JP2007086127A - Fixing device and cleaning unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning unit which is used in an image forming apparatus or the like for forming a visible image by sticking of toner and cleans a circulating endless peripheral face with a long bandlike cloth body, wherein the cloth body is driven without being slackened and can be easily replaced and load on drive of the cloth body is suppressed smaller. <P>SOLUTION: While a cleaning web 11 wound around a feed roll 12 is taken up onto a take-up roll 13, the cleaning web 11 is pressed against the peripheral face of a heat roll 1, thereby cleaning the heat roll 1. The peripheral faces 12b and 13b of the cleaning web wound around both the rolls are brought into press-contact with each other by a spring 17. When the cleaning web 11 is taken up onto the take-up roll 13 from the feed roll 12, the peripheral face of the press-contacted cleaning web is moved in the same direction as the take-up roll 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is used in an image recording apparatus such as a printer, a copying machine, and a facsimile machine, and a fixing device that heats and presses an unfixed toner image carried on a recording medium to fix it on the recording medium, and a member to be cleaned whose surface moves. The present invention relates to a cleaning device that cleans a container.

  In the process of fixing the toner image in the image forming apparatus using powdered toner, the recording is performed after the toner image is directly electrostatically transferred onto the recording medium or after the toner image is primarily transferred to the intermediate transfer member. A method of secondarily transferring to a medium and then heating and pressing is widely used. In this heating and fixing method, a recording medium carrying an unfixed toner image is passed through a nip portion where a heating rotator having a heating source and a pressure member are pressed against each other, and the toner containing the thermoplastic resin binder is heated. It is melted and pressed onto the recording medium. Such a fixing method is most widely used because it can be fixed with low power and has a low risk of ignition due to a paper jam in the fixing unit.

The heating rotator has, for example, a hollow metal core such as aluminum and a heater provided therein, and a roll-shaped member whose surface is covered with a fluororesin in order to improve releasability. Used. As the pressure member, a roll-shaped member is often used in which an elastic layer is provided on a metal core and the surface layer is covered with a fluororesin-based tube or the like having good releasability.
The heating rotator and the pressure member may be an endless belt stretched around a plurality of roll-shaped members, an endless belt pressed against a member facing the roll or a pad from the inside in a non-stretched state, and the like. You can also.

  In the fixing process as described above, when a recording medium carrying an unfixed toner image passes through the nip portion between the heating rotator and the pressure member, a phenomenon that the toner is transferred onto the surface of the heating rotator, that is, an offset is generated. May occur. In addition, paper dust existing on the recording medium may adhere to the peripheral surface of the heating rotator and induce toner offset. The offset toner adheres to the next recording medium to be transported and causes the recording medium to become dirty or cause image defects. Alternatively, the recording medium is wound around the heating rotator due to the adhesion force of the toner, and a jam occurs. For this reason, it is desirable to quickly remove the toner and the like adhering to the heating rotator, and a cleaning device has been proposed in, for example, Patent Document 1.

  The cleaning device described in Patent Document 1 cleans the outer peripheral surface by pressing and rubbing a cloth-like cleaning web against the peripheral surface of a heated rotating body that is rotationally driven. The cleaning web is a long one wound in a roll shape. By gradually winding from the feed roll to the take-up roll, a new part where the removed toner or paper dust does not adhere is brought into contact. The peripheral surface is efficiently cleaned.

The cleaning web is taken up by rotating a take-up roll by driving a motor, sending the rotation to the rotation, and rotating the roll in a driven manner, whereby the cleaning web gradually moves. Then, the cleaning web is brought into contact with the peripheral surface of the heating rotator between the two rolls by the contact roll to remove toner and paper dust (hereinafter referred to as “toner etc.”) adhering to the peripheral surface of the heating rotator. ing. In addition, a friction roll is attached to the support shafts of the take-up roll and the delivery roll, and these peripheral surfaces are brought into contact with each other so as to move in opposite directions. As a result, a braking force is applied to the rotation of the delivery roll, and a back tension is applied to the cleaning web so that no slack of the cleaning web or extra delivery of the cleaning web occurs between the two rolls.
JP-A-9-62134

