JP7172220B2 - Endless belt, fixing device, image forming apparatus, and endless belt manufacturing method - Google Patents

Description

The present invention relates to an endless belt, a fixing device, an image forming apparatus, and an endless belt manufacturing method.

2. Description of the Related Art In general, as a fixing device used in an image forming apparatus, one having an endless cylindrical fixing member (fixing belt) and a pressure roller is known. In such a fixing device, a nip portion is formed by the fixing member and the pressure roller, and the toner is fixed on the recording paper by applying pressure and heat to the nip portion.

As an endless belt used in such a fixing device, an endless belt having fine protrusions formed on the inner surface has been proposed (see, for example, Japanese Patent Application Laid-Open No. 2002-100003). In the endless belt described in Patent Literature 1, the convex portions are formed in a spherical shape to reduce the sliding resistance when sliding on the sliding member.

In order to further reduce the sliding resistance, a method of applying a lubricant to the inner surface of the endless belt is conceivable. However, the applied lubricant may leak from the widthwise ends as the endless belt rotates. If the lubricant leaks and the total amount decreases, the sliding resistance will increase. That is, it was difficult to keep the sliding resistance reduced by the lubricant.

SUMMARY OF THE INVENTION An object of the present invention is to provide an endless belt, a fixing device, an image forming apparatus, and a method for manufacturing an endless belt that can keep sliding resistance low during rotation.

In order to solve the above-described problems, the invention according to claim 1 is an endless belt manufacturing method for manufacturing an endless belt used in a fixing device, comprising: a plurality of mold rough surface portions extending along the circumferential direction; A plurality of mold flat portions arranged adjacent to the mold rough surface portion in the axial direction and having a surface roughness Rz smaller than that of the mold rough surface portion are arranged alternately on the outer peripheral surface of the cylindrical mold. On the other hand, a resin precursor solution was applied to the outer peripheral surface, and the resin precursor solution was dried and baked to form a resin film, and the outer peripheral surface of the cylindrical mold substrate was roughened by blasting. The endless belt manufacturing method is characterized in that the cylindrical mold having the mold rough surface portion and the mold flat portion is formed by subsequently polishing along the circumferential direction .

According to the endless belt of the present invention, since the rough surface portion is formed on the inner peripheral surface, when the lubricant is applied to the inner peripheral surface, the lubricant can be held in the concave portion of the rough surface portion. Lubricant is supplied from the concave portion to the convex portion during rotation, and sliding resistance can be reduced. In addition, the flat portion is likely to come into close contact with the object to be slid, making it difficult for the lubricant to pass therethrough. By arranging such a flat portion so as to be adjacent to the rough surface portion in the width direction, it becomes difficult for the lubricant held on the rough surface portion to flow in the width direction, and when the endless belt repeats rotation, In addition, the lubricant is less likely to leak from the ends in the width direction. Therefore, the sliding resistance during rotation of the endless belt can be kept low.

1 is a cross-sectional view showing a fixing device according to a first embodiment of the invention; FIG. 2 is a cross-sectional view showing an outline of an image forming apparatus provided with the fixing device; FIG. 3 is a plan view showing the inner peripheral surface of the endless belt of the fixing device; FIG. 4 is a perspective view showing a cylindrical mold for manufacturing the endless belt; FIG. FIG. 4 is a perspective view showing a state in which a mold base material is subjected to blasting treatment in order to manufacture the cylindrical mold. FIG. 4 is a cross-sectional view showing a state in which the mold base material is subjected to blasting; FIG. 4 is a cross-sectional view showing a state in which the mold base material is polished; FIG. 4 is a cross-sectional view showing a state in which a coating liquid is applied to the mold substrate; FIG. 4 is a cross-sectional view showing how the resin film formed by the coating liquid is released from the mold substrate. FIG. 5 is a cross-sectional view showing a fixing device according to a second embodiment of the invention; FIG. 5 is a cross-sectional view showing a fixing device according to a third embodiment of the invention; FIG. 11 is a cross-sectional view showing a fixing device according to a fourth embodiment of the invention; FIG. 11 is a cross-sectional view showing a fixing device according to a fifth embodiment of the invention; FIG. 11 is a cross-sectional view showing a fixing device according to a sixth embodiment of the invention; FIG. 2 is a cross-sectional view showing an outline of a testing device for evaluating the performance of the endless belt;

Hereinafter, each embodiment of the present invention will be described based on the drawings. In addition, in the second to sixth embodiments, the same reference numerals as in the first embodiment are given to the same constituent members and the constituent members having the same functions as the constituent members explained in the first embodiment, and the explanation thereof is omitted.

