JPH06250561A - Pressurizing force switching device for fixing device - Google Patents

Abstract

PURPOSE:To provide a pressurizing force switching device for fixing device capable of surely bringing a pressure-released pressurizing roller into the pressurized state when a user starts the use. CONSTITUTION:A packing material 1 for blocking a carrying passage EP of recording material is arranged on the paper discharge side of a fixing device in such a manner as to be removable, a pressure release lever 2a is protruded from notch parts 1a, 1b, and its top end part is curved. The notch parts 1a, 1b are formed to have a size and form such that the packing material 1 can be removed when the pressure release lever 2a is moved in the direction of arrow D to bring the roller pair of the fixing device into the pressurized state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an electrophotographic apparatus for fixing an image on a recording material.

[0002]

2. Description of the Related Art In a conventional fixing device, as shown in FIGS. 13 and 14, a pressure roller 6 is pressed against a fixing roller 3 by a pressing means such as a pressure spring 5 to form a nip of a predetermined width W. ing. Here, since an elastic member such as silicone rubber is generally used for the pressure roller 6, if the same portion is left under pressure for a long time, the elasticity of the portion is lost and the portion remains dented. It will not return to its original state. Therefore, generally, at the time of factory shipment, a spacer or the like is sandwiched between the shafts of the fixing roller 3 and the pressure roller 6, and the package is packed in a state in which the pressing force is released. When the user unpacks, the spacer or the like is removed to reduce the pressure. A configuration is used in which it is put on and then started to be used. However, since there is a problem in the treatment of the removed spacer in such a configuration,
A fixing device that includes a mechanical pressure releasing mechanism inside the fixing device and can release the pressure has been proposed. A specific example is shown in FIG.
And FIG. 14 will be described.

The fixing device shown in FIGS. 13 and 14 is generally used in a printer or a copying machine using an electrophotographic process, and the fixing roller 3 is mounted on a fixed bearing 4 for axially supporting the fixing roller 3. A pressure release lever 2 for reducing or releasing the pressure applied to the nip portion formed by the pressure roller 6 and the pressure roller 6 is rotatably attached. The pressure roller 6 is replaced with the fixing roller 3
The pressure spring 5 for press-contacting the shaft is the shaft portion 6a of the pressure roller 6.
Is contracted between the bearing 7 supporting the spring and the spring seat member 11. The bearing 7 is movably fitted to a guide surface parallel to a line connecting the centers of the fixing roller 3 and the pressure roller 6, or is supported by an arm end that forms an arc along substantially the same line. In this apparatus, the pressure release lever 2 is arranged at both ends of the fixing roller 3 so as to be rotatable concentrically with the fixing roller 3 in a first position (state of FIG. 13) and a second position (state of FIG. 14). ) Is rotatable. The cam follower portion 7 a of the bearing 7 is provided on the outer periphery of the base of the rotation center of the pressure release lever 2.
Is pressed to move the bearing 7 away from the fixing roller 3 against the pressing spring 5, so that the fixing roller 3 is pressed from the fixing roller 3.
There is provided a cam portion 2b that keeps away from.

At the time of factory assembly, the pressure release lever 2 is rotated to the first position in FIG. 13 to release the pressure between the fixing roller 3 and the pressure roller 6, and the product is shipped for a long time. We try to avoid applying pressure to certain parts. On the other hand, the user rotates the pressure release lever at the start of use (see FIG. 14).
Start to use). The method for the user to apply the pressure is displayed near the fixing device or described in the instruction manual or the like.

[0005]

However, according to the above-mentioned conventional example, the fixing device itself is incorporated in the inside of the main body of the device, or the pressure releasing lever itself is arranged in an inconspicuous position. In some cases, the person forgets to apply pressure when starting use.

[0006] If the user starts the application with the pressing force released at the beginning of use, the toner may be conveyed and discharged without sufficiently fixing the toner on the recording material. Not only the unfixed toner stains the inside and outside of the main body centering on the fixing device, but there are many cases in which it is misunderstood as a failure without understanding the cause.

Further, the user may pass the paper without noticing it and continue printing without being able to extract the original high-definition image.

The present invention solves the above-mentioned problems and provides a pressing force switching device of a fixing device which allows a user to surely put a pressure roller whose pressure has been released into a pressurized state at the start of use. Is intended.