However, such a cleaning apparatus has the following problems that are desired to be improved.
When the cleaning web is replaced with a new one after use of the long cleaning web, the cleaning web is taken out from the portion facing the heating rotator while being wound around the feeding roll, the winding roll and the contact roll. Exchanged. That is, the cleaning web, the feed roll, the winding roll, and the contact roll are configured as a cleaning unit, and this cleaning unit is disconnected from the driving device that transmits the driving force to the winding roll and replaced. . At this time, the cleaning web may be adhered to the peripheral surface of the heating rotator by the toner adhering to the peripheral surface of the heating rotator. Thereby, when it is going to take out a cleaning unit, a cleaning web may be pulled out from a winding roll or a delivery roll. When the take-up roll and the delivery roll of the cleaning unit are separated from the drive device, they are generally easily rotatable, and the cleaning web attached to the heating rotator is largely pulled out from the cleaning unit.

  In the device described in Patent Document 1, the friction roll fixed to the take-up roll and the friction roll fixed to the feed roll are always rubbed with the contacted peripheral surface moving in the opposite direction. As a result, the driving load of the winding roll becomes large.

  The present invention has been made to solve the above-described problems, and it is an object of the present invention to facilitate handling when replacing the cleaning web and to reduce the load when driving the cleaning web. To do.

  In order to solve the above problems, an invention according to the present application includes a heating source, a heating rotator whose endless peripheral surface moves around, and a pressure contacted with the peripheral surface of the heating rotator, thereby generating an unfixed toner image. A pressure member that presses the recording medium to be carried against the peripheral surface of the heating rotator, and a cleaning device provided to face the heating rotator, and the cleaning device is wound in a roll shape. A long cloth-like body, a feeding roll that is wound and rotated to feed the cloth-like body, and a direction in which the feeding roll rotates when feeding the cloth-like body And a part of the cloth-like body is heated and rotated until it is drawn out from the take-up roll and taken up by the take-up roll. An abutting member that presses against the body, and A delivery peripheral surface of the cloth-like member which is wound into a roll, and the outer circumferential surface of the wound cloth-like body to the take-up roll to provide a fixing device which is pressed against one another.

In this fixing device, both the outer peripheral surface of the cloth-like body wound around the feeding roll of the cleaning device and the outer peripheral surface of the cloth-like body wound around the take-up roll are pressed against each other, Rotate in opposite directions. That is, both the circumferential surfaces pressed against each other travel in the same direction, and can be driven so that their circumferential speeds are the same. Thereby, it can prevent that sagging arises in a cloth-like body during winding around from a sending roll to a winding roll. Moreover, even if the diameter of the outer peripheral surface of the wound cloth-like body changes as the cloth-like body is wound, the peripheral speeds of both outer peripheral surfaces can be maintained at the same state, It is possible to effectively prevent sagging and avoid troubles such as a cloth-like body being wound around the heating rotator.
In addition, it is not necessary to apply a braking force to the delivery roll, and the addition of driving can be reduced.

  Furthermore, when the cloth-like body is used up and replaced with a new cloth-like body, or when the cloth-like body is taken out from the fixing device together with the take-up roll and the feeding roll for inspection or the like, a driving device is provided on the fixing device main body side. When equipped, the take-up roll and the feed roll are separated from the drive transmission path. Even when the take-up roll is released from the restraint of the driving device in this way, the outer peripheral surfaces of the cloth-like bodies wound around the take-up roll and the feed roll are in pressure contact with each other. The cloth-like body is not pulled out from the take-up roll. That is, if the cloth-like body is to be pulled out largely between the delivery roll and the take-up roll, the feed roll and the take-up roll must rotate in the same direction, and this rotation is pressed against each other. Be bound. Therefore, even when the cloth-like body adheres to the heated rotating body, which is a member to be cleaned, with the cleaned toner or the like, the cloth-like body can be easily attached and detached.

  The support shaft of the feed roll is preferably supported so as to be movable in the advancing and retreating direction in a state parallel to the support shaft of the take-up roll, and the feed roll is pressed against the take-up roll by a spring or the like. Is good.

