JP2018018112A - Separating member, fixing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separating member capable of effectively suppressing reduction in accuracy of a gap formed with a fixing rotating body or a pressure rotating body, a fixing device including the separating member, and an image forming apparatus including the fixing device.SOLUTION: A separating member 95 includes a separating plate 96 that is arranged downstream of a fixing nip part N so that one end part 96g faces an outer peripheral surface F of a fixing belt 92A. The separating member 95 also includes a plate-like gap forming member 97 that is arranged across a partial portion on both ends of the one end part 96g of the separating plate 96 in a direction to intersect with an extending direction of the one end part 96g, so as to be held between the partial portions and the outer peripheral surface F of the fixing belt 92A.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a separation member, a fixing device including the separation member, and an image forming apparatus including the fixing device.

  In an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a composite machine thereof, an electrostatic latent image formed on an image carrier is developed by a developing device, and the toner image is transferred onto a recording medium. In some cases, the image is formed by fixing with a fixing device.

  Such a fixing device includes a fixing rotator such as a fixing roller and a fixing belt, and a pressure roller that is disposed opposite to the fixing rotator and is pressed against the fixing rotator to form a fixing nip portion. A pressure rotating body. The fixing device conveys the recording medium while sandwiching the recording medium by a fixing nip portion formed between the fixing rotator and the pressure rotator, and fixes the toner image on the recording medium by heat and pressure.

  Further, in the fixing device, in order to prevent the recording medium that has passed through the fixing nip portion from being wound around the fixing rotator or the pressure rotator (hereinafter referred to as “fixing rotator etc.”), the fixing rotator or the like. A separating member for separating the recording medium from the recording medium is provided. The separating member is formed, for example, in a substantially strip shape, and is arranged in parallel to the axial direction of the fixing rotator and the one edge portion in the short direction is close to the outer peripheral surface of the fixing rotator and the like. It is opposed with a gap.

  A minute gap (gap) is provided between one edge of the separating member and the outer peripheral surface of the fixing rotator or the like. If the gap is narrow, the separation member and the fixing rotator come into contact with each other, and stress is applied to the fixing rotator. If the gap is wide, the recording medium passes through the gap and the recording medium is wound around the fixing rotator or the like. Therefore, the separating member includes a positioning mechanism for providing an appropriate gap with the fixing rotator and the like.

  For example, the separation member 817 included in the fixing device disclosed in Patent Document 1 includes a strip-shaped separation plate 830 and a bracket 831 that supports the separation plate 830, as shown in FIGS. ing. Separation plate 830 is attached so as to overlap with outer surface 831 a of bracket 831, and one edge portion 830 a in the short-side direction is arranged so as to protrude from the edge portion of bracket 831. Further, the separation plate 830 has a fluororesin layer 832 formed on the surface. The separation member 817 includes positioning members 836 that are integrally formed at both ends of the separation plate 830 by bending or the like. When the positioning member 836 is abutted against the rotation shaft 838 of the fixing roller 837, the positioning member 836 is positioned between the one edge portion 830 a (specifically, the fluororesin layer 832 superimposed on the one edge portion 830 a) and the fixing roller 837. The shape and the like are determined so that a predetermined gap is provided in the case.

  Further, as shown in FIGS. 12 to 14, the separating member 938 provided in the fixing device disclosed in Patent Document 2 has positioning members 939 (abutting members) attached to both ends. The positioning member 939 has a shape so that a predetermined gap is provided between the one edge portion 938a of the separation member 938 and the fixing roller 921 when being brought into contact with both end portions of the outer peripheral surface of the fixing roller 921. Etc. have been determined.

  However, in the separation member 817 of Patent Document 1, from one edge portion 830a of the separation plate 830 that forms a gap with the fixing roller 837 (specifically, from the fluororesin layer 832 superimposed on the one edge portion 830a). A positioning member 836 is provided at a remote location. Therefore, for example, the shape tolerance of the positioning member 836 and the shape tolerance of the separation plate 830 affect the gap, and there is a problem that the accuracy of the gap may be lowered.

  Also in the separation member 938 of Patent Document 2, a positioning member 939 is provided at a position away from one edge portion 938 a of the separation member 938 that forms a gap with the fixing roller 921. Therefore, similarly to the above, the shape tolerance and mounting tolerance of the positioning member 939 and the shape tolerance of the separating member 938 affect the gap, and there is a problem that the accuracy of the gap may be reduced. .

  Therefore, the present invention provides a separation member that can effectively suppress a decrease in accuracy of a gap between the fixing rotator or the pressure rotator, a fixing device including the separation member, and an image including the fixing device. It is an object to provide a forming apparatus.

  In order to solve the above-described problem, the invention described in claim 1 is directed to a fixing rotator for fixing an unfixed image on a recording medium, and the recording between the fixing rotator and the fixing rotator. A pressure rotator that forms a fixing nip portion in which a medium is sandwiched, and a separation member used in a fixing device, wherein an outer peripheral surface of the fixing rotator or the pressure rotator is provided downstream of the fixing nip portion. A separation plate that is arranged so that an outer peripheral surface of the separation plate faces one edge, a part of the one edge of the separation plate, and an outer peripheral surface of the fixing rotator or an outer peripheral surface of the pressure rotator. A plate-like gap forming member disposed across the part in a direction crossing the extending direction of the one edge so as to be sandwiched therebetween, and the gap forming member has flexibility. A portion of the gap forming member made of a material having The other part of the gap forming member attached to one surface of the separation plate and spaced from the part of the gap forming member is attached to the other surface of the separation plate, and the part of the gap forming member and the other part of the gap forming member. Between the gap forming member and the gap forming member in a cross-sectional view in a direction orthogonal to the extending direction. The straddling portion is in contact with the outer peripheral surface of the fixing rotator or the outer peripheral surface of the pressure rotator to form a gap between the separation plate and the fixing rotator or the pressure rotator. It is the separation member characterized by being comprised.

