JP2009103938A - Pressing member, method for manufacturing pressing member for fixing, fixing device, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressing member capable of preventing it from adhering to adjoining members, when a fixing device is used over a long term, thereby preventing the nip pressure distribution from changing, and reducing the occurrence of fixing failures, image quality unevenness, wrinkles on a recording material, or the like. <P>SOLUTION: The pressing member 64 for pressing a fixing belt 62 of the fixing device 60 is provided with a support plate 64b, on which through-holes are formed in the thickness direction, and a rubber layer 64a laminated on the surface of the support plate 64b, on which through-holes are formed, wherein the through-holes have diameters of 0.1-3 mm, and are formed within the range of 1-60% of the surface of the support plate 64b, where the rubber layer 64a is laminated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pressure member, and more particularly to a pressure member for fixing used in an electrophotographic copying machine or the like.

  2. Description of the Related Art Conventionally, image forming apparatuses such as electrophotographic copying machines and printers generally employ a thermal pressure fixing method in a fixing process for fixing a toner image formed on a recording medium onto the recording medium. . In such a heat-pressure fixing method, a non-fixed toner image is fixed on a recording material by heating and pressing at a nip formed by a fixing roll and a pressure roll with a built-in heater (so-called roll nip method). And a method (so-called belt nip method) in which a recording material is pressed against a fixing roll by a pressure pad from the inside of an endless belt used in place of a pressure roll to form a nip portion. Among them, the belt nip method is widely used as a thermal pressure fixing method with the progress of colorization, high speed, and miniaturization of image forming apparatuses.

With respect to such a belt nip method, Patent Document 1 provides a belt nip through which a sheet passes between an endless belt and a heat fixing roll, and locally elasticizes the sheet outlet side of the surface of the heat fixing roll. An image fixing device having a pressure pad to be deformed is described.
In Patent Document 2, a pressure member is attached to the heat fixing roller via the endless belt so that the nip pressure is increased near the exit of the nip portion in the nip portion formed between the endless belt and the heat fixing roller. A fixing device is described in which the heat-resistant elastic layer of the heat-fixing roller is distorted by being pressed.

Japanese Patent No. 3298354 JP 2001-356625 A

By the way, in the thermal pressure fixing method, for example, a fixing roll is pressed from the inside of the endless belt using a pressure member made of heat-resistant rubber having low hardness such as silicone rubber, and a nip portion N through which the recording material passes is formed. is doing.
However, when a pressure member made of silicone rubber is used for a long time under heating and high temperature (about 120 ° C. to 160 ° C.), various pressure substances such as adhesive substances considered to be uncrosslinked from the inside of the pressure member The compound may leach out to the surface (bleed phenomenon).
When such various compounds are leached to the surface, adhesion between the pressure member and the surrounding members occurs, and therefore, the nip pressure distribution changes, and there is a tendency for fixing failure, image quality unevenness, wrinkles of the recording material, etc. There is.

  The present invention has been made to solve the above-described problems. That is, an object of the present invention is to prevent adhesion with other adjacent members during long-time use, without changing the nip pressure distribution, and without causing improper fixing, uneven image quality, wrinkling of the recording material, etc. It is to provide a member.

  The invention according to claim 1 is a pressure member that presses the belt member of the fixing device, and has a support plate in which a through hole is formed in the thickness direction, and a surface of the support plate on which the through hole is formed. And a laminated rubber layer.

  The invention according to claim 2 is the pressure member according to claim 1, further comprising a fluororesin layer covering the surface of the rubber layer.

  The invention according to claim 3 is the pressurizing member according to claim 1, wherein the through hole of the support plate is filled with rubber constituting the rubber layer.

The invention according to claim 4 is characterized in that the rubber layer is formed by curing an addition reaction type silicone rubber composition containing the following components (A), (B) and (C). Item 2. The pressure member according to Item 1.
(A) Liquid organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by weight (B) Liquid organopolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule Hydrogen polysiloxane: 0.1 to 30 parts by weight (C) Addition reaction catalyst for reacting (A) and (B)

  According to a fifth aspect of the present invention, the through hole has a diameter of 0.1 mm to 3 mm and is formed within a range of 1% to 60% of the surface of the support plate on which the rubber layer is laminated. The pressure member according to claim 1, wherein the pressure member is a pressure member.

  The invention according to claim 6 is a method of manufacturing a fixing pressure member covered with a fluororesin tube, and a mold having an inner peripheral length of 1.01 to 1.2 times the inner diameter of the fluororesin tube. The fluororesin tube is disposed in the mold, the addition reaction type silicone rubber composition is injected inside the fluororesin tube disposed in the mold, and the addition reaction type silicone rubber composition is injected inside the fluororesin tube. This is a method for producing a fixing pressure member characterized by curing an object.

  According to a seventh aspect of the present invention, there is provided a rotating member that is rotationally driven, a belt member that rotates opposite to the rotating member, and a support plate that is disposed inside the belt member and has a through-hole formed in a thickness direction. And a pressure member composed of a silicone rubber layer laminated on the support plate, wherein the pressure member presses the belt member against the rotating member. is there.

