JP2001100576A - Device for preventing fixing unit from falling off - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve safety by preventing a fixing unit from falling off from a device body due to user's careless operation. SOLUTION: The user cannot release holding of a fixing unit 5 in a device body until a fixing unit fixing lever 12 is depressed and a fixing unit fixing knob 21 is turned, and the fixing unit 5 can be taken out in the release 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 installed in a facsimile apparatus, a copying machine, a printer, and an electrophotographic apparatus mounted on a multifunction machine thereof for fixing a toner image transferred to a sheet. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for holding a unit in an apparatus main body, and more particularly to a fixing unit falling prevention apparatus for preventing a fixing unit from being accidentally dropped from an apparatus main body.

[0002]

2. Description of the Related Art FIG. 10 is a block diagram of a printer for explaining a fixing method of a conventional fixing unit in an apparatus main body, wherein 1 is an apparatus main body, 2 is a paper feed cassette in which recording paper P is stacked and stored, Reference numeral 5 denotes an electrophotographic apparatus having a photosensitive member 4 as a main constituent member, and 5 denotes a heating roller 6 which heats and presses the recording paper P on which the toner image has been transferred in the electrophotographic apparatus 3 to fix the image. A fixing unit including a roller 7; a conveyance path 8 for the recording sheet P; a discharge roller 9 for discharging the recording sheet P after the fixing process to a discharge tray unit 10;
Reference numeral 1 denotes a cover body that covers the front side (the right side in FIG. 10) of the transport path 8 and the fixing unit 5 so as to be openable and closable.

The fixing unit 5 is detachably installed in the apparatus main body 1 so that the fixing unit 5 can be detached and attached at the time of replacement or the like. A fixing unit fixing lever 12 that is pressed down when the fixing unit 5 is taken out to release the holding of the fixing unit 5 in the apparatus main body 1, a heating roller 6 in the fixing unit 5, A pressure release lever 13 that is pressed down to remove trouble paper such as the recording paper P that has jammed in the nip with the pressure roller 7 and releases the pressure of the pressure roller 7 is provided side by side.

The cover body 11 opens the inside of the apparatus main body 1 when the fixing unit 5 is replaced or when trouble paper generated in the conveyance path 8 and the fixing unit 5 is removed. Lever 1
The lower part is supported by a shaft 14 so as to be rotatable with respect to the apparatus main body 1 so as to close the front side of the transport path 8 and the fixing unit 5 together with the pressure release lever 13 and the outside.

When replacing the fixing unit 5, the user first opens the cover body 11 to open the front side of the apparatus main body 1, depresses the fixing unit fixing lever 12, and moves the fixing unit 5 to the apparatus main body 1. Pull out from the front side of. To remove trouble paper in the nip between the heating roller 6 and the pressure roller 7 of the fixing unit 5, the user opens the cover body 11 and removes
Is opened, and the pressure release lever 13 is pressed down to release the pressure of the pressure roller 7 so that the trouble paper in the nip portion can be easily taken out.

[0006]

However, in the above-mentioned conventional technique, trouble paper in the nip between the fixing unit fixing lever 12 operated when the fixing unit 5 is replaced and the heating roller 6 and the pressure roller 7 is eliminated. Since the pressure releasing lever 13 operated when removing is located close to the fixing unit 13 and the fixing unit fixing lever 12 and the pressure releasing lever 13 are pressing operations and are very similar to each other,
For example, when the user removes jammed paper, the user may mistakenly operate the fixing unit fixing lever 12 instead of the pressure releasing lever 13. In addition, there is a possibility that the fixing unit fixing lever 12 may be operated by touching the fixing unit fixing lever 12.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide a fixing unit drop-off prevention device with improved safety by preventing the fixing unit from dropping out of the apparatus main body by a careless operation of a user. Is to do.

[0008]

According to a first aspect of the present invention, there is provided a fixing unit for fixing a toner image transferred onto a sheet detachably mounted on an apparatus main body. In a fixing unit dropout prevention device for preventing the fixing unit from falling off from the main body, a first unit holding member for holding the fixing unit at a predetermined position in the apparatus main body and releasing the fixing unit by pressing the fixing unit; And a second unit holding member that releases the holding of the fixing unit by being rotated in the direction. When the user removes the fixing unit, the user can move the first unit. If the operation of turning the second unit holding member is not performed after the holding member is pressed down, the holding of the fixing unit cannot be released. Te, safety is improved not to state as well by operating only the first unit holding member taken out fixing unit.

