JP2019120800A - Image heating device - Google Patents

Abstract

To stably provide a lubricant to an internal member of an endless belt of an image heating device including a belt over a long term.SOLUTION: A lubricant is stably applied to the inside of a belt by a web impregnated with the lubricant. An image heating device is composed of two of a web supply roller 201 and a web take-up roller 202 of the web 200 impregnated with the lubricant. By making the web take-up roller 202 come into contact with an internal member of the belt, the lubricant can be stably applied in a compact and simple configuration.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image heating apparatus mounted on an image forming apparatus adopting an electrophotographic method, an electrostatic recording method, or the like, and heating an image on a recording material.

  In an image forming apparatus such as an electrophotographic apparatus and an electrostatic recording apparatus, a toner image is formed on a sheet-like recording material (hereinafter referred to as a sheet or a sheet of paper) and heated by a fixing device (image heating device). The image is formed by pressing and fixing. The fixing device is widely used to fix the image on a sheet by heating and pressing at the nip portion, and the pressing rotary member (belt member or roller member) is brought into pressure contact with the heating rotator (belt member or roller member) It is formed.

  In a belt fixing apparatus in which at least one of a heating rotating body and a pressing rotating body is a belt member (endless belt), the other rotating body is formed by a pressure contact member (pad member: pressure member) having the belt member disposed inside It is configured to be in pressure contact with the Therefore, if the friction between the inner surface of the belt member and the pressure-contacting member is large, the traveling of the belt member is hindered, which causes a fixing failure, paper wrinkles, and the like.

  For this reason, in the belt fixing device, in order to reduce the friction generated between the belt member and the pressure contact member and enable the smooth traveling of the belt member, a configuration in which a lubricant (oil) is supplied to the inner surface of the belt member is used. There are many things. An oil application roller is generally used as means for supplying a lubricant to the inner surface of the belt member, and the oil application roller is brought into contact with the inner surface of the belt member.

  However, in this configuration, while the fixing process is repeated, the lubricant gradually leaks from the end portion of the belt member, causing a problem of being attached to the sheet or staining the inside of the apparatus.

  Therefore, in Patent Document 1, lubricant is prevented from leaking from the end of the pressure belt in pressure contact with the heating roller, wear of the pressing contact member is reduced, and the lubricant adheres to the sheet or contaminates the inside of the apparatus. The following configuration has been proposed for the purpose of preventing the problem. That is, a lubricant application member for applying a lubricant, at least one pair of blade members that scrape the lubricant by sliding contact with the inner surfaces of both end portions in the width direction orthogonal to the rotation direction of the pressure belt The taken lubricant is collected in the lubricant application member.

  On the other hand, in the configuration in which the lubricant is supplied to the inner surface of the belt member, the application life of the lubricant application member is important. Therefore, in Patent Document 2, for the purpose of providing an image heating device capable of supplying a lubricant over a long period, time difference between lubricant supply timings of lubricant supply members provided along a rotation direction of an endless belt is provided. A configuration to provide

JP, 2008-164889, A JP, 2011-247982, A

  In the prior art, a roller (oil application roller) or non-woven fabric (oil application member) in which a lubricant application member is impregnated with oil is brought into contact with the inner surface of the belt. However, in the above configuration, when considering the application life, the lubricant holding amount of the lubricant application member becomes the limit of the lubricant application, so it is difficult to apply the lubricant for a long time.

  An object of the present invention is to stably supply a lubricant to an inner member of an endless belt of an image heating apparatus using a belt over a long period of time.

A typical configuration of the image heating apparatus according to the present invention for achieving the above object is
A pair of rotating members, at least one of which is an endless belt, which forms a nip for holding and conveying a recording material to heat an image on the recording material;
A pressing member provided slidably on the inner surface of the endless belt at the nip and pressing the endless belt toward the other rotating body;
A web supply roller disposed inside the endless belt and entraining a lubricant impregnated web member; and a web take-up roller for winding the web member from the side of the web supply roller,
The web member wound around the web winding roller applies a lubricant to an inner member of the endless belt.

  According to the present invention, the lubricant can be stably supplied to the inner member of the endless belt over a long period of time.

