JP2021179536A - Fixing device and image forming apparatus - Google Patents

Abstract

To provide a fixing device that can reduce a pressure transmitted to a soaking member from another member to reduce damage to and rupture of the soaking member, and can satisfactorily maintain a state of contact between the soaking member and a supporting member.SOLUTION: A fixing device comprises: a fixing member 21; a pressure member; a nip forming member 50; a supporting member 26; a heat generation unit 23; a reflecting member 25; a soaking member 27 that is in contact with the supporting member 26; and a buffer member 29 that is in contact with the soaking member 27 from an opposite side of a side of the soaking member 27 in contact with the supporting member 26. The soaking member 27 and the buffer member 29 are arranged between the nip forming member 50 and the supporting member 26, and the buffer member 29 is in contact with the nip forming member 50.SELECTED DRAWING: Figure 3

Description

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

In the prior art, graphene (heat equalizing member) is brought into contact with a stay (support member) that becomes hot due to heat transfer from the heater, and the stay temperature is equalized to prevent deformation of other contact members such as nip forming members. It has been known.

In order to equalize the heat of a hard individual stay with a hard individual heat equalizing member such as graphene, a fine air layer is created between the heat equalizing member and the stay unless they are brought into contact with each other under a certain amount of pressure, and the contact area. There is a problem that the heat transfer property deteriorates due to the decrease in heat transfer. However, when pressure is applied to the heat equalizing member, the heat equalizing member may be deformed and damaged.

Patent Document 1 discloses that a high heat conductive member as a heat equalizing member is installed between an elongated heater whose longitudinal direction is orthogonal to the paper transport direction and a heater support member that supports the heater. .. According to Patent Document 1, by defining the relationship between the shapes of the heater support member and the high heat conductive member, it is possible to easily confirm that the high heat conductive member is accurately sandwiched between the heater support member and the heater. It is said that it can be easily confirmed that there is no breakage, tearing, bending, etc. of the high thermal conductive member.

However, the prior art has not solved the problem that the heat equalizing member is damaged or torn due to the pressure from other members such as the nip forming member. If the heat equalizing member is damaged or torn, the contact state with the support member deteriorates, and the heat transfer efficiency deteriorates.

Therefore, the present invention can reduce the pressure transmitted from other members to the heat equalizing member, reduce damage or tearing of the heat equalizing member, and can maintain a good contact state between the heat equalizing member and the support member. It is an object of the present invention to provide a fixing device.

In order to solve the above problems, the fixing device of the present invention is a pressurizing member that presses and contacts the fixing member and the fixing member to fix an unfixed image on a recording medium conveyed between the fixing members. A nip forming member that abuts on the fixing member from the inside to form a fixing nip between the fixing member and the pressurizing member, and a nip forming member provided inside the fixing member that abuts and supports the nip forming member. The support member, the heat generating portion provided inside the fixing member and radiating heat, the reflective member that abuts on the support member and reflects the radiant heat from the heat generating portion to the fixing member, and the support member. The heat equalizing member and the cushioning member that abuts on the heat equalizing member from the side opposite to the side that abuts on the support member in the heat equalizing member are provided, and the heat equalizing member and the cushioning member are the nip forming member. It is arranged between the support member and the support member, and the cushioning member is characterized in that it abuts on the nip forming member.

According to the present invention, it is possible to reduce the pressure transmitted from other members to the heat equalizing member, reduce damage or tearing of the heat equalizing member, and maintain a good contact state between the heat equalizing member and the support member. It is possible to provide a fixing device that can be used.

