JP2017122840A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device that can prevent depletion of lubricant to suppress an increase in friction load and prevent outflow of the lubricant to the inside of the device so as to extend the life of the device.SOLUTION: In a fixing device comprising: a rotatable, endless fixing sleeve 1; a heat source 2 that heats the fixing sleeve 1; a nip forming member 6 that is disposed on the inside of the fixing sleeve 1; and a pressure roller 3 that is in contact with the nip forming member 6 with the fixing sleeve 1 therebetween to form a nip part N with the fixing sleeve 1, the fixing device conveying a recording medium carrying an unfixed image and fixing the unfixed image to the recording medium, the nip forming member 6 includes a lubricant holding part 6a that can hold a lubricant 30, and a lubricant discharge part 6b that discharges the lubricant 30 inside the lubricant holding part 6a to the upstream side in the direction of rotation of the fixing sleeve 1, and the fixing sleeve 1 is in contact with the nip forming member 6 at the nip part N with a lubricant layer therebetween and is rotated by a frictional force with the pressure roller 3 accompanying the rotation of the pressure roller 3.SELECTED DRAWING: Figure 6

Description

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

  In an image forming apparatus, an unfixed toner image is transferred to a recording material sheet, printing paper, photosensitive paper, electrostatic recording paper, etc. by an image transfer method or a direct method by an image forming process such as electrophotographic recording, electrostatic recording, and magnetic recording. Formed on recording material. As a fixing device for fixing an unfixed toner image, a contact heating method fixing device such as a heat roller method, a film heating method, and an electromagnetic induction heating method is widely used.

As an example of such a fixing device, a belt-type fixing device is known.
In recent years, with belt type fixing devices, further warm-up time (time required from room temperature to a predetermined printable temperature (reload temperature) such as when the power is turned on) and first print time (after receiving a print request, It is desired to shorten the time required for the printing operation after the printing preparation and the paper discharge to be completed.

  In response to this requirement, the entire belt can be warmed, the first print time from the heating standby time can be shortened, and the lack of heat during high-speed rotation can be eliminated, and it can be installed in high-production image forming devices. However, there has been proposed a fixing device (see, for example, Patent Document 1) that can obtain good fixability.

  FIG. 1 is a schematic diagram of a fixing device described in Patent Document 1. A pipe-shaped metal heat conductor is fixed inside the endless belt so that the movement of the endless belt can be guided, and the endless belt is heated via the metal heat conductor by a heat source in the metal heat conductor. Further, a pressure roller that forms a nip portion N in contact with the metal heat conductor via the endless belt is provided, and the endless belt is moved in the circumferential direction so as to rotate along with the rotation of the pressure roller. With this configuration, it is possible to warm the entire endless belt constituting the fixing device, to shorten the first print time from the heating standby time, and to solve the shortage of heat during high-speed rotation. Yes.

  On the other hand, in order to further save energy and improve the first print time, a configuration in which an endless belt is directly heated without using a metal heat conductor has been studied. In this configuration, the power consumption is reduced due to a significant improvement in heat transfer efficiency, and the first print time from the heating standby time can be further shortened. However, in this configuration, there is a problem that the contact member (nip forming member) provided inside the endless belt is worn by friction with the inner surface of the endless belt.

As a measure for reducing friction of the nip forming member, a configuration in which a lubricant is infiltrated and held in a sheet woven with fluorine-based fibers has been proposed (for example, see Patent Document 2).
In Patent Document 2, a porous lubricant holding member is installed on an abutting member (nip forming member) that abuts against a pressure member via an endless belt to form a nip portion, and the lubricant is retained. The configuration is described. The lubricant holding member is disposed so as to contact the inner peripheral surface of the fixing belt at the nip portion.

  In order to meet the demands for energy saving, the heat capacity is reduced by eliminating parts and the design to heat the vicinity of the nip results in the heat from the heating source being stored in the fixing device and the inside of the endless belt like toner When there was no member that absorbs heat and no mechanism for dissipating heat was provided, the temperature became high, and the degree to which the nip forming member was directly affected by heat increased.

