JP2001265153A - Fixing machine and image forming device provided with the fixing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing machine where improvement of ability to separate of a recording medium after being passed through a nip with a fixing body or a pressing body is achieved and image failure due to foreign matters such as oil, toner and paper powder that is attached to a separating member, and to provide an image forming device equipped with the fixing machine. SOLUTION: In the machine, a separation claw 123 is provided with a radius of curvature that is 100 μm or smaller in a section that is perpendicular to axial direction of a fixing roll 20 in an abutting part with the fixing roll 20, and the separating claw 123 has a projecting part formed on a surface that is faced to the nip side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device provided in an image forming apparatus employing an electrophotographic system, an electrostatic recording system, a magnetic photographic system, and the like, and an image forming apparatus provided with the fixing device.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus employing an electrophotographic system, an electrostatic recording system, a magnetic photographic system or the like, a pair of rollers (fixing roller, roller Pressure roller) and a heating means for heating the fixing roller, and a transfer material as a recording medium such as plain paper or photosensitive paper carrying a toner image as an unfixed image is formed by the fixing roller and the pressure roller. A fixing device for fixing the toner image to the transfer material by nipping and conveying the nip and applying heat and pressure, wherein the fixing roller or the pressure is applied to at least one peripheral surface of the fixing roller and the pressure roller. A separating portion having a contact portion extending in the axial direction of the roller and separating the transfer material after passing the nip from the surface of the fixing roller or the pressure roller by contact with the fixing roller or the pressure roller; Are fixing apparatus known comprising a barrel separation claw, has been put to practical use.

In such a fixing device, a separation claw is generally provided in contact with at least one surface of a fixing roller and a pressure roller in the vicinity of a transfer material discharge side nip. The fixing member is always in contact with at least one surface of the pressure roller, and is attached for the purpose of preventing trouble caused by the transfer material having passed through the nip being wound around the fixing roller or the pressure roller. In general, the separation claw is formed such that a cross section perpendicular to the axial direction of the fixing roller or the pressure roller at the front end portion which is a contact portion with the fixing roller or the pressure roller (hereinafter, referred to as a front end cross section) is sharp. The two planes adjacent to the tip are both planar.

In such a fixing device, as a means for promoting the separation of the transfer material from the fixing roller or the pressure roller after passing through the nip, a release agent is provided on at least one surface of the fixing roller and the pressure roller. An oil application mechanism for applying barrel oil is generally provided. For example, as a means of the oil application mechanism, a roller in which felt containing oil is formed in a roll shape, a roller in which felt is formed in a pad shape, or a web impregnated with oil is pressurized by a pressing roller, and periodically or continuously. Means for transporting the web in a practical manner have been put to practical use.

As means for cleaning the toner remaining on the fixing roller, separately from the oil application mechanism,
Alternatively, a cleaning mechanism having an oil application mechanism is used. As a means of the cleaning mechanism, as in the case of the oil application mechanism, a felt formed in a roll shape, a felt formed in a pad shape, or a web is pressed with a pressing roller to periodically or continuously press the web. Means for transporting have been put to practical use.

Further, in such a fixing device, a temperature detecting means such as a thermistor is disposed on or adjacent to at least one surface of the fixing roller and the pressing roller, and the temperature is detected by the temperature detecting means. Based on the temperature, the driving of the heating means is controlled such that the temperatures of the fixing roller and the pressure roller are maintained within a predetermined temperature range.

[0007]

However, in such a fixing device, since the separation claw is in contact with the fixing roller, foreign matters such as oil, toner, paper dust, etc. adhering to the fixing roller are transferred to the separation claw. Adhere to. This attached matter is often attached to the nip side surface of the separation claw. After a large amount of the foreign matter is accumulated on the separation claw, the adhesive force between the separation claw and the foreign matter is reduced by an increase in the amount of the foreign matter, and the foreign matter is transferred to the transfer material. Such dirt has a problem of image failure.

In such a fixing device, the smaller the radius of curvature of the cross section at the tip of the separation claw, the better the separation of the transfer material after passing through the nip from the fixing roller or the pressure roller. Oil, toner, paper dust and the like are often removed from the roller or the pressure roller, and the speed at which foreign matter adheres to the separation claw is increased. For this reason, the frequency of foreign matter adhering to the transfer material increases, and the frequency of occurrence of image defects increases.