It is a schematic block diagram which shows an example of the image forming apparatus of this invention. It is a figure which shows the cross section of an example of a fixing device. It is schematic cross-sectional view of the main part which shows an example of the fixing device of this invention. It is a plan view (A) and (B) of an example of a support member, a heat soaking member and a cushioning member. It is schematic cross-sectional view of the main part for demonstrating an example of the contact point between a heat equalizing member and a support member. It is a schematic cross-sectional view (A) and (B) of the main part for demonstrating another example of the contact point between a heat equalizing member and a support member. It is a schematic sectional view (A) and (B) of the main part which shows the other example of the fixing apparatus of this invention. It is sectional drawing of the main part which shows the comparative example 1. FIG. It is sectional drawing of the main part which shows the comparative example 2. FIG. It is sectional drawing of the main part which shows the comparative example 3. FIG. 2A and 2B are schematic cross-sectional views of a main part showing Comparative Example 4.

Hereinafter, the fixing device and the image forming device according to the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to the embodiments shown below, and can be modified within the range conceivable by those skilled in the art, such as other embodiments, additions, modifications, and deletions. However, as long as the action and effect of the present invention are exhibited, it is included in the scope of the present invention.

The fixing device of the present invention has a fixing member, a pressure member that presses against the fixing member to fix an unfixed image on a recording medium conveyed between the fixing member, and the fixing member from the inside. A nip forming member that abuts to form a fixing nip between the fixing member and the pressurizing member, a support member provided inside the fixing member that abuts and supports the nip forming member, and the fixing member. A heat generating portion that is provided inside and radiates heat, a reflective member that abuts on the support member and reflects the radiant heat from the heat generating portion to the fixing member, a heat equalizing member that abuts on the support member, and the heat equalizing member. A cushioning member that abuts on the heat equalizing member from a side opposite to the side that abuts on the support member in the member is provided, and the heat equalizing member and the cushioning member are placed between the nip forming member and the support member. Disposed, the cushioning member is characterized in contact with the nip forming member.

(First Embodiment)
FIG. 1 is a schematic configuration diagram showing an example of a printer 100 in which the fixing device 20 according to the present embodiment is used.

As shown in FIG. 1, the printer 100 as an image forming apparatus includes an image forming apparatus 101 including a photoconductor drum 1 as an image carrier, a fixing apparatus 20, and the like.

The printer 100 has a charging roller 2 as a charging means, an optical writing unit 3 provided with a mirror 3A, a developing means 4 provided with a developing roller 4A, and a transfer charger around the photoconductor drum 1 in the order of rotation in the clockwise direction. The provided transfer means 5, cleaning means 14, and the like are arranged.

When the photoconductor drum 1 is rotationally driven clockwise by the driving means, the surface of the photoconductor drum 1 is uniformly charged by the charging roller 2. When the charged portion of the photoconductor drum 1 reaches the light writing unit 3, the printer 100 irradiates the exposure light through the mirror 3A by the light writing unit 3. As a result, an electrostatic latent image corresponding to the image to be created is formed on the photoconductor drum 1. When the formed electrostatic latent image reaches the developing position, the printer 100 visualizes the electrostatic latent image with the developer (toner) of the developing means 4 to obtain a toner image.

Then, the toner image arrives at a position where the transfer means 5 faces. The transfer means 5 is not limited to the transfer charger, and a transfer roller, a transfer brush, a transfer belt, or the like can be used.

The printer 100 arranges the paper feeding means 10 below the photoconductor drum 1. The paper feed means 10 separates and feeds the paper feed tray 11 in which the paper P as a sheet-shaped recording medium is stored in a loaded state and the paper P stored in the paper feed tray 11 one by one in order from the top. It has a paper feed roller 12 and the like.

The paper P sent out by the paper feed roller 12 is conveyed to the photoconductor drum 1 via the pair of timing transfer rollers 13. At that time, the paper P is abutted against the timing transfer roller 13 and temporarily stopped, and after the posture deviation is corrected, the paper P is sent out at a timing synchronized with the rotation of the photoconductor drum 1. That is, the toner image formed on the photoconductor drum 1 is fed to the transfer unit 102 by the timing transfer roller 13 at the timing when the tip of the toner image and the predetermined position of the tip of the paper P in the transport direction coincide with each other.

