JP2008065042A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a configuration in which the front end of a separation member can react to the variations on the surface of a fixing rotating member of a nip section, even if the member of a separation portion is configured to be contactable and separable or openable and closable, or even if the member is configured depressurizable, for the longer lifetime of the fixing rotary member. <P>SOLUTION: The separation member 10 is formed with curvature sections 10b, at both the ends of the front end 10a of a recording medium non-passing area of the separation member 10, where the recording medium of a maximum size will not pass through, so that the curvature center of the curvature sections 10b and the front end 10a of the separation member 10 are related positionally as to approximately align in the axial direction. Even if the front end 10a of the separation member 10 is energized to the opposite to-be-installed fixing belt direction by this constitution, the curvature sections 10b of the recording medium non-passing area will eventually come into contact with the fixing belt, and the front end 10a of the separation member 10 and the fixing belt can maintain a non-contact state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fixing device that performs a fixing process on a recording medium holding an unfixed toner image, and an image forming apparatus equipped with the fixing device.

  2. Description of the Related Art An electrophotographic image forming apparatus that transfers toner onto a recording medium such as transfer paper for forming a visible image is provided with a fixing device for fixing the toner image on the recording medium. The fixing device includes a heated and rotating fixing roller or fixing belt, and a pressure roller or pressure belt that rotates in pressure contact with the fixing roller or fixing belt. When the recording medium passes through the nip formed by the belt, the toner on the recording medium is melted and the toner image is fixed on the recording medium.

  Toner mainly composed of resin melts at the nip and adheres to the fixing roller or fixing belt. Therefore, a wax component is added to the toner, or the surface of the fixing roller or fixing belt is released. Prevents sticking of the fixing roller or fixing belt to the toner using various means, such as coating with a protective material or applying a release agent such as silicone oil to the surface of the fixing roller or fixing belt. is doing. Further, there is a configuration in which a paper separation mechanism including a separation claw is attached to the fixing roller or the fixing belt so that the paper wound around the fixing roller or the fixing belt is forcibly separated by the melted toner.

  However, in the paper separation mechanism using the separation claw, since the separation claw and the fixing rotation member such as the fixing belt or the fixing roller are in sliding contact with each other, the toner easily collects at the contact portion, and the accumulated toner is peeled off, and the recording medium Problems such as fouling occur. Further, since the separation claw and the fixing rotating member slide, a sliding mark is generated on the fixing rotating member, resulting in a decrease in the life, and further, the sliding mark is generated as an abnormal image on the recording medium. There are issues such as.

  In recent years, there has been a tendency to add a wax component to the toner and not to apply a release agent such as silicone oil to the surface of the fixing rotating member due to reasons such as poor handling properties for the releasing agent of the fixing device. For this reason, the above problem is becoming more and more remarkable.

  In order to solve the above-mentioned problem, an invention relating to a separation plate for separating transfer paper in a non-contact state with respect to the fixing rotation member in a paper passing area through which transfer paper or the like as a recording medium passes has been proposed ( Patent Document 1).

  However, in order to maintain the separation performance equal to or higher than that of the separation claw in the non-contact state with the fixing rotation member by the separation plate or the like, the gap (gap) between the separation plate tip and the fixing rotation member is made as small as possible. The gap must be managed in 1mm increments. Furthermore, the tip of the separation plate must be arranged as close as possible to the immediate vicinity of the nip.

  In order to arrange the separation plate tip in the vicinity, the position of the surface of the rotating member immediately after the nip portion where the separation plate tip is arranged, minute fluctuations during driving, and a very narrow space immediately after the nip portion. It becomes a problem.

Patent Document 2 describes a configuration in which a separation member after a fixing nip is integrally formed of a synthetic resin, and a tip position thereof is positioned with reference to a bearing of a fixing rotation member.
JP 2006-11193 A JP 2003-122171 A

  In the conventional technique, in the invention described in Patent Document 1, the gap (gap) between the leading edge of the separation plate and the fixing rotation member is managed by the abutting member. However, since the abutting member needs to have a thickness of at least 1 mm, in order to place the tip of the separation plate in the space immediately after the narrow nip portion, the contact position between the abutting member and the fixing rotation member, the tip of the separation plate, A distance of about 6 mm or less occurs between the two.