  A fixing member such as an endless belt is usually made of a resin having a high heat resistance temperature (for example, PEEK, LCP, etc.) in consideration of a high temperature. For example, in order to ensure the rigidity under high temperature conditions and the frictional conditions for low torque, it has been proposed to apply a coating having excellent sliding properties to a heat-resistant resin (see, for example, Patent Documents 3 and 4). . Further, a configuration in which a SUS metal sheet is wound around the stay member has been proposed (see, for example, Patent Document 5).

In either case, the rigidity is ensured at a high temperature and the friction structure is low torque, but there is a problem that the lubricant is depleted due to an increase in the thermal load at the nip portion.
Lubricant depletion leads to the occurrence of paper slip due to an increase in friction load, the occurrence of abnormal images and jams resulting from this, and the reduction in machine life due to an increase in motor load.

In the configuration in which the lubricant holding member holds the lubricant as described in Patent Document 2, the amount of lubricant that can be held is limited by the volume of the lubricant holding member. Since the lubricant applied in excess of the holdable amount oozes out from the lubricant holding member, it is not a countermeasure against depletion with time.
For example, as shown in the schematic diagrams of FIGS. 4A and 4B and the photograph of the inside of the apparatus in FIG. 4C, the excessively applied lubricant may leak into the apparatus. If the leaked lubricant adheres to the paper being passed, there is a problem that an abnormal image is formed.

FIG. 5 shows changes in the amount of lubricant contained in the lubricant holding member according to the travel distance.
The graph of FIG. 5 compares the case where one sheet-like fiber part is used as a lubricant holding member and the case where two sheets are used in an overlapping manner. Slowly, it can be seen that the lubricant is retained even when the traveling distance becomes long. Thus, in order to maintain the retention amount of the lubricant, it is effective to increase the volume of the fiber component.

  However, if the volume of the member holding the lubricant is simply increased (specifically, the thickness is increased), the thickness of other members will be reduced due to layout restrictions, and the necessary rigidity will not be obtained. Other performance may be affected.

  Accordingly, an object of the present invention is to provide a fixing device capable of preventing the exhaustion of the lubricant to suppress the increase in the friction load and preventing the lubricant from flowing out into the device and improving the life of the device. To do.

  In order to achieve this object, a fixing device according to the present invention includes a rotatable endless fixing sleeve, a heat source for heating the fixing sleeve, a nip forming member disposed inside the fixing sleeve, A pressure roller that forms a nip portion with the fixing sleeve by contacting the nip forming member via the fixing sleeve, and transports a recording medium carrying an unfixed image to the recording medium. In the fixing device for fixing a received image, the nip forming member includes a lubricant holding portion capable of holding a lubricant, and a lubricant discharge portion for discharging the lubricant in the lubricant holding portion to the upstream side in the rotation direction of the fixing sleeve. The fixing sleeve is in contact with the nip forming member via a lubricant at the nip portion and is rotated by a frictional force with the pressure roller as the pressure roller rotates. A fixing device according to claim Rukoto.

  According to the present invention, it is possible to provide a fixing device capable of preventing the exhaustion of the lubricant to suppress the increase in the friction load and preventing the lubricant from flowing out into the device and improving the life of the device. .

It is explanatory drawing which shows one Embodiment of the conventional fixing device. 1 is a configuration diagram illustrating an embodiment of a fixing device of the present invention. 1 is a configuration diagram illustrating an embodiment of an image forming apparatus of the present invention. 6A and 6B are a schematic diagram and a photograph for explaining leakage of lubricant in the fixing device. It is a graph which shows reduction of the lubricant amount of a lubricant holding member. FIG. 2 is a schematic diagram illustrating a main part of an embodiment of a fixing device of the present invention. FIG. 2 is a schematic diagram illustrating a main part of an embodiment of a fixing device of the present invention. It is a schematic diagram showing an example of a nip forming member of the fixing device of the present invention. It is a table | surface which shows the example of a commercially available coating agent.

