JP2017167313A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device that is directed both to increase the number of sheets continuously fed and prevent slippage of a fixing sleeve with time with a low-friction and high-heat resistant configuration, and an image forming apparatus using the same.SOLUTION: A fixing sleeve 1 arranged opposite to a pressure roller 3 comprises therein a heat source 2, a nip forming member 6, and a support member 7; the nip forming member 6 is in contact with the pressure roller 3 at a nip part N with a lubricant therebetween; the fixing sleeve 1 is co-rotated with the pressure roller 3 by a frictional force from the pressure roller 3. In a start-up operation in a low-temperature environment, or in a normal-temperature environment with time, a fixing device determines if paper can be fed from a preheating temperature of the nip part N. A preheating time for preheating the nip part N is changed according to the travel distance of the fixing sleeve 1 or the travel distance of the pressure roller 3 while a power supplied to the heat source 2 is limited.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fixing device used in an electrostatic recording image forming apparatus such as a copying machine, a facsimile machine, and a printer, and an image forming apparatus equipped with such a fixing device.

  In the above-described fixing device, more specifically, a fixing device that forms a nip between an endless fixing member and a pressure member, and performs a fixing process on a fixing material passing through the nip, the fixing member and the pressure member As the recording medium passes through the formed fixing nip, the toner carried on the recording medium is melted and pressurized to fix the toner image on the recording medium. In recent years, market demands for energy saving and high speed have been increasing for such image forming apparatuses such as printers, copiers, and facsimiles.

  In the image forming apparatus as described above, an unfixed toner image is transferred to a recording material sheet, printing paper, photosensitive paper, electrostatic paper by an image transfer method or a direct method by an image forming process such as electrophotographic recording, electrostatic recording, or magnetic recording. It is formed on a recording material such as recording paper. 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 examples of such a fixing device, a belt-type fixing device (for example, see Patent Document 1) and a surf fixing (film fixing) fixing device (for example, see Patent Document 2) using a ceramic heater are 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 from the completion of printing preparation until the completion of paper discharge after printing operation (referred to as problem 1). Further, as the speed of the image forming apparatus increases, the number of sheets to be passed per unit time increases and the required heat amount increases, so that there is a problem that the heat amount is insufficient (so-called temperature drop) particularly at the beginning of continuous printing. (Referred to as issue 2).

  As a method for solving the problem of the problem 1, surf fixing using a ceramic heater has been proposed. With this method, it is possible to reduce the heat capacity and reduce the size as compared with a belt-type fixing device. However, since only the nip portion is locally heated, the other portions are not heated, and the belt is in the coldest state at the entrance of the nip paper and the like. . In particular, in a high-speed machine (because the rotation of the belt is fast and the heat radiation of the belt outside the nip portion increases), there is a problem that a fixing defect is more likely to occur (referred to as problem 3).

  In order to solve the above problems 1 to 3, in the configuration using an endless belt, the entire belt can be heated, the first print time from the heating standby time can be shortened, and at the time of high-speed rotation There has been proposed a fixing device that solves the shortage of heat and can obtain good fixing properties even when mounted in a high-production image forming apparatus. (For example, patent document 3).

  FIG. 1 is a schematic view of a fixing device described in Patent Document 3. A pipe-shaped metal heat conductor 20 is fixed inside the endless belt 10 so as to be able to guide the movement of the endless belt 10, and endlessly passed through the metal heat conductor 20 by a heat source 30 in the metal heat conductor 20. The belt 10 is heated. Further, a pressure roller 40 that forms a nip portion N in contact with the metal heat conductor 20 via the endless belt 10 is provided, and the endless belt 10 is moved in the circumferential direction so as to rotate as the pressure roller 40 rotates. Let 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. The pressure roller 40 includes an elastic layer 60 on the outer periphery of the metal roller 50.

  In order to further save energy and improve the first print time, a configuration has been proposed in which the endless belt is heated indirectly via a metal heat conductor and the endless belt is heated directly (without a metal heat conductor). Yes. In this configuration, it is possible to realize a reduction in power consumption by greatly improving the heat transfer efficiency and further shortening the first print time from the heating standby time.

