FIG. 3, the transfer paper P on which the toner image has been transferred from the photoconductor passes through the paper passage hole 307 (FIG. 4) of the oil pan 69, and is rotated counterclockwise in the fixing direction. roller
The transfer paper P is fixedly supported by the oil pan 69 between the pressure roller 12 and the pressure roller 13 that rotates in the clockwise direction in contact with the transfer roller 12, that is, the transfer paper P is sent to the nip portion 220 in contact with the pressure roller 13. Guided by left and right entrance guide plates 10, 11 (not shown in FIG. 4).

At this time, the tip of the right inlet guide plate 10 is formed into a mountain shape whose central portion C in the longitudinal direction protrudes in the direction approaching the fixing roller 12 as shown in FIG. As shown, when the peripheral surface of the fixing roller 12 is formed in a conical shape in which the diameter of the central portion in the longitudinal direction is reduced, the transfer paper P sent to the nip portion 220 while being guided by the entrance guide plate 10 is The transfer paper P is held in the nip 220 so as to be pulled toward the both side edges P2 because the transfer paper P comes into contact with the fixing roller 12 from the center P1.
This makes it difficult for the transfer paper P to have vertical wrinkles in the moving direction.

As described above, in order to prevent the generation of vertical wrinkles on the transfer sheet P, the leading end of the right entrance guide plate 10 is fixed to the fixing roller
It is desirable to dispose it near the peripheral surface of the twelfth part 12 and at a distance from the nip 220. On the other hand, when the transfer paper P has a large thickness, the leading end of the right-side entrance guide plate 10 should be separated from the peripheral surface of the fixing roller 12 and should not obstruct the transfer path. Nip 220
It is desirable to be located near. As described above, in order to prevent the generation of vertical wrinkles on the transfer paper P and to improve the transportability of the thick paper, mutually contradictory conditions are required for the leading end position of the right entrance guide plate 10.

In order to satisfy the above two requirements at the same time, the nip 22
It is advantageous to set the distance L1 to 0 to 18 to 32 mm and the distance L2 to the peripheral surface of the fixing roller 12 to 2 to 5 mm.

On the other hand, the transfer paper P is nipped at the entrance guide plate 11 on the left side.
When the transfer paper P is conveyed while being held by the paper 220, the rear end of the transfer paper P must be sufficiently separated from the tangent T of the surface of the fixing roller in the nip 220 as indicated by L3 so as not to contact the entrance guide plate 11. desirable. This is because the transfer paper P is held in the nip portion 220 and conveyed, and when the rear end of the transfer paper P hits the entrance guide plate 11, unfixed toner on the surface of the transfer paper P is removed by the entrance guide. Adheres to plate 11,
This is to prevent the heat from sticking to the guide plate 11 due to the heat and growing the large toner mass. If a large amount of toner is formed on the entrance guide plate 11, the leading end of the transfer sheet being conveyed is caught by the toner and causes a jam of the transfer sheet. For the same reason, it is advantageous that no sharp edge or irregularity is formed at the tip of the left entrance guide plate 11, and that it is formed flat as shown in FIG. This is because if there is such an edge or unevenness, the toner transferred from the transfer paper P tends to adhere thereto, and a toner lump is formed here.

The left entrance guide plate 11 serves to prevent the leading end of the transfer paper P from moving to the left side in FIG. 3 with respect to this guide plate, and to guide the transfer paper P to be fed into the nip portion 220. is there.

As described above, the heater 2 is inserted through the hollow portion of the fixing roller 12 to heat the fixing roller 12, and the heater 2 generates a large amount of heat at the center in the longitudinal direction and generates heat at both ends. The calorific value distribution is set so as to reduce the amount. If the amount of heat generated by the heater 2 is set to be equal over the entire length, when the transfer paper P having a narrow paper width is continuously passed, the fixing roller portion through which the transfer paper passes is taken up by the transfer paper. Although the temperature is maintained at an appropriate value, the temperature of the fixing roller end region is unnecessarily high because the region is not heated. At this time, the surface of the fixing roller 12 is coated with, for example, Teflon (trade name) as a release material for preventing toner from adhering. However, if the temperature of this surface is too high, the Teflon coat is broken. . In particular, in a high-speed copying machine, since a large-capacity heater 2 is used, the temperature at both end regions of the fixing roller tends to be high. For example, when a 2 kW heater 2 is used, the temperature at both end surfaces of the fixing roller is about 230 ° C. May be expensive.

In order to prevent such a problem, the amount of heat generated at both ends of the heater 2 is made smaller than the amount of heat generated at the center of the heater 2 as described above. In addition to adjusting the calorific value distribution of the heater 2 as described above, the calorific value distribution is made constant,
Although it is possible to make the thickness of both end regions of the fixing roller 12 thicker than the central portion so that the surface temperature at both ends of the fixing roller is lower than that at the central portion, the thickness of the fixing roller 12 can be reduced. If the thickness of the fixing roller is increased, the temperature rise time of the fixing roller at the start of use of the fixing device may increase. Therefore, in the illustrated configuration, the heat generation amount distribution of the heater 2 is adjusted as described above.

Each end of the heater 2 is supported by brackets 221 and 221a shown in FIG. 6, and these brackets are fixed to the base support plate 26 on the near side and the base support plate 26a on the back side of the base unit 201, respectively. (Figs. 4 and 5
In the figure, these brackets 221, 221a are omitted).

As shown in FIG. 3, the pressure roller 13 has a shaft 225, a core member 222 made of, for example, metal, which is rotatably supported via a bearing (not shown), and is laminated around the shaft 225. A low friction member having, for example, a Teflon tube having a surface roughness of about 1 μ outside the elastic body 223.
224 are stacked. By providing the low friction member 224 on the surface in this way, the outer peripheral surface of the pressure roller 13 can be smoothed, and the coefficient of friction with respect to the transfer paper P can be reduced.
The reason for such a configuration is as follows.