[0009]

According to the present invention, the above object is to provide a pair of rollers for nipping and conveying a recording material, and a pressurizing means for applying a pressing force to one of the pair of rollers to bring them into pressure contact with each other. A pressing force switching device of a fixing device having:
Pressurizing force switching that has a lever that is formed to extend downstream from the pressure contact portion of the roller pair in the recording material conveyance direction and that is rotatable between a first position where pressure is released and a second position where pressure is applied. In the apparatus, the recording material conveyance path is closed on the downstream side in the recording material conveyance direction with respect to the pressure contact portion of the roller pair, and the closing member is provided detachably, and the closing member is within the movable range of the lever. The lever is disposed so as to project from the notch, and the notch and the protrusion of the lever interfere with each other in the first position of the lever, In the second position of the, the interference is achieved by being formed.

[0010]

According to the present invention, when the user tries to remove the closing member while the pressing force is released at the start of use,
Although the lever and the notch portion interfere with each other and the closing member cannot be removed, the closing member can be removed by moving the lever to the second position where a pressing force is applied. Therefore, even if the fixing operation is performed while the pressing force is released, the conveyance path of the recording material is blocked by the blocking member and the conveyance of the recording material is blocked, so that the user is informed that the pressing force is released.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1> First, Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view in which a packaging material for instructing a pressing operation is attached to an image forming apparatus main body,
2 is a side view of the pressure releasing means in the fixing device of this embodiment, showing a state in which the pressure is released, and FIG. 3 is a side view of the pressure releasing means in the fixing device, showing a state of being pressurized, FIG. Is a perspective view of the packaging material that instructs the pressing operation of the fixing device by rotating the pressure release lever, FIGS. 5 and 6 are enlarged views of a portion showing the direction of rotation of the pressure release lever, and FIG. It is a longitudinal cross-sectional view of an apparatus.

In FIG. 1, reference numeral 1 denotes a packing material that can be attached to and detached from the fixing device of the present invention. Tilt stoppers 1e perpendicular to the closing portion 1g are provided on both sides of a closing portion 1g that closes a sheet discharging passage of the fixing device. It is provided. The blocking portion 1g is provided with notches 1a and 1b as shown in FIG. 4 corresponding to the position of the hooking portion 2a of the pressure release lever 2 of the fixing device shown in FIGS. In the vicinity of the cutouts 1a and 1b, the direction of rotation of the lever 2 when pressure is applied by the pressure release lever 2 is indicated by an arrow D. Further, in the closed portion 1g, the lever 2 is rotated in the direction of the arrow according to the drawing or the text so that the packing material 1 itself is removed for easy understanding. In the above configuration, the closing portion 1g is a non-pressurized use start preventing portion that prevents the fixing device from being used without pressurizing.

In this embodiment, the packing material 1 as shown in FIG. 4 is mounted as a member for rotating the pressure release lever 2 to promote the pressurizing operation in the vicinity of the sheet discharge passage EP of the fixing device as shown in FIG. However, as a method of mounting, the fall prevention members 1 on both sides of the packing material 1 are attached to the inner wall 13 of the opening that constitutes the paper discharge passage EP.
The configuration may be such that e is press-fitted, or so-called snap-locking is performed on a part of the frame 8 or the like of the fixing device.

2 and 3 show an example of the pressure releasing mechanism,
At the start of use of the main body, the user rotates the hooking portion 2a of the lever 2 only once in the direction of arrow T from the first state of FIG. 2 to move it to the second position of FIG. In the enlarged view of FIG. 5, the state in which the lever 2a is rotated from the broken line state to the solid line state is shown. After turning to the second position, the hook 2a is covered by the cover member 14 as shown in FIG. 6 so that the lever 2 cannot be easily touched. That is, it is provided so as not to be confused with the fact that the user carelessly contacts the pressure release lever 2 after the start of use, or accidentally releases the pressure again to print, thereby causing a fixing failure (however, the cover is not covered). Member 14 is not shown in FIG. 5).

In the above-described structure, when printing is performed while the fixing device is depressurized, the toner is not sufficiently fixed on the recording material and is discharged, but in the present embodiment, the packing material 1 is used. The blocking portion 1g is disposed on the recording material conveying path EP so as to prevent the recording material from being conveyed, and the recording material is forcibly retained even if the recording material 1 is passed through without removing the packing material 1 while the pressure is released. , The user can be alerted and the pressing operation of the fixing device can be instructed at the same time as the removal of the packaging material. That is, as shown in the sectional view of FIG. 7, the recording material P discharged from the fixing roller 3 and the pressure roller 6 and separated by the separation guide 9.
Is blocked by the closed portion 1g of the packaging material 1 (hatched portion in FIG. 7).

