JP2008185882A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device in which a lubricant is cyclically used by recovering the lubricant applied to a pressurization belt and returning the lubricant to a lubricant supply member. <P>SOLUTION: The lubricant circulation system includes a lubricant application member 371 which comes into contact with the inside of the pressurization belt 32 and applies the lubricant thereto, a lubricant adjustment member 373 which comes into contact with the inside of the pressurization belt 32 and recovers a part of the lubricant, and the lubricant supply member 372 which houses and supplies the lubricant to the lubricant application member 371. After the lubricant is applied to the pressurization belt 32 by the lubricant application member 371, the excess lubricant is recovered by the lubricant adjustment member 373 and is housed into the lubricant application member 372 and again the lubricant is supplied to the lubricant application member 371. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an unfixed toner image formed on a transfer material, mounted on an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having these functions, by a fixing member and a pressure member. The present invention relates to a fixing device that fixes an image by applying pressure and heat, and an image forming apparatus including the fixing device.

  Conventionally, a fixing device used in an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having these functions has a fixing member maintained at a predetermined temperature and an elastic layer. A heat roller fixing system that presses and heats a transfer material on which an unfixed toner image is formed is sandwiched and conveyed by a fixing nip formed by a pressure roller that is in pressure contact with the fixing member. Widely used from monochrome machines to color machines.

  The conventional heat roller fixing type fixing device is disadvantageous in terms of power saving because it is necessary to heat a fixing member having a large heat capacity when heating the toner on the transfer material. There is a problem that it takes time to warm up, and the time until warming up (warm up time) becomes long.

  In recent years, fixing belts and pressure belts have been used in the fixing device, and these belts have a low heat capacity, and a heat-controlled heater is brought into direct pressure contact with the fixing member to greatly improve heat conduction efficiency, thereby reducing power consumption. A belt-fixing type fixing device and an image forming apparatus that have achieved a quick start that requires little warm-up time have been proposed and recently used.

  In the above fixing device, since the fixing member is pressed against the heating roller by the pressing member, if the friction between the inner surface of the fixing member and the pressing member is large, the driving of the fixing member is hindered, This causes fixing misalignment and paper wrinkles.

  For this reason, in the fixing device used in the conventional image forming apparatus, the inner surface of the fixing member is lubricated in order to reduce the friction generated between the fixing member and the pressure contact member and to enable the fixing member to run smoothly. There is a configuration for supplying the agent.

  The fixing device of Patent Document 1 is provided with a lubricant-impregnated member for preventing offset inside an endless belt that forms a fixing nip portion with a fixing roller.

The fixing device disclosed in Patent Document 2 is provided with a lubricant supply means on the inner peripheral surface of an endless belt in which a recording material is held in a fixing nip portion.
JP 10-198204 A JP 2003-195664 A

  In the fixing device disclosed in Japanese Patent Application Laid-Open No. 2004-260, the amount of lubricant applied tends to decrease remarkably when the amount of lubricant applied decreases as the lubricant is applied above the lubricant adjusting member. When there is a sliding member in contact with the inner surface of the pressure belt, the friction is particularly large, the torque is increased, energy is lost, the pressure belt is worn, and the durability is lowered. Further, slippage occurs between the fixing member and the pressure belt, and image displacement occurs.

  In the fixing device of Patent Document 2, the lubricant is applied on the side or below, but the lubricant hangs down due to its own weight and the amount of oozing increases, so that the lubricant adheres to the inner peripheral surface of the endless belt. When the amount increases, especially when there are many belt support members, the amount of bleeding increases further, and it becomes difficult to ensure durability. Further, if the supply amount of the lubricant is slightly increased, there is a problem that the bleeding due to the drooping of the lubricant increases, and the bleeding starts even when the belt is stopped.

