JP2009116141A - Image heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image heating device capable of restraining a running belt from approaching one side and allowing a user to apply oil on the belt accurately. <P>SOLUTION: The image heating device has: an endless belt 13 and a heating roller 11 for heating the toner image on a seat therebetween, a roller 15 supporting the belt 13 from its inner side to run, a pad 18 bringing the belt into pressure-contact with the heating roller 11 by pressurizing it from the inner side of the belt 13, and an oil applying roller 16 supplying a lubricant onto an inner face of the belt. The oil applying roller 16 is made to abut on the roller 15 to supply the lubricant through the roller 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image heating apparatus having an endless belt that heats a sheet carrying a toner image while nipping and conveying the sheet at its press contact portion.

  In an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus, a toner image is formed on a sheet, and the image is formed by heating and pressurizing and fixing the toner image. As an image heating device used as such a fixing device, a roller fixing method in which a fixing nip is formed by pressing a pressure roller against a fixing roller having a heater therein to perform fixing is conventionally employed.

  By the way, in order to increase the glossiness of the image and increase the speed of image formation, it is preferable to lengthen the sheet nip passage time and sufficiently melt the toner. However, in the case of the roller fixing method, in order to achieve this, the roller diameter must be increased, and the fixing device becomes larger.

  Therefore, a belt fixing method has been proposed that can obtain a sufficient nip width (length in the sheet conveying direction) while achieving a reduction in size and speed of the apparatus as compared with the roller fixing method. In this belt fixing method, as shown in FIG. 9, a member that presses the sheet against the fixing roller 11 is constituted by a pressure belt 13 made of an endless belt, and the sheet is nipped and conveyed between the fixing roller 11 and the pressure belt 13. In this configuration, fixing is performed. Therefore, a sufficient nip width can be obtained as compared with the roller fixing method. This achieves higher image quality and higher speed in image formation.

  As described above, since the pressure belt 13 rotates even during standby, wear occurs with the rollers 14 and 15 that stretch the belt. Further, during image formation, the pressure pad 18 is pressed against the inner surface of the belt and the pressure belt 13 is pressed against the fixing roller 11, and wear occurs between the pressure pad 18.

  Therefore, oil is continuously applied to the inner surface of the pressure belt 13 by an oil application roller 16 such as an oil application roller in order to prevent a decrease in durability due to wear and to reduce a load during durability. There exists what was comprised so that it might do (patent document 1).

  Further, as a technical problem of the image heating apparatus using a belt, there is a meandering of the belt. If the belt exceeds the belt running range set by meandering, the belt will not rotate smoothly, and if the meandering becomes large, the belt may be damaged.

  In order to solve this problem, conventionally, a method is adopted in which the belt is caused to travel within a predetermined range by swinging a steering roller 15 which is one of the rollers for suspending the belt (Patent Document 1). .

JP 2005-292713 A

  In the belt fixing system as described above, the generation source of the sliding resistance of the belt is generated at two places in the nip. The first is a pressure contact portion where the pressure pad 18 and the fixing roller 11 are in pressure contact with each other via the pressure belt 13, and the second is a contact portion between the pressure pad tip and the roller 14. In such a configuration, the oil application roller 16 for reliably supplying oil to the sliding resistance generation source is arranged at the most upstream of the pressure contact portion. Therefore, the oil application roller 16 is disposed on the upstream side of the pressure pad 18.

  In the belt fixing method, the belt suspension means may be minimized by using two rollers for suspending the belt in order to realize cost reduction and space saving. In this case, the steering roller 15 is necessarily arranged upstream of the oil application roller 16.

  However, when the steering roller 15 is swung for the deviation control, the contact of the oil application roller 16 with the inner surface of the belt becomes uneven. If the oil application roller 16 is not evenly in contact with the inner surface of the belt, the oil will not be applied uniformly in the longitudinal direction of the belt 13, the sliding resistance inside the belt will be uneven, and the belt deviation control will be unstable. become. In addition, only a portion with a small amount of oil in the longitudinal direction of the belt is internally scraped, which causes problems such as an increase in driving torque.

  In order to avoid the above problem, as shown in FIG. 10, the oil application roller 16 is supported by a rotatable support member 17 around the rotation shaft of the steering roller 15, and the oil application roller 16 is urged against the inner surface of the belt. It is conceivable to provide an urging means 19 for making it happen.