  According to an eighth aspect of the present invention, a toner image forming unit that forms a toner image, a transfer unit that transfers the toner image onto a recording material, and a toner image that is transferred onto the recording material are fixed on the recording material. A fixing unit, and the fixing unit rotates to rotate and faces the rotating member, and forms a nip portion through which the recording material passes between the rotating member and the fixing member. A pressure member having a belt member, a support plate disposed inside the belt member and having a through-hole formed in a thickness direction, and a silicone rubber layer laminated on the support plate, and the pressure member An image forming apparatus comprising: a peeling member disposed adjacent to the pressure member via a heat resistant resin film provided between the belt member and disposed in an exit region of the nip portion inside the belt member. It is.

According to the first aspect of the present invention, the bleed resistance of the pressure member is increased compared to the case where the support plate having the through holes formed in the thickness direction is not provided, and fixing failure of the fixing device is prevented. Reduces wrinkling of the material.
According to the invention which concerns on Claim 2, the bleed resistance of a pressurization member further improves compared with the case where it does not have a fluororesin layer.
According to the invention which concerns on Claim 3, compared with the case where a rubber layer is not filled in a through-hole, the adhesiveness of a rubber layer and an indicator plate improves.
According to the invention which concerns on Claim 4, compared with the case where liquid silicone rubber is not used, heat resistance, workability, and compression distortion resistance improve.
According to the invention which concerns on Claim 5, compared with the case where it does not have this structure, durability improves and the effect of bleeding resistance is remarkable.
According to the sixth aspect of the invention, a uniform fluororesin layer is formed on the rubber layer surface by setting the inner peripheral length of the mold to 1.01 to 1.2 times the inner diameter of the fluororesin tube. .
According to the seventh aspect of the present invention, in comparison with a case where a pressure member having a support plate in which a through hole is formed in the thickness direction is not used, fixing failure is prevented and wrinkling of the recording material is reduced.
According to the eighth aspect of the present invention, as compared with the case where this configuration is not provided, adhesion between the peeling member and the pressure member is prevented, fixing failure is prevented, and wrinkling of the recording material is reduced.

  Embodiments of the present invention will be described below. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary. Also, the drawings used are used to describe the present embodiment and do not represent the actual size.

  FIG. 1 is a schematic configuration diagram of an image forming apparatus to which the exemplary embodiment is applied. Here, an intermediate transfer type image forming apparatus generally called a tandem type will be described as an example. The image forming apparatus shown in FIG. 1 includes a plurality of image forming units 1Y, 1M, 1C, and 1K that form toner images of respective color components by electrophotography as a toner image forming unit. Next, as the transfer unit, the primary transfer unit 10 that sequentially transfers (primary transfer) the color component toner images formed by the image forming units 1Y, 1M, 1C, and 1K to the intermediate transfer belt 15, and the intermediate transfer belt 15. A secondary transfer unit 20 that collectively transfers (secondary transfer) the transferred superimposed toner image onto a sheet P that is a recording material (recording sheet). Further, the image forming apparatus includes a fixing device 60 that fixes the secondary transferred image on the paper P as a fixing unit. Moreover, it has the control part 40 which controls operation | movement of each apparatus (each part).

  As shown in FIG. 1, each of the image forming units 1Y, 1M, 1C, and 1K includes a photosensitive drum 11 that rotates in the direction of arrow A, a charger 12, and a laser exposure device 13 (in FIG. 1, reference is made to an exposure beam). Bm) and a developing device 14. Further, it includes a primary transfer roll 16 and a drum cleaner 17. In the present embodiment, these image forming units 1Y, 1M, 1C, and 1K are arranged in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15. Arrange substantially linearly.

  The intermediate transfer belt 15 is circulated and driven (rotated) at a predetermined speed in the direction of arrow B shown in FIG. 1 by various rolls. As various rolls, a drive roll 31, a support roll 32, a tension roll 33, a backup roll 25, and a cleaning backup roll 34 are provided.

  The primary transfer unit 10 includes a primary transfer roll 16 that faces the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. A voltage (primary transfer bias) having a polarity opposite to the charging polarity (minus polarity) of the toner is applied to the primary transfer roll 16, and the toner images on the photosensitive drums 11 are sequentially electrostatically attracted to the intermediate transfer belt 15, A superimposed toner image is formed on the transfer belt 15.

The secondary transfer unit 20 includes a secondary transfer roll 22 disposed on the toner image holding surface side of the intermediate transfer belt 15 and a backup roll 25. A backup roll 25 is disposed on the back side of the intermediate transfer belt 15 to serve as a counter electrode of the secondary transfer roll 22, and a metal power supply roll 26 to which a secondary transfer bias is stably applied is disposed in contact.
The secondary transfer roll 22 is placed in pressure contact with the backup roll 25 with the intermediate transfer belt 15 interposed therebetween, and further, the secondary transfer roll 22 is grounded to form a secondary transfer bias between the secondary transfer roll 22 and the secondary transfer section. The toner image is secondarily transferred onto the paper P transported to the paper 20.

  An intermediate transfer belt cleaner 35 is provided on the downstream side of the secondary transfer portion 20 of the intermediate transfer belt 15 so as to be able to contact and separate. A reference sensor (home position sensor) 42 is disposed upstream of the yellow image forming unit 1Y. Further, an image density sensor 43 is disposed on the downstream side of the black image forming unit 1K. The reference sensor 42 recognizes a predetermined mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. In response to an instruction from the control unit 40 based on the recognition of the reference signal, each image forming unit 1Y, 1M, 1C and 1K start image formation.

