JP2017167460A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of obtaining excellent heating efficiency, while maintaining the stable travel of a fixing member.SOLUTION: A fixing device 100 includes a fixing belt 101, two halogen heaters 102A and 102B which heat the fixing belt 101 in a non-nip part, a nip forming member 106 which is arranged on the inner peripheral side of the fixing belt 101, and a pressure roller 103 which presses a paper sheet P toward the side of the fixing belt 101. A heat transfer auxiliary member 116 for assisting heat transfer in the longitudinal direction of the fixing belt 101 in a nip part N is provided on the side of the fixing belt 101 of the nip forming member 106. Two end heaters 126a and 126b which heat the vicinities of both ends of the fixing belt 101 in the nip part are provided at longitudinal both ends between the nip forming member 106 and the heat transfer auxiliary member 116. The respective contact parts with the respective end heaters 126a and 126b of the heat transfer auxiliary member 116 can be deformed by a stress smaller than a pressing force by the pressure roller 103.SELECTED DRAWING: Figure 2

Description

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

Conventionally, a nip portion is formed between an endless fixing member such as a fixing belt and a pressing member such as a pressure roller, and heat and pressure are applied to the recording material passing through the nip portion, and the image is not fixed on the recording material. There is known an image forming apparatus including a contact heating type fixing device for fixing the toner image.
For example, Patent Document 1 describes an image forming apparatus (color printer) including the following fixing device.

A rotatable endless fixing member, a heating means for heating the fixing member at a non-nip portion, a nip forming member disposed on the inner peripheral side of the fixing member, and a recording material sandwiched and conveyed by the fixing member. A pressing member that presses toward the side, and an end heat source that heats the vicinity of both ends of the fixing member at the nip portion.
An end heat source that heats the vicinity of both ends of the fixing member is pressed against and brought into contact with the inner peripheral surface of the fixing member in the nip portion by an urging means.
By configuring the fixing device in this way, Patent Document 1 discloses that even a large size paper such as A3 Novi can be efficiently used without consuming wasteful energy with a simple configuration and without reducing productivity. It is described that it is possible to provide a fixing device that can be used.

  However, in the configuration including the conventional end heat source, if the contact pressure of the end heat source with respect to the fixing member is increased in order to increase the heat transfer efficiency from the end heat source to the fixing member, the friction between the end heat source and the fixing member is increased. This may increase the force and cause the running failure of the fixing member. On the other hand, if the contact pressure of the end heat source with respect to the fixing member is reduced in order to suppress the occurrence of poor running, the contact between the end heat source and the fixing member tends to become unstable, resulting in poor heat transfer to the fixing member. Heating efficiency may decrease.

  In order to solve the above-described problems, the invention described in claim 1 is directed to a rotatable endless fixing member, heating means for heating the fixing member at a non-nip portion, and an inner peripheral side of the fixing member. A nip forming member that is disposed; a pressing member that presses the recording material that is nipped and conveyed by the fixing member toward the fixing member; an end heat source that heats the vicinity of both ends of the fixing member at the nip portion; A heat transfer auxiliary member for assisting heat transfer in the longitudinal direction of the fixing member at a nip portion formed between the fixing member and the pressing member on the fixing member side of the nip forming member. And providing the end heat sources at both ends in the longitudinal direction between the nip forming member and the heat transfer auxiliary member, and the contact portion of the heat transfer auxiliary member with the end heat source is pressed by the pressing member. Less than pressure In characterized in that the deformable structure.

  According to the present invention, it is possible to provide a fixing device capable of obtaining good heating efficiency while maintaining stable running of the fixing member.

1 is a schematic configuration diagram of a printer according to an embodiment. FIG. FIG. 3 is a schematic explanatory diagram of a fixing device. Explanatory drawing of the prior art example of the fixing device of 2 halogen heater structure. FIG. FIG. 4 is a perspective explanatory view of a nip forming portion provided in the fixing device. FIG. 3 is an explanatory diagram of a positional relationship in the longitudinal direction between each heater provided in the fixing device and a sheet to be fixed. FIG. 4 is an explanatory diagram of a positional relationship in the longitudinal direction of each heater in the vicinity of both ends provided in the fixing device. FIG. 4 is an explanatory diagram of a positional relationship between heaters and end temperature detection means in the vicinity of both ends provided in the fixing device. Side surface explanatory drawing of the heat transfer auxiliary member of Example 1. FIG. Sectional explanatory drawing of the contact part of the heat transfer auxiliary member 116 of Example 1, and the left end part heater and right end part heater which are edge part heat sources. Side surface explanatory drawing of the heat transfer auxiliary member of Example 2. FIG. Side surface explanatory drawing of the heat transfer auxiliary member of Example 3. FIG. Explanatory drawing of distribution of the longitudinal direction of the applied pressure (pressing force) by a pressure roller. Side surface explanatory drawing of the heat transfer auxiliary member of Example 4. FIG.

Hereinafter, an embodiment of an electrophotographic color printer (hereinafter referred to as a printer 200) will be described as an image forming apparatus including a fixing device to which the present invention is applied.
FIG. 1 is a schematic configuration diagram of a printer 200 according to the present embodiment.
The printer 200 shown in FIG. 1 is a tandem type color printer in which image forming units for forming a plurality of color images are juxtaposed along the extending direction of a transfer belt 11 as an intermediate transfer member. However, the image forming apparatus to which the fixing device of the present embodiment can be applied is not limited to this method, and can be applied not only to a printer but also to an image forming apparatus such as a copying machine or a facsimile machine.

The printer 200 is a tandem in which photosensitive drums 20Y, 20C, 20M, and 20B as image carriers that can form images corresponding to colors separated into yellow, cyan, magenta, and black are arranged in parallel. Structure is adopted.
In the printer 200, the transfer belt 11 is an endless belt in which a visible image formed of a toner image formed on each photoconductive drum 20Y, C, M, Bk can move in the direction of arrow A1 while facing the photoconductive drum. Primary transfer. By executing this primary transfer process, the images of the respective colors are superimposed and transferred, and then transferred to the sheet P, which is a sheet-like recording material, by performing a secondary transfer process.

  Around each photosensitive drum 20, an apparatus for image forming processing is arranged according to the rotation of the photosensitive drum 20. The photosensitive drum 20Bk that performs black image formation will be described as a representative. 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 arranged. Has been. The optical writing device 8 is used for optical writing using the writing light Lb performed after uniform charging by the charging device 30Bk.

  In the superimposing transfer on the transfer belt 11, the toner images formed on the photosensitive drums 20 </ b> Y, 20 </ b> C, 20 </ b> M, and Bk are overlapped at the same position on the transfer belt 11 in the process in which the transfer belt 11 moves in the direction A <b> 1. Is transcribed. For this reason, the primary transfer is performed by applying a voltage from the primary transfer rollers 12Y, 12C, 12M, and 12B that are disposed to face the photosensitive drums 20Y, 20C, 20M, and 20B with the transfer belt 11 interposed therebetween. The timing is shifted from the upstream side toward the downstream side in the A1 direction.