Furthermore, the notches 1a, 1 of the packing material 1
As shown in FIG. 4, 1j and 1k, which are finer than 1a and 1b, respectively, are cut in the upper part of b, and the width Q of the cutout 1a, the width G of the hook 2a, and the width of the cutout 1j. The relationship of the magnitude of S is Q>G> S.

That is, the hook portion 2a of the pressure release lever 2
Since the width of the cutout portion 1a is smaller than the width G of the same, the catching portion 2a of the pressure release lever 2 is caught by the cutout portion 1j of the packing material unless it is moved to the pressurized state, that is, the second position shown in FIG. Since the material 1 cannot be removed, printing cannot be performed while the pressure is released.

In this manner, the pressure release lever 2 is rotated to bring the fixing device to the normal pressure state, and the packaging material 1 itself is prompted to be removed, and further, the sheet discharge passage closing portion 1g that prevents the sheet discharge.
By installing an adjoining device, even if printing is started with the pressure released, a malfunction will be shown to the user when one sheet of recording material is passed, and the fixing device is pressed and the packaging material 1 is removed. Can be encouraged.

In the above description, it is sufficient that the sheet discharge passage closing portion 1g is in the sheet discharge direction and can prevent the discharge of the recording material (for example, the paper P) having the minimum width usable in the image forming apparatus in which the fixing device is mounted. The portion 1g may close a part of the paper discharge passage EP.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In a normal electrophotographic apparatus, a sensor is arranged immediately after the fixing device to detect whether the recording material stays near the fixing device. FIG. 8 is a sectional view of the vicinity of the fixing device. A jam (paper jam) detection lever 10 that detects the presence or absence of the recording material P from between the separation guides 9 faces the paper discharge path. The jam detection lever 10 has a fulcrum 10
It can rotate around a. Reference numeral 15 denotes a sensor or the like, which extends from the jam detecting lever 10 shaft 10a and detects the presence or absence of a slit portion (not shown) in a portion 10b which rotates in conjunction with the jam detecting lever 10.

At the first position of the jam detecting lever 10 shown in FIG. 8, it is determined that "no recording material", and the jam detecting lever 10 is at the second position where the recording material P is normally pressed. At the position of FIG. 9, it is determined that "the recording material is present".

The front end of the recording material P pushes up the jam detecting lever 10 and rotates it to the position shown in FIG. 9, and the rear end of the recording material P passes within a certain time after the jam detecting lever 10 moves to the position shown in FIG. If it does not return to the position, it is determined that the recording material P is retained. Further, when the jam detection lever 10 is located at the position shown in FIG. 9 when the power is turned on, it is determined that the recording material P is staying, and the staying display is displayed. At this time, generally, the heater of the fixing device is not heated and remains in a cold state.

In the present embodiment, as shown in FIG. 10, the paper jam detection sensor holding portion 1c for holding the jam detection lever 10 in the operating state is provided at the closed portion of the packing material 1 in the first embodiment, so that Jam detection lever 10
9 is fixed at the position of FIG. 9, and if the user forgets to remove the pointing member and turns on the power, the recording material P is displayed as stagnant and an abnormality is detected. And the removal of the indicating member can be promoted.

That is, when the power is turned on, the abnormality is immediately recognized, the recording material is not wasted, and the heater is not heated, so that the electric power can be saved. Further, the packaging material 1 is made of heat-resistant or difficult material. Material costs can also be reduced because it is not necessary to use.

In this embodiment, the paper jam detection lever holding portion is used as a non-pressurized use start prevention portion for preventing the fixing device from being used without pressure. However, in the case where a blocking portion is also provided, Even if the packing material 1 is attached without holding the paper jam detection lever in the paper jam detection lever holding portion, the fixing device can be prevented from being used without pressure.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIGS. 11 and 12. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, an example is shown in which the pressure is released only on one side. As shown in FIG. 11, the pressure release lever is also arranged only on one side, and the packing material is provided only on the side corresponding to the pressure release lever.