  According to the first aspect of the present invention, the separation plate is disposed on the outer peripheral surface of the fixing rotator or the pressure rotator downstream of the fixing nip formed between the fixing rotator and the pressure rotator. The outer peripheral surface (hereinafter referred to as “the outer peripheral surface of the fixing rotator or the like”) and one edge portion are arranged to face each other. Then, the part of the separation plate is extended to the edge of the separation plate so that the plate-shaped gap forming member is sandwiched between the part of the edge of the separation plate and the outer peripheral surface of the fixing rotating body or the like. It is arranged across the direction intersecting the current direction. Thus, when the gap forming member is sandwiched between the part and the outer peripheral surface of the fixing rotator or the like, the part other than the part and the fixing rotator at one edge of the separation plate A gap corresponding to the thickness of the gap forming member is formed between the outer peripheral surface and the like. Therefore, since this gap is determined by the thickness of the gap forming member, it is possible to avoid the influence of many shape tolerances and mounting tolerances on the gap, and to effectively suppress a decrease in gap accuracy. In addition, since the gap size can be controlled by the thickness of the gap forming member, the gap size can be easily adjusted.

It is a figure explaining the structure of the separation member of one Embodiment of this invention, Comprising: (a) is a perspective view, (b) is the expansion perspective view which expanded a part of (a), c) is a side view. It is a figure explaining the structure of the separating plate with which the separating member of FIG. 1 is equipped, Comprising: (a) is a perspective view, (b) is the expansion perspective view which expanded a part of (a), c) is a side view. It is a figure explaining the structure of the gap formation member with which the separation member of FIG. 1 is equipped, Comprising: (a) is a perspective view, (b) is sectional drawing. FIGS. 2A and 2B are diagrams for explaining a state in which the separation member of FIG. 1 is disposed to face the fixing belt, in which FIG. 1A is a front view, and FIG. 1B is an enlarged front view in which a part of FIG. (C) is an enlarged side view. 1 is a schematic configuration diagram of a fixing device according to an embodiment of the present invention. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a schematic block diagram of the process cartridge with which the image forming apparatus of FIG. 6 is provided. It is a figure explaining the structure of the modification of the separation member of FIG. 1, Comprising: (a) is a perspective view, (b) is the expansion perspective view which expanded a part of (a), (c ) Is a side view. It is a side view of the conventional separation member. FIG. 10 is a perspective view of the separation member of FIG. 9. FIG. 10 is a perspective view showing a positional relationship between a separation member and a fixing roller in FIG. 9. It is a perspective view of the other conventional separation member. It is a front view of the separation member of FIG. It is an expansion perspective view of the separation member of FIG.

(Embodiment of separation member)
Hereinafter, a separation member according to an embodiment of the present invention will be described with reference to FIGS.

  FIGS. 1A and 1B are diagrams illustrating a configuration of a separation member according to an embodiment of the present invention, in which FIG. 1A is a perspective view and FIG. 1B is an enlarged perspective view in which a part of FIG. (C) is a side view. 2A and 2B are diagrams for explaining the configuration of a separation plate provided in the separation member of FIG. 1, wherein FIG. 2A is a perspective view, and FIG. 2B is an enlarged perspective view in which a part of FIG. (C) is a side view. 3A and 3B are views for explaining the configuration of the gap forming member provided in the separation member of FIG. 1, wherein FIG. 3A is a perspective view and FIG. 3B is a cross-sectional view. 4A and 4B are views for explaining a state in which the separation member of FIG. 1 is arranged to face the fixing belt, wherein FIG. 4A is a front view, and FIG. 4B is a part of FIG. It is the enlarged front view which expanded, (c) is an enlarged side view.

  The separation member of the present embodiment includes a fixing belt that fixes a toner image on a recording medium, a pressure roller that is pressed against the fixing belt and forms a fixing nip portion between which the recording medium is sandwiched. It is used for a fixing device provided with In this embodiment, the separation member is disposed downstream of the fixing nip portion so that a predetermined gap is provided between the separation member and the fixing belt. Thereby, the separation member separates the recording medium from the fixing belt and suppresses the winding of the recording medium around the fixing belt.

  As shown in FIGS. 1A to 1C, the separation member 95 includes a separation plate 96 and a pair of gap forming members 97.

  As illustrated in FIGS. 2A to 2C, the separation plate 96 includes a separation plate main body 96 a and a pair of support portions 96 b.

  The separation plate main body 96a is formed in a substantially band plate shape by sheet metal or the like, for example. At both ends in the longitudinal direction of the separation plate main body 96a, a hooking claw 96c to which the other end 97b of the gap forming member 97 described later is hooked, and one end 97a of the gap forming member 97 are screwed (FIG. 1 (c)). A screw hole 96d to be screwed is provided. The hooking claw 96c protrudes toward the one surface 96e (that is, the paper passing surface) of the separation plate main body 96a.

  The pair of support portions 96b are integrally provided at both ends in the longitudinal direction of the separation plate main body 96a so as to protrude toward the other surface 96f of the separation plate main body 96a. The pair of support portions 96b are attached to the frame or the like of the fixing device 9 to be described later, and support the separation plate main body 96a in a swingable manner.

  In the separating plate 96, a predetermined gap G is provided between one edge portion 96g of the separating plate main body 96a in the short direction (vertical direction in FIGS. 1 and 2) and a fixing belt 92A of the fixing device 9 described later. As described above, the fixing belt 92A is disposed in the vicinity. In the separation plate 96, the vicinity of one edge portion 96g on one surface 96e is formed flat, and the vicinity of the one edge portion 96g on the other surface 96f is the extending direction of the one edge portion 96g (that is, the longitudinal direction of the separation plate body 96a). (Direction) is formed in a shape cut out throughout.