  Hereinafter, a fixing device and an image forming apparatus according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art, and any aspect is possible. As long as the functions and effects of the present invention are exhibited, the scope of the present invention is included.

[Fixing device]
The fixing device according to the present invention includes a rotatable endless fixing sleeve, a heat source for heating the fixing sleeve, a nip forming member disposed inside the fixing sleeve, and the nip formation via the fixing sleeve. A pressure roller that forms a nip portion with the fixing sleeve by contacting with the member is provided, the recording medium carrying the unfixed image is conveyed, and the unfixed image is fixed on the recording medium.
The nip forming member has a lubricant holding portion capable of holding a lubricant, and a lubricant discharge portion for discharging the lubricant in the lubricant holding portion to the upstream side in the rotation direction of the fixing sleeve, and the fixing sleeve Is brought into contact with the nip forming member via a lubricant at the nip portion, and is rotated by a frictional force with the pressure roller as the pressure roller rotates.

FIG. 2 is a block diagram showing an embodiment of the fixing device of the present invention.
As shown in FIG. 2, the fixing device includes a pressure roller 3 and a fixing sleeve (fixing belt) 1, and the fixing sleeve 1 is directly heated from the inner peripheral side by a heat source 2. Although the heat source 2 is a halogen heater in this embodiment, it is not limited to this, For example, IH, a resistance heating element, a carbon heater, etc. may be sufficient.

In the fixing sleeve 1 of FIG. 2, there is a nip forming member 6 that forms a nip with a pressure roller 3 that is opposed to the fixing sleeve 1, and slides directly on the inner surface of the fixing sleeve.
Although the shape of the nip portion is flat in FIG. 2, it may be a concave shape or other shapes. When the nip has a concave shape, the discharge direction at the leading edge of the recording paper is closer to the pressure roller, so that the separability is improved and the occurrence of jam is suppressed.

  The fixing sleeve 1 is an endless belt (or film) using a metal belt such as nickel or SUS or a resin material such as polyimide. The surface layer of the belt has a release layer such as a PFA or PTFE layer, and has a release property so that toner does not adhere. There may be an elastic layer formed of a silicone rubber layer or the like between the belt substrate and the PFA or PTFE layer. When there is no silicone rubber layer, the heat capacity is reduced and the fixability is improved, but when the unfixed image is crushed and fixed, minute irregularities on the belt surface are transferred to the image, and the image has a crusty skin shape. There arises a problem that the gloss unevenness (zudder skin image) remains. In order to improve this, it is necessary to provide a silicone rubber layer of 100 μm or more. Due to the deformation of the silicone rubber layer, fine irregularities are absorbed and the skin image is improved.

A support member (stay) 7 for supporting the nip portion is provided inside the fixing sleeve 1 to prevent the nip forming member 6 that receives pressure from the pressure roller 3 from bending and to obtain a uniform nip width in the axial direction. I am trying to do it.
The support member 7 is held and fixed to a holding member (flange) 8 at both ends and positioned.

Further, a reflection member 9 is provided between the heat source 2 and the support member 7, and wasteful energy consumption due to the support member 7 being heated by radiant heat from the heat source 2 or the like is suppressed.
Instead of providing the reflection member 9, it is possible to obtain the same effect even if the surface of the support member 7 is heat-insulated or mirror-finished.

The pressure roller 3 has an elastic rubber layer 4 on a cored bar 5 and a release layer (PFA or PTFE layer) on the surface in order to obtain releasability. The pressure roller 3 is rotated by a driving force transmitted through a gear from a driving source such as a motor provided in the image forming apparatus.
The pressure roller 3 is pressed against the fixing sleeve 1 by a spring or the like, and has a predetermined nip width by the elastic rubber layer 4 being crushed and deformed. The pressure roller 3 may be a hollow roller, and the pressure roller 3 may have a heating source such as a halogen heater.
The elastic rubber layer 4 may be solid rubber, but if there is no heater inside the pressure roller 3, sponge rubber may be used. Sponge rubber is more desirable because it increases heat insulation and makes it difficult for heat of the fixing sleeve to be taken away.