As described above, the fixing roller 12 is formed in a continuous shape. At that time, as shown in FIG.
When the difference between the minimum diameter D2 and the minimum diameter D2 is referred to as a continuous amount, generation of vertical wrinkles on the transfer paper P can be more effectively prevented as the continuous amount is increased.

On the other hand, the surface of the conventional pressure roller was not provided with a low friction member, and the elastic body was exposed on the surface, so that the surface roughness was about 8 μm. In the case where the surface of the pressure roller 13 is relatively rough as described above, if the squeeze amount is set to a large value in order to prevent the occurrence of vertical wrinkles of the transfer sheet as described above, Unlike vertical wrinkles,
A rib-like undulation extending in the lateral direction of the transfer paper P occurs.

For this reason, conventionally, the amount of squeezing has to be suppressed to about 0.06 to 0.1 mm to prevent the occurrence of rib-shaped undulations. It is not possible to enhance the effect of preventing the occurrence of blemishes.

Therefore, in the illustrated pressure roller 13, the low friction member 224 is provided on the surface thereof as described above to reduce the surface friction coefficient of the roller 13. With this configuration, the transfer paper P conveyed between the nip portions 220 is easily slipped with respect to the pressure roller 13, and the restraining force applied to the transfer paper P from the pressure roller 13 is reduced. Even if the continuation amount of 12 is set as large as about 0.1 to 0.25 mm, the transfer paper P
In this case, it is possible to prevent the inconvenience that rib-like waving occurs, and it is possible to obtain the effect of forming the fixing roller 12 in a conical shape without any support.

In addition, as the fixing roller 12, for example, a roller in which the outer peripheral surface of a core member made of a rigid body such as a metal is coated with Teflon as described above can be used.

Next, a pressing unit for pressing the pressing roller 13 against the fixing roller 12 and a configuration related thereto will be described.

As shown in FIG. 3, fulcrum pins 15 and 26 are provided on the inner surfaces of the base support plates 26 and 26a shown in FIGS. 4 and 5, that is, the surface facing the core member 222 of the pressure roller 13. 15a is protruded (rear side pins and members related thereto are not shown). Each of these fulcrum pins 15, 15a is provided with a pressing member 20, 20a.
And the fixing members 17, 17a are pivotally supported so as to be swingable in the direction of the arrow.

Screws 22 are provided on the inner surfaces of the base support plates 26 and 26a.
The blocks 16 and 16a are fixed to each other by 7,227a, and the upper ends of the fixing members 17 and 17a are screwed onto the blocks 16 and 16a.
3, 23a respectively.

Bearing parts 228, 228a are formed on each of the pressing members 20, 20a,
Here, the ends 21 and 21a of the pressure roller shaft 225 are respectively supported. Thus, the pressure roller 13 is supported by the pair of pressure members 20, 20a on the near side and the back side.

Adjustment screws 18, 18a are screwed to the fixing members 17, 17a, and spring receiving members 229, 229a, which are separate members from the fixing members 17, 17a, are attached to tips of the screws 18, 18a. . Pressing springs 19, 19a composed of compression coil springs are press-fitted between the respective spring receiving members 229, 229a and the respective pressing members 20, 20a, whereby the pressing members 20, 20a are connected to the fulcrum pins 15, 15a. Are urged in the counterclockwise direction in FIG. As a result, the shaft 225 of the pressure roller 13 is pressed,
Is pressed against the surface of the fixing roller 12.

To adjust the pressure contact force of the pressure roller 13 against the fixing roller 12, the adjusting screws 18 and 18a are rotated, and the spring receiving members 229 and 22 are rotated.
9a is moved to the left or right in FIG. 3 to adjust the force applied to the pressure springs 19, 19a. As a result, the spring force applied to the pressing members 20, 20a, that is, the spring force applied to the shaft 225 is adjusted, and the pressure contact force of the pressing roller 13 against the fixing roller 12 is adjusted. Thus, the nip portion 22
The width of 0 can be set to an appropriate size. After the adjustment, the nuts 22, 22a screwed to the adjustment screws 18, 18a are tightened to fix the adjustment screws 18, 18a to the fixing members 17, 17a.

When replacing the fixing roller 12 as described above,
It is necessary to release the pressure of the pressure roller 13 against the fixing roller 12. In such a case, before removing the fixing roller 12, the screws 23, 23a are removed from the blocks 16, 16a, and the fixing members 17, 17a are separated from the blocks 16, 16a. The fixing members 17, 17a, the pressing members 20, 20a supporting the pressing roller 13, and the support pins 15, 15a are rotated clockwise in FIG. Separated from roller 12.

Further, the distal ends of stopper screws 24, 24a are fixed to the respective pressing members 20, 20a, and these screws pass through the fixing members 17, 17a. When the pressing members 20, 20a and the fixing members 17, 17a are assembled as shown in FIG. 3, δ is provided between the heads of the stopper screws 24, 24a and the fixing members 17, 17a. The intervals indicated by are indicated.

As described above, when the screws 23, 23a are removed and the fixing members 17, 17a and the pressing members 20, 20a are rotated counterclockwise, the fixing members 17, 17a are pressed by the action of the pressing springs 19, 19a. The members 20, 20a move in the direction of expanding and expanding around the fulcrum pins 15, 1a, but when these members are opened by the above-mentioned δ, each of the fixing members 17, 1
7a hits the heads of the stopper screws 24, 24a, and further expansion is prevented. For this reason, the pressure springs 19 and 19a
Does not protrude from between the fixing members 17, 17a and the pressing members 20, 20a. If the stopper screws 24 and 24a are not provided,
When the 23, 23a is removed from the blocks 16, 16a, the fixing members 17, 1
7a and the pressure members 20, 20a open widely, and the pressure springs 19, 1
9a jumps out. Therefore, when the pressure roller 13 is again pressed against the fixing roller 72, the pressure springs 19, 19a are assembled between the fixing members 17, 17a and the pressure members 20, 20a, and then the screws are screwed.
23, 23a must be fastened to the blocks 16, 16a, and the assembling work becomes complicated. By providing the stopper screws 24, 24a, such a problem can be prevented.