  An object of the present invention is to prevent a lubricant from leaking from the end of a pressure belt and prevent the lubricant from adhering to a recording sheet and from fouling the inside of the apparatus. Another object of the present invention is to return the collected lubricant to the lubricant supply unit so that it can be circulated and to supply the lubricant for a long time. It is another object of the present invention to prevent image displacement due to slippage between the fixing member and the pressure belt.

  Accordingly, it is an object of the present invention to provide an image forming apparatus including a fixing device that forms a high-quality image while preventing the recording paper and the inside of the apparatus from being soiled.

  The above object can be achieved by the following solutions.

  1. In a fixing device for fixing a toner image formed on a recording material by a fixing member driven and rotated by a driving source and an endless pressure belt pressed against the fixing member, the fixing device is in contact with the inner surface of the pressure belt. A lubricant applying member for applying a lubricant; a lubricant adjusting member for contacting a part of the inner surface of the pressure belt; and collecting a part of the lubricant; and containing the lubricant and supplying the lubricant to the lubricant applying member. A lubricant supply member to be supplied, and after applying the lubricant to the pressure belt by the lubricant application member, excess lubricant is recovered by the lubricant adjustment member, and the lubricant supply member And a lubricant circulation system for supplying the lubricant to the lubricant application member again.

  2. In a fixing device for fixing a toner image formed on a recording material by a fixing member that is driven to rotate and a pressure belt that rotates while being pressed against the fixing member, a lubricant is in contact with the inner surface of the pressure belt. The fixing device is characterized in that the lubricant applying member to be applied is separated from the inner surface of the pressure belt when the rotation of the pressure belt is stopped.

  3. Image forming means for forming an image on an image carrier, paper feeding means for supplying a recording medium to the image forming means, transfer means for transferring the image to the recording medium, and the recording to which the image has been transferred An image forming apparatus comprising: the fixing device according to 1 or 2 that fixes a medium.

  The fixing device and the image forming apparatus of the present invention can obtain the following effects by the configuration described above.

  1. After the lubricant is applied to the pressure belt by the lubricant application member, the excess lubricant is recovered by the lubricant adjustment member, and flows down and stored in the lubricant supply member, and the lubricant is again applied to the lubricant application member. A lubricant circulation system to be supplied was formed. In this lubricant circulation system, the lubricant is reduced by sufficiently applying the lubricant to the pressure belt by the lubricant application member and wiping off the lubricant adhering to the pressure belt more than necessary by the lubricant adjustment member. However, the lubricant adheres sufficiently to the pressure belt until the end, and the lubricant does not adhere more than necessary, reducing the consumption of the lubricant due to the seepage of the lubricant, and the durability of the pressure belt. Improves. In addition, by supplying the lubricant to the lubricant application member, it is possible to supply the lubricant stably for a long time.

  2. The lubricant application member that applies the lubricant in contact with the inner surface of the pressure belt is controlled so as to be separated from the inner surface of the pressure belt when the rotation of the pressure belt is stopped. Is prevented, and the lubricant is prevented from fouling the inside of the apparatus.

  3. An image forming apparatus including a fixing device that forms a high-quality image by preventing recording paper and the inside of the apparatus from being damaged is provided.

  Embodiments of the present invention will be described below. The description in this column does not limit the technical scope of the claims or the meaning of terms.

  FIG. 1 is a configuration diagram showing an example of an image forming apparatus according to the present invention.

  The image forming apparatus includes an image forming apparatus main body A and an image reading apparatus B.

  The image forming apparatus main body A is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, a belt-like intermediate transfer member 6, a sheet feeding and conveying unit, a fixing device 30, and the like. Become.

  An image reading device B including an automatic document feeder DF and a document image scanning exposure device SC is installed on the upper part of the image forming apparatus main body A. The document d placed on the document table of the automatic document feeder DF is transported by a transport means, and an image on one or both sides of the document is scanned and exposed by the optical system of the document image scanning exposure device SC, and is applied to the line image sensor CCD. Is read.