  With this configuration, it is difficult for the tip position of the separation plate to react sensitively to changes in the surface of the fixing rotating member that is close to the tip of the separating plate, and the tip of the separating plate damages the surface of the fixing rotating member. There is a problem that the gap (gap) between the front end of the plate and the surface of the rotating body cannot be narrowed below a certain value.

  The above-mentioned problem still appears remarkably in the invention described in Patent Document 2 that does not have the abutting member as described above. In the invention described in Patent Document 2, the positioning of the tip of the separation member is arranged with reference to a bearing of a rotating body that is a fixing member.

  With this arrangement, it becomes impossible to react at all to the fluctuation of the surface of the fixing rotating member immediately after the nip, and further, when the surface of the fixing rotating member is compressed, the position changes from the original surface property. It is very difficult to place the tip of the separating member immediately after the nip portion that would end up. For this reason, in order to ensure separation performance, it is difficult to make the tip of the separation member as close as possible immediately after the nip portion and to reduce the gap between the tip of the separation member and the surface of the fixing rotation member.

  Furthermore, in recent years, in order to ensure the fixability even in a small space, a sponge member such as a foamed silicon material is used as an elastic member of the fixing roller that is a fixing rotating member, and the amount of biting with the pressure roller that presses the fixing roller is increased. More and more nip widths are increasing. In the fixing device having such a configuration, the above problem appears remarkably.

  Further, in the non-contact separation means as described above, it is difficult to configure the paper conveyance path in the separation portion so as to be openable and closable in order to manage the positional relationship between the leading end of the separation member and the fixing rotation member. For this reason, when a trouble such as a paper jam such as wrapping occurs, there is a problem that it is difficult for the user to handle the paper jam.

  In recent years, fixing rollers using a sponge material such as foamed silicon have become mainstream, and the problem with respect to the lifetime has become remarkable. As a means for solving this problem, there is an apparatus provided with a pressure-reducing mechanism for releasing the pressure of the pressure roller against the fixing roller when it is not in operation, such as after a job end.

  However, the conventional non-contact separation means has a problem that it cannot cope with minute fluctuations on the surface of the fixing roller after the pressure is released by the pressure release mechanism. Specifically, when the pressure roller depressurizes, the biting of the fixing roller that has been bitten is released, and the surface state immediately after the nip portion is restored to the original surface property of the fixing roller. In the conventional non-contact separation means, it is not possible to cope with the fluctuation of the surface state immediately after the nip portion, and the surface of the separation member is damaged at the tip of the separation member or the position where the fluctuation does not affect the tip of the separation member. Must be separated from the surface of the rotating member such as a roller immediately after the nip portion, and it is difficult to ensure separation performance.

  In view of the above-described conventional problems, the present invention has a configuration in which the member of the separation portion can be contacted / separated or opened / closed so that the paper jam can be easily handled, or can be depressurized to extend the life of the fixing rotation member. However, it is an object of the present invention to provide a fixing device and an image forming apparatus having a configuration in which the tip of the non-contact separation member can react to fluctuations on the surface of the fixing rotation member in the nip portion.

  In order to achieve the above object, according to the first aspect of the present invention, a plurality of fixing rotating members that form a nip portion to which a recording medium holding an unfixed toner image is conveyed are installed opposite to each other, and the nip portion adds the fixing rotation member. In a fixing device that performs a fixing process by pressure and heating, at least one of the fixing rotating members is formed of an elastic member on the surface side, and the one fixing rotating member and the other fixing rotating member can be brought into contact with or separated from each other or are depressurized. A fixing device configured to be capable of separating a recording member extending in a rotation axis direction of the fixing rotation member in order to peel the recording medium from the one fixing rotation member downstream in the recording medium conveyance direction in the nip portion; It is provided so as to be rotatable, and the leading end portion of the separation member is held in a non-contact state with a minute gap from the one fixing rotation member in the recording medium passage region of the one fixing rotation member. Therefore, in the recording medium non-passing region, a curvature portion that contacts or slides with the one fixing rotation member is provided at both ends of the separation member, and the center of curvature of the curvature portion of the separation means is set to the fixing rotation member. It is characterized in that it substantially coincides with the tip of the separation member in the rotation axis direction, and this configuration can increase the amount of biting in both fixing rotation members, and the nip width is widened, so that a good fixing process can be performed, and In both fixing rotating members, when returning by performing contact / separation or depressurization as necessary, even if the surface property state of the fixing rotating member in the vicinity of the leading end of the separating member changes, both ends of the recording medium non-passing area Since the tip of the separation member reacts via the curvature portion, it is possible to prevent the other member from being damaged by the tip of the separation member.