By the way, the leading end of the transfer paper P passing through the nip 220 is
Depending on the paper quality, the form of the fixed toner image, etc., the paper is conveyed while adhering to the peripheral surface of the fixing roller 12 or the pressure roller 13 and then by the waist of the transfer paper itself or each roller 1.
Peeled from the peripheral surface of the roller 12 or 13 by the peeling claw 32, 40 pressed against the peripheral surface of 2, 13 and subsequently left and right exit guide plates
The sheet is discharged from the fixing device 4 while being guided by the pair of conveying rollers 34 and 35 while being guided by the rollers 33 and 42.

A plurality of, for example, ten peeling claws 32 on the fixing roller 12 side are arranged at intervals from each other in a direction perpendicular to the paper surface of FIG. These peeling claws 32 are swingably supported by support shafts 230 fixed to support brackets 37 and 37a (rear side not shown) provided on the near side and the back side. Also, a plate 231 fixed to both support brackets 37, 37a and each peeling claw 3
2, each end of the tension spring 38 is locked, whereby
Each peeling claw 32 is given a clockwise rotation behavior in FIG. 3 around the support shaft 230, and the tip of each claw 32 is
Press against the surface of.

Both support brackets 37, 37a are integrated by a connecting plate 239. When the leading end of the transfer paper adhered to the peripheral surface of the fixing roller 12 comes to the leading end of the peeling claw 32, the transfer paper is peeled from the fixing roller 12 by the peeling claw 32, and then guided by the left exit guide plate 33. , As shown by an arrow A1.

Support pins 36, 36a and stopper pins 232, 232a (the back side is not shown) protrude from the inner surfaces of the front and back holding plates 25, 25a of the holding unit 202, respectively.
The above-mentioned support brackets 37, 37a are swingably supported by 6, 36a. The two support brackets 37, 37a abut against the stopper pins 232, 232a.

On the other hand, the aforementioned stay 20 for fixing and connecting the two holding plates 25 and 25a is connected.
A plurality of mounting brackets 233 are fixed to 6, and one or a plurality of magnets 234 are fixedly supported by these.

Normally, the upper ends of the connecting plates 239 of the support brackets 37 and 37a are attracted to the magnets 234 and 234a,
7, 37a are held in the positions shown in FIG.

Here, the transfer paper reaching the tip of the peeling claw 32 is jammed, and the paper is sandwiched between the fixing roller 12 and the peeling claw 32. As a result, the peeling claw 32 and its support brackets 37, 37a are magnetized. The support pins 36,
It rotates around 36a in the counterclockwise direction in FIG. Thereby, the connecting plate 239 of the support brackets 37, 37a is separated from the magnet 234, and the peeling claw 32 is separated from the fixing roller 12. This prevents an excessive load from being applied to the peeling claw 32.

When the transfer paper P is jammed as described above, the fixing device 4 is pulled out as shown by the dashed line in FIG. 2 to remove the jammed paper. Proper number of leaf springs 39 supported by 201
The connection plate 239 and each support bracket 37, 37a are pushed clockwise in FIG.
The connecting plates 239 of the 37 and 37a are attracted and held by the magnet 234, and the tip of the peeling claw 32 is pressed against the peripheral surface of the fixing roller 12. When the jammed paper is removed in this manner, the peeling claw 32 is automatically set at a predetermined position.

The position of the tip of the peeling claw 32 in contact with the surface of the fixing roller 12 is within a range in which the peeling function for transfer paper is not impaired.
It is desirable to be as far away from the nip 220 as possible. This is because the transfer paper is fixed by the
Encourage the transfer paper to separate as much as possible,
This is so as not to contact with. Transfer paper peels nail 32
This is because there is a possibility that the toner image immediately after fixing may be disturbed when the toner image is strongly applied.

Further, it is desirable that the transfer paper guide surface 236 of the peeling claw 32 be as close as possible to the tangent to the surface of the fixing roller passing through the tip of the claw 32. In this way, the transfer paper adhered to the fixing roller 12 can be smoothly separated without applying a large external force.

The transfer paper on which the toner image is formed passes through the guide surface 236 of the peeling claw 32, so that the toner does not adhere here,
The peeling nail 32 needs to be configured. In order to achieve this object, the surface of the peeling claw 32 may be coated with a release material made of, for example, Teflon. However, in order to coat such a release material by baking, the peeling claw 32 must be made of a resin having high heat resistance, for example, a resin having heat resistance of about 280 ° C. or more, and such a resin is generally expensive. .

Therefore, in the illustrated example, the peeling claw 32 is divided into a portion 237 near the guide surface 236 and other portions as shown by a chain line in FIG.
238 and these are made of different resins.
That is, the former is composed of a resin having excellent heat resistance, and the latter is composed of a low-priced resin that is slightly inferior in heat resistance, and these are integrated, and only the former part 237 is coated with a release material. . In this way, the guide surface 236 is coated with a release material to prevent the toner from adhering, and the other portions 238 where the toner does not easily adhere or do not cause a problem can be made of inexpensive resin. And cost reduction can be achieved.

When the leading end of the transfer paper exiting the nip 220 adheres to the surface of the pressure roller 13 and is conveyed, the leading end of the transfer paper is
The guide plate 41 which is separated from the roller 13 by the roller 40 and then supports the separation claw 40, and the above-described right exit guide plate 42
And is fed between the transport rollers 34 and 35 (arrow A2).