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

  The printer 200 is disposed so as to face four image stations that perform image formation processing for each color, and above the respective photosensitive drums 20Y, 20C, 20M, 20B, 20K, and transfer belts 11 and primary transfer rollers 12Y, 12C, and 12K. A transfer belt unit 10 having M and Bk is provided. There are also a secondary transfer roller 5 that is disposed facing the transfer belt 11 and is driven by the transfer belt 11, and a belt cleaning device 13 that is disposed facing the transfer belt 11 and cleans the transfer belt 11. I have. The optical writing device 8 is also provided so as to face the lower side of the four image stations.

  The optical writing device 8 is equipped with a semiconductor laser as a light source for writing an electrostatic latent image, a coupling lens, an fθ lens, a toroidal lens, a folding mirror, a rotating polygon mirror as a polarizing means, and the like. This optical writing device 8 emits writing light Lb corresponding to each color to each photosensitive drum 20Y, C, M, Bk to form an electrostatic latent image on the photosensitive drum 20Y, C, M, Bk. It is configured to In FIG. 1, for the sake of convenience, the writing light Lb is labeled only for the image station of the black image, but the same applies to the other image stations.

  The printer 200 is provided with a sheet feeding device 61 as a sheet feeding cassette on which sheets P conveyed between the transfer belt 11 and the secondary transfer roller 5 are stacked. In addition, the sheet P conveyed from the sheet feeding device 61 is transferred to the secondary transfer portion between the transfer belt 11 and the secondary transfer roller 5 at a predetermined timing in accordance with the toner image formation timing by the image station. A pair of registration rollers 4 that is fed out is provided. Further, a sensor for detecting that the leading edge of the paper P has reached the registration roller pair 4 is also provided.

  Further, the printer 200 includes a contact heating type fixing device 100 as a fixing unit for fixing the toner image on the paper P onto which the toner image has been transferred, and the fixed paper P is discharged to the outside of the printer 200 main body. A discharge roller 7 is provided. In addition, a discharge tray 17 for stacking sheets P discharged to the outside of the main body of the printer 200 by the discharge roller 7 is provided at the upper part of the main body of the printer 200. Further, in the apparatus main body below the paper discharge tray 17, toner bottles 9Y, C, M, and Bk filled with toners of yellow, cyan, magenta, and black are provided.

In addition to the transfer belt 11 and the primary transfer rollers 12Y, C, M, and Bk, the transfer belt unit 10 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 tension urging means for the transfer belt 11, and the driven roller 73 is provided with urging means using a spring or the like. Such a transfer belt unit 10, the primary transfer rollers 12Y, C, M, and Bk, the secondary transfer roller 5, and the belt cleaning device 13 constitute a transfer device 71.
The paper feeding device 61 is disposed at the lower part of the main body of the printer 200 and has a feeding roller 3 that comes into contact with the upper surface of the uppermost paper P. The uppermost sheet P is fed toward the registration roller pair 4 by rotating the feeding roller 3 counterclockwise in the drawing.

The belt cleaning device 13 provided in the transfer device 71 includes a cleaning brush and a cleaning blade disposed so as to face and contact the transfer belt 11. The belt cleaning device 13 cleans the transfer belt 11 by scraping and removing foreign matters such as residual toner on the transfer belt 11 with a cleaning brush and a cleaning blade.
Further, the belt cleaning device 13 has a discharging means for carrying out and discarding the residual toner removed from the transfer belt 11.

Hereinafter, the fixing device 100 which is a characteristic part of the printer 200 of the present embodiment will be described with reference to the drawings.
FIG. 2 is a schematic explanatory diagram of the fixing device 100.
As shown in FIG. 2, the fixing device 100 includes a fixing belt 101 as an endless fixing member that can rotate, and a pressure roller 103 as a pressing member that is disposed to face the fixing belt 101 and can rotate. Yes. Further, the fixing belt 101 is moved from the inner peripheral side by the two halogen heaters 102, ie, the first halogen heater 102A and the second halogen heater 102B, which are a plurality of fixing heat sources as heating means for heating the fixing belt 101 at the non-nip portion. It is configured to be directly heated by radiant heat.
Further, in the fixing belt 101 of the fixing device 100 shown in FIG. 2, there is a nip forming member 106 that forms a nip portion with the pressure roller 103 via the fixing belt 101. It slides through the movement assisting member 116. The toner image on the paper P is fixed at the nip portion N by heating and pressing.

Here, in the example shown in FIG. 2, the shape of the portion of the heat transfer assisting member 116 facing the fixing belt 101 is flat, but may be a concave shape or other shapes. In the case of the concave nip portion, the discharge direction of the leading end of the recording material is closer to the pressure roller, and the separation is improved, so that the occurrence of jam is suppressed.
Inside the fixing belt 101, a nip forming member 106 disposed to face the pressure roller 103, and an end portion that is integrally provided at both ends of the nip forming member 106 and heats the fixing belt 101 at the nip portion. It has two end heaters 126 as heat sources. Further, the heat transfer assisting member 116 covering the nip forming member 106 and the surface of the end heater 126 facing the inner surface of the fixing belt 101, and the nip forming member 106 are held against the pressure applied from the pressure roller 103. A stay 107 is also provided.
Further, as will be described in detail later, the left end heater 126a and the right end heater 126b, which are the two end heaters 126 provided at the respective ends in the longitudinal direction, are provided independently and have a continuous shape. Absent.

The nip forming member 106, the heat transfer assisting member 116, and the stay 107 all have a length that extends in the width direction of the fixing belt 101 (hereinafter referred to as “longitudinal direction”).
The heat transfer auxiliary member 116 is provided to prevent the heat of each end heater 126 from staying locally, and to actively move the heat in the longitudinal direction to reduce the temperature non-uniformity in the longitudinal direction. Yes.
For this reason, the heat transfer auxiliary member 116 is preferably a material that can transfer heat in a short time, and is preferably a member such as copper, aluminum, or silver having high thermal conductivity. In consideration of cost, availability, thermal conductivity characteristics, and workability, it is most desirable to use copper.
In this example, the surface of the heat transfer assisting member 116 that faces the inner surface of the fixing belt 101 is a surface that directly contacts the fixing belt 101 and serves as a nip forming surface.

The fixing belt 101 is composed of a metal belt such as nickel or SUS, an endless belt using a resin material such as polyimide, or a film.
The surface layer of the fixing belt 101 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 base material of the fixing belt 101 and the PFA or PTFE layer. When there is no silicone rubber layer, the heat capacity is reduced and the fixability is improved. However, when the unfixed image is crushed and fixed, the minute irregularities on the surface of the fixing belt 101 are transferred to the image and become solid on the image. There may be a problem that a yuzu skin-like gloss unevenness (yuzu 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, minute unevenness is absorbed and the skin image is improved.

The stay 107 has a shape having an upright portion standing upright on the side opposite to the nip portion N side, and a first halogen heater 102A and a second halogen heater 102B as a fixing heat source are arranged with the upright portion separated.
The fixing belt 101 is directly heated by radiant heat from the inner surface side by these two halogen heaters 102.
Further, by disposing each halogen heater 102 on the inner peripheral side of the fixing belt 101, the fixing device 100 including the rotatable endless fixing belt 101 can be easily configured in a compact manner.