Cross-sectional schematic view of the main parts of the fixing device of Example 1 A schematic view showing a schematic configuration of an example of an image forming apparatus A schematic view of the left side of the main part of the fixing device of Example 1 and a block diagram of a control system Structure explanatory drawing of a lower belt unit (the 1) The same configuration explanatory drawing (the 2) The same configuration explanatory drawing (the 3) Cross-sectional schematic view of the main part of the fixing device of Example 2 Cross-sectional schematic view of the main parts of the fixing device of Example 3 Cross-sectional schematic view of the main parts of the fixing device of the reference example Experimental results of the fixing device of the reference example

  Hereinafter, embodiments of the present invention will be described. The present embodiment is an example of the best embodiment of the present invention, but the present invention is not limited by these embodiments.

Example 1
<Image forming apparatus>
FIG. 2 is a schematic view showing a schematic configuration of an example of an image forming apparatus (in the present embodiment, a monochrome printer) 100 using the electrophotographic recording technology.

  In the image forming apparatus 100, an image forming unit 101 for forming a toner image on a sheet-like recording material (hereinafter referred to as paper or paper) S is a photosensitive drum as an image carrier rotationally driven in the clockwise direction of an arrow. (Hereinafter referred to as a drum) 102 is provided. Further, the image forming unit 101 has a charging device 103, an exposure device 104, a developing device 105, a transfer roller 106, and a cleaning device 107 as an image forming process unit acting on the drum 102. The above-described image forming process and image forming operation of the image forming unit 101 are known, and therefore detailed description will be omitted.

  The sheets S are stored in a sheet feeding cassette 108, and are fed and fed sheet by sheet by a feeding roller 109. The fed sheet S is conveyed by the registration roller pair 110 in synchronization with the toner image on the drum 102. The toner image carried on the drum 102 is electrostatically transferred by the transfer roller 106 onto the conveyed sheet. The sheet S on which the toner image has been transferred is sent to a fixing device 114 as an image heating device, and the toner image which is an unfixed image is fixed on the sheet by heat and pressure. The sheet S having exited the fixing device 114 is discharged as an image forming product (deliverable) to the discharge tray 112 at the top of the apparatus by the discharge roller pair 111.

<Fixing device>
Here, with regard to the fixing device 114 of this embodiment or members constituting the same, the longitudinal direction (longitudinal direction) or the width direction (width) is a direction parallel to the direction orthogonal to the sheet conveyance direction in the sheet conveyance road surface. is there. The short side direction (short side) is a direction parallel to the sheet conveyance direction in the sheet conveyance road surface. The front of the fixing device 114 is the surface on the sheet inlet side, the back is the surface on the sheet outlet side, and the right and left are the left (front side) or the right (rear side) when the apparatus is viewed from the front. Up and down are up and down in the direction of gravity. The upstream or downstream is upstream or downstream with respect to the sheet conveyance direction. The width of the belt or sheet is a dimension in the direction orthogonal to the sheet conveyance direction.

  FIG. 1 is a schematic cross-sectional view of the main part of the fixing device 114. As shown in FIG. FIG. 3 is a schematic view of the left side of the main part of the apparatus 114 and a block diagram of a control system. The fixing device 114 is a belt fixing device and roughly includes an upper belt unit U1 as a heating unit and a lower belt unit U2 as a pressure unit.

[Upper belt unit]
The upper belt unit U1 has a fixing belt 30 which is an endless belt having flexibility as a heating rotating body (first rotating body: belt-like fixing member) facing the image bearing surface of the sheet S. The fixing belt 30 is formed to be able to generate heat by an electromagnetic induction coil, and has a metal layer.

  Further, the upper belt unit U1 is a plurality of stretching members for stretching the fixing belt 30, and includes a driving roller (driving rotating body: fixing roller) 31, an upper steering roller 32 also serving as a tension roller, and a pad stay. (Pressing member: pressure contact member) 37 is provided. The upper belt unit U1 also has an electromagnetic induction coil 35 for inductively heating the fixing belt 30.