  In the present embodiment, as a paper transport system, a paper tray 50 that stores paper P, a pickup roll 51 that takes out and transports the paper P in the paper tray 50, a transport roll 52 that transports the paper P, and a paper P A transport chute 53 that transports the paper P to the secondary transfer unit 20, a transport belt 55 that transports the paper P secondarily transferred by the secondary transfer roll 22 to the fixing device 60, and a fixing inlet that guides the paper P to the fixing device 60. And a guide 56.

Next, a basic image forming process of the image forming apparatus will be described.
In the image forming apparatus shown in FIG. 1, an image processing apparatus (IPS) (FIG. 1) is added to image data output from an image reading apparatus (IIT) (not shown), a personal computer (PC) (not shown), or the like. The image forming operation is executed by the image forming units 1Y, 1M, 1C, and 1K. The IPS performs predetermined image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, moving editing, and other various image editing on the input reflectance data. The image data subjected to the image processing is converted into color material gradation data of four colors Y, M, C, and K, and is output to the laser exposure unit 13.

  The laser exposure unit 13 irradiates the photosensitive drum 11 of each of the image forming units 1Y, 1M, 1C, and 1K with an exposure beam Bm according to the input color material gradation data. After the surfaces of the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K are charged by the charger 12, the surfaces are scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent image is developed as a toner image of each color of Y, M, C, and K by each of the image forming units 1Y, 1M, 1C, and 1K.

  Next, the toner image formed on the photosensitive drum 11 is transferred onto the intermediate transfer belt 15. Specifically, in the primary transfer unit 10, a voltage (primary transfer bias) having a polarity opposite to the charging polarity (minus polarity) of toner is applied to the base material of the intermediate transfer belt 15 by the primary transfer roll 16, The image is sequentially superimposed on the surface of the intermediate transfer belt 15 to perform primary transfer.

  After the toner image is sequentially primary-transferred onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves to convey the toner image to the secondary transfer unit 20. The paper transport system rotates the pickup roll 51 in accordance with the timing at which the toner image is transported to the secondary transfer unit 20, and supplies paper P of a predetermined size from the paper tray 50. The paper P supplied by the pickup roll 51 is transported by the transport roll 52 and reaches the secondary transfer unit 20 via the transport chute 53. Before reaching the secondary transfer unit 20, the paper P is temporarily stopped, and a registration roll (not shown) is rotated in accordance with the movement timing of the intermediate transfer belt 15 holding the toner image. Alignment with the position of the toner image is performed.

  In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the backup roll 25 via the intermediate transfer belt 15. At this time, the paper P is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At this time, a voltage (secondary transfer bias) having the same polarity as the toner charging polarity (minus polarity) is applied from the power supply roll 26, and a transfer electric field is formed between the secondary transfer roll 22 and the backup roll 25. Then, the unfixed toner image held on the intermediate transfer belt 15 is pressed at the secondary transfer unit 20 by the secondary transfer roll 22 and the backup roll 25, and electrostatically transferred onto the paper P at once.

Thereafter, the sheet P on which the toner image has been electrostatically transferred is peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22 and conveyed as it is, and is conveyed to a conveyance belt 55 provided on the downstream side of the secondary transfer roll 22 in the sheet conveyance direction. To do. The conveyance belt 55 conveys the paper P to the fixing device 60. The fixing device 60 processes the unfixed toner image on the paper P with heat and pressure and fixes it on the paper P. The paper P on which the fixed image is formed is conveyed to a paper discharge placement unit provided in the discharge unit of the image forming apparatus.
On the other hand, after the transfer to the paper P is completed, the residual toner remaining on the intermediate transfer belt 15 is conveyed to the cleaning unit as the intermediate transfer belt 15 rotates, and the cleaning backup roll 34 and the intermediate transfer belt cleaner 35 are transferred. To remove from the intermediate transfer belt 15.

(Fixing device 60)
Next, the fixing device 60 used in the image forming apparatus of the present embodiment will be described.
FIG. 2 is a side cross-sectional view illustrating the configuration of the fixing device 60 to which the present exemplary embodiment is applied. The fixing device 60 is disposed inside a fixing roll 61 as an example of a rotating member, a fixing belt 62 as a belt member that rotates by being pressed against the fixing roll 61, and the fixing belt 62. A main part is configured by a pressure member 64 that is pressed against 61 and a peeling member 64 c that is disposed in the exit region of the nip portion N inside the fixing belt 62.
The pressure member 64 includes a support plate 64b and a rubber layer 64a laminated on the support plate 64b, and a plurality of through holes are formed in the thickness direction of the support plate 64b (not shown). In the present embodiment, the rubber layer 64a is composed of a silicone rubber layer. The pressure member 64 will be described later.
A gap 65a is provided near the center of the portion of the holder 65 that supports the pressing member 64 that contacts the support plate 64b.
Further, a heat resistant resin film 64d is disposed between the pressure member 64 and the peeling member 64c in order to prevent the pressure member 64 and the peeling member 64c from being bonded.