The above-described stay 107 as a support member for supporting the nip forming member 106 and the nip portion N is provided inside the fixing belt 101 to prevent the nip forming member 106 that receives pressure from the pressure roller 103 from bending. A uniform nip width can be obtained in the axial direction.
The stay 107 is held and fixed by a flange as a holding member at both ends. Further, a reflection member 109 is provided between the two halogen heaters 102 and the stay 107, and wasteful energy consumption due to the stay 107 being heated by radiant heat from each halogen heater 102 is suppressed.
Here, instead of providing the reflecting member 109, the same effect can be obtained even if the surface of the stay 107 is heat-insulated or mirror-finished.

The pressure roller 103 has an elastic rubber layer 104 on the outer periphery of the cored bar 105, and a release layer (PFA or PTFE layer) on the surface in order to obtain releasability.
The pressure roller 103 is rotated by a driving force transmitted from a driving source such as a motor provided in the main body of the printer 200 via a gear. The pressure roller 103 is pressed against the fixing belt 101 by a spring or the like, and has a predetermined nip width when the elastic rubber layer 104 is crushed and deformed.

The pressure roller 103 may be a hollow roller, and the pressure roller 103 may have a heating source such as a halogen heater.
The elastic rubber layer 104 may be solid rubber, but if there is no heater inside the pressure roller 103, sponge rubber may be used. Sponge rubber is more preferable because heat insulation is increased and heat of the fixing belt 101 is less likely to be taken away.

The fixing belt 101 is rotated by the pressure roller 103.
In the example shown in FIG. 2, the pressure roller 103 is rotated by a driving source, and the driving force is transmitted to the belt at the nip portion N, whereby the fixing belt 101 is rotated.
The fixing belt 101 is sandwiched and rotated at the nip portion N, and travels while being guided by the flanges at both ends other than the nip portion N.
With the above-described configuration, it is possible to realize a fixing device 100 that is inexpensive and has a fast warm-up.

Here, a conventional fixing device 100 will be described with reference to FIG.
FIG. 3 is an explanatory diagram of a conventional example of a fixing device having two halogen heaters.
As such a fixing device 100, for example, a fixing device described in Patent Document 2 is known.

A conventional fixing device 100 shown in FIG. 3 is arranged on a rotatable endless fixing belt 101, two halogen heaters 102 for heating the fixing belt 101 from the inside, and an inner peripheral side of the fixing belt 101. This is a so-called belt-type fixing device having a nip forming member 106 and a pressure roller 103 that presses a sheet nipped and conveyed by the fixing belt 101 toward the fixing belt 101.
Further, in the fixing device 100, the length and arrangement position of the heat generating portions in the longitudinal direction (direction orthogonal to the endless movement direction of the fixing belt 101) of the two halogen heaters 102 for heating the inner peripheral surface of the fixing belt 101 are different. It is

  However, in this conventional example, since the two halogen heaters 102 are surrounded by the reflecting member 109, the heating efficiency is lowered by the attenuation of radiation due to reflection and the narrowing of the irradiation angle as shown by the bidirectional arrows. To do. Here, the irradiation angle is an angle at which the radiation from each halogen heater 102 directly hits the fixing belt 101. For example, one halogen heater 102 is a central heater that heats the longitudinal center of the fixing belt 101, and the other halogen heater 102 is an end heater that heats the longitudinal end of the fixing belt 101.

On the other hand, there is a market need for image formation on a normal standard recording material, for example, a paper having a paper width wider than the A3 longitudinal paper width (297 mm) (so-called nobi paper).
However, for example, in the case where fixability at a paper width up to nobi paper is required, it is necessary to extend the heat generation width of the end heater that heats the end in the longitudinal direction to the end of the nobi paper, and a standard size such as A3 size Overheating of the end of the fixing belt 101 occurs for the recording material. In order to prevent this, it is necessary to adjust the productivity, etc., or to provide a structure that prevents excessive temperature rise in the non-sheet passing portion such as providing a rotatable shielding member (reference numeral 27 in Patent Document 1). There was a problem of incurring cost increase.

Therefore, in the present embodiment, the fixing device 100 is configured as follows.
As shown in FIG. 2, the stay 107 includes a first member 107A and a second member 107B each having a substantially L-shaped cross section.
The first member 107 </ b> A and the second member 107 </ b> B partition the two halogen heaters 102 and are fixed to the nip forming member 106. Further, as shown in FIG. 4, the first member 107A and the second member 107B extend linearly in the longitudinal direction of the heater, and the cross section of the stay 107 is formed in a substantially T-shape.
Since the two halogen heaters 102 are arranged in separate upper and lower regions sandwiching the stay 107, the glass tubes can be heated when the heaters are lit as in the conventional configuration shown in FIG. As a result, heating efficiency does not decrease.

  Further, a reflection member 109 is provided between each halogen heater 102 and the stay 107, and wasteful energy consumption due to the stay 107 being heated by radiant heat from each halogen heater 102 can be suppressed. Here, instead of providing the reflecting member 109, the same effect can be obtained even if the surface of the stay 107 is heat-insulated or mirror-finished.

As shown in FIG. 5, the surface of the nip forming member 106 on the side opposite to the fixing belt 101 comes into contact with the side surface of the stay 107 on the pressure roller 103 side to be integrated. When configured in this way, shapes such as bosses and pins may be provided and combined.
The heat transfer assisting member 116 is fitted and integrated so as to cover the surface of the rectangular parallelepiped nip forming member 106 that faces the inner surface of the fixing belt 101. Here, the integral configuration of the heat transfer assisting member 116 and the nip forming member 106 may be provided by engaging with a claw or the like, but means such as adhesion may be used.

As shown in FIG. 5, left and right concave portions 106a and 106b as stepped portions are formed at both ends in the longitudinal direction of the nip forming member 106, and left end heater 126a and right end heater are respectively formed in these portions. 126b is accommodated and fixed.
Further, the opposed surface 116c of the heat transfer assisting member 116 facing the pressure roller 103 becomes a nip forming surface, but the nip forming surface is substantially the nip forming surface in terms of mechanical strength. This is a facing reference surface 106c facing the surface.

Here, the heat distribution and arrangement of the two halogen heaters 102 which are heat sources for directly heating the fixing belt 101 of the present embodiment and the two end heaters 126 integrally provided at both ends of the nip forming member 106. The end heat source control method and the like will be described with reference to the drawings.
FIG. 6 is an explanatory diagram of the positional relationship in the longitudinal direction between the heaters provided in the fixing device 100 and the paper to be fixed. FIG. 7 is an explanatory diagram of the positional relationship in the longitudinal direction of each heater near both ends provided in the fixing device 100, and FIG. 7A is an explanatory diagram of the positional relationship and heat distribution of the second halogen heater 102B. FIG. 7B is an explanatory diagram of the positional relationship and heat distribution of the right end heater 126b. FIG. 8 is an explanatory diagram of the positional relationship between each heater near the both ends provided in the fixing device 100 and the temperature degree detecting means, and FIG. 8A is an explanatory diagram of the positional relationship and heat distribution of the second halogen heater 102B. FIG. 8B is an explanatory diagram of the positional relationship and heat distribution of the right end heater 126b, and FIG. 8C is an explanatory diagram of the positional relationship of the right temperature detection means 136b.