The transfer means 5 transfers the toner image formed on the photoconductor drum 1 by applying the transfer bias onto the paper P that has entered the transfer unit 102. The paper P on which the toner image is transferred is conveyed toward the fixing device 20. After the paper P is fixed by the fixing device 20, the paper P is ejected and stacked in the paper ejection tray.

On the other hand, the toner remains on the photoconductor drum 1 after transfer. The cleaning means 14 cleans the residual toner on the photoconductor drum 1 by scraping it off with a cleaning blade 15.

After that, the residual potential on the photoconductor drum 1 is removed by the static elimination means to prepare for the next image forming step.

Next, the fixing device 20 will be described.
FIG. 2 is a diagram showing a cross section of the fixing device 20. As shown in FIG. 2, the fixing device 20 press-contacts the fixing belt 21 as a fixing member and the fixing belt 21 arranged opposite to each other to form a fixing nip SN, and conveys the fixing device 20 between the fixing belt 21 and the fixing belt 21. A pressurizing roller 22 as a pressurizing member for fixing an unfixed image (toner image) on the paper P to be formed is provided. Further, the fixing device 20 includes a heating unit 23 that heats the fixing belt 21 from the inside.

The pressure roller 22 is rotatably arranged to face the fixing belt 21. The pressure roller 22 has an iron core metal 22A and an elastic layer 22B coated on the surface of the core metal 22A. The elastic layer 22B is made of silicone rubber. It is desirable to form a fluororesin layer on the surface of the elastic layer 22B in order to improve the releasability. The pressure roller 22 is pressed against the fixing belt 21 by the urging means.

The fixing belt 21 plays a role of melting the toner of the paper P on which the toner image is transferred and a role of forming a fixing nip SN together with the pressure roller 22. When the paper P on which the toner image (unfixed image) is placed passes through the fixing nip SN, the toner is melted by the heat of the preheated fixing belt 21 in the fixing nip SN, and the toner is pressed by the paper P. Is fixed in.

The fixing belt 21 has a substrate and an elastic layer coated on the surface of the substrate. The elastic layer is made of silicone rubber. A mold release layer made of a fluororesin such as PFA or PTFE is formed on the surface of the fixing belt 21 in order to enhance durability and ensure mold release. The substrate of the fixing belt 21 is not limited to stainless steel, and may be a substrate made of nickel, polyimide, or the like.

The heating unit 23 includes a resistance heat generation unit 24 which is a heat generation unit and a reflection member 25, and heats the fixing belt 21. The resistance heating unit 24 is composed of a heating element such as a lighting element. The heating element may be composed of a ceramic heater or the like. A power supply 33 is connected to the resistance heat generation unit 24, and power is supplied from the power supply 33 to the resistance heat generation unit 24. The output of the power supply 33 is controlled by the external control means 32. The external control means 32 is composed of a microcomputer including a CPU, a ROM, a RAM, an I / O interface, and the like.

The reflective member 25 is, for example, a plate-shaped member made of an aluminum material, and is formed in a substantially V shape in a side view. The reflective member 25 reflects the heat radiated by the lighting of the resistance heating unit 24 and efficiently transfers the heat to the fixing belt 21.

Further, a fixing support member 28 is provided inside the fixing belt 21. The fixing support member 28 is connected to the side plate of the fixing device 20 to support the fixing belt 21. More specifically, the fixing support member 28 plays a role of determining the shape of the cross section of the fixing belt 21, and is provided at both ends of the fixing belt 21. It should be noted that even in a configuration in which a cylindrical member such as a pipe is arranged between the fixing support members 28 provided at both ends of the fixing belt 21 and the fixing belt 21, the cross-sectional shape is determined over the entire longitudinal direction of the fixing belt 21. good.

Further, a nip forming member 50 is installed at a position of the fixing nip SN inside the fixing belt 21. Further, inside the fixing belt 21, a support member 26 that abuts on the nip forming member 50 to support the nip forming member 50 is installed. The support member 26 is attached to the side plate of the fixing device 20 by a metal stay member. The support member 26 is a sheet metal formed in a substantially U shape in a side view.

