JP5017006B2 - Fixing apparatus, image forming apparatus, and sheet conveying apparatus - Google Patents

Description

  The present invention relates to a fixing device that fixes an image formed on a sheet surface to a sheet, an image forming apparatus including the fixing device, and a sheet conveying device.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a printer, a copier, a facsimile machine, or a multifunction machine in which these are functionally combined includes a fixing device for fixing a toner image formed on the transfer sheet surface to the transfer sheet. The fixing device includes a pair of fixing rollers including a heating roller for melting toner and a pressure roller in pressure contact with the heating roller. Further, there is known an image forming apparatus in which a fixing device including a separation claw whose tip edge is pressed against at least one surface of the fixing roller pair is mounted (for example, see Patent Documents 1 to 5).

  The separation claw is disposed on the downstream side in the sheet conveyance direction with respect to the fixing roller pair, and the sheet remains attached to the fixing roller pair by being pressed against one surface of the heating roller or the pressure roller. This is to prevent this.

The separation claw is fixed by bonding the rear end of the separation claw to a thin bracket or the like and fixing the thin bracket to the apparatus main body or a unit-shaped fixing device with a screw.
JP 2005-099676 A Japanese Patent Laid-Open No. 11-184300 JP 2002-082564 A Japanese Patent Laid-Open No. 06-032516 JP 2002-287554 A

  However, in the fixing device configured as described above, since the rear end of the separation claw is bonded and fixed to a thin bracket or the like, the separation claw adhesion work is required separately from the thin wall bracket installation work, In addition to the increase in the number of parts, the installation work becomes complicated, resulting in inferior versatility.

  Further, it is necessary to prepare a thin bracket for holding the separation claw according to the length, width, thickness, etc. of the separation claw. For this reason, since it is necessary to prepare a plurality of types of separation claws, thin brackets, etc. in correspondence with each type of fixing device, there is a problem that inventory management including a mold is very troublesome. It was.

  Further, when the separation claw is held by the thin bracket, the whole thin bracket must be replaced when the separation claw is replaced. For this reason, even if it is necessary to replace the separation claw during maintenance work, it is difficult to replace the separation claw on the spot. There was also a problem that it was inferior in versatility from the viewpoint of maintenance.

  An object of the present invention is to provide a fixing device, an image forming apparatus, and a sheet conveying apparatus that can reduce the number of parts and improve the versatility of a separation claw.

A fixing device according to one aspect of the present invention has a pair of rotating bodies that form a nip portion for fixing an image formed on a sheet surface to a sheet, a leading end portion, and a trailing end portion, and the rotation A separation claw having a tip edge of the tip side portion pressed against the surface of at least one rotating body of the pair of bodies, and a cylindrical shaft that supports the separation claw, the separation claw comprising the tip side portion wherein comprising a pivot point which is integrally formed between the rear end portion, said rear end portion have a possible spring adjustment pressure contact force of the tip edge and the separation pawl, plate member The plate-like member is formed on a body portion formed so that the front end side portion and the rear end side portion are linearly connected to each other, and on both sides of the body portion to form the rotation fulcrum. A side plate portion disposed, and the side plate portion includes a front end side portion and a rear end side portion. It has a predetermined length in the forming direction and is integrated with the main body portion at a local connecting portion, and the side plate portion is processed into a cylindrical shape according to the columnar shaft, thereby forming a bearing shape. are pivot point is formed, the columnar shaft into the bearing-shaped pivot point is through, it characterized in that.

According to this configuration, it is possible to adjust the pressing force of the front end edge to the surface of the rotating body by the spring property of the rear end side portion. Further, since the separation claw is not fixedly supported but supported by the rotation fulcrum, the number of parts can be reduced, the separation claw can be easily attached, and versatility is improved. be able to. Further, the separation claw is formed of a flat plate member, and the flat plate member forms a main body portion formed such that the front end side portion and the rear end side portion are linearly connected to each other, and the rotation fulcrum. Therefore, since the side plate portions disposed on both side portions of the main body portion are provided, the separation claws can be easily created using the flat plate-like member.

In the above structure, if that also has a spring property the distal end side portion, so that the spring force of the rear end portion can be transmitted effectively to the tip edge.