As shown in FIG. 6, the first halogen heater 102 </ b> A is a halogen heater corresponding to a small size paper P such as A4 vertical in which the light distribution distribution of the central portion 102 c in the longitudinal direction of the fixing belt 101 is dense.
The second halogen heater 102B is a halogen heater corresponding to a sheet P of A3 size or the like in which the light distribution at both ends 102d in the longitudinal direction is dense.
In the halogen heaters 102, when the paper P is a small size, only the first halogen heater 102A is turned on, the non-sheet passing portion at the end in the longitudinal direction is heated unnecessarily, or the end of the end due to continuous sheet passing is determined. Overheating is prevented.
The left end heater 126a and the right end heater 126b are arranged so that a part of the heating range in the longitudinal direction overlaps the end of the second halogen heater 102B in the same direction. In other words, the left end heater 126a and the right end heater 126b are arranged so as to compensate for a decrease in heat distribution output at a position corresponding to the extreme end of the sheet width of the second halogen heater 102B.

  Further, as described above, the fixing device 100 includes the fixing heat sources of the first halogen heater 102A and the second halogen heater 102B having different heat distributions in the longitudinal direction as heating means for the fixing belt 101. . Thereby, the heating of the range of the fixing belt 101 corresponding to the paper size of the paper P passing through the inside of the region heated by each end heater 126 can be efficiently performed.

Here, the heat distribution of the second halogen heater 102B and each end heater 126 will be described with reference to FIG.
Normally, the second halogen heater 102B does not output 100% of heat distribution to the target heat distribution amount up to the end of the filament, and the heat distribution output of the end is 50% due to the heat amount sagging. It is common to define up to this point as a heat generating part. Also, each end heater 126 does not output 100% of the target heat distribution amount up to the heater end, and the heat distribution output sags at the end in the longitudinal direction of the heat generation pattern.
For this reason, when a drop in the heat distribution output occurs at the longitudinal boundary between the second halogen heater 102B and each end heater 126, a fixing defect occurs particularly at the end of the recording material having a width wider than a standard size such as nobi paper. there's a possibility that. For this reason, it is desirable that the end portions where the heat distribution outputs of the second halogen heater 102B and the end heaters 126 become 100% be the boundary positions in the longitudinal direction.

Further, as described above, as the material of the heat transfer auxiliary member 116, a material having high thermal conductivity such as copper or aluminum is used.
By using a material having such a high thermal conductivity, the heat of each halogen heater 102 and each end heater 126 is prevented from staying locally, and the heat is positively moved in the longitudinal direction. Reduces temperature non-uniformity.

However, the heat transfer assisting member 116 and the inner surface of the fixing belt 101 slide, and if the metal material is rubbed against the inner surface of the fixing belt 101 as it is, there is a problem that the coefficient of friction increases and the unit torque increases. For this reason, it is desirable that the facing surface 116c (see FIG. 5) of the heat transfer assisting member 116 facing the fixing belt 101 is smooth, and in order to further improve the slidability, application is performed to reduce the friction coefficient. desirable.
Specifically, it is possible to maintain good sliding between the heat transfer assisting member 116 and the inner surface of the fixing belt 101 by applying a fluorine-based paint or coating such as PFA or PTFE.
Further, as described above, the heat transfer auxiliary member 116 slides on the inner surface of the fixing belt 101, and a lubricant such as fluorine grease or silicone oil is applied between the heat transfer auxiliary member 116 and the inner surface of the fixing belt 101. Thus, the sliding torque can be reduced.

Next, temperature detection means for controlling the temperature of each end heater 126 will be described with reference to FIG.
The temperature detection means of the fixing belt 101 is advantageous in that the contact type is inexpensive and has high accuracy, but a minute sliding trace is generated at the contact position, and there is an abnormality such as a minute gloss unevenness in the image at the corresponding position. May occur. For this reason, a configuration in which a contact sensor is not used particularly in the standard size range of a color image output machine has become mainstream.
However, in the configuration of the present embodiment, the left end heater 126a and the right end heater 126b are heating members for heating the outside of the second halogen heater 102B that heats the paper end portion of the standard maximum size (so-called nobi portion). It is.

The nobi part is used for ears when you want to create images up to the edge of the standard maximum size paper edge, line images called registration marks used for printing alignment, and small area solid patches for color confirmation. It is a part that is used as a part to be used. For this reason, since the nobby portion is often a portion that is cut as the final medium, minute gloss unevenness or the like generated on the contact trace of the contact-type temperature detection means does not appear as an abnormal image.
Thereby, the left temperature detecting means 136a and the right temperature detecting means 136b for detecting the temperatures of the left end heater 126a and the right end heater 126b are less likely to remain as final images, outside the fixed maximum size in the longitudinal direction, and By providing it inside the maximum width of the Nobi paper (width indicated by W in FIG. 8 (c)), it becomes possible to detect the temperature with high accuracy and to use an inexpensive and highly accurate contact thermistor. Become.
Here, the position of the right temperature detecting means 136b provided in the width indicated by W in FIG. 8C is a position corresponding to the right end heater 126b.

  Next, the configuration of the heat transfer assisting member 116, which is the largest feature of the fixing device 100 of the present embodiment, will be described with reference to a plurality of examples.

Example 1
First, Example 1 of the heat transfer auxiliary member 116 included in the fixing device 100 of the present embodiment will be described with reference to the drawings.
FIG. 9 is an explanatory side view of the heat transfer assisting member 116 of this embodiment, and FIG. 10 is a contact portion between the heat transfer assisting member 116 of this embodiment and the left end heater 126a and the right end heater 126b that are end heat sources. FIG.
As described above, the heat transfer assisting member 116 uses a material having high thermal conductivity such as copper or aluminum, and prevents the heat of each halogen heater 102 and each end heater 126 from staying locally. Heat is moved in the longitudinal direction to reduce temperature non-uniformity in the longitudinal direction.

Longitudinal temperature non-uniformity is more likely to occur as the image forming speed (printing speed) is faster, and there is a method of using a member having high thermal conductivity such as copper or aluminum as the heat transfer auxiliary member 116 in order to cope with high speed. .
As another method, by increasing the cross-sectional area (plate thickness) in the heat transfer direction, the amount of heat transfer can be increased and the temperature can be made uniform quickly.
However, increasing the plate thickness in this way improves the temperature non-uniformity, but at the same time, the rigidity of the heat transfer assisting member 116 also increases.

In the fixing device 100 of this embodiment, as shown in FIG. 5, the left end heater 126 a and the right end heater 126 b are accommodated in the nip forming member 106, and the heat transfer assisting member 116 covers the rectangular parallelepiped nip forming member 106. It is fitted and integrated.
For this reason, when the rigidity of the heat transfer assisting member 116 is too high, the adhesion with the left end heater 126a and the right end heater 126b, which are the end heat sources, decreases due to the force resisting the pressing force from the pressure roller 103. End up.