Accordingly, the present invention improves the separability of a recording medium after passing through a nip with respect to a fixing member or a pressing member and prevents image defects due to foreign matters such as oil, toner, and paper dust adhering to a separating member. It is an object of the present invention to provide a fixing device that can be used and an image forming apparatus including the fixing device.

[0010]

SUMMARY OF THE INVENTION According to the present application, the above object is to provide a recording medium having an unfixed image, comprising a fixing member and a pressing member which rotate by pressing against each other, and heating means for heating the fixing member. A fixing device for fixing the unfixed image on the recording medium by nipping and conveying a medium in a nip formed by the fixing body and the pressing body, and heating and pressing the medium, wherein the fixing body and the pressing At least one peripheral surface of the body has a contact portion extending in the axial direction of the fixing body or the pressing body, and the recording medium after passing through the nip is brought into contact with the fixing body or the pressing body by contact with the fixing body or the pressing body. In a fixing device including a separation member that separates from the surface of the pressure member, the separation member has a radius of curvature of a cross section perpendicular to the axial direction of a contact portion with the fixing member or the pressure member, which is 100 μm or less. There is a convex on the surface facing the nip side Is achieved by the first invention of have been made.

According to the present application, the above object is also achieved by the second invention in the first invention, wherein the separation member has a convex shape in a convex shape.

Further, according to the present application, the above object is achieved in the first invention or the second invention, wherein the separation member has a cross section perpendicular to the axial direction of a contact portion with the fixing member or the pressure member. This is also achieved by the third invention in which the radius of curvature is 30 μm or less.

Further, according to the present application, the above object is achieved by any one of the first to third inventions, wherein the separating member comprises:
The present invention is also achieved by the fourth invention in which a plurality of convex portions are formed on the surface facing the nip side.

Further, according to the present application, the above object is to provide an image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, which is provided with a fixing device of the first invention. The invention is also achieved by the invention of (1).

Further, according to the present application, the above object is also achieved by the sixth invention in the fifth invention, wherein the separating member has a convex portion having a mountain shape.

Further, according to the present application, the above object is achieved according to the fifth or sixth aspect, wherein the separation member has a cross section perpendicular to the axial direction of a contact portion with the fixing member or the pressure member. This is also achieved by the seventh invention in which the radius of curvature is 30 μm or less.

According to the present application, the above object is achieved by any one of the fifth to seventh inventions, wherein the separating member is:
The present invention is also achieved by the eighth invention in which a plurality of convex portions are formed on the surface facing the nip side.

That is, in the first invention according to the present application, the separation member having a proper shape of the contact portion with the fixing member or the pressure member is used to fix the recording medium after passing through the nip to the fixing member or the pressing member. While being separated from the surface of the pressure member, dirt such as toner adhered to the surface of the fixing member or the pressure member is collected at the center of the convex portion of the separation member, and the dirt falls without collecting in a large amount on the separation member. Alternatively, it is transferred onto a recording medium.

Further, in the second invention according to the present application, the separation member having an appropriate shape of the contact portion with the fixing member or the pressing member is used to fix the recording medium after passing through the nip to the fixing member or the fixing member. While being separated from the surface of the pressure member, dirt such as toner adhered to the surface of the fixing member or the pressure member is collected at the center of the mountain-shaped convex portion of the separation member, and a large amount of the dirt accumulates on the separation member. Without dropping or transferring onto a recording medium.

Further, in the third invention according to the present application, the separation member, which has a further optimized shape of the contact portion with the fixing member or the pressure member, fixes the recording medium after passing through the nip. Separation from the surface of the fixing member or the pressing member while the dirt such as toner adhered to the surface of the fixing member or the pressing member is collected at the center of the convex portion of the separating member, and a large amount of the dirt accumulates on the separating member. Without dropping or transferring onto the recording medium.

According to the fourth aspect of the present invention, the separation member having a proper shape of the contact portion with the fixing member or the pressure member and the dispersion of the contact portion with the recording medium is provided in the nip. While separating the recording medium after passing from the surface of the fixing member or the pressing member, dirt such as toner adhered to the surface of the fixing member or the pressing member is dispersed and collected at the center of the plurality of convex portions of the separating member. ,
The dirt falls or transfers onto the recording medium without collecting in large amounts on the separating member.