In the above configuration, the rear end portion, Ru can be assumed to have portions of different width and said distal portion. According to this configuration, the spring force of the rear end side portion can be adjusted by the width size of the rear end side portion.

In this case, the front end side portion has a first width overall except for the front end edge portion, and the rear end side portion is generally narrower than the first width or overall. Ru can be configured with a wide second width than said first width.

An image forming apparatus according to another aspect of the present invention includes an image forming unit that performs a transfer process of transferring a toner image to a sheet, a fixing unit that applies heat to the sheet and performs a fixing process of the toner image, wherein the fixing portion is, it characterized in that it comprises a structure of the fixing device.

A sheet conveying apparatus according to still another aspect of the present invention includes a conveying body having a rotating conveying surface capable of conveying a sheet in a close contact state, a leading end portion, and a trailing end portion, and the conveying member. wherein a separation claw tip edge of the distal portion to the conveying surface is pressed against a cylindrical shaft for supporting the separation pawl, wherein the separation claw, the rear end portion and the distal portion of the comprising a rotation fulcrum integrally formed between the rear end portion have a adjustable spring resistance pressure contact force of the tip edge, the separation claw is comprised of a flat member, said flat The member includes a main body portion formed such that the front end side portion and the rear end side portion are connected in a straight line, and side plate portions disposed on both sides of the main body portion to form the rotation fulcrum. The side plate portion has a predetermined length in a direction in which the front end side portion and the rear end side portion are connected. And is integrated with the main body portion at a local connecting portion, and the side plate portion is processed into a cylindrical shape according to the columnar shaft to form a bearing-like rotation fulcrum. cage, the columnar shaft into the bearing-shaped pivot point is through, it characterized in that.

In this case, the carrier is that it is a conveyor belt which circulates bridged between a plurality of rollers, or, the carrier is a this is a conveying roller which rotates around the axis is the preferred embodiment .

  According to the present invention, it is possible to provide a fixing device, an image forming apparatus, and a sheet conveying apparatus that can reduce the number of components and improve the versatility of the separation claw.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Overall configuration of MFP)
FIG. 1 is an explanatory diagram of a multifunction machine 1 (image forming apparatus) including a fixing device according to an embodiment of the present invention. In FIG. 1, a multifunction machine 1 is an image forming apparatus having functions of a copying machine, a printer, a scanner, a facsimile, and the like, to which a fixing device is applied.

  The multifunction machine 1 has a plurality of stages of sheet tray units 3, 4, 5 that can be pulled out from the front surface of the apparatus body 2, a manual feed tray 6 provided on the side of the apparatus body 2, and functions of a copying machine, a facsimile machine, and a scanner. An automatic document feeder (hereinafter referred to as “ADF”) 7 for reading a document by a scanner unit (not shown), a display screen 8 on which various setting conditions are displayed and a panel switch function, and a display And an operation unit 9 for performing operations other than the operation on the screen 8. The display screen 8 employs a panel switch type so that the setting change such as the enlargement / reduction ratio can be performed. The operation unit 9 includes a start switch, a mode selection switch, a clear switch, a numeric key switch, and the like.

  In addition, the apparatus main body 2 includes a conveyance path 11 that takes out transfer sheets (not shown) stored in the sheet tray units 3, 4, and 5 and conveys them toward the paper discharge tray 10. In the apparatus main body 2, a registration sensor 12, a registration roller pair 13, an image forming unit 14, and a fixing device 15 are arranged in order from the manual feed tray 6 in the conveyance path 11 toward the downstream side in the sheet conveyance direction. A branch path 16 branched from the transport path 11 is provided on the downstream side of the fixing device 15.

  Further, the apparatus body 2 is provided with a switchback path 17, a reverse path 18 and a reverse discharge path 19. The switchback path 17 is for switching the front and back of the transfer sheet transported in the branch path 16 (at the time of transport) in front and back in the transport direction of the transfer sheet. The reversing path 18 is a path for returning the transfer sheet after switching the front and rear in the transport direction by the switchback path 17 to the transport path 11 upstream of the registration sensor 12 when performing image forming processing on both sides of the transfer sheet. is there. The reverse discharge path 19 is a path for discharging the transfer sheet from the paper discharge tray 10 after the front and back of the transfer sheet after image formation has been switched by the switchback path 17.