The reflective member 25 is, for example, fixed to the upper surface of a substantially U-shaped support member 26 by screwing to a substantially central portion in the longitudinal direction, which is a direction orthogonal to the transport direction of the paper P.

The nip forming member 50 abuts from the inside of the fixing belt 21 and plays a role of determining the fixing nip SN indicating the contact width between the fixing belt 21 and the pressure roller 22. The shape of the fixing nip SN is arbitrary, but it may be flat with respect to the paper passing direction of the paper P, or may have a shape such that only the outlet has a high pressure. Further, the nip forming member 50 is in contact with the inner surface of the fixing belt 21. Therefore, the nip forming member 50 is required to have heat insulating properties, and is made of, for example, a resin. Therefore, the heat resistant temperature of the nip forming member 50 is the lowest inside the fixing belt 21.

Here, a conventional problem (excessive heat resistant temperature inside the fixing belt 21) will be briefly described.

The fixing device 20 lights the resistance heating unit 24 before the paper P on which the toner image (unfixed image) is placed passes through the fixing nip SN along the paper passing direction. By lighting the resistance heating unit 24, heat is radiated in all directions. Further, the reflective member 25 reflects the heat radiated by the lighting of the resistance heating unit 24 toward the fixing belt 21 to be heated.

By the way, when printing a large amount of paper P, the resistance heating unit 24 is continuously lit to compensate for the amount of heat taken away by the passage of paper P. At this time, the temperature inside the fixing belt 21 becomes very high. Further, the reflective member 25 cannot reflect all the radiated heat, and the reflective member 25 including the convection of heat also becomes extremely hot.

As described above, the reflective member 25 is screwed to a substantially central portion of the upper surface of the substantially U-shaped support member 26 in the longitudinal direction. Therefore, when the heat of the reflective member 25 is transferred from the screwed portion to the support member 26, the heat is finally transferred to the nip forming member 50. When the heat of the reflective member 25 is transferred from the screwed portion to the support member 26, the temperature distribution of the support member 26 is high in the center and low in the end portion. At this time, if the temperature at the center of the support member 26 becomes too high, the heat resistant temperature inside the fixing belt 21 exceeds the heat resistant temperature of the nip forming member 50, which causes a problem that the nip forming member 50 melts.

Even if the reflective member 25 is fixed to the longitudinal end of the support member 26 by screwing, such a problem cannot be solved. If the reflective member 25 is screwed to the end portion of the support member 26 in the longitudinal direction, it is possible to prevent the center of the support member 26 from becoming hot. However, when the narrow paper P is passed, the amount of heat taken away at the portion where the paper P passes and the portion where the paper P does not pass is different, so that the fixing belt 21 is transferred between the center and the end of the support member 26. A phenomenon with different heat distribution occurs. Such a large temperature difference between the center and the end of the support member 26 may affect the image quality, and has a side effect of causing a problem other than the temperature rise of the support member 26.

Therefore, it is important to smooth the temperature distribution as much as possible in order to solve the heat-resistant temperature excess due to the temperature rise inside the fixing belt 21.
Therefore, in the present embodiment, a heat equalizing member for smoothing the internal temperature of the fixing belt 21 is provided. In the present embodiment, for example, one plate-shaped member extending over both ends of the support member 26 in the longitudinal direction is used as the heat equalizing member, and the temperature distribution of the support member can be made uniform by abutting the support member. .. Further, by using the heat equalizing member, the internal temperature distribution of the fixing belt 21 can be smoothed. Note that FIG. 2 omits the illustration of the heat equalizing member.

However, a method of bringing the heat equalizing member into contact with the support member and a method of fixing the heat equalizing member are important, and if these methods are not properly selected, the effect of providing the heat equalizing member cannot be sufficiently obtained. In the prior art, good adhesion between a heat soaking member such as graphene, which is a high thermal conductive material, and a supporting member cannot be realized.