According to a second aspect of the present invention, in the fixing unit falling prevention apparatus according to the first aspect, when the second unit holding member does not hold the fixing unit, the periphery of the fixing unit is covered. The second unit holding member is provided with a closing prevention portion that abuts on a cover body that is provided to be able to open and close with respect to the apparatus main body to prevent the cover body from moving to a closed state. With this configuration, even when the cover body is opened and a removal operation such as replacement of the fixing unit is performed, the cover body is not closed unless the second unit holding member is returned to the position for holding the fixing unit. It is possible to prevent the user from forgetting to return the second unit holding member.

According to a third aspect of the present invention, in the fixing unit falling prevention device according to the first aspect, after the holding of the fixing unit is released, the second unit holding unit is held at a position for holding the fixing unit in the apparatus main body. The fixing device is provided with a return unit for returning the member. With this configuration, after the fixing unit replacement operation is completed, the second unit holding member automatically returns to the position where the fixing unit is held in the apparatus main body. Therefore, it is possible to eliminate a problem caused by the user forgetting to return.

According to a fourth aspect of the present invention, there is provided an apparatus for preventing a fixing unit from being detached, which is detachably mounted on an apparatus main body and for fixing a toner image transferred to a sheet, from the apparatus main body. A first unit holding member that holds the fixing unit at a predetermined position in the apparatus main body and releases the holding of the fixing unit when pressed, and a handle provided on a part of a case of the fixing unit. A third unit holding member that is provided in the vicinity and releases the holding of the fixing unit by being moved in a predetermined direction by holding the handle. At the time of removal work, the user pushes down the first unit holding member and then moves the third unit holding member with the handle. If the fixing unit is not held, the holding of the fixing unit cannot be released. Therefore, even if only the first unit holding member is operated by mistake, the fixing unit is not taken out and the safety is improved. Since the operation is performed by holding the handle, it is possible to prevent the user from inadvertently holding or touching a high-heat portion other than the handle.

According to a fifth aspect of the present invention, in the fixing unit falling-off preventing device of the fourth aspect, after the holding of the fixing unit is released, the third unit holding unit is held at a position for holding the fixing unit in the apparatus main body. The fixing unit is provided with a return unit for returning the member. With this configuration, after the fixing unit replacement operation is completed, the third unit holding member automatically returns to the position for holding the fixing unit in the apparatus main body. Therefore, it is possible to eliminate a problem caused by the user forgetting to return.

According to a sixth aspect of the present invention, there is provided an apparatus for preventing a fixing unit from being detachably mounted on a main body of an apparatus and fixing the toner image transferred onto a sheet to the main body. A first unit holding member that holds the fixing unit at a predetermined position in the apparatus main body and releases the holding of the fixing unit when pressed, and a movement of the first unit holding member in the pressing direction. And a fourth unit holding member for blocking and canceling the blocking. With this configuration, at the time of removal work such as replacement of the fixing unit, the user can use the fourth unit holding member to perform the first unit holding member.
Until the movement of the unit holding member in the pressing direction is released, the first unit holding member cannot be pressed and the holding of the fixing unit cannot be released. Even if only one of the unit holding members is operated, the fixing unit is not taken out and the safety is improved.

According to a seventh aspect of the present invention, in the apparatus for preventing the fixing unit from falling off according to the sixth aspect, the fourth unit holding member is movable or detachable to abut the first unit holding member to prevent movement. It is a characteristic pin member.

According to an eighth aspect of the present invention, in the fixing unit falling-off preventing apparatus according to the sixth aspect, the fourth unit holding member has a portion that abuts on the first unit holding member to prevent movement. It is a member.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the following description, members corresponding to those described with reference to FIG. 10 are denoted by the same reference numerals, and detailed description is omitted.

FIG. 1 is a block diagram of a printer for explaining a first embodiment of the present invention.
The fixing unit fixing lever (first unit holding member) which is depressed when the fixing unit 5 is taken out for replacement or the like and releases the holding of the fixing unit 5 in the apparatus main body 1 is different from the configuration shown in FIG. ), A fixing unit fixing knob (second unit holding member) 21 for holding the fixing unit 5 on the apparatus main body 1 is rotatably provided on a case 22 of the fixing unit 5.