Further, in the fifth invention according to the present application, the separation member having an appropriate shape of the contact portion with the fixing member or the pressure member is used to fix the recording medium after passing through the nip to the fixing member or the fixing member. While being separated from the surface of the pressure member, dirt such as toner adhered to the surface of the fixing member or the pressure member is collected at the center of the convex portion of the separation member, and the dirt falls without collecting in a large amount on the separation member. Alternatively, it is transferred onto a recording medium.

According to the sixth aspect of the present invention, the separation member having an appropriate shape of the contact portion with the fixing member or the pressure member is used for fixing the recording medium after passing through the nip to the fixing member or the fixing member. While being separated from the surface of the pressure member, dirt such as toner adhered to the surface of the fixing member or the pressure member is collected at the center of the mountain-shaped convex portion of the separation member, and a large amount of the dirt accumulates on the separation member. Without dropping or transferring onto a recording medium.

Further, in the seventh invention according to the present application, the separation member, which has a further optimized shape of the contact portion with the fixing member or the pressure member, fixes the recording medium after passing through the nip. Separation from the surface of the fixing member or the pressing member while the dirt such as toner adhered to the surface of the fixing member or the pressing member is collected at the center of the convex portion of the separating member, and a large amount of the dirt accumulates on the separating member. Without dropping or transferring onto the recording medium.

According to the eighth aspect of the present invention, the separation member having a suitable shape of the contact portion with the fixing member or the pressure member and the dispersion of the contact portion with the recording medium is provided in the nip. While separating the recording medium after passing from the surface of the fixing member or the pressing member, dirt such as toner adhered to the surface of the fixing member or the pressing member is dispersed and collected at the center of the plurality of convex portions of the separating member. ,
The dirt falls or transfers onto the recording medium without collecting in large amounts on the separating member.

[0026]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a sectional view showing a schematic structure of an electrophotographic copying machine as an example of an image forming apparatus according to the present embodiment.

In this copying machine, as shown in FIG. 1, a document is placed between a document table cover 1 and a platen glass 2, and the document is illuminated by a document illumination lamp 3. By using the reflection mirrors 4, 5, 6, the lens 7 and the reflection mirror 8, the light of the original illumination lamp 3 reflected on the original is projected onto the photosensitive body 9 so as to correspond to the original on the photosensitive body 9. An image is formed. That is, the photoreceptor 9 is charged in advance by the charger 10 and the surface thereof is exposed to light corresponding to the above-described document image, whereby an electrostatic latent image is formed on the photoreceptor 9. Is done. Then, the toner is adhered to the electrostatic latent image by using the developing device 11 to visualize the toner image as a toner image, and the toner image is transferred and charged to a transfer material P conveyed from the paper feeding deck 12. The image is transferred by the container 13. Further, the transfer material P to which the toner image has been transferred is conveyed to the fixing device 15 by the conveyance belt 14, the toner image is fixed on the transfer material P by the fixing device 15, and is output to the paper discharge tray 16.

Next, the fixing device 15 will be described in detail.

As shown in FIG. 2, the fixing device 15 includes a fixing roller 20 as a fixing member and a pressing roller 21 as a pressing member, which are pressed against each other and rotates. With the toner-carrying surface facing the fixing roller 20, the toner is nipped and conveyed by a nip formed by the fixing roller 20 and the pressure roller 21.

The fixing roller 20 is made of, for example, iron or an aluminum alloy as a base of the structure, that is, a metal core, and its surface is formed of an elastic layer such as silicone rubber or fluorine rubber, or a tetrafluoroethylene resin (PTFE) or a tetrafluoroethylene resin. Coated with a highly releasable layer of a fluororesin represented by ethylene-perfluorovinylether copolymer (PFA) alone or in combination.

Similarly, the pressure roller 21 is also formed by covering an elastic layer or a high release layer on a cored bar.

The fixing device 15 is a halogen heater (not shown) as a general heat source in a fixing device that melts toner by heat, and a temperature detecting means for detecting a surface temperature of the fixing roller 20. A heating thermistor 22 for controlling the heating of the halogen heater so that the surface temperature of the fixing roller 20 detected by the thermistor 22 becomes 100 ° C. to 200 ° C.

Further, the fixing device 15 is provided with a separating claw 23 as a separating member in order to prevent the transfer material after passing through the nip from winding around the fixing roller 20.