  According to a second aspect of the present invention, in the fixing device of the first aspect, the radius of the curvature portion of the separation member is set to 0.6 mm or less to improve the separation performance.

  According to a third aspect of the present invention, in the fixing device according to the first or second aspect, the separation member is integrally formed of a synthetic resin having excellent heat resistance, and a part that contacts or slides with the fixing rotation member and This is characterized in that the recording medium passage area is coated with a fluororesin, and this structure improves the slidability in the contact sliding portion between the separation member and the fixing rotating member, thereby improving the life of the fixing rotating member. In addition, the toner can be prevented from sticking to the contact surface with the recording medium.

  According to a fourth aspect of the present invention, in the fixing device according to any one of the first to third aspects, the paper discharge guide unit body that can open and close the fulcrum, which is the rotation center of the separating member, with respect to the recording medium conveyance path. Provided, when the discharge guide unit body is closed, the curvature portion of the separation member is brought into contact with the surface of one fixing rotation member, and when released, the separation member is held by a stopper provided in the discharge guide unit body, With this configuration, even when a paper jam occurs in the recording medium conveyance path in the separation portion, the processing can be easily performed. In addition, when closing such as after the end of processing, the curvature portion comes into contact with the surface of the fixing rotation member before the tip of the separation member, so that the peripheral member such as the fixing rotation member is attached at the tip of the separation member. Injury can be prevented.

  According to the fifth aspect of the present invention, the toner image formed on the image carrier is transferred to a recording medium, and an unfixed toner image on the recording medium is pressurized at a nip portion formed by a plurality of fixing rotating members. 5. An image forming apparatus in which a fixing unit for performing fixing processing by heating is installed, wherein the fixing device according to any one of claims 1 to 4 is installed as the fixing unit. By mounting a fixing device that performs good fixing processing according to the above, an image forming apparatus that performs high-quality image formation is realized.

  According to the fixing device of the present invention, since at least the surface side of one fixing rotating member is formed of an elastic member, the amount of biting in both fixing rotating members can be increased, and the nip width is widened, so that excellent fixing is achieved. Even if the surface property state of the fixing rotating member near the tip of the separating member changes when both fixing rotating members can be processed and returned by performing contact and separation or depressurization as necessary, the recording medium does not pass through. Since the tip of the separation member reacts via the curved portions at both ends of the region, it is possible to prevent damage to other members such as the surface of the fixing rotation member by the tip of the separation member, and stable and reliable fixing. Processing is realized.

  In addition, according to the image forming apparatus according to the present invention, an image forming apparatus that performs high-quality image formation is realized by mounting the fixing device that performs good fixing processing according to the present invention.

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

  FIG. 1 is a schematic configuration diagram of an embodiment of a fixing device according to the present invention.

  In FIG. 1, the fixing device includes a fixing roller 2 and a heating roller 3 in a fixing belt 1, and the pressure roller 4 is pressed against the fixing roller 2 via the fixing belt 1, and a nip portion N is formed. Forming. A halogen heater 5 serving as a heat source is provided in the heating roller 3 and the pressure roller 4, and the fixing belt 1, the fixing roller 2, and the heating roller 3 are rotationally driven in a direction indicated by an arrow by a driving unit (not shown). 1, the fixing roller 2 and the heating roller 3 constitute a fixing rotating member.

  In the present fixing device, a recording medium 6 such as transfer paper carrying an unfixed toner image is conveyed from the right side of FIG. 1, and the toner image is fixed to the recording medium 6 by applying pressure and heating at a nip portion N. It is the structure to do.

  The fixing belt 1 has a structure in which a base layer made of a polyimide resin having a thickness of 90 μm is coated with a silicon rubber having a thickness of 200 μm, and a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) having a thickness of 20 μm is coated on the outermost layer. It is something that is given. The fixing belt 1 includes a fixing roller 2 having a heat-resistant elastic layer made of foamed silicon rubber having an outer diameter of 52 mm and a thickness of 10 mm, and a heating roller 3 made of an aluminum hollow cylinder having an outer diameter of 30 mm and a thickness of 1 mm. It is installed and is driven to move by the rotation of the fixing roller 2 and the heating roller 3.