  As shown in FIG. 3A, the gap forming member 97 is a resin sheet material formed in a substantially band plate shape. As shown in FIG. 3B, the gap forming member 97 is configured by forming a surface layer 97B on the surface of the base material 97A. The base material 97A is made of, for example, flexible synthetic resin such as acrylic or polyester. The surface layer 97B is made of, for example, a fluorine-based resin such as PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) or PTFE (polytetrafluoroethylene). In the present embodiment, the thickness of the gap forming member 97 is set to 0.3 mm. Of course, the thickness of the gap forming member 97 is not limited to this, and is arbitrarily set according to the gap width provided between the separating member 95 and the fixing belt 92A.

  Each of the pair of gap forming members 97 is attached to both ends in the longitudinal direction of the separation plate main body 96 a of the separation plate 96. Specifically, a claw receiving hole 97c provided in one end portion 97a of the gap forming member 97 is hooked on the hooking claw 96c of the separation plate main body 96a. As a result, the one end 97a of the gap forming member 97 is attached to the one surface 96e of the separation plate main body 96a in a semi-fixed state (a state in which some displacement is possible with respect to the attachment position). Further, a screw 99 inserted through a screw through hole 97d provided in the other end 97b of the gap forming member 97 is screwed into the screw hole 96d of the separation plate main body 96a. Thus, the other end 97b of the gap forming member 97 is fixedly attached to the other surface 96f of the separation plate main body 96a. That is, the pair of gap forming members 97 are detachably attached to the separation plate 96.

  An intermediate portion 97e between the claw receiving hole 97c of the gap forming member 97 and the screw through hole 97d is curved and a part of both ends of one edge portion 96g of the separation plate main body 96a is formed from the one surface 96e side. It arrange | positions so that the other surface 96f side may be straddled. In other words, the intermediate portion 97e of the gap forming member 97 is a direction that intersects both ends of the one edge portion 96g of the separation plate main body 96a with the extending direction of the one edge portion 96g (matches the longitudinal direction of the separation plate 96). It is arranged across. The pair of gap forming members 97 are in contact with the outside of the toner image fixing region on the outer peripheral surface F of the fixing belt 92A when the separating member 95 is attached to the fixing device 9. The mounting interval and the mounting position are set. Here, the fixing area means an area that is pressed and heated in contact with the recording medium S. In the present embodiment, the pair of gap forming members 97 are disposed so as to be in contact with both ends in the width direction of the fixing belt 92A. The one end portion 97a of the gap forming member 97 corresponds to an example of a part of the gap forming member. The other end 97b of the gap forming member 97 corresponds to an example of another part of the gap forming member.

  Next, the effect | action of the separation member 95 of this embodiment is demonstrated with reference to Fig.4 (a)-(c).

  The separating member 95 is arranged so that the longitudinal direction of the separating plate 96 is parallel to the width direction of the fixing belt 92A (the left-right direction in FIGS. 4A and 4B, the front-back direction in FIG. 4C). Has been. Further, the separation member 95 is disposed downstream of the fixing nip portion N (not shown in FIG. 4). The separating member 95 is a direction in which one edge portion 96g of the separating plate 96 (specifically, the separating plate body 96a) approaches the outer peripheral surface F of the fixing belt 92A with the tips of the pair of support portions 96b as the rotation center. A force is applied by an elastic member such as a torsion spring (not shown) so as to rotate toward the center.

  Therefore, at both ends in the longitudinal direction of the edge 96g of the separation plate 96, the edge 96g is pressed against the outer peripheral surface F of the fixing belt 92A via the pair of gap forming members 97. At this time, one edge portion 96 g of the separation plate 96 is brought into contact with the inner peripheral surfaces of the pair of gap forming members 97. That is, the pair of gap forming members 97 is sandwiched between the both ends of the one edge portion 96g of the separation plate 96 and the outer peripheral surface F of the fixing belt 92A. As a result, a gap G corresponding to the thickness of the pair of gap forming members 97 is formed between the portion between the pair of gap forming members 97 at one edge 96g of the separation plate 96 and the outer peripheral surface F of the fixing belt 92A. Is done.

  The gap G formed in this way includes the shape tolerance (excluding thickness) and attachment tolerance of the gap forming member 97, and the shape tolerance of the separator 96 (specifically, the attachment position and one edge of the gap forming member 97). No influence of misalignment with 96 g). Since the gap G depends only on the thickness of the gap forming member 97, the gap G can be provided with high accuracy by managing the accuracy of the thickness of the gap forming member 97.

  Further, since the pair of gap forming members 97 is attached to the separating plate 96 in a semi-fixed state in the separating member 95, the position and posture of the pair of gap forming members 97 are appropriately autonomous with the rotation of the fixing belt 92A. Adjusted. This eliminates the need for fine adjustment of the attachment positions of the pair of gap forming members 97 and improves assemblability.

  As described above, according to the separation member 95 of the present embodiment, the separation plate 96 is provided downstream of the fixing nip portion N so that the outer peripheral surface F of the fixing belt 92A and the one edge portion 96g face each other. In addition, the separating member 95 extends at one edge 96g at a part of the separation plate 96 so that the separation member 95 is sandwiched between a part at both ends of the edge 96g of the separation plate 96 and the outer peripheral surface F of the fixing belt 92A. And a plate-like gap forming member 97 arranged across the direction intersecting the direction. As a result, when the gap forming member 97 is sandwiched between the part and the outer peripheral surface F of the fixing belt 92A, the part other than the part in the edge 96g of the separation plate 96 and the fixing belt 92A. Between the outer peripheral surface F, a gap G corresponding to the thickness of the gap forming member 97 is formed. Therefore, since the gap G is determined by the thickness of the gap forming member 97, it is possible to avoid the influence of many shape tolerances and mounting tolerances on the gap G, and to effectively suppress a decrease in the accuracy of the gap G. it can. Further, since the size of the gap G can be controlled by the thickness of the gap forming member 97, the size of the gap G can be easily adjusted.

