JP2012098451A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of accurately maintaining a fine gap between rotation bodies forming a fixing nip portion and a plurality of separation plates and to provide an image forming apparatus.SOLUTION: The fixing device includes two rotation bodies forming the fixing nip portion and a separation plate unit 6 comprising a plurality of separation plates 14 and a holding member 16 holding the plurality of separation plates 14 in such a state that they are arranged side by side in the axial direction of the rotation body and arranged so that the separation plates 14 are in a non-contact state with the rotation bodies, on the side of at least one of the two rotation bodies. The separation plates 14 are held by the holding member 16 through brackets 17 storing the separation plates 14 and the separation plate unit 6 includes a gap adjustment mechanism adjusting the distance of the fine gap between the surface of the rotation body and the top end of the separation plate 14 in a cross section perpendicular to the axial direction of the rotation body between the separation plate 14 and the bracket 17 and an inclination adjustment mechanism adjusting the inclination of the top end of the separation plate 14 with respect to the axial direction of the rotation body between the bracket 17 and the holding member 16.

Description

  The present invention relates to a fixing device and an image forming apparatus such as a laser beam printer, a digital copying machine, and a plain paper fax machine including the fixing device.

  In an image forming apparatus using toner for forming a visible image, a fixing device is provided to fix the toner image as a permanent image on a recording medium such as transfer paper. In the fixing device, a fixing nip portion which is a pressure contact portion formed by a fixing roller or a fixing belt which is heated and rotated, and a pressure roller or pressure member which is pressed and rotated by the fixing roller. As a result, the toner carried on the recording medium is melted and the toner image is fixed on the recording medium.

  Here, the toner mainly composed of resin melts at the pressure contact part 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. To prevent the toner from adhering to the fixing roller or the fixing belt 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. Yes.

  Further, a sheet separation mechanism having a separation claw is attached to the fixing roller or the fixing belt, and the recording medium to be wound around the fixing roller or the fixing belt is forcibly separated by the melted toner.

  However, since the separation means using the separation claw is in sliding contact with the separation claw and a fixing member such as a fixing belt or a fixing roller, the toner easily collects at the contact portion. Problems such as fouling occur. Further, since the separation claw and the rotating member that is the fixing member slide, when the release material is coated on the surface of the rotating member, a sliding mark is generated on the rotating member, and the life is shortened. There is a problem that the sliding trace is generated as an abnormal image on the recording medium. This problem also applies to the pressure roller and the pressure belt.

  In recent years, the release agent of the fixing device tends to eliminate the application of a release agent such as silicone oil to the surface of the rotating body as a fixing member by adding a wax component to the toner for reasons such as poor handling. Therefore, the above problems are becoming more and more prominent.

  In order to solve the above-described problems, an invention relating to a separation plate or the like that separates a recording medium that is disposed in a non-contact state in a non-contact state within a maximum image area in a non-contact state has been proposed.

  However, in order to maintain separation performance equivalent to or higher than that of the separation claw in a non-contact state with a rotating member that is a fixing member such as a separating plate, the gap between the tip of the separating portion and the rotating member that is a fixing member is as small as possible. And the gap must be maintained in units of 0.1 mm. Furthermore, it is necessary to dispose the leading end of the separation portion as close as possible immediately after the fixing nip portion.

  Here, when the tip of the separation part is arranged as close as possible to the position immediately after the fixing nip part, the position of the surface of the rotating body immediately after the fixing nip part where the separation plate tip is arranged, minute fluctuations during driving, and further the fixing nip part Since it is immediately after, it is necessary to consider a very narrow space. Also, for the purpose of preventing wrinkles of the recording medium and improving the transportability, the fixing roller, the pressure roller, etc. are rollers whose outer shape is a normal crown shape or a reverse crown shape, and the gap between such a roller and the separation plate One of the challenges is to maintain a uniform small gap in management.

  To deal with these problems, for example, Patent Document 1 describes an invention in which a gap (gap) between a separation guide tip and a rotating body is managed by an abutting member provided outside the maximum image area.

  However, in this configuration, since the separation guide is integrally formed of a heat-resistant resin, the separation guide is warped not a little, and deformation due to the influence of heat cannot be ignored. It was difficult to maintain a 1-0.6 mm gap. In particular, in recent years, for the purpose of improving fixing performance and heat insulation in downsize, the elastic layer of the fixing roller has become thicker and the use of a low-hardness roller is increasing. However, it has become difficult to suppress gap variation due to touching, bending, and thermal expansion with high accuracy.

  Similarly, Patent Document 2 describes an invention in which a gap (gap) between the front end of the separation plate and the rotating body is managed by an abutting member. However, the separation plate is a straight plate in the axial direction, and there is a limit to maintaining a gap between the local fixing roller and the fixing belt surface layer. In addition, when the fixing roller is provided with a normal crown shape, reverse crown shape, etc., if the tip of the separation plate is straight in the axial direction, there will always be a deviation in the gap between the fixing roller and the fixing belt surface layer in the axial direction. However, there was a limit to maintaining a small gap according to the shape.

  The present invention has been made in view of the above problems in the prior art, and a fixing device capable of accurately maintaining a minute gap between a rotating body forming a fixing nip portion and a plurality of separation plates, and the fixing device. An object of the present invention is to provide an image forming apparatus including a fixing device.