A fixing roll 61 as a rotating member is formed by laminating an elastic layer 612 made of silicone rubber or the like and a release layer 613 made of fluorine resin or the like around a metal cylindrical cored bar 611 made of iron, aluminum, or the like. A cylindrical roll having a layer structure. The elastic layer 612 usually has a rubber hardness of 15 to 45 degrees (JIS-A) and a thickness of 0.1 mm to 1.5 mm. The release layer 613 is usually formed by melting and extruding a slightly smaller diameter fluororesin tube than the fixing roll 61 and covering the fixing roll 61 with an expansion rate of 1% to 5%.
The fixing roll 61 is rotatably supported and rotates at a predetermined surface speed (for example, 194 mm / sec). The fixing roll 61 of the present embodiment is formed of a straight roll having an outer diameter that is uniform in the axial direction.
Inside the fixing roll 61, for example, a halogen heater 66 having a rating of 600 W is disposed as a heat source. On the other hand, a temperature sensor 69 is disposed in contact with the surface of the fixing roll 61. The control unit 40 (see FIG. 1) of the image forming apparatus controls the lighting of the halogen heater 66 based on the temperature measurement value by the temperature sensor 69, and the surface temperature of the fixing roll 61 is a predetermined set temperature (for example, 175 ° C.). ) Is maintained.

The fixing belt 62 as a belt member is a seamless endless belt formed in a cylindrical shape. The fixing belt 62 includes a base layer and a surface layer formed on the surface or both surfaces of the base layer on the fixing roll 61 side. For the base layer, for example, a heat resistant resin such as polyimide, polyamideimide, or polybenzimidazole resin is used. For the surface layer, a fluororesin such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) or polytetrafluoroethylene (PTFE) is used.
The fixing belt 62 includes a pressure member 64 disposed inside the fixing belt 62, a peeling member 64c and a belt guide member 63, and edge guide members (not shown) disposed at both ends of the fixing belt 62. , And is supported rotatably. And it arrange | positions so that the paper P which is a recording material may press-contact with the fixing roll 61, and it may arrange | position and it follows the fixing roll 61 and rotates (for example, 194 mm / sec).

  Note that the paper P that has passed through the nip N is peeled off from the fixing belt 62 due to a change in the curvature of the fixing belt 62 in the exit region (peeling nip) of the nip N. Further, a peeling assisting member 70 is disposed on the downstream side of the nip portion N of the fixing belt 62 as a peeling assisting means. The peeling assisting member 70 is held by a baffle holder 72 in a state where the peeling baffle 71 is close to the fixing belt 62 in a direction (counter direction) opposite to the rotation direction of the fixing belt 62.

Further, a low friction sheet 68 is disposed between the pressure member 64 and the fixing belt 62 to reduce sliding resistance between the inner peripheral surface of the fixing belt 62 and the pressure member 64. In the present embodiment, both ends of the low friction sheet 68 are fixed to the holder 65.
Further, a lubricant application member 67 is disposed in the holder 65 over the longitudinal direction of the fixing device 60. The lubricant applying member 67 contacts the inner peripheral surface of the fixing belt 62 and supplies the lubricant to the sliding portion between the fixing belt 62 and the low friction sheet 68.

As shown in FIG. 2, in the present embodiment, a nip portion N adjacent to the pressure member 64 via the heat resistant resin film 64 d provided between the pressure member 64 and the inner side of the fixing belt 62. The peeling member 64c is arranged in the exit region.
The peeling member 64c is made of a metal such as iron, aluminum, or SUS. The shape of the peeling member 64c is a convex curved surface having an outer surface shape at the nip portion N having a constant radius of curvature. Note that the peeling member 64c may be formed using a heat-resistant resin such as PPS, polyimide, polyester, or polyamide.

  The heat resistant resin film 64d is disposed in order to prevent the pressure member 64 and the peeling member 64c from coming into close contact with each other, and to reduce fluctuations in the nip pressure due to the adhesion between the pressure member 64 and the peeling member 64c. Examples of the material constituting the heat resistant resin film 64d include fluororesins such as a tetrafluoroethylene polymer, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, and a tetrafluoroethylene / hexafluoropropylene copolymer. The thickness of the heat resistant resin film 64d is usually 10 μm to 500 μm. When the thickness of the heat resistant resin film 64d is excessively small, the mechanical strength of the film tends to be lowered. On the other hand, if the thickness is excessively large, the rigidity of the film itself is increased and the pressure balance of the nip portion N tends to be affected.

  In addition, heat resistant powder may be dispersed and adsorbed on the surface of the heat resistant resin film 64d. Examples of such heat-resistant powder include tetrafluoroethylene polymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, Fluororesin powders such as vinylidene fluoride polymer and chlorotrifluoroethylene polymer; fluorocarbon and the like.

(Pressure member 64)
Next, the pressure member 64 will be described.
In the present embodiment, a pressure member 64 that is disposed inside the fixing belt 62 and presses the fixing belt 62 against the fixing roll 61 includes a support plate 64b in which a through hole is formed in the thickness direction, and a penetration of the support plate 64b. And a rubber layer 64a laminated on the surface where the holes are formed.

(Support plate 64b)
Examples of the material constituting the support plate 64b include heat-resistant resins such as polyphenylene sulfide (PPS), polyimide, polyester, and polyamide; metals such as iron, aluminum, and SUS. The support plate 64b has a flat plate shape, and its thickness is usually 0.1 to 2 mm in view of the moldability and cost of the support plate 64b.