  By pressing as described above, even if the diameter of the outer peripheral surface of the cloth-like body wound around the feeding roll or the winding roll is changed, the outer peripheral surfaces are always pressed against each other. And since the winding amount and the feeding amount of the cloth-like body can be matched, the cloth-like body is sent out excessively, or the cloth-like body once wound up on the winding roll is unwound. Can be prevented.

  It is desirable that at least one of the winding roll and the delivery roll has a crown shape in which the central portion in the axial direction has a larger diameter than the vicinity of both ends and the diameter gradually decreases toward both ends.

  By forming the winding roll or the delivery roll as described above, even if these rolls are pressed against each other by the force acting on both ends in the axial direction and the axis is bent, the diameter of the roll is at the center. Since the crown shape is enlarged, the distribution of the pressing force in the axial direction of the roll can be maintained almost constant. Therefore, the cloth-like body is fed from the feed roll to the take-up roll without causing wrinkles.

  The cleaning device used in the fixing device is not limited to cleaning the heating rotator that heats and pressurizes the toner image. In addition to this, the toner is transferred to the pressure rotator that is pressed against the heating rotator and the electrostatic latent image. Thus, the toner can be used for cleaning an image carrier on which a toner image is formed and an intermediate transfer member on which the toner image is once transferred from the image carrier. Furthermore, it can also be used for cleaning an apparatus for drying and fixing an image formed by an inkjet method or a printed image.

Similarly, when the cleaning device is used as described above, even when the diameter of the outer peripheral surface wound around the feeding roll and the winding roll is changed, the cloth-like body is fed out by the same amount as the winding amount. So that slack is not generated between the feed roll and the take-up roll.
In addition, handling is facilitated when the cloth-like body is delivered and detached as a unit in which the roll and the take-up roll are integrated.

  As described above, in the fixing device and the cleaning device according to the present invention, the outer peripheral surfaces of the cloth-like body wound around both the feeding roll for feeding the cloth-like body and the winding roll for winding are always pressed against each other. Both rolls are driven to rotate in the opposite direction, so that the feed amount and the take-up amount are always the same even if the diameter of the outer peripheral surface of the cloth-like body changes as the use of the cloth-like body proceeds. Thus, extra delivery can be prevented. In addition, it is easy to handle when exchanging or removing the cloth-like body for inspection.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic sectional view showing a fixing device according to an embodiment of the present invention.
The fixing device 10 includes a heating roll 1 (heating rotator) supported so as to be rotatable around a central axis, and a pressure roll 2 (pressure rotator) rotating in pressure contact with the heating roll 1. The main part is composed of the cleaning device 5 in contact with the peripheral surface of the heating roll 1.

  The heating roll 1 is composed of a metal cylindrical cored bar 1a having conductivity and a surface release layer 1b laminated on the cylindrical cored bar 1a, and is supported by the main body frame of the image forming apparatus. And is rotationally driven. Further, a halogen heater 1c is disposed inside the heating roll 1, and heat necessary for fixing is supplied.

  The cylindrical cored bar 1a of the heating roll 1 can be made of metal such as aluminum, iron, and stainless steel having excellent thermal conductivity and rigidity. In this embodiment, aluminum is used as the core metal, and the surface release layer 1b having a thickness of 30 μm is provided. The surface release layer 1b is formed by coating a PTFE resin in which silicon carbide powder is dispersed on the peripheral surface of the cored bar and then baking it. And the outer diameter is 65 mm.

  The pressure roll 2 is made of a metal cylindrical cored bar 2a, an elastic layer 2b such as sponge or rubber formed on the surface of the cored bar, and a fluororesin provided so as to cover the surface. It is comprised with the mold release layer 2c. In this embodiment, a silicone rubber having a thickness of 12 mm is used as an elastic layer, a PFA resin tube having a thickness of 30 μm and made conductive by dispersing carbon powder is used as a release layer.