The heat transfer auxiliary member 116 is obtained by bending a copper or aluminum material plate into a shape as shown in FIG.
As shown in FIG. 9, the surfaces of the left contact portion 116a and the right contact portion 116b that are in contact with the left end heater 126a and the right end heater 126b are required to have high processing flatness. A slight deformation is unavoidable due to variations in component accuracy.
Each end heater 126 transmits heat to the fixing belt 101 via the heat transfer assisting member 116. If the contact state with each end heater 126 is poor, the heat is efficiently transferred to the fixing belt 101 and the paper. An abnormal image may be generated due to insufficient heat amount without being transferred to the toner on P. In addition, since heat transfer efficiency is deteriorated, a problem such as an increase in power consumption also occurs.

Therefore, in the heat transfer assisting member 116 of this embodiment, as shown in FIG. 9, the pressing force from the elastic rubber layer 104 of the pressure roller 103 is A, the flatness of the heat transfer assisting member 116, and the force for correcting the deformation. When (deformation correcting force) is B, the adhesiveness is improved by setting A> B.
In addition, the elastic rubber layer 104 is generally formed of silicone rubber or the like, and the pressing force A due to a decrease in rubber hardness over time may decrease, so the above relationship is maintained by taking into account the pressing force over time. To do.
Here, the shaft of the metal core 105 of the pressure roller 103 shown in FIG. 9 is rotatably supported by a bearing 105a.

  Further, for example, as shown in FIG. 10, when the heat transfer assisting member 116 is twisted, the heat transfer assisting member 116 that has been twisted contacts the contact point 106 d of the nip forming member 106, and the adhesion is reduced. However, the torsional rigidity can be corrected under the pressing force of the pressure roller 103. Here, although the example shown in FIG. 10 is a case where twisting occurs, a configuration that can ensure adhesion by adopting the same configuration even if the heat transfer assisting member 116 is deformed in the longitudinal direction and the lateral direction. It can be.

  As described above, the fixing device 100 having the heat transfer assisting member 116 of the present embodiment of the present embodiment is a fixing heat source serving as a fixing belt 101 and a heating unit that heats the fixing belt 101 at the non-nip portion. A halogen heater 102A and a second halogen heater 102B are provided. Further, a nip forming member 106 disposed on the inner peripheral side of the fixing belt 101, a pressure roller 103 that presses (presses) the paper P sandwiched and conveyed by the fixing belt 101 toward the fixing belt 101, and fixing. A left end heater 126a and a right end heater 126b for heating the vicinity of both end portions of the belt 101 at the nip portion are also provided.

In addition, a heat transfer assisting member 116 that assists heat transfer in the longitudinal direction of the fixing belt 101 at the nip portion N formed between the fixing belt 101 and the pressure roller 103 is provided on the fixing belt 101 side of the nip forming member 106. Provided. Accordingly, a left end heater 126a and a right end heater 126b are provided at both ends in the longitudinal direction between the nip forming member 106 and the heat transfer assisting member 116. The contact portions such as the left contact portion 116a and the right contact portion 116b with the left end heater 126a and the right end heater 126b of the heat transfer assisting member 116 have a stress smaller than the pressing (pressing) force by the pressure roller 103. It was configured to be deformable. That is, assuming that the pressing force of the pressure roller 103 from the elastic rubber layer 104 is A, the flatness of the heat transfer assisting member 116, and the force for correcting deformation (deformation correcting force) is B, A> B. Configured.
Here, in the following description, only the effect that can be achieved by the fixing device 100 and the reason that the effect can be achieved will be described, and an example of a specific configuration of the heat transfer assisting member 116 will be described later. Examples 2 to 4 will be described with specific examples.

As described above, by configuring the fixing device 100 including the heat transfer assisting member 116, the following effects can be achieved.
Each contact portion 116 with each end heater 126 of the heat transfer auxiliary member 116 can be deformed with a stress smaller than the pressing force A from the elastic rubber layer 104 of the pressure roller 103. For this reason, the fixing belt 101 and the heat transfer assisting member 116, and the heat transfer assisting member 116 and each end heater 126 can be brought into close contact with each other by using a pressing force for forming the nip portion N. Therefore, unlike the conventional configuration, the fixing belt 101 and the heat transfer assisting member 116, and the heat transfer assisting member 116 and each end heater 126 are in close contact with each other, and good running performance of the fixing belt 101 is obtained. By improving the heat conductivity, good heating efficiency by each end heater 126 can be maintained.
Therefore, it is possible to provide the fixing device 100 that can obtain good heating efficiency while maintaining a stable running of the fixing belt 101.

Here, the configuration in which each end heater 126 is simply provided between the nip forming member 106 and the heat transfer assisting member 116 may cause the following problems (problems).
The parts surface shape (flatness) and attachment position (attachment accuracy) of each of the nip forming member 106, each end heater 126, and the heat transfer assisting member 116 may vary from part to part. As described above, when the variation occurs, the contact property between the heat transfer assisting member 116 and each end heater 126 also varies, and the heat of each end heater 126 is not efficiently transmitted to the fixing belt 101, resulting in insufficient heat. This is a problem that an abnormal image is generated.
Further, if it is attempted to increase the component accuracy and the mounting accuracy of the nip forming member 106, each end heater 126, and the heat transfer assisting member 116, the cost of the fixing device 100 is increased.
In addition, it is possible to improve the contact property by applying heat conductive grease to assist the heat transfer to the contact surface, but if it is applied directly to each end heater 126, the grease is likely to flow out and deteriorate with time. Since the heat transfer state changes with time, it is not preferable to use it near each end heater 126 in terms of product design.

On the other hand, each contact portion 116 of each heat transfer assisting member 116 with each end heater 126 can be deformed with a stress smaller than the pressing force A from the elastic rubber layer 104 of the pressure roller 103. For the reason explained in the above, it is possible to suppress the occurrence of the above-mentioned problems.
Each contact portion 116 with each end heater 126 of the heat transfer auxiliary member 116 can be deformed with a stress smaller than the pressing force A from the elastic rubber layer 104 of the pressure roller 103. Therefore, the heat transfer assisting member 116 can be deformed so as to be in close contact with each end heater 126 regardless of the component accuracy and mounting accuracy of the nip forming member 106, each end heater 126, and the heat transfer assisting member 116. it can. The heat transfer assisting member 116 and each end heater 126 are brought into close contact with each other by being deformed in this manner, so that heat transfer between the heat transfer assisting member 116 and each end heater 126 can be improved.
Therefore, heat transfer between the heat transfer assisting member 116 and each end heater 126 can be improved regardless of the component accuracy and mounting accuracy of the nip forming member 106, each end heater 126, and the heat transfer assisting member 116. A fixing device 100 can also be provided.

