JP6068092B2 - Fixing apparatus and image forming apparatus having the same - Google Patents

Description

  In the present invention, a toner image formed on a recording paper such as plain paper or photosensitive paper by an electrophotographic method, an electrostatic recording method, or a magnetic photographic method is used at a nip portion of a pair of rotating members that are pressed against each other. The present invention relates to a fixing device for fixing to a recording paper by heating or pressurization, and an image forming apparatus having the fixing device, and in particular, a peeling plate for peeling the recording paper attached to the rotating body after passing through the nip portion from the rotating body. And an image forming apparatus including the same.

  In an image forming apparatus such as a copying machine, a recording sheet is pulled out from a paper feed tray and conveyed to an image forming unit, and an image is formed (printed) on the surface of the recording sheet. For example, when an electrophotographic system is used, a toner image carried on a photosensitive drum or a transfer body is transferred onto a conveyed recording paper, and then heated and pressed to fix the image on the recording paper.

  In the fixing unit, the toner image transferred onto the recording paper is fixed using a roller used for conveying the recording paper. For example, the fixing roller is heated and pressed at a predetermined nip so that the toner is welded and fixed to the recording paper. At this time, the surface of the recording paper on which the toner is formed and the surface of the fixing roller are brought into close contact with each other due to the fused toner, and the recording paper is hardly peeled off. For this reason, a peeling plate for peeling the recording paper from the fixing roller is provided.

  At this time, in consideration of the thickness of the recording paper to be image-formed, an appropriate gap is ensured between the front end of the fixing roller and the front end portion that contacts the recording paper and peels off the recording paper. It is important that the gap is maintained. If the gap is large, the recording paper is not peeled off and enters the gap between the roller and the peeling plate, resulting in a jam. On the other hand, if the tip of the release plate contacts the surface of the fixing roller, the surface of the fixing roller is scratched or rubbed, and the fixed image is adversely affected.

  Regarding a technique for making the gap between the peeling plate and the fixing member constant, for example, in Patent Document 1 below, a peeling guide for holding the peeling plate is brought into contact with the fixing roller, and the tip of the peeling plate and the surface of the fixing roller are A technique for ensuring the gap is disclosed.

  Further, in Patent Document 2 below, a contact member formed by a member different from the release plate is attached to both ends of the front end portion of the release plate, and the contact member is brought into contact with the surface of the fixing roller. A technique for ensuring a gap between the front end of the plate and the surface of the fixing roller is disclosed.

  Patent Document 3 below discloses a technique in which a contact member that comes into contact with the fixing belt is provided on the support member, the positional relationship between the support plate and the fixing belt is ensured, and then the release plate is adjusted with an adjusting screw. It is disclosed.

JP 2003-263064 A JP 2005-173447 A JP 2010-197920 A

  However, depending on the techniques disclosed in Patent Documents 1 and 2, a gap can be formed between the peeling plate and the surface of the fixing roller. However, since folding or another part is involved, the leading edge of the peeling plate and the fixing are fixed. It is not easy to make the gap with the member surface constant.

  In the technique disclosed in Patent Document 3, it is possible to make the gap constant, but there is a problem that the structure is complicated and the assembling time becomes long. Further, since adjustment is required, it takes time, and there is a problem that the total manufacturing time becomes long.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a fixing device and an image forming apparatus including the fixing device that can set the gap between the leading edge of the peeling plate and the surface of the fixing roller to an appropriate size without adjustment after assembly. And

  The above object can be achieved by the following.

  That is, the fixing device according to the present invention is a fixing device that fixes a toner image formed on a recording paper to the recording paper. The fixing device includes a pressure roller and a fixing member that is pressed against the surface of the pressure roller and sandwiches the recording paper between the pressure roller and conveys the recording paper in a conveyance direction orthogonal to the rotation axis of the pressure roller. A separation member that is disposed in the vicinity of the fixing member on the downstream side in the transport direction and separates the recording paper that is transported, and a contact member that is attached to both ends of the separation member and can contact the surface of the fixing member, The peeling member and the contact member are disposed so as to be rotatable around one axis parallel to the common side line of the surface of the fixing member and the surface of the pressure roller. The peeling member is disposed on the surface of the fixing member. In a state of being in contact with each other, a front end portion that is disposed at a predetermined interval from the surface of the fixing member and that contacts the recording paper to be conveyed and peels off the recording paper is provided.

  The contact member includes support members that respectively support both end portions of the peeling member so that the rotation axis of the contact member and the rotation axis of the peeling member coincide with each other.

  The contact member includes a plurality of support members, and the plurality of support members allow the contact member to be attached to the end of the peeling member in a direction perpendicular to the rotation axis of the peeling member.

  The contact member is composed of two members, and the two members have the same shape, and are attached to both ends of the peeling member in a translationally symmetrical arrangement.

  The fixing device further includes an urging member that applies a force to the peeling member so that the peeling member rotates around the axis and the front end portion approaches the surface of the fixing member. The contact member is brought into contact with the surface of the fixing member under the force of.