[First embodiment]
The fixing device 1 of the present embodiment is provided in an image forming apparatus (see FIG. 2) 100, and as shown in FIG. a nip forming member 5;

[Fixing device]
The endless belt 2 is a fixing belt made of polyimide. The surface layer of the belt has a release layer such as a PFA or PTFE layer, and has release properties so that toner does not adhere. An elastic layer formed of a silicone rubber layer or the like may be provided between the base material of the belt and the PFA or PTFE layer. In the absence of the silicone rubber layer, the heat capacity is reduced and the fixability is improved. Gloss unevenness (yuzu skin image) tends to remain. In order to improve this, it is preferable to provide the silicone rubber layer with a thickness of 100 μm or more. Deformation of the silicone rubber layer absorbs minute irregularities and improves the yuzu skin image.

A support member (stay) 6 for supporting the nip forming member 5 is provided inside the endless belt 2 to prevent bending of the nip forming member 5 that receives pressure from the pressure roller 4 and to maintain uniformity in the axial direction. A nip width can be obtained.

Further, the fixing device 1 is provided with a reflecting member 8 between the heating means 3 and the support member 6 to suppress wasteful energy consumption due to the support member 6 being heated by radiant heat from the heating means 3 or the like. there is Here, instead of providing the reflecting member 8, the surface of the supporting member 6 may be thermally insulated or mirror-finished to obtain the same effect.

The heating means 3 may be the illustrated halogen heater, but may also be an IH, a resistance heating element, a carbon heater, or the like. The endless belt 2 is directly heated from the inner peripheral side by the heating means 3 . If the heating means 3 is a halogen heater, the fixing device 1 may have a light blocking plate. The light blocking plate blocks the light emitted by the halogen heater so that the endless belt 2 is heated within a range corresponding to the size of the recording paper. The light-shielding plate has light-passing portions corresponding to various sizes of recording paper. there is

The pressure roller 4 is provided with an elastic rubber layer 4B on the outer side of the core metal 4A, and a release layer (PFA or PTFE layer) (not shown) is provided on the surface of the elastic rubber layer 4B in order to obtain release properties. ing. The pressure roller 4 rotates when a driving force is transmitted through gears from a driving source such as a motor provided in the image forming apparatus 100 shown in FIG. The pressure roller 4 is pressed against the endless belt 2 by a spring or the like, and has a predetermined nip width due to the elastic rubber layer 4B being crushed and deformed.

The pressure roller may be a hollow roller and may have a heating source such as a halogen heater. The elastic rubber layer may be made of solid rubber, but if there is no heater inside the pressure roller, sponge rubber may be used. It is more preferable to use sponge rubber, since the heat insulation is improved and the heat of the fixing sleeve is less likely to be lost.

The nip forming member 5 is arranged inside the endless belt 2 , that is, arranged on the opposite side of the pressure roller 4 with the endless belt 2 interposed therebetween. Thereby, a nip portion N is formed by the endless belt 2 and the pressure roller 4 which are arranged to face each other. The recording paper having the toner image transferred thereon passes through the nip portion N and is heated and pressurized to fix the toner image on the recording paper.

Although the shape of the nip portion N is flat in FIG. 1, it may be concave or other shapes. (When the shape of the nip portion is concave, the discharge direction of the leading edge of the recording paper is closer to the pressure roller, which improves separability and suppresses the occurrence of jams.)

The nip forming member 5 is provided with a fabric impregnated with a lubricant, and supplies the lubricant to the inner peripheral surface 2A of the endless belt 2 . Examples of lubricants include silicone oil and grease.

The endless belt 2 rotates together with the rotation of the pressure roller 4 . In the embodiment shown in FIG. 1, the pressure roller 4 is rotated by the drive source, and the endless belt 2 is rotated by the drive force being transmitted to the belt at the nip portion N. As shown in FIG. The endless belt 2 is nipped in the nip portion N and rotated, and is guided by holding members inserted at both ends of the belt other than the nip portion N and runs. In this way, the endless belt 2 is supported by the support member 6 arranged inside thereof so that the entire belt has a substantially cylindrical shape.