(Example 2)
Next, Example 2 of the heat transfer assisting member 116 included in the fixing device 100 of the present embodiment will be described with reference to the drawings.
FIG. 11 is an explanatory side view of the heat transfer assisting member 116 of this embodiment, and illustrates a contact portion with the left end heater 126a.
In the heat transfer assisting member 116 of the present embodiment and the heat transfer assisting member of the first embodiment, the heat transfer assisting member 116 of the present embodiment is cut into the heat transfer assisting member 116 and the following end heater inner end notch. The only difference is that 126d is provided and a portion having a low second-order moment is provided.
This is an end heater inner end notch 126d provided at least at one position on the center side in the longitudinal direction of the heat transfer assisting member 116 from the position where each end heater 126 abuts.
Therefore, the configuration and effects similar to those of the heat transfer auxiliary member of the first embodiment will be omitted as appropriate, and similar members will be denoted by the same reference symbols unless otherwise distinguished. I will explain.

As described above, the heat transfer assisting member 116 has a function of uniformly moving the portion where the temperature is excessively increased due to the difference between the heat source length and the sheet size during the sheet passing in the axial direction. Among them, it is preferable in terms of thermal efficiency that the heat insulation and the contact state with the nip forming member 106 are poor.
Therefore, the heat transfer assisting member 116 in the sheet passing range may have a high rigidity and ensure the nip width and nip surface pressure by the pressing force from the pressure roller 103.
On the other hand, the heat transfer assisting member 116, the left end heater 126a, and the right end heater are provided with a portion that reduces the secondary moment of section in a part of the sheet conveyance center side in a range in contact with the left end heater 126a and the right end heater 126b. Improve the contactability of 126b.
As a specific example, as shown in FIG. 11, the contact between the heat transfer assisting member 116, the left end heater 126a, and the right end heater 126b is improved by providing an end heater inner end cutout 116d. With this configuration, the temperature uniformity in the longitudinal direction of the shaft can be made substantially unchanged over the entire area.

  As described above, the fixing device 100 having the heat transfer assisting member 116 according to the present exemplary embodiment has at least one position on the center side in the longitudinal direction of the heat transfer assisting member 116 with respect to the position where each end heater 126 abuts. In addition, a portion having a low cross-sectional secondary moment, such as providing an end heater inner end notch 126d, is provided.

As described above, by configuring the fixing device 100 including the heat transfer assisting member 116, the following effects can be obtained.
Normally, when the heat transfer assisting member 116 is deformed so as to be twisted with respect to the pressing member, the heat transfer assisting member 116 and each end heater 126 are likely to be in point contact where the contact points 106d and the like are formed, The heat transfer between each end heater 126 and each end heater 126 may be deteriorated.
On the other hand, the heat transfer assisting member 116 is twisted with respect to the pressure roller 103 by providing a portion that is more easily deformed on the center side in the longitudinal direction than the position where each end heater 126 of the heat transfer assisting member 116 abuts. Even when it is deformed, the position of the heat transfer assisting member 116 pressed by the pressure roller 103 in contact with each end heater 126 is easily deformed.
Therefore, the heat transfer assisting member 116 and each end heater 126 are easily brought into close contact with each end heater 126 at a position where the end heater 126 abuts, and the heat transfer between the heat transfer assisting member 116 and each end heater 126 is likely to be deteriorated. it can.

(Example 3)
Next, Example 3 of the heat transfer auxiliary member 116 included in the fixing device 100 of the present embodiment will be described with reference to the drawings.
FIG. 12 is an explanatory side view of the heat transfer assisting member 116 of this embodiment, and illustrates a contact portion with the left end heater 126a. FIG. 13 is an explanatory diagram of the distribution in the longitudinal direction of the pressing force (pressing force) by the pressure roller 103.
In the heat transfer assisting member 116 of this embodiment and the heat transfer assisting member of Embodiment 2, the heat transfer assisting member 116 of this embodiment is added to the heat transfer assisting member 116 in addition to the end heater inner end notch 126d, The only difference is that a plurality of end heater cutouts 126e as described below are provided.
A plurality of end heater part notches 126e are provided in a contact range of the heat transfer assisting member 116 with each end heater 126.
Therefore, the configuration and effects similar to those of the heat transfer assisting members in Examples 1 and 2 will be omitted as appropriate, and similar members will be denoted by the same reference symbols unless otherwise distinguished. A description will be given.

As shown in FIG. 12, the heat transfer assisting member 116 of the present embodiment has an end heater inner notch 116d and an end heater notch 116e in contact with the left end heater 126a and the right end heater 126b. It has expanded to.
As described above, the plurality of end heater section notches 116e are provided in the contact range with the left end heater 126a and the right end heater 126b, and the flexibility and flexibility of the left end heater 126a and the right end heater 126b are increased. It is easy to follow the flatness of the movement assisting member 116 to improve the adhesion.

Here, as shown in FIG. 13, the distribution of the pressing force A of the pressure roller 103 is such that both ends have a large degree of freedom of deformation of the elastic rubber layer 104, so that the pressing force decreases toward the end. The same phenomenon also occurs in a pressure roller (a pressure roller having a configuration including a grip roller) that does not have a surface layer at both ends of the pressure roller 103.
Therefore, the end heater portion notch 116e may be configured such that the interval between the end heater portions notches 116e is made narrower toward the end portion to give flexibility.

  As described above, the fixing device 100 having the heat transfer assisting member 116 according to the present embodiment is provided with the end heater portion notch 126 e in the contact range of the heat transfer assisting member 116 with each end heater 126. A plurality of portions having a low cross-sectional second moment are provided.

As described above, by configuring the fixing device 100 including the heat transfer assisting member 116, the following effects can be obtained.
Normally, if the flatness of the contact range between the heat transfer assisting member 116 and each end heater 126 is poor, it is difficult for the heat transfer assisting member 116 and each end heater 126 to be in close contact with each other. Heat transfer of the heater 126 is deteriorated.
On the other hand, the flatness of the contact range between the heat transfer assisting member 116 and each end heater 126 is poorly adhered by providing a portion that is easily deformed in the contact range of each heat transfer assisting member 116 with each end heater 126. Even when it is difficult, the flatness can be corrected by following the shape of each end heater 126 to improve the adhesion.
Therefore, the heat transfer assisting member 116 and each end heater 126 are easily brought into close contact with each other at the end heater 126 contact position, and the possibility that heat transfer between the heat transfer assisting member 116 and each end heater 126 is deteriorated can be eliminated. .
Further, the heat transfer assisting member 116 is provided with a plurality of portions having a low second-order moment such as the end heater notch 126e in the contact range of each end heater 126 with the heat transfer assisting member 116. Improvement of heat transfer efficiency due to the heat capacity reduction effect of 116 can also be expected.

Example 4
Next, Example 4 of the heat transfer auxiliary member 116 included in the fixing device 100 of the present embodiment will be described with reference to the drawings.
FIG. 14 is an explanatory side view of the heat transfer auxiliary member 116 of this embodiment, and illustrates a contact portion with the left end heater 126a.
In the heat transfer assisting member 116 of the present embodiment and the heat transfer assisting members of Embodiments 2 and 3, the heat transfer assisting member 116 of the present embodiment is the left which is a contact surface with the left end heater 126a and the right end heater 126b. The only difference is that the plate thickness of the contact portion 116a and the right contact portion 116b is made thinner than the other portions.
Therefore, the configuration and effects similar to those of the heat transfer assisting members of Examples 1 to 3 will be appropriately omitted and described, and the same reference numerals will be given to similar members unless there is a particular need for distinction. A description will be given.