As shown in FIG. 2, the fixing unit fixing knob 21 is provided so as to be rotatable about a central axis 23 with respect to the case 22, and a knob portion 24 is provided on the front surface 21a.
Are formed, and a locking lever 25 is protruded from a part of the peripheral wall 21b. The locking lever 25 can be engaged with and disengaged from an inner portion of an engagement hole 27 formed in the fixing plate 26 of the apparatus main body 1 above the fixing unit 5.

In the configuration of the first embodiment, when removing the fixing unit 5, first, the user pushes down the fixing unit fixing lever 12 to make a part of the fixing unit 5 detachable, while FIG. As shown, the user grips the knob 24 of the fixing unit fixing knob 21 and rotates the locking lever 25 approximately 90 degrees clockwise about the central axis 23 so that the locking lever 25 and the fixing plate 26 are rotated.
Is disengaged from the engagement hole 27.

As described above, the user presses the fixing unit fixing lever 12 and presses the fixing unit fixing knob 21.
Only by performing different operations on different members at different positions, such as a rotation operation, the holding of the fixing unit 5 in the apparatus main body 1 can be released, and the fixing unit 5 can be taken out. In the first embodiment, the user can inadvertently press the fixing unit fixing lever 12 in the first embodiment,
It is possible to remove the fixing unit 5 from the state where the fixing unit 5 can be taken out, so that there is no possibility that the fixing unit 5 is dropped.

FIG. 4 is a sectional view showing a part of a front part of a main part (fixing unit holding state) of a fixing unit falling prevention device for explaining a second embodiment of the present invention,
FIG. 5 is a sectional view showing a part of a front part of a main part (fixing unit holding released state) of the fixing unit falling prevention device according to the second embodiment, and the second embodiment is a structure of the first embodiment. 6 is different from that of FIG. 6 in that a projecting pin 31 that comes into contact with a projecting rib 30 projecting from an inner wall portion of the cover body 11 is eccentrically protruded from a center axis 23 of a fixing unit fixing knob 21 as shown in FIG. This is the configuration.

As shown in FIG. 4, the projecting pin 31 holds the fixing unit 5 at a position where the locking lever 25 engages with the inside of the engaging hole 27 formed in the fixing plate 26. When the protruding rib 3 of the cover body 11 is
Since the cover body 11 does not come into contact with 0, the cover body 11 is in a position to close the front side of the apparatus main body 1 to the outside.

However, as shown in FIG. 5, the projecting pin 31 rotates the cover body 11 to open the front surface of the apparatus main body 1 and the locking lever 25 of the fixing unit fixing knob 21 engages the fixing plate member 26. At the position where the engagement with the mating hole 27 is released and when the holding of the fixing unit 5 is released, the fixing unit 5 comes into contact with the protruding rib 30 of the cover body 11 and the cover body 11 is moved to the position shown in FIG. Is provided so that it cannot be returned to the closed position shown in FIG.

That is, in the second embodiment, the cover body 11 is returned to the closed position when the locking lever 25 of the fixing unit fixing knob 21 is not properly returned to a position where the locking lever 25 is engaged with the inside of the engagement hole 27. Because the first
In addition to the effects of the embodiment, the fixing unit fixing knob 21
There is also an effect that it is possible to warn the user of forgetting to return by the closed state of the cover body 11.

In the fixing unit fixing knob 21 of the first embodiment, a return means such as a return spring for urging the locking lever 25 to a position where the locking lever 25 is engaged with the inside of the engagement hole 27 is provided. Also, it is possible to prevent the user from forgetting to return the fixing unit fixing knob 21.

FIG. 7 is a sectional view showing a front side of a main part (fixed unit holding state) in a fixing unit falling-off prevention device for explaining a third embodiment of the present invention. The fixing unit fixing knob 21 of the second embodiment, that is, the configuration of the second unit holding member is changed.