  However, in the above system, especially when the belt 13 is made hard (metal), the rigid one is twisted by the steering roller 15, so that the oil application roller 16 contacts the inner surface of the belt 13 uniformly in the longitudinal direction following the twist. It is difficult to do. Further, if the contact pressure of the oil application roller 16 to the belt 13 becomes too high, a large amount of oil will be discharged.

  Further, when the oil application roller 16 is swung with the steering roller 15 while being in contact with the inner surface of the belt, the oil application roller roller 16 becomes a roller roller for suspending the belt 13. This breaks the distance relationship between the contact portion between the heating roller roller 11 and the pressure pad 18 that is an important restraint point of the belt 13 and the belt 13 winding portion of the steering roller roller 15 in controlling the shift. , It becomes a factor that makes the shift control unstable.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an image heating apparatus that can accurately control the deviation of a traveling belt and apply oil to the belt.

  Representative means in the present invention for solving the above problems are an endless belt and a rotating body for heating a toner image on a sheet therebetween, a roller for supporting the belt so that the belt can run from the inside thereof, An image heating apparatus comprising: a pad that pressurizes the belt against the rotating body by applying pressure from the inside; and a lubricant supply member that supplies a lubricant to the inner surface of the belt. It is characterized in that the lubricant is supplied through the roller by abutting.

  In the present invention, the lubricant supply member may affect the belt side by contacting the lubricant supply member with the roller supporting the belt and applying the lubricant to the inner surface of the belt through the roller. Absent.

  Next, an image heating apparatus according to an embodiment of the present invention will be described with reference to the drawings together with an image forming apparatus including the image heating apparatus.

[First Embodiment]
[Entire configuration of image forming apparatus]
First, the overall configuration of the image forming apparatus will be described together with the image forming operation with reference to FIG. The image forming apparatus shown in FIG. 1 is an image forming apparatus that employs an electrophotographic system.

  The image forming apparatus 100 is roughly divided into an image forming unit that forms a toner image on a sheet as a recording material, and an image heating apparatus that fixes an unfixed image by heating and pressurizing the toner image formed on the sheet. A fixing device is provided.

  The image forming means is provided with process means such as a charger 103 and a developing device 106 as charging means around a photosensitive drum 102 as an image carrier. During image formation, the surface of the rotating photosensitive drum 102 is uniformly charged by a charger 103, and a laser beam 105 corresponding to the image is emitted from an exposure device 104 serving as an exposure unit. As a result, an electrostatic image is formed on the photosensitive drum 102, and the electrostatic image is developed by a developing device 106 as a developing unit to form a toner image.

  On the other hand, the sheet S as a recording material is stored in a feeding cassette 109 at the lower part of the apparatus and is fed by a feeding roller 110. The sheet is conveyed in synchronism with the toner image on the photosensitive drum 102 by a pair of registration rollers 111 as conveying means.

  The toner image on the photosensitive drum is electrostatically transferred onto the sheet by a transfer roller 107 as a transfer unit, and is conveyed to the fixing device 114. Thereafter, the toner remaining on the photosensitive drum 102 is removed by a cleaning device 108 as a cleaning unit.

  The toner image formed on the sheet S by the image forming unit is fixed on the sheet by being heated and pressed by a fixing device 114 as an image heating device. Thereafter, the sheet S on which the toner image is fixed is conveyed and discharged by a discharge roller pair 112 to a discharge tray 113 at the top of the apparatus.

[Fixing device]
Next, the fixing device 114 of this embodiment will be described with reference to FIG. In FIG. 2, 11 is a heating roller roller which is a rotating body having an internal halogen heater 12 therein. Heat generated by the heating roller 11 is applied to the toner T on the sheet S via an endless belt (hereinafter referred to as “belt”) 13 and the sheet S is nipped and conveyed together with the belt 13.

  The belt 13 is supported by two support rollers which are support members that support the belt so that the belt can run. That is, the belt 13 is looped around the pressure roller 14 and a steering roller 15 having a belt steering function and a belt tension function so as to be able to circulate and rotate with a predetermined tension (for example, 100 N). The belt 13 may be appropriately selected as long as it has heat resistance. For example, a stainless belt coated with silicon rubber may be used.