As shown in FIG. 14, the heat transfer assisting member 116 of this embodiment is configured so that the thickness t1 of the left contact portion 116a and the right contact portion 116b, which are contact surfaces with the left end heater 126a and the right end heater 126b, is the other portion. It is made thinner than the plate thickness t2.
Specifically, the contact range of the heat transfer assisting member 116 with the left end heater 126a and the right end heater 126b is made thinner than the counter pressure t2 of other portions by press molding, cutting, or the like. As described above, since the deformation correction force B is reduced as the plate thickness t1 is reduced, the above-described object can be achieved even with a small device that can obtain only the pressing force of the pressure roller 103 with a low load. That is, by making the vicinity of each end heater 126 of the heat transfer auxiliary member 116 thin, it has deformation flexibility, and it becomes easy to correct even in a poor flatness state such as twisting and undulation. Good contactability.
Furthermore, the heat transfer assisting member 116 is thinned, so that the heat capacity of the thinned portion can be reduced, the heating speed by the left end heater 126a and the right end heater 126b is increased, and the warm-up time can be shortened. .

  As described above, in the fixing device 100 having the heat transfer assisting member 116 according to the present exemplary embodiment, the plate thickness t1 of the left contact portion 116a and the right contact portion 116b is transferred by heat transfer in the region in contact with each end heater 126. The auxiliary member 116 is thinner than the plate thickness t2 on the center side in the longitudinal direction.

As described above, by configuring the fixing device 100 including the heat transfer assisting member 116, the following effects can be obtained.
By making the vicinity of each end heater 126 of the heat transfer assisting member 116 thin, it has deformation flexibility, and it becomes easy to correct even in a poor flatness state such as torsion and undulation, and contact with each end heater 126 is possible. Becomes better. Furthermore, since the heat transfer assisting member 116 has a low heat capacity due to the thinning, it can be rapidly heated by the respective end heaters 126, and the warm-up time can be shortened even when passing a Nobi paper such as A3 Nobi paper.

As described above, the present embodiment has been described with reference to the drawings. However, the specific configuration is not limited to the configuration provided with the above-described fixing device 100 of the present embodiment, and various configurations can be made without departing from the gist. You may make changes.
For example, the fixing device 100 of the present embodiment is not limited to the one provided with a heating unit that heats the non-nip portion N on the inner peripheral side of the fixing belt 101 shown in FIG. It is also applicable to a fixing device provided with the above heating means on the outer peripheral side of the fixing belt.
Further, the image forming apparatus provided with the fixing device 100 of the present embodiment is not limited to the color printer shown in FIG. 1, but may be a monochrome image forming apparatus, other printers, copiers, facsimiles, or a complex machine thereof. It can be installed.
These image forming apparatuses can achieve the same effects as those of the fixing apparatus 100 described in the present embodiment. Further, by providing the fixing device 100 of this embodiment in these, an image forming apparatus excellent in energy saving can be provided.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect A)
A rotatable endless fixing member such as the fixing belt 101, and heating means such as a first halogen heater 102A and a second halogen heater 102B, which are fixing heat sources, as heating means for heating the fixing member at a non-nip portion; A nip forming member such as the nip forming member 106 disposed on the inner peripheral side of the fixing member and a recording material such as paper P sandwiched and conveyed by the fixing member are pressed by pressing the recording material toward the fixing member. In a fixing device such as a fixing device 100 including a pressing member such as a pressure roller 103 and an end heat source such as a left end heater 126a and a right end heater 126b that heat the vicinity of both ends of the fixing member at a nip portion. A heat transfer assisting member for assisting heat transfer in the longitudinal direction of the fixing member at a nip portion such as a nip portion N formed between the fixing member and the pressing member. A heat transfer auxiliary member such as 16 is provided on the fixing member side of the nip forming member, and the end heat sources are provided at both ends in the longitudinal direction between the nip forming member and the heat transfer auxiliary member. The contact portions such as the left contact portion 116a and the right contact portion 116b with the end heat source of the member are configured to be deformable with a stress smaller than the pressing force by the pressing member.

According to this, as described in the present embodiment, the following effects can be achieved.
Since the contact portion of the heat transfer assisting member with the end heat source can be deformed with a stress smaller than the pressing force by the pressing member, the fixing member and the heat transfer assisting member using the pressing force for forming the nip portion, and The heat transfer auxiliary member and the end heat source can be brought into close contact with each other. For this reason, unlike the conventional configuration, the fixing member and the heat transfer assisting member, and the heat transfer assisting member and the end heat source are in close contact with each other, the fixing member can have good running performance and the heat transfer performance can be improved. Good heating efficiency by the partial heat source can be maintained.
Therefore, it is possible to provide a fixing device that can obtain good heating efficiency while maintaining stable running of the fixing member.

Here, in the configuration in which the end heat source is simply provided between the nip forming member and the heat transfer assisting member, the following problems (problems) may occur.
The part surface shape (flatness) and attachment position (attachment accuracy) of each of the nip forming member, the end heat source, and the heat transfer assisting member may vary from part to part. As described above, when the variation occurs, the contact property between the heat transfer auxiliary member and the end heat source also varies, and the heat of the end heat source is not efficiently transmitted to the fixing member, and an abnormal image due to insufficient heat amount is generated. It is a malfunction that ends.
And if it is going to raise the component precision and attachment precision of a nip forming member, an edge part heat source, and a heat transfer auxiliary member, the cost of a fixing device will be raised.
In addition, it is possible to improve the contact by applying heat conduction grease to the contact surface to assist heat transfer. However, if it is applied directly to the heat source, it is easy for grease to flow out and deteriorate over time at high temperatures. Since it changes with time, it is not preferable to use it near a heat source in product design.

On the other hand, the contact portion of the heat transfer assisting member with the end heat source can be deformed with a stress smaller than the pressing force of the pressing member, thereby suppressing the occurrence of the above problem for the reason described below. .
Since the contact portion of the heat transfer auxiliary member with the end heat source can be deformed with a stress smaller than the pressing force of the pressing member, regardless of the component accuracy and mounting accuracy of the nip forming member, end heat source, and heat transfer auxiliary member The heat transfer auxiliary member can be deformed so as to be in close contact with the end heat source. The heat transfer between the heat transfer auxiliary member and the end heat source can be improved by deforming the heat transfer auxiliary member and the end heat source in close contact with each other.
Therefore, it is possible to provide a fixing device that can improve heat transfer between the heat transfer auxiliary member and the end heat source regardless of the component accuracy and the mounting accuracy of the nip forming member, the end heat source, and the heat transfer auxiliary member.

(Aspect B)
In (Aspect A), the heating means is arranged on an inner peripheral side of the fixing member.
According to this, as described in the present embodiment, it is easy to form a compact fixing device including a rotatable endless fixing member.