The fixing sleeve 1 rotates along with the pressure roller 3.
In the example of FIG. 2, the pressure roller 3 is rotated by a driving source (not shown), and the driving force is transmitted to the belt at the nip portion N, whereby the fixing sleeve 1 is rotated. The fixing sleeve 1 is sandwiched and rotated at the nip portion N, and travels while being guided by the holding member 8 (flange) at both ends except the nip portion.

With the above-described configuration, it is possible to realize a fixing device that is inexpensive and has a fast warm-up.
Hereinafter, as illustrated in FIG. 2, a configuration in which the pressure roller 3 and the fixing sleeve 1 are provided in the fixing device, and the fixing sleeve 1 is directly heated from the inner peripheral side by radiant heat by the heat source 2 will be exemplarily described.

Since the lubricant is a fluid, as shown in FIGS. 4 (A) and 4 (B), leakage as indicated by an arrow 31 from the inside of the fixing sleeve 1 to the region indicated by reference numeral 32 from the end of the nip forming member 6 occurs. Occur.
In contrast, in the fixing device of the present embodiment shown in FIG. 6, the nip forming member 6 has a lubricant holding portion 6 a that can hold the lubricant 30, so that a conventional fiber sheet is provided as the lubricant holding member. The retention amount of the lubricant can be ensured more than the configuration, and the rigidity as the member can be maintained.

Further, the nip forming member 6 has a lubricant discharge portion 6 b that discharges the lubricant 30 to the upstream side in the rotation direction of the fixing sleeve 1. The lubricant 30 is dropped by gravity from the lubricant discharge portion 6b, and the lubricant is applied in the direction indicated by the arrow 30a by the rotation of the fixing sleeve 1. Thereby, a lubricant layer is formed, and a friction state similar to that in which the lubricant holding member impregnated with the lubricant is disposed can be created.
In the case of a conventional fiber-made lubricant holding member, since the thickness is about 0.5 mm, the length is about 300 mm, and the width is about 15 mm, the holding amount of the lubricant is limited to about 1 g. FIG. 4C shows a state in which leakage occurs from the end of the fixing sleeve 1 when the lubricant is 2.28 g.
According to the nip forming member of the present embodiment, it is possible to realize a holding amount exceeding this.

The material of the nip forming member 6 is a member that is disposed near the heater that is the heat source 2 and receives pressure from the pressure roller 3 at the nip portion N. LCP, PAI, PEEK, etc.) are preferred.
When the temperature assumed as a high temperature state caused by continuous paper passing is about 300 ° C., a resin having a deflection temperature under load of about 350 ° C. (for example, LCP, E5006L manufactured by Sumitomo Chemical Co., Ltd.) is appropriate. When a high temperature of 400 ° C. or higher is required, a member made of metal instead of resin may be used.

As shown in FIG. 7, the lubricant discharge portion 6b of the nip forming member 6 preferably has a labyrinth structure 6c.
The labyrinth structure 6c is formed for the purpose of providing an intricate flow path to reduce the leakage of the lubricant. The flow path is bent, so that the resistance increases, the pressure loss increases, and the leakage amount can be reduced. Specifically, in the labyrinth structure 6c, a clearance minimum portion in which the flow path is abruptly reduced is formed in the middle, and the lubricant hardly flows in the clearance minimum portion.

  In the sliding portion between the nip forming member 6 and the fixing sleeve 1, the necessity of the lubricant increases in the process in which the friction increases with time. However, by having the discharge portion of the labyrinth structure, the initial excessive lubricant The supply is suppressed and the lubricant is stably supplied thereafter.

  The nip forming member 6 may not have good slidability of the constituent material. Therefore, the nip forming member 6 may be provided with a sheet member made of a fluororesin fiber at least on the sliding surface with the fixing sleeve 1.