  A signal formed by photoelectric conversion by the line image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in an image processing unit, and then exposure means 3Y, 3M, 3C, 3K. Sent to.

  In the image forming unit 10Y that forms a yellow (Y) image, a charging unit 2Y, an exposing unit 3Y, a developing unit 4Y, and a cleaning unit 8Y are disposed around the photoreceptor 1Y. In the image forming unit 10M that forms a magenta (M) color image, a charging unit 2M, an exposure unit 3M, a developing unit 4M, and a cleaning unit 8M are arranged around the photoreceptor 1M. In the image forming unit 10C for forming a cyan (C) color image, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a cleaning unit 8C are arranged around the photoreceptor 1C. An image forming unit 10K that forms a black (K) image has a charging unit 2K, an exposure unit 3K, a developing unit 4K, and a cleaning unit 8K arranged around the photoreceptor 1K. The charging unit 2Y and the exposure unit 3Y, the charging unit 2M and the exposure unit 3M, the charging unit 2C and the exposure device 3C, and the charging unit 2K and the exposure device 3K constitute a latent image forming unit.

  The developing units 4Y, 4M, 4C, and 4K include a two-component developer composed of a toner having a small particle size of yellow (Y), magenta (M), cyan (C), and black (K) and a carrier.

  The intermediate transfer member 6 is wound around a plurality of rollers and is rotatably supported by a driving unit (not shown).

  The fixing device 30 heats and presses the toner image on the recording material P at a fixing nip portion formed between the heated fixing member (fixing roller) 31 and the pressure belt 32 to fix the toner image.

  The respective color images formed by the image forming units 10Y, 10M, 10C, and 10K are sequentially transferred (primary transfer) by the primary transfer units 7Y, 7M, 7C, and 7K onto the rotating intermediate transfer body 6 to form a color. A combined toner image is formed. The recording material P accommodated in the paper feeding cassette 20 is fed by the paper feeding means 21 and is conveyed to the secondary transfer means 7A through the paper feeding rollers 22A, 22B, 22C, 22D, the registration rollers 23, and the like. A color image is transferred onto the recording material P (secondary transfer). The recording material P to which the color image has been transferred is heated and pressurized in the fixing device 30 to fix the color toner image on the recording material P. Thereafter, the sheet is sandwiched between the sheet discharge rollers 24 and placed on the sheet discharge tray 25 outside the apparatus.

  On the other hand, after the color image is transferred to the recording material P by the secondary transfer means 7A, the residual toner is removed by the cleaning means 8A from the intermediate transfer body 6 from which the recording material P is separated by curvature.

  The image forming apparatus for forming a color image has been described above. However, an image forming apparatus for forming a monochrome image may be used, or an intermediate transfer member may or may not be used.

  Next, the main configuration of the belt nip type fixing device 30 according to the present invention will be described.

  FIG. 2 is a cross-sectional view of the belt nip type fixing device 30 according to the present invention. FIG. 3 is an enlarged cross-sectional view of the fixing roller 31 and the pressure belt 32.

  The fixing device 30 according to the present invention includes a fixing roller 31 above the sheet passing path and a pressure belt 32 below the sheet passing path.

  Through a fixing nip formed between the fixing roller 31 and the pressure belt 32, the single color toner image or the multicolor toner image on the recording material P is fixed by heating and pressing.

  The fixing roller 31 includes a halogen lamp H therein, a cylindrical metal core 31A formed of aluminum, iron, or the like, and an elastic layer 31B that covers the cylindrical metal core 31A and is made of silicone rubber having high heat resistance, Furthermore, the elastic layer 31B is covered, and the release layer 31C is made of a fluororesin such as PFA (perfluoroalkyl vinyl ether) or PTFE (polytetrafluoroethylene).

  On the outer peripheral surface of the fixing roller 31, an external heating unit 42, a cleaning unit 43, a separation claw 44, a temperature sensor (not shown), and the like are arranged.