  On the inner side of the belt 13 corresponding to the inlet side (upstream side of the pressure roller 14) of the nip region between the heating roller 11 and the belt 13, a pressure pad formed of, for example, silicon rubber, which presses the belt against the heating roller 11 18 is pressed against the heating roller 11 with a predetermined pressure (for example, 400 N). Thus, a nip is formed together with the pressure roller 14.

  The pressure roller 14 is a roller that suspends the belt 13. The outer diameter of the pressure roller 14 is made of, for example, solid stainless steel, and is arranged on the downstream side of the nip region between the heating roller 11 and the belt 13. The layer is elastically distorted by a predetermined amount. In addition, a halogen heater (not shown) is disposed inside the pressure roller 14 so as to be constant at a predetermined temperature based on a temperature detected by a temperature detection means (not shown) that detects the temperature of the pressure roller 14. The temperature is controlled by turning on / off the current to the halogen heater.

  Further, as shown in FIG. 3, a drive input gear 70 is attached to one end portion of the heating roller 11. The drive input gear 70 is a drive input gear for receiving rotational drive from the image forming apparatus 100 main body side.

  Further, the steering roller 15 is a hollow roller having an outer diameter of about 20 mm and an inner diameter of about 18 made of stainless steel, for example. The steering roller 15 functions as a steering roller that adjusts the meandering in the width direction perpendicular to the moving direction of the belt 13, and Also works as a roller.

[Belt moving means]
The fixing device 114 of the present embodiment is provided with a moving unit that moves the belt 13 in the width direction by displacing at least one longitudinal end of the steering roller 15 that applies tension to the belt 13 by a motor. Next, the configuration of the moving means for regulating the deviation of the belt 13 will be described.

  As shown in FIG. 3, the steering roller 15 is attached to the steering roller support arm 54 so as to be rotatable and to be slidable in a direction in which tension is applied to the belt 13 with respect to the support arm 54. The steering roller 15 is urged in the tension applying direction by a tension spring 56 held by the support arm 54 so as to rotatably support the steering roller 15.

  The steering roller support arm 54 is supported so as to be rotatable about a shaft 55 fixed to the outside of the side plate 20. A fan-shaped gear 52 is fixed to the outer periphery of the steering roller support arm 54, and meshes with a worm 51 that can be rotationally driven by the driving of the stepping motor 50. When the worm 51 rotates, when the support arm 54 rotates about the shaft 55 via the sector gear 52, the longitudinal end of the steering roller 15 is displaced in the direction of arrow B in FIG.

  A belt position detection unit 80 for detecting the belt end position is provided at the width direction end of the belt 13.

  FIG. 3 shows approximately half of the fixing device 114 in the longitudinal direction, and the other half is completely symmetrical except for the drive input gear 70 and the belt position detection unit 80.

  In the belt position detection unit 80, a belt position detection arm 83 and a sensor flag 82 are integrated, and can rotate around a rotation shaft 84. The belt position detection arm 83 is always in light contact with the end surface of the belt 13 by the biasing spring 85. As shown in FIG. 4, the sensor flag 82 is provided with a notch 82a and a notch 82b.

  The belt position detection arm 83 and the sensor flag 82 follow the movement of the belt 13 in the width direction (arrow F and arrow R directions) and rotate around the rotation shaft 84.

  The photosensors 81a and 81b detect the notches 82a and 82b provided in the sensor flag 82 that is moved by the movement of the belt 13 in the width direction by an ON / OFF signal. Then, as shown in FIG. 5, the current position of the belt 13 is determined based on the ON / OFF states of the two photosensors 81a and 81b, and the steering roller 15 is displaced.

  Specifically, when the belt 13 approaches the arrow R side shown in FIG. 3, the belt position detection unit 80 detects the offset position R1 and sends it to a controller (not shown). At this time, the controller controls the rotation of the stepping motor motor 50 so as to move the sector gear 52 upward about the shaft 55. As a result, the belt 13 returns in the reverse direction, that is, the arrow F side shown in FIG.

  Conversely, when the belt 13 approaches the arrow F side shown in FIG. 3, the belt position detection unit 80 detects the offset position F1 and sends it to a controller (not shown). At this time, the controller controls the rotation of the stepping motor motor 50 so as to move the sector gear 52 downward about the shaft 55. As a result, the belt 13 returns in the reverse direction, that is, the arrow R side shown in FIG.