  The peeling member includes a base member including both ends, and a plate-shaped peeling plate that is fixed to the central portion of the base member and includes the tip.

  The fixing device further includes a frame that supports the fixing member and the pressure roller, and the frame includes a member that forms one shaft on which the peeling member and the contact member rotate.

  The portion of the contact member that contacts the surface of the fixing member has a smooth convex shape.

  An image forming apparatus according to the present invention includes the above-described fixing device. After the toner image formed on the recording paper is fixed by the fixing device, the recording paper is peeled off from the fixing member.

  According to the present invention, when a peeling member and a fixing member (fixing roller or fixing belt) are attached to the fixing device, a predetermined gap is automatically formed between the leading end of the peeling member and the surface of the fixing member. The Therefore, the time for adjusting the gap after mounting the peeling member becomes unnecessary, and the manufacturing time can be shortened.

  By using the same shape as the contact member (holder) to be mounted on both ends of the peeling member, the contact member can be manufactured with one mold, so that it can be manufactured with high dimensional accuracy and assembled. Sometimes parts are not confused.

  For fixing the peeling member to the base member, welding or the like can be adopted instead of using a screw or the like, adjustment at the assembly stage is unnecessary, and manufacturing time can be shortened.

  By forming the portion of the contact member in contact with the surface of the fixing member into a smooth convex shape, the surface of the fixing member is not damaged. In addition, since the size of the contact portion can be accurately adjusted simply by cutting the corresponding portion of the mold for forming the contact member, the gap between the tip of the peeling member and the surface of the fixing member is increased. It can be set with accuracy (for example, 0.4 mm).

1 is a perspective view showing an image forming apparatus according to an embodiment of the present invention. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. It is a top view which shows a fixing roller and a pressure roller. FIG. 3 is a plan view showing a fixing belt type fixing mechanism. FIG. 3 is a perspective view showing a peeling portion equipped in the image forming apparatus according to the embodiment of the present invention. FIG. 6 is a trihedral view showing the peeling portion shown in FIG. 5. It is the perspective view seen from the base part of the peeling part shown in FIG. 5, and the back surface of a peeling board. It is a right view which shows the peeling part shown in FIG. It is a right view which shows the assembly method of the peeling part shown in FIG. It is sectional drawing along the AA line of the peeling part shown in FIG. It is sectional drawing along the BB line of the peeling part shown in FIG. It is sectional drawing along CC line of the peeling part shown in FIG. FIG. 6 is a side view showing a mutual positional relationship among a peeling portion, a fixing roller, and a pressure roller shown in FIG. 5. FIG. 6 is a side view showing a contact portion of the peeling portion shown in FIG. 5 with the surface of the fixing roller. FIG. 6 is a three-side view illustrating a frame on which the peeling unit and the fixing roller illustrated in FIG. 5 are mounted. FIG. 6 is a perspective view illustrating a state where the peeling unit and the fixing roller illustrated in FIG. 5 are mounted on a frame. It is a top view which shows the method of mounting | wearing the flame | frame with the peeling part shown in FIG. FIG. 6 is a plan view showing a state in which the peeling portion shown in FIG. 5 is attached to a frame. It is a perspective view which shows the state in which the 1st holder and the urging | biasing part were attached to the 1st end part of the base member. FIG. 6 is a side view showing a state in which the first end is urged by the urging portion and the first holder shown in FIG. 5 is in contact with the surface of the fixing roller. It is a fragmentary sectional view which shows the 1st holder provided with a 1st edge part provided with a convex part around a hole, and a recessed part around a hole. It is a fragmentary sectional view which shows the fixing | fixed part formed in the 1st end part, the 1st holder, and the upper surface of a flame | frame in case a 1st end part is provided with a boss instead of a hole.

  In the following embodiments, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  An image forming apparatus according to an embodiment of the present invention has a copying function for reading an original and forming an image on a recording sheet (hereinafter also referred to as printing). Referring to FIG. 1, an image forming apparatus 100 according to an embodiment of the present invention includes an image reading unit 110, an automatic document feeder (ADF) 120 disposed above the image reading unit 110, and an image reading unit 110. An image forming unit 130, a paper feeding unit 140, a paper discharge tray 150, and an operation unit 160 are provided below.

  With reference to FIG. 2, each part constituting the image forming apparatus 100 will be described. Image data handled in the image forming apparatus 100 is separated into color image data using each color of black (K), cyan (C), magenta (M), and yellow (Y), that is, these four color components. Image data. Accordingly, the image forming unit 130 is provided with four each of the developing device 2, the photosensitive drum 3, the charger 5, and the cleaner unit 4 so as to form four types of latent images corresponding to the respective colors. Yes.

