JPH0477316B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention provides a method for transferring a toner image onto a recording paper by passing a recording paper carrying a toner image between a heating roller and a pressure roller that are in rolling contact with each other in a pair. When the recording paper that has been fixed and has passed between the heating roller and the pressure roller adheres to the heating roller, the attached recording paper is removed by at least one peeling claw whose tip is in contact with the surface of the heating roller. The present invention relates to a fixing device that is separated from a heating roller and at least a portion of the periphery of the heating roller is covered with a heat insulating cover.

Prior Art In the above-mentioned type of fixing device used in various recording devices such as electronic copying machines, electrostatic recording devices, and printers, the recording paper is caught between the heating roller and the tip of the peeling claw, which causes trouble in conveying the recording paper. There is a possibility that this may occur. Therefore, a fixing device has been proposed in which the peeling claw is retracted from the heating roller together with the heat insulating cover when a trouble occurs in conveying the recording paper. However, with this configuration, the tip of the retracted peeling claw is exposed to the outside of the fixing device, and when the operator removes the troublesome recording paper (jam paper),
There is a risk of touching the sharp tip of the peeling nail. Not only that, but by opening the insulation cover,
Since the heating roller heated to a high temperature is largely exposed, there is a risk that the operator may accidentally touch it.

Purpose It is an object of the present invention to provide a fixing device that eliminates the above-mentioned conventional drawbacks and can safely and easily remove jam paper.

Configuration In order to achieve the above object, the present invention, in the fixing device of the type described at the beginning, places at least a portion of the heat insulating cover on the opposite side of the peeling claw with respect to a line connecting the axes of the heating roller and the pressure roller. a first stopper that supports the cover rotatably around a fulcrum and stops the cover at a maximum open position where the tip of the peeling claw is not exposed to the outside of the heat insulating cover;
a biasing unit that rotatably supports the peeling claw on a rotatable heat insulating cover portion via a support shaft, and biases the peeling claw in a direction in which a tip of the peeling claw contacts a heating roller; a second stopper for regulating the rotation range of the peeling claw, and a second stopper for regulating the relative position between the tip of the peeling claw and the surface of the heating roller when the heat insulating cover is rotated to the closed position. We propose a configuration that includes a positioning member.

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

In FIG. 1, a photosensitive drum 1 is rotated counterclockwise in the figure, and a toner image is formed on its surface. This toner image is transferred onto recording paper 2, and then this recording paper 2 is separated from photoreceptor drum 1, conveyed in the direction of arrow A by conveyance belt 3, and sent to fixing device 4. Toner remaining on the surface of the photoreceptor drum after the toner image has been transferred is removed by a cleaning device 5.

The fixing device 4 includes a heating roller 6 that extends perpendicularly to the plane of the paper, and a pressure roller 7 that forms a pair with the roller 6 and rolls into contact with the roller 6 while pressing against each other. A heater 8 is housed inside the heating roller 6, and the heating roller 6 is heated by this. A heater is also installed inside the pressure roller 7, and the pressure roller 7
It can also be configured to heat directly.

The heating roller 6 is rotated counterclockwise by a drive device (not shown), and the pressure roller 7 is rotated clockwise. At this time, the recording paper 2 carrying the toner image is pressed against the heating roller 6. It is fed between roller 7 and passes between both rollers. At this time, the toner image on the recording paper 2 is fixed onto the recording paper mainly by the heat from the heating roller 6 and the pressure from both rollers.

When the leading edge of the recording paper that has passed between the heating roller 6 and the pressure roller 7 is attached to the heating roller 6, the leading edge 9a of the recording paper is removed by one or more peeling claws 9 whose leading edge 9a is in contact with the surface of the heating roller 6. , the attached recording paper is peeled off from the heating roller 6. Similarly, when the leading edge of the recording paper 2 comes into close contact with the circumferential surface of the pressure roller 7, it is peeled off from the pressure roller 7 by at least one peeling claw 10 on the lower side that is in contact with the pressure roller 7. The recording paper discharged from the fixing device 4 in this manner is guided by the upper guide plate 11 and the lower guide plate 12, and is further fed by conveyance rollers 13 and 14 rotating in the direction shown by the arrow. receive.