  The gap forming member 97 is made of a flexible material. One end 97 a of the gap forming member 97 is attached to one surface 96 e of the separation plate 96. The other end portion 97 b spaced from the one end portion 97 a of the gap forming member 97 is attached to the other surface 96 f of the separation plate 96. An intermediate portion 97e between the one end portion 97a and the other end portion 97b of the gap forming member 97 is bent and arranged so as to straddle the one part of the one edge portion 96g. As a result, the positioning accuracy of the gap forming member 97 is eased compared to a configuration in which the gap forming member 97 is fixed to the separation plate 96 as a whole, and the gap forming member 97 can be easily attached to the separation plate 96. It becomes possible to attach to, and assembly property can be improved. In addition, since the flexible gap forming member 97 is attached to both surfaces of the separation plate 96, the gap forming member 97 can be moved when the separation plate 96 protrudes from the fixing belt 92A as compared with a structure in which the separation plate 96 is attached to only one surface. Drowning can be suppressed.

  A gap forming member 97 is detachably attached to the separation plate 96. Since this makes it possible to replace the gap forming member 97, the gap G can be easily adjusted by preparing a plurality of types of gap forming members 97 having different thicknesses.

  The pair of gap forming members 97 is in a semi-fixed state. Thus, the position and posture of the pair of gap forming members 97 are appropriately adjusted autonomously with the rotation of the fixing belt 92A. This eliminates the need for fine adjustment of the attachment positions of the pair of gap forming members 97 and improves assemblability.

  In the separation member 95, the gap forming member 97 has a surface layer 97B made of a fluorine-based resin. Since it did in this way, abrasion of the contact part with the fixing belt 92A in the gap formation member 97 can be reduced, and durability can be improved.

  In the separating member 95, the gap forming member 97 is formed in a rectangular shape in plan view. Thus, for example, when the gap forming member 97 is cut out and manufactured from a resin sheet-like base material, more gap forming members are formed from one base material than in a complicated shape. 97 can be cut out. Therefore, the gap forming member 97 can be manufactured easily and at low cost.

  The gap forming member 97 is disposed so as to be in contact with the outside of the fixing region on the outer peripheral surface F of the fixing belt 92A. Thus, stress due to contact with the gap forming member 97 can be avoided in the fixing region of the fixing belt 92A, and the toner image can be stably fixed on the recording medium S.

(Embodiment of fixing device)
Hereinafter, a fixing device according to an embodiment of the present invention will be described with reference to FIG.

  FIG. 5 is a schematic configuration diagram of a fixing device according to an embodiment of the present invention.

  As shown in FIG. 5, the fixing device 9 includes a separator 91, a heating mechanism 92, and a pressure roller 93.

  The separator 91 separates the sheet-like recording medium S such as paper, recording paper, transfer paper, etc. from the heating mechanism 92 (specifically, the fixing belt 92A). A separating member 95 is used.

  The heating mechanism 92 includes a fixing belt 92A, a support member 92B, a nip forming member 92C, and a heat source 92D. The fixing belt 92A is formed in an endless belt shape using, for example, a flexible synthetic resin material. The support member 92B is disposed inside the fixing belt 92A and supports the fixing belt 92A so as to be rotatable. The nip forming member 92C is disposed at a position facing the pressure roller 93 in the support member 92B. When the pressure roller 93 is pressed against the nip forming member 92C via the fixing belt 92A, a fixing nip portion N is formed between the fixing belt 92A and the pressure roller 93. The heat source 92D is composed of, for example, a halogen heater, and is disposed inside the rotation locus of the fixing belt 92A. The fixing belt 92A corresponds to an example of a fixing rotating body.

  The pressure roller 93 is configured by laminating a silicone rubber layer on the surface of a hollow metal roller, and a surface layer portion is provided with a fluorine resin layer such as PFA or PTFE as a release layer. The pressure roller 93 is arranged so that its axis is parallel to the width direction of the fixing belt 92 </ b> A (front-back direction in FIG. 5). The pressure roller 93 is rotationally driven by a drive motor (not shown). Further, the pressure roller 93 is pressed toward the nip forming member 92C side (leftward in FIG. 5) by an elastic body such as a spring (not shown). The pressure roller 93 corresponds to an example of a pressure rotator.

  As described above, the separator 91, that is, the separation member 95 includes the separation plate 96 and the pair of gap forming members 97. The separation member 95 is disposed such that the separation plate 96 faces the outer peripheral surface F of the fixing belt 92 </ b> A and the one edge portion 96 g downstream of the fixing nip portion N (upward in FIG. 5). In addition, the pair of gap forming members 97 are arranged at one edge portion 96g so as to be sandwiched between a portion of both ends of one edge portion 96g of the separation plate 96 and the outer peripheral surface F of the fixing belt 92A. It is arranged across the direction intersecting with the extending direction. As a result, a gap G corresponding to the thickness of the pair of gap forming members 97 is formed between the portion between the pair of gap forming members 97 at one edge 96g of the separation plate 96 and the outer peripheral surface F of the fixing belt 92A. Is done.

  In the fixing device 9, the pressure roller 93 is pressed against the fixing belt 92 </ b> A at the fixing nip portion N. Therefore, when the pressure roller 93 is rotationally driven while being pressed toward the nip forming member 92C, the fixing belt 92A is rotated in conjunction with the pressure roller 93. As a result, the portion of the fixing belt 92 </ b> A heated by the heat source 92 </ b> D can be sequentially moved to the fixing nip portion N. As the fixing belt 92A and the pressure roller 93 rotate, the recording medium S entering the fixing nip portion N is nipped and conveyed between the fixing belt 92A and the pressure roller 93 in the fixing nip portion N. The toner image T is fixed on the recording medium S by being heated and pressurized. Then, the recording medium S that has passed through the fixing nip N is separated from the outer peripheral surface F of the fixing belt 92A by the separating member 95 and conveyed downstream of the fixing device 9.