(Aspect C)
In (Aspect A) or (Aspect B), the heating means has a plurality of fixing heat sources such as a first halogen heater 102A and a second halogen heater 102B each having a different heat distribution in the longitudinal direction. It is characterized by.
According to this, as described in the present embodiment, it is possible to efficiently heat the fixing member range corresponding to the recording material size of the recording material passing inside the region heated by the end heat source.

(Aspect D)
In (Aspect C), the plurality of fixing heat sources are arranged on the inner peripheral side of the fixing member, and are separated from each other by a shielding member such as a stay 107 or a reflecting member 109.
According to this, as described in the present embodiment, the following effects can be achieved.
Since heating is not performed when the heater is turned on as in the conventional configuration, a part of the fixing heat source such as the glass tube is not heated, so that the heating efficiency is not lowered.

(Aspect E)
In any one of (Aspect A) to (Aspect D), at least one end heater inner end notch 126d in the longitudinal direction center side of the heat transfer assisting member from the position where the end heat source abuts. A portion having a low cross-sectional second moment, for example, is provided.

According to this, as described in the present embodiment, the following effects can be achieved.
Normally, when the heat transfer assisting member is deformed so as to be twisted with respect to the pressing member, the heat transfer assisting member and the end heat source are likely to be in point contact where the contact points 106d and the like are formed. And heat transfer of the end heat source may be deteriorated.
On the other hand, even when the heat transfer assisting member is deformed so as to be twisted with respect to the pressing member by providing a portion that is easily deformed on the center side in the longitudinal direction from the position where the end heat source of the heat transfer assisting member abuts. The end heat source contact position of the heat transfer assisting member pressed by the pressing member is easily deformed.
Therefore, the heat transfer auxiliary member and the end heat source are easily brought into close contact with each other at the end heat source contact position, and the possibility that heat transfer between the heat transfer auxiliary member and the end heat source is deteriorated can be solved.

(Aspect F)
In any one of (Aspect A) to (Aspect E), a portion having a low cross-sectional secondary moment, such as providing an end heater portion notch 126e in a contact range of the heat transfer assisting member with the end heat source. A plurality of locations are provided.

According to this, as described in the present embodiment, the following effects can be achieved.
Usually, when the flatness of the contact range between the heat transfer assisting member and the end heat source is poor, the heat transfer assisting member and the end heat source are hardly in close contact with each other, and heat transfer between the heat transfer assisting member and the end heat source is deteriorated.
On the other hand, even if the flatness of the contact range between the heat transfer auxiliary member and the end heat source is poor and it is difficult to adhere to the heat transfer auxiliary member by contacting the end heat source with the end heat source, the flatness Adhesion can be improved by making it possible to correct by following the shape of the end heat source.
Therefore, the heat transfer auxiliary member and the end heat source are easily brought into close contact with each other at the end heat source contact position, and the possibility that heat transfer between the heat transfer auxiliary member and the end heat source is deteriorated can be solved.
Moreover, the heat transfer efficiency can be expected to be improved due to the heat capacity reduction effect of the heat transfer assisting member by providing a plurality of portions having a low section moment in the contact range of the heat transfer assisting member with the end heat source.

(Aspect G)
In any one of (Aspect A) to (Aspect F), in a region in contact with the end heat source, the thickness of the heat transfer auxiliary member such as the left contact portion 116a or the right contact portion 116b is set to the thickness of the heat. It is characterized by being made thinner than a plate thickness such as a plate thickness t2 on the center side in the longitudinal direction of the movement assisting member.
According to this, as described in the present embodiment, by making the vicinity of the end heat source of the heat transfer auxiliary member thin, it has deformation flexibility, and it is easy to correct even in a state where flatness such as torsion and undulation is poor. Thus, the contact with the end heat source is improved. Further, since the heat transfer assisting member has a low heat capacity due to the thinning, it can be rapidly heated by the end heat source, and the warm-up time can be shortened even when passing the Nobi paper such as A3 Nobi paper.

(Aspect H)
In an image forming apparatus such as a printer 200 provided with a fixing device that fixes a toner image formed on a recording material such as paper P onto the recording material, the fixing device includes (Aspect A) to (Aspect G). A fixing device such as any one of the fixing devices 100 is provided.
According to this, as described in the present embodiment, it is possible to provide an image forming apparatus that can achieve the same effects as any of the fixing devices of (Aspect A) to (Aspect G).
In addition, an image forming apparatus excellent in energy saving can be provided.

100 fixing device 101 fixing belt 102 halogen heater 102A first halogen heater 102B second halogen heater 103 pressure roller 104 elastic rubber layer 105 cored bar 105a bearing 106 nip forming member 106a left recess 106b right recess 106c opposed reference surface 106d current contact 107 Stay 107A First member 107B Second member 109 Reflective member 116 Heat transfer assisting member 116a Left contact portion 116b Right contact portion 116c Opposing surface 126 End heater 126a Left end heater 126b Right end heater 126d End heater inner end notch 126e End Heater notch 136a Left temperature detection means 136b Right temperature detection means 200 Printer N Nip part P Paper

JP 2014-178370 A JP 2014-056203 A

Claims (8)

A rotatable endless fixing member, heating means for heating the fixing member at a non-nip portion, a nip forming member disposed on the inner peripheral side of the fixing member, and a recording material nipped and conveyed by the fixing member A fixing device comprising: a pressing member that presses the fixing member toward the fixing member; and an end heat source that heats the vicinity of both ends of the fixing member at a nip portion.
A heat transfer auxiliary member for assisting heat transfer in the longitudinal direction of the fixing member at a nip portion formed between the fixing member and the pressing member is provided on the fixing member side of the nip forming member, and the nip forming member And the end heat source at both ends in the longitudinal direction between the heat transfer assisting member and
The fixing device, wherein the contact portion of the heat transfer auxiliary member with the end heat source is configured to be deformable with a stress smaller than a pressing force by the pressing member. The fixing device according to claim 1,
The fixing device according to claim 1, wherein the heating unit is disposed on an inner peripheral side of the fixing member. The fixing device according to claim 1 or 2,
The fixing device according to claim 1, wherein the heating unit includes a plurality of fixing heat sources each having a different heat distribution in the longitudinal direction. The fixing device according to claim 3.
The fixing device, wherein the plurality of fixing heat sources are arranged on an inner peripheral side of the fixing member and are separated from each other by a shielding member. In the fixing device according to any one of claims 1 to 4,
A fixing device, wherein a portion having a low second moment of section is provided in at least one position on a center side in the longitudinal direction of the heat transfer assisting member from a position where the end heat source contacts. In the fixing device according to any one of claims 1 to 5,
A fixing device comprising a plurality of portions having a low second moment of section in a contact range of the heat transfer auxiliary member with the end heat source. The fixing device according to any one of claims 1 to 6,
The fixing device according to claim 1, wherein a thickness of the heat transfer assisting member is made thinner than a thickness of the heat transfer assisting member on a center side in a longitudinal direction in a region in contact with the end heat source. In an image forming apparatus comprising a fixing device for fixing a toner image formed on a recording material onto the recording material,
An image forming apparatus comprising the fixing device according to claim 1 as the fixing device.

Images