  The pressure belt 32 includes a base formed of polyimide having a thickness of about 100 μm and a release layer 31C formed of PFA or PTFE having a thickness of about 25 μm covering the outer surface of the base. It is formed in a shape.

  The pressure belt 32 is wound around the outer periphery of the inlet roller 33 near the introduction portion of the recording material P, the outlet roller 34 near the outlet portion of the recording material P, and the support roller 35. Abut.

  The separation claw 45 abuts on the outer peripheral surface of the pressure belt 32 around which the exit roller 34 is wound, and peels the recording material P from the pressure belt 32.

  The elevating means 46 holds a pressure unit having a pressure belt 32, an entrance roller 33, an exit roller 34, a support roller 35 and the like so as to be movable up and down, and presses the pressure belt 32 and the pressing means 36 against the fixing roller 31. .

  The pressing means 36 that presses the pressure belt 32 from the inside includes a pressing pad 361, a holding member 362, a compression spring 363, and a holder 364. The pressing pad 361 presses the inner surface side of the pressure belt 32 stretched between the inlet roller 33 and the outlet roller 34 and presses the outer surface of the fixing roller 31. The pressing pad 361 is made of a heat-resistant resin, for example, silicone rubber having a hardness of about 10 ° JISA. A pressing pad 361, a holding member 362 that holds the pressing pad 361, and a compression spring 363 that biases the holding member 362 are held in a holder 364 made of heat-resistant resin.

  The surface layer at the inner end of the pressure belt 32 is covered with a fluororesin layer. By covering the surface layer with a fluororesin layer, the wettability to the lubricant is reduced and the oil film is difficult to be formed. .

  A lubricant application unit 37 is disposed on the upstream side of the pressure belt 32 in the pressure belt conveyance direction and inside the pressure belt 32. The lubricant application unit 37 includes a lubricant application member 371, a lubricant supply member 372, a lubricant adjustment member 373, support members 374 and 375, and the like.

  The lubricant adjusting member 373 is disposed between the entrance roller 33 and the support roller 35 and slides on the inner surface of the pressure belt 32 to scrape and collect excess lubricant.

  The lubricant applying member 371 and the lubricant adjusting member 373 are formed of a nonwoven fabric such as an aramid fiber, and one end of the nonwoven fabric is bent to join the end portions, and the bent portion comes into contact with the inner surface of the pressure belt 32. A lower portion of the lubricant adjusting member 373 is formed in a bag shape, and a foaming material such as felt is inserted therein to form a lubricant supply member 372. The lubricant application member 371 and the lubricant supply member 372 are impregnated with a lubricant in advance.

  The lubricant supply member 372 stores the lubricant and supplies the lubricant to the lubricant application member 371. The lubricant adjusting member 373 is disposed between the inlet roller 33 and the pressing unit 36 and slides on the inner surface of the pressure belt 32 to scrape off excess lubricant. The support members 374 and 375 are members such as stainless steel plates that hold both side surfaces of the lubricant adjusting member 373.

  These members are formed in an integrated unit. By integrating these members, the lubricant recovery path can be made compact. In addition, maintenance for unit replacement can be performed at the same time.

  The lubricant applying means 37 applies the lubricant to the pressure belt 32 by the lubricant applying member 371, collects excess lubricant by the lubricant adjusting member 373, and flows it down to the lubricant supply member 372 for storage. Then, a lubricant circulation system for supplying the lubricant to the lubricant application member 371 again is formed.

  That is, the lubricant scraped from the inner surface of the pressure belt 32 by the lubricant adjusting member 373 is absorbed by the felt or foam lubricant adjusting member 373 and descends, and the lubricant is supplied to the lubricant applying member 371. It is absorbed by the member 372 and recycled.

  When the width of the pressure belt 32 perpendicular to the recording material conveyance direction is W1, the width of the lubricant adjusting member 373 is W2, and the width of the lubricant applying member 371 is W3, these width dimensions are as follows. Set to. W1> W2> W3.