  The charger 5 is a device for uniformly charging the surface of the photosensitive drum 3 to a predetermined potential. The optical scanning device 1 is a laser scanning unit (LSU) provided with a laser emitting unit, a reflection mirror, and the like. The optical scanning device 1 exposes the charged photosensitive drum 3 according to input image data, thereby forming an electrostatic latent image according to the image data on the surface thereof. The developing device 2 visualizes the electrostatic latent images formed on the respective photosensitive drums 3 with toner of four colors (YMCK). The cleaner unit 4 removes and collects toner remaining on the surface of the photosensitive drum 3 after development and image transfer.

  The intermediate transfer belt unit 6 disposed above the photosensitive drum 3 includes an intermediate transfer belt 61, an intermediate transfer belt driving roller 62, an intermediate transfer belt driven roller 63, an intermediate transfer roller 64, and an intermediate transfer belt cleaning unit 65. I have. The intermediate transfer belt driving roller 62, the intermediate transfer belt driven roller 63, and the intermediate transfer roller 64 are driven to rotate while the intermediate transfer belt 61 is stretched.

  A color toner image (multicolor toner image) is formed on the intermediate transfer belt 61 by sequentially superimposing and transferring the respective color toner images formed on the photosensitive drum 3 onto the intermediate transfer belt 61. The toner image is transferred from the photosensitive drum 3 to the intermediate transfer belt 61 by an intermediate transfer roller 64 that is in contact with the back side of the intermediate transfer belt 61. A high-voltage transfer bias is applied to the intermediate transfer roller 64 in order to transfer the toner image.

  The image information (toner density distribution) stacked on the intermediate transfer belt 61 is transferred onto the recording paper by the transfer roller 10 disposed at the contact position between the recording paper and the intermediate transfer belt 61 when the intermediate transfer belt 61 is rotated. Transcribed. At this time, the intermediate transfer belt 61 and the transfer roller 10 are pressed against each other at a predetermined nip, and a voltage for transferring the toner onto the recording paper is applied to the transfer roller 10. The toner remaining on the intermediate transfer belt 61 is removed and collected by the intermediate transfer belt cleaning unit 65.

  The paper feed cassette 81 is a tray for storing recording paper used for image formation. The paper discharge tray 150 is a tray for collecting printed recording sheets face down, that is, with the printing surface facing down. Inside the image forming apparatus 100, a recording paper transport path S is formed in a substantially vertical direction in order to send the recording paper in the paper feed cassette 81 to the paper discharge tray 150 via the transfer roller 10 and the fixing unit 170. ing. In order to feed the recording paper from the paper feed cassette 81, pickup rollers 11a and 11b are respectively arranged to guide the recording paper one by one to the recording paper transport path S. The transport rollers 12 a to 12 d are small rollers for promoting and assisting the transport of the recording paper, and a plurality of transport rollers 12 a to 12 d are provided along the recording paper transport path S. The registration roller 13 temporarily holds the recording paper conveyed through the recording paper conveyance path S. Then, the registration roller 13 conveys the recording paper to the transfer roller 10 at a timing at which the leading edge of the toner image on the photosensitive drum 3 coincides with the leading edge of the recording paper.

  The fixing unit 170 includes a fixing roller 172 and a pressure roller 174. The fixing roller 172 and the pressure roller 174 rotate with the recording paper interposed therebetween. As shown in FIG. 3, the fixing roller 172 includes a heater 176 therein, and melts the multicolor toner image transferred to the recording paper by thermocompression bonding the toner to the recording paper together with the pressure roller 174. It has a function of mixing and press-contacting and thermally fixing the recording paper.

  A peeling unit 200 is disposed in the vicinity of the fixing roller 172. Since the toner is formed on the surface of the conveyed recording paper on the fixing roller 172 side, the recording paper on which the toner is thermally fixed adheres to the fixing roller 172 and is difficult to peel off. The peeling unit 200 is for peeling the recording paper adhering to the surface of the fixing roller 172. Details of the peeling portion 200 will be described later.

  Regarding the thermal fixing of the toner to the recording paper, various configurations are possible other than using a fixing roller provided with a heater. For example, an external heating belt for heating the fixing roller from the outside may be provided.

  Further, instead of the fixing roller 172, a configuration using a fixing belt 900 as shown in FIG. The fixing belt 900 is an endless belt, is wound around the heating roller 910 and the roller 972, and rotates while being stretched. The heating roller 910 includes a heater 976 and heats the fixing belt 900. The fixing belt 900 rotates while being pressed against the pressure roller 974 by the roller 972, and the pressure roller 974 also rotates. With such a configuration, the fixing belt 900 and the pressure roller 974 are fixed by pressing the toner onto the recording paper while rotating with the recording paper interposed therebetween.

  Also in the case of such a fixing method including the fixing belt 900, a peeling portion can be disposed to peel off the recording paper attached to the fixing belt. In that case, the peeling unit is disposed in the vicinity of the fixing belt 900 on the downstream side of the conveyance path of the recording paper conveyed by the fixing belt 900 and the pressure roller 974. Note that a heater may be provided inside the pressure roller 974.