On the other hand, the recording material P that has passed through the fixing device is conveyed through a paper discharge conveying path constituted by conveying means such as rollers until it is stacked on the stacking table. The carrying roller is driven by a belt, a gear, etc., and for example, a configuration as shown in FIG. 12 is an example. A gear (not shown) integrated with the fixing roller transmits the gear 15, the gear 16, and the gear 17, and the belt 19 meshed with a pulley integrated with the gear 17 drives a roller (not shown) for conveying the discharged paper. Is transmitted. The gear 16 has the same fulcrum as the gear 17. A lever 21 is rotatably attached to one end of a lever 21 rotatable about the shaft 18, and a spring 20 is attached to the other end of the lever 21 so as to urge it in the arrow Y direction. This spring 20
Thus, the gear 16 is always meshed with the gear 15, and the user pushes down the vicinity of the portion 21a of the lever 21 in the direction opposite to the arrow Y, so that the gear 16 and the gear 15 are disengaged.

In this embodiment, the 1d portion of the packing material 1 is attached to the gear 15
And the gear 16 into the gap, and the drive is cut off. And
When the user prints without removing the packing material 1, the recording material P is not ejected, so that the user is warned.

The user who notices the malfunction operates the pressure release lever 2
Is rotated in the direction of arrow T, and then the packing material 1 is removed,
The restoring force of the spring 20 causes the gear 16 to mesh with the gear 15, and the driving force is transmitted to the discharge conveyance roller.

With this structure, the packing material 1 which is a member to be discarded can be greatly reduced, and pressure can be reliably applied.
By extending the shaded portion 1f of the packing material 1 to the paper discharge conveyance roller, the user can be more surely prompted to remove the packing material 1.

[0034]

As described above, according to the present invention, unless the closing member for closing the conveying path of the recording material is provided and the lever of the pressurizing force switching device is rotated to the second position in the pressurized state, Since the closing member cannot be removed, it is possible to prevent the roller pair from being used with the pressure applied thereto being released.

[Brief description of drawings]

FIG. 1 is a diagram in which a closing member according to a first exemplary embodiment of the present invention is attached to a fixing device main body.

FIG. 2 is a side view of the pressing force switching device of the fixing device according to the first exemplary embodiment of the present invention, in which the pressing force is released.

FIG. 3 is a side view of the pressing force switching device of the fixing device according to the first exemplary embodiment of the present invention, in which a pressing force is applied.

FIG. 4 is a perspective view of a closing member according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing the relationship between the notch of the closing member and the lever of the pressing force switching device according to the first embodiment of the present invention.

6 is a perspective view showing a cover member provided around the cutout portion of FIG. 5;

FIG. 7 is a diagram illustrating a state of the recording material when the fixing operation is performed without removing the closing member according to the first exemplary embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a fixing device and a recording material presence / absence detecting device according to a second exemplary embodiment of the present invention.

FIG. 9 is a diagram illustrating a recording material presence / absence detection device of FIG. 8 and a second embodiment of the present invention.
It is a figure which shows the relationship of the closure member in.

FIG. 10 is a perspective view showing the closing member of FIG.

FIG. 11 is a diagram in which the closing member according to the third exemplary embodiment of the present invention is attached to the fixing device main body.

FIG. 12 is a diagram illustrating a relationship between a closing member and a drive system of a fixing device according to a third exemplary embodiment of the present invention.

FIG. 13 is a side view of a pressing force switching device of a fixing device in a conventional example, and is a view in a state where the pressing force is released.

FIG. 14 is a side view of a pressing force switching device of a fixing device in a conventional example, and is a view of a state in which a pressing force is applied.

[Explanation of symbols]

 1 Packing Material (Cloating Member) 1a Cutout 1c Cutout 2 Pressure Release Lever (Lever) 3 Fixing Roller 5 Pressure Spring (Pressure Means) 6 Pressure Roller

Claims (1)

[Claims] 1. A pressurizing force switching device for a fixing device, comprising: a pair of rollers for nipping and conveying a recording material; and a pressurizing means for applying a pressurizing force to one of the roller pairs to bring them into pressure contact with each other. A first position that is formed to extend downstream from the pressure contact portion of the roller pair in the recording material conveyance direction, and release the pressure;
In a pressurizing force switching device having a rotatable lever in a pressurized second position, the recording material conveyance path is closed downstream of the pressure contact portion of the roller pair in the recording material conveyance direction, and is removably arranged. The closing member is provided, the closing member includes a cutout portion having a length corresponding to a movable range of the lever, and the lever is arranged so as to project from the cutout portion. And a protruding portion of the lever, which interferes with each other at a first position of the lever and is released at a second position of the lever.