Here, Comparative Example 1 not included in the present embodiment will be described. FIG. 8 is a diagram for explaining the present comparative example, and is a schematic view showing a cross section of the vicinity of the fixing belt of the fixing device. Examples of the heat equalizing member 27 include a member extending in the axial direction (also referred to as a longitudinal direction) of the fixing belt 21, and when the member is to be inserted between the support members 26, it cannot be inserted without the gap 40. Therefore, due to the presence of the gap 40, the gap 40 is insulated and the heat from the support member 26 is less likely to be transferred to the heat equalizing member 27.

Further, Comparative Example 2 not included in the present embodiment will be described. FIG. 9 is a diagram for explaining the present comparative example, and is a diagram showing a cross section in the vicinity of the fixing belt of the fixing device as in FIG. In order to equalize the heat of the support member of a hard solid using a heat equalizing member of a hard solid such as graphene, a fine air layer is formed between the heat equalizing member and the support member unless they are brought into contact with each other under a certain pressure. It will occur. When an air layer is formed, the contact area between the heat soaking member and the supporting member is reduced, and the heat transfer property is deteriorated.

However, when the heat equalizing member 27 is arranged at the position where the nip forming member 50 abuts as in this comparative example, the heat in the vicinity of the nip forming member 50 in the support member 26 is equalized, so that the efficiency is good, but the heat equalizing is good. The pressure applied to the member 27 becomes too strong, and the heat equalizing member 27 is deformed. As a result, the contact area with the support member 26 is reduced, the heat transfer efficiency is lowered, and the heat equalizing member 27 is damaged or torn.

Therefore, in the present embodiment, a cushioning member is used to disperse the pressure applied to the heat equalizing member 27 to prevent the heat equalizing member 27 from being damaged or torn. By using a cushioning member to apply pressure to the entire heat equalizing member 27, the contact pressure between the heat equalizing member 27 and the support member 26 can be made uniform, and heat conduction can be further promoted.

FIG. 3 is a diagram for explaining the present embodiment, and is a diagram showing a cross section in the vicinity of the fixing belt of the fixing device as in FIG. 8 and the like. The fixing support member 28 is not shown for the sake of simplicity, and the fixing portion of the reflective member 25 with the support member 26 is not shown.

In the present embodiment, the heat equalizing member 27 that abuts on the support member 26 and the cushioning member 29 that abuts on the heat equalizing member 27 from the side opposite to the side of the heat equalizing member 27 that abuts on the support member 26 are shown. The heat soaking member 27 and the cushioning member 29 are arranged between the support member 26 and the nip forming member 50.

In the present embodiment, the nip forming member 50 presses the heat soaking member 27 and the cushioning member 29 against the support member 26 from the cushioning member 29 side. As a result, the heat equalizing member 27 can be brought into contact with the support member 26, and the heat of the support member 26 can be conducted to the heat equalizing member 27.

By providing the cushioning member 29 between the heat equalizing member 27 and the nip forming member 50, the pressure from the nip forming member 50 can be dispersed and the heat equalizing member 27 can be brought into contact with the support member 26 at an appropriate pressure. can. Further, even when a material brittle in composition is used as the heat equalizing member 27, the heat equalizing member 27 can be prevented from being damaged or torn, and vibration from the nip forming member 50 is absorbed and the member slides. It is possible to reduce fluctuations in pressing pressure due to vibration and passage of a recording medium. As a result, the pressure and vibration transmitted from the nip forming member 50 to the heat equalizing member 27 can be reduced, the deformation and damage of the heat equalizing member 27 can be reduced, and the contact state between the heat equalizing member 27 and the support member 26 can be improved. Can be maintained.

The heat equalizing member 27 is made of, for example, a high heat conductive material. The heat soaking member 27 in this embodiment can be formed of, for example, copper, aluminum or graphene. Graphene is a sheet-like substance formed by bonding carbon atoms.

As the cushioning member 29, for example, a material containing a large amount of air can be used, and heat transfer from the heat soaking member 27 to the nip forming member can be suppressed by enhancing the heat insulating property. Further, by using a material having a low thermal conductivity as the cushioning member 29, it is possible to reduce the heat transfer from the heat equalizing member to the nip forming member.
As the material of the cushioning member 29, for example, highly heat-resistant silicone rubber or the like can be used.