The guide plate 41 is fixed to a guide plate bracket 44, and the bracket 44 is attached to the stay 203 by a pin 240 via an arrow B.
Or it is supported rotatably in the opposite direction. When the guide plate bracket 44 is closed as shown in FIG. 3, the guide plate 41 integral with the guide plate bracket 44 is engaged with stoppers 241, 241a (rear side not shown) protruding from the inner side surfaces of the upper holding plates 25, 25a. It is positioned.

A handle cover 45 is integrally fixed on the upper side of the guide plate bracket 44, and when the transfer paper is jammed between the fixing roller 12 and the pressure roller 13, the handle 242 of the handle cover 45 is held and held. Cover 45, guide plate bracket 44, and guide plate
Rotate 41 in the direction of arrow B to fix the fixing roller 12 and the pressure roller.
Open the upper part of 13 to process the jam paper. Handle cover 45
Is to prevent the bracket 44 heated to a high temperature from directly touching the hand.

The handle cover 45 and the guide plate bracket 44 normally occupy the closed position shown in FIG. 3, and the fixing operation is performed in this state. At this time, the upper region of the fixing roller 12 and the pressure roller 13 is the handle cover 45 and the bracket 44. The following problems occur when the container is closed.

That is, when the transfer paper P passes through the nip 220, moisture evaporates, and when a large number of transfer papers are continuously passed, a large amount of moisture evaporates. At this time, if the area above the nip 220 is closed, the vicinity of the nip 220 is filled with saturated steam. Therefore, the water vapor is rapidly absorbed again into the transfer paper from which the water has been evaporated, and the water adheres. As a result, undulations occur in the transfer paper, and if such undulations occur, the transferability of the transfer paper deteriorates, which causes a jam. In particular, in order to perform double-sided copying, the transfer paper is re-fed to the paper re-feeding device 7 (first
(Fig. 1), and the sheet is fed again, the transfer sheet is likely to be wrinkled.

In the fixing device 4 shown therein, one or a plurality of vapor release holes 243 are formed in the handle cover 45, the guide plate bracket 44, and the guide plate 41, and the vapor is released therethrough, and a large amount of water vapor is transferred to the transfer paper. The problem of sudden reabsorption is prevented. Escape hole 2 in the area directly above nip 220
It is desirable to form 43 in a concentrated manner so as to enhance the effect of releasing steam.

The left and right outlet guide plates 33 and 42 are fixed to stays 206 and 207 of the upper support unit 202, respectively.

Further, one of the transport rollers 34 is supported by each of the holding plates 25 and 25a of the holding unit 202, and is driven to rotate by a driving device on the copying machine main body side.

On the other hand, the plurality of mounting brackets 233 fixed to the stay 206 are formed with a notch-shaped support portion 244, and the shaft 245 of the driven transport roller 35 is rotatably supported via a bearing. . Thus, the shaft 245 of the transport roller 35 is
The free end side of an appropriate number of leaf springs 48, which are supported so as to be able to approach or separate from the pair of conveying rollers 34 and one end of which is fixed to the mounting bracket 233, presses against the shaft 245, whereby the conveying rollers 35 is pressed against the convey roller 34 of the other party. A tangential line t passing through a contact portion of the paired conveying rollers 34 and 35 passes through a right side in FIG.
4,35 positions are set. This is because silicone oil as a release agent is applied to the surface of the fixing roller 12 as will be described later, and the silicone oil accumulates in a portion where the peeling claw 32 contacts the surface of the fixing roller 12. This is a measure for preventing the rear end of the transfer paper from contacting the oil reservoir O. That is, when the trailing end of the transfer paper transported between the transport rollers 34 and 35 passes through the nip portion 220 and is in a free state, if the oil sump O is near the tangent t, the transfer is performed. The rear end of the paper comes into contact with the oil sump O, and the transfer paper is contaminated with oil. To prevent this, the tangent t, which is the direction in which the transfer paper is drawn by the transport rollers 34 and 35, is the contact point between the peeling claw 32 and the fixing roller,
That is, it passes through the right side away from the oil sump O portion.

The drive-side transport roller 34 is made of a heat-resistant elastic body, and a low-friction member, for example, a Teflon tube is laminated on the surface of the driven-side transport roller 35.

By reducing the surface frictional force of the transport roller 35 as described above, the following advantages can be obtained. That is, the nip
When the leading edge of the transfer paper exiting 220 is fed between the two transport rollers 34 and 35, the leading edge may hit the peripheral surface of the transport roller 35, and at this time, the peripheral surface is formed smoothly. Therefore, the leading end of the transfer paper that has hit the transport roller 35 can smoothly slide on the peripheral surface and enter between the transport rollers 34 and 35. If the surface of the transfer roller 35 is rough and the coefficient of friction with the transfer paper is large, the leading end of the transfer paper that has hit the roller 35 temporarily stops, and at this time, the leading end may be broken.

As described briefly above, the surface of the fixing roller 12 is coated with silicone oil as a release agent for preventing toner from adhering. Next, a configuration related to this will be clarified.

As shown in FIG. 1, an oil tank 8 containing silicone oil is arranged in the copying machine main body 100, and the oil in this tank is pumped up through a supply conduit 247 by a pump (not shown).

The supply conduit 247 extends to the fixing device 4 as shown by a chain line in FIG. 5, and the silicone oil flows down from the supply port 49 thereof.

On the other hand, as shown in FIG. 4 and FIG.
A gutter-shaped oil guide 50 is fixed to the base support plate 26 on the near side of 201, and the oil flowing down from the supply port 49 is delivered to one end of the oil guide 50. The other end of the oil guide 50 penetrates the base support plate 26, and both base support plates 26, 2
6a protrudes into the area between, below which both base support plates
An oil sump 52 (FIG. 3) is provided between 26 and 26a (the oil guide 50 is not shown in FIG. 3).