FIG. 3 is a diagram illustrating the through hole of the support plate 64b. As described above, through holes are formed in the thickness direction in the support plate 64b so as to penetrate the back surface from the front surface. Figure 3 (a) - (1) is a plan view of the support plate 64b ₁ of circular through-holes _{h 1} is formed, FIG. 3 (a) - (2), as shown in FIG. 3 (a) - ( It is xx 'sectional drawing of 1). 3 (b)-(1) is a plan view of the support plate 64b ₂ in which a square through hole h ₂ is formed, and FIGS. 3 (b)-(2) are FIGS. 3 (b)-( It is yy 'sectional drawing of 1).

By forming the through hole in the thickness direction, an adhesive substance or the like that oozes out from the pressure member 64 (see FIG. 2) laminated on the support plate 64b bleeds in the through hole direction. For this reason, even if the pressure member 64 is subjected to a temperature change or nip pressure load at a high temperature, adhesion to the adjacent peeling member 64c (see FIG. 2) is prevented. As a result, the nip pressure distribution does not change for a long period of time, and the occurrence of poor fixing, uneven image quality, wrinkles of the recording material, etc. is greatly reduced.
In the present embodiment, as shown in FIG. 2 described above, a gap 65a is provided near the center of the portion of the holder 65 that supports the pressing member 64 that is in contact with the support plate 64b (see FIG. 2). . By providing the gap 65a in the vicinity of the center of the holder 65, bleeding of the adhesive substance or the like that oozes out from the pressing member 64 in the direction of the through hole is promoted. Note that the gap 65a does not have to be formed in the portion of the holder 65 that contacts the support plate 64b.

As shown in FIG. 3 (a), the diameter phi ₁ of the circular through-hole _{h 1} penetrating in the thickness _{L 1} direction of the support plate 64b ₁ is usually in the range of 0.1 mm to 3 mm. If the diameter phi ₁ of the through hole h ₁ is excessively small, sticky substance such as oozing from the pressure member 64 there is a tendency that it is difficult to bleed through the through-hole h _1. If the diameter phi ₁ of the through hole h ₁ is excessively large, for example, by long-term use of the above 240 hours, it occurs depressurization injury to the part of the through hole h _1, fixing failure, uneven image quality, such as wrinkling of the recording material occurs Tend.

Further, as shown in FIG. 3 (b), the length _{d 2} of one side of the through-hole _{h 2} square penetrating in the thickness _{L 2} direction of the support plate 64b ₂ is generally in the range of 0.1mm~3mm is there. When the length d ₂ of one side of the square through hole h ₂ is excessively small, sticky substances tends to be difficult to bleed through the through-hole h _2. When one side of the length d ₂ of the through hole h ₂ is excessively large, the long-term use, there is a pressure release injury occurs tendency in the portion of the through hole h _2.

  The shape of the through hole is not limited to a circle or a square as described above, and can be variously selected as necessary. Here, when the shape of the through hole is other than a circle, the diameter of the through hole is a diameter when a maximum circle inscribed in the through hole is drawn. For example, when the shape of the through hole is a rectangle of 1 mm × 4 mm, the diameter is 1 mm.

As shown in FIG. 3, the through holes h ₁ and h ₂ are uniformly formed on the respective surfaces of the support plates 64b ₁ and 64b ₂ without being biased. If the through holes h ₁ and h ₂ formed on the surface in contact with the pressing member 64 are unevenly distributed, the nip pressure distribution becomes non-uniform and wrinkles or the like are likely to occur in the recording material in the initial state, which is not preferable.
At this time, the area ratio of the through holes h ₁ and h ₂ formed on the respective surfaces of the support plates 64b ₁ and 64b ₂ is usually in the range of 1% to 60%. When the area ratio of the through holes h ₁ and h ₂ is excessively small, the effect of providing the through holes h ₁ and h ₂ is reduced. When the area ratio is excessively large, the pressure loss of the through holes h ₁ and h ₂ is remarkable. Tend to be.

(Rubber layer 64a)
Next, the rubber layer 64a laminated | stacked on the surface in which the through-hole of the support plate 64b was formed is demonstrated. The rubber layer 64a is composed of an elastic body made of heat resistant rubber. In the present embodiment, silicone rubber is used as the heat resistant rubber. In the present embodiment, the durometer hardness of the rubber layer 64a is usually in the range of A5 to A30 (unit: °), preferably A10 to A20 (unit: °). Here, the durometer hardness is standardized as durometer type A (Shore A) in JISK6253. If the durometer hardness of the rubber layer 64a is excessively large, the toner cannot be sufficiently wrapped during fixing, and the image tends to be distorted.

  In the present embodiment, the rubber layer 64a is preferably obtained by curing an addition reaction type silicone rubber composition containing the following components (A), (B) and (C). Such an addition reaction type silicone rubber composition includes, as a main component, (A) liquid organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by weight, and (B) in one molecule. A liquid organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms is used in an amount of 0.1 to 30 parts by weight, and these (A) and (B) are reacted (C) And an addition reaction catalyst.