  The driving roller 31 is, for example, a roller in which a heat resistant silicone rubber elastic layer is integrally formed as a surface layer on a core metal formed of a solid stainless steel material and the core metal. The left and right shafts of the drive roller 31 are rotatably supported between the left and right side plates of a main frame (not shown) of the fixing device 114 via bearing members (bearings and the like).

  The upper steering roller 32 is located upstream of the drive roller 31 in the sheet conveyance direction, and the left and right shaft portions are rotatably supported between the left and right side plates of the main frame via bearing members. The right side (rear side) shaft portion of the upper steering roller 32 is fixed, and the left side (front side) shaft portion can swing in the vertical direction of the arrow in FIG.

  The pad stay 37 is formed of, for example, a stainless steel material, and is fixedly disposed between the left and right side plates of the main frame in the vicinity of the drive roller 31 between the drive roller 31 and the tension roller 32. The fixing belt 30 is wound around the three members 31, 32 and 37.

  The inner surface of the lower belt portion of the fixing belt 30 is slidably in contact with the downward pad receiving surface of the pad stay 37. A sheet member (sliding sheet) 33 obtained by baking a fluorocarbon resin is provided on the sliding surface of the pad stay 37 with the fixing belt 30 to reduce the frictional resistance with the fixing belt 30.

  The upper steering roller (tension roller) 32, which also functions as a tension roller, is biased by a tension spring 36 in a direction to apply tension to the fixing belt 30, and applies a suitable tension, for example, 120 N, to the fixing belt 30.

  The driving roller 31 is rotationally driven at a predetermined speed in the clockwise direction of the arrow by a driving mechanism 116 controlled by a control unit (CPU) 115. By the rotation of the drive roller 31, the fixing belt 30 is circularly conveyed at the speed corresponding to the speed of the drive roller 31 in the clockwise direction of the arrow B (rotation by rotation).

  Then, a high frequency current is supplied from the power supply unit 117 controlled by the control unit 115 to the electromagnetic induction coil 35, whereby the rotating fixing belt 30 is heated by electromagnetic induction. The surface temperature of the fixing belt 30 is detected by the temperature sensor TH, and the detected temperature information is input to the control unit 115. The control unit 115 controls power supplied from the power supply unit 117 to the electromagnetic induction coil 35 so that the surface temperature of the fixing belt 30 is maintained at a predetermined fixable temperature based on the input detected temperature information.

  The upper steering roller 32 is pivoted in the vertical direction by the operation of the upper steering mechanism 118 controlled by the control unit 115. As a result, the inclination angle of the rotation shaft of the upper steering roller 32 is alternately inclined, and the fixing belt 30 which has been displaced while rotating is returned to the original normal position. That is, by the upper steering mechanism 118 controlled by the control unit 115, the steering operation for reciprocating the fixing belt 30 in the width direction is executed by swinging the upper steering roller 32 so that the fixing belt 30 does not slip off. Ru.

[Lower belt unit]
The lower belt unit U2 is disposed below the upper belt unit U1. The lower belt unit U2 is an endless belt having flexibility as a pressure rotating body (second rotating body: belt-like pressure member) forming the fixing belt 30 and the fixing nip portion N of the upper belt unit U1. The pressure belt 11 is provided. The lower belt unit U2 is a plurality of tension members for tensioning the pressure belt 11, the pressure roller 12, the lower steering roller 13 which also functions as a tension roller, and a pressure pad (pressure member (pressure member: A pressure contact member 14 is provided. Further, the lower belt unit U 2 has a lubricant application mechanism 20 for the inside of the pressure belt 11.

  The pressure roller 12 has its left and right shafts rotatably supported via bearing members between the left and right side plates of a unit frame (not shown) of the lower belt unit U2. The unit frame is vertically swingable relative to the main frame of the fixing device 114.

  The lower steering roller 13 is positioned upstream of the pressure roller 12 in the sheet conveying direction, and the left and right shaft portions are rotatably supported between the left and right side plates of the unit frame via bearing members. The right side shaft portion of the lower steering roller 13 is fixed, and the left side (front side) shaft portion can swing in the vertical direction of the arrow in FIG.