  As described above, according to the fixing device 9 of the present embodiment, the fixing belt 92A for fixing the toner image T to the recording medium S is provided. The fixing device 9 includes a pressure roller that is pressed against the fixing belt 92A and forms a fixing nip portion N in which the recording medium S is sandwiched between the fixing belt 92A. The fixing device 9 includes a separator 91 that separates the recording medium S from the fixing belt 92A. And the separation body 91 is comprised by the separation member 95 of embodiment mentioned above. As a result, the gap forming member 97 of the separating member 95 is sandwiched between a part of both ends of the edge 96g of the separating plate 96 and the outer peripheral surface F of the fixing belt 92A. Then, the gap forming member 97 is located between a portion other than the above-mentioned part (that is, a portion between the pair of gap forming members 97) in the edge 96g of the separation plate 96 and the outer peripheral surface F of the fixing belt 92A. A gap G corresponding to the thickness is formed. Therefore, since the gap G is determined by the thickness of the gap forming member 97, it is possible to avoid the influence of many shape tolerances and mounting tolerances on the gap G, and to effectively suppress a decrease in the accuracy of the gap G. it can. Further, since the size of the gap G can be controlled by the thickness of the gap forming member 97, the size of the gap G can be easily adjusted.

(Embodiment of Image Forming Apparatus)
Next, an image forming apparatus 1 according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 6 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 7 is a schematic configuration diagram of a process cartridge provided in the image forming apparatus of FIG.

  An image forming apparatus 1 according to an embodiment of the present invention is used as a copying machine, a printer, a facsimile, or a complex machine thereof that fixes a toner image on a sheet-like recording medium S. In this embodiment, a tandem full-color image forming apparatus will be described. Alternatively, for example, a four-cycle full-color image forming apparatus may be used, and an image forming unit that forms a toner image on the recording medium S and a toner image formed on the recording medium S by the image forming unit are recorded on the recording medium S. The image forming apparatus may include at least a fixing unit that fixes the image forming apparatus.

  FIG. 6 shows the image forming apparatus 1. The image forming apparatus 1 includes an exposure device 3 that irradiates a laser beam L, a process unit 5 that forms an electrostatic latent image with the laser beam L and forms a toner image from the electrostatic latent image, and the process unit 5. And an intermediate transfer unit 7 to which the toner image is transferred. The image forming apparatus 1 also includes a secondary transfer unit 8 that transfers the toner image from the intermediate transfer unit 7 to the recording medium S, and the fixing device according to the above-described embodiment that fixes the transferred toner image to the recording medium S. 9. The image forming apparatus 1 also includes a stock tray 11 that temporarily holds a recording medium S on which a toner image is fixed, a paper feed tray 13 that stores a plurality of recording media S, and a toner bottle. A bottle housing portion 43. In the image forming apparatus 1, the image forming unit 1 </ b> A is configured by the exposure device 3, the process unit 5, the intermediate transfer unit 7, and the secondary transfer unit 8. In the image forming apparatus 1, the fixing unit 9 is configured by the fixing device 9.

The exposure device 3 irradiates the surface of the photosensitive drum 15 charged by the charging device 17 described later with a laser beam L to form an electrostatic latent image corresponding to the image data. The exposure apparatus 3 includes a light source composed of a semiconductor laser that emits laser light L, an optical deflector that deflects the laser light L in the main scanning direction, and a photosensitive drum 15 that uses the deflected laser light L as a surface to be scanned. And an optical scanning optical system that collects light toward the surface.

  The process unit 5 is a process for charging the surface of the photoconductive drum 15, a process for developing a latent electrostatic image on the surface of the photoconductive drum 15 to form a toner image, and a transfer residual toner on the surface of the photoconductive drum 15 is removed. The process is repeated in sequence.

  The process unit 5 applies toner images of yellow, cyan, magenta, and black (hereinafter, “Y”, “C”, “M”, and “K” are attached to members corresponding to the respective colors). Process cartridges 10Y, 10M, 10C, and 10K for generation are provided.

  Each of the process cartridges 10Y, 10M, 10C, and 10K is configured to be detachable from the main body of the image forming apparatus 1, and the corresponding process cartridge can be replaced when the life is reached or exhausted. Yes.

  As shown in FIG. 7, the process cartridge 10Y includes a photosensitive drum 15Y on which an electrostatic latent image is formed by the laser light L emitted from the exposure device 3, a charging device 17Y for charging the photosensitive drum 15Y, It has. The process cartridge 10Y includes a developing device 19Y that develops the electrostatic latent image to form a toner image, and a cleaning device 21Y that cleans the surface of the photosensitive drum 15Y. The process cartridge 10Y contains yellow toner corresponding to the color separation component of the color image.

  The process cartridges 10M, 10C, and 10K have the same configuration as the process cartridge 10Y described above. The process cartridge 10M contains magenta toner corresponding to the color separation component of the color image. The process cartridge 10C contains cyan toner corresponding to the color separation component of the color image. The process cartridge 10K contains black toner corresponding to the color separation component of the color image.

  The photoconductor drum 15 is made of an aluminum base tube formed in a cylindrical shape, and an organic photoconductor layer is provided on the outer peripheral surface of the aluminum base tube. On the photosensitive drum 15, an electrostatic latent image is formed on the organic photosensitive layer by the laser light L scanned according to the image forming signal, and a toner image as an unfixed image is formed by toner of the developing device 19 described later. It is formed.

  The organic photoreceptor layer has an undercoat layer coated on the outer peripheral surface of the aluminum base tube. The organic photoreceptor layer has a charge generation layer that generates a positive charge and a negative charge by photoelectric conversion. The organophotoreceptor layer has a charge transport layer that transports positive charges generated in the charge generation layer and neutralizes the negative charges charged on the surface, and an overcoat layer for improving durability. ing.