  The image forming unit 14 includes a photosensitive drum 20 and a charging device 21, an exposure device 22, a developing device 23, a transfer device 24, a cleaning device 25, and the like disposed around the photosensitive drum 20.

Example 1
2 to 10 show the fixing device 15 according to the first embodiment. FIG. 2 is a perspective view of the fixing device as viewed from the bottom. FIG. 3 is a side sectional view of the fixing device 15. FIG. 5 is a perspective view of the separation claw 28 with the shaft 30 passing through, FIG. 6 is a developed perspective view of the separation claw 28, and FIGS. 7 to 9 are perspective views of modifications of the separation claw 28 in the first embodiment. FIG. 10 is a developed perspective view of another modification of the separation claw 28 in the first embodiment.

  As shown in FIGS. 2 and 3, the fixing device 15 includes a fixing roller 26 that forms a nip portion for fixing a toner image (described later) formed on the surface of the transfer sheet by the image forming unit 14, and the fixing roller 26. A pressure roller 27 that is pressed against the fixing roller 26 and presses the transfer sheet against the fixing roller 26 is included. Further, the fixing device 15 includes a plurality of separation claws 28 whose leading edges are in pressure contact with the surface of the fixing roller 26, and a case 29 that holds these in a united state.

  The fixing roller 26 is provided with a heating member such as a halogen heater 50 inside, whereby the surface of the fixing roller 26 is heated. As the material of the fixing roller 26, aluminum, iron, or the like is used. For the pressure roller 27, heat-resistant rubber or the like is used. The fixing roller 26 and the pressure roller 27 constitute a “rotor pair” in the claims. In this embodiment, the separation claw 28 is pressed against the fixing roller 26 of the pair of rotating members. An example is shown.

  In this embodiment, the separation claw 28 is formed of a processed product of a flat plate member having spring properties. As the flat plate member, for example, a metal plate such as stainless steel or phosphor bronze having a thickness of 0.03 to 0.1 mm can be used. Further, it is desirable that at least the contact surface side with the fixing roller 26 is subjected to a coating process by painting or sticking a fluororesin.

  As shown in FIG. 4, the separation claw 28 has a front end side portion 28a and a rear end side portion 28b, and a front end edge portion 281 that is pressed against the roller surface of the fixing roller 26 is formed on the front end side portion 28a. Yes. And between the front end side part 28a and the rear end side part 28b, the rotation fulcrum 28c integrally formed with these is provided. As shown in FIG. 5, the rotation fulcrum 28c is molded in a cylindrical shape and formed in a bearing shape. A shaft 30 held by the case 29 is passed through the rotation fulcrum 28c.

  FIG. 6 shows the shape of the flat plate member 28 ′ before the rotation fulcrum 28 c of the separation claw 28 shown in FIGS. 4 and 5 is molded. The flat plate member 28 ′ includes a main body portion 280 having a strip-shaped planar shape, and a pair of side plate portions 282 disposed on both side portions of the main body portion 280.

The main body part 280 and the side plate part 282 are separated by a slit processing part 284 except for a tie bar part 283. In other words, the side plate part 282 is integrally connected to the main body part 280 by the tie bar part 283 (local connection part). The tie bar portion 283 is generally provided at the center position in the longitudinal direction of the main body portion 280. The main body 280 has a form in which the front end side portion 28a and the rear end side portion 28b are linearly connected, and the tie bar portion 283 serves as a boundary portion between them.

  The tip edge portion 281 is formed by tapering the end portion of the tip side portion 28a. The leading edge 281 is brought into contact with the surface of the fixing roller 26 and comes into contact with a transfer sheet to be wound around the fixing roller 26 and peels off. At this time, the taper processing is provided, whereby the peelability of the transfer sheet from the fixing roller 26 can be improved. The taper processing of the leading edge portion 281, the formation of the slit processing portion 284, and the formation of the outer shape of the flat plate member 28 ′ are realized by a method of punching a metal flat plate using a punching blade and a die, for example. can do.

  The side plate portion 282 is formed into a hollow cylindrical shape by being wound in a roll shape along the forming direction of the slit processing portion 284, and serves as a rotation fulcrum 28c. For example, after winding the side plate portion 282 in a roll shape, fixing the cylindrical shape by spot welding the winding end is one of desirable forming methods.