  The pressure pad 14 is formed of, for example, silicone rubber, and is disposed in a fixed position between the left and right side plates of the unit frame in the vicinity of the pressure roller 12 between the pressure roller 12 and the lower steering roller 13. The pressure belt 11 is wound around the three members 12, 12 and 14.

  The inner surface of the belt portion on the upper side of the pressure belt 11 is slidably in contact with the upward surface of the pressure pad 14. A sheet member (sliding sheet) 18 obtained by firing a fluorine resin is provided on the sliding surface (sliding portion) of the pressure pad 14 with the pressure belt 11 to reduce the frictional resistance with the pressure belt 11. ing.

  The lower steering roller 13, which also serves as a tension roller, is urged to move in a direction to apply tension to the pressure belt 11 by a tension spring 15, and applies, for example, 100 N which is an appropriate tension to the pressure belt 11.

  The lower steering roller 13 is pivoted in the vertical direction by the operation of the lower steering mechanism 119 controlled by the control unit 115. As a result, the inclination angle of the rotation shaft of the lower steering roller 13 is alternately inclined to return the pressure belt 11 shifted to the original position when rotating. That is, the lower steering mechanism 119 controlled by the control unit 115 performs a steering operation for reciprocating the pressure belt 11 in the width direction by swinging the lower steering roller 13 so that the pressure belt 11 does not slip off. To be executed.

[Pressure-separation mechanism]
The lower belt unit U2 is moved to the pressed position and the separated position by the pressure-separation mechanism 120 controlled by the control unit 115 with respect to the upper belt unit U1. FIGS. 1 and 3 show a state in which the lower belt unit U2 is moved to the pressing position by the pressing-separating mechanism 120 with respect to the upper belt unit U1.

  Although the specific configuration of the pressure-separation mechanism 120 is omitted in the figure, for example, an eccentric cam mechanism for lifting and holding the lower belt unit U2 with respect to the upper belt unit U1 and an electromagnetic solenoid mechanism etc. Be done.

  In a state in which the lower belt unit U2ga and the upper belt unit U1ni are moved to pressure one, the fixing nip portion N which is wide in the sheet conveying direction V between the fixing belt 30 which is a pair of rotating members and the pressure belt 11 Is formed.

  That is, the pressing nip 12 is formed between the fixing belt 30 and the pressing belt 11 by the pressing of the pressing roller 12 against the driving roller 31 and the pressing of the pressing pad 14 against the pad stay 37. In this case, when the drive roller 31 is in pressure contact with the pressure roller 12, the elastic layer is elastically distorted by a predetermined amount. The pressure pad 14 is pressed against the pad stay 37 across the pressure belt 11 and the fixing belt 30 with a set pressure of 400 N, for example.

Fixing Operation
In a state where the lower belt unit U2 is moved to the pressing position with respect to the upper belt unit U1, the drive roller 31 is rotationally driven, and the fixing belt 30 rotates in the clockwise direction of arrow B at a predetermined circumferential speed. The pressure belt 11 follows the rotation of the fixing belt 30 and rotates in the counterclockwise direction of arrow C at a peripheral speed corresponding to the rotation of the fixing belt 30. The pressure roller 12 is also driven to rotate (rotation by rotation).

  Further, the fixing belt 30 which is rotating is subjected to electromagnetic induction heating to a predetermined fixable temperature and temperature-controlled. In this apparatus state, the sheet S on which the unfixed toner image T is formed in the image forming unit 101 of the image forming apparatus 100 is introduced. Then, the sheet S is nipped and conveyed by the fixing nip portion N, and the unfixed toner image T is heated and pressurized in the conveyance process, whereby the sheet S is fixed as a fixed image on the sheet P.