  The charging device 17 includes a charging member that uniformly charges the surface of the photosensitive drum 15 to a desired polarity and a desired potential by applying a charging bias. As the charging member, for example, a charging roller made of an elastic body, a scorotron charger having a wire electrode and a grid electrode, or the like can be used.

  The developing device 19 performs development by attaching toner to the electrostatic latent image formed on the surface of the photosensitive drum 15. The developing device 19 includes a developing roller as a toner carrier. The developing roller is provided with a magnet roller as a magnetic field generating means. The developing roller rotates while carrying the toner on the surface thereof, thereby conveying the toner to a developing area facing the photosensitive drum 15.

  A developing bias is applied to the developing roller from a developing bias power source. For this reason, in the developing area, a potential difference is generated between the potential on the surface of the developing roller and the potential on the electrostatic latent image portion on the surface of the photosensitive drum 15, and is affected by the developing electric field formed by this potential difference. The toner adheres to the electrostatic latent image portion. As a result, the electrostatic latent image on the photosensitive drum 15 becomes a toner image as an unfixed image. The developing device 19 is not limited to such a configuration, and a known device can be used.

  The cleaning device 21 removes transfer residual toner remaining on the surface of the photosensitive drum 15 without being transferred to the intermediate transfer unit 7 described later from the surface of the photosensitive drum 15. The cleaning device 21 includes a blade member that scrapes off and removes transfer residual toner on the surface of the photosensitive drum 15.

  The blade member is made of a synthetic resin such as polyurethane resin, and is attached to the metal support of the cleaning device 21. The blade member is in a counter direction with respect to the rotation direction of the photosensitive drum 15 and is in contact with the surface of the photosensitive drum 15. In addition to the untransferred toner, the blade member includes paper dust of the recording medium S, discharge products when the photosensitive drum 15 is charged by the charging device 17, additives added to the toner, impurities contained in the toner, and the like. Are removed from the surface of the photosensitive drum 15.

  The intermediate transfer unit 7 transfers the toner image on the surface of the photosensitive drum 15 to the surface of the recording medium S. The intermediate transfer unit 7 includes an endless intermediate transfer belt 27, and a cleaning backup roller 25 and a secondary transfer backup roller 12 on which the intermediate transfer belt 27 is stretched and around the intermediate transfer belt 27. . Further, the intermediate transfer unit 7 faces a plurality of photosensitive drums 15 corresponding to the respective colors, and a plurality of primary transfer rollers 29Y and 29M that press the intermediate transfer belt 27 against each of the plurality of photosensitive drums 15. 29C and 29K. In addition, the intermediate transfer unit 7 includes a belt cleaning device 33.

  The intermediate transfer belt 27 is rotated counterclockwise on the drawing while being held at a predetermined tension by the tension roller 35. The intermediate transfer belt 27 is made of, for example, a single layer or a plurality of layers of vinylidene fluoride resin, ethylene tetrafluoride-ethylene copolymer resin, polyimide (PI) resin, polycarbonate (PC) resin, and the like. A conductive material is dispersed.

  The primary transfer rollers 29Y, 29M, 29C, and 29K include a conductive material such as carbon black and are semiconductive. The primary transfer rollers 29Y, 29M, 29C, and 29K are biased with a polarity opposite to the polarity of the charge of the toner. Therefore, the toner is attracted from the surface of the photosensitive drum 15 to the intermediate transfer belt 27 side to primarily transfer the toner image to the intermediate transfer belt 27.

  The secondary transfer unit 8 includes a secondary transfer roller 31 that presses the recording medium S against the intermediate transfer belt 27. The secondary transfer roller 31 is provided to face the secondary transfer backup roller 12.

  Similar to the primary transfer rollers 29Y, 29M, 29C, and 29K, the secondary transfer roller 31 includes a conductive material such as carbon black, is semiconductive, and has a polarity opposite to the polarity of the toner charge. A bias is applied. Therefore, the toner is attracted from the surface of the intermediate transfer belt 27 toward the recording medium S, and the toner image is secondarily transferred to the recording medium S.

  The belt cleaning device 33 includes a cleaning blade made of an elastic material such as urethane rubber that contacts the intermediate transfer belt 27. The cleaning blade is detachably held by a swingable blade holder. The cleaning blade contacts the intermediate transfer belt 27 in the counter direction with respect to the circumferential direction of the intermediate transfer belt 27, and dams and removes transfer residual toner on the surface of the intermediate transfer belt 27.

  For this reason, the cleaning blade removes paper powder of the recording medium S, additives added to the toner, impurities contained in the toner, and the like from the surface of the intermediate transfer belt 27 in addition to the transfer residual toner. The toner removed from the intermediate transfer belt 27 is collected by a toner collecting unit by a conveying unit provided in the belt cleaning device 33.

  The fixing device 9 heats and pressurizes a toner image as an unfixed image on the recording medium S to fix the toner image on the recording medium S. The fixing device 9 includes a heating mechanism 92 having a fixing belt 92A, and a pressure roller 93 that presses the fixing belt 92A and rotates the fixing belt 92A.

  The paper feed tray 13 is provided in the lower part of the image forming apparatus 1. The paper feed tray 13 contains a plurality of recording media S such as recording paper. The recording medium S is pulled out from the sheet feeding tray 13 one by one by the sheet feeding roller 37 and is conveyed along the sheet conveying path R formed in the image forming apparatus 1.

  The bottle housing part 43 is provided on the upper part of the image forming apparatus 1. The bottle storage portion 43 stores toner bottles 45Y, 45M, 45C, and 45K. The toner bottle 45Y is filled with yellow toner corresponding to the color separation component of the color image. The toner bottle 45M is filled with magenta toner corresponding to the color separation component of the color image. The toner bottle 45C is filled with cyan toner corresponding to the color separation component of the color image. The toner bottle 45K is filled with black toner corresponding to the color separation component of the color image.