The present invention provided to solve the above problems is as follows. In addition, the site | part and code | symbol etc. which respond | correspond in the form for implementing this invention in a parenthesis are shown.
[1] Two rotating bodies (fixing belt 2, pressure roller 4) that form a fixing nip portion (fixing nip portion N) by pressure contact, a plurality of separation plates (separation plates 14 and 24), and the plurality of the plurality of separation plates A holding member (holding member 16) that holds the separating plate side by side in the axial direction of the rotating body, and the separating plate is not in contact with the rotating body on the rotating body side of at least one of the two rotating bodies. A separation plate unit (separation plate units 6, 6 ′, 6 ″) arranged so that the separation plate unit has a cross section perpendicular to the axial direction of the rotating body for each of the separation plates. A gap adjusting mechanism for adjusting a distance of a minute gap between the surface of the rotating body and the tip of the separation plate, and an inclination adjusting mechanism for adjusting the inclination of the tip of the separating plate with respect to the axial direction of the rotating body. A fixing device (fixing device 2) 0, FIG. 1, FIG. 5 to FIG. 8, FIG. 10 to FIG.
[2] The separation plate is held by the holding member via brackets (brackets 17 and 27) for housing the separation plate, and the gap adjusting mechanism is provided between the separation plate and the bracket. The fixing device according to [1], wherein the tilt adjusting mechanism is provided between the bracket and the holding member (FIGS. 8 and 12).
[3] The inclination adjusting mechanism positions the bracket at a predetermined position in the axial direction of the rotating body in the holding member, and supports the bracket rotation so as to be rotatable with respect to the axial direction of the rotating body. Bracket tilt fixing means for fixing the bracket rotated by the bracket rotation support means (the bracket rotation boss 16b, the bracket rotation hole 17b) and the bracket rotation support means so that the tip of the separation plate is parallel to the surface of the rotating body. The fixing device according to [2] (FIG. 8), which includes a fixing screw 19, an adjustment hole 16c, and a screw hole 17c).
[4] The inclination adjusting mechanism positions the bracket at a predetermined position in the axial direction of the rotating body in the holding member, and rotates the bracket so as to be rotatable so as to be inclined with respect to the axial direction of the rotating body. Support means (bracket rotation shaft 2j, bracket rotation hole 27b) and the bracket rotation support means urging the bracket in its rotation direction while the tip of the separation plate is parallel to the surface of the rotating body. Bracket fixing means (adjustment screw 29, spring 2b, screw hole) for holding the fixing device according to [2] (FIG. 12).
[5] The gap adjusting mechanism includes a separation plate rotation support unit (a separation plate rotation shaft 14j) that rotatably supports the separation plate in a direction in which the tip of the separation plate approaches or separates from the rotating body in the bracket. , Support hole 17a, separation plate rotating shaft 24j, support hole 27a), and a small gap between the surface of the rotating body and the tip of the separation plate while urging the separation plate in the rotation direction in the separation plate rotation support means. Separating plate rotation holding means (adjustment screw 18, spring 1a, screw hole 16d, adjustment screw 28, spring 2a, screw hole 16d) for holding the separation plate at a position where is a desired distance. The fixing device according to any one of [2] to [4] (FIGS. 8 and 12).
[6] The separation plate unit is in contact with the rotating body and holds a pair of butting members (abutting members 15) that hold the tips of the plurality of separating plates in a non-contact state separated from the rotating body by a minute gap. The fixing device according to any one of [1] to [5] (FIGS. 5, 10, and 14), wherein the holding member is provided with the fixing member.
[7] In the separation plate, a hard base material (base materials 14a and 24a) and a tip portion (tip portions 14b and 24b) made of a fluororesin softer than the base material are integrally formed by insert molding. The fixing device according to any one of [1] to [6] (FIGS. 6 and 11).
[8] The separation plate unit is disposed on the downstream side of the separation plate in the recording medium conveyance direction, and has a guide member (guide members 1g and 2g) for guiding the recording medium discharged from the fixing nip portion. Further, on the recording medium conveyance path side, a part of the guide member (projections 1gt, 2gt) extends so as to enter a hole (insertion hole 14c, 24c) provided in the center of the separation plate. The fixing device according to any one of [1] to [7] (FIGS. 6, 9, 11, and 13).
[9] The fixing device according to any one of [1] to [7], wherein the separation plate has a driven roller (driven roller 2gr) on the conveyance path side of the recording medium. FIG. 15).
[10] An image forming apparatus (image forming apparatus 100, FIG. 16) comprising the fixing device (fixing device 20) according to any one of [1] to [9].

According to the fixing device of the present invention, by performing inclination adjustment and gap adjustment for each of the plurality of separation plates by the inclination adjustment mechanism and the gap adjustment mechanism, it is assumed that the target rotating body has a normal crown shape or a reverse crown shape. Since the inclination of the tip of the separation plate with respect to the rotating body surface layer parallel to the axial direction is adjusted at each location where the separation plate is arranged, and the minute gap in the cross section perpendicular to the axial direction is adjusted to the rotating body surface layer, The gap between the tip of the separation plate and the pressure roller surface layer can be adjusted accurately and uniformly throughout the separation plate unit, and the separation performance can be improved. In addition, since the position of the tip of the separation plate with respect to the rotating body is fixed in a non-contact state, it is possible to prevent the separation plate from coming into contact with the surface of the rotating body and being damaged due to the collision of the recording medium.
According to the image forming apparatus of the present invention, since the fixing device of the present invention is provided, it is possible to stably form an image without causing a jam in the fixing nip portion.

1 is a schematic diagram illustrating a configuration of a fixing device according to the present invention. FIG. 2 is a side view illustrating a configuration of a fixing device according to the present invention. FIG. 3 is a side view showing a configuration around a heating roller of a fixing device according to the present invention. FIG. 3 is a view of the periphery of the heating roller of the fixing device according to the present invention as viewed obliquely from the fixing device. It is a perspective view which shows the 1st structural example of the separation plate unit used by this invention. It is a figure which shows the structure (1) of a separation plate. It is a perspective view which shows the structure of the separation plate in the separation plate unit of FIG. 5, and its peripheral part. FIG. 8 is an exploded view related to a gap adjusting mechanism and an inclination adjusting mechanism of the separation plate shown in FIG. 7. FIG. 6 is a diagram illustrating a configuration of a separation plate in the separation plate unit of FIG. 5 and a guide member disposed on the downstream side in the recording medium conveyance direction. It is a perspective view which shows the 2nd structural example of the separation plate unit used by this invention. It is a figure which shows the structure (2) of a separation plate. It is an exploded view regarding the gap adjustment mechanism and inclination adjustment mechanism of the separation plate shown in FIG. It is a figure which shows the structure of the guide member arrange | positioned in the separation plate in the separation plate unit of FIG. 10, and its recording medium conveyance direction. FIG. 11 is a perspective view illustrating another configuration of a separation plate and a guide member disposed on the downstream side in the recording medium conveyance direction in the separation plate unit of FIG. 10. It is sectional drawing which shows the structure of the separating plate and guide member in the separating plate unit of FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to the present invention.

The configurations of the fixing device and the image forming apparatus according to the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration of a fixing device according to the present invention.
As shown in FIG. 1, a fixing device 20 according to the present invention includes a fixing belt 2 that is stretched over a fixing roller 1 and a heating roller 3 with a constant tension, and whose surface is heated via a heating roller 3 by a heater 3h. The pressure roller 4 that is rotatably contacted with the fixing belt 2 to form the fixing nip portion N, and the recording plate discharge side of the fixing nip portion N on the recording medium discharge side are arranged close to the fixing belt 2 for fixing. A separation plate unit 5 that prevents the recording medium from being wound around the belt 2 and a recording medium that is disposed on the recording medium discharge side of the fixing nip portion N and close to the pressure roller 4. And a separation plate unit 6 for preventing winding.

  Here, the fixing belt 2 is an endless belt having an inner diameter of 80 mm. As a cross-sectional structure, for example, a silicone rubber layer having a thickness of 200 μm is formed on a polyimide (PI) base material having a thickness of 90 μm, and the outermost layer is further formed thereon. It has a three-layer structure in which a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) layer having a thickness of 20 μm is formed by coating.

  The fixing roller 1 has a configuration including a heat-resistant / elastic layer made of silicone rubber or fluororubber having an outer diameter of 54 mm and a thickness of 15 mm. The heating roller 3 is made of an aluminum hollow cylinder having an outer diameter of 40 mm and a thickness of 1 mm or less, and includes a heater 3 h such as a halogen heater inside.

  The pressure roller 4 is made of steel and covered with a hollow core metal having a thickness of 1 mm and a silicone rubber having a thickness of 1.5 mm. The outermost layer is a roller having an outer diameter of 65 mm having a PFA tube. The heater 4h is provided. The pressure roller 4 is pressed against the fixing belt 2 by being pressed toward the fixing roller 1 with a constant pressure by a pressure mechanism 4a (not shown) to form a fixing nip portion N. In this configuration, the pressure roller 4 bites into the fixing roller 1 by 4 mm via the fixing belt 2 to form a nip width of about 16 mm.