[Steering mechanism]
Although specific configurations of the upper and lower steering mechanisms 118 and 119 are omitted in the figure, the shift movement of the fixing belt 30 and the pressure belt 11 is stabilized within a predetermined shift range by swing type shift control. The swing type shift control is a method of tilting the steering roll in the direction opposite to the shift direction of the belt when it is detected that the belt position has moved from the center in the width direction by a predetermined amount or more. By repeating this swing-type shift control, the fixing belt 30 and the pressure belt 11 are periodically moved from one side in the width direction (one side in the width direction) to the other side (the other direction in the width direction), You can control the movement of the

[Lubricant application mechanism]
In this embodiment, as shown in FIG. 1, a lubricant application mechanism 20 for the inside of the pressure belt 11 is disposed inside the pressure belt 11 of the lower belt unit U2. In the present embodiment, the application mechanism 20 applies a lubricant to the inner surface of the pressure belt 11.

  In the lower belt unit U2 of the apparatus state of FIG. 1, the inner peripheral surface of the pressure belt 11 and the pressure pad 14 slide at a pressure applied to the upper belt unit U1 under a predetermined pressure. When the sliding resistance is large, the pressure belt 11 and the fixing belt 30 have a peripheral speed difference in the sheet conveying direction V at the fixing nip portion N, and image rubbing occurs when the sheet S is conveyed. Therefore, the sheet member 18 which is a sliding sheet is disposed on the inner peripheral surface of the pressure belt 11 and the sliding surface of the pressure pad 14, and the oil which is a lubricant is made to the sliding surface using the application mechanism 20. Supply.

  The application mechanism 20 has a web (web member) 200 impregnated with oil, which is a lubricant, as a sheet-like cleaning member, a web supply roller 201, and a web winding roller 202. Hereinafter, the application mechanism 20 will be described in detail.

(1) Oil-coated web configuration The web 200 is a non-woven fabric etc. in which aramid fibers etc. are knitted, and in order to share oil which is a lubricant between the inner surface of the pressure belt 11 and the sheet member 18 at the fixing nip N The oil is impregnated. The web 200 may be any flexible member that can be impregnated with a lubricant.

  As the oil impregnated in the above-mentioned web 200, silicone oil is preferably used from the viewpoint of heat resistance and the like. Among them, those of various viscosities are used depending on the conditions of use, but those having too high viscosity have poor fluidity at the time of coating. Therefore, those having 30,000 cSt or less are usually used. Specific examples of such oil include dimethyl silicone oil, amino-modified silicone oil, fluorine-modified silicone oil and the like, but are not particularly limited thereto.

  The application mechanism 20 includes a web supply roller 201 for holding an unused web 200 impregnated with oil, and a web take-up roller 202 for applying the oil to the inner surface of the pressure belt 11 and then taking up the used web. Composed of books.

  The web supply roller 201 holding the web 200 has an axial center (central axis) 201a, and the web 200 is wound around the web by being laminated in a roll. On the other hand, the web take-up roller 202 has an axial core 202a, around which the web 200 unwound from the web supply roller 201 is rolled and wound in layers.

  The web take-up roller 202 is rotated by a drive unit 121 whose axis 202 a is controlled by the control unit 115. The rotation is configured to wind the web 200 at a predetermined control timing for a predetermined short length. As a result, the contact surface of the web 200 with the inner surface of the pressure belt 120 is successively renewed.

  The web 200 wound around the web take-up roller 202 and the web supply roller 201 is arranged in an S-shape. The web 200 is wound around the two rollers 202 and 201 in an S-shape, thereby reducing the area occupied by the web supply roller 201 and the web winding roller 202 inside the pressure belt 11. Can (Configuration X).

(2) Abutment of Inner Surface of Pressure Belt 11 In the present embodiment, the web take-up roller 202 is brought into contact with the inner surface of the pressure belt 11. In order to share oil as a lubricant between the inner surface of the pressure belt 11 and the sheet member 18 at the fixing nip N, the web take-up roller 202 is upstream of the fixing nip N in the rotational direction of the pressure belt 11. Place on In this embodiment, an example is shown in which the fixing nip portion N and the lower steering roller 13 are disposed and in contact with the inner surface of the pressure belt 11, but the abutting position is in the vicinity of the nip portion N Is better.

  The shaft core 202 a of the web take-up roller 202 is rotated in the rotational direction D shown in FIG. 1 by the drive unit 121 controlled by the control unit 115, and takes up the web 200 from the web supply roller 201. The drive unit 121 functions as a drive source for feeding the web from the web supply roller 201 to the web take-up roller 202. A drive for feeding the web is more preferably connected to the web take-up roller 202 as in this embodiment.