With the above configuration, it is possible to realize a fixing device that is inexpensive and warms up quickly.

[Image forming apparatus]
Next, the configuration of the image forming apparatus 100 using the configuration described above will be described with reference to FIG.

The image forming apparatus 100 shown in FIG. 2 is a color printer using a tandem system in which image forming units for forming a plurality of color images are arranged side by side along the stretching direction of the belt. The present invention is not limited to this method, and can be applied not only to printers but also to copying machines, facsimile machines, and the like.

In FIG. 2, image forming apparatus 100 includes photosensitive drums 20Y, 20C, and 20M as image carriers capable of forming images corresponding to colors separated into yellow, cyan, magenta, and black. A tandem structure in which 20Bk is arranged side by side is adopted.

In the image forming apparatus 100 configured as shown in FIG. 2, the visible images formed on the respective photoreceptor drums 20Y, 20C, 20M and 20Bk face the respective photoreceptor drums 20Y, 20C, 20M and 20Bk in the direction of the arrow A1. A primary transfer process is performed on an intermediate transfer member (hereinafter referred to as a transfer belt) 11 using an endless belt that can be moved to superimpose each image. After that, a secondary transfer process is performed on the recording paper S, such as a recording sheet, so that the images are collectively transferred.

Around the photosensitive drums 20Y, 20C, 20M and 20Bk, image forming means are arranged for image forming processing according to the rotation of the photosensitive drums 20Y, 20C, 20M and 20Bk. Here, when the photosensitive drum 20Bk for forming a black image is described as an object, a charging device 30Bk for performing an image forming process along the rotation direction of the photosensitive drum 20Bk, a developing device 40Bk, a primary transfer roller 12Bk, A cleaning device 50Bk is arranged. An optical writing device 60 is used for writing after charging.

In the superimposed transfer onto the transfer belt 11, the visible images formed on the respective photosensitive drums 20Y, 20C, 20M, and 20Bk are superimposed and transferred to the same position on the transfer belt 11 while the transfer belt 11 moves in the A1 direction. be done. That is, voltage is applied by the primary transfer rollers 12Y, 12C, 12M, and 12Bk arranged facing the respective photosensitive drums 20Y, 20C, 20M, and 20Bk with the transfer belt 11 interposed therebetween. The timing is shifted toward

The photosensitive drums 20Y, 20C, 20M, and 20Bk are arranged in this order from the upstream side in the A1 direction. Photoreceptor drums 20Y, 20C, 20M, and 20Bk are provided in image stations for forming yellow, cyan, magenta, and black images, respectively.

The image forming apparatus 100 includes four image stations that perform image forming processing for each color, and is arranged above the photosensitive drums 20Y, 20C, 20M, and 20Bk so as to face each other. , 12C, 12M, and 12Bk; a secondary transfer roller 14, which is a transfer roller as a transfer member that is arranged to face the transfer belt 11 and follows and rotates with the transfer belt 11; An intermediate transfer belt cleaning device 13 is disposed facing the transfer belt 11 to clean the transfer belt 11, and an optical writing device serving as an optical writing device is disposed facing the lower portion of these four image stations. a device 60;

The optical writing device 60 is equipped with a semiconductor laser as a light source, a coupling lens, an f.theta. The optical writing device 60 supplies writing light Lb corresponding to each color to each of the photosensitive drums 20Y, 20C, 20M, and 20Bk (in FIG. 2, for the sake of convenience, only the black image image station is labeled). However, other image stations are substantially similar) to form electrostatic latent images on the photosensitive drums 20Y, 20C, 20M, and 20Bk.

The image forming apparatus 100 includes a sheet feeding device 70 as a sheet feeding cassette on which the recording sheet S conveyed between the photosensitive drums 20Y, 20C, 20M, and 20Bk and the transfer belt 11 is stacked; The recording paper S conveyed from the feeding device 70 is transferred to the transfer section between each of the photosensitive drums 20Y, 20C, 20M, and 20Bk and the transfer belt 11 at a predetermined timing that matches the formation timing of the toner image by the image station. and a sensor (not shown) for detecting that the leading edge of the recording paper S has reached the registration roller pair 81 .