  When double-sided printing is requested, the conveyance roller 12b rotates reversely when the trailing edge of the recording paper that has finished single-sided printing and has passed through the fixing unit 170 as described above is gripped by the final conveyance roller 12b in the conveyance path. To do. As a result, the recording paper is guided to the transport rollers 12c and 12d. Thereafter, the recording paper is conveyed to the registration roller 13, printed on the back surface of the recording paper in the same manner as described above, and then discharged to the paper discharge tray 150.

  Hereinafter, the peeling unit 200 will be described in detail. With reference to FIGS. 5 to 8, the peeling portion 200 includes a peeling plate 202, a guide rib 204, a base portion 210, a first holder 230, and a second holder 232. The peeling plate 202 is fixed to the base portion 210 and constitutes a peeling member as a single body.

  The peeling plate 202 is a plate-like body having an L-shaped cross section (see FIG. 8), and is formed of a highly rigid metal, such as SUS (stainless steel). The reason why the metal having high rigidity is used is that the leading edge of the peeling plate 202 is preferably formed thinly so that the recording paper attached to the fixing roller 172 is peeled off at the leading edge. The guide rib 204 is for preventing the printing surface of the recording paper from coming into contact with the surface of the peeling plate 202 and being damaged.

  The base part 210 includes a central part 216, a first end part 212, and a second end part 214. The central part 216 has a flat plate shape, and a first end 212 and a second end 214 are formed at both ends of the central part 216. For example, the base portion 210 is formed by forming the central portion 216, the first end portion 212, and the second end portion 214 into a planar shape by punching a metal flat plate or the like, and then the first end portion 212 and the second end portion 214. Is bent 90 degrees with respect to the central portion 216.

  The peeling plate 202 is fixed to the central portion 216 by welding (spot welding) or caulking. When the peeling plate 202 is fixed to the central portion 216 by caulking, for example, a plurality of through holes may be formed at corresponding positions of the peeling plate 202 and the central portion 216 and then fixed by caulking around the through holes.

  Holes 218 and 220 into which bosses (projections) described later are inserted are formed in the first end 212 and the second end 214, respectively. Further, around the holes 218 and 220, burrings 222 and 224 protruding from the surfaces of the first end 212 and the second end 214 are formed. Due to the burrings 222 and 224, the first end 212 and the second end 214 are positioned substantially perpendicular to the axis of the boss, and smoothly rotate around the axis of the boss to suppress damage due to friction or the like. it can.

  The first end 212 and the second end 214 have the same shape, that is, a shape having translational symmetry along the longitudinal direction of the central portion 216. Accordingly, in the first end 212 and the second end 214, the holes 218 and 220 are formed at the same position, and the burrings 222 and 224 are arranged on the same side, that is, on the right side in the front view of FIG.

  The base part 210 should just be formed with the member which can maintain a predetermined | prescribed shape, and is not limited to a metal. The rigidity as that of the peeling plate 202 is not necessary, and it may be formed of a member thicker than the peeling plate 202.

  The first holder 230 and the second holder 232 are made of resin. The first holder 230 and the second holder 232 are formed by injection molding using, for example, polyphenylene sulfide resin. The first holder 230 accommodates the first end 212 of the base portion 210 (attached to the first end 212), and the second holder 232 accommodates the second end 214 of the base portion 210 (second Attached to the end 214). The first holder 230 and the second holder 232 have the same shape. That is, the first holder 230 and the second holder 232 attached to the first end 212 and the second end 214 are translationally symmetric along the longitudinal direction of the central portion 216. Therefore, the positional relationship between the first end 212 and the first holder 230 will be mainly described below. The positional relationship between the second end 214 and the second holder 232 is the same.

  As shown in FIG. 9, the first holder 230 is formed with a concave portion 240 in the center portion so as to accommodate the shape of the first end portion 212 so that the first end portion 212 can be accommodated. The mounting direction of the first holder 230 is indicated by a left-pointing arrow. Further, the first holder 230 has a first guard portion 234, a claw portion 242 formed on the first guard portion 234 (see FIG. 10), and a second guard portion so as not to be easily detached from the first end portion 212. 236 and a third guard portion 238 are formed.

  In the state where the first holder 230 is attached to the first end portion 212, as shown in FIG. 10, the first end portion 212 is positioned between the first guard portion 234 and the recess 240, and the claw portion 242 is , Enters a rectangular hole 228 formed in the first end 212. As shown in FIGS. 11 and 12, the first end portion 212 is located between the second guard portion 236 and the concave portion 240 and between the third guard portion 238 and the concave portion 240. Therefore, once the first holder 230 is attached to the first end 212, it cannot be easily removed. The interval between the recess 240 and the first guard part 234, the second guard part 236, and the third guard part 238 is formed slightly larger than the thickness of the first end part 212. Therefore, there is play between the first holder 230 and the first end 212 when the first holder 230 is attached to the first end 212 (between the first holder 230 and the first end 212). There is a gap). The hole 244 formed in the first holder 230 substantially coincides with the hole 218 of the first end 212 when the first holder 230 is attached to the first end 212 (see FIG. 8).