An example of the shape of the heat soaking member 27 and the cushioning member 29 of the present embodiment will be described with reference to FIG. FIG. 4A is a schematic plan view of the support member 26 when viewed from the direction A in FIG. Further, FIG. 4B is a schematic plan view of the support member 26, the heat soaking member 27, and the cushioning member 29 when viewed from the direction B of FIG.

As shown in the present embodiment, the heat soaking member 27 and the cushioning member 29 have a single plate shape extending over both ends of the support member 26 in the longitudinal direction (direction orthogonal to the transport direction of the paper P). It is a member. In a plan view, the areas of the heat soaking member 27 and the cushioning member 29 may be the same, or the cushioning member 29 may be smaller as shown in FIG. 4B. When the area of the cushioning member 29 is small, as shown in FIG. 3, even when the shape of the cushioning member 29 changes due to the pressure from the nip forming member 50, the surplus region does not come into contact with the protrusion 50a (described later). Can be secured.

In the above, the heat soaking member 27 and the cushioning member 29 are formed as one plate-shaped member, but the present invention is not limited to this, and the heat soaking member 27 and the cushioning member 29 may be divided into a plurality of members. For example, the heat soaking member 27 and the cushioning member 29 may be divided into two in the vicinity of the substantially central portion in the longitudinal direction of the support member 26, or may be further divided into a plurality of members. Further, only the cushioning member 29 may be divided.

In the present embodiment, the nip forming member 50 has one or more protrusions 50a on the side that abuts on the support member 26, and abuts on the support member 26 via the protrusions 50a. For example, in the nip forming member 50 of FIG. 3, two protrusions 50a are provided, and are partially in contact with the support member 26 via the two protrusions 50a. With such a configuration, it is possible to prevent the heat equalizing member 27 from being excessively pressed by the nip forming member 50, and it is possible to further suppress deformation, breakage and tearing of the heat equalizing member.

Further, by providing a protrusion on the nip forming member and causing the nip forming member to come into contact with the support member via the protrusion, the pressure transmitted from the nip forming member to the heat soaking member and the cushioning member can be reduced. Then, by providing the cushioning member, the reduced pressure from the nip forming member is applied to the heat equalizing member in an appropriate state, and the heat equalizing member is pressed against the support member with a light pressure, so that the heat equalizing member and the support member are pressed. It is possible to maintain a good contact state with.

As described above, according to the fixing device of the present embodiment, the pressure transmitted from other members to the heat equalizing member can be reduced, and the damage or tearing of the heat equalizing member can be reduced. The contact state can be maintained well. Further, according to the image forming apparatus of the present embodiment, in addition to preventing defects due to a partial temperature rise of the member, the effect of the fixing apparatus of the present embodiment can be obtained.

(Second embodiment)
Next, another embodiment of the fixing device according to the present invention will be described. Descriptions of the same items as in the above embodiment will be omitted.

In this embodiment, a lubricant is applied between the support member and the heat soaking member. By using a lubricant, it is possible to eliminate poor contact due to unevenness and distortion of both the heat equalizing member and the support member, and eliminate fine non-contact parts, so the contact area is maximized and heat is dispersed more evenly. be able to. Therefore, the temperature distribution of the support member can be further reduced.

FIG. 5 shows a schematic view when a lubricant is applied. FIG. 5 shows a cross-sectional view similar to that of FIG. 3, and is an enlarged schematic view of a main part. As shown in the figure, the lubricant 30 is applied between the support member 26 and the heat equalizing member 27, so that the support member 26 and the heat equalizing member 27 can be brought into good contact with each other.