In FIG. 7, as a third unit holding member, a handle portion 36 disposed opposite to a handle 35 provided on the front side of the case 22 of the fixing unit 5 is provided.
And an L-shaped fixing unit fixing lever 38 composed of an inner portion of the engaging hole 27 of the fixing plate member 26 and a detachable locking lever portion 37, and the L-shaped fixing unit fixing lever 38 is A compression spring 39 is provided between the part 38 a and the part 22 a of the case 22 of the fixing unit 5, and urges the locking lever 37 in a direction to be engaged with the engagement hole 27.

In the second embodiment, when the fixing unit fixing knob 21 is not properly returned to the engaging position, the cover body 11 cannot be closed in a predetermined state, so that the user can understand the cause. However, in the third embodiment, after the replacement of the fixing unit 5 is completed and the fixing unit 5 is attached to a predetermined position,
6 is released, the locking lever 37 of the L-shaped fixing unit fixing lever 38 is automatically engaged with the engagement hole 27 (in the upward direction in FIG. 7) by the urging force of the compression spring 39 serving as the return means. Because of the movement, the user can be prevented from forgetting to return the L-shaped fixing unit fixing lever 38.

Further, in the third embodiment, the user presses down the L-shaped fixing unit fixing lever 38 against the urging force of the compression spring 39 so as to grip the handle 35 and the handle portion 36, and the locking lever portion. Since the operation of releasing the engagement between the engagement hole 37 and the engagement hole 27 is performed, the handle portion functions as a marker for the operation, and when the fixing unit replacement operation is performed, the user can use the relatively high temperature portion around the fixing unit 5. It is possible to eliminate the danger of having.

FIG. 8 is a sectional view showing the front side of a main part (fixing unit holding state) of a fixing unit falling prevention device for explaining a fourth embodiment of the present invention. The upper end portion 12a of the fixing unit fixing lever 12, which is a first unit holding member, which is provided on the front surface of the case 22 so as to be vertically movable is fixed to the fixing plate member 2.
In this fixing unit holding state, a large diameter of a holding screw member 40 as a fourth unit holding member which is screwed into and out of the case 22 in this fixing unit holding state. The lower end portion 12b of the fixing unit fixing lever 12 abuts the head 40a of the fixing unit 12 to prevent the fixing unit fixing lever 12 from being pushed down.

In the configuration of the fourth embodiment, when removing the fixing unit 5, first, the user rotates the holding screw member 40 using an appropriate jig to mount the head 40 a of the holding screw member 40. , Fixing unit fixing lever 1
2 is moved out of the movement area at the lower end 12b (2
The state shown by the dotted line). When the fixing unit fixing lever 12 is pressed down in this state, the upper end portion 12a of the fixing unit fixing lever 12 is disengaged from the engaging hole 27 of the fixing plate member 26, and the fixing unit 5 can be taken out.

As described above, in the fourth embodiment, at the time of removal work such as replacement of the fixing unit 5, the user needs to rotate the holding screw member 40 to move the head 40a unless the fixing unit is moved. Since the holding of the fixing unit 5 cannot be released because the fixing lever 12 cannot be pressed, even if only the fixing unit fixing lever 12 is erroneously operated, the fixing unit 5 is not taken out and the safety is prevented. It is.

As the fourth unit holding member in the fourth embodiment, the holding screw member 40 has been exemplified. However, in addition to the screw, a shaft-shaped pin member which can prevent pressing of the fixing unit fixing lever 12, It is also conceivable to provide the projecting member detachably and movably with respect to the case 22 of the fixing unit 5 or the like.

As a modification of the fourth unit holding member, an eccentric cam mechanism may be used as shown in FIG. That is, for example, a flat eccentric cam 41 is provided rotatably with respect to the case 22 of the fixing unit 5, and when the lower end portion 12 b of the fixing unit fixing lever 12 abuts on the large diameter portion 41 a of the eccentric cam 41, the fixing unit is fixed. The eccentric cam 41 rotates so that the small-diameter portion 41b of the eccentric cam 41
It is also conceivable to adopt a configuration in which the fixing unit fixing lever 12 can be pressed down when it is moved to a position with respect to the lower end portion 12b of the fixing unit fixing lever 12.