  When the fixing device 20 is driven, the pressure roller 4 is rotated counterclockwise in the drawing by a drive mechanism (not shown) while the pressure roller 4 is pressed against the fixing belt 2, and the fixing is performed accordingly. The belt 2, the fixing roller 1, and the heating roller 3 are rotated together, and the fixing belt 2 is driven in a direction for discharging the recording medium (clockwise direction in FIG. 1). At the time of fixing, the fixing belt 2 is heated to a temperature suitable for toner fixing by a heater 3 h disposed inside the heating roller 3.

  In the present invention, the fixing belt type shown in FIG. 1 is shown as the fixing member. However, the fixing member is not limited to this, and a fixing roller type consisting of a hollow cylindrical roller (fixing roller) may be used. . In the present invention, the rotating body includes a fixing member (a fixing roller in the case of the fixing belt 2 and the fixing roller system) and a pressure member (a pressure belt in the case of the pressure roller 4 and the pressure belt system). It is.

Further, as shown in FIGS. 1 and 2, a separation plate unit 5 is provided on the discharge side of the fixing nip portion N and on the fixing belt 2 side in order to peel the recording medium from the fixing belt 2. FIG. 2 is a side view of the fixing device 20.
As shown in FIG. 2, the separation plate unit 5 is retracted from the fixing nip portion N outlet so that the recording medium can be removed when a paper jam occurs. It is the structure which can expose a part. Further, when the separation plate unit 5 is mounted at the fixing nip N outlet, the separation means rotation shaft 10 of the separation plate unit 5 is fitted into the rotation bearing groove 11 provided in the fixing side plate 20f holding the fixing roller 1 and separated. The means rotation shaft 10 can be positioned with high accuracy relative to the fixing roller 1. The separating means (separating plate and abutting member) is configured to be rotatable about the separating means rotating shaft 10, and the elastic force of the tension spring 12 is centered on the separating means rotating shaft 10 of the separating means. The abutting member of the separating means is pressed against the fixing roller 1 via the fixing belt 2 so that the leading end of the separating plate is against the fixing belt 2. Thus, they are arranged in a non-contact state with a predetermined minute gap.

1, 3, and 4, a separation plate unit 6 for separating the recording medium from the pressure roller 4 is also provided on the discharge roller side of the fixing nip portion N and on the pressure roller 4 side. ing. 3 is a view of the fixing device 20 as viewed from the side, and FIG. 4 is a view of the fixing device 20 as viewed from obliquely above. In each figure, the upper structure including the fixing roller 1 and the like is omitted.
As shown in FIGS. 3A and 4A, the separation plate unit 6 is fixed so as to be integrated with the unit of the pressure roller 4, and is pressurized by the pressure mechanism 4a. The roller 4 moves together with the pressure roller 4 during the pressure / depressurization operation to the fixing roller 1.

  Also in the separation plate unit 6, the separation means (separation plate and abutting member) is rotatable around the separation means rotation shaft 10, and here, the elastic force of the torsion spring 13 is rotated by the separation means. By acting on the receiving member 16a provided on the separating means side with respect to the shaft 10 (FIGS. 3B, 4B and 4C), the separating means is pressurized around the separating means rotating shaft 10. The urging member rotates toward the roller 4 side, the abutting member of the separating means is pressed against the pressure roller 4, and the tip of the separation plate has a predetermined minute gap with respect to the pressure roller 4. They are arranged in a non-contact state (FIGS. 3A and 4A).

In the fixing device 20, as shown in FIG. 1, the surface of the fixing belt 2 is heated to a predetermined temperature while the fixing belt 2 and the pressure roller 4 form a fixing nip portion N and are rotationally driven. The recording medium on which the unfixed toner is formed is guided by the entrance guide plate 9 and passed through the fixing nip portion N, and the unfixed toner is thermally fused onto the recording medium by pressurization and heating in the fixing nip portion N. Fix it. Subsequently, the toner-fixed recording medium is discharged from the fixing nip portion N. At this time, the recording medium may come out while being wound around the fixing belt 2. In that case, the recording medium is separated from the fixing belt 2 by the front end of the separation plate of the separation plate unit 5 coming into contact with the leading end of the recording medium. When the recording medium comes out while being wound around the pressure roller 4, the leading end of the separation plate of the separation plate unit 6 contacts the leading end of the recording medium, so that the recording medium is removed from the pressure roller. 4 is separated.
Thereafter, the recording medium discharged from the fixing nip N is sent out from the fixing device 20 by the guidance of the relay discharge guide lower unit 7 and the discharge guide plate unit 8.

  The image forming apparatus (described later) of the present invention has a double-sided printing function. In the fixing device 20, the first surface (printed surface) is the pressure roller 4 when fixing the second surface of double-sided printing. Come into contact with. At this time, in the configuration in which the separation claw contacts the pressure roller 4 as in the conventional fixing device, the surface of the pressure roller 4 damaged by the separation claw adversely affects the image on the first surface. 4 The separation plate in the separation plate unit 6 needs to be in a non-contact state with respect to the pressure roller 4 so that the surface is not damaged.

Here, in the case of double-sided printing, the first surface (printed surface) comes into contact with the pressure roller 4 at the time of fixing the second surface and becomes easy to stick. Therefore, the separation plate in the separation plate unit 6 is a pressure roller. Therefore, it is necessary to accurately arrange the four with a predetermined minute gap amount. In particular, since the pressure roller 4 is relatively hard (at least hard enough to bite into the fixing member when forming the fixing nip portion N), the pressure roller 4 and the separation plate front end of the separation plate unit 6 are heated. The minute gap amount with the pressure roller 4 needs to be smaller than the case (for example, the minute gap amount 0.3 mm) with respect to the fixing member (fixing belt 2) (for example, the minute gap amount 0.1 mm). Further, considering the component accuracy of the separation plate unit 6, the minute gap needs to be adjusted by each of the plurality of separation plates arranged in the axial direction of the pressure roller 4.
The pressure roller 4 is not usually a roller that is flat in the axial direction, but is a roller with a reverse crown that increases in diameter toward the end in the axial direction (a pinching roller) or a roller with a normal crown (a drum). Therefore, it is difficult to accurately adjust the target minute gap amount when the tips of the plurality of separation plates arranged in the axial direction of the pressure roller 4 remain horizontal in the axial direction. there were.

  The inventor has intensively studied to solve this problem, and devised the structure of the separation plate unit, thereby achieving the present invention. Hereinafter, the configuration of the separation plate unit that forms the basis of the present invention will be described.

[Separation plate unit (first configuration example)]
First, a first configuration example of a separation plate unit applied to the fixing device according to the present invention will be described.
FIG. 5 is a perspective view showing the configuration of the separation plate unit 6, as viewed from the recording medium conveyance path side in FIG. 1. The longitudinal direction of the separation plate unit 6 is the axial direction of the pressure roller 4.