  The toner of each color in each of the toner bottles 45Y, 45M, 45C, and 45K is appropriately supplied to each developing device 19 of each of the process cartridges 10Y, 10M, 10C, and 10K by a toner supply / delivery device (not shown). The toner bottles 45Y, 45M, 45C, and 45K are configured to be detachable from the image forming apparatus 1 independently of the process cartridges 10Y, 10M, 10C, and 10K.

  Next, the basic operation of the image forming apparatus 1 configured as described above will be described.

  When the image forming operation is started in the image forming apparatus 1, the photosensitive drums 15 of the process cartridges 10Y, 10M, 10C, and 10K are driven to rotate counterclockwise in the drawing. Then, the surface of each photosensitive drum 15 is uniformly charged to a predetermined polarity by each charging device 17.

  Next, the surface of each charged photosensitive drum 15 is irradiated with laser light L from the exposure device 3 to form an electrostatic latent image on the surface of each photosensitive drum 15. At this time, the image information exposed to each photosensitive drum 15 is single-color image information obtained by separating a desired full-color image into color information of yellow, magenta, cyan, and black.

  Next, toner is supplied to each electrostatic latent image on the surface of each photosensitive drum 15 by each developing device 19, and a toner image is formed from the electrostatic latent image. Further, a bias having a polarity opposite to the charging polarity of the toner is applied to each primary transfer roller 29Y, 29M, 29C, 29K. As a result, a transfer electric field is formed between each primary transfer roller 29Y, 29M, 29C, and 29K and each photosensitive drum 15. Then, the toner images at various places formed on the respective photoconductive drums 15 are sequentially superimposed and transferred onto the intermediate transfer belt 27 that rotates counterclockwise in the drawing by the transfer electric field. At this time, a full-color toner image is carried on the intermediate transfer belt 27.

  Next, transfer residual toner remaining on the surface of each photoconductive drum 15 after the toner image is transferred is removed from the surface of each photoconductive drum 15 by each cleaning device 21. Next, the surface of each photoconductive drum 15 is subjected to a static elimination action by a static elimination device (not shown), and the surface potential is initialized to prepare for the next image formation.

  Further, the sheet feeding roller 37 is rotated by the driving device 52, and one sheet of recording medium S is sent out from the sheet feeding tray 13 to the sheet conveying path R. The recording medium S sent to the paper transport path R is timed by a pair of registration rollers 39 and sent between the secondary transfer roller 31 and the secondary transfer backup roller 12 facing the secondary transfer roller 31. At this time, a transfer voltage having a polarity opposite to the charged polarity of the toner of the toner image on the intermediate transfer belt 27 is applied to the secondary transfer roller 31, thereby forming a transfer electric field.

  Next, the toner images on the intermediate transfer belt 27 are transferred onto the recording medium S all at once by the transfer electric field. Further, the transfer residual toner remaining on the surface of the intermediate transfer belt 27 after the transfer of the toner image is removed by the belt cleaning device 33.

  Next, the recording medium S to which the toner image has been transferred is conveyed to the fixing device 9, and heat and pressure are applied to the recording medium S at the fixing nip N between the fixing belt 92 </ b> A and the pressure roller 93. Thus, the toner image is fixed on the recording medium S. The recording medium S that has passed through the fixing nip N is separated from the outer peripheral surface F of the fixing belt 92A by the separating member 95, and then the recording medium S is discharged from the fixing device 9 to the stock tray 11.

  Such a basic operation of the image forming apparatus 1 is an image forming operation when a full-color image is formed on the recording medium S. In addition to this operation, a single-color image is formed using any one of the process cartridges 10Y, 10M, 10C, and 10K, or two or three colors are used using two or three process cartridges. A color image may be formed.

  As described above, according to the image forming apparatus 1 of the present embodiment, the image forming unit 1A that forms a toner image on the recording medium S and the toner image formed on the recording medium S by the image forming unit 1A are recorded on the recording medium S. A fixing unit 1B for fixing. The fixing unit 1B is composed of the fixing device 9 described above. As a result, in the fixing device 9, the gap forming member 97 of the separating member 95 is sandwiched between a part of both ends of the one edge portion 96 g of the separating plate 96 and the outer peripheral surface F of the fixing belt 92 </ b> A. Then, the gap forming member 97 is located between a portion other than the above-mentioned part (that is, a portion between the pair of gap forming members 97) in the edge 96g of the separation plate 96 and the outer peripheral surface F of the fixing belt 92A. A gap G corresponding to the thickness is formed. Therefore, since the gap G is determined by the thickness of the gap forming member 97, it is possible to avoid the influence of many shape tolerances and mounting tolerances on the gap G, and to effectively suppress a decrease in the accuracy of the gap G. it can. Further, since the size of the gap G can be controlled by the thickness of the gap forming member 97, the size of the gap G can be easily adjusted.

  Although the present invention has been described with reference to the preferred embodiment, the present invention is not limited to the configuration of the above embodiment.

  For example, in the above-described embodiment, the pair of gap forming members 97 are attached to the separation plate 96 in a semi-fixed state, but the present invention is not limited to this. For example, as shown in FIGS. 8A to 8C, instead of the gap forming member 97, a tape-like gap forming member 98 having an adhesive layer provided on one side thereof is separated from one surface 96 e of the separation plate 96. The separation member 95A may be configured to be pasted to the other surface 96f through the edge 96g. Even in such a configuration, the same effects as those of the above-described embodiment can be obtained. That is, when the gap forming member 98 is sandwiched between a part of the one edge part 96g and the outer peripheral surface F of the fixing belt 92A, the part other than the part part in the one edge part 96g of the separation plate 96 is fixed. A gap G corresponding to the thickness is formed between the outer peripheral surface F of the belt 92A. Therefore, since the gap G is determined by the thickness of the gap forming member 98, it is possible to avoid the influence of many shape tolerances and mounting tolerances on the gap G, and to effectively suppress a decrease in the accuracy of the gap G. it can.