  Since the front end side portion 28a and the rear end side portion 28b are flat plates each having a certain length, they have a spring property as a plate spring. That is, both the front end side portion 28a and the rear end side portion 28b have a spring property that can be curved and warped in the longitudinal direction of the main body portion 280 to restore a linear shape.

  As shown in FIG. 2, when the separation claw 28 is assembled to the case 29, it is supported by a shaft 30 held by the case 29. At this time, as shown in FIG. 3, the rear end edge portion 285 of the rear end portion 28 b is brought into contact with the support step portion 291 provided in the case 29. Here, the three points of the position where the leading edge 281 contacts the fixing roller 26, the position of the shaft 30, and the support position of the support step 291 are linear in a side view as is apparent from FIG. is not. That is, the support position of the support step 291 is set to a relatively high position with respect to the position of the shaft 30.

  For this reason, when the separation claw 28 is assembled so as to be supported by the shaft 30, the rear end portion 28b is bent and deformed to generate a spring force. The spring force of the rear end side portion 28b acts as a force that bends and deforms the front end side portion 28a via the rotation fulcrum 28c. As a result of this bending deformation, a spring force is generated at the tip end portion 28 a, and the tip edge 281 is pressed against the fixing roller 26. With such a mechanism, the pressure contact force of the front edge portion 281 to the surface of the fixing roller 26 can be adjusted by the spring property of the rear end portion 28b.

  This means that the pressure contact force of the front end edge 281 can be adjusted by adjusting the width of the rear end side portion 28b. That is, as illustrated in FIG. 6, the rear end side portion 28 b has a portion having a width different from that of the front end side portion 28 a as compared with the case where the front end side portion 28 a and the rear end side portion 28 b have the same width. By doing so, the pressure contact force of the tip edge portion 281 can be changed. Here, the “width” is a width in a direction in which the shaft 30 passes through the rotation fulcrum 28c.

  FIG. 7 shows an example in which the width (second width) of the rear end side portion 28b is entirely reduced compared to the width (first width) of the front end side portion 28a excluding the front end edge portion 281. Yes. On the other hand, FIG. 8 shows an example in which the width (second width) of the rear end side portion 28b is made wider than the width (first width) of the front end side portion 28a.

  Since the spring strength of the rear end side portion 28b can be adjusted by adjusting the width of the rear end side portion 28b in this way, the width of the rear end side portion 28b is adjusted by cutting at a work site such as during maintenance. Thus, it is possible to set the pressure contact force of the tip edge portion 281 on-site. When such adjustment is intended, it is desirable to set the width of the rear end side portion 28b as wide as possible in order to widen the adjustment range of the spring strength.

  FIG. 9 shows an example in which a notch portion 28d in which a part in the width direction is notched is provided in the rear end side portion 28b. Here, an example in which a rectangular cutout portion 28d is formed at a substantially intermediate position between the rotation fulcrum 28c and the edge of the rear end portion 28b is shown. The formation of the notch 28d can also adjust the spring strength of the rear end side portion 28b in the same manner as the width adjustment of the rear end side portion 28b shown in FIGS.

  The spring strength of the rear end side portion 28b can be adjusted by adjusting the cutout amount of the cutout portion 28d. When it is intended to set the pressure contact force of the leading edge 281 on site, it is desirable to print a plurality of notch lines 28e for adjusting the notch amount of the notch 28d as shown in FIG. This makes it easier to adjust the spring strength at a work site such as during maintenance.

(Example 2)
11 to 16 show a fixing device 15A according to the second embodiment, FIG. 11 is a perspective view of the fixing device 15A viewed from the bottom surface, FIG. 12 is a side sectional view of the fixing device 15A, and FIG. 14 and 16 to 16 are perspective views of modifications of the separation claw in the second embodiment.

  As shown in FIGS. 11 and 12, the fixing device 15 </ b> A fixes the toner sheet formed on the surface of the transfer sheet by the image forming unit 14 and presses the fixing roller 26 to fix the transfer sheet. There are provided a pressure roller 27 to be pressed against the roller 26, a plurality of separation claws 38 whose tip edges are in pressure contact with the surface of the fixing roller 26, and a case 39 for holding them in a united state.