  As shown in FIG. 5, the separation plate unit 6 includes a plurality of separation plates 14 (seven separation plates 14 in FIG. 4), a pair of abutting members 15, separation means rotating shafts 10 and receiving members at both longitudinal ends. A fixing member 20 including a plurality of separation plates 14 and a pair of abutting members 15 which are arranged and held in the direction of the separation means rotating shaft 10 (longitudinal direction of the separation plate unit). In FIG. 2, the pressure roller 4 and the separating member rotating shaft 10 of the holding member 16 are arranged substantially parallel to the pressure roller 4 side. Further, the separation plate unit 6 has a guide member 1g on the recording medium conveyance path side.

  Here, the separation plate 14 is strong enough not to be deformed even when the recording medium discharged from the fixing nip N collides with it, and even if the tip contacts the pressure roller 4, the surface of the pressure roller 4 is not damaged. It preferably has a degree of flexibility and a toner releasability that prevents the toner from adhering.

  FIG. 6 is a diagram illustrating a configuration example of the separation plate 14. 6A is a perspective view of the separation plate 14, FIG. 6B is a top view of the separation plate 14, and FIG. 6C is a cross-sectional view along AA in FIG. 6B.

  As shown in FIG. 6, the separation plate 14 is made of a material harder than fluororesin and is processed by sheet metal processing so as to have a predetermined width on the tip side, and the tip of the base material 14 a is softer than the base material 14 a. And a tip portion 14b integrally formed by insert molding of fluororesin. The base material 14a may not be a sheet metal processed product, but may be a hard resin material such as PPS (polyphenylene sulfide resin) or a peak material.

  Here, the base material 14a includes a through hole 14h provided at an end opposite to the front end part 14b and a front end part 14b in the middle of the front end part 14b and the through hole 14h. A separating plate rotating shaft 14j extending in both directions corresponding to the width direction is provided. In addition, an insertion hole 14c into which a part of the guide member 1g (protrusion 1gt) is inserted is provided at the center in the width direction on the distal end portion 14b side of the base material 14a (described later).

  The tip portion 14b is made of a fluororesin having excellent heat resistance and toner releasability. In particular, by using tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) having a high releasability, it becomes more advantageous for toner accumulation and adhesion, and toner accumulation and adhesion on the surface of the tip 14b is prevented. Therefore, the toner does not rub against the image surface at the leading end portion 14b to become an abnormal image, and good image quality can be obtained. Moreover, since the resin excellent in non-aggressiveness is used for the front-end | tip part 14b, malfunctions, such as scratching a partner member, can be prevented. Furthermore, since the tip end portion 14b is excellent in slidability with the pressure roller 4, even if the tip end portion 14b contacts the pressure roller 4, the pressure roller 4 is hardly damaged.

  Note that the fluororesin constituting the tip 14b is very soft, and it may be deformed by external pressure alone or may be deformed by heat. Therefore, it is very difficult to adjust the target minute gap. However, since the rigidity of the tip portion 14b is ensured by the base material 14a, it does not deform even when an external pressure such as clogging of the recording medium is applied. Further, since the base material 14a extends to the vicinity of the distal end of the distal end portion 14b, the position of the distal end portion 14b can be maintained with high accuracy, and the minute gap between the distal end portion 14b and the pressure roller 4 is distorted due to heat deformation. There is nothing.

  The abutting member 15 is a positioning member having a curvature shape with a radius of curvature R of 0.5 mm at the tip, and is disposed on each end of the holding member 16 that is outside the maximum image area. The pair of abutting members 15 are brought into contact with the pressure roller 4 immediately after the fixing nip portion N by contacting the surface of the pressure roller 4 with a predetermined pressure by the elastic force of the torsion spring 13 as described above. On the other hand, the separation plate 14 can be arranged in a non-contact state.

  As described above, the separation plate unit 6 is configured such that the separation means (the separation plate 14 and the abutting member 15) are rotatably fixed to the unit of the pressure roller 4 around the separation means rotation shaft 10. . The elastic force of the torsion spring 13 acts on the receiving member 16a provided on the separating means side with respect to the separating means rotating shaft 10, whereby the separating means (the separating plate 14 and the abutting member 15) are separated from the separating means rotating shaft 10. , And the abutting member 15 is pressed against the pressure roller 4 so that the tip of the separation plate 14 has a predetermined contact with the pressure roller 4. It is arranged in a non-contact state with a minute gap.

  Further, the separation plate unit 6 sets, for each separation plate 14, the distance (minute gap amount) of the minute gap between the surface of the pressure roller 4 and the tip of the separation plate 14 in the cross section perpendicular to the axial direction of the pressure roller 4. A gap adjusting mechanism for adjusting, and an inclination adjusting mechanism for adjusting the inclination of the tip of the separation plate 14 with respect to the axial direction of the pressure roller 4.

7 and 8 show the specific configuration.
FIG. 7 is a perspective view showing the configuration of the separation plate 14 and its peripheral part in the separation plate unit 6. 7A is an overall view showing a state in which the guide member 1g is removed from the separation plate unit 6 of FIG. 5, and FIG. 7B is an enlarged view showing the configuration of one separation plate 14. FIG.

  As shown in FIG. 7B, the separation plate 14 in the separation plate unit 6 is held by a holding member 16 via a bracket 17 that houses the separation plate 14. A gap adjusting mechanism is provided, and the tilt adjusting mechanism is provided between the bracket 17 and the holding member 16. The bracket 17 is a box-shaped sheet metal processed product (or injection molded product).

  As the gap adjusting mechanism, the distance between the tip of the separating plate 14 and the surface of the pressure roller 4 in the cross section perpendicular to the axial direction (the amount of minute gap) is adjusted by adjusting the adjusting screw 18 disposed on the separating plate 14. ) Can be adjusted.

  Further, as the tilt adjusting mechanism, the tip of the separation plate 14 with respect to the axial direction of the surface of the pressure roller 4 is adjusted by loosening the fixing screw 19 provided on the holding member 16 and adjusting the tilt of the bracket 17 with respect to the pressure roller 4. The tilt position can be adjusted, and then the tilt position can be fixed by tightening the fixing screw 19.

FIG. 8 is an exploded view of the gap adjusting mechanism and the tilt adjusting mechanism of the separation plate 14 shown in FIG.
(Gap adjustment mechanism)
The gap adjusting mechanism is a separation plate rotation support means (a separation plate rotation shaft 14j, a support that rotatably supports the separation plate 14 in a direction in which the tip of the separation plate 14 approaches or separates from the surface of the pressure roller 4 in the bracket 17). The separation plate 14 is positioned at a position where the minute gap between the surface of the pressure roller 4 and the tip of the separation plate 14 becomes a desired distance while urging the separation plate 14 in the rotation direction in the separation plate rotation support means. Separating plate rotation holding means (adjustment screw 18, spring 1a, screw hole 16d).