The fixing device 15 is formed of a non-woven cloth or the like as a releasing agent applying means in order to apply oil as a releasing agent to improve the releasing property of the fixing roller 20 and the pressing roller 21. A web 30 and a pressing roller 31 for bringing the web 30 into contact with the fixing roller 20 are provided. The web 30 and the like not only apply oil, but also apply an offset toner adhering to the fixing roller 20. It is also intended to clean.

The web 30 is wound around a feed roller 32 in advance, and is gradually wound around a winding roller 33. The winding drive method is obtained by, for example, switching a reciprocating motion from a solenoid or a rotary motion to a dedicated motor, or reducing the rotation of the fixing roller 20 by a gear. The winding timing is
In the case of a motor or a solenoid, the operation is performed every time an image is output, and when the rotation of the fixing roller 20 is reduced by a gear, the operation is performed continuously.

The oil application mechanism and the separation claw 2
Reference numeral 3 denotes a mechanism that can be attached to both the fixing roller 20 and the pressure roller 21.

Here, in order to clarify the difference between the fixing device according to the present invention and the conventional fixing device, first, referring to FIG. 5, the separation claw provided in the conventional fixing device when passing through the transfer material nip will be described. The behavior and the contamination of the separation claw due to the behavior will be described.

In the prior art, as shown in FIG. 5, a separating claw 23 is disposed in contact with the fixing roller 20. The section of the tip of the separation claw 23 has a radius of curvature of 70 μm. The transfer material P that has passed through the nip between the fixing roller 20 and the pressure roller 21 is separated from the separation claw 2 by the characteristics of the transfer material and the image.
3 in a state of contact or non-contact.

This is generally because thin paper is easy to contact,
This is because an image having a high image density is likely to come into contact with the tip.

Foreign matter adheres to the conventional separation claw 23 due to such contact of the image and contamination of the fixing roller 20. As a result, a large amount of foreign matter adheres to the surface viewed from the direction A shown in FIG. 5, and the foreign matter falls or adheres to the transfer material, resulting in an image defect.

On the other hand, the section of the tip of the separation claw 123 according to the present invention has a radius of curvature of 70 μm. The behavior of the transfer material at the time of passing through the nip is similar to that of the conventional example, and the transfer material passes with or without contacting the separation claw 123. Adhesion of foreign matter to the separation claw 123 also occurs in the same manner as in the related art. However, the surface of the separation claw 123 viewed from the direction B shown in FIG. . For this reason, the dirt collects at the T portion and falls before being attached in a large amount. This is because, when the foreign matter is concentrated on the apex T, the contact surface area is reduced, and the bonding strength is reduced.

Tables 1 and 2 show the adhesion of dirt on the separation claw and the occurrence of a defective image in the present embodiment and the conventional example as Comparative Example 1, and Table 1 shows the transfer after passing through the nip. Table 2 shows the case where the transfer material does not contact the separation claw, and Table 2 shows the case where the transfer material after passing through the nip contacts the separation claw. Table 1
In Table 2 and Table 2, ○ indicates that the adhesion of dirt could not be confirmed visually, Δ indicates that the adhesion could be confirmed but there was no problem with the image, and x indicates that an image defect occurred.

[0045]

[Table 1]

[0046]

[Table 2]

First, in the durability of the transfer material and the image which do not come into contact with the separation claw, as shown in Table 1, in Comparative Example 1, an image defect occurs at 1,000,000 sheets, whereas in this embodiment, 1
No defective image is generated even for 100,000 sheets. In Table 1, △
Indicates that foreign matter has adhered to the separation nail, but this does not affect the image and is not considered to be a problem.

Next, as shown in Table 2, in the durability of the transfer material contacting the separation claw and the image, as shown in Table 2, an image defect occurs in 300,000 sheets in Comparative Example 1, whereas in the present embodiment, 100,000 sheets are defective.
No defective image is generated even for 10,000 sheets.

Therefore, according to the present embodiment, the shape of the contact portion with the fixing roller 20 is optimized, and the separation member having a curvature radius of the tip section of 100 μm or less passes the transfer material after passing through the nip to the fixing roller. 20, dirt such as toner attached to the surface of the fixing roller 20 is collected at the center of the protrusion of the separation claw 123, and
Since the toner is dropped or transferred onto the transfer material without being accumulated on a large amount, the transfer material after passing through the nip with respect to the fixing roller 20 is improved while removing oil, toner, paper dust, etc. adhering to the separation claw 123. Image defects due to foreign matter can be prevented.