  In this embodiment, the separation claw 38 is formed of a processed product of a flat plate member having spring properties. As the flat plate member, for example, a metal plate such as stainless steel or phosphor bronze having a thickness of 0.03 to 0.1 mm can be used. Further, it is desirable that at least the contact surface side with the fixing roller 26 is subjected to a coating process by painting or sticking a fluororesin.

  As shown in FIG. 13, the separation claw 38 has a front end side portion 38a and a rear end side portion 38b, and a front end edge portion 381 that is pressed against the roller surface of the fixing roller 26 is formed on the front end side portion 38a. Yes. And between the front end side part 38a and the rear end side part 38b, the bowl-shaped axis | shaft 38c integrally formed with these is provided. The shaft 38 c is engaged with a shaft hole 39 a formed in the case 39.

  In the separation claw 38, as in the first embodiment shown in FIG. 6, the front end side portion 38a and the rear end side portion 38b of the main body are linearly connected with the same width. The side plate portion (shaft 38c) having a predetermined protruding length in the orthogonal direction is different from that of the first embodiment in that it is integrated with the main body portion in the continuous direction. This side plate portion constitutes a rotation fulcrum as the shaft 38c without being processed.

  The manner of assembling the separation claw 38 to the case 39 is substantially the same as the manner shown in FIG. The shaft 38 c is engaged with the shaft hole 39 a of the case 39, and the rear end edge portion 385 of the rear end side portion 38 b is brought into contact with the support step portion 391 provided in the case 39. Here, as shown in FIG. 13, the three points of the position where the leading edge 381 contacts the fixing roller 26, the position of the shaft hole 39 a, and the support position of the support step 391 are not linear in a side view. The support position of the support step 391 is set at a relatively high position with respect to the position of the shaft hole 39a.

  For this reason, when the separation claw 38 is assembled so as to be supported by the shaft hole 39a, the rear end side portion 38b is bent and deformed to generate a spring force. The spring force of the rear end side portion 38b acts as a force that bends and deforms the front end side portion 38a via the shaft 38c. As a result of this deformation, a spring force is generated at the tip end portion 38 a, and the tip edge 381 is pressed against the fixing roller 26. With such a mechanism, the pressure contact force of the front edge portion 381 to the surface of the fixing roller 26 can be adjusted by the spring property of the rear end side portion 38b.

  Similar to the first embodiment, by adjusting the width of the rear end side portion 38b, the pressure contact force of the front end edge portion 381 can be adjusted. FIG. 14 shows an example in which the width of the rear end side portion 38b is entirely reduced compared to the width of the front end side portion 38a excluding the front end edge portion 381. On the other hand, FIG. 15 shows an example in which the width of the rear end side portion 38b is made wider overall than the width of the front end side portion 38a.

  A specific example of the size of the separation claw 38 shown in FIG. 15 in which the rear end side portion 38b is wider than the front end side portion 38a will be described. For example, the minimum width of the tapered portion of the leading edge 381 is 1.5 mm, the width of the leading edge 38 a is 3.0 mm, the width of the trailing edge 38 b is 5.0 mm, and the axis from the forefront of the leading edge 381 is the axis. The length to the center of 38c is 20.0 mm, and the length from the rearmost end of the rear end side portion 38b to the center of the shaft 38c is 15.0 mm.

  FIG. 16 is a perspective view showing a separation claw 48 according to another modification of the second embodiment. The separation claw 48 has a length in which the front end edge 481 of the front end side portion 48a extends over substantially the entire width of the fixing roller 26, and the rear end side portion 48b is integrally provided at a plurality of positions with respect to the front end side portion 48a. Yes. An integrally formed shaft 48c is provided on the side between the front end side portion 48a and the rear end side portion 48b.

(Image formation processing)
With reference to FIG. 1, the transfer sheet is fed out from the sheet tray units 3, 4, 5 or the manual feed tray 6 and is conveyed along the conveyance path 11 to the registration roller pair 13, and the leading end of the sheet is the registration roller pair 13. Butted against the nip.

  At this time, since the transfer sheet is fed by the sheet conveying roller until the registration roller pair 13 starts to rotate, it is buckled in the conveying path 11 (the front end side of the transfer sheet is partially curved and deformed). ), The slant feed is corrected by this buckling. Thereafter, at the timing when the image formed on the surface of the photosensitive drum 20 and the leading edge of the transfer sheet meet, rotation of the registration roller pair 13 is started, and the transfer sheet is transferred between the photosensitive drum 20 and the transfer device 24. Then, it is fed by the registration roller pair 13.