Another figure in this embodiment is shown in FIG. FIG. 6 is a schematic cross-sectional view for explaining the contact points between the support member 26 and the heat soaking member 27.
As shown in FIG. 6A, according to the present embodiment, for example, even when the heat soaking member 27 is slanted with respect to the contact surface of the support member 26, the contact with the support member 26 An area can be secured and heat conduction can be performed uniformly. Further, as shown in FIG. 6B, even when the surface of the heat equalizing member 27 has irregularities, the contact area with the support member 26 can be secured, and heat conduction can be performed uniformly. can.

As the lubricant, for example, grease or the like can be used. The thermal conductivity of the lubricant is preferably 1 W / m · K or more. When the lubricant has high thermal conductivity, the heat equalizing effect of the heat equalizing member can be improved.

(Third embodiment)
Next, another embodiment of the fixing device according to the present invention will be described. Descriptions of the same items as in the above embodiment will be omitted.

In the above embodiment, an example in which a heat equalizing member and a cushioning member are provided between the support member and the nip forming member has been described, but the present invention is not limited to this, and the installation location may be changed. .. For example, a heat equalizing member may be provided on the side surface of the support member. Even in such a case, the effect of reducing the bias of the temperature distribution of the support member can be obtained.

First, Comparative Example 3 not included in the present embodiment will be described. FIG. 10 is a diagram for explaining the present comparative example, and is a diagram showing a cross section in the vicinity of the fixing belt of the fixing device as in FIG. In this comparative example, the heat equalizing member 27 is attached to the attachment portion 26a of the support member 26 via the heat-resistant adhesive 34. Since the heat-resistant adhesive 34 is not malleable, the layer becomes thick when it is provided between the heat equalizing member 27 and the support member 26. As the adhesive layer becomes thicker, the heat conduction from the support member 26 to the heat equalizing member 27 deteriorates, and the effect of reducing the bias of the temperature distribution of the support member 26 diminishes. On the other hand, when the amount of the heat-resistant adhesive 34 applied is reduced and the heat-resistant adhesive 34 is applied thinly, the heat soaking member 27 comes off due to poor adhesion.

To solve the above problem, it is conceivable to fix the heat equalizing member by using a locking member such as a screw without using an adhesive. Comparative Example 4 which is not included in the present embodiment will be described in consideration of this point. FIG. 11 is a diagram for explaining this comparative example, and FIG. 11A is a diagram showing a cross section in the vicinity of the fixing belt of the fixing device as in FIG. 11 (B) is an enlarged schematic view of a main part of FIG. 11 (A).

As shown in FIG. 11A, the heat equalizing member 27 is attached to the attachment portion 26a of the support member 26 via the locking member 31.
However, if a brittle material is used as the heat soaking member 27, as shown in FIG. 11B, cracks 60 are formed, breakage or tearing occurs, and good adhesion to the support member cannot be obtained.

Therefore, in the present embodiment, when the locking member is used, the heat equalizing member is fixed to the support member via the cushioning member. In the present embodiment, the support member has a plurality of surfaces and is in contact with the nip forming member on one surface. The heat equalizing member abuts on the support member on a surface other than the surface where the support member abuts on the nip forming member (also referred to as a contact surface), and is fixed by the locking member via the cushioning member. As a result, it is possible to suppress the occurrence of cracks in the heat soaking member and maintain good adhesion.

That is, the fixing device of the present embodiment includes a fixing member, a pressure member that presses against the fixing member and fixes an unfixed image on a recording medium conveyed between the fixing members, and the fixing member. A nip forming member that abuts from the inside to form a fixing nip between the fixing member and the pressurizing member, a support member provided inside the fixing member that abuts and supports the nip forming member, and the above. A heat generating portion provided inside the fixing member to radiate heat, a reflecting member that abuts on the support member and reflects the radiant heat from the heat generating portion to the fixing member, and a heat equalizing member that abuts on the support member. The heat soaking member includes a cushioning member that comes into contact with the heat equalizing member from a side opposite to the side that comes into contact with the support member, and the support member has a plurality of surfaces, and the nip is formed on one surface. The heat soaking member abuts on the support member on a surface other than the surface where the support member abuts on the nip forming member, and is fixed by the locking member via the cushioning member. It is a feature.