A cleaning device 5 is disposed at a position facing the peripheral surface of the heating roll 1.
As shown in FIG. 2, the cleaning device 5 includes a long cleaning web 11, a cleaning roll 11 that is wound in a roll shape, a feed roll 12 that feeds the cleaning web 11, and a winding that winds up the cleaning web 11. A roll 13, a contact roll 14 for bringing the cleaning web 11 into contact with the peripheral surface of the heating roll 1, and a driving device 15 for driving the winding roll 13 are provided. The delivery roll 12, the take-up roll 13 and the contact roll 14 (contact member) are integrated into the cleaning unit, and the cleaning unit 11 and the main body of the fixing device 10 are attached and detached as the cleaning unit. Is possible. The driving device 15 of the take-up roll 13 is supported on the fixing device main body side, and the transmission path of the driving force is joined or disconnected as the cleaning unit is attached or detached. Accordingly, a new cleaning web 11 can be supplied by replacing the cleaning unit.

  The cleaning web 11 is a long band-like member obtained by impregnating a mixed non-woven fabric of polyimide amide fibers and polyester fibers with silicone oil, and has a thickness of about 50 μm. One end is wound around the feed roll 12 and gradually wound around the take-up roll 13 from the other end.

  The winding roll 13 is rotatably supported by a support shaft and is driven to rotate by a driving device 15. The winding amount of the cleaning web 11 is controlled by controlling the rotation speed of a motor provided in the driving device 15. Adjusted. On the other hand, the feed roll 12 has a crown shape in which the central portion in the axial direction is gradually thicker than both ends, is rotatably supported by the support shaft, and the cleaning web 11 is rolled on the peripheral surface. It is wound. Then, the cleaning web 11 is fed out following the rotation of the winding roll 13. The direction in which the cleaning web 11 is wound around the feeding roll 12 rotates in the opposite direction to the winding roll 13 when the feeding roll 12 sends out the cleaning web 11 following the rotation of the winding roll 13. Is set to That is, when the outer peripheral surface of the cleaning web 11 wound around the feed roll 12 and the outer peripheral surface of the cleaning web 11 wound around the take-up roll 13 face each other, these outer peripheral surfaces move in the same direction. It has become a thing. And these outer peripheral surfaces are press-contacted with each other, and the feed roll 12 is driven to rotate by the force transmitted from the press-contact portion.

The winding roll 13 rotates at a position fixed with respect to the frame 16 of the cleaning unit. When the cleaning unit is mounted at a predetermined position in the fixing device, a rotational driving force is transmitted from the driving device 15 and is rotationally driven. The bearing 12a of the delivery roll 12 is supported so as to be able to advance and retreat with respect to the take-up roll 13. One end of a spring 17 is fixed to this bearing portion, and the other end is fixed to the frame 16 of the cleaning unit. Yes. The feed roll 12 is pressed against the take-up roll 13 by the elastic repulsive force of the spring 17 and is pressed against each other with a substantially constant pressure.
The mechanism for supporting the feed roll 12 with respect to the take-up roll 13 may be provided with a guide member 18 for guiding the movement of the bearing portion as shown in FIG. 2, or as shown in FIG. The bearing 12a may be supported on the other end of the arm 19 that is rotatably supported.

Next, the operation of the fixing device 10 will be described.
The heating roll 1 is rotationally driven in the direction of arrow A shown in FIG. 1, and the pressure roll 2 rotates following the heating roll 1. Then, the recording medium P on which the unfixed toner image is transferred is conveyed to a nip portion where the heating roll 1 and the pressure roll 2 are pressed against each other. The recording medium P moves as the heating roll 1 rotates, and the toner image T on the recording medium is melted and fixed on the recording medium by the heat transfer from the heating roll 1. Thereafter, the recording medium on which the toner image is fixed is peeled off from the heating roll 1 or the pressure roll 2 by the peeling member 3 and discharged outside the apparatus while being sandwiched by a paper discharge roll (not shown).