  In addition, as a method for further improving the thermal efficiency for energy saving and first print time improvement, the endless belt is heated indirectly through a metal heat conductor, and the endless belt (without using a metal heat conductor). ) Direct heating arrangements have been proposed. However, the heat generated from the fixing heater during continuous sheet passing is stored in the fixing device, and the endless belt is controlled to the toner fixing temperature, but the member inside the endless belt has no member that absorbs heat like toner. Also, there was a problem of high temperature because the structure for dissipating heat was not used. In consideration of the normal high temperature, the fixing member is made of a resin (PEEK, LCP, etc.) having a high heat resistant temperature. For example, in Patent Document 4, Patent Document 5, and the like, a heat-resistant resin is provided with a slidable coating so as to have a role of securing rigidity at a high temperature as a stay and a role of a friction structure that reduces torque. . Patent Document 6 proposes a structure in which a SUS metal sheet is wound around a stay member, and in any case, it has a role of a friction structure that ensures rigidity and low torque.

  However, when a large number of continuous sheets are required, the periphery of the stay is exposed to a high temperature of 300 ° C. or higher. For example, a support member 7 shown in FIG. The heat resistance temperature of 6 is exceeded. Then, thermal deformation or melting may occur at the portion where the support member 7 and the nip forming member 6 are in contact with each other.

  SUMMARY OF THE INVENTION In view of the above points, the present invention provides a fixing device configured to simultaneously improve the number of continuously passing sheets with a low friction and high heat resistance configuration and prevent slipping with time, and an image forming apparatus using the same. With the goal.

  In the fixing device according to the present invention, the fixing sleeve opposed to the pressure roller includes a heat source and a base member inside, and the base member contacts the pressure roller via a lubricant at a nip portion, and The fixing sleeve is rotated by the frictional force from the pressure roller, and when starting up in a low temperature environment or in a room temperature environment over time, a judgment is made as to whether or not the sheet can pass through the preheating temperature of the nip portion. The fixing device is characterized in that the preheating time of the nip portion is changed according to a travel distance in a state where power supplied to the heat source is limited.

  According to the present invention, by reducing the viscosity of the lubricant, it is possible to prevent slipping in a low temperature environment over time.

FIG. 10 is a conceptual cross-sectional view illustrating a configuration of a conventional fixing device. 1 is a cross-sectional view illustrating an example of a fixing device that is an object of the present invention. FIG. 2 is a schematic diagram for explaining a configuration of an image forming apparatus using a fixing device according to the present invention. It is a figure which shows the graph showing the relationship between the friction load in the state which apply | coated the lubricant to the base member, and temperature. FIG. 5 is a diagram illustrating a nip temperature, a slip ratio of a fixing sleeve, and a state of a lubricant solidified at a low temperature. FIG. 6 is a diagram illustrating an example of a state in which a dent is generated due to an increase in thermal stress due to an excessive amount of heat to the fixing sleeve. It is a flowchart which performs electric power restriction | limiting by a travel distance, sets a heater heating time, and passes a paper. It is a perspective view which shows the example from which a screw, screwing components, etc. become unnecessary in the nip formation member periphery structure conventionally produced with resin. It is a figure which shows the table | surface of fluorine grease evaporation amount. It is a figure which shows the table | surface (A) of melting | fusing point and continuous useable temperature of each resin of Fluon (trademark), and the table | surface (B) which shows the relationship between the number of assumption paper passing and Ni + PTFE coat thickness. It is a figure which shows the setting of the heating time T according to travel distance.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 2 is a cross-sectional view illustrating a configuration of an example of a fixing device that is an object of the present invention. The fixing device shown in the figure has a pressure rotating body (pressure roller 3 in the case of FIG. 2) and a fixing sleeve 1, and the fixing sleeve 1 is arranged on the inner peripheral side by a heat source 2 (for example, a halogen heater in FIG. 2). Heated directly from.

  At this time, in the fixing sleeve 1, a nip forming member 6 that forms a nip with the pressure roller 3 opposed via the fixing sleeve 1 is arranged together with the support member 7. The nip forming member 6 slides directly (or indirectly through a sliding sheet (not shown)) on the inner surface of the endless belt-like fixing sleeve 1. In the example of FIG. 2, the shape of the nip portion N is flat, but may be a concave shape or other shapes. When the nip portion N has a concave shape, the discharge direction of the leading end of the recording paper is closer to the pressure roller, and the separation is improved, so that the occurrence of jam can be suppressed.

  The fixing sleeve 1 is a metal belt such as nickel or SUS or an endless belt (or film) using 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 7 (a stay-like member in the illustrated example) that is a base member for supporting the nip portion N is provided inside the fixing sleeve 1, and the nip forming member 6 that receives pressure from the pressure roller 3 is bent. This prevents a uniform nip width in the axial direction. The support member 7 is held and fixed to the holding member 8 (flange) 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. Here, the same effect can be obtained even if the surface of the support member 7 is heat-insulated or mirror-finished instead of having the reflecting member 9.