  In the image forming unit 14, the photosensitive drum 20 is rotationally driven at a predetermined process speed (circumferential speed) by a driving mechanism (not shown), and the surface thereof is uniformly charged to a predetermined polarity and potential by the charging device 21.

  An electrostatic latent image is formed on the surface of the charged photosensitive drum 20 by the exposure device 22. Here, for example, the exposure device 22 is connected by a communication line such as a network by a printer function, image data read by a scanner unit using an ADF 7 by a copying machine function, image data received through a telephone line by a facsimile function, or the like. Rasterization is performed based on image data output from a personal computer or the like.

  Further, the exposure device 22 irradiates the surface of the photosensitive drum 20 with laser light based on the rasterized information, and removes the charge of the laser light irradiated portion on the surface of the photosensitive drum 20 to electrostatically respond to the image information. A latent image is formed. The electrostatic latent image formed on the surface of the photosensitive drum 20 is developed as a toner image by electrostatically attaching a charged toner to the developing device 23. The toner image attached to the surface of the photosensitive drum 20 is transferred as a transfer image to the transfer sheet by the transfer device 24. After the toner image is transferred to the transfer sheet, the residual toner and the like are removed by the cleaning device 25 and the charge is removed for charging during the next image formation.

  Here, in the case of single-sided printing on the transfer sheet, the transfer sheet is sent to the fixing device 15 (15A) to fix the toner image. The transfer sheet sent out from the fixing device 15 (15A) is conveyed along the sheet discharge path while being peeled off by the separation claw 28 (38, 48), and is discharged onto the discharge tray 10 by the sheet discharge roller.

  In the case of duplex printing on the transfer sheet, the transfer sheet fed from the fixing device 15 is guided to the branch path 16. The transfer sheet guided to the branch path 16 is sent to the switchback path 17 from the front end side of the transfer sheet, and then sent from the switchback path 17 to the reversing path 18 with the rear end of the transfer sheet at the front end side. Thereby, the front and back of the transfer sheet are reversed.

  The transfer sheet whose front and back are reversed is returned from the reverse path 18 to the transport path 11. After that, as in the case of the above-described single-sided printing, the sheet is conveyed by the pair of sheet conveying roller and registration roller 13, and an image is formed on the other one side which is an unprinted side through the image forming unit 14 and the fixing device 15. Double-sided printing ends. Thereafter, the transfer sheet printed on both sides is conveyed as it is on the conveyance path 11 and is discharged onto the discharge tray 10.

  When the transfer sheet printed only on one side is discharged onto the discharge tray 10 with the front and back sides reversed, the transfer sheet discharged from the fixing device 15 is reversed via the branch path 16. Guided to path 18. Then, after the transfer sheet is sent from the leading end side to the switchback path 17, the transfer sheet is discharged onto the discharge tray 10 via the reverse discharge path 19 with the trailing end side of the transfer sheet being the leading end side.

  When an image-formed transfer sheet is discharged to the paper discharge tray 10 and there is no next image forming process, driving of each drive system is stopped after a predetermined time has elapsed since the trailing edge of the transfer sheet was detected by the registration sensor 12. The

  As described above, in the fixing device 15 (15A) according to the present embodiment, the rear end side portion of the separation claw 28 (38, 48) is directly bonded to the thin bracket or the like without directly attaching the case 29 (39). ) Is rotatably supported. Therefore, the number of parts can be reduced, and the attaching operation of the separation claw 28 (38, 48) at the time of assembling the multifunction machine 1 can be facilitated, and the versatility can be improved.

  Further, the separation claws 28 (38, 48) can be made common, and by making it possible to cope with the work site, it is possible to realize simplification of inventory management and the like.

  Further, since the separation claw 28 (38, 48) is directly supported by the case 29 (39) so as to be rotatable, even if the separation claw 28 (38, 48) is forced to be replaced during maintenance work. The separation claw 28 (38, 48) can be easily replaced on the spot. Therefore, versatility can be improved from the viewpoint of maintenance and the like.

(Modified Example)
The present invention includes the following modified embodiments.