The silicone oil delivered to the oil guide 50 flows to the other end of the guide 50, and flows down to the oil sump 52 from a hole 248 formed in the bottom surface of the other end (FIGS. 5 and 8). The oil comp 52 extends in a direction perpendicular to the paper surface of FIG. 3 and is located opposite the fixing roller 12. An oil impregnated member 53 made of felt or the like is provided around the oil sump 52.
There is no impregnating member 53 in the portion facing the hole 248 of the 50, so that the silicone oil sulfided from the hole 248 flows into the oil sump 52 as it is.

A predetermined amount of silicone oil is stored in the oil sump 52 and is supplied to the oil impregnating member 53 from a plurality of oil supply holes 249 (FIG. 8) formed in a wall of the sump 52 facing the fixing roller 12. You. This impregnating member 53 is a fixing roller
The silicone oil impregnated in the member 53 is applied to the surface of the fixing roller 12 while being pressed against the surface of the fixing roller 12.

As can be seen from FIG. 8, the supply of silicone oil from the oil guide 50 to the oil sump 52 is controlled by the oil sump.
This is performed in the area on the front side of 52, and the silicone oil supplied to the sump 52 flows out through the oil supply hole 249 while flowing to the slightly lower side as shown by the arrow S in FIG. At this time, the oil supply hole 24 formed on the near side
The size of the oil supply hole 249 formed on the back side is larger than that of the fixing roller 12, and a uniform amount of silicone oil is applied over the longitudinal direction of the fixing roller 12.

As shown in FIG. 3, a relay oil impregnating member 54 made of felt or the like is arranged in the oil sump 52. The impregnating member 54 is immersed in the oil in the oil sump 52, and the upper part thereof is formed as described above. It is in contact with the oil impregnated member 53.

If the above-described relay oil impregnating member 54 is not provided, when the copying machine is left unused without being used for a long time, no silicone oil is supplied to the oil sump 52, and furthermore, the oil impregnating member
As the oil contained in 53 moves downward, the fixing roller
At the portion of the oil impregnated member 53 facing 12, almost no silicone oil is present. Therefore, if the copying operation is started in this state, the fixing roller 12
The so-called offset phenomenon in which the oil is not applied to the toner and the toner adheres to the surface thereof is remarkable.

Therefore, the relay oil impregnating member 54 is provided as described above, and the silicone oil stored in the oil sump 52 is sucked up by the impregnating member 54, and is always supplied to the oil impregnating member 53, so that the copying operation can be started at any time. Oil can be immediately applied to the surface of the fixing roller 12.

A support plate 55 fixed to the base unit 201 in a manner described later is located on the left side of the oil sump 52, as shown in FIG. 3 and schematically shown in FIG. Arms 58, 58a are swingably supported by ears 250, 250a via pins 57, 57a, and an oil sump 52 is fixed to the lower portion of these arms 58, 58a. Base ends of a pair of leaf springs 56 and 56a are fixed to the support plate 55, and their free ends are in pressure contact with a sump bracket 251 fixed to the oil sump 52. For this reason, the oil sump 52 supported by the pair of arms 58, 58a is urged toward the fixing roller 12 by the leaf springs 56, 56a, and the oil impregnated member 53 is pressed against the surface of the fixing roller 12, as described above. Then, silicone oil is applied to the fixing roller surface 12.

As shown in FIG. 3, blade holders 61, 61a are swingably supported on the lower ear portions 252, 252a via the pins 60, 60a (the back side is not shown), as shown in FIG. These holders
The metering blade 59 is fixed to 61 and 61a.
Each blade holder 61, 61a and the support member 55 have a tension spring 62
Each end of the metering blade
59 presses against the surface of the fixing roller 12.

The metering blade 59 is located downstream of the oil sump 52 in the rotation direction of the fixing roller 12, and regulates the amount of silicone oil applied to the surface of the fixing roller 12 by the oil impregnating member 53 to an appropriate amount.

The fixing roller 12 coated with an appropriate amount of silicone oil by the regulating action of the metering blade 59
At 220, the toner image on the transfer paper is fixed as described above. At this time, the offset phenomenon in which the toner moves to the fixing roller 12 side is suppressed by the action of the applied silicone oil. However, it is generally unavoidable that a small amount of toner and paper dust adhere to the surface of the fixing roller 12 after the transfer paper has passed, and therefore, the surface of the fixing roller 12 is located at a position downstream of the nip 220. The cleaning blade 63 pressed against the toner removes toner and paper dust adhering to the surface of the fixing roller 12.

The cleaning blade 63 is provided on the upper edge 250 of the support plate 55,
The fixing roller 12 fixed to the holder 64 fixed to 250a
Is set in the range of 0.5 to 1.5 mm. The digging amount referred to here is an amount by which the blade 63 interferes with the fixing roller 12 when the blade 63 cannot apply an external force by the fixing roller 12.

When the toner and paper dust on the surface of the fixing roller 12 are removed by the cleaning blade 63, the silicone oil on the surface of the fixing roller is also scraped off at this time, and the oil is removed from the front and rear ends of the cleaning blade 63. Leaves 63 and flows down. At this time, if the oil falls on the oil impregnated member 53, since the oil and toner are mixed in the oil, the oil impregnated member 53 is contaminated by the oil and clogging and the like. Oil cannot be supplied stably to 12.

Therefore, in this embodiment, as shown in FIG. 10, side blades 65 and 65a are provided which are pressed against the front side portion and the rear side portion of the fixing roller surface, and the silicone oil flowing down from both ends of the cleaning blade 63 is provided. The fixing roller 12 is caused to flow toward both journal portions 209 and 209a, and is received by an oil receiver 68 supported in a manner described later. By guiding the silicone oil to the near side and the back side by the side blades 65 and 65a in this way, it is possible to prevent the oil from flowing down onto the oil impregnated member 53.