The sheet member made of fluorine resin fiber is provided for improving the slidability, and examples of the fluorine resin fiber include fibrous PTFE, PFA, ETFE and the like.
The sheet member may include a resin fiber other than the fluorine resin fiber. For example, the frictional wear characteristics and strength can be increased by increasing the area of the fluororesin on the friction surface and increasing the area of the resin fiber with high strength or high oil content on the opposite surface. The sheet can be made excellent.
As the sheet member, a resin sheet woven with two fibers of PTFE and PPS (for example, “Toyoflon” manufactured by Toray Industries, Inc.) is preferable because it has an effect of suppressing an increase in torque over time.

  The nip forming member 6 may be coated with at least one of a ceramic coating agent and a fluorine coating agent on the sliding surface with the fixing sleeve 1.

By applying a ceramic or fluorine coating on the surface of the nip forming member 6, the frictional load can be reduced.
PTFE and PFA coatings are often used as slidable coating agents because of their low reactivity with other materials and high heat resistance. For example, commercially available fluorine paints (manufactured by Daikin Industries) shown in the table of FIG. 9 have PFA and PTFE grades depending on the temperature and application.
Ceramic-based coatings are harder and harder to wear than fluorine coatings, and are effective when it is desired to avoid an increase in the viscosity of the lubricant due to coating abrasion.
In addition, fluorine-based coatings have better adhesion to metals than resins. For example, if the heat resistance of the resin is insufficient, or if you want to increase the heat transfer in the axial direction, coat with a metal such as SUS. Is preferred.

When encapsulating the lubricant inside the nip forming member 6, it is necessary to provide a space for the lubricant holding portion 6 a inside the nip forming member 6. However, a three-dimensional blow that creates air by sending air into the mold. Molding has a track record such as LCP and PPS with high heat-resistant temperature, but the process is complicated and there are technical problems, and costs are high.
Therefore, the nip forming member 6 is preferably composed of a plurality of members that can be divided.

As shown in FIGS. 8A and 8B, the structure in which the nip forming member 6 is divided into a plurality of members and assembled can be easily sealed with the lubricant 30 in the nip forming member. It becomes possible.
Since the nip forming member 6 has the highest temperature in the axial center in terms of the output of the heater, the lubricant 30 tends to remain at the end rather than the center. On the other hand, the space volume can be designed so that the central portion of the lubricant 30 that is easily depleted can be held more than the end portion, and the lubricant holding state can be varied in the axial direction. In such a case, a desired structure can be easily formed by dividing the nip forming member 6 into a plurality of members.

  Moreover, it is preferable that a complicated shape like the labyrinth structure 6c is configured by assembling a plurality of members. In particular, as in the snap-fit structure indicated by reference numeral 6d in FIG. 8B, the cost can be reduced by joining the members without using any parts for coupling.

  Since the nip forming member 6 and the fixing sleeve 1 slide in a high temperature environment near the heat source 2, the lubricant 30 used preferably has a high heat resistance temperature, and is either fluorine grease or silicone oil. It is preferable.

Fluorine grease is a lubricant in which a thickener is dispersed in fluorine oil as a base oil to form a gel. Since the viscosity is higher than that of oil, it is effective as a countermeasure against spillage from the sliding portion. Examples of the fluorine grease include “Varielta” and “Knox Lube” manufactured by NOK Kluber.
Since fluorine grease has a high viscosity, it has a characteristic that the viscosity torque becomes large. When speed fluctuation is required with high accuracy such as slipping of the fixing sleeve 1, it is preferable to use a silicone oil having a low viscosity. Examples of the silicone oil include “KF-968-100CS” manufactured by Shin-Etsu Silicone.

  The fixing device of the present invention having the above-described configuration prevents lubricant from depleting over time to suppress an increase in friction load, and prevents leakage of lubricant into the device by reducing leakage. And the life of the apparatus can be improved.