That is, as shown in FIG. 8, the separation plate 14 has a support hole in which a separation plate rotating shaft 14 j extending in the axial direction of the pressure roller 4 is provided in the bracket 17 on the body portion of the separation plate 14. By being inserted into 17a, it is held by the bracket 17 so as to be rotatable about the separation plate rotation shaft 14j (separation plate rotation support means). Next, the separating plate 14 and the bracket 17 are arranged at predetermined positions of the holding member 16 so that the spring 1a is sandwiched between the holding member 16 (or the bracket 17) and the separating plate 14 by the elastic force of the spring 1a. A rotational moment about the separation plate rotating shaft 14j is applied to the separation plate 14. The adjustment screw 18 is screwed into the screw hole 16d of the holding member 16 through the spring 1a from the through hole 14h provided in the base material 14a of the separation plate 14, and the adjustment screw 18 is screwed into the screw hole 16d. By adjusting the state, it is possible to displace the position of the tip of the separation plate 14 with respect to the surface of the pressure roller 4 in the cross section perpendicular to the axial direction of the pressure roller 4 (separation plate rotation holding means). Note that the direction in which the elastic force of the spring 1a acts (rotational moment about the separation plate rotation shaft 14j) may be the opposite direction to the configuration shown in FIG. 8 (the direction of biasing toward the pressure roller 4). .
By this adjustment operation, the minute gap between the tip end portion 14b and the surface layer of the pressure roller 4 in the cross section perpendicular to the axial direction of the pressure roller 4 is adjusted for each separation plate 14 with analog precision by tightening the adjustment screw 18. be able to.

(Tilt adjustment mechanism)
The inclination adjusting mechanism positions the bracket 17 at a predetermined position in the axial direction of the pressure roller 4 on the holding member 16 and supports the bracket rotation support means so as to be rotatable so as to be inclined with respect to the axial direction of the pressure roller 4. (Bracket rotation boss 16b, bracket rotation hole 17b) and bracket tilt fixing means (fixation) for fixing the bracket 17 rotated by the bracket rotation support means so that the tip of the separation plate 14 is parallel to the surface of the pressure roller 4. The screw 19 is provided with an adjustment hole 16c and a screw hole 17c).

That is, as shown in FIG. 8, the bracket rotation boss 16 b provided on the holding member 16 of the separation plate unit 6 is fitted into the bracket rotation hole 17 b provided on the bracket 17. The holding member 16 is held rotatably about the bracket rotation boss 16b (bracket rotation support means). Next, the rotation position (tilt) of the bracket 17 is fixed by fastening the fixing screw 19 with the screw hole 17c provided in the bracket 17 through the adjustment hole 16c provided in the holding member 16 (bracket tilt fixing means). . That is, in a state where the separation plate unit 6 is attached to the unit of the pressure roller 4, first, the fixing screw 19 fastened to the screw hole 17 c is loosened, and the bracket 17 is rotatable with respect to the holding member 16. The bracket 17 is fixed to the holding member 16 by adjusting the inclination of the tip end portion 14b of the separation plate 14 with respect to the axial direction of the pressure roller 4 and then tightening the fixing screw 19 in the inclined state. The adjustment hole 16c is a hole having a size that allows the screw hole 17c to be screwed with the fixing screw 19 through the adjustment hole 16c even when the bracket 17 rotates.
By this adjustment work, it is possible to adjust the inclination of the tip end portion 14b of the separation plate 14 with respect to the surface layer of the pressure roller 4 and fix the position.

Adjustment of the gap and inclination of the tip end portion 14b for each separation plate 14 in the separation plate unit 6 is performed as follows.
First, when the separation plate unit 6 is mounted on the unit of the pressure roller 4, the gap amount with the pressure roller 4 in the width direction of the front end portion 14b of the separation plate 14 is monitored by a CCD or the like. However, the inclination of the leading end portion 14b of the separation plate 14 is adjusted by the tilt adjusting mechanism described above so that the gap amount with the pressure roller 4 is equal in the width direction of the leading end portion 14b.
Next, the position of the tip 14b relative to the surface of the pressure roller 4 is displaced by the gap adjusting mechanism described above while measuring the gap amount between the tip 14b of the separation plate 14 and the pressure roller 4 with a CCD or the like. The amount of minute gap between the tip end portion 14b and the pressure roller 4 is set to a predetermined value.

  As described above, by performing inclination adjustment and gap adjustment for each of the separation plates 14 provided in a plurality (seven in this embodiment) in the maximum image area, the pressure roller 4 has a normal crown shape or a reverse crown shape. Even if there is, the inclination of the tip end portion 14b with respect to the surface layer of the pressure roller 4 parallel to the axial direction is adjusted at each location where the separation plate 14 is arranged, and in a cross section perpendicular to the axial direction according to the surface layer of the pressure roller 4 Since the minute gap is adjusted, the gap between the front end portion 14b of the separation plate 14 and the surface layer of the pressure roller 4 can be adjusted accurately and uniformly in the entire separation plate unit 6 to improve the separation performance. It becomes possible.

FIG. 9 is a view showing the configuration of the separation plate 14 in the separation plate unit 6 and the guide member 1g arranged on the downstream side in the recording medium conveyance direction. 9A is a perspective view showing the entire configuration of the separation plate unit 6, and FIG. 9B is a cross-sectional view of the separation plate unit 6.
As shown in FIG. 9, the separation plate unit 6 is disposed on the downstream side of the separation plate 14 in the recording medium conveyance direction, and includes a guide member 1g for guiding the recording medium discharged from the fixing nip portion N. On the side of the medium transport path (arrow in FIG. 9B), a part of the guide member 1g extends so as to enter the insertion hole 14c provided in the central portion of the separation plate 14. That is, the guide member 1g has a convex portion 1gt that extends toward the tip end portion 14b of the separation plate 14, and when the guide member 1g is attached to the separation plate unit 6, the convex portion 1gt becomes the separation plate 14. Is inserted into the insertion hole 14c.

  As a result, the end of the guide member 1g usually becomes a step where the leading end of the recording medium is caught downstream of the leading end 14b of the separation plate 14 in the recording medium conveyance direction, causing a paper jam. Since a part of the guide member 1g (projection 1gt) enters the insertion hole 14c and the step is eliminated, the recording medium separated by the separation plate 14 can be smoothly transferred to the guide member 1g downstream thereof, and the separation plate It is possible to prevent a problem that a paper jam occurs in the gap between the guide member 14 and the guide member 1g.

[Separation plate unit (second configuration example)]
Next, a second configuration example of the separation plate unit applied to the fixing device according to the present invention will be described.
In this configuration example, only the configuration of the gap adjustment mechanism and the tilt adjustment mechanism provided for each separation plate 14 is different from that in the first configuration example. Therefore, the configuration of the part as the separation plate unit 6 ′ will be described. .

10 to 12 show the specific configuration.
FIG. 10 is a perspective view showing the configuration of the separation plate 24 and its peripheral portion in the separation plate unit 6 ′. FIG. 10A is an overall view showing a state where the guide member 1g is removed from the separation plate unit 6 ′, and FIG. 10B is an enlarged view showing the configuration of one separation plate 24. FIG.

  As shown in FIG. 10B, the separation plate 24 in the separation plate unit 6 ′ is held by the holding member 16 via a bracket 27 that houses the separation plate 24, and between the separation plate 24 and the bracket 27. The gap adjusting mechanism is provided, and the tilt adjusting mechanism is provided between the bracket 27 and the holding member 16.