In addition, 15 is a thermistor that detects the temperature of the heating roller 6, 16 is a roller cleaning blade that cleans the toner attached to the heating roller 6, and 17 is a mold release agent 18a supplied from a tank 18 on the circumferential surface of the heating roller 6. The coating felt 19 is a metering blade that evens out the applied mold release agent. Further, 20 indicates a cleaning roller that cleans the peripheral surface of the pressure roller 7, and 21 indicates an oil pan that receives the dropping agent.

The heating roller 6 is heated to a high temperature by the heater 8, but if that heat is directly released outside the fixing device, not only will the heat be lost, but there is a risk that the heat will have an adverse effect on elements around the fixing device. There is. Therefore, at least a part of the area around the heating roller, in this example, the area above the heating roller 6 is covered by the heat insulating cover 2.
Covered by 2. Although the heat insulating cover 22 may have a single layer structure using a single heat insulating material, in the illustrated example, the heat insulating cover 22 is structured in a multilayer structure using the first heat insulating material 23 and the second heat insulating material 24. .
Further, a side plate 25 (only one of which is shown in FIG. 1) of the fixing device is located at the ends of both the heat insulating materials 23 and 24 in the direction perpendicular to the paper surface of FIG. 1 (lateral direction). In this way, the upper region of the heating roller 6 is surrounded by the first heat insulating material 23 and both side plates 25, and the first and second heat insulating materials 23, 24 and both side plates 25
5 defines an airflow passage 26.
Air flowing into the air flow passage 26 from the air inlets 28 and 32 flows out from an air outlet 29 formed in the side plate 25. By causing air to flow in this way, the heat insulating effect of the heat insulating cover 22 is enhanced. A blower (not shown) may be connected to the air outlet 29 to forcibly suck the air in the air flow path 26, and the side plate 25 is also desirably made of a heat insulating material.

The recording paper 2 that has left the fixing device 4 has its feeding direction controlled by the recording paper reversing device 30 as follows.

In FIG. 1, 33 is a drive roller that is driven to rotate in a clockwise direction, and 34 and 35 are first and second movable rollers that are paired with the drive roller 33 and are rotated in a counterclockwise direction. When the recording paper that has come out of the fixing device 4 should be ejected out of the machine, the first
Then, the second movable rollers 34, 35 are brought to the position shown in solid lines in FIG. As a result, the recording paper 2 is conveyed in the direction of arrow B while being held between the movable rollers 34 and 35 and the drive roller 33, and is guided to the upper and lower guide plates 36 and 37 and the upper end guide surface of the movable guide member 38. The paper is then discharged to a stacker 41 outside the machine by paper discharge rollers 39 and 40.

When the recording sheets are reversed and discharged outside the machine for the purpose of aligning the order of recording sheets written on the stacker 41, the first and second movable rollers 34, 3 are used.
5 are actuated in a direction away from each other, bringing them into the position shown in dotted lines in FIG. At the same time, the movable guide plate 42, which had been in the position shown by the solid line, is moved to the position shown by the chain line. As a result, when the leading edge of the recording paper 2 reaches the reversing device 30, the recording paper is guided by the movable guide plate 42, and the first movable roller 34 and drive roller 33 move to the position indicated by the chain line.
As a result, it is sent upward as shown by arrow C. At this time, the recording paper is inserted between the two upper guide plates 1
Guide plate 1 integrally connected to 1 and 36, respectively.
1a and 36a.

Each roller 43 of the pair of feed-back rollers 43 is attached to the appropriate position of these guide plates 11a, 36a.
a and 43b are supported so as to be able to approach and separate from each other, the roller 43a on the fixed side is rotationally driven in the direction of moving the recording paper backward, and the roller 43b on the movable side is rotatable. When they come into contact with each other through the paper, the recording paper is moved backwards. When the trailing edge of the recording paper passes through the nip composed of the drive roller 33 and the first movable roller 34, each roller 43 of the return roller pair 43, which had been separated from each other until then,
a and 43b come into contact with each other through the recording paper, and the movable guide plate 42 retreats to the position shown by the solid line. As a result, the recording paper is returned in the direction opposite to arrow C.
It is held between the second movable roller 35 and the drive roller 33, and is discharged outside the machine while being guided by the guide surface of the movable guide member 38 and the upper and lower guide plates 36, 37. The ejected recording paper is in an inverted state.