  The lubricant applied on the pressure belt 32 by the lubricant application member 371 is pressed and stretched by the entrance roller 33, and the width dimension orthogonal to the recording material conveyance direction increases. The lubricant on the pressure belt 32 is further stretched by the lubricant adjusting member 373 to remove excess lubricant, but these width dimensions are set so as not to protrude beyond the widths of both end faces of the pressure belt 32. W1, W2, and W3 are set.

  In the fixing device 30 configured as described above, the fixing roller 31 heated by the halogen lamp H and driven by driving means (not shown) rotates in the clockwise direction shown in the figure. Further, the pressing pad 361 is pressed by the compression spring 363 via the holding member 362, and the pressing pad 361 presses the pressure belt 32 against the fixing roller 31.

  Accordingly, the pressure belt 32 rotates counterclockwise as shown in the figure by the fixing roller 31 rotated by driving of the motor M1, and is pressed against the fixing roller 31 by the pressing pad 361 to be elastically deformed. A wide fixing nip portion is formed between the roller 31 and the roller 31. Unfixed toner on the conveyed recording material P is heated and pressed at the fixing nip portion to be fixed.

  The exit roller 34 rotates by driving the motor M2 to rotate the pressure belt 32. The entrance roller 33 and the support roller 35 are driven to rotate by the rotation of the pressure belt 32.

  FIG. 4 is a cross-sectional view showing another embodiment of the fixing device according to the present invention. In addition, about the code | symbol used in this drawing, the same code | symbol is attached | subjected to the part which has the same function as FIG. Further, differences from the above embodiment will be described.

  The lubricant adjusting member 373 is disposed on the upstream side in the recording material conveyance direction of the fixing nip where the fixing roller 31 and the pressure belt 32 abut. The lubricant application member 371 and the lubricant supply member 372 are arranged below the lubricant adjustment member 373.

  In the fixing device 30 for fixing the toner image formed on the recording material P by the fixing roller 31 that is driven to rotate and the pressure belt 32 that rotates while being pressed against the fixing roller 31, the inner surface of the pressure belt 32 is contacted. The lubricant applying member 371 for applying the lubricant is controlled to be separated from the inner surface of the pressure belt 32 when the rotation of the pressure belt 32 is stopped.

  In FIG. 4, in conjunction with the stoppage of rotation of the pressure belt 32, the lubricant applying member 371 is lifted by a driving means (not shown), for example, a solenoid, and the tip of the lubricant applying member 371 is moved. The state which separated from the inner surface of the pressure belt 32 is shown.

  The tip of the lubricant application member 371 is separated from the inner surface of the pressure belt 32, so that the lubricant is prevented from leaking when stopped.

  FIG. 5 is a sectional view showing still another embodiment of the fixing device according to the present invention. In addition, about the code | symbol used in this drawing, the same code | symbol is attached | subjected to the part which has the same function as FIG. Further, differences from the above embodiment will be described.

  On the upstream side of the pressing means 36 in the conveying direction of the pressure belt, a lubricant application means 37 is fixedly arranged inside the pressure belt 32. The lubricant application unit 37 includes a lubricant application member 371, a lubricant supply member 372, a lubricant adjustment member 373, support members 374 and 375, and the like.

  The lubricant application member 371 is disposed between the outlet roller 34 and the support roller 35, is in sliding contact with the inner surface of the pressure belt 32, and applies the lubricant contained in the lubricant supply member 372 to the pressure belt 32. . The lubricant adjusting member 373 is disposed on the upstream side of the pressing means 36 between the entrance roller 33 and the exit roller 34, slidably contacts the inner surface of the pressure belt 32, scrapes off excess lubricant, and is supplied to the lubricant supply member 372. Circulate.

  At the time of releasing the fixing process, after the rotation of the pressure belt is stopped, the elevating means 46 swings around the support shaft 461 and includes the pressure belt 32, the entrance roller 33, the exit roller 34, and the support roller 35. The pressure belt unit is lowered and the winding of the pressure belt 32 and the fixing roller 31 is released.