  As the gap adjusting mechanism, the distance between the tip of the separating plate 24 and the surface of the pressure roller 4 in the cross section perpendicular to the axial direction (the amount of minute gap) is adjusted by adjusting the adjusting screw 28 disposed on the separating plate 24. ) Can be adjusted.

  Further, as the tilt adjusting mechanism, the tilt of the tip of the separation plate 24 with respect to the axial direction of the surface of the pressure roller 4 can be adjusted by adjusting an adjusting screw 29 provided on the bracket 27.

  FIG. 11 is a diagram illustrating a main configuration example of the separation plate 24. 11A is a perspective view of the separation plate 24, FIG. 11B is a top view of the separation plate 24, and FIG. 11C is a cross-sectional view taken along line AA in FIG. 11B.

  As shown in FIG. 11, the separation plate 24 is made of a material harder than fluororesin and is processed by sheet metal so as to have a predetermined width on the tip side, and the tip of the substrate 24a is softer than the substrate 24a. And a front end portion 24b integrally formed by insert molding of fluororesin. The base material 24a may not be a sheet metal processed product, but may be a hard resin material such as PPS (polyphenylene sulfide resin) or a peak material.

  Here, as for the gap adjusting mechanism, the base 24a has a through hole 24h provided at the end opposite to the tip 24b, and the width of the tip 24b between the tip 24b and the through hole 24h. A separating plate rotating shaft 24j (not shown) is provided extending in both directions corresponding to the direction. The separation plate rotating shaft 24j is fixed to the base material 24a as a separate member. In addition, an insertion hole 24c into which a part of the guide member 2g (projection 2gt) or the driven roller 2gr is inserted is provided at the center in the width direction on the front end 24b side of the substrate 24a.

  The tip 24b is made of a fluororesin that is excellent in heat resistance and toner releasability. In particular, by using tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) having high releasability, it becomes more advantageous for toner accumulation and adhesion, and toner accumulation and adhesion on the surface layer of the tip 24b is prevented. Therefore, the toner does not rub against the image surface at the front end portion 24b to become an abnormal image, and a good image quality can be obtained. Moreover, since the resin excellent in non-aggressiveness is used for the front-end | tip part 24b, malfunctions, such as scratching a partner member, can be prevented. Furthermore, since the tip end portion 24b is excellent in slidability with the pressure roller 4, even if the tip end portion 24b contacts the pressure roller 4, the pressure roller 4 is hardly damaged.

  Since the rigidity of the tip 24b is secured by the base material 24a, it does not deform even when an external pressure such as clogging of the recording medium is applied. Further, since the base material 24a extends to the vicinity of the distal end of the distal end portion 24b, the position of the distal end portion 24b can be maintained with high accuracy, and the minute gap between the distal end portion 24b and the pressure roller 4 is distorted due to heat deformation. There is nothing.

12 is an exploded view of the gap adjusting mechanism and the tilt adjusting mechanism of the separation plate 24 shown in FIG.
(Gap adjustment mechanism)
The gap adjusting mechanism is a separation plate rotation support means (a separation plate rotation shaft 24j, a support that rotatably supports the separation plate 24 in a direction in which the tip of the separation plate 24 approaches or separates from the surface of the pressure roller 4 in the bracket 27). The separation plate 24 is positioned at a position where the minute gap between the surface of the pressure roller 4 and the tip of the separation plate 24 is a desired distance while urging the separation plate 24 in the rotation direction in the separation plate rotation support means. Separating plate rotation holding means (adjustment screw 28, spring 2a, screw hole 16d).

That is, as shown in FIG. 12, the separation plate 24 has a support hole in which a separation plate rotation shaft 24 j extending in the axial direction of the pressure roller 4 is provided in the bracket 27. By being inserted into 27a, it is held by the bracket 27 so as to be rotatable about the separation plate rotation shaft 24j (separation plate rotation support means). Next, the separating plate 24 and the bracket 27 are arranged at predetermined positions of the holding member 16 so that the spring 2a is sandwiched between the bracket 27 and the separating plate 24, and the separating plate 24 is separated by the elastic force of the spring 2a. A rotation moment about the rotation axis 24j is applied. The adjustment screw 28 is screwed into the screw hole 16d of the holding member 16 through the spring 2a from the through hole provided in the base material of the separation plate 24, and the screwed state of the adjustment screw 28 into the screw hole 16d is changed. By adjusting, it becomes possible to displace the position of the tip of the separation plate 24 with respect to the surface of the pressure roller 4 in the cross section perpendicular to the axial direction of the pressure roller 4 (separation plate rotation holding means). Note that the direction in which the elastic force of the spring 2a acts (rotational moment about the separation plate rotation shaft 24j) may be the opposite direction to the configuration shown in FIG. 12 (the direction of biasing toward the pressure roller 4). .
By this adjustment operation, a minute gap between the tip 24b and the surface layer of the pressure roller 4 in the cross section perpendicular to the axial direction of the pressure roller 4 is adjusted for each separation plate 24 with an analog precision by tightening the adjustment screw 28. be able to.

(Tilt adjustment mechanism)
The inclination adjusting mechanism positions the bracket 27 at a predetermined position in the axial direction of the pressure roller 4 on the holding member 16 and supports the bracket rotation support means to rotatably support the bracket 27 so as to be inclined with respect to the axial direction of the pressure roller 4. (The bracket rotating shaft 2j, the bracket rotating hole 27b) and the bracket 27 at the position where the tip of the separation plate 24 is parallel to the surface of the pressure roller 4 while urging the bracket 27 in the rotating direction in the bracket rotating support means. Bracket inclination holding means for holding (adjustment screw 29, spring 2b, screw hole).

That is, as shown in FIG. 12, the bracket rotation hole 27 b provided in the bracket 27 in a direction orthogonal to the width direction of the separation plate 24 is orthogonal to the axial direction of the pressure roller 4 in the holding member 16. The bracket rotation shaft 2j extending in the direction of the insertion is inserted, and the bracket 27 and the separation plate 24 are held at predetermined positions of the holding member 16 so as to be rotatable about the bracket rotation shaft 2j (bracket rotation). Support means). Next, as a state in which the spring 2b is sandwiched between the bracket 27 and the holding member 16, a rotational moment about the bracket rotation axis 2j is applied to the bracket 27 by the elastic force of the spring 2b. An adjustment screw 29 is screwed into a screw hole (not shown) of the holding member 16 through a spring 2b from a through hole provided in the bracket 27, and the screwed state of the adjustment screw 29 into the screw hole is adjusted. This makes it possible to displace the inclination of the tip of the separation plate 24 with respect to the axial direction of the pressure roller 4 (bracket inclination holding means).
By this adjustment operation, the inclination of the front end portion 24b of the separation plate 24 with respect to the surface layer of the pressure roller 4 can be adjusted with analog precision by adjusting the adjustment screw 29.