(Image forming device)
A configuration of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG.
The image forming apparatus shown in FIG. 3 is a color printer using a tandem system in which image forming units for forming a plurality of color images are juxtaposed along the belt extending direction, but the present invention is not limited to this system. It is also possible to target not only printers but also copying machines and facsimile machines.

  In FIG. 3, an image forming apparatus 100 includes photosensitive drums 20Y, 20C, 20M as image carriers capable of forming images as images corresponding to colors separated into yellow, cyan, magenta, and black, respectively. A tandem structure with 20 Bk arranged side by side is adopted.

  In the image forming apparatus 100 having the configuration shown in FIG. 3, the visible images formed on the photosensitive drums 20Y, 20C, 20M, and 20Bk face the photosensitive drums 20Y, 20C, 20M, and 20Bk, and are in the direction of arrow A1. A recording sheet S on which an image is superimposed and transferred by performing a primary transfer process on an intermediate transfer member (hereinafter referred to as a transfer belt) 11 using a movable endless belt, and thereafter a recording sheet or the like is used. On the other hand, batch transfer is performed by executing a secondary transfer process.

  Around each photosensitive drum, an apparatus for image formation processing is arranged according to the rotation of the photosensitive drum. Now, the photosensitive drum 20Bk that performs black image formation will be described as an object. A charging device 30Bk, a developing device 40Bk, a primary transfer roller 12Bk, and a cleaning device 50Bk that perform image forming processing along the rotation direction are arranged. For writing performed after charging, an optical writing device 88 is used.

  In the superimposing transfer to the transfer belt 11, the visible image formed on each photoconductive drum 20 </ b> Y, 20 </ b> C, 20 </ b> M, 20 </ b> Bk is transferred to the same position on the transfer belt 11 in the process of moving the transfer belt 11 in the A1 direction. As described above, voltage application by the primary transfer rollers 12Y, 12C, 12M, and 12Bk disposed to face the respective photosensitive drums 20Y, 20C, 20M, and 20Bk with the transfer belt 11 interposed therebetween causes the A1 direction upstream. The timing is shifted toward the downstream side.

  The photosensitive drums 20Y, 20C, 20M, and 20Bk are arranged in this order from the upstream side in the A1 direction. Each of the photosensitive drums 20Y, 20C, 20M, and 20Bk is provided in an image station for forming yellow, cyan, magenta, and black images.

  The image forming apparatus 100 is disposed so as to face four image stations that perform image forming processing for each color and above each of the photosensitive drums 20Y, 20C, 20M, and 20Bk, and includes a transfer belt 11 and a primary transfer roller 12Y. , 12C, 12M, 12Bk, a transfer belt unit 91 provided opposite to the transfer belt 11, a secondary transfer roller 85 that is a transfer roller as a transfer member that is driven by the transfer belt 11 and rotates. An intermediate transfer belt cleaning device 13 disposed opposite to the transfer belt 11 for cleaning the transfer belt 11, and an optical writing device 88 as an optical writing device disposed below these four image stations. And have.

  The optical writing device 88 is equipped with a semiconductor laser as a light source, a coupling lens, an fθ lens, a toroidal lens, a folding mirror, a rotary polygon mirror as a deflecting means, and the like, and each photosensitive drum 20Y, 20C, 20M, Writing light Lb corresponding to each color with respect to 20 Bk (in the figure, a sign is given only for the image station of the black image, but the same applies to the other image stations) and the photosensitive drums 20Y, 20Y, An electrostatic latent image is formed on 20C, 20M, and 20Bk.

  The image forming apparatus 100 includes a sheet feeding device 61 as a sheet feeding cassette on which recording sheets S transported between the photosensitive drums 20Y, 20C, 20M, and 20Bk and the transfer belt 11 are stacked, and a sheet feeding device. The transfer section between each of the photosensitive drums 20Y, 20C, 20M, and 20Bk and the transfer belt 11 is fed with the recording sheet S conveyed from the feeding device 61 at a predetermined timing in accordance with the toner image formation timing by the image station. And a sensor roller (not shown) for detecting that the leading edge of the recording paper S has reached the registration roller pair 84.