[1] In the above embodiment, the multifunction device 1 has been described as an example of an image forming apparatus to which the fixing device 15 of the present invention is applied. Instead, the present invention can be applied to various dedicated machines such as a copying machine, a printer, and a facsimile machine.

[2] In the fixing device 15 (15A) of the above embodiment, the fixing roller 26 and the pressure roller 27 are used. In addition, as shown in FIG. 17, for example, a heating roller 32 provided with a heating member such as a halogen heater 50 is brought into contact with the surface of the fixing roller 26 to heat the surface of the fixing roller 26. It can also be applied to a fixing device. Of course, the present invention can also be applied to a fixing device employing an induction heating method.

[3] Further, as shown in FIG. 18, the heating roller 32 provided with a heating member such as a halogen heater 50 is disposed apart from the fixing roller 26 and the conductive belt 33 is connected to the fixing roller 26 and the heating roller 32. 19, a fixing device that is provided so as to be capable of rotational movement and conductively heating the surface of the fixing roller 26, or as shown in FIG. 19, a fixing belt 34 is used instead of the fixing roller 26. The present invention can also be applied to a fixing device in which a heating body 35 that contacts the wall surface is provided to directly heat the fixing belt 34.

[4] Further, as shown in FIG. 20, instead of the pressure roller 27 described above, a pressing unit 27A comprising a pair of rollers 271, 272 and a pressing endless belt 273 spanned between them is used. The present invention may be applied to a conventional fixing device. Alternatively, as shown in FIG. 21, it can be applied to a fixing device using a pressing unit 27 </ b> B including a pressing endless belt 274 and a pressing pad 275 instead of the pressing roller 27.

[5] In the above embodiment, an example in which the present invention is applied to a fixing device has been described. In addition to this, the present invention is applicable to various sheet conveying apparatuses. For example, FIG. 22 shows a sheet conveying apparatus in an image forming unit of a tandem type color printer. The image forming unit includes an image forming unit of each color including a yellow unit 14Y, a magenta unit 14M, a cyan unit 14C, and a black unit 14K arranged in tandem, and a photosensitive drum (20K) of each unit and a transfer unit. And a conveyor belt 141 that circulates between the rollers (24K).

  The conveying belt 141 is stretched between a plurality of rollers 142, 143, and 144, and conveys the sheet P by electrostatically adsorbing the sheet P to the outer peripheral surface thereof. The toner image of each color formed by the image forming unit of each color is sequentially overcoated on the sheet P. Thereafter, the sheet P on which the color toner image is formed is guided to the nip portion between the fixing roller 26 and the pressure roller 27 and subjected to a fixing process.

  The separation claw 28 is pressed against the outer peripheral surface of the conveyance belt 141 at a position on the inlet side of the fixing roller pair. The separation claw 28 here functions to separate the sheet P electrostatically attracted to the outer peripheral surface of the conveyor belt 141 and to reliably guide the sheet P to the pair of fixing rollers.

[6] FIG. 23 is an illustration of another sheet conveying apparatus, and shows a sheet conveying apparatus using a large-diameter conveying roller 145 that rotates about an axis 146. Here, the sheet P is conveyed in a close contact state along the outer peripheral surface of the conveying roller 145 so as to be turned 180 degrees. The separation claw 28 is in pressure contact with the outer peripheral surface of the conveying roller 145 on the sheet exit side.

  In such a sheet conveying apparatus, when a thin sheet P such as a thin sheet is conveyed, the sheet P is likely to be wound around the conveying roller 145. The separation claw 28 prevents such wrapping in advance and contributes to realizing smooth conveyance of the sheet P.