Adjustment of the gap and inclination of the tip 24b for each separation plate 24 in the separation plate unit 6 ′ is performed as follows.
First, when the separation plate unit 6 ′ is mounted on the unit of the pressure roller 4, the gap amount with the pressure roller 4 in the width direction of the front end portion 24b of the separation plate 24 is monitored by a CCD or the like. However, the inclination adjustment mechanism described above adjusts the inclination of the tip 24b of the separation plate 24 so that the gap with the pressure roller 4 is equal in the width direction of the tip 24b.
Next, the position of the tip 24b relative to the surface of the pressure roller 4 is displaced by the gap adjusting mechanism described above while measuring the gap amount between the tip 24b of the separation plate 24 and the pressure roller 4 with a CCD or the like. The amount of minute gap between the tip 24b and the pressure roller 4 is set to a predetermined value.

  As described above, by performing inclination adjustment and gap adjustment on each of the separation plates 24 provided in a plurality (nine in the present embodiment) in the maximum image area, the pressure roller 4 has a normal crown shape or a reverse crown shape. Even if there is, the inclination of the tip end portion 24b with respect to the surface layer of the pressure roller 4 parallel to the axial direction is adjusted at each location where the separation plate 24 is arranged, and in a cross section perpendicular to the axial direction according to the surface layer of the pressure roller 4 Since the minute gap is adjusted, the gap between the tip 24b of the separation plate 24 and the surface layer of the pressure roller 4 can be adjusted accurately and uniformly throughout the separation plate unit 6 ′, and the separation performance can be improved. Is possible.

FIG. 13 is a diagram illustrating a configuration example (1) of the separation plate 24 and the guide member 2g disposed on the downstream side in the recording medium conveyance direction in the separation plate unit 6 ′. Among these, FIG. 13A is a perspective view showing the entire configuration of the separation plate unit 6 ′, and FIG. 13B is a cross-sectional view of the separation plate unit 6 ′.
As shown in FIG. 13, the separation plate unit 6 ′ is disposed on the downstream side of the separation plate 24 in the recording medium conveyance direction, and includes a guide member 2 g that guides the recording medium discharged from the fixing nip portion N. On the side of the recording medium conveyance path (arrow in FIG. 13B), a part of the guide member 2g extends so as to enter an insertion hole 24c provided in the central portion of the separation plate 24. That is, the guide member 2g has a convex portion 2gt extending toward the tip end portion 24b of the separation plate 24. When the guide member 2g is mounted on the separation plate unit 6 ′, the convex portion 2gt is separated from the separation plate unit 6 ′. 24 is inserted into the insertion hole 24c.

  As a result, the end of the guide member 2g normally becomes a step where the leading end of the recording medium is caught on the downstream side of the leading end 24b of the separation plate 24 in the recording medium conveyance direction, causing a paper jam. Since part of the guide member 2g (projection 2gt) enters the insertion hole 24c and the step is eliminated, the recording medium separated by the separation plate 24 can be smoothly transferred to the guide member 2g downstream thereof, and the separation plate It is possible to prevent a problem that a paper jam occurs in the gap between the guide member 2g and 24.

  FIG. 14 is a diagram showing a configuration example (2) of the separation plate 24 and the guide member 2g ′ arranged on the downstream side in the recording medium conveyance direction in the separation plate unit 6 ″. Among these, FIG. 14A is a perspective view showing the entire configuration of the separation plate unit 6 ″, and FIG. 14B is an enlarged perspective view of the separation plate 24 in the separation plate unit 6 ″.

  The separation plate unit 6 ″ differs from the separation plate unit 6 ′ only in the configuration relating to the guide of the recording medium. As shown in FIG. 14, the separation plate 24 is placed on the conveyance path side of the recording medium on the driven roller 2gr. have. Accordingly, as shown in FIG. 15, when the separation plate unit 6 '' is arranged on the fixing belt 2 side, the recording medium is separated by the front end portion 24b of the separation plate 24 at the outlet of the fixing nip portion N, and then the driven roller 2gr. However, since the recording medium is separated from the separation plate 24, it is possible to prevent a problem that the recording medium rubs strongly against the separation plate 24 and causes a separation plate rubbing mark or the like on the image.

Next, the image forming apparatus according to the present invention will be described.
FIG. 16 is a cross-sectional view showing the configuration of the image forming apparatus according to the present invention.
The image forming apparatus 100 is a tandem color image forming apparatus, and includes a copying apparatus main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400, as shown in FIG.

The copying apparatus main body 150 is provided with an endless belt-like intermediate transfer member 50 at the center. The intermediate transfer member 50 is stretched around the support rollers 114, 115 and 116, and can rotate clockwise in FIG. A cleaning device 117 for removing residual toner on the intermediate transfer member 50 is disposed in the vicinity of the support roller 115. On the intermediate transfer member 50 stretched by the support roller 114 and the support roller 115, four image forming units 118 of yellow, cyan, magenta, and black are arranged opposite to each other along the conveyance direction. A means 120 is arranged. An exposure device 121 is disposed in the vicinity of the image forming unit 120, and a secondary transfer device 122 is disposed on the side of the intermediate transfer member 50 opposite to the side on which the image forming unit 120 is disposed. . In the secondary transfer device 122, a secondary transfer belt 124, which is an endless belt, is stretched around a pair of support rollers 123, and the recording medium conveyed on the secondary transfer belt 124 and the intermediate transfer member 50 are mutually connected. It is possible to touch. The fixing device 20 of the present invention is disposed downstream of the secondary transfer device 122 in the recording medium conveyance direction.
A reversing device 128 for reversing the recording medium is disposed downstream of the fixing device 20 in the recording medium conveyance direction in order to form images on both sides of the recording medium.

  Next, formation of a full-color image (color copy) using the image forming unit 120 will be described. First, a document is set on a document table of an automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened, and a document is set on the contact glass 132 of the scanner 300. close.

  When a start switch (not shown) is pressed, when a document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 132, and then the document is set on the contact glass 132. When this happens, the scanner 300 is immediately driven, and the first traveling body 133 and the second traveling body 134 travel. At this time, light from the light source is irradiated by the first traveling body 133, and reflected light from the document surface is reflected by a mirror in the second traveling body 134. Further, the image is received by the reading sensor 136 through the imaging lens 135, and the document is read to obtain black, yellow, magenta and cyan image information. Next, each image information is transmitted to each image forming unit 118 in the image forming means 120, and a visible image of each color of black, yellow, magenta and cyan is formed.

  The image forming unit 118 is formed by exposing the photoconductor to each image on the basis of each image information by a photoconductor, a charging device for uniformly charging the photoconductor, and an exposure device. The latent image is developed using each toner (black toner, yellow toner, magenta toner, and cyan toner) to form a visible image with each toner, and the visible image is transferred onto the intermediate transfer member 50. A transfer charger, a cleaning device, and a charge removal device, and a visible image of each color can be formed based on each image information. Next, the visible images of the respective colors are sequentially transferred (primary transfer) onto the intermediate transfer body 50 that is rotated by the support rollers 114, 115, and 116, and the visible images of the respective colors are superimposed to form a composite transfer image. It is formed.