As can be seen from FIG. 3, each side blade 65, 65a is fixed to the aforementioned cleaning blade holder 64 via a support piece.

The silicone oil collected in the oil pan 68
As shown in FIG. 10 and FIG. 10, the above-described oil pan 69 disposed below the outlet hole 253 formed in the bottom wall thereof.
The oil then flows from the outlet hole 254 of the oil pan 69 to the recovered oil pan 7 further disposed therebelow.
And flows through a discharge hole 72 to a receiving member 71 provided in the copying machine main body 100, and through a discharge conduit 256 connected to the member 71, the oil tank 8 described above.
(FIG. 1).

As shown in FIGS. 5 and 11, the recovered oil pan 70 is integrally fixed to the base support plate 26 on the front side of the base unit 201 via a bracket 257.

Since the receiving member 71 is fixed to the copying machine main body as described above, when the fixing device 4 is pulled toward the front side as shown by a chain line in FIG. 2, below the discharge hole 72 of the recovery oil pan 70, If there is no oil catcher and this hole 72 is left open, the oil will flow down from the discharge hole 72 to the floor below and will be contaminated.

In the fixing device 4 shown in FIG.
As shown in FIG. 11, a seal member 73 is rotatably supported by a recovered oil pan 70 via a pin 258. The sealing member 73 is given a rotating behavior in the clockwise direction in FIG. 3 by a spring (not shown). However, when the fixing device is pushed inward and is set,
The release member 76 supported on the 100 side contacts the upper portion of the seal member 73, and holds it at the position shown by the solid line in FIG. 3 against the spring force. For this reason, the lower seal portion 25 of the seal member 73
9 is separated from the discharge hole 72 of the recovery oil pan 70, and this hole 72 is opened. Therefore, the oil in the recovered oil pan 70 flows down to the receiving member 71 through the discharge hole 72 as described above.

When the fixing device 4 is pulled out to the near side, the sealing member
Since the member 73 also moves to the near side, the member 73 comes off the release member 76. For this reason, the sealing member 73
3 rotates clockwise in FIG. 3 and becomes a state shown by a broken line, and the seal portion 259 closes the discharge hole 72. Therefore, the oil is prevented from flowing down from the hole 72.

If the fixing device 4 is pushed in again and set, the sealing member
73 is pressed by the release member 76, returns to the position of the solid line,
The discharge hole 72 is opened.

As the release member 76, a roller, a ball bearing, or the like can be advantageously used.

By the way, the amount of silicone oil applied to the fixing roller 12 is regulated by the metering blade 59, but excess oil flows from the front and rear ends of the metering blade 59 to the fixing roller surface, and this is pressurized. The transition to the end region of the surface of the roller 13 is made. Then, there is a possibility that the pressure roller 13 slips with respect to the transfer paper, or oil droplets are scattered outside the fixing device due to centrifugal force caused by rotation of the pressure roller 13.

Therefore, as shown in FIGS. 3 and 12, weir members 83, 83a whose upper end surfaces are inclined outward are pressed against the front and rear end regions of the surface of the pressure roller. 13
The oil attached to the end region is scraped off, and the scraped oil is received by the oil pan 69, thereby preventing the above-mentioned problem from occurring. Weir member 8
3,83a is fixed to the oil pan 69 via a fixing member.

As the weir members 83, 83a, for example, an elastic synthetic resin sheet such as Mylar (trade name) can be used.

By the way, the oil impregnated member 53, the metering blade 59, the cleaning blade 63, and the like deteriorate with time, and therefore need to be replaced with new ones as needed. Such a replacement operation requires the fixing device 4 to be in the second position.
It is common to pull the device 4 out of the copier main body 100 as shown by a chain line in the figure, or remove the device 4 from the copier main body 100. However, in a conventional fixing device, oil spills during this work, and There was a risk that the carpets etc. would be soiled.
Further, even if the fixing device is detached from the copying machine main body 100, there is no space for mounting the fixing device, and it may be difficult to perform the operation.

Therefore, in the illustrated fixing device 4, as described below, the above-described members that need to be replaced are integrally assembled as an oil application unit 84 (FIG. 3), and the fixing device 4 is attached to the main body of the copying machine. It is configured so that a predetermined replacement operation can be performed without worrying about dripping of the oil simply by pulling out the line as shown in FIG.

3 and 9, concentric pivot pins 66, 66a are protrudingly provided on the inner surface of the front and rear support plates 26, 26a of the lower support unit 201. The lower ears 260 and 260a of a cover 90 located on the left side of the fixing device 4 are rotatably supported by the cover 90.
68 are integrally fixed by screws 261 and 261a. The upper portion of the cover 90 is fixed to the stay 67 by screws 262. Thus, the cover 90 is usually fixed to the lower support unit 201.

An oil application unit 84 is located inside the cover 90, and the unit 84 includes the above-described support plate 55 and the above-described various components attached thereto. In other words, this unit 84 includes the support plate 55 and the arm 5
Oil sump 52, oil impregnated members 53, 54, leaf springs 56, 56a, cleaning blade 63, supported via 8,58a,
In addition to the holder 64 for holding this, the side blades 65 and 65a supported by it, the metering blade 59, the holders 61 and 61a for supporting it, and the spring 62, the bracket 26 is attached to the support plate 55.
It is composed of the above-mentioned springs 39 and the like supported via 3 and these are integrally assembled, and the support plate 55 is fixed to the cover 90 by screws 264 and 264a.

When replacing parts such as the metering blade 59,
After the fixing device 4 is pulled out to the near side as shown by the chain line in FIG. 2, the screw 262 fixing the upper portion of the cover 90 is removed. As a result, the cover 90 is released from its fixed state,
90 is rotated counterclockwise about the pivot pins 66 and 66a to the position shown by the chain line in FIG.