  The heat source 2 may be the halogen heater described above, but may be IH, a resistance heating element, a carbon heater, or the like.

  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 the fixing belt to lose heat.

  The fixing sleeve 1 rotates along with the pressure roller 3. In the case 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 configuration, it is possible to realize a fixing device that is inexpensive and has a fast warm-up.

Next, the configuration of the image forming apparatus using the above-described configuration will be described with reference to FIG.
The image forming apparatus shown in FIG. 3 is a color printer that uses a tandem system in which image forming units for forming a plurality of color images are juxtaposed along the belt extending direction. However, the present invention is not limited to the image forming apparatus according to this method, and can be applied not only to a printer but also to a copying machine, a facsimile machine, and the like.

  The image forming apparatus 100 in FIG. 3 includes photosensitive drums 20Y, 20C, 20M as image carriers that can form 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. Visible images are formed on the photosensitive drums 20Y, 20C, 20M, and 20Bk. A primary transfer process is performed on an intermediate transfer body (hereinafter referred to as a transfer belt) 11 that uses an endless belt that can move in the direction of the arrow A1 while facing the photosensitive drums 20Y to 20Bk. Then, the images of the respective photoconductive drums 20Y to 20Bk are superimposed and transferred. Thereafter, the recording sheet S using the recording sheet or the like is transferred in a batch by executing a secondary transfer process.

  Around each of the photosensitive drums 20Y, 20C, 20M, and 20Bk, an apparatus for image forming processing is arranged according to the rotation of the photosensitive drum. Now, the photosensitive drum 20Bk that performs black image formation will be described. The charging device 30Bk, the developing device 40Bk, the primary transfer roller 12Bk, and the cleaning device 50Bk that perform image forming processing along the rotation direction of the photosensitive drum 20Bk are described. Has been placed. For the writing performed after charging, the optical writing device 80 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. Is done. As described above, voltage application by the primary transfer rollers 12Y, 12C, 12M, and 12Bk arranged to face the 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, respectively.

  The image forming apparatus 1000 is disposed so as to face four image stations that perform image forming processing for each color, and above the photosensitive drums 20Y, 20C, 20M, and 20Bk. The transfer belt unit 110 includes the transfer belt 11 and the primary transfer rollers 12Y, 12C, 12M, and 12Bk, and a transfer member that is disposed opposite to the transfer belt 11 and that is driven by the transfer belt 11 and rotates. A secondary transfer roller 51 which is a transfer roller is provided. Also, a cleaning device 13 disposed to face the transfer belt 11 to clean the surface of the transfer belt 11, and an optical writing device 80 as an optical writing device disposed to face below the four image stations. have.

  The optical writing device 80 is equipped with a semiconductor laser as a light source, a coupling lens, an fθ lens, a toroidal lens, a folding mirror, a rotating polygon mirror as a deflecting means, and the like. Then, writing light Lb corresponding to each color is emitted to each of the photosensitive drums 20Y to 20Bk to form an electrostatic latent image on the photosensitive drums 20Y, 20C, 20M, and 20Bk. In FIG. 3, for the sake of convenience, the symbol Lb is attached only to the image station of the black image, but the same applies to the other image stations.

  The image forming apparatus 1000 includes a sheet feeding device 61 as a paper feeding cassette on which the recording paper S transported between the photosensitive drums 20Y, 20C, 20M, and 20Bk and the transfer belt 11 is stacked. In addition, the recording sheet S conveyed from the sheet feeding device 61 is transferred between the photosensitive drums 20Y to 20Bk and the transfer belt 11 at a predetermined timing in accordance with the toner image formation timing by the image station. A registration roller pair 41 that is fed out toward the front. Further, a sensor (not shown) for detecting that the leading edge of the recording paper S has reached the registration roller pair 41 is provided.

  The image forming apparatus 1000 includes a fixing device 120 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 main body of the image forming apparatus 1000 with the fixed recording paper S And a paper discharge roller 75 for discharging to the outside. In addition, a paper discharge tray 17 is provided which is disposed on the top of the main body of the image forming apparatus 1000 and stacks the recording paper S discharged to the outside of the main body of the image forming apparatus 1000 by a paper discharge roller 75. In addition, toner bottles 9Y, 9C, 9M, and 9Bk are provided below the paper discharge tray 17 and filled with toners of yellow, cyan, magenta, and black.

  In addition to the transfer belt 11 and primary transfer rollers 12Y, 12C, 12M, and 12Bk, the transfer belt unit 110 includes a driving roller 72 and a driven roller 73 around which the transfer belt 11 is wound.