  On the other hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed the recording medium from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143, and one sheet at a time by the separation roller 145. The paper is separated and sent to the paper feed path 146, transported by the transport roller 147, guided to the paper feed path 148 in the copying apparatus main body 150, and abutted against the registration roller 149 to stop. Alternatively, the paper feed roller 142 is rotated to feed out the recording medium on the manual feed tray 153 a, separated one by one by the separation roller 152, put into the manual paper feed path 153, and abutted against the registration roller 149 and stopped. The registration roller 149 is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the recording medium. Then, the registration roller 149 is rotated in time with the composite transfer image formed on the intermediate transfer member 50, and a recording medium is sent between the intermediate transfer member 50 and the secondary transfer device 122, and the secondary transfer device. By transferring (secondary transfer) the composite transfer image onto the recording paper by 122, a color image is formed on the recording medium. The toner remaining on the intermediate transfer member 50 is removed by the cleaning device 117.

  The recording medium on which the color image is formed is conveyed by the secondary transfer device 122 and sent to the fixing device 20, where the composite transfer image is heated and pressed and fixed on the recording medium. Thereafter, the recording medium is switched by the switching claw 155 and discharged by the discharge roller 156, and is stacked on the discharge tray 157. Alternatively, it is switched by the switching claw 155, reversed by the reversing device 128, led again to the transfer position, and an image is also formed on the back surface, then discharged by the discharge roller 156, and stacked on the discharge tray 157.

  According to the image forming apparatus of the present invention, since the fixing device of the present invention is provided, it is possible to stably form an image without causing a jam at the fixing nip portion N.

  Although the present invention has been described with the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, modifications, deletions, etc. Can be changed within the range that can be conceived, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.

  For example, as a configuration of the gap adjustment mechanism and the inclination adjustment mechanism in the separation plate units 6 and 6 ′, the separation plate 14 is held by the holding member 16 via the bracket 17 (27) that houses the separation plate 14 (24). The tilt adjusting mechanism may be provided between (24) and the bracket 17 (27), and the gap adjusting mechanism may be provided between the bracket 17 (27) and the holding member 16.

  Further, the separation plate units 6 and 6 ′ may be disposed on the fixing member (the fixing belt 2 or a fixing roller in the case of the fixing roller system), or the separation plate unit 6 ″ may be disposed on the pressure roller 4 side. You may arrange.

  Examples of utilization of the present invention include a fixing device for OA equipment and a unit member that requires clearance adjustment with respect to a roller in a developing / cleaning mechanism.

DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Fixing belt 3 Heating roller 3h, 4h Heater 4 Pressure roller 5, 6, 6, 6 ', 6''Separation plate unit 7 Relay discharge guide lower unit 8 Paper discharge guide plate unit 9 Entrance guide plate 10 Separating means rotating shaft 11 rotating bearing groove 12 tension spring 13 torsion spring 14, 24 separating plate 14a, 24a base material 14b, 24b tip 14c, 24c insertion hole 14h, 24h through hole 14j, 24j separating plate rotating shaft 15 abutting member 16 holding member 16a receiving member 16b bracket rotating boss 16c adjusting hole 16d, 17c screw hole 17, 27 bracket 17a, 27a supporting hole 17b, 27b bracket rotating hole 18, 28, 29 adjusting screw 19 fixing screw 1a, 2a, 2b spring 1g , 2g, 2g 'guide member 1gt, gt convex portion 2gr driven roller 2j bracket rotating shaft 20 fixing device 20f fixing side plate 50 intermediate transfer member 70 support jig 100 image forming device 114, 115, 116, 123 support roller 117 cleaning device 118 image forming unit 120 image forming means 121 exposure Device 122 Secondary transfer device 124 Secondary transfer belt 128 Reversing device 132 Contact glass 133 First traveling body 134 Second traveling body 135 Imaging lens 136 Reading sensor 142 Paper feed roller 143 Paper bank 144 Paper feed cassette 145 Separation roller 146 Feed Paper path 147 Conveying roller 148 Paper feed path 149 Registration roller 150 Copier main body 152 Separation roller 153 Manual paper feed path 153a Manual feed tray 155 Switching claw 156 Discharge roller 157 Discharge tray 2 00 Paper feed table 300 Scanner 400 Automatic document feeder (ADF)
N Fixing nip

Japanese Patent No. 2823168 JP 2006-11193 A

Claims (10)

Two rotating bodies that are pressed to form a fixing nip,
A plurality of separation plates; and a holding member that holds the plurality of separation plates side by side in the axial direction of the rotator, and the separation plate is disposed on the rotator side of at least one of the two rotators. A separation plate unit arranged so as to be in a non-contact state,
The separation plate unit includes, for each separation plate, a gap adjusting mechanism that adjusts a distance of a minute gap between the surface of the rotating body and a tip of the separating plate in a cross section perpendicular to the axial direction of the rotating body, and the rotating body. And a tilt adjusting mechanism that adjusts the tilt of the tip of the separating plate with respect to the axial direction of the fixing plate. The separation plate is held by the holding member via a bracket that houses the separation plate,
The fixing device according to claim 1, wherein the gap adjustment mechanism is provided between the separation plate and the bracket, and the inclination adjustment mechanism is provided between the bracket and the holding member.   The tilt adjustment mechanism includes a bracket rotation support means for positioning the bracket at a predetermined position in the axial direction of the rotating body on the holding member and rotatably supporting the bracket so as to tilt with respect to the axial direction of the rotating body. The bracket tilt fixing means for fixing the bracket rotated by the bracket rotation support means so that the front end of the separation plate is parallel to the surface of the rotating body. Fixing device.   The tilt adjustment mechanism includes a bracket rotation support means for positioning the bracket at a predetermined position in the axial direction of the rotating body on the holding member and rotatably supporting the bracket so as to tilt with respect to the axial direction of the rotating body. A bracket tilt holding means for holding the bracket at a position where the tip of the separation plate is parallel to the surface of the rotating body while urging the bracket in the rotation direction in the bracket rotation support means. The fixing device according to claim 2.   The gap adjusting mechanism includes: a separation plate rotation support unit that rotatably supports the separation plate in a direction in which the tip of the separation plate approaches or separates from the rotating body in the bracket; and the separation plate rotation support unit. Separating plate rotating and holding means for holding the separating plate at a position where a minute gap between the surface of the rotating body and the tip of the separating plate becomes a desired distance while urging the separating plate in the rotation direction thereof. The fixing device according to claim 2, wherein:   The separation plate unit is provided with a pair of abutting members that abut against the rotating body and hold the tips of the plurality of separation plates in a non-contact state separated from the rotating body by a minute gap. The fixing device according to claim 1, wherein the fixing device is a magnetic head.   7. The separation plate according to claim 1, wherein a hard base material and a tip portion made of a fluororesin softer than the base material are integrally formed by insert molding. Fixing device.   The separation plate unit is disposed on the downstream side of the separation plate in the recording medium conveyance direction, and has a guide member for guiding the recording medium discharged from the fixing nip portion. The fixing device according to claim 1, wherein a part of the guide member extends so as to enter a hole provided in a central portion of the separation plate.   The fixing device according to claim 1, wherein the separation plate has a driven roller on a conveyance path side of the recording medium.   An image forming apparatus comprising the fixing device according to claim 1.