Next, remove the screws 264 and 264a to remove the oil application unit 84.
The fixed state to the cover 90 is released, and the unit 84 is lifted upward. Then, the left and right sides of the unit 84 are reversed, and the fork portion 265 formed at the lower portion of the support plate 55 is
As shown in FIG. 3, the unit 84 is fitted to the stay 67, and the unit 84 is supported by the stay 67. By doing so, the cleaning blade 63, the metering blade 59, the oil impregnated member
53 and the like are exposed to the outside, so they can be exchanged for new ones as they are.

As described above, the parts can be replaced without removing the fixing device 4 from the copier main body 100, and the parts can be replaced simply by pulling the fixing device 4 toward the front side, and a large space for this work is not required. Moreover, as can be seen from FIG. 13, the stay 67
The open cover 90 is located below the oil application unit 84 supported by the oil supply unit 84. Therefore, even if silicone oil drips from the unit 84 at the time of component replacement, the silicone oil is received by the cover 90 and is received by the oil receiver 68. Can flow down. Therefore, there is no concern that the floor on which the copying machine is arranged, the carpet, and the like are soiled with oil.

By the way, when the fixing device 4 is pushed into the back side and is set in the copying machine main body 100, the fixing device 4 should not be unintentionally slid forward and pulled out due to slight vibration or the like.

Therefore, in this embodiment, the lock device 266 shown in FIGS. 14 and 15 is provided. Hereinafter, this will be described.

A pin 267 and a shaft 79 protruding toward the near side are fixed to a lower portion of the base support plate 26 on the near side of the base unit 201, and the pin 267 and the shaft 79 are horizontally slidable by a sliding member 81. Are slidably fitted in the long holes 268 and 269 formed in the holes. Also, the pin 267 and the slide member 81
Each end of the tension spring 270 is locked, whereby the slide member 81 is urged rightward in the figure, the pin 267 hits the left end of the elongated hole 268, and the slide member 81 stops at the illustrated position. ing.

The slide member 81 has a horizontal tongue 271,
, A latch 78 is fixed so that the position can be adjusted.

An operation lever 80 is fixed to the shaft 79, and its protrusion 272 is provided.
Abuts against a pressure piece 82 formed of a roller or a ball bearing supported by a slide member 81.

On the other hand, a lock member 77 made of, for example, a ball bearing is fixedly supported on the copying machine body 100.

When the fixing device 4 is pushed inward and set in the copying machine main body 100, the lock groove 273 formed at the end of the latch 78 engages with the locking member 77 on the copying machine main body side. For this reason, even if a force to the near side indicated by the arrow A acts on the fixing device 4, the device 4 is not pulled out to the near side and is set at a predetermined position. That is,
The fixing device 4 is locked.

When the fixing device 4 is pulled out to the front, the operator
The lever 80 is rotated clockwise in FIG. 15 by grasping the knob 274 of the lever 80. Then, the protruding portion 272 of the lever 80 presses the pressing piece 82 leftward in the drawing. As a result, the slide member 81 slides to the left together with the latch 78 against the action of the spring 270, and the lock groove 273 at the tip of the latch 78 as shown by the broken line in FIG. Get off. Therefore, if the fixing device 4 is pulled toward the user (in the direction of arrow A), the fixing device 4 can be pulled out without any trouble.

There is no need to operate the lever 80 when pushing the fixing device 4 inward. That is, with the pushing operation of the fixing device 4, the cam surface 275 of the latch 78 hits the lock member 77, whereby the latch 78 and the slide member 81 are retracted in the manner shown in the drawing, and the cam surface 275 rides over the lock member 77. Then, the slide member 81 and the latch 78 return to the position shown by the solid line in FIG.
And the fixing device 4 is locked.

By the way, when the fixing device 4 is set by pushing it inward, it is necessary to connect the connector on the fixing device 4 side and the connector on the copier body side to supply power to the fixing device 4 side and supply power to the heater 2 and the like. . On the other hand, when the fixing device 4 is pulled out to the near side, the two connectors are disconnected from each other. When the fixing device 4 is pulled out in this manner, the operator can reach into the copying machine main body side, so that the worker may touch the connector on the copying machine main body side, which is very dangerous.

Therefore, in the illustrated fixing device 4, when the fixing device 4 is pulled out to the near side, the connector on the copying machine main body side is automatically closed by the shield, so that there is no danger of directly touching the connector.

FIG. 16 shows a state in which the fixing device 4 is pushed inward and set in the middle, and FIG. 17 shows a state in which the fixing device 4 has been set.

The rail 215 of the guide rail device 213 described above projects further back than the base support plate 26a on the back side of the base unit 201, and the guide member 86 is fixed thereon. The guide member 86 has a guide groove 276 that opens substantially toward the back in a hopper shape. Reference numeral 280 denotes a connector on the fixing device 4 side fixed to the base support plate 26a on the back side.

On the other hand, the frame side plate 278 of the copying machine main body 100 is located further back than the base support plate 26a on the back side.
A connector 277 on the copying machine main body side is fixedly mounted on the frame, and the connector 277 is opposed to a window hole 279 formed in the frame side plate 278.

A plate-shaped shield 92 is pivotally supported on the copying machine main body 100 via a pivot pin 281. The shield 92 is urged counterclockwise by a spring (not shown). The shield 92 has a guide pin 87 projecting therefrom.

When the fixing device 4 is pulled out to the front side or when the fixing device 4 is not completely set as shown in FIG. 16, that is, when the guide member 86 does not touch the guide pin 87 of the shield 92, the shield 92 Contacts the connector 277 on the copying machine main body side by the above-mentioned spring, and closes the connector 277. For this reason, even if an operator puts his hand on the back side of the copying machine main body, he does not directly touch the connector 277 and safety is ensured.