  When the recording medium P carrying an unfixed toner image is sandwiched in the nip portion between the heating roll 1 and the pressure roll 2, a part of the toner may be transferred to the surface of the heating roll 1. Further, the paper dust adhering to the paper as the recording medium may be transferred to the heating roll 1. Such toner may contaminate the image to be fixed next, and paper dust causes toner offset, so it is removed from the surface of the heating roll 1 as follows.

  The toner or the like adhering to the surface of the heating roll 1 is conveyed by the rotation of the heating roll 1 and reaches a position facing the cleaning device 5. Since the cleaning web 11 of the cleaning device 5 is pressed against the surface of the heating roll 1 with the contact roll 14 pressed against the back side, the peripheral surface of the heating roll is rubbed and adhered to the cleaning web 11. The toner or the like that has been wiped off by the cleaning web 11 is transferred. Thereby, the heating roll 1 is maintained in a clean state by removing the toner and the like.

  On the other hand, in the cleaning device 5, the take-up roll 13 is slowly rotated by the drive device 15, and the cleaning web 11 is pulled out from the feed roll 12 at a substantially constant speed and taken up by the take-up roll 13. As a result, the portion where the toner or the like is transferred from the peripheral surface of the heating roll 1 and becomes dirty gradually moves toward the take-up roll 13, and a clean cleaning web is always rubbed against the peripheral surface of the heating roll 1. . Thereby, the heating roll 1 is efficiently cleaned.

  The operation of feeding the cleaning web 11 from the feed roll 12 includes the outer peripheral surface 13 b of the cleaning web 11 wound around the take-up roll 13 and the outer peripheral surface 12 b of the cleaning web 11 wound around the feed roll 12. Are performed in a state where they are pressed against each other. Therefore, the cleaning web 11 is sent out from the feeding roll 12 at the same speed as the winding roll 13 winds up the cleaning web 11. This state is maintained even when the diameter of the outer peripheral surfaces 12b and 13b of the cleaning web 11 wound around the feed roll 12 or the take-up roll 13 changes as the cleaning web 11 is fed out gradually. Therefore, a state in which excess cleaning web 11 is fed between the feed roll 12 and the take-up roll 13 to cause the cleaning web 11 to sag is prevented, and the contact roll 14 is wound around with a substantially constant tension. The maintained state is maintained.

  Further, the feeding roll 12 has a crown shape in which the central portion in the axial direction has a diameter gradually thicker than both ends, so that the take-up roll 12 is caused by the force that the feeding roll 12 acts on both ends of the support shaft. Even if pressed against the pressure 13, the pressure contact force between the two is substantially constant in the axial direction. Further, the generation of wrinkles that undulate in the width direction is prevented. Therefore, the cleaning web 11 is pulled out almost uniformly from the feed roll 12 in the width direction, and is pressed almost uniformly in the axial direction of the heating roll 1 by the contact roll 14.

  When the entire length of the cleaning web 11 is wound on the winding roll 13 by driving the cleaning web 11 as described above, it is time to replace the cleaning web 11. At this time, the cleaning unit is replaced. That is, the feed roll 12, the take-up roll 13, the contact roll 14 and the cleaning web 11 wound around these are integrally removed from the main body of the fixing device 10 and replaced. At this time, the engagement of a gear or the like that transmits the driving force from the driving device 15 to the winding roll 13 is released, and the gear is disconnected from the driving force transmission path. As described above, even when the winding roll 13 is separated from the motor of the driving device 15 and the restraint from the motor is released, the cleaning web 11 that has already been wound around the winding roll 13 is pulled out. Absent. That is, the delivery roll 12 and the take-up roll 13 are in pressure contact with each other, and when the cleaning web is pulled out, both of them rotate in the same direction or only one, but this rotation is constrained to each other.

The above effects are particularly effective in the following cases.
The cleaning web 11 that is pressed against the peripheral surface of the heating roll 1 by the contact roll 14 may adhere to the peripheral surface due to the adhesiveness of the toner that was on the peripheral surface of the heating roll 1. When the cleaning unit is removed in this state, the cleaning web 11 that has already been taken up by the take-up roll 13 is subjected to a force to be pulled out by being attached to the heating roll 1. However, in the apparatus according to the present invention, the outer peripheral surfaces 12c and 13c of the cleaning web 11 wound around the feed roll 12 and the take-up roll 13 are always pressed against each other with a constant pressure. Thus, the cleaning web 11 is prevented from being largely pulled out from the cleaning unit.