Examples of the alkenyl group of the liquid organopolysiloxane (A) include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group, and an octenyl group. Among these, a vinyl group is preferable.
Moreover, the liquid organopolysiloxane which is (A) component may have substituents other than the alkenyl group mentioned above. Examples of the substituent other than the alkenyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, and an octyl group. Group, nonyl group, alkyl group such as decyl group; aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group; chloromethyl group, chloropropyl group , A bromoethyl group, a trifluoropropyl group, a cyanoethyl group or the like in which a part or all of the hydrogen atoms are substituted with a halogen atom, a cyano group or the like.

The structure of the liquid organopolysiloxane which is the component (A) preferably has a linear structure, but may partially have a branched structure, a cyclic structure, or the like.
Further, the molecular weight of the liquid organopolysiloxane which is the component (A) is not particularly limited, and the viscosity at 25 ° C. is usually 500,000 mPa · S or less. If the molecular weight of the liquid organopolysiloxane is excessively large, the processability tends to decrease.

Examples of the liquid organohydrogenpolysiloxane as component (B) include trimethylsiloxy group-blocked methylhydrogen polysiloxane at both ends, trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, and dimethylhydro at both ends. Gensiloxy group-blocked dimethylsiloxane, both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer, both ends trimethylsiloxy group-blocked methyl hydrogen diphenylsiloxane-dimethylsiloxane _copolymer, a copolymer consisting of _(CH 3) 2 _{HSiO 1/2} units and _{SiO 4/2} units Include a copolymer consisting of _{(CH 3)} 2 _{HSiO 1/2} units and _{SiO 4/2} units and _{(C 6 H 5) 3 SiO} 3/2 units.

  In addition, the molecular weight of the liquid organohydrogenpolysiloxane as the component (B) is not particularly limited, and the viscosity at 25 ° C. is usually 1,000 mPa · S or less. If the molecular weight of the liquid organohydrogenpolysiloxane is excessively large, the processability tends to decrease.

  The addition reaction type silicone rubber is usually subjected to an addition reaction between (A) liquid organopolysiloxane and (B) liquid organohydrogenpolysiloxane in the presence of (C) an addition reaction catalyst. (C) As an addition reaction catalyst, for example, platinum black, platinous chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid and olefins, platinum bisacetoacetate, etc. Platinum group metal catalysts such as platinum catalysts, palladium catalysts, rhodium catalysts, and the like.

  In addition, in this Embodiment, another component can be mix | blended with the composition containing (A) component, (B) component, and (C) component mentioned above as needed. Examples of such other components include reinforcing silica fillers such as silica hydrogel (hydrous silicic acid), silica airgel (anhydrous silicic acid-fumed silica), and surface-treated fumed silica; clay, calcium carbonate, titanium dioxide And the like; heat resistance improvers such as iron oxide, cerium oxide, and iron octylate; various carbon functional silanes, nitrogen compounds, halogen compounds, and the like.

(Fluorine resin layer)
In the present embodiment, it is preferable to further include a fluororesin layer that covers the surface of rubber layer 64a (not shown). By forming a fluororesin layer on the surface of the rubber layer 64a, for example, the rubber layer 64a swells and is deformed by a lubricant such as silicone oil applied to the inner surface of the fixing belt 62 (see FIG. 2). Can be prevented from decreasing.
The thickness of the fluororesin layer is usually in the range of 5 μm to 50 μm. When the thickness of the fluororesin layer is excessively thin, unevenness occurs in the fluororesin layer and it tends to swell with the lubricant. On the other hand, if the thickness is excessively thick, the hardness of the entire rubber layer 64a tends to increase.
The method of forming the fluororesin layer is not particularly limited. For example, a method of coating a fluororesin latex coating agent (for example, Daiel Latex GLS-213F manufactured by Daikin Industries, Ltd.) by spraying or the like, There is a method of coating a tube formed by extrusion molding. Among these, a method of covering the fluororesin tube is preferable.
If the surface of the rubber layer 64a is covered with a fluororesin tube using a fluororesin tube, the pressurizing member 64 may cause poor fixing, uneven image quality, wrinkling of the recording material, etc. when used for a long time of 720 hours or longer. Absent.

  Examples of the fluororesin tube include polytetrafluoroethylene resin (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA), fluorinated ethylene-propylene copolymer resin (FEP), and polyvinylidene fluoride resin. (PVDF), polyvinyl fluoride resin tubes, etc. are mentioned. Among these, those using PFA tubes are particularly preferable.

  Furthermore, in the present embodiment, it is preferable that a plurality of through holes formed in the support plate 64b are filled with silicone rubber constituting the rubber layer 64a. Filling the through hole with silicone rubber increases the contact area between the support plate 64b and the rubber layer 64a, and improves the adhesion between the support plate 64b and the rubber layer 64a.

  The method of coating the surface of the rubber layer 64a with a fluororesin layer, and the method of molding the pressure member 64 by filling the plurality of through holes formed in the support plate 64b with silicone rubber are particularly limited. There are known methods. For example, a method of injecting an addition reaction type silicone rubber composition inside a fluororesin tube placed in a mold and then curing the addition reaction type silicone rubber composition can be mentioned.

Specifically, the following operations are mentioned.
For example, FIG. 4 is a diagram illustrating a mold for molding the pressing member 64 to which the present embodiment is applied. FIG. 4A is a plan view showing the lower mold. FIG. 4B is a view showing a fluororesin tube in which a support plate having a length W in the longitudinal direction is disposed. FIG. 4C is a plan view showing the upper mold.