The image forming apparatus 100 includes a fixing device 1 as fixing means for fixing the toner image onto the recording paper S to which the toner image has been transferred, and ejects the fixed recording paper S to the outside of the main body of the image forming apparatus 100. A paper discharge roller 82, a paper discharge tray 83 arranged at the upper part of the main body of the image forming apparatus 100 and for stacking the recording paper S discharged to the outside of the main body of the image forming apparatus 100 by the paper discharge roller 82, and a paper discharge tray 83. Toner bottles 9Y, 9C, 9M, and 9Bk filled with yellow, cyan, magenta, and black toners are provided below.

The transfer belt unit 10 includes the transfer belt 11, primary transfer rollers 12Y, 12C, 12M, and 12Bk, as well as a driving roller 15 and a driven roller 16 around which the transfer belt 11 is wound.

The driven roller 16 also functions as a tension biasing means for the transfer belt 11, and for this reason, the driven roller 16 is provided with biasing means using a spring or the like. The transfer belt unit 10, the primary transfer rollers 12Y, 12C, 12M, 12Bk, the secondary transfer roller 14, and the cleaning device 13 constitute the transfer device 10A.

The sheet feeding device 70 is arranged in the lower part of the main body of the image forming apparatus 100 and has a feeding roller 84 as a feeding roller that contacts the upper surface of the uppermost recording sheet S. As shown in FIG. By rotating the feeding roller 84 in the counterclockwise direction, the uppermost recording sheet S is fed toward the registration roller pair 81 .

Although not shown in detail, the cleaning device 13 provided in the transfer device 10A has a cleaning brush and a cleaning blade arranged to face and contact the transfer belt 11 . The transfer belt 11 is cleaned by scraping and removing foreign matter such as residual toner on the transfer belt 11 with a cleaning brush and a cleaning blade.

The cleaning device 13 has discharge means (not shown) for carrying out and discarding residual toner removed from the transfer belt 11 .

The image forming apparatus 100 further includes an operation panel (not shown) for operating the entire apparatus, and control means (not shown) for controlling the entire apparatus.

When the number of sheets passed, the operating time, the number of revolutions of the endless belt 2, etc., reaches or exceeds a predetermined value, the control means causes the operation panel to display that maintenance of the endless belt 2 is required (maintenance display). A panel functions as display means. That is, the control means causes the operation panel to display the necessity of maintenance at predetermined operation intervals. When the maintenance is performed, the control means stops the maintenance display and restarts counting the number of sheets passed, the operation time, the number of revolutions of the endless belt 2, and the like.

[Endless belt]
Next, details of the endless belt 2 used in the fixing device 1 will be described with reference to FIG. The inner peripheral surface 2A of the endless belt 2 is formed with a plurality of rough surface portions 21A-21E extending along the circumferential direction and a plurality of flat portions 22A-22D extending along the circumferential direction. The circumferential direction of the endless belt 2 substantially coincides with the traveling direction of the endless belt 2 as it rotates as described above.

Each of the plurality of flat portions 22A-22D is arranged between the plurality of rough surface portions 21A-21E, and the flat portions 22A-22D and the rough surface portions 21A-21E are arranged alternately. That is, the flat portions 22A to 22D are arranged so as to be adjacent to the rough surface portions 21A to 21E in the width direction. The width direction of the endless belt 2 is a direction along the inner peripheral surface 2A and substantially orthogonal to the circumferential direction.

The surface roughness Rz of the rough surface portions 21A to 21E is preferably 1 μm or more and 10 μm or less, more preferably 3 μm or more and 6 μm or less. If the surface roughness Rz of the rough surface portions 21A to 21E is too small, the amount of lubricant that can be held in the concave portions of the rough surface portions 21A to 21E is reduced, and the endless belt 2 repeatedly rotates, resulting in insufficient lubricant. Otherwise, the contact area with the nip forming member 5 may become large and the coefficient of friction may become large.

On the other hand, if the surface roughness Rz of the rough surface portions 21A to 21E is too large, the convex portions of the rough surface portions 21A to 21E are scraped and worn by friction, or the lubricant held in the concave portions is difficult to supply to the convex portions. There is a possibility that it will become and end.