  The structure of the pressure roller 4 is made of steel, a hollow core metal having a thickness of 1 mm is covered with silicon rubber having a thickness of 2 mm, and a tube made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) is used as the outermost layer. A roller having an outer diameter of 50 mm provided.

  In this embodiment, the pressure roller 4 bites into the fixing roller 2 via the fixing belt 1 by 3.5 mm, and forms a nip width of about 14 mm.

  In FIG. 1, 7a and 7b are cleaning rollers for cleaning offset toner and paper dust remaining on the surface of the fixing belt 1 or the pressure roller 4, and 8 is a cleaning roller 6b on the pressure roller 4 side. A holding roller 9 for further holding the offset toner that has been in contact with and driven to rotate and that holds the cleaned offset toner contacts the surface of the pressure roller 4 downstream of the nip portion N in the recording medium conveyance direction, thereby transferring the transfer paper. Separating claws 10 for separating 6 from the pressure roller 4 are provided on the fixing belt 1 side downstream of the nip portion N in the recording medium conveyance direction, and a separating member for separating the transfer paper 6 from the fixing belt 1. It is.

  The separation member 10 is rotatable about a rotation fulcrum 11, and the tip 10 a of the separation member 10 is urged toward the fixing belt 1 by the urging force of the torsion spring 12.

  Further, in FIG. 1, 13 is an upper guide plate that holds the separating member 10 and guides the conveyance of the recording medium 6, 14 is a guide rotation support shaft that rotatably supports the upper guide plate 13 on the apparatus body, Reference numeral 15 denotes a lower guide plate for guiding the conveyance of the recording medium 6.

  2A and 2B are views showing the configuration of the separating member, wherein FIG. 2A is an overall perspective view, FIG. 2B is a side view from the direction of arrow A in FIG. .

  The separation member 10 is integrally formed of a synthetic resin having excellent heat resistance, and PFA (tetrafluoroethylene-perfluorofluorocarbon) is formed in a portion that contacts and slides with the fixing belt 1 and / or a region through which the recording medium 6 passes. An alkyl vinyl ether copolymer) and a fluororesin such as PTFE (polytetrafluoroethylene) are coated (a chain line portion B in FIG. 2B).

  With this configuration, the slidability of the part where the separation member 10 and the fixing belt 1 as the fixing rotating member come into contact and sliding is improved, the life of the fixing belt 1 is improved, and the toner is fixed on the contact surface with the recording medium 6. Can be prevented.

  The separating member 10 has a substantially rectangular shape in which the front end portion 10a extends in the axial direction of the fixing roller 2 via the fixing belt 1 when viewed from the plane, and as shown in FIG. A shaft portion of the rotation fulcrum 11 protrudes from this portion, and a plurality of concavo-convex portions 16 for conveying and guiding the recording medium 6 are formed on the upper portion of the base portion. Further, as shown in FIGS. 2B and 2C, a curvature portion 10b is formed at both end portions of the leading end 10a in the recording medium non-passing region where the maximum size of the recording medium 6 in the separating member 10 does not pass. The curvature center of the curvature portion 10b and the distal end 10a of the separating member 10 are set so as to have a positional relationship that substantially coincides in the axial direction.

  With the above configuration, as shown in FIG. 1, even if the tip 10 a of the separation member 10 is urged by the torsion spring 12 with respect to the fixing belt 1, the curvature portion 10 b in the recording medium non-passing area in the separation member 10 is The tip 10a always comes into contact with the tip 10a, and the tip 10a of the separating member 10 and the fixing belt 1 can be kept in a non-contact state. As a result, the fixing belt 1 and the separating member 10 do not slide even in the recording medium passage region, so that there is no sliding trace as in the conventional case, and there is a problem that it occurs as an image. In addition, the fixed toner does not collect between the leading end 10 a of the separating member 10 and the fixing belt 1.

  Note that the pressure roller 4 side is the non-image surface side of the recording medium, and therefore, the occurrence of the above-mentioned problems hardly occurs, and thus the separation claw 9 is employed in this embodiment.

  Further, by adopting the above-described configuration, in this embodiment, the front end 10a of the separation member 10 can react to the fluctuation of the surface of the fixing belt 1 near the front end 10a of the separation member 10.

  FIG. 3 is an enlarged detailed view showing a nip portion (A portion) in FIG.