When the pair of feed-back rollers 43 approach each other to return the recording paper, if the movable guide member 38 is rotated to the position shown by the chain line, the recording paper is guided downward by the other pair of guide plates 44. transported towards
This recording paper is again fed to the photosensitive drum 1, and a toner image is transferred again to the surface opposite to the surface to which the toner image was previously transferred, and this is fixed by the fixing device 4. In this way, toner images are formed on both sides of the recording paper.

Furthermore, if the movable guide plate 42 is retracted to the position shown by the solid line, the movable guide member 38 is rotated to the position shown by the chain line, and the first and second movable rollers 34 and 35 are brought to the position shown by the solid line, the fixing device The recording paper 2 that has come out of the paper 4 can be fed directly to the guide plate 44 below. Next, by feeding this recording paper to the photoreceptor drum 1 again, a new toner image can be formed on the same surface to which the toner image was previously transferred, and the toner images are combined on one side of the recording paper. can be formed.

Here, the recording paper is heated by the heating roller 6 of the fixing device 4.
If the jam paper becomes jammed between the jam paper and the peeling claw 9 in pressure contact therewith, or in any other conveyance path, the jam paper can be easily taken out using the structure described below.

In the copying machine shown in FIG.
and the recording paper reversing device 30 form an integral unit 45 as shown surrounded by a chain line, and this unit 45
can be pulled out from the copier body. That is, a guide rail 47 fixed to a support 46 of the unit 45 is supported so as to be slidable in a direction perpendicular to the paper plane of FIG. 1 along a fixed guide rail 48 fixed to the main body of the copying machine. As a result, the entire unit 45 can be pulled out from the main body of the copying machine toward the front side with respect to the page of FIG. The reason for this structure is that if the jam paper stops across both devices 4 and 30, if only one of the devices 4 or 30 is pulled out, the jam paper will be damaged and it will become increasingly difficult to remove it. Because it will be. The rollers 13, 3435, 43 and the guide plates 11, 11a, 36, 36a are the reversing device 30.
The cover 49 is supported by a side plate 49a of a cover 49 that covers the support shaft 3 of the roller 39 as shown in FIG.
9a, so that after pulling out the unit 45 as described above, the cover 49
When opened as shown in FIG. 2, the recording paper reversing device 30
You can easily remove paper that is stuck in the paper.

On the other hand, at least a portion of the heat insulating cover of the fixing device is rotatably supported. In this example,
The first and second heat insulators 23 and 24 are separated into fixed parts 23a and 24a and movable parts 23b and 24b, respectively, and the movable part 23b of the first heat insulator 23 is connected to the fixed part 23a via a hinge 50. It is rotatably supported, and both movable parts 23b and 24b are connected to the fixed part 23.
It is possible to rotate integrally with respect to a and 24a.

FIG. 2 shows the state when the movable parts 23b and 24b are rotated from the closed position shown in FIG. 1 to the maximum open position, and as can be seen from FIG.
The movable parts 23b and 24b of the heat insulating cover 22 are rotatable around a fulcrum located on the opposite side of the peeling claw 9 with respect to a line (not shown) connecting the axes of the heating roller 6 and the pressure roller 7. Supported.

Although the side plates 25 are fixed immovably, the side plates located on both sides of the heat insulating cover 22 are constructed as separate members from the side plates of the entire fixing device, and the side plates on the sides of the heat insulating cover are rotated together with the movable parts 23b and 24b. It may be configured so that it can be moved. Furthermore, 53 and 54 are sealing members that seal between the fixed parts 23a and 24a and the movable parts 23b and 24b, respectively. Made of flexible material.