As shown in FIG. 4A, the lower mold is formed with a recess having the same dimension as the length W in the longitudinal direction of the support plate so that the support plate can be fitted. As shown in FIG. 4C, a groove having a depth of 5 mm is formed in the upper mold. At this time, the inner peripheral length of the mold is preferably 1.01 to 1.2 times the inner diameter of the fluororesin tube. When the inner peripheral length of the mold is within this range, a pressure member having high quality stability and durability can be obtained. In addition, a fixing device including such a pressure member is less likely to cause poor fixing, uneven image quality, wrinkling of a recording material, and the like.
If the inner peripheral length of the mold is excessively small, the fluororesin tube tends to be molded while being broken. In addition, when the inner peripheral length of the mold is excessively large, the fluororesin tube tends to be permanently deformed and a wave is likely to occur.

The support plate is made of, for example, SUS and has a width of 8 mm and a thickness of 1 mm. Prior to molding, the surface of the support plate is washed in advance with toluene, a silicone rubber adhesion primer (No. 101 manufactured by Shin-Etsu Chemical Co., Ltd.) is applied, and air drying is performed for about 30 minutes.
As the fluororesin tube, a PFA tube (P-66P manufactured by Asahi Glass Co., Ltd.) having a diameter of 7 mm to 10 mm and a thickness of about 30 μm and having an inner surface treated for adhesion is used.

  First, as shown in FIG. 4B, a support plate (however, through holes are not shown) is disposed on the inner surface of the fluororesin tube, and the lower mold shown in FIG. The support plate is inserted into the recess having the same dimensions as the support plate through the PFA tube. Next, the upper mold and the lower mold shown in FIG. 4C are overlapped and fixed so as not to sandwich the PFA tube. Subsequently, both end portions of the PFA tube protruding from the mold are sandwiched. Next, a jig for injecting the addition reaction type silicone rubber composition is prepared at one end, and a hole for slightly venting air is prepared at the other end.

  Subsequently, the addition reaction type silicone rubber composition is injected from a jig prepared at one end, and then the jig is taken out and usually subjected to a baking treatment at 140 ° C. for about 1 hour. After firing, the portion of the PFA tube that protrudes from both ends of the support plate is cut out, and further, secondary vulcanization is usually performed at about 200 ° C. for about 4 hours to form a pressure member. As the addition reaction type silicone rubber composition, for example, one having a hardness of 18 ° according to JIS-A standard (KE1340 manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples. In addition, this invention is not limited to a following example, unless the summary is exceeded.
(Examples 1-3, Comparative Examples 1 and 2)
(Evaluation of initial paper wrinkle characteristics)
Using the mold shown in FIG. 4, a pressure member in which the surface of the rubber layer was coated with a fluororesin layer was molded in the range shown in Table 1 (inner perimeter of mold / inner diameter of fluororesin tube). Then, using the image forming apparatus (Fuji Xerox Co., Ltd. color printer DocuCenter Color 400) in which these pressure members are mounted on the fixing device 60 shown in FIG. We evaluated the occurrence of wrinkles. The pressure member is formed as follows.

A primer for silicone rubber adhesion (No. 101 manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to a SUS support plate (width 8 mm, thickness 1 mm) whose surface has been washed with toluene, and air-dried for 30 minutes. As the fluororesin tube, a PFA tube (P-66P manufactured by Asahi Glass Co., Ltd.) having a thickness of 30 μm, having an inner diameter shown in Table 1, and having an inner surface treated for adhesion is used.
Next, a support plate is fitted into the recess of the lower mold (FIG. 4 (a)) via a PFA tube, and the upper mold (FIG. 4 (c)) is overlaid and fixed, and an addition reaction type silicone rubber composition ( KE1340 manufactured by Shin-Etsu Chemical Co., Ltd .: JIS-A standard hardness 18 °), and after calcination treatment at 140 ° C. × 1 hour, secondary vulcanization is further performed under the conditions of 200 ° C. × 4 hours, and a pressure member Is molded.
The occurrence of paper wrinkles on the recording material was evaluated according to the following criteria. The results are shown in Table 1.
Initial paper wrinkle characterization:
A: Paper wrinkles do not occur when five sheets are continuously fed.
B: Paper wrinkles occurred on one sheet after five sheets were continuously passed.
C: Paper wrinkles were generated on 2 or more sheets after 5 continuous sheets were passed.

From the results shown in Table 1, a pressure member coated with a fluororesin tube was molded using a mold having an inner peripheral length of 1.05 to 1.19 times the inner diameter of the fluororesin tube (Example) 1-3) It can be seen that in an image forming apparatus provided with a fixing device equipped with this, paper wrinkles do not occur when five recording materials are continuously fed.
On the other hand, molding is performed using a mold having an inner peripheral length of 0.99 times and 1.27 times the inner diameter of the fluororesin tube (Comparative Examples 1 and 2), and an image is formed with a fixing device equipped with the mold. In the apparatus, it can be seen that paper wrinkles occur when five recording materials are continuously fed.