The surface roughness Rz of the flat portions 22A-22D is smaller than the surface roughness Rz of the rough surface portions 21A-21E. The surface roughness Rz of the flat portions 22A to 22D is preferably 1 μm or less, more preferably 0.3 μm or less. If the surface roughness Rz of the flat portions 22A to 22D is too large, it becomes difficult for the flat portions 22A to 22D to adhere to the sliding object (stretched member), and the rough surface portion 21A straddles the flat portions 22A to 22D. There is a possibility that the lubricant may easily move between ∼21E.

The width dimension of the flat portions 22A to 22D is preferably 0.5 mm or more and 10 mm or less, more preferably 1 mm or more and 6 mm or less. If the width dimension of the flat portions 22A to 22D is too small, the lubricant may easily move between the rough surface portions 21A to 21E so as to straddle the flat portions 22A to 22D.

On the other hand, if the widthwise dimension of the flat portions 22A to 22D is too large, the friction coefficient is greater than that of the rough surface portions 21A to 21E, and the region in which it is difficult to retain the lubricant is widened on the inner peripheral surface 2A of the endless belt 2. There is a possibility that the sliding resistance will increase.

In the inner peripheral surface 2A, the total area of the rough surface portions 21A-21E is wider than the total area of the flat portions 22A-22D. Thereby, sliding resistance can be reduced.

[Manufacturing method of endless belt]
The above-described endless belt 2 includes a coating process of coating and drooling a coating liquid on the outer peripheral surface 201 of a cylindrical mold 200 as shown in FIG. 4, a drying process of removing the solvent of the coating liquid by heating, It is manufactured by sequentially performing a baking step of imidizing the polyimide precursor by heating and a releasing step of releasing the formed resin film from the cylindrical mold 200 .

First, details of the cylindrical mold 200 will be described. On the outer peripheral surface 201 of the cylindrical mold 200, a mold rough surface portion 202 extending along the circumferential direction and a mold flat portion 203 arranged so as to be adjacent to the mold rough surface portion 202 in the axial direction are formed. It is That is, the mold rough surface portion 202 forms the rough surface portions 21A to 21E on the endless belt 2, and the mold flat portion 203 forms the flat portions 22A to 22D on the endless belt 2. FIG.

The surface roughness Rz of the mold rough surface portion 202 is preferably 1 μm or more and 10 μm or less, and more preferably 3 μm or more and 6 μm or less. Further, the surface roughness Rz of the mold flat portion 203 is smaller than the surface roughness Rz of the mold rough surface portion 202 . The surface roughness Rz of the mold flat portion 203 is preferably 1 μm or less, more preferably 0.3 μm or less. Also, the axial dimension of the mold flat portion 203 is preferably 0.5 mm or more and 10 mm or less, and more preferably 1 mm or more and 6 mm or less. In the outer peripheral surface 201 of the cylindrical mold 200 , it is preferable that the total area of the mold rough surface portion 202 is larger than the total area of the mold flat portion 203 .

In the endless belt 2 manufactured by the cylindrical mold 200, the surface roughness Rz of the rough surface portions 21A to 21E is substantially equal to the surface roughness Rz of the mold rough surface portion 202, and the surface roughness of the flat portions 22A to 22D is approximately the same. Rz becomes substantially equal to the surface roughness Rz of the mold flat portion 203 .

Here, a method for forming the mold rough surface portion 202 and the mold flat portion 203 on the outer peripheral surface 201 of the cylindrical mold 200 will be described. First, as shown in FIG. 5, the cylindrical mold substrate 300 is blasted to roughen the entire outer peripheral surface as shown in FIG. The treatment for roughening is not limited to blasting, and may be cutting, embossing, filing, or the like. If the surface is roughened by blasting, it is possible to form independent concave and convex shapes that are not continuous in a certain direction.

In the blasting process, blasting particles such as alumina, zirconia, glass beads, steel, iron powder, etc. are blown onto the outer peripheral surface of the cylindrical mold base 300 with compressed air. The blasting particles may be spherical particles or amorphous particles.