  As shown in FIG. 13, the peeling unit 200 is disposed in the fixing unit 170 so that a part thereof comes into contact with the surface of the fixing roller 172. In FIG. 13, the fixing roller 172 and the pressure roller 174 are disposed on the opposite side of FIG. 2. That is, FIG. 13 is a diagram showing the arrangement of the fixing roller 172 and the pressure roller 174 when viewed from the back surface of FIG.

  Referring to FIG. 14, the portion where the first end portion 212 contacts the fixing roller 172 (hereinafter referred to as the fixing roller contact portion) is a cylindrical side surface having a radius R (the direction of the cylindrical axis is the direction of the first end portion 212 It is formed perpendicular to the surface, that is, parallel to the longitudinal direction of the central portion 216. When an appropriate position of the fixing roller contact portion 246 is in contact with the fixing roller 172, a gap suitable for peeling of the recording paper is indicated between the front end of the peeling plate 202 and the fixing roller 172 (indicated by reference numeral G in FIG. 14). Form. Note that the fixing roller contact portion 246 is in contact with the surface of the fixing roller 172 at a position on the fixing roller 172 where the recording paper does not pass (position close to both ends of the fixing roller 172).

  In the fixing unit 170, the first end 212 and the first holder 230 pass through the hole 218 of the first end 212 and the hole 244 of the first holder 230 (more precisely, the boss passed through the holes 218 and 244). It is installed so as to be rotatable as a center. Therefore, the first holder 230 (first end portion 212) sets the distance L between the rotation shaft 178 of the fixing roller 172 and the hole 244 (hole 218) appropriately, thereby fixing the fixing roller contact portion 246 to the fixing roller 172. Can be brought into contact with the surface. Then, by finely adjusting the distance L, the gap between the tip of the peeling plate 202 and the fixing roller 172 can be adjusted.

  The position at which the fixing roller contact portion 246 is brought into contact with the surface of the fixing roller 172 is determined by setting the angle α shown in FIG. 13 while maintaining the distance L between the rotation shaft 178 of the fixing roller 172 and the hole 218. It can be adjusted by changing. If the angle α is reduced, the fixing roller contact portion 246 approaches the contact portion (nip portion) of the fixing roller 172 and the pressure roller 174, and the tip of the peeling plate 202 also approaches the nip portion while maintaining the gap. Accordingly, the distance L and the angle are determined in consideration of the arrangement of the pressure roller 174 and the fixing roller 172 and the contact point P on the surface of the target fixing roller 172 (or the position of the tip of the target peeling plate 202). α may be determined.

  As described above, since the first end 212 and the first holder 230 are rotatable around the boss, when the first end 212 (first holder 230) is urged, the point P Contact is maintained. Since there is play in the first end 212 and the first holder 230, as will be described later, a force is applied to the first end 212 to urge the first holder 230 to the first end 212 and the first end The fixing roller contact portion 246 of the holder 230 is brought into contact with the fixing roller 172. Thus, the position of the tip of the peeling plate 202 relative to the surface of the fixing roller 172 can be determined and maintained only by applying a force to the first end 212.

  Similarly, the second end 214 and the second holder 232 are arranged in the fixing unit 170. In this way, the first end 212 and the first holder 230 of the peeling unit 200, the second end 214 and the second holder 232 are arranged, and the first end 212 and the second end 214 are biased. As a result, the position of the linear tip of the peeling plate 202 relative to the surface of the fixing roller 172 (gap between the surface of the fixing roller 172 and the tip of the peeling plate 202) can be appropriately determined and maintained. .

  As described above, the frame 300 shown in FIG. 15 is used to arrange the peeling portion 200 with respect to the fixing roller 172 so that the predetermined gap G is formed. The frame 300 includes an upper surface 320, a right side surface 322, a left side surface 324, and a back surface 326. On the upper surface 320, notches 330 and 332 are formed on the left and right, and cylindrical first boss 302 and second boss 304 are formed in the vicinity of the notches 330 and 332. The axes of the first boss 302 and the second boss 304 coincide and are on one straight line. In the vicinity of the notches 330 and 332, urging portion fixing portions 306 and 308 for fixing one end of an urging portion described later are formed. The urging portion fixing portions 306 and 308 are each formed with a through hole. Fixing roller shaft mounting portions (notches) 310 and 312 on which the rotation shaft 178 of the fixing roller 172 is mounted are formed on the right side surface 322 and the left side surface 324.

  As shown in FIG. 16, the peeling unit 200 and the fixing roller 172 are attached to the frame 300. In FIG. 16, the fixing roller shaft fixing portion 314 is mounted, and the rotation shaft 178 of the fixing roller 172 is rotatably held. Thereby, as described above, the positions of the peeling portion 200 and the fixing roller 172 are determined, and the position of the linear tip of the peeling plate 202 with respect to the surface of the fixing roller 172 is appropriately determined.