  The other half (not shown) of FIG. 3 is completely symmetrical except for the drive input gear 70 and the belt position detection unit 80, but the control operation is exactly the same.

  The belt 13 continues to meander by a series of repeated control operations described above. As a result, the belt 13 rotates without being too close to one side in the width direction. When an error occurs in the control and the belt 13 moves further to the lateral positions R2 and F2 (see FIG. 5) than the lateral positions R1 and F1, the belt 13 approaches the end. That ’s too much. For this reason, an error is displayed on the display unit and the image forming operation is stopped.

[Oil application configuration]
The fixing device 114 of the present embodiment is configured to apply oil, which is a lubricant, to the inner surface side of the belt 13, that is, the surface where the belt 13 is in contact with the pressure roller 14 and the steering roller 15, which are support members. . As a result, wear generated on the belt 13 pressed against the heating roller 11 by the pressure pad 18 and the pressure roller 14 is reduced. Next, the oil application configuration in the present embodiment will be described.

  In the present embodiment, as shown in FIG. 2, the oil application roller 16 is a roller impregnated with oil supplied to the inner surface of the belt and serves as a lubricant supply member. The oil application roller 16 is rotatably supported by an arm 17 via a bearing 16a. The arm 17 is supported by a bearing 53 of the steering roller 15.

  The position of the bearing 16a with respect to the arm 17 is arranged at a position where the contact area where the oil application roller 16 and the steering roller 15 are set can be secured, as shown in FIG.

  As described above, the oil application roller 16 is attached to the arm 17 attached to the bearing 53 of the steering roller 15, and the oil application roller 16 is brought into contact with the peripheral surface of the steering roller 15. The oil application roller 16 rotates following the rotation of the steering roller 15, and supplies the impregnated oil to the peripheral surface of the steering roller 15. As a result, the oil from the oil application roller 16 is applied to the inner surface of the belt via the steering roller 15. Even if the steering roller 15 is displaced, it is uniformly applied in the width direction of the inner surface of the belt.

  Further, since the oil application roller 16 is not in contact with the inner surface of the belt 13, the oil application roller 16 does not become a belt support roller. Therefore, in the shift restriction control by the steering roller 15, even if the rotation shaft of the steering roller 15 is displaced, the oil application roller 16 does not affect the shift restriction of the belt 13.

  In the above-described embodiment, the case where two rollers support the belt has been described. However, there may be a plurality of rollers supporting the belt, and there may be three or more rollers. The oil application roller 16 is in contact with the support roller located at the most upstream in the running direction of the belt 13 with respect to the nip that is the pressure contact portion between the belt 13 and the heating roller 11 among the plurality of support rollers. . As a result, the oil is reliably applied to the pressure contact portion between the pressure pad 18 and the belt 13 forming the nip, which is a source of sliding resistance.

  Even if the most upstream roller is a steering roller whose rotational axis is displaced, the oil application roller 16 does not affect the belt shift regulation control.

[Second Embodiment]
Next, an apparatus according to the second embodiment will be described with reference to FIG. Note that the basic configuration of the apparatus of the present embodiment is the same as that of the first embodiment described above, and thus a duplicate description is omitted. Only the configuration different from the first embodiment will be described here. Moreover, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above.

  In this embodiment, the oil application roller 16 is rotatably supported by the arm 17 via the bearing 16a. The bearing 16a is supported on the attachment portion of the bearing 16a of the arm 17 by an elongated hole 17a so as to be movable toward the center of the steering roller 15.

  A tension spring 19 as an urging means is attached between the bearing 16a and a roller bearing 53 which is the rotation center of the steering roller 15. This is to bias the oil application roller 16 toward the steering roller 15 so as to follow the displacement of the steering roller 15.

  As described above, by urging the oil application roller 16 against the steering roller 15, the contact pressure of the oil application roller 16 with respect to the steering roller 15 can be freely changed. For this reason, even if the shapes of the steering roller 15 and the oil application roller 16 vary, the contact pressure can be kept substantially constant.

[Third Embodiment]
Next, an apparatus according to a third embodiment will be described with reference to FIG. The basic configuration of the apparatus according to the present embodiment is also the same as that of the above-described embodiment, and thus redundant description is omitted. Here, only a configuration different from the above-described embodiment will be described. Moreover, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above.