  In order to ensure separation performance with the separation member 10 that is not in contact with the fixing belt 1, the tip 10 a of the separation member 10 is as close as possible to the fixing belt 1 and close to the vicinity of the downstream portion of the nip portion N. There must be.

  Specifically, as shown in FIG. 3, the distance G between the downstream point of the nip portion N and the leading end 10a of the separating member 10 is determined from the transfer paper leading edge margin W of the recording medium (transfer paper) 6 defined by the machine specifications. Also, the leading end 10a of the separating member 10 must be positioned closer to the fixing belt 1 than the transfer paper carry-out direction at the nip N exit.

  In this example, the transfer paper front end margin W is 2 mm from the specifications of the image forming apparatus, and the gap r between the front end 10a of the separation member 10 and the fixing belt 1 determined by the curvature radius of the curvature portion 10b of the separation member 10 is 0. .3 mm. The distance G between the tip 10a of the separating member 10 and the nip portion N outlet is arranged to be within 1.5 mm.

  By setting in this way, the non-contact type separation member 10 can ensure separation performance equal to or higher than that of the conventional separation claw.

  FIG. 4 is an explanatory diagram of a paper jam handling operation when a paper jam occurs at the fixing portion in the present embodiment.

  4, the upper guide plate 13 is rotated to the upper side of the apparatus main body with respect to the fixing belt 1 from the state shown in FIG. 1 with respect to the fixing belt 1 around the guide rotation support shaft 14 provided in the fixing apparatus. The recording medium conveyance path is opened. At the time of opening, the separation member 10 is urged to a predetermined position and positioned by a stopper 17 provided on the upper guide plate 13. For this reason, even if a trouble such as a paper jam occurs in the fixing portion, the processing can be easily performed.

  In this case, when returning from the open state to the closed state, the curvature portion 10b of the recording medium non-passing area comes into contact with the surface of the fixing belt 1 prior to the tip 10a of the separation member 10 as described above. Further, it is possible to prevent the surface of the fixing belt 1 from being damaged by the tip 10a of the separating member 10.

  By the way, in this embodiment, the fixing roller 2 on which the separation member 10 is opposed is configured to have at least a surface made of a silicon foam member and is excellent in elasticity, and the pressure roller 4 is opposed to the fixing roller 2. The nip portion N is formed so as to bite by about 3.5 mm. For this reason, the fixing roller 2 has a problem of compression set due to elastic deterioration and a decrease in life.

  As a countermeasure, in this example, the pressure roller 4 is provided with a pressure-reducing mechanism (not shown) with respect to the fixing roller 2.

  FIG. 5 is an explanatory view of the pressure roller depressurization in this embodiment, and the pressure roller 4 is separated from the fixing roller 2 so as not to be pressed when the apparatus is not driven.

  In this case, as shown in FIG. 6A, in order to ensure separation performance with the non-contact type separation means 10, if the position of the tip 10a of the separation member 10 is arranged in the state of FIG. When the pressure roller 4 is depressurized, the surface of the fixing belt 1 is displaced by releasing the distortion of the fixing roller 2 as shown in FIG. It reaches the position of the tip 10a.

  However, even if the property state of the surface of the fixing belt 1 in the vicinity of the tip 10a of the separation member 10 changes due to the configuration of the separation member 10 of the present embodiment, the tip 10a of the separation member 10 via the curvature portion 10b of the separation member 10. Therefore, it is possible to prevent the front surface 10a of the separating member 10 from damaging the surface of the fixing belt 1 and the like.

  FIG. 7 is a schematic configuration diagram of an embodiment of an image forming apparatus equipped with the fixing device having the above configuration according to the present invention, in which 21 is an automatic document transport unit, 22 is a document reading unit, 23 is an optical writing unit, and 24 is a plurality of units. 1 is a transfer unit, 26 is a fixing unit having the structure described with reference to FIGS. 1 to 6, 27 is a paper surface reversing unit, and 28 is a paper feeding unit.

  In FIG. 7, image information is optically read by a document reading unit 22 with respect to a document transported by an automatic document transport unit 21, and an image forming unit is formed by an optical writing unit 23 based on the read image information data. The latent image is exposed to 24 photoconductors. The latent image exposed on the photoreceptor is formed and transferred onto the intermediate transfer belt by the image forming unit 24, and the unfixed toner image is transferred to the sheet conveyed from the paper supply unit 28 by the transfer unit 25. The unfixed toner image on the paper is fixed by the fixing unit 26 and then discharged out of the apparatus main body.