When the fixing device 4 is pushed inward as shown in FIG. 16, the guide pin 87 of the shield 92 enters the guide groove 276 of the guide member 86, and 87-1, 87-2, 87-3, 87- 4 on the inclined guide surface 282 of the guide groove 276. This causes the shield 92 to rotate clockwise about the pivot pin 281 to open the connector 277. Then, when the connector 277 is completely opened as shown in FIG. 17, the connector 280 on the fixing device side is fitted into the connector 277 on the copier body side, and both are connected.

When the fixing device is pulled out again, the shield 92 becomes a guide member.
86 is released sequentially, and the 16th
The connector 277 is closed as shown.

The guide member 86 may be provided on a portion of an appropriate fixing device other than the rail 215.
Can be fixed in place other than.

In FIG. 3, only the outline of the positional relationship among the connector 277, the guide pin 87, the pivot pin 281 and the shield 92 is shown by a chain line.

Although the embodiment of the fixing device mounted on the electronic copying machine has been described above, the present invention can be applied to a fixing device in various image forming apparatuses other than the copying machine.

[Effect of the invention]

According to the fixing device of the present invention, usually, each bearing of the fixing roller is supported by being sandwiched between each base support plate and each press plate, and when the fixing roller is removed, each press plate is separated from the base support plate. Thus, each bearing can be removed from each notch of each base support plate, and the fixing roller can be easily removed. Moreover, even if the fixing roller is in a hot state, the roller can be easily removed, and the working time can be greatly reduced.

Further, since each bearing of the fixing roller is held by each base support plate and each pressing plate, the positioning accuracy of the fixing roller is enhanced, and the fixing roller can be rotated in a stable state.

Furthermore, since each holding plate fixed to each base support plate is bridged over the opening of each notch, when pressure from the pressing means acts on each base support plate, the holding plate is
The base support plate is prevented from being deformed such that the notch formed in the base support plate is greatly expanded. Each holding plate serves to reinforce each base support plate that has been pressed by the pressing means. As a result, the position of the pressure contact portion between the fixing roller and the pressure roller can be prevented from being largely shifted, and the recording material can always be conveyed correctly.

Further, since each bearing of the fixing roller pressed by the pressing means is received by the base support plate, a large pressure is not applied to the pressing plate, so that the pressing plate is greatly deformed or damaged. Troubles can be prevented. The base support plate and the holding plate cooperate with each other to effectively suppress their respective deformations. Moreover, even when the presser plate is removed from the base support plate while the pressurizing roller is pressed against the fixing roller by the pressurizing device, the pressure from the pressurizing device originally hardly acts on the presser plate. There is no problem that the roller jumps out of the notch of the base support plate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the internal structure of an electronic copying machine, FIG. 2 is an external perspective view of the electronic copying machine shown in FIG. 1, and FIG. Remove the base support plate and the holding plate on the side,
FIG. 4 is a front view of the fixing device, in which a lock device and an oil guide are omitted, and a part thereof is shown in a cross section. FIG. 4 is a perspective view showing a relative relationship among an oil guide, a support device, and a fixing roller. FIG. 5 is a view in which other elements are omitted for easy understanding of the drawing. FIG. 5 is a front view of the fixing device, and FIG.
FIG. 6 is a view in which the lock device shown in FIG. 15 is omitted, FIG. 6 is a horizontal sectional view showing a supporting mode of the fixing roller, and FIG. 7 shows a relative relationship between the fixing roller and the entrance guide plate. FIG. 8 is a perspective view of an oil sump, FIG. 9 is a plan view showing a simplified configuration of an oil application unit and related components, and FIG. FIG. 11 is a simplified cross-sectional view of each member that receives the removed silicone oil, FIG. 11 is a plan view of a recovered oil pan, and FIG. 12 is a simplified configuration of removing the silicone oil attached to the pressure roller. FIG. 13 is a view similar to FIG. 3, showing a state in which the oil application unit is detached and the stay is supported by a stay, FIG. 14 is a partial cross-sectional plan view showing the lock device, FIG. Is a front view of the locking device, and FIGS. 16 and 17 Is a partial cross-sectional plan view for explaining the operation of the shield connector shield. 2 ... heater, 4 ... fixing device 12 ... fixing roller, 13 ... pressure roller 25, 25a ... holding plate, 26, 26a ... base support plate 30, 30a ... bearing 100 ... body, 200 ... Supporting devices 209,209a ... Journal section, 210,210a ... Notch 211,211a ... Presser section, Y ... Pressure receiving section

Claims (1)

(57) [Scope of request for utility model registration] A fixing roller that is heated by a heater; a pressure roller that extends in parallel with the fixing roller and is in contact with a peripheral surface of the fixing roller; A pressing unit for pressing the peripheral surfaces of both rollers against each other, and a supporting device for rotatably supporting the fixing roller. The fixing roller heated by a heater and the pressing roller pressed against the fixing roller are rotated. A fixing device of an image forming apparatus for fixing a toner image on a recording material by passing a recording material carrying a toner image between these rollers. A pair of base support plates provided with notches into which the bearings attached to the end journals are fitted, and a pair of holding plates fitted into the respective notches and pressing the respective bearings of the fixing roller held in the notches. And Each notch has a substantially semicircular shape in which a direction substantially perpendicular to a direction in which pressure is applied to the fixing roller from the pressing means is an open portion so that each bearing of the fixing roller can be detachably held. And a pressing force receiving portion that receives each bearing pressed by the pressing means at a portion opposite to the pressing portion of the fixing roller and the pressing roller with respect to the center axis of the fixing roller. Each of the pressing plates is bridged over the opening of each notch and presses each bearing of the fixing roller from a direction substantially perpendicular to a direction in which pressure is applied to the fixing roller from the pressing unit. A fixing device having a pressing portion and being detachably fixed to a base member so that each bearing of the fixing roller can be attached to and detached from each notch.