  It is more difficult to slacken the web 200 and more stable to feed the web 200 by winding the web 200 by driving the web take-up roller 202 than by feeding the web 200 by driving the web supply roller 201. it can.

  The rotational direction D of the web take-up roller 202 is rotated to face the rotational direction C of the pressure belt 11 at the contact portion between the web 200 and the inner surface of the pressure belt 11. The rotational directions of the two are arranged opposite to each other. That is, the rotational direction in which the web take-up roller 202 takes up the web 200 is reverse to the rotational direction of the belt 11 on which the web 200 abuts. This makes it difficult for the web 200 to be pulled out by the rotation of the belt 11, so that the web 200 wound around the web take-up roller 202 can be less likely to slacken.

  Thus, the rotational force of the pressure belt 11 at the contact portion between the pressure belt 11 and the web winding roller 202 can reduce the loosening of the web 200 wound on the web winding roller 202. (Configuration Y).

  The web 200 is arranged in the shape of S (configuration X), and the winding direction of the web take-up roller 202 and the rotation direction of the pressure belt 11 are opposed (configuration Y). Thereby, the E side surface of the wound web 200 of the web supply roller 201 can be brought into contact with the inner surface of the pressure belt 11. That is, a fresh surface can be brought into contact with the member in the web 200 wound around the web supply roller 201, and the adhesion of foreign substances such as abrasion powder generated inside the pressure belt 11 can be reduced.

(3) Holding Configuration of Web Take-Up Roller FIG. 4 is a perspective view for explaining the inner configuration of the lower belt unit U2. In order to explain the configuration of the web winding roller 202 and the web supply roller 201, the internal configuration of the lower belt unit U2 with the pressure belt 11 removed is shown.

  Side plates 205 and 206 are provided at both ends in the longitudinal direction of the lower belt unit U2. The side plates 205 and 206 hold both ends of the pressure roller 12, the pressure pad 14, and the lower steering roller 13. The pressure pad 14 has positioning protrusions 14 a and 14 b at both ends, and is fitted in positioning holes (not shown) respectively provided on the side plates 205 and 206 and positioned relative to the side plates 205 and 206. .

  Both end portions of the pressure roller 12 are attached to the side plates 205 and 206 via bearings or the like (not shown) and rotatably supported. Further, the lower steering roller 13 has relief holes 205a and 206a in the side plates 205 and 206 near both ends of the steering roller 13 in consideration of the movable range in order to perform the "steering" operation.

  Holding members 203 and 204 are disposed at both longitudinal end portions of the steering roller 13. The holding members 203 and 204 are rotatably supported by the steering roller 13 via a bearing or the like (not shown).

  FIG. 5 is a partially enlarged perspective view for explaining the method of holding the web supply roller 201 and the web winding roller 202, and shows the side plate 206 side in FIG. In the present embodiment, since the side plate 205 side has the same configuration as the side plate 206 side shown in FIG. 5, an enlarged view of the side plate 205 side is omitted.

  The web supply roller 201 is pivotally supported by bearings 206 c on side plates 206 disposed at both ends thereof. Although not shown, the side plate 205 also has a bearing portion 205c. Thus, the web supply roller 201 is supported at both ends by the side plates 205 and 206.

  Both end portions of the web take-up roller 202 are supported by bearing portions 203 a on the holding member 203. Although not shown, the side plate 205 is also supported by the bearing portion 204 a on the holding member 204. Thus, both end portions of the web take-up roller 202 are rotatably supported by the bearing portions 203a and 204a.

(4) Abutment Method of Web Take-up Roller FIG. 6 is a cross-sectional view for explaining a configuration in which the web take-up roller 202 is brought into contact with the inner surface of the pressure belt 11.