[0035]

As described above, according to the present invention,
At the time of removal work such as replacement of the fixing unit, the user must press down the first unit holding member and then perform an operation of moving another unit holding member different from the first unit holding member, unless the user operates the fixing unit. Since the holding cannot be released, even if only the first unit holding member is operated by mistake, the fixing unit is not taken out, so that there is no danger of inadvertently dropping the fixing unit, thereby preventing erroneous operation. As a result, it is possible to provide a fixing unit falling prevention device that can improve safety.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a printer for describing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a front side of a main part (fixed unit holding state) according to the first embodiment of the present invention;

FIG. 3 is a perspective view showing a front side of a main part (fixing unit holding released state) according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram showing a front side of a main part (fixing unit holding state) according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram showing a front side of a main part (fixing unit holding released state) according to a second embodiment of the present invention.

FIG. 6 is a perspective view of a fixing unit fixing knob according to a second embodiment of the present invention.

FIG. 7 is a sectional view showing a front side of a main part (fixed unit holding state) according to a third embodiment of the present invention.

FIG. 8 is a sectional view showing a front side of a main part (fixed unit holding state) according to a fourth embodiment of the present invention.

FIG. 9 is a view for explaining a modification of the fourth unit holding member according to the fourth embodiment of the present invention.

FIG. 10 is a configuration diagram of a printer for explaining a fixing method of a conventional fixing unit in an apparatus main body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Apparatus main body 3 Electrophotographic apparatus 5 Fixing unit 6 Heating roller 7 Pressure roller 11 Cover body 12 Fixing unit fixing lever 13 Pressure release lever 21 Fixing unit fixing knob 22 Fixing unit case 24 Knob part 25 Locking lever 26 Fixing plate material 27 Engaging hole 30 Projecting rib 31 Projecting pin 35 Handle 36 Handle 37 Locking lever 38 L-shaped fixing unit fixing lever 39 Compression spring 40 Holding screw member 41 Eccentric cam

Claims (8)

[Claims] An apparatus for preventing a fixing unit detachably mounted on an apparatus main body for fixing a toner image transferred to a sheet from falling off the apparatus main body, wherein the fixing unit is mounted on the apparatus main body. A first unit holding member that holds the fixing unit at a predetermined position in the main body and releases the holding of the fixing unit when pressed, and a second unit holding member that releases the holding of the fixing unit by rotating in a predetermined direction A fixing unit falling prevention device comprising: a fixing member; 2. A cover body provided to be openable and closable with respect to the apparatus main body so as to cover the periphery of the fixing unit when the second unit holding member does not hold the fixing unit. 2. The fixing unit falling-off prevention device according to claim 1, wherein a closing prevention portion is provided on the second unit holding member to prevent the cover body from being moved to a closed state in contact with the fixing unit. 3. 3. The image forming apparatus according to claim 1, further comprising a return unit configured to return the second unit holding member to a position for holding the fixing unit in the apparatus main body after releasing the holding of the fixing unit. Fixing unit fall prevention device. 4. A fixing unit detachment prevention device which is detachably mounted on an apparatus main body and which prevents a fixing unit for fixing a toner image transferred onto a sheet from falling off from the apparatus main body. A first unit holding member that holds the fixing unit at a predetermined position in the main body and releases the holding of the fixing unit by being pressed, and is provided near a handle provided on a part of a case of the fixing unit, A third unit holding member that releases the holding of the fixing unit by being moved in a predetermined direction with a handle, the fixing unit being prevented from falling off. 5. The image forming apparatus according to claim 4, further comprising a return unit that returns the third unit holding member to a position for holding the fixing unit in the apparatus main body after releasing the holding of the fixing unit. Fixing unit fall prevention device. 6. A fixing unit detachment prevention device that is detachably mounted on an apparatus main body and that prevents a fixing unit for fixing a toner image transferred onto a sheet from falling off from the apparatus main body, wherein the fixing unit is mounted on the apparatus. A first unit holding member that holds the fixing unit at a predetermined position in the main body and releases the holding of the fixing unit by being pressed, and prevents movement of the first unit holding member in the pressing direction and releases the blocking. And a fourth unit holding member for performing the fixing operation. 7. The fixing unit according to claim 6, wherein the fourth unit holding member is a movable or removable pin member that abuts on the first unit holding member to prevent movement. Fall prevention device. 8. The fixing unit according to claim 6, wherein the fourth unit holding member is an eccentric cam member having a portion that abuts on the first unit holding member to prevent movement. apparatus.