If spherical blasting particles are used, crater-like round depressions are formed in the roughened region 301 . As a result, as will be described later, when the mold rough surface portion 202 is transferred to the endless belt 2 to form the rough surface portions 21A to 21E, it is possible to form spherical convex portions, which are less likely to be worn and less likely to cause frictional resistance. Low rough surface portions 21A to 21E can be provided. In addition, "the convex portion has a spherical shape" means that the surface shape of the convex portion is a part of a spherical surface.

The cylindrical mold base 300 may be plated with chromium, nickel, or the like. It is preferable that the timing of the plating treatment is before the surface roughening treatment so that the concave portions are not filled with the plating.

The blasting process may be performed while relatively moving the cylindrical mold base 300 and the nozzle 400 for spraying blast particles. For example, the cylindrical mold base 300 may be rotated around a rotation axis along the axial direction, and the nozzle 400 may be moved along the axial direction. In this manner, the nozzle 400 may be scanned over the cylindrical mold substrate 300 to roughen the entire outer peripheral surface.

Next, the outer peripheral surface of the cylindrical mold base 300 whose entire surface has been roughened is polished along the circumferential direction. That is, as shown in FIG. 7, a flat region 302 is formed on the outer peripheral surface of the cylindrical mold base 300 . The flat region 302 polished in this way becomes the mold flat portion 203 in the cylindrical mold 200 , and the roughened surface region 301 which is not polished becomes the mold rough surface portion 202 . The polishing method may be mechanical polishing such as buffing or chemical polishing such as etching.

As described above, by polishing the outer peripheral surface of the cylindrical mold substrate 300 after the surface roughening treatment, the mold flat portion 203 is raised to the same height as the bottom of the concave portion of the mold rough surface portion 202. can be formed. Therefore, in the endless belt 2 to be manufactured, the apexes of the convex portions of the rough surface portions 21A to 21E and the flat portions 22A to 22D are substantially equal in height, and the convex portions and the flat portions 22A to 22D are formed substantially at the same time. It can be brought into contact with a sliding object.

Next, a method for preparing the coating liquid will be described. First, an appropriate amount of carbon black is dispersed in a solution containing a polyimide precursor (polyamic acid) to prepare a carbon black dispersion, and the amount of carbon black is appropriately adjusted to prepare a carbon black dispersion (resin precursor solution ) is used as the coating liquid.

In the coating step, an appropriate amount of coating liquid 500 may be applied as shown in FIG. 8 so that the endless belt 2 obtained after baking has a desired thickness. It should be noted that a thin film may be formed in one cycle, and a desired film thickness may be obtained by repeating a plurality of cycles, with the coating process, the drying process, and the baking process described above being one cycle.

In the coating step, the coating liquid 500 may be applied and poured by an appropriate method such as centrifugal molding, roll coating, blade coating, ring coating, dipping, spray coating, dispenser coating, die coating, or the like. At this time, in order to impart slidability to the inner surface of the endless belt 2, it is preferable to employ roll coating, dispenser coating, ring coating, or die coating.

The thickness of the endless belt 2 is preferably 60 μm or more and less than 120 μm, more preferably less than 100 μm. If the endless belt 2 is too thin, the mechanical strength of the endless belt 2 may be reduced, causing cracks or the like, and the durability may be reduced. On the other hand, if the endless belt 2 is too thick, there is a possibility that toughness will decrease and durability will decrease. Further, the endless belt 2 preferably has a small film thickness unevenness in order to improve running stability.

In the drying step, a heating means such as a hot air dryer, an IH heater, or a far-infrared heater may be used for drying at a temperature of about 80 to 150° C. for 10 to 60 minutes. In the firing step, for example, the same heating means may be used, and the temperature may be raised at a temperature rising rate of about 2 to 5°C/min following the drying step, and imidization firing may be performed at 300 to 400°C. Thereby, a resin film 600 is formed.

In the mold release step, the cylindrical mold 200 is cooled. Thereby, the resin film 600 is released from the cylindrical mold 200 as shown in FIG. The endless belt 2 is manufactured by laminating a silicone rubber layer, a fluorine resin layer, or the like on the resin film 600 that has been released from the mold, and performing processing such as cutting the ends.