(Second Embodiment) Next, a second embodiment of the present invention will be described. The description of the same configuration as that of the first embodiment is omitted.

In this embodiment, the radius of curvature of the section of the tip of the separation claw is 30 μm.

Here, the separation claw according to the present embodiment and Table 3
A comparative experiment was performed with the separation nails according to Comparative Examples 1 and 2 shown in Table 4.

[0053]

[Table 3]

[0054]

[Table 4]

Tables 3 and 4 show the adhesion of dirt on the separation claw and the occurrence of a defective image in the present embodiment and the conventional example as Comparative Examples 1 and 2, and Table 3 shows the results after passing through the nip. Table 4 shows a case in which the transfer material after passing through the nip contacts the separation claw. still,
In Tables 3 and 4, ○ indicates that the adhesion of dirt could not be confirmed visually, △ indicates that the adhesion could be confirmed but there was no problem with the image, and × indicates that an image defect occurred. I have.

In Tables 3 and 4, Comparative Example 1 shows that the transfer material contact surface (the surface facing the nip side, the same applies hereinafter) of the separation claw was flat and the radius of curvature of the cross section at the tip was 70 μm.
Means that the contact surface of the separation claw is flat and the tip section has a radius of curvature of 30.
In the first embodiment, the contact surface of the separation claw has a chevron shape with a radius of curvature of 70 μm at the tip end section, and the second embodiment has a contact surface of the separation claw with a chevron shape with a tip end cross section. The radius of curvature is 30 μm.

First, when the transfer material after passing through the nip does not come into contact with the separation claw, as shown in Table 3, an image defect occurs on 1,000,000 sheets in Comparative Example 1 and on 500,000 sheets in Comparative Example 2. .
On the other hand, there is no problem in the first embodiment and the second embodiment.

Next, when the transfer material after passing through the nip comes into contact with the separation claw, as shown in Table 4, an image defect occurs on 300,000 sheets in Comparative Example 1 and 100,000 sheets in Comparative Example 2. I have. On the other hand, there is no problem in the first embodiment and the second embodiment.

Table 5 shows the result of comparing the difference in separation performance depending on the radius of curvature of the cross section of the tip of the separation claw with a certain type of OHP as the OHP jam rate.

[0060]

[Table 5]

As shown in Table 5, the smaller the radius of curvature of the section of the tip of the separation claw, the higher the separation property of the OHP sheet and the faster the adhesion speed of foreign matter to the separation claw. Could not employ such a small radius of curvature.

However, according to the present invention, a small radius of curvature of the cross section at the tip can be adopted without any problem.

Therefore, according to the present embodiment, the shape of the contact portion with the fixing roller 20 is further optimized, and the separation member having a curvature radius of the front end section of 30 μm or less removes the transfer material after passing through the nip. While being separated from the surface of the fixing roller 20, dirt such as toner adhered to the surface of the fixing roller 20 is collected at the center of the convex portion of the separating claw, and the dirt is dropped or the transfer material is not accumulated on the separating claw in a large amount. Because the transfer material moves upward, the oil adhering to the separation claw can be removed while further improving the separability of the transfer material after passing through the nip with respect to the fixing roller 20.
Image defects due to foreign matters such as toner and paper dust can be prevented.

(Third Embodiment) Next, a third embodiment of the present invention will be described. The description of the same configuration as that of the first embodiment is omitted.

In this embodiment, in addition to the configuration of the first embodiment or the second embodiment, furthermore, an image on the transfer material after passing through the nip is improved against a nail mark caused by contact with the separation nail. It is.

FIG. 4 shows the shape of the separation claw according to the present embodiment.
FIG. 4 is a view of the separation claw according to the present embodiment in the same direction as the direction A in FIG. 5 and the direction B in FIG. 3, and T2 and T3 indicate mountain-shaped peaks.

Tables 6 and 7 show the adhesion of dirt on the separation claw and the occurrence of a defective image in this embodiment and the conventional example as Comparative Examples 1 and 2, and Table 6 shows the results after passing through the nip. Table 7 shows the case where the transfer material after passing through the nip contacts the separation claw. or,
Table 8 shows the occurrence of nail trailing due to the contact of the image with the separation claw when the transfer material after passing through the nip contacts the separation claw. In Tables 6, 7 and 8, ○ indicates that dirt could not be visually observed, Δ indicates that the adhesion could be confirmed but there was no problem with the image, and x indicates that the image was defective. Indicates that an event has occurred.