FIG. 7 is a diagram for explaining the present embodiment, and is a diagram showing a cross section of the fixing device 20 in the vicinity of the fixing belt 21 as in FIG. Here, too, the fixing support member 28 is not shown for simplicity of explanation, and the fixing portion of the reflective member 25 with the support member 26 is not shown.

As shown in FIGS. 7A and 7B, the heat soaking member 27 abuts on the support member on a surface other than the surface (contact surface 26c) where the support member 26 abuts on the nip forming member 50. , It is fixed by the locking member 31 via the cushioning member 29.

In FIG. 7A, the heat equalizing member 27 is attached to the outer wall side of the attachment portion 26a of the support member 26. The present embodiment is not limited to this, and as shown in FIG. 7B, the heat equalizing member 27 may be attached to the inner wall side of the attachment portion 26a in the support member 26.

The heat soaking member 27 and the cushioning member 29 may be provided not on the mounting portion 26a but on the mounting portion 26b, or may be provided on both the mounting portion 26a and the mounting portion 26b. Considering the heat transfer route, it is effective to provide the heat equalizing member 27 in the mounting portion 26a to which the reflecting member 25 is mounted.

20 Fixing device 21 Fixing member 22 Pressurizing member 24 Heat generating part 25 Reflecting member 26 Supporting member 26a, 26b Mounting part 26c Contact surface 27 Heat equalizing member 29 Cushioning member 30 Lubricant 31 Locking member 34 Heat-resistant adhesive 40 Gap 50 Nip Forming member 60 Crack 100 Image forming device

Japanese Unexamined Patent Publication No. 2015-219948

Claims (7)

With the fixing member
A pressure member that presses against the fixing member and fixes an unfixed image on a recording medium that is conveyed between the fixing member and the pressing member.
A nip forming member that abuts on the fixing member from the inside to form a fixing nip between the fixing member and the pressure member.
A support member provided inside the fixing member and supporting the nip forming member in contact with the nip forming member.
A heat generating portion provided inside the fixing member and radiating heat,
A reflective member that comes into contact with the support member and reflects radiant heat from the heat generating portion to the fixing member.
A heat equalizing member that comes into contact with the support member and
The heat soaking member includes a cushioning member that comes into contact with the heat soaking member from a side opposite to the side that comes into contact with the support member.
The heat soaking member and the cushioning member are arranged between the nip forming member and the support member.
The fixing device is characterized in that the cushioning member comes into contact with the nip forming member. The fixing device according to claim 1, wherein the nip forming member has one or more protrusions on a side that comes into contact with the support member, and comes into contact with the support member via the protrusions. With the fixing member
A pressure member that presses against the fixing member and fixes an unfixed image on a recording medium that is conveyed between the fixing member and the pressing member.
A nip forming member that abuts on the fixing member from the inside to form a fixing nip between the fixing member and the pressure member.
A support member provided inside the fixing member and supporting the nip forming member in contact with the nip forming member.
A heat generating portion provided inside the fixing member and radiating heat,
A reflective member that comes into contact with the support member and reflects radiant heat from the heat generating portion to the fixing member.
A heat equalizing member that comes into contact with the support member and
The heat soaking member includes a cushioning member that comes into contact with the heat soaking member from a side opposite to the side that comes into contact with the support member.
The support member has a plurality of surfaces, and abuts on the nip forming member on one surface.
The fixing device is characterized in that the heat soaking member abuts on the support member on a surface other than the surface where the support member abuts on the nip forming member, and is fixed by the locking member via the cushioning member. .. The fixing device according to any one of claims 1 to 3, wherein a lubricant is applied between the support member and the heat soaking member. The fixing device according to claim 4, wherein the lubricant has a thermal conductivity of 1 W / m · K or more. The fixing device according to any one of claims 1 to 5, wherein the heat equalizing member is copper, aluminum, or graphene. An image forming apparatus comprising the fixing apparatus according to any one of claims 1 to 6.

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