  The image forming apparatus 100 includes the fixing device 10 of the present invention as a roller fixing type fixing unit for fixing the toner image on the recording paper S onto which the toner image is transferred, and the fixing recording paper S to the image forming apparatus. A paper discharge roller 87 that discharges to the outside of the main body of the image forming apparatus 100, and a paper discharge tray that is disposed above the main body of the image forming apparatus 100 and that stacks the recording paper S discharged to the outside of the main body of the image forming apparatus 100 by the paper discharge roller 87. And toner bottles 90Y, 90C, 90M, and 90Bk, which are located below the paper discharge tray and filled with toner of each color of yellow, cyan, magenta, and black.

The transfer belt unit 91 includes a drive roller 72 and a driven roller 73 around which the transfer belt 11 is wound, in addition to the transfer belt 11 and the primary transfer rollers 12Y, 12C, 12M, and 12Bk.
The driven roller 73 also has a function as a tension urging unit for the transfer belt 11. For this reason, the driven roller 73 is provided with an urging unit using a spring or the like. Such a transfer belt unit 91, the primary transfer rollers 12Y, 12C, 12M, and 12Bk, the secondary transfer roller 85, and the cleaning device 13 constitute a transfer device 71.

  The sheet feeding device 61 is disposed at the lower part of the main body of the image forming apparatus 100 and includes a feeding roller 83 as a feeding roller that comes into contact with the upper surface of the uppermost recording sheet S. The uppermost recording sheet S is fed toward the registration roller pair 84 by being driven to rotate counterclockwise 83.

  Although not shown in detail, the cleaning device 13 provided in the transfer device 71 has a cleaning brush and a cleaning blade disposed so as to face and contact the transfer belt 11. The transfer belt 11 is cleaned by scraping and removing foreign matter such as residual toner on the top with a cleaning brush and a cleaning blade.

The cleaning device 13 also has a discharge means (not shown) for carrying out and discarding the residual toner removed from the transfer belt 11.

DESCRIPTION OF SYMBOLS 1 Fixing sleeve 2 Heat source 3 Pressure roller 4 Elastic body 5 Metal core 6 Nip forming member 6a Lubricant holding part 6b Lubricant discharge part 6c Labyrinth structure 7 Support member 8 Holding member 9 Reflecting member 10 Fixing device 30 Lubricant 100 Image formation Device N Nip part

JP 2007-334205 A Japanese Patent No. 5042069 JP 2006-317770 A JP 2003-057978 A Japanese Patent No. 4869440

Claims (7)

By contacting the nip forming member through the fixing sleeve, a rotatable endless fixing sleeve, a heat source for heating the fixing sleeve, a nip forming member disposed inside the fixing sleeve, and the nip forming member. A fixing device that includes a pressure roller that forms a nip portion with a fixing sleeve, conveys a recording medium carrying an unfixed image, and fixes the unfixed image on the recording medium;
The nip forming member has a lubricant holding part capable of holding a lubricant, and a lubricant discharge part for discharging the lubricant in the lubricant holding part to the upstream side in the rotation direction of the fixing sleeve,
The fixing sleeve is in contact with the nip forming member via a lubricant at a nip portion, and is rotated by a frictional force with the pressure roller as the pressure roller rotates. apparatus.   The fixing device according to claim 1, wherein the lubricant discharge portion of the nip forming member has a labyrinth structure.   The fixing device according to claim 1, wherein the nip forming member is provided with a sheet member made of a fluorine resin fiber at least on a sliding surface with the fixing sleeve.   The fixing device according to claim 1, wherein the nip forming member has at least one of a ceramic coating agent and a fluorine coating agent applied to a sliding surface with the fixing sleeve.   The fixing device according to claim 1, wherein the nip forming member includes a plurality of members that can be divided.   6. The fixing device according to claim 1, wherein the lubricant is any one of fluorine grease and silicone oil.   An image forming apparatus comprising the fixing device according to claim 1.