Further, the peeling claw 9 is rotatably supported by a rotatable heat insulating cover portion via a support shaft 61. In this example, brackets 60 are fixed to each end of the movable portion 23b in the lateral direction, and these brackets 6
The above-mentioned support shaft 61 is fixed to 0, and the peeling claw 9 is rotatably supported on this.

Each end of a tension spring 62, which is an example of a biasing means, is engaged with the first heat insulating material 23 and the peeling claw 9, so that the tip 9a of the peeling claw 9 contacts the heating roller 6. direction (clockwise). When the heat insulating cover 22 is in the closed position as shown in FIG. 1, the tip 9a of the peeling claw 9 comes into pressure contact with the heating roller 6 by the action of the tension spring 62, and serves to peel the recording paper from the heating roller 6.

When recording paper becomes jammed between the tip 9a of the peeling claw 9 and the circumferential surface of the heating roller 6, pull out the unit 45 as described above and remove the cover 4 that covers the reversing device 30.
9 as shown in FIG. 2, then remove the insulation cover 22.
The handle 51 attached to the movable part 24b is lifted upward, and both the movable parts 24b and 23b are rotated as shown in FIG. As a result, the movable part 23b
The peeling claw 9 supported by the movable parts 23b and 24b also rotates, and its tip 9a separates from the heating roller 6. Therefore, the jam paper (not shown) that was wedged between the tip 9a of the peeling claw 9 and the circumferential surface of the heating roller 6 is released, and the operator can remove the paper from the relatively wide space created below the peeling claw 9. , the jam paper can be easily taken out.

Here, when the movable parts 23b and 24b of the heat insulating cover 22 are rotated from the closed position shown in FIG. 1 to the maximum release position shown in FIG. The protrusion 63 of the movable part 23b comes into contact with the first stopper 52, and the movable parts 23b, 24
b stops. The first stopper 52
The positions are set so that when the movable parts 23b and 24b are rotated from the closed position, the movable parts 23b and 24b are stopped at the maximum release position where the tip 9a of the peeling claw 9 is not exposed outside the heat insulating cover 22. ing.

In this way, the movable part 23b of the heat insulation cover 22,
24b is set to a relatively small maximum opening angle to prevent the sharp tip 9a of the peeling claw 9 from being exposed to the outside, thereby preventing the operator who removes the jam paper from touching the tip 9a. be. In addition, since the opening angles of the movable parts 23b and 24b are small, it is possible to prevent the heating roller 6 from being largely exposed outside the heat insulating cover, and it is possible to avoid the possibility that the operator will touch the heating roller 6 at high temperature. Since the heat insulating cover 22 itself has heat insulating properties, no problem occurs even if the operator touches the second heat insulating material 24 on the outside.

As mentioned above, the fulcrums of the movable parts 23b and 24b are located on the opposite side of the peeling claw 9 with respect to the line connecting the axes of the heating roller 6 and the pressure roller 7, so that from the fulcrum to the peeling claw 9 distance is large.
For this reason, although the maximum opening angle of the movable parts 23b and 24b is small, the tip of the peeling claw 9 is connected to the heating roller 6.
can be placed far away from the surface. Thereby, it is possible to prevent a problem in which the workability during jam paper removal is reduced.

Furthermore, even when the movable parts 23b and 24b of the heat insulating cover 22 rotate as shown in FIG. 2, the peeling claw 9 is biased clockwise by the tension spring 62, so that
The sharp tip 9a can be directed toward the inside of the heat insulating cover 22, and the risk of the operator touching the tip 9a of the peeling claw 9 can be more reliably prevented.

When the user releases the handle 51 after taking out the jam paper, both movable parts 23b and 24b return to the normal closed position shown in FIG. Never. Further, a spring (not shown) is provided to urge the movable parts 23b and 24b toward the closed position, and the movable part 23
It is also advantageous to configure b, 24b to more reliably return to the closed position.