[0068]

[Table 6]

[0069]

[Table 7]

[0070]

[Table 8]

According to Tables 6 and 7, the image defect and the separability are the same as those of the second embodiment. However, from the table of the degree of the separated nail marks shown in Table 8, more excellent results are obtained with respect to the nail marks. . This is because the contact pressure is dispersed due to the large number of contact points. In the conventional example in which the shape of the transfer material contact surface is a flat surface, the shape is more dispersed at this point,
It is considered that the large contact area results in a poor looking image, a large influence, and the results shown in the table.

Thus, according to the present embodiment, the separation member having a contact portion with the transfer material and an appropriate shape of the contact portion with the fixing roller 20 can be achieved, and the separation member having a tip section with a radius of curvature of 100 μm or less can be obtained. The transfer material after passing through the nip is separated from the surface of the fixing roller 20, and dirt such as toner adhered to the surface of the fixing roller 20 is dispersed and collected at the centers of the plurality of convex portions of the separation claw. Since the toner is dropped or transferred onto the transfer material without being accumulated on the nail in a large amount, the fixing roller 20
Image quality due to foreign matter such as oil, toner and paper powder adhering to the separation claw can be effectively prevented while improving the separation property of the transfer material after passing through the nip.

[0073]

As described above, according to the first invention of the present application, the separation member having a proper shape of the contact portion with the fixing member or the pressure member is used for recording after passing through the nip. While the medium is separated from the surface of the fixing member or the pressing member, dirt such as toner adhered to the surface of the fixing member or the pressing member is collected at the center of the convex portion of the separating member, and a large amount of the dirt is deposited on the separating member. Fall or transfer onto the recording medium without collecting in the
While improving the separability of the recording medium after passing through the nip with respect to the fixing body or the pressing body, it is possible to prevent image defects due to foreign substances such as oil, toner, and paper powder adhering to the separating member.

According to the second invention of the present application,
A separating member having an appropriate shape of the contact portion with the fixing body or the pressing body separates the recording medium after passing through the nip from the surface of the fixing body or the pressing body, and the surface of the fixing body or the pressing body. The dirt such as toner adhered to the collecting member is collected at the center of the mountain-shaped convex portion of the separating member, and the dirt drops or transfers to the recording medium without collecting in a large amount on the separating member. The image defect due to foreign matters such as oil, toner, and paper powder adhering to the separating member can be prevented while improving the separability of the recording medium after passing through the nip.

Further, according to the third aspect of the present invention, the separation member having a further optimized shape of the contact portion with the fixing member or the pressurizing member fixes the recording medium after passing through the nip to the fixing member. Or, while being separated from the surface of the pressing member, dirt such as toner adhered to the surface of the fixing member or the pressing member is collected at the center of the convex portion of the separating member, and the dirt does not collect in a large amount on the separating member. Since the recording medium is dropped or transferred onto the recording medium, image defects due to foreign matters such as oil, toner, and paper dust adhering to the separating member while further improving the separability of the recording medium after passing through the nip with respect to the fixing body or the pressure body. Can be prevented.

According to the fourth invention of the present application,
The separation member, which is designed to optimize the shape of the contact portion with the fixing member or the pressure member and the dispersion of the contact portion with the recording medium, separates the recording medium after passing through the nip from the surface of the fixing member or the pressure member. The dirt such as toner adhered to the surface of the fixing member or the pressure member is dispersed and collected at the center of the plurality of convex portions of the separating member, and the dirt is dropped or recorded on the recording medium without collecting in a large amount on the separating member. To improve the separability of the recording medium after passing through the nip with respect to the fixing member or the pressing member, and effectively prevent image defects due to foreign matters such as oil, toner, and paper powder adhering to the separating member. .

Further, according to the fifth aspect of the present invention, the separation member having an appropriate shape of the contact portion with the fixing member or the pressure member can fix the recording medium after passing through the nip to the fixing member or the pressing member. While being separated from the surface of the pressure member, dirt such as toner adhered to the surface of the fixing member or the pressure member is collected at the center of the convex portion of the separation member, and the dirt falls without collecting in large amounts on the separation member or Since the toner is transferred onto the recording medium, it is possible to improve the separability of the recording medium after passing through the nip with respect to the fixing member or the pressure member, and to prevent image defects due to foreign substances such as oil, toner, and paper powder adhering to the separating member. .