  When the elevating means 46 further lowers the pressure belt unit, the pressure contact between the inner surface of the pressure belt 32 that stretches between the outlet roller 34 and the support roller 35 and the tip of the lubricant application member 371 is released. Separate. Accordingly, the lubricant is not supplied to the pressure belt 32 in the release state of the fixing process.

  In the above embodiment of the fixing device, the fixing roller 31 is disposed as the heating rotator. However, the present invention is not limited to this, and the fixing roller 31 is rotated by being heated by a heating source instead of the fixing roller 31. The present invention can also be applied to a fixing device having a configuration in which a belt is arranged.

Configuration of an image forming apparatus according to the present invention 1 is a cross-sectional view of a belt nip type fixing device according to the present invention. The expanded sectional view of a fixing roller and a pressure belt. FIG. 6 is a cross-sectional view showing another embodiment of the fixing device according to the present invention. FIG. 6 is a cross-sectional view showing still another embodiment of the fixing device according to the present invention.

Explanation of symbols

30 Fixing device 31 Fixing member (fixing roller)
32 Pressure belt 33 Inlet roller 34 Outlet roller 35 Support roller 36 Press means 361 Press pad 37 Lubricant application means 371 Lubricant application member 372 Lubricant supply member 373 Lubricant adjustment member 374, 375 Support member 46 Elevating means 461 Support shaft A Image forming device body W1, W2, W3 Width

Claims (8)

In a fixing device for fixing a toner image formed on a recording material by a fixing member driven and rotated by a driving source and an endless pressure belt pressed against the fixing member.
A lubricant application member that applies a lubricant in contact with the inner surface of the pressure belt;
A lubricant adjusting member that contacts the inner surface of the pressure belt and collects a part of the lubricant;
A lubricant supply member that contains the lubricant and supplies the lubricant to the lubricant application member;
Have
After the lubricant is applied to the pressure belt by the lubricant application member, excess lubricant is recovered by the lubricant adjustment member, accommodated in the lubricant supply member, and again to the lubricant application member. A fixing device having a lubricant circulation system for supplying a lubricant. The lubricant adjusting member is disposed on the upstream side in the recording material conveyance direction of the fixing nip portion where the fixing member and the pressure belt contact each other, and the lubricant application member is further upstream than the lubricant adjusting member. The fixing device according to claim 1, wherein the fixing device is arranged. The pressure belt is disposed on an upstream side of the fixing nip portion, an outlet roller disposed on an outlet of the fixing nip portion, and on the downstream side of the outlet roller and upstream of the inlet roller. The lubricant adjusting member is disposed between the fixing nip portion and the entrance roller, and the lubricant application member is disposed between the support roller and the entrance roller. The fixing device according to claim 1, wherein the fixing device is provided. The lubricant application member and the lubricant supply member are disposed below the lubricant adjustment member, and the lubricant collected by the lubricant adjustment member flows down and is collected by the lubricant supply member. The fixing device according to claim 1, wherein the fixing device is one of the fixing devices. 5. The fixing device according to claim 1, wherein a width dimension of the lubricant adjusting member is made larger than a width dimension orthogonal to the recording material conveyance direction of the lubricant application member. The lubricant application member that applies a lubricant in contact with the inner surface of the pressure belt is separated from the inner surface of the pressure belt when the rotation of the pressure belt is stopped. The fixing device according to any one of 1 to 5. The fixing device according to claim 6, wherein the lubricant supply member is controlled to be separated from the inner surface of the pressure belt in conjunction with the rotation stop of the pressure belt. Image forming means for forming an image on an image carrier, paper feeding means for supplying a recording medium to the image forming means, transfer means for transferring the image to the recording medium, and the recording to which the image has been transferred An image forming apparatus comprising: the fixing device according to claim 1 for fixing a medium.

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