1 is a schematic sectional view of an image forming apparatus according to the present invention. FIG. 2 is a perspective view of the fixing device according to the first exemplary embodiment of the present invention as viewed from the bottom. 1 is a side sectional view of a fixing device according to a first exemplary embodiment. It is a perspective view of the separation claw of Example 1. It is a perspective view of the state where the axis was made to penetrate the separation claw of Example 1. FIG. 3 is a developed perspective view of a separation claw of Example 1. It is a perspective view of the modification of the separation nail in Example 1. FIG. It is a perspective view of the modification of the separation nail in Example 1. FIG. It is a perspective view of the modification of the separation nail in Example 1. FIG. It is an expansion | deployment perspective view of the other modification of the separation nail | claw in Example 1. FIG. It is the perspective view which looked at the fixing device which concerns on Example 2 of this invention from the bottom face direction. 5 is a side sectional view of a fixing device according to Embodiment 2. FIG. It is a perspective view of the separation claw of Example 2. It is a perspective view of the modification of the separation nail in Example 2. It is a perspective view of the modification of the separation nail in Example 2. It is a perspective view of the modification of the separation nail in Example 2. It is explanatory drawing of the other fixing apparatus which concerns on this invention. It is explanatory drawing of the other fixing apparatus which concerns on this invention. It is explanatory drawing of the other fixing apparatus which concerns on this invention. It is explanatory drawing of the other fixing apparatus which concerns on this invention. It is explanatory drawing of the other fixing apparatus which concerns on this invention. It is explanatory drawing which shows simply embodiment of the sheet conveying apparatus which concerns on this invention. It is explanatory drawing which shows simply embodiment of the sheet conveying apparatus which concerns on this invention.

1 MFP (image forming device)
15 Fixing device 26 Heating roller (one of a pair of rotating bodies)
27 Pressure roller (one of a pair of rotating bodies)
28 Separation claw 28a Front end side portion 28b Rear end side portion 28c Rotating fulcrum

Claims (8)

A pair of rotating bodies that form a nip for fixing an image formed on the sheet surface to the sheet;
A separation claw having a front end side portion and a rear end side portion, wherein the front end edge of the front end side portion is pressed against at least one rotary body surface of the pair of rotary bodies;
A cylindrical shaft that supports the separation claw , and
The separation pawl has a rotation fulcrum integrally formed between the distal end portion and the rear end portion, said rear end portion have a adjustable spring resistance pressure contact force of the tip edge ,
The separation claw is composed of a flat plate member,
The flat plate member is disposed on both sides of the main body portion to form a main body portion formed so that the front end side portion and the rear end side portion are linearly connected to each other, and the rotation fulcrum. A side plate,
The side plate portion has a predetermined length in the connecting direction of the front end side portion and the rear end side portion, and is integrated with the main body portion at a local connecting portion, and the side plate portion is formed in the columnar shape. A bearing-shaped rotation fulcrum is formed by being processed into a cylindrical shape according to the axis of the shaft, and the columnar shaft is passed through the bearing-shaped rotation fulcrum.
A fixing device.   The fixing device according to claim 1, wherein the tip side portion also has a spring property. The fixing device according to claim 1 , wherein the rear end side portion has a portion having a width different from that of the front end side portion. The tip side portion has a first width overall except for the tip edge portion;
4. The fixing device according to claim 3 , wherein the rear end side portion has a second width that is generally smaller than the first width or wider than the first width as a whole. . An image forming unit that performs a transfer process for transferring a toner image to a sheet;
A fixing unit that applies heat to the sheet to perform fixing processing of the toner image,
The image forming apparatus, wherein the fixing unit includes the configuration of the fixing device according to claim 1 . A transport body having a rotating transport surface capable of transporting a sheet in a close contact state;
A separation claw having a front end side portion and a rear end side portion, and a front end edge of the front end side portion being pressed against the transport surface of the transport body;
A columnar shaft that supports the separation claw , and
The separation pawl has a rotation fulcrum integrally formed between the distal end portion and the rear end portion, said rear end portion have a possible spring adjustment pressure contact force of the tip edge ,
The separation claw is composed of a flat plate member,
The flat plate member is disposed on both sides of the main body portion to form a main body portion formed so that the front end side portion and the rear end side portion are linearly connected to each other, and the rotation fulcrum. A side plate,
The side plate portion has a predetermined length in the connecting direction of the front end side portion and the rear end side portion, and is integrated with the main body portion at a local connecting portion, and the side plate portion is formed in the columnar shape. A bearing-shaped rotation fulcrum is formed by being processed into a cylindrical shape according to the axis of the shaft, and the columnar shaft is passed through the bearing-shaped rotation fulcrum.
A sheet conveying apparatus. The sheet conveying apparatus according to claim 6 , wherein the conveying body is a conveying belt that is looped around a plurality of rollers. The sheet conveying apparatus according to claim 6 , wherein the conveying body is a conveying roller that rotates about an axis.

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