  The holding members 203 and 204 disposed at both ends of the web winding roller 202 have spring hook portions 203 b and 204 b. Further, spring side portions 205b and 206b are also provided on the side plates 205 and 206 of the pressure belt unit U2. The spring 207b is disposed on the spring hooking portion 206b and the spring hooking portion 203b. Similarly, the spring 207a is disposed on the springing portion 205b and the springing portion 204b. As a result, the web take-up roller 202 is brought into contact with the inner surface of the pressure belt 11 with a predetermined pressure in the direction of the arrow F about the steering roller 13.

  By using the above configuration, the lubricant is stably supplied to the inside of the belt stretched by the plurality of roller pairs by the web 200 impregnated with the lubricant.

  As in the above-described embodiment, the configuration is made by combining the web supply roller 201 of the web 200 impregnated with a lubricant, the web take-up roller 202, and bringing the web take-up roller side into contact with the inner surface of the belt. And it can supply stably by simple composition.

Example 2
FIG. 7 is a main part view of the fixing device 114 of the second embodiment. In the fixing device 114 of the first embodiment, the lower steering roller 13 of the lower belt unit U2 is also used as a tension roller. In the second embodiment, the lower steering roller 13 is not used as a tension roller but is functionally separated and a dedicated tension roller 21 is separately provided. The other device configuration is the same as the fixing device configuration of the first embodiment.

Example 3
FIG. 8 is a main part view of the fixing device of the third embodiment. The present embodiment is different from the first embodiment only in that the web take-up roller 202 of the first embodiment is brought into contact with the outer surface of the steering roller 13 instead of the inner surface of the pressure belt 11. The other fixing device configuration is the same as that of the first embodiment, so the description will be omitted.

  The web take-up roller 202 is held by a holding member 204. The holding member 204 is rotatably held by a support shaft 206 c disposed on the side plate 206. The web take-up roller 202 rotates about the support shaft 206c, receives force in the direction indicated by the arrow F by its own weight and the spring force of the pressure spring 207b, and abuts on the steering roller 13.

  The web take-up roller 202 is driven by the drive unit 121 controlled by the control unit 115 and winds the web 200 in the rotational direction G. Here, the rotation direction G of the web take-up roller 202 is rotated so as to face the rotation direction C of the steering roller 13. That is, the rotational direction in which the web take-up roller 202 takes up the web 200 is reverse to the rotational direction of the steering roller 13 with which the web 200 is in contact.

  As in the first embodiment, the rotational directions of the two are arranged opposite to each other. As a result, the rotational force of the steering roller 13 at the contact portion between the steering roller 13 and the web winding roller 202 can reduce the slack of the web 200 wound on the web winding roller 202.

  Although the detailed view is omitted, the web supply roller 201 is held by the side plate 206 as in FIG. 5 of the first embodiment.

  By using the above configuration, the web take-up roller 202 which takes up the oil-impregnated web 200 applies the oil to the outer surface of the steering roller 13. The application oil is transferred from the steering roller 13 to the inner surface of the pressure belt 11 and supplied between the sheet members 18.

  As a result, a constant lubricant can be stably supplied for a long period of time between the inner surface of the pressure belt 11 and the pressure contact member (the sheet member 18, the pressure pad 14), and a long life can be realized. Become.

Reference Example
FIG. 9 is a schematic view of a fixing device according to this embodiment. In this fixing device, the oil application mechanism in the lower belt unit U2 of the fixing device 114 of the first embodiment is configured as an oil application roller 38. FIG. 10 shows the experimental results examined by the present inventor using this fixing device.

  In FIG. 10, the time transition of the oil impregnation amount impregnated in the oil application roller 38 (solid line) and the time transition of the driving torque necessary to rotate the fixing belt 30 and the pressure belt 11 in a nipped state (dotted line) Indicates

  The lubricant impregnated in the oil application roller 38 indicated by a solid line tends to be attenuated with respect to time. In consideration of the durability, the oil application roller 38 is impregnated with a lubricant abundantly, but a large amount is released at the beginning.

  On the other hand, the drive torque indicated by the dotted line tends to increase with respect to the time axis of the horizontal axis. In particular, when A-A 'is exceeded, the amount of oil impregnation becomes a constant value, the drive torque reaches an inflection point, and the drive torque increases. As for the condition between the inner surface of the pressure belt member and the pressure contact member, boundary lubrication or individual lubrication is achieved after A-A ', which causes wear of the member and an increase in drive torque, which hinders the long life of the part.