  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 110, the primary transfer rollers 12Y, 12C, 12M, and 12Bk, the secondary transfer roller 51, 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 1000. A feeding roller 31 is provided as a sheet feeding roller in contact with the upper surface of the uppermost recording sheet S, and the feeding roller 31 is driven to rotate counterclockwise. As a result, the uppermost recording sheet S is fed toward the registration roller pair 41.

  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. Then, the transfer belt 11 is cleaned by scraping and removing foreign matters such as residual toner on the transfer belt 11 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.

  Hereinafter, the fixing device has a pressure rotating body (pressure roller 3 in the case of FIG. 2) and a fixing sleeve 1, and the heat source 2 (for example, a halogen heater in FIG. 2) causes the fixing sleeve 1 to radiate heat from the inner peripheral side. An example of a structure that is directly heated will be described.

<Embodiment 1>
The fixing sleeve 1 facing the pressure roller 3 is in contact with the nip forming member 6 inside the fixing sleeve 1 via the lubricant at the nip portion N, and the frictional force from the pressure roller 3 that is rotationally driven by the motor. To rotate. In this configuration, since the fixing sleeve 1 does not have a drive source, the fixing sleeve 1 may not rotate and the paper may jam if the friction load inside the fixing sleeve 1 is large. In particular, the degree of deterioration of the lubricant that causes the friction load on the inner surface of the fixing sleeve 1 is greatly affected. Generally, a lubricant has a high viscosity at a low temperature and a low viscosity at a high temperature.

  FIG. 4 is a graph showing the relationship between the friction load and the temperature in a state where the lubricant is applied to the base member. The relationship is in an inverse proportion such that the friction load decreases as the temperature increases, and the friction load can be reduced by increasing the temperature. In addition, the lubricating performance of the lubricant deteriorates over time due to evaporation of base oil components, oxidation, and contamination. Especially in high temperature environment, the degree of deterioration becomes large, and as shown in FIG. 9, in the case of fluorine grease, the evaporation of the base oil component is more than twice in the high temperature environment of 200 ° C. or higher compared to the case of high temperature of 200 ° C. or lower. become. For example, when the melting point of the toner is high or when a large amount of printing is continuously performed, the time during which the support member 7 and the nip forming member 6 are exposed to a high temperature becomes long and rises to 300 ° C. or more, greatly affecting the machine life. Therefore, when starting up in a low temperature environment, the nip portion N is warmed to some extent to keep the viscosity of the lubricant low, and if the pre-heated state is passed so that the fixing sleeve 1 does not slip, the slip jam is suppressed. it can.

  FIG. 5 is a diagram showing the nip temperature, the slip ratio of the fixing sleeve, and the state of the lubricant solidified at a low temperature. The slip ratio indicates how much the fixing sleeve 1 is driven with respect to the rotation speed of the pressure roller 3 (slip ratio 0%..., The fixing sleeve 1 and the pressure roller 3 have the same linear speed and slip. Ratio 50%: The fixing sleeve 1 has a linear speed that is half the linear speed of the pressure roller 3). When the slip ratio is large, a rubbing image or the like is generated due to the occurrence of jam or contact with peripheral members due to sagging, so 0% is preferable. However, if the jam or abnormal image does not occur, the preheating state temperature having an effect of suppressing the slip by dissolving the lubricant solidified at a low temperature may be slipped. It can be changed and set according to the type of lubricant and the state of applied pressure.

  In addition, as described above, the viscosity due to the deterioration of the lubricant increases as time passes even in a room temperature environment, so slippage can be prevented by shifting to a preheated state and passing paper.

<Embodiment 2>
In the transition to the nip preheating state, the heater is heated before passing the paper, but at that time, if the fixing sleeve 1 slips and rotates little, the thermal stress increases due to excessive heat amount to the fixing sleeve 1 as shown in FIG. A dent occurs. In particular, even if slip does not occur in the initial state, slip occurs in a state of deterioration with time. Therefore, in order to prevent such a state, the nip preheating state may be shifted to a state where the power is limited to such an extent that an excessive amount of heat does not occur to the fixing sleeve 1 even when the fixing sleeve 1 slips immediately after startup. It is valid.

  FIG. 7 shows a flow chart in which the power is limited by the travel distance, the heater heating time is set, and the paper is passed. In the initial state where no slip occurs, the nip portion N is heated without any power limitation. However, as the travel distance increases, the lubricant deteriorates, and the fixing sleeve 1 starts to slip. The degree of slip increases as the travel distance increases, and the time for raising the nip portion N to the preheated state in a state where the electric power is limited becomes longer. As shown in FIG. 11, the heating time is increased as the distance increases at the beginning of traveling at the heating time of 0 s. The heating time can be changed and set according to the machine life setting, set temperature, lubricant type and pressurizing condition. By such control, it is possible to maintain stable conveyance quality without slipping over time. it can.