By the way, the movable parts 23b, 2 of the heat insulation cover 22
4b to the closed position, if the tip 9a of the peeling claw 9 does not come into contact with the surface of the heating roller 6 in a predetermined positional relationship, the peeling function for the recording paper may deteriorate or the heating roller 6 and the peeling claw 9 are likely to wear out. For example, if the belly portion of the peeling claw 9 hits the surface of the heating roller 6, the recording paper peeling function will be significantly degraded, and the tip 9a will touch the surface of the heating roller 6.
If the parts hit the surfaces too strongly, excessive external force will be applied to them, which will inevitably lead to accelerated wear.

When the insulation cover 22 is brought to the closed position,
Whether or not the tip 9a of the peeling claw 9 properly contacts the surface of the heating roller depends on the support shaft 61 that supports the peeling claw 9.
Therefore, it is necessary to correctly position the support shaft 61 with respect to the heating roller 6. At this time, in the illustrated fixing device, as described above, the pivot point of the heat insulating cover 22 and the support shaft 61 that supports the peeling claw 9 are connected to the line connecting the axes of the heating roller 6 and the pressure roller 7. Since they are located on opposite sides, the fulcrum of rotation of the heat insulating cover 22 and the support shaft 61 are far apart from each other. Due to thermal expansion, variations in the position of the support shaft 61 relative to the heating roller 6 are likely to occur.

Therefore, in the illustrated fixing device, when the heat insulating cover 22 is rotated to the closed position, the member 64 for positioning the support shaft 61 is used to regulate the relative position between the tip 9a of the peeling claw 9 and the surface of the heating roller. , are immovably provided at a position that does not obstruct the advance of the recording paper. When the movable parts 23b and 24b return to the closed position shown in FIG. The tip 9a of the peeling claw 9 can be brought into contact with the surface of the peeling claw 6 in a predetermined positional relationship. This can prevent the deterioration of the recording paper peeling effect of the peeling claw 9 and the acceleration of wear between the peeling claw 9 and the heating roller 6.

Moreover, the movable parts 23b and 24b are opened from the closed position,
When the tip 9a of the peeling claw 9 separates from the heating roller 6, the peeling claw 9 is pulled by the tension spring 62, but if the peeling claw 9 rotates greatly due to this tensile force, the movable part 23b , 24b to the closed position, the tip 9a of the peeling claw 9 interferes with the heating roller 6, making it impossible to reset the movable parts 23b, 24b. The protrusion 9b of the peeling claw 9 is brought into contact with the second stopper 65 attached to the second stopper 65 (the second
(Fig.), the rotation range of the peeling claw 9 is restricted to prevent the claw 9 from rotating more than necessary.

In the illustrated embodiment, the lower peeling claw 10, which is normally in pressure contact with the pressure roller 7, is also used when the movable parts 23b and 24b are rotated from their closed positions, or when the cover 49 is rotated as shown in FIG. When the paper is opened to the open position shown in FIG. 1, it is moved away from the pressure roller 7 in conjunction with this operation, and the jam paper sandwiched between the peeling claw 10 and the pressure roller 7 can be removed.
Furthermore, the pressure roller 7 and the heating roller 6 are configured to be released from the pressure contact state not only when the copying machine is stopped or on standby, but also when removing jam paper, so that the pressure roller 7 and the heating roller 6 are released from the pressed state. This makes it easy to remove the recorded paper.

In the embodiment shown in FIGS. 3 and 4, one end 66a of the leaf spring 66 is fixed to the movable part 23b of the first heat insulating material 23, and the movable parts 23b, 24b of the heat insulating cover 22 are fixed.
When the first stopper 52 is rotated from the closed position shown in FIG. 3 to the open position shown in FIG. It has been done. According to this configuration, when the movable parts 23b and 24b are brought to the fully open position shown in FIG. Therefore, the movable parts 23b and 24b are held at the fully open position. To return the movable part to its fully closed position, it is sufficient to push the movable part downward, whereby the stopper 52 deforms the leaf spring 66 and climbs over the leaf spring 66 again, thereby moving the movable parts 23b, 2
4b can be returned to the closed position shown in FIG.
Also in this case, a pressing member 67 (the fourth
When the cover 49 is rotated from its fully open position to the position shown by the chain line in Figure 4, the pressing member 67 is brought into contact with the movable part 24b and it is automatically moved to its fully closed position. It is advantageous to design it so that it can be rotated.