<< Other matters >>
(1) In the fixing device 114 of the embodiment, the upper belt unit U1 may be configured as a roller having a heat source. In this case, the lower belt unit U2 is provided with the above-described application mechanism for applying a lubricant to the inner circumferential surface of the endless belt.

  The application mechanism is intended to suppress an increase in driving torque due to the friction between the inner circumferential surface of the endless belt and the members in the endless belt. Therefore, among the roller body and the lower belt unit U2, it is more preferable that the roller body be a drive rotating body that rotates in response to the drive from the drive source. Conversely, the lower belt unit U2 may be configured as a roller body. In this case, the above-described application mechanism for applying a lubricant to the inner circumferential surface of the endless belt is provided to the upper belt unit U1.

  Similarly, the application mechanism is intended to suppress an increase in driving torque due to the friction between the inner circumferential surface of the endless belt and the members in the endless belt. Therefore, among the upper belt unit U2 roller body, it is more preferable that the roller body be a drive rotating body that rotates in response to the drive from the drive source. That is, the fixing device 114 may be configured as a device having a pair of rotating members in which at least one is an endless belt forming a nip N that nips and conveys a sheet to heat the image T on the sheet (recording material). it can.

  (2) In the fixing device 114 of the embodiment, an application mechanism for applying a lubricant to the inner member of the fixing belt 105 can also be provided for the upper belt unit U1.

  (3) The pressure-separation mechanism for forming and separating a nip on a pair of rotating members, at least one of which is an endless belt, presses the lower belt unit U2 against the upper belt unit U1 as in the embodiment. -It is not restricted to the structure made to space apart. The upper belt unit U1 may be pressed and separated from the lower belt unit U2, or both the upper and lower belt units U1 and U2 may be pressed and separated.

  Here, the above-mentioned separation of the pressure-separation mechanism includes two forms, a form in which a pair of rotating bodies are separated, and a form in which a force is reduced without pressure without being separated. Shall be

  (4) In the embodiment, as the image heating device, the fixing device for heating and fixing the unfixed toner image T formed on the sheet is described as an example, but the invention is not limited thereto. The present invention can also be applied to a device that reheats a toner image fixed or temporarily attached to the sheet P to increase the gloss of the image.

  (5) In the image forming apparatus on which the image heating apparatus is mounted, the image forming unit for forming a toner image on a sheet may be a known transfer method such as electrophotographic method, electrostatic recording method, magnetic recording method or direct method The image forming unit of the image forming method of

  114 · · Image heating device (fixing device), U1 · · · upper belt unit, U2 · · · lower belt unit, 30 · · · fixing belt, 11 · · pressure belt, 14 · · · pressure member, N · · · · · · · 20 · · Lubricant application mechanism, 200 · · · Web member impregnated with lubricant, 201 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

Claims (5)

A pair of rotating members, at least one of which is an endless belt, which forms a nip for holding and conveying a recording material to heat an image on the recording material;
A pressing member provided slidably on the inner surface of the endless belt at the nip and pressing the endless belt toward the other rotating body;
A web supply roller disposed inside the endless belt and entraining a lubricant impregnated web member; and a web take-up roller for winding the web member from the side of the web supply roller,
The image heating apparatus, wherein the web member wound around the web winding roller applies a lubricant to an inner member of the endless belt.   4. The image heating apparatus according to claim 3, wherein a rotational direction in which the web take-up roller takes up the web member is opposite to a rotational direction of the inner member against which the web member abuts. apparatus.   The image heating apparatus according to claim 1, wherein the web member taken up by the web take-up roller abuts on the inner surface of the endless belt.   3. The image according to claim 1, further comprising a stretching roller for stretching the endless belt, wherein the web member taken up by the web take-up roller abuts on the stretching roller. Heating device.   The image heating apparatus according to any one of claims 1 to 4, wherein the web member wound around the web supply roller and the web take-up roller is disposed in an S-shape and wound around. apparatus.