  In order to attach the peeling part 200 to the frame 300, as shown by arrows in FIG. 17, after inserting the first end 212 and the second end 214 of the base part 210 into the notches 330 and 332 of the frame 300, The first boss 302 and the second boss 304 are inserted into the holes 218 and 220 of the first end 212 and the second end 214, respectively, by moving leftward. Thereby, as shown in FIG. 18, the peeling portion 200 can be attached to the frame 300.

  Referring to FIG. 19, biasing portion 400 that applies force to first end portion 212 has one end portion 402 mounted in a hole formed in biasing portion fixing portion 226 of first end portion 212. As shown in FIG. 20, the other end 404 is attached to the hole of the urging portion fixing portion 306 formed on the upper surface 320 of the frame 300. In FIG. 20, for the sake of convenience, the side of the frame 300 is not shown, and only the upper surface 320 is indicated by a broken line.

  When the urging unit 400 is extended from a free state (a state in which no force is received), a restoring force is generated in a direction in which the length is shortened by an internal stress. The urging unit 400 is formed of, for example, a spring (coil spring). The urging portion 400 is mounted between the urging portion fixing portions 226 and 306 in an extended state. As a result, the biasing portion fixing portion 226 of the first end portion 212 is attracted to the biasing portion fixing portion 306 of the frame 300. Since the first end portion 212 and the first holder 230 are mounted on the frame 300 so as to be rotatable around the first boss 302, the first end portion 212 is on the biasing portion fixing portion 306 side of the frame 300. The fixing roller contact portion 246 of the first holder 230 is urged against the surface of the fixing roller 172.

  Similarly, in the urging portion that applies a force to the second end portion 214, one end portion 402 is mounted in a hole formed in the urging portion fixing portion of the second end portion 214, and the other end portion 404 is disposed. The urging portion fixing portion 308 formed in the upper surface 320 of the frame 300 is attached to the hole. As a result, the second end portion 214 is attracted to the biasing portion fixing portion 308 side of the frame 300, and the fixing roller contact portion 246 of the second holder 232 is biased to the surface of the fixing roller 172. Accordingly, as described above, the position of the linear tip of the peeling plate 202 with respect to the surface of the fixing roller 172 can be appropriately determined and maintained.

  As described above, the first end 212 and the second end 214 at both ends of the base portion 210 together with the first holder 230 and the second holder 232 have a common shaft (the first boss 302 and the second boss 304, respectively). The first holder 230 and the second holder 232 are urged against the surface of the fixing roller 172 so that the first holder 230 and the second holder 232 (fixing roller contact) The portion 246) contacts the surface of the fixing roller 172, and the gap at the tip of the peeling plate 202 can be appropriately determined. The common axis is parallel to a common side line (a straight line parallel to the central axis of the cylinder on the side surface of the cylinder) common to the surface of the pressure roller 174 and the surface of the fixing roller 172, and the rotation axis of the fixing roller. , And the rotation axis of the pressure roller.

  In the present embodiment, since the peeling mechanism is configured as shown in FIGS. 5 to 20, the shapes of the base portion 210, the first holder 230, and the second holder 232 are appropriately designed in advance, and the base If the peeling plate 202 is fixed at an appropriate position of the portion 210, the peeling portion 200 and the fixing roller 172 are attached to the frame 300, and only the biasing portion 200 is urged without adjustment. The tip can be arranged at a predetermined position, and the gap between the tip of the peeling plate 202 and the surface of the fixing roller is determined.

  In order to appropriately determine the gap, the shape of the fixing roller contact portion 246, specifically, the radius R is important. If the radius R is large, the gap is large, and if the radius R is small, the gap is small. With the configuration of the peeling portion 200 described above, the shape (radius R) of the fixing roller contact portion 246 can be easily determined at the prototype stage. As described above, the first holder 230 and the second holder 232 are formed by resin injection molding using a predetermined mold. At this time, a portion (concave portion) for forming the fixing roller contact portion 246 of the mold is formed slightly small. That is, the radius of curvature of the concave portion of the mold is kept small. When the actually formed first holder 230 and second holder 232 are attached to the frame 300, the fixing roller contact portion 246 does not contact the fixing roller 172 because the fixing roller contact portion 246 is small. Contacts the surface of the fixing roller 172. After it is confirmed that the tip of the peeling plate 202 is in contact with the surface of the fixing roller 172, the concave portion of the mold is scraped to slightly increase the radius of curvature. Again, the first holder 230 and the second holder 232 are created by injection molding and mounted on the frame 300 to check the state of the gap. By repeating this operation, the shape of the fixing roller contact portion 246 that can form an appropriate gap (that is, the shape of the corresponding concave portion of the mold) can be accurately determined. Thus, once the shape of the fixing roller contact portion 246 (the shape of the mold) is determined, the release plate 202 of the release plate 202 is simply adjusted by attaching the release portion 200 to the frame 300 as described above. The tip can be disposed at an appropriate position with respect to the surface of the fixing roller 172, and the gap can be determined appropriately. The gap is set to 0.4 mm, for example.