  In the fixing device 10 or the cleaning device described above, an appropriate voltage can be applied using a contact roll made of a conductive material. As a result, an electric field is formed between the heating roll 1 and the contact roll 14, and the negatively charged toner or the positively charged paper powder is electrostatically attracted to the cleaning web 11 to improve the cleaning effect. You can also.

In the above-described embodiment, the cleaning web 11 is brought into contact with one place on the peripheral surface of the heating roll 1, and the toner and the like adhering to the peripheral surface of the heating roll 1 is removed at this contacted position. You may set so that it may contact | abut in a position.
Further, in the present embodiment, the feed roll 12 has a crown shape, but the winding roll 13 can also have a crown shape. Furthermore, both the delivery roll 12 and the take-up roll 13 may have a crown shape.

1 is a schematic cross-sectional view illustrating a fixing device according to an embodiment of the present invention. It is a schematic sectional drawing of the cleaning apparatus used with the fixing device shown in FIG. FIG. 6 is a schematic cross-sectional view showing another example of a cleaning device that can be used in the fixing device shown in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Heating roll, 1a: Cylindrical core metal, 1b: Surface release layer, 1c: Halogen heater, 2: Pressurizing roll, 2a: Cylindrical core metal, 2b: Elastic layer, 2c: Surface release layer, 3 : Peeling member, 5: cleaning device, 10: fixing device, 11: cleaning web, 12: delivery roll, 12a: bearing of delivery roll, 12b: outer peripheral surface of the cleaning web wound around the delivery roll, 13 : Winding roll, 13b: outer peripheral surface of the cleaning web wound around the winding roll, 14: contact roll, 15: driving device, 16: frame of cleaning device, 17: spring, 18: guide member, 19 :arm

Claims (4)

A heating rotator with a built-in heating source and an endless peripheral surface moving around,
A pressure member that is pressed against the peripheral surface of the heating rotator and presses a recording medium carrying an unfixed toner image against the peripheral surface of the heating rotator;
A cleaning device provided to face the heating rotator,
The cleaning device includes:
A long cloth-like body wound in a roll,
This cloth-like body is wound, and a feed roll for feeding out the cloth-like body by rotating;
A winding roll that is rotationally driven in a direction opposite to the direction of rotation when the feeding roll sends out the cloth-like body, and winds up the cloth-like body;
An abutting member that pulls out from the feed roll and presses a part of the cloth-like body against the heating rotator until it is taken up by the take-up roll;
A fixing device, wherein an outer peripheral surface of a cloth-like body wound around the feeding roll and an outer peripheral surface of the cloth-like body wound around the take-up roll are pressed against each other. The support shaft of the feed roll is supported so as to be movable in a forward and backward direction in a state parallel to the support shaft of the winding roll,
The fixing device according to claim 1, further comprising a pressing unit that presses the support shaft of the feed roll toward the support shaft of the winding roll.   At least one of the winding roll and the delivery roll has a crown shape in which a central portion in the axial direction has a larger diameter than the vicinity of both ends, and the diameter gradually decreases toward both ends. The fixing device according to claim 1 or 2. A cleaning device that is pressed against a member to be cleaned whose surface moves and removes surface deposits on the member to be cleaned,
A long cloth-like body wound in a roll,
This cloth-like body is wound, and a feed roll for feeding out the cloth-like body by rotating;
A winding roll that is rotationally driven in a direction opposite to the direction of rotation when the feeding roll sends out the cloth-like body, and winds up the cloth-like body;
An abutting member that is pulled out from the delivery roll and presses a part of the cloth-like body against the member to be cleaned before being taken up by the take-up roll;
A cleaning apparatus, wherein an outer peripheral surface of a cloth-like body wound around the feeding roll and an outer peripheral surface of the cloth-like body wound around the take-up roll are in pressure contact with each other.

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