  In the above-described embodiment, the pair of gap forming members 97 is in a semi-fixed state, but the present invention is not limited to this. The one end portion 97a of the gap forming member 97 may also be configured to be fixed to the separation plate 96 with screws or the like, similarly to the other end portion 97b. Alternatively, only one of the one end portion 97 a and the other end portion 97 b of the gap forming member 97 may be attached to the separation plate 96. Thereby, the edge part which is not attached to the separating plate of the gap formation member 97 becomes a free end. Even in such a configuration, when the fixing belt 92A is rotated in a state where the gap forming member 97 is sandwiched between a part of the one edge portion 96g and the outer peripheral surface F of the fixing belt 92A, the same as in the above embodiment. In addition, the position and posture of the gap forming member 97 are appropriately adjusted autonomously.

  Further, in the separation member 95 of the above-described embodiment, the gap forming member 97 has a configuration in which the surface layer 97B made of a fluororesin is provided on the entire surface of the base material 97A, but at least the fixing belt in the base material 97A. What is necessary is just to be provided in the location which touches 92A. In other words, at least the portion of the surface of the gap forming member 97 that contacts the outer peripheral surface F of the fixing belt 92A only needs to be made of a fluorine resin. In addition, if the base material 97A itself of the gap forming member 97 is, for example, PTFE or the like having a good sliding property and high durability, a layer made of a fluorine-based resin may not be provided on the surface. Further, although the gap forming member 97 is made of a resin material, it may be made of a thin-film stainless steel material, for example.

In the fixing device 9 of the above-described embodiment, the separation member 95 is provided so as to separate the recording medium S from the fixing belt 92A. However, the present invention is not limited to this. For example,
A separating member 95 may be provided so as to separate the recording medium S from the outer peripheral surface of the pressure roller 93.

  In the image forming apparatus 1 of the above-described embodiment, a full-color tandem type image forming apparatus in which a plurality of photoconductors are arranged in a line is described. However, the present invention is not limited to this. For example, it may be a monochrome image forming apparatus having only one photoconductor or a revolver type image forming apparatus, as long as it has at least an image forming part and a fixing part, as long as the object of the present invention is not violated. The configuration of the image forming apparatus is arbitrary.

  The above-described embodiments are merely representative examples of the present invention, and the present invention is not limited to the embodiments. That is, those skilled in the art can implement various modifications in accordance with conventionally known knowledge without departing from the scope of the present invention. Of course, such modifications are included in the scope of the present invention as long as the separation member, the fixing device, and the image forming apparatus of the present invention are provided.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 1A Image forming part 1B Fixing part 9 Fixing apparatus 91 Separator 92 Heating mechanism part 92A Fixing belt (an example of a fixing rotator)
92B support member 92C nip forming member 92D heat source 93 pressure roller (an example of a pressure rotator)
95, 95A Separation member 96 Separation plate 96a Separation plate body 96b A pair of support portions 96c Hooking claws 96d Screw holes 96e One surface of the separation plate 96f The other surface of the separation plate 96g One edge 97, 98 of the separation plate Gap forming member 97A Base material 97B Surface layer (an example of a part composed of a fluororesin)
97a One end of the gap forming member (an example of a part of the gap forming member)
97b The other end of the gap forming member (an example of another part of the gap forming member)
97c Claw receiving hole 97d Screw through hole 97e Intermediate part of gap forming member F Outer peripheral surface of fixing belt G Gap N Fixing nip S Recording medium T Toner image

JP 2006-317492 A JP 2009-109574 A

Claims (8)

A fixing rotator that fixes an unfixed image on a recording medium, and a pressure rotator that is in pressure contact with the fixing rotator and forms a fixing nip portion between which the recording medium is sandwiched. Separating member used in the fixing device,
A separation plate disposed downstream of the fixing nip so that an outer peripheral surface of the fixing rotator or an outer peripheral surface of the pressure rotator is opposed to one edge;
The one part extends to the one edge so as to be sandwiched between the one part of the one edge of the separation plate and the outer peripheral surface of the fixing rotator or the outer peripheral surface of the pressure rotator. A plate-shaped gap forming member arranged across the direction intersecting the direction;
With
The gap forming member is made of a flexible material,
A part of the gap forming member is attached to one surface of the separation plate,
The other part of the gap forming member spaced apart from the part is attached to the other surface of the separation plate,
Between the part and the other part of the gap forming member is arranged so as to be bent in a curved shape and cross over the part in a cross-sectional view in a direction orthogonal to the extending direction,
A portion of the gap forming member that spans the part of the separation plate is in contact with an outer peripheral surface of the fixing rotator or an outer peripheral surface of the pressure rotator, and the separation plate, the fixing rotator or A separation member configured to form a gap between the pressure rotating body and the pressure rotating body.   The separation member according to claim 1, wherein the gap between the separation plate and the fixing rotator or the pressure rotator is based on a thickness of the gap forming member.   The separation member according to claim 1, wherein the gap forming member is detachably attached to the separation plate.   4. The fluororesin is used as a material for at least a portion in contact with the outer peripheral surface of the fixing rotator or the outer peripheral surface of the pressure rotator on the surface of the gap forming member. The separation member according to any one of the above.   The separation member according to claim 1, wherein the gap forming member is formed in a rectangular shape in plan view.   6. The gap forming member is disposed so as to be in contact with an outer side of a fixing region on an outer peripheral surface of the fixing rotator or an outer peripheral surface of the pressurizing rotator. The separating member according to 1.   A fixing device comprising the separation member according to claim 1.   An image forming apparatus comprising the fixing device according to claim 7.

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