  Although the peeling part 200 of the structure shown in FIGS. 5-20 was demonstrated above, it is not limited to this, A various change can be made. For example, the central portion 216, the first end portion 212, and the second end portion 214 constituting the base portion 210 may be formed individually and then fixed by welding or the like.

  The direction in which the peeling portion is attached to the frame 300 may be opposite to the left and right. That is, the first boss 302 and the second boss 304 shown in FIG. 15 may be disposed on the upper surface 320 of the frame 300 so that the tips are located on the left side. In that case, the position of the notch is also changed. Furthermore, it is preferable that the burrings formed on the first end 212 and the second end 214 of the base 210 are formed on opposite surfaces.

  Further, when the first end portion 212 and the second end portion 214 have a certain thickness (for example, the same thickness as the thickness of the boss), the burring may be omitted.

  In FIG. 9 and the like, the upper portions of the first holder 230 and the second holder 232 have an inclined curved surface and a protruding shape, but are not limited thereto. When the first holder 230 and the second holder 232 are disposed in the fixing unit 170, the shape may be any shape that does not interfere with (does not hit) the surroundings. The overall shape of the first holder 230 and the second holder 232 is as follows. Is optional.

  Similarly, the shapes of the first end 212 and the second end 214 are not limited to the shapes shown in FIG. The first end 212 and the second end 214 may have a shape that can be attached to the first holder 230 and the second holder 232, and may have any shape that does not interfere with the surroundings when arranged in the fixing unit 170. The overall shape of the first end 212 and the second end 214 is arbitrary.

  The surface shape of the fixing roller contact portion 246 is not limited to the shape of the side surface of the cylinder, but is preferably a smooth convex shape (a shape in which the first-order differential coefficient continuously increases or decreases). For example, the fixing roller contact portion 246 may be hemispherical.

  The 1st guard part 234, the 2nd guard part 236, and the 3rd guard part 238 are not limited to the arrangement | positioning and shape which were shown in FIGS. For example, if the perimeters of the first end 212 and the holes 218 and 220 of the first holder 230 are as shown in FIG. 21, the first guard part 234, the second guard part 236, and the third guard part 238 are It does not have to be. In FIG. 21, a convex portion 252 is formed around the hole 218 of the first end portion 212. A recess 248 is formed around the hole 244 of the first holder 230. The convex part 252 is accommodated in the concave part 248. The burring of the first end 212 is not shown. If the first end 212 and the first holder 230 have such a shape, the first holder 230 is temporarily attached to the first end 212 even if the first holder 230 does not include the first guard portion 234. Then, the first holder 230 is not easily detached from the first end portion 212. In addition, the first holder 230 may not include the second guard part 236 and the third guard part 238. In this case, the claw portion 242 of the first guard portion 234 and the rectangular hole 228 of the first end portion 212 may be omitted.

  In addition, a recess is formed around the hole 218 of the first end portion 212, and a protrusion is accommodated in the recess formed around the hole 218 of the first end portion 212 around the hole 244 of the first holder 230. A part may be formed.

  The first guard portion 234, the second guard portion 236, and the third guard portion 238 formed on the first holder 230 and the second holder 232 are easily detached from the first end portion 212 and the second end portion 214. This is to facilitate assembly. Therefore, the first guard part 234, the second guard part 236, and the third guard part 238 do not affect the gap at the tip of the peeling plate 202, and may not be necessary.

  Moreover, although the case where the 1st boss | hub part 212 and the 1st holder 230 were rotatably fixed by the 1st boss | hub 302 was demonstrated above, it is not limited to this. For example, as shown in FIG. 22, the first end portion 212 may include a boss 254, and a fixing portion 338 having a hole may be formed on the upper surface 320 of the frame 300 instead of the first boss 302. The bosses 254 of the first end portion 212 are fixed to each other by being inserted into the holes 244 of the first holder 230 and the holes of the fixing portion 338 formed on the upper surface 320 of the frame 300. The same applies to the second end 214.

  In FIG. 22, the first holder 230 may include coaxial bosses on both sides instead of the hole 244. In that case, the bosses on both sides of the first holder 230 are inserted into the holes 218 (see FIG. 9) of the first end portion 212 and the holes of the fixing portion 338 formed on the upper surface 320 of the frame 300, respectively. Are fixed to each other. The same applies to the second holder 232.

  As long as the frame 300 can set the positional relationship between the peeling portion 200 and the fixing roller 172 in the fixing unit 170, the overall shape of the frame 300 is arbitrary. The frame 300 may be formed by assembling a plurality of parts without being formed as a single body as shown in FIG. Further, the frame 300 may be one to which the pressure roller 174 can be attached.

  In the above description, the case where the urging portion 400 generates a restoring force in a direction in which the length is shortened due to internal stress has been described, but the present invention is not limited to this. For example, the position of the urging portion fixing portion 226 at the first end portion 212 is set such that the center of the hole 218 and the urging portion fixing portion 306 of the frame 300 when the first end portion 212 is attached to the frame 300. , A biasing portion that generates a restoring force in a direction in which the length increases due to internal stress can be used. In that case, the urging unit is mounted in a compressed state from a free state. As a result, the fixing roller contact portion 246 can be brought into contact with the surface of the fixing roller 172 with a predetermined force.