<Embodiment 3>
Since the sliding is performed in a high temperature environment near the heater, fluorine grease or silicone oil having a high heat resistance temperature is suitable as the lubricant. Fluorine grease is a lubricant in which a thickener is dispersed in fluorine oil, which is the base oil, and is in the form of a gel. Since its viscosity is higher than oil, it is effective as a countermeasure against spills from sliding parts. , Knox Lube etc. Fluorine grease is characterized by a high viscosity torque due to its high viscosity. When high-precision control that does not cause speed fluctuation such as slip of the fixing sleeve 1 is required, it is appropriate to use silicone oil having a high heat-resistant temperature and low viscosity like fluorine grease. For this purpose, KF-968-100CS made by Shin-Etsu Silicone is used. Increase in friction load in high temperature environment can be suppressed.

<Embodiment 4>
It is effective to wind a fluorinated sheet having good slidability around the nip forming member 6 to reduce the sliding load on the inner surface with the fixing sleeve 1. As a sheet-like resin fiber, a fluorine-based resin is excellent in friction and wear characteristics, and PTFE, PFA, and ETFE are commercialized in a fibrous form. The fibrous sheet can infiltrate the lubricant and prevent outflow. As shown in FIG. 8, a slidable sheet (not shown) is wound around the nip forming member 6 (arrow A), The sliding sheet is attached to the nip forming member 6 by screwing (arrow B) so that it can be used.

  The sheet-like fiber has a different thread area on the surface depending on the weaving method. The plain weave has the same area ratio on the surface of the warp and weft, but the twill or satin weave has more surface area on the surface than the weft. When knitting two or more types of fibers, increase the area of the fluororesin in the part that becomes the friction surface, and increase the area of the resin that has high strength or high oil content in the part that becomes the back surface. The sheet has good friction and wear characteristics and high strength. Toyoflon manufactured by Toray is a resin sheet in which two fibers of PTFE and PPS are woven, and can suppress an increase in torque over time.

<Embodiment 5>
The base member may not have good slidability depending on the material, and it is appropriate to apply a ceramic or fluorine coating to reduce the frictional load on the surface. Fluorine-based PTFE and PFA coatings are often used as slidable fluorine coatings because of their low reactivity with other materials and high heat resistance. For example, the Daikin Industries fluorine paint shown in FIG. 10 has PFA and PTFE grades depending on temperature and application.

  Ceramic coating is harder and harder to wear than fluorine coating, and is effective when you want 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, you can coat the metal such as SUS. Is optimal.

  In addition, as shown in FIG. 8, there is no need for screws and screwing parts for fixing the nip forming member made of conventional resin and the peripheral members, and the number of parts can be greatly reduced and the cost can be reduced. Become. That is, by suppressing the surface abrasion of the base member and reducing the friction, the torque can be suppressed by reducing the load of the surface layer friction of the base member.

  The present invention is not limited to the embodiments described above, and many variations are possible by those having ordinary knowledge in the art within the technical idea of the present invention.

1: fixing sleeve 2: heat source 3: pressure roller 4: elastic rubber layer 5: core metal 6: nip forming member 7: support member 8: holding member 9: reflecting member 100: image forming apparatus 110: transfer belt unit 120: Fixing apparatus 1000: Image forming apparatus N: Nip portion

JP 2004-286922 A Japanese Patent No. 2861280 JP 2007-334205 A JP 2006-317770 A JP 2003-057978 A Japanese Patent No. 4869440

Claims (5)

The fixing sleeve facing the pressure roller includes a heat source and a base member inside,
The base member is in contact with the pressure roller via a lubricant at the nip portion;
The fixing sleeve is rotated by the frictional force from the pressure roller,
At the time of start-up operation in a low temperature environment, or in a normal temperature environment over time, a judgment is made as to whether paper can be passed by the preheating temperature of the nip part.
A fixing device,
The preheating time of the nip portion is changed according to the travel distance in a state where power supplied to the heat source is limited.
A fixing device. The lubricant is fluorine grease or silicone oil,
The fixing device according to claim 1. The base member includes a fluorine-based fiber resin,
The fixing device according to claim 1, wherein The base member has a ceramic or fluorine coating,
The fixing device according to claim 1, wherein the fixing device is a fixing device. An image forming apparatus comprising the fixing device according to claim 1.