According to the sixth aspect of the present invention,
A separating member having an appropriate shape of the contact portion with the fixing body or the pressing body separates the recording medium after passing through the nip from the surface of the fixing body or the pressing body, and the surface of the fixing body or the pressing body. The dirt such as toner adhered to the collecting member is collected at the center of the mountain-shaped convex portion of the separating member, and the dirt drops or transfers to the recording medium without collecting in a large amount on the separating member. The image defect due to foreign matters such as oil, toner, and paper powder adhering to the separating member can be prevented while improving the separability of the recording medium after passing through the nip.

Further, according to the seventh aspect of the present invention, the separation member whose contact portion with the fixing member or the pressure member is further optimized can fix the recording medium after passing through the nip to the fixing member. Or, while being separated from the surface of the pressing member, dirt such as toner adhered to the surface of the fixing member or the pressing member is collected at the center of the convex portion of the separating member, and the dirt does not collect in a large amount on the separating member. Since the recording medium is dropped or transferred onto the recording medium, image defects due to foreign matters such as oil, toner, and paper dust adhering to the separating member while further improving the separability of the recording medium after passing through the nip with respect to the fixing body or the pressure body. Can be prevented.

According to the eighth invention of the present application,
The separation member, which is designed to optimize the shape of the contact portion with the fixing member or the pressure member and the dispersion of the contact portion with the recording medium, separates the recording medium after passing through the nip from the surface of the fixing member or the pressure member. Soil such as toner adhered to the surface of the fixing member or the pressure member is dispersed and collected at the center of the plurality of protrusions of the separation member, and the stain falls without being accumulated on the separation member in a large amount or falls on the recording medium. To improve the separability of the recording medium after passing through the nip with respect to the fixing member or the pressing member, and effectively prevent image defects due to foreign matters such as oil, toner, and paper powder adhering to the separating member. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a fixing device provided in the image forming apparatus of FIG.

FIG. 3 is a cross-sectional view illustrating a schematic configuration of a separation member provided in the fixing device of FIG. 2 and a view of the separation member viewed from a surface facing a nip side.

FIG. 4 is a view of a separation member provided in a fixing device according to a third embodiment of the present invention as viewed from a surface facing a nip side.

FIG. 5 is a cross-sectional view illustrating a schematic configuration of a separation member provided in a conventional fixing device, and a view of the separation member viewed from a surface facing a nip side.

[Explanation of symbols]

 15 Fixing Device 20 Fixing Roller (Fixing Body) 21 Pressure Roller (Pressing Body) 123 Separation Claw (Separation Member) P Transfer Material (Recording Medium)

Claims (8)

[Claims] An image forming apparatus comprising: a fixing member and a pressing member that rotate in pressure contact with each other; and a heating unit that heats the fixing member, and a recording medium that carries an unfixed image is formed by the fixing member and the pressing member. A fixing device for fixing the unfixed image to the recording medium by nipping and conveying the recording medium by heating and pressing the nip, wherein at least one of the fixing member and the pressing member has the peripheral surface of the fixing member or the pressing member; A fixing member having a contact portion extending in the axial direction of the pressure member and having a separating member for separating the recording medium after passing through the nip from the surface of the fixing member or the pressure member by contact with the fixing member or the pressure member; The separating member has a radius of curvature of a cross section perpendicular to the axial direction of the contact portion with the fixing member or the pressing member of 100 μm or less, and the separating member has a convex portion formed on a surface facing the nip side. A fixing device. 2. The fixing device according to claim 1, wherein the projection of the separation member has a mountain shape. 3. The fixing member according to claim 1, wherein the separating member has a radius of curvature of a cross section perpendicular to the axial direction of a contact portion with the fixing member or the pressing member of 30 μm or less. apparatus. 4. The fixing device according to claim 1, wherein the separation member has a plurality of convex portions formed on a surface facing the nip side. 5. An image forming apparatus for recording an image formed by a series of image forming processes on a recording medium,
An image forming apparatus comprising the fixing device according to claim 1. 6. The image forming apparatus according to claim 5, wherein the projection of the separation member has a mountain shape. 7. The image according to claim 5, wherein the separating member has a radius of curvature of a section perpendicular to the axial direction of a contact portion with the fixing member or the pressing member of 30 μm or less. Forming equipment. 8. The image forming apparatus according to claim 5, wherein the separation member has a plurality of protrusions formed on a surface facing the nip side.