  Further, when forming a double-sided image, the toner image is transferred to one side, and the paper after the fixing process is reversed by the paper side reversing unit 27 and conveyed to the transfer unit 25 again, and the toner is transferred to the other side. After the image is transferred and subjected to fixing processing by the fixing unit 26, the image is discharged out of the apparatus main body.

  In this image forming apparatus, since the fixing unit having the same configuration as that of the fixing apparatus described in FIGS. 1 to 6 is used, there is no occurrence of trouble due to a separation claw as in the prior art, and paper jam processing is also performed. An image forming apparatus that is easy and has a long life and high quality image formation is realized.

  The present invention provides a separation member for performing a fixing process on a recording medium holding an unfixed toner image by applying pressure and heating at a nip portion between fixing rotating members and separating the recording medium from the fixing rotating member. The present invention is applied to a fixing device provided, and is particularly effective when applied to a fixing device in office equipment such as a laser beam printer, a digital copying machine, and a plain paper facsimile machine.

1 is a schematic configuration diagram of an embodiment of a fixing device according to the present invention. It is a figure which shows the structure of a separation member, (a) is a whole perspective view, (b) is a side view from A arrow in (a), (c) is sectional drawing which shows a tip structure Detailed view showing an enlarged nip portion (A portion) in the present embodiment Explanatory drawing about the operation at the time of paper jam processing when a paper jam occurs in the fixing part in this embodiment Explanatory drawing of the depressurization of the pressure roller in this embodiment (A) is an expanded sectional view of the principal part of the separation member in a pressurized state, (b) is an enlarged sectional view of the principal part of the separation member in a depressurized state. 1 is a schematic configuration diagram of an embodiment of an image forming apparatus equipped with a fixing device according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixing belt 2 Fixing roller 3 Heating roller 4 Pressure roller 5 Halogen heater 10 Separation member 10a Separation member tip 10b Separation member curvature portion 11 Rotation fulcrum 12 Upper guide plate 14 Guide rotation support shaft 15 Lower guide Plate 26 Fixing unit N Nip part

Claims (5)

In a fixing device in which a plurality of fixing rotation members that form a nip portion to which a recording medium holding an unfixed toner image is conveyed are opposed to each other, and pressure is applied and heated in the nip portion to perform a fixing process.
A fixing device having a configuration in which one of the fixing rotation members is formed of an elastic member at least on the surface side, and the one fixing rotation member and the other fixing rotation member can be contacted / separated or depressurized,
In order to peel the recording medium from the one fixing rotation member downstream in the recording medium conveyance direction in the nip portion, a separation member extending in the rotation axis direction of the fixing rotation member is rotatably provided, and the one fixing rotation is performed. In order to keep the tip of the separation member in a non-contact state having a minute gap from the one fixing rotation member in the recording medium passage region of the member, the one end is disposed at both ends of the separation member in the recording medium non-passage region. A curvature portion that contacts or slides with the fixing rotation member is provided, and the center of curvature of the curvature portion of the separation means is substantially coincided with the front end portion of the separation member in the rotation axis direction of the fixing rotation member. A fixing device.   The fixing device according to claim 1, wherein a radius of the curvature portion of the separating member is set to 0.6 mm or less.   The separation member is integrally formed of a synthetic resin excellent in heat resistance, and a portion that contacts or slides with the fixing rotation member and / or the recording medium passage region is coated with a fluororesin. The fixing device according to claim 1 or 2.   A fulcrum, which is the rotation center of the separation member, is provided in a discharge guide unit body that can be opened and closed with respect to the recording medium conveyance path, and the curvature portion of the separation member is fixed to the one fixing member when the discharge guide unit body is closed. The fixing device according to claim 1, wherein the fixing member is brought into contact with the surface of the rotating member, and the separating member is held by a stopper provided in the paper discharge guide unit body when the rotating member is opened.   A fixing unit that transfers a toner image formed on an image carrier onto a recording medium, and presses and heats an unfixed toner image on the recording medium at a nip formed by a plurality of fixing rotating members to perform a fixing process. An image forming apparatus in which the fixing device according to claim 1 is installed as the fixing unit.

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