  Moreover, although the case where the urging | biasing part was a spring was demonstrated, it is not limited to this. The urging portion may be an elastic member other than a spring, such as rubber.

  Further, the mechanism for bringing the first holder 230 and the second holder 232 into contact with the surface of the fixing roller 172 is not limited to the above-described mechanism. Any mechanism that urges the base portion 210 may be used, and instead of urging each of the first end portion 212 and the second end portion 214, for example, between the central portion 216 of the base portion 210 and the upper surface 320 of the frame 300. The urging unit 400 may be disposed in Also in this case, when the central portion 216 is biased, the first holder 230 and the second holder 232 are brought into contact with the surface of the fixing roller 172 via the first end portion 212 and the second end portion 214. be able to.

  In the above description, the case where both end portions (first end portion 212 and second end portion 214) of the base portion 210 are accommodated in individual holders (first holder 230 and second holder 232) has been described. However, it is not limited to this. For example, an integrated holder including a portion corresponding to the first holder 230 and a portion corresponding to the second holder 232 may be used. Even in that case, there is a predetermined play between the portion corresponding to the first holder 230 and the first end 212 and between the portion corresponding to the second holder 232 and the second end 214. It is preferable. By doing so, the integral holder can be brought into contact with the surface of the fixing roller 172 by urging the base portion 210.

  In the above description, the fixing method using the fixing roller 172 and the pressure roller 174 has been described. However, the present invention is not limited to this. As shown in FIG. 4, the present invention can also be applied to a fixing method using a fixing belt instead of a fixing roller.

  The present invention has been described above by describing the embodiment. However, the above-described embodiment is an exemplification, and the present invention is not limited to the above-described embodiment, and is implemented with various modifications. be able to.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 110 Image reading part 120 Automatic document feeder 130 Image forming part 140 Paper feed part 150 Paper discharge tray 160 Operation part 170 Fixing unit 172 Fixing roller 174 Pressure roller 176 Heater 200 Peeling part 202 Peeling board 210 Base part 212 First end portion 214 Second end portion 216 Center portion 230 First holder 232 Second holder 246 Fixing roller contact portion 300 Frame 400 Energizing portion

Claims (6)

A fixing device for fixing a toner image formed on a recording paper to the recording paper,
A pressure roller;
A fixing member that is pressed against the surface of the pressure roller and conveys the recording paper between the pressure roller and a conveyance direction orthogonal to the rotation axis of the pressure roller;
A peeling member that is disposed in the vicinity of the fixing member on the downstream side in the transport direction and peels the transported recording paper;
A contact member that is attached to both ends of the peeling member and can contact the surface of the fixing member;
The peeling member and the contact member are arranged so as to be rotatable around one axis parallel to a common side line of the surface of the fixing member and the surface of the pressure roller,
The peeling member is arranged at a predetermined interval from the surface of the fixing member in a state where the contact member is in contact with the surface of the fixing member, and comes into contact with the conveyed recording paper so that the recording paper is With a tip to be peeled off ,
The contact member includes a plurality of support members,
The plurality of support members allow the contact member to be attached to an end portion of the peeling member in a direction perpendicular to the rotation axis of the peeling member . Wherein the support member such that said pivot axis of the contact member and the rotation axis of said release member is matched, according to claim 1, wherein the benzalkonium to support both ends of the release member, respectively Fixing device. The contact member is composed of two members,
Two of the members are the same shape, both ends of the release member, the fixing device according to claim 1 or 2, characterized in that it is mounted in a translational symmetry arrangement.   A fixing device for fixing a toner image formed on a recording paper to the recording paper,
  A pressure roller;
  A fixing member that is pressed against the surface of the pressure roller and conveys the recording paper between the pressure roller and a conveyance direction orthogonal to the rotation axis of the pressure roller;
  A peeling member that is disposed in the vicinity of the fixing member on the downstream side in the transport direction and peels the transported recording paper;
  A contact member that is attached to both ends of the peeling member and can contact the surface of the fixing member;
  The peeling member and the contact member are arranged so as to be rotatable around one axis parallel to a common side line of the surface of the fixing member and the surface of the pressure roller,
  The peeling member is arranged at a predetermined interval from the surface of the fixing member in a state where the contact member is in contact with the surface of the fixing member, and comes into contact with the conveyed recording paper so that the recording paper is With a tip to be peeled off,
  The contact member is composed of two members,
  The two fixing members have the same shape, and are attached to both end portions of the peeling member in a translationally symmetrical arrangement.   The said contact member is provided with the supporting member which each supports the both ends of the said peeling member so that the rotation axis of the said contact member and the rotation axis of the said peeling member may correspond. The fixing device described. A fixing device according to any one of claims 1 to 5 , comprising:
An image forming apparatus comprising: fixing a toner image formed on a recording paper by the fixing device; and then peeling the recording paper from the fixing member.

Images