(Examples 4 and 5)
(Aging paper wrinkle characteristics evaluation)
Using the same support plate and silicone rubber as in Example 1 and using a pressure member formed by the following operation, the state of occurrence of paper wrinkles (evaluation of paper wrinkle characteristics over time) of the recording material was evaluated.
A primer for bonding silicone rubber (No. 101 manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of the support plate washed with toluene and air-dried for 30 minutes. Next, a 5 mm thick silicone rubber sheet molded in advance was bonded to the surface of the support plate, and heat treated in an oven at 150 ° C. for 30 minutes.
Next, the surface of the silicone rubber layer formed by adhering the silicone rubber sheet on the support plate is spray-coated with a fluorine latex coating agent (Daikin Latex GLS-213F, manufactured by Daikin Industries, Ltd.), and the thickness is 10 μm (implemented). Example 4) and a surface layer having a thickness of 50 μm (Example 5) were formed to prepare pressure members.

Subsequently, the pressure member prepared in Example 1, the pressure member on which the surface layer having the thickness of 10 μm (Example 4) and the thickness of 50 μm (Example 5) is formed are shown in FIG. Wrinkle characteristics over time when a recording material is passed through an image forming apparatus (manufactured by Fuji Xerox Co., Ltd .: Color Printer DocuCenter Color 400) that is mounted on the apparatus 60 and has the fixing apparatus 60 under the following conditions. Evaluation was performed.
The recording material was passed through the image forming apparatus for 4 hours per day, kept on standby at 180 ° C. for 20 hours, and this operation was repeated to evaluate the durability. The paper wrinkle evaluation method (time-lapse paper wrinkle characteristic evaluation) was performed on the same standard as the initial paper wrinkle characteristic evaluation described above for five continuous sheets after a predetermined time. The results are shown in Table 2. In Example 4, the evaluation after 480 hours was not performed.

  From the results shown in Table 2, in the image forming apparatus including the fixing device equipped with the pressure member prepared in Example 4 and Example 5, paper wrinkles are generated when the initial five recording materials are continuously fed. I understand that I don't. Further, in the case of the pressure member coated with the fluororesin tube (Example 1), the paper wrinkle does not occur even over time as compared with the case of the pressure member coated with the fluorine latex (Examples 4 and 5). I understand.

1 is a schematic configuration diagram of an image forming apparatus to which the exemplary embodiment is applied. 1 is a side sectional view showing a configuration of a fixing device to which the exemplary embodiment is applied. It is a figure explaining the through-hole of a support plate. It is a figure explaining the metal mold | die which shape | molds the pressurization member to which this Embodiment is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1Y, 1M, 1C, 1K ... Image forming unit, 10 ... Primary transfer part, 11 ... Photosensitive drum, 12 ... Charger, 13 ... Laser exposure device, 14 ... Developing device, 15 ... Intermediate transfer belt, 16 ... Primary transfer Roll, 20 ... secondary transfer section, 60 ... fixing device, 61 ... fixing roll, 62 ... fixing belt, 64 ... pressure member, 64a ... rubber layer, 64b ... support plate, 64c ... peeling member, 64d ... heat resistant resin the film

Claims (8)

A pressure member that presses the belt member of the fixing device;
A support plate with through holes formed in the thickness direction;
A rubber layer laminated on the surface of the support plate on which the through hole is formed;
A pressurizing member comprising:   The pressure member according to claim 1, further comprising a fluororesin layer that covers a surface of the rubber layer.   The pressure member according to claim 1, wherein the through hole of the support plate is filled with rubber constituting the rubber layer. 2. The pressure member according to claim 1, wherein the rubber layer is formed by curing an addition reaction type silicone rubber composition containing the following components (A), (B) and (C): .
(A) Liquid organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by weight (B) Liquid organopolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule Hydrogen polysiloxane: 0.1 to 30 parts by weight (C) Addition reaction catalyst for reacting (A) and (B)   The diameter of the through hole is 0.1 mm to 3 mm, and the through hole is formed within a range of 1% to 60% of the surface of the support plate on which the rubber layer is laminated. Item 2. The pressure member according to Item 1. A method for manufacturing a fixing pressure member coated with a fluororesin tube,
The fluororesin tube is disposed in a mold having an inner circumferential length of 1.01 to 1.2 times the inner diameter of the fluororesin tube,
Injecting an addition reaction type silicone rubber composition inside the fluororesin tube disposed in the mold,
A method for producing a pressure member for fixing, wherein the addition reaction type silicone rubber composition injected into the inside of the fluororesin tube is cured. A rotating member for rotational driving;
A belt member that rotates to face the rotating member;
A pressure member that is disposed on the inner side of the belt member and includes a support plate having a through hole formed in the thickness direction and a silicone rubber layer laminated on the support plate;
The fixing device, wherein the pressure member presses the belt member against the rotating member. A toner image forming unit for forming a toner image;
A transfer portion for transferring the toner image onto a recording material;
A fixing unit that fixes the toner image transferred onto the recording material onto the recording material,
The fixing unit is
A rotating member that rotates and a belt member that rotates opposite to the rotating member and forms a nip portion through which the recording material passes.
A pressure member having a support plate disposed inside the belt member and having a through hole formed in the thickness direction and a silicone rubber layer laminated on the support plate;
A peeling member disposed adjacent to the pressure member via a heat resistant resin film provided between the pressure member and disposed in an exit region of the nip portion inside the belt member;
An image forming apparatus comprising:

Images