Effects According to the present invention, at least a portion of the heat insulating cover is rotatably supported, and the cover is
A first stopper is provided to stop the peeling claw at the maximum open position where the tip of the peeling claw is not exposed outside the insulation cover.
Even when the heat insulating cover is opened, the operator can avoid the risk of touching the sharp tip of the peeling claw or the high-temperature heating roller, ensuring safety.

In addition, since the rotation fulcrum of the heat insulation cover is located on the opposite side of the peeling claw with respect to the line connecting the axes of the heating roller and the pressure roller, the distance from the fulcrum to the peeling claw can be increased. Since the maximum opening angle of the heat insulating cover is small, the tip of the peeling claw can be kept far away from the surface of the heating roller.
As a result, it is possible to prevent a problem in which workability is reduced when removing the coyam paper.

Furthermore, since the tip of the peeling claw is biased by the biasing means in a direction in which the tip contacts the heating roller, the sharp tip of the peeling claw is insulated even when the insulation cover is rotated to the maximum open position. It can be directed toward the inside of the cover, and it is possible to more reliably prevent the operator from touching the tip of the peeling claw.

Moreover, when the heat insulating cover is opened to the maximum open position, the peeling claw is prevented from rotating by the second stopper, so that when the heat insulating cover is closed, it can be reliably set in the closed position.

Furthermore, in the present invention, since the fulcrum of the rotatable heat insulating cover and the peeling claw are located on opposite sides of the line connecting the axes of the heating roller and the pressure roller, the fulcrum of the heat insulating cover and the peeling claw are The support shafts will be separated from each other by a large distance. If you leave this,
When the heat insulating cover is closed, it may be difficult for the tip of the peeling claw to be correctly positioned on the surface of the heating roller, but in the present invention, when the heat insulating cover is rotated to the closed position, the tip of the peeling claw and the surface of the heating roller In order to regulate the relative position of the peeling claw, a member for positioning the support shaft of the peeling claw is provided, so that the tip of the peeling claw can be correctly positioned with respect to the surface of the heating roller. Acceleration of roller wear can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing only a part of an electronic copying machine equipped with a fixing device according to the present invention, and FIG. 2 is a partial sectional view showing the state of each element when removing jammed recording paper. 3 is a partial sectional view similar to FIG. 1 showing another embodiment, and FIG. 4 is a partial sectional view showing a state similar to FIG. 2 in the embodiment shown in FIG. 3. 2... Recording paper, 4... Fixing device, 6... Heating roller, 7... Pressure roller, 9... Peeling claw, 9a...
... Tip, 22 ... Heat insulation cover, 52 ... First stopper, 61 ... Support shaft, 64 ... Positioning member, 65 ... Second stopper.

Claims (1)

[Scope of Claims] 1. A recording paper bearing a toner image is passed between a heating roller and a pressure roller that are in rolling contact with each other in a pair to fix the toner image on the recording paper. When the recording paper passes between the pressure roller and sticks to the heating roller,
A fixing device that peels the attached recording paper from the heating roller by at least one peeling claw whose tip is in contact with the surface of the heating roller, and covers at least a part of the periphery of the heating roller with a heat insulating cover. At least a part of the heat insulating cover is supported rotatably around a fulcrum located on the opposite side of the peeling claw with respect to a line connecting the axes of the heating roller and the pressure roller, and the cover is supported by the peeling claw. A first stopper is provided to stop the peeling claw at the maximum open position where the tip of the peeling nail is not exposed outside the heat insulating cover, and the peeling claw is rotatably supported via a support shaft on a rotatable heat insulating cover portion, and the tip of the peeling claw is rotatably supported via a support shaft. is provided with a biasing means for biasing the peeling claw in a direction in which the peeling claw contacts the heating roller, and a second stopper for regulating the rotation range of the peeling claw, and when the heat insulating cover is rotated to a closed position. 2. A fixing device, further comprising a member for positioning the support shaft in order to regulate the relative position between the tip of the peeling claw and the surface of the heating roller.