  The image heating apparatus of the present embodiment is configured by configuring the heating roller 11 of the above-described embodiment with an endless belt 30 and providing a lubricant (oil) supply means on the inner surface side of the belt 30 for reducing sliding resistance. is there.

  The configuration of the belt 30 is the same as the configuration of the belt 13, and the configuration of the moving means is also the same. That is, the heating belt 30 having a metal layer such as nickel inside is suspended by a driving roller 31 and a steering roller 32 as a moving means. The pad stay 37 forms a nip together with the drive roller 31, the pressure roller 14, and the pressure pad 18. Reference numeral 35 denotes an induction heating coil, which heats the metal layer inside the heating belt 30.

  In addition, about the deviation control method of the heating belt 30, the same thing as the structure shown in 1st Embodiment is used.

  The oil application roller 33 as a lubricant supply member is supported by an arm 34 disposed at the end of the steering roller 32, is rotatably supported via a bearing 33a, and is in contact with the steering roller 32. As a result, the oil impregnated in the oil application roller 33 is applied to the inner surface of the belt 30 via the steering roller 32.

  Further, the oil application roller 33 is urged against the steering roller 32 by the urging means, similarly to the configuration shown in the second embodiment. That is, an elongated hole shape 34 a is formed in the attachment portion of the bearing 33 a of the arm 34 so that the bearing 33 a can move toward the center of the steering roller 32.

  A biasing spring 36 biases the oil application roller 33 toward the center of the steering roller 32. The spring 36 is engaged with the bearing 33a of the oil application roller 33 and the bearing 32a of the steering roller 32 to steer the oil application roller 33. The roller 32 is tensioned.

  Note that the oil application roller 16 and the oil application roller 33 may not be urged to the steering rollers 15 and 32 by the urging means, but may be configured as described in the first embodiment.

  Even if comprised as mentioned above, the effect similar to 1st Embodiment and 2nd Embodiment mentioned above can be acquired, and nip width | variety can be taken wide.

1 is an overall cross-sectional explanatory diagram of an image forming apparatus. It is sectional explanatory drawing of an image heating apparatus. It is a perspective explanatory view of an image heating device. It is explanatory drawing of a belt position detection structure. It is explanatory drawing of the sensor flag which detects the shift | offset | difference of a belt. It is a contact explanatory drawing of an oil application roller and a steering roller. It is a section explanatory view of the image heating device concerning a 2nd embodiment. It is a section explanatory view of the image heating device concerning a 2nd embodiment. It is explanatory drawing of the image heating apparatus which concerns on a prior art. It is explanatory drawing of the image heating apparatus which concerns on a prior art.

Explanation of symbols

S ... Sheet
11… Heating roller
12… Halogen heater
13… Pressure belt
14… Pressure roller
15 ... Steering roller
16… Oil application roller
16a ... Bearing
16a15… Bearing
17… arm
17a ... slot
18… Pressure pad
20… Side plate
30… heating belt
31… Drive roller
32… Steering roller
33a ... Bearing
33… Oil application roller
33a ... Bearing
34 Arm
34a ... Long hole shape
35… induction heating coil
37… Pad stay
50… Stepping motor
51… Warm
52… Sector gear
53… Roller bearing
54… Support arm
55 Axes
70… Drive input gear
80… belt position detection unit
81a, 81b ... Photosensor
82… Sensor flag
82a, 82b ... Notches
83… Belt position detection arm
84 Rotating shaft
85… Biasing spring
100 ... Image forming apparatus
102… Photosensitive drum
103… Charger
104 Exposure apparatus
105 ... Laser light
106… Developer
107… Transfer roller
108… Cleaning device
109… feed cassette
110… feed roller
111… Registration roller pair
112… discharge roller pair
113… discharge tray
114… Fixing device

Claims (2)

An endless belt and a rotating body for heating a toner image on the sheet therebetween, a roller for supporting the belt so that the belt can run from the inside, and a pad for pressing the belt against the rotating body by applying pressure from the inside of the belt And an image heating apparatus having a lubricant supply member for supplying a lubricant to the inner surface of the belt,
An image heating apparatus, wherein the lubricant is supplied through the roller by bringing the lubricant supply member into contact with the roller.   Moving means for moving the belt in the width direction by displacing at least one longitudinal end of the roller, and the lubricant supply member facing the roller so as to follow displacement of the roller by the moving means The image heating apparatus according to claim 1, further comprising an urging unit that urges the image.

Images