According to this embodiment, the following effects are obtained. That is, since the rough surface portions 21A to 21E are formed on the inner peripheral surface 2A of the endless belt 2, when lubricant is applied to the inner peripheral surface 2A, the lubricant is held in the concave portions of the rough surface portions 21A to 21E. During rotation, the lubricant is supplied from the concave portion to the convex portion, and the sliding resistance can be reduced.

In addition, the flat portions 22A to 22D are likely to come into close contact with the sliding object, and it is difficult for the lubricant to pass therethrough. Since the flat portions 22A to 22D are arranged so as to be adjacent to the rough surface portions 21A to 21E in the width direction, the lubricant held on the rough surface portions 21A to 21E is less likely to flow in the width direction. When the endless belt 2 repeats rotation, the lubricant is less likely to leak from the ends in the width direction. Therefore, the sliding resistance during rotation of the endless belt 2 can be kept low.

Further, in the endless belt 2 produced by polishing the outer peripheral surface of the cylindrical mold substrate 300 after the surface roughening treatment, the convex portions of the rough surface portions 21A to 21E and the flat portions 22A to 22D rub substantially simultaneously. Being able to come into contact with the moving object makes it possible to reduce the contact area of the rough surface portions 21A to 21E and reduce the sliding resistance, while suppressing the movement of the lubricant on the flat portions 22A to 22D.

[Second embodiment]
The fixing device 1B of this embodiment is provided in the image forming apparatus 100, and as shown in FIG. a heating roller 802, a pressure roller 803, and a pressure pad 804 as a nip forming member.

The endless belt 2 is stretched over a pressure pad 804 and a driving roller 801 and a heating roller 802 as stretched members. As the driving roller 801 rotates, the endless belt 2 is driven (rotated). Inside the heating roller 802, a heat source 802A configured by a halogen heater or the like is provided. The heating roller 802 is rotated following the endless belt 2 .

The pressure pad 804 is arranged at a position facing the pressure roller 803 with the endless belt 2 interposed therebetween, and presses the pressure roller 803 to form a nip portion. The pressure pad 804 is made of, for example, a metal member such as stainless steel as a base material, and the surface (sliding surface) thereof is coated with a fluororesin to reduce the sliding resistance.

In the illustrated example, lubricating oil 805 is stored on the upstream side and downstream side of the pressure pad 804 inside the endless belt 2, but the inner peripheral surface 2A of the endless belt 2 is stored at other positions. may be lubricated.

[Third Embodiment]
A fixing device 1C of this embodiment is provided in an image forming apparatus 100, and as shown in FIG. , a folder 903 , and a heating means 904 .

The heating means 904 is composed of, for example, a heat generating member such as a PTC element, and is provided on a plate-shaped base material 905 . A base material 905 is held by a folder 903 , and the folder 903 is supported by a stay 902 . The surface of the substrate 905 on which the heating means 904 is provided is covered with an insulating layer 906 made of, for example, heat-resistant glass. A thin overcoat layer may be provided instead of the insulating layer 906 .

The endless belt 2 is sandwiched between the insulating layer 906 of the base material 905 and the pressure roller 901 to form a nip portion. That is, the base material 905 functions as a nip forming member facing the pressure roller 901 via the endless belt 2 . That is, in the fixing device 1C of the present embodiment, the nip forming member is provided with a heating means, and the endless belt 2 is heated at the nip portion. Lubricant is supplied to the inner peripheral surface 2A of the endless belt 2 as in the first embodiment.

[Fourth embodiment]
A fixing device 1D of this embodiment is provided in an image forming apparatus 100, and as shown in FIG. , a heating means 904 , an auxiliary stay 907 , a nip forming member 908 and a pressing roller 909 .

The nip forming member 908 is supported by the stay 902 and faces the pressure roller 901 via the endless belt 2 to form a nip portion. Auxiliary stay 907 is supported on the opposite side of nip forming member 908 by stay 902 . A base member 905 provided with a heating means 904 is supported by the auxiliary stay 907 .

The pressure roller 909 is arranged on the opposite side of the pressure roller 901 with respect to the stay 902 and sandwiches the endless belt 2 between itself and the insulating layer 906 of the base material 905 . That is, the endless belt 2 is heated while being sandwiched between the substrate 905 and the pressure roller 909 on the opposite side of the pressure roller 901 .

[Fifth embodiment]
A fixing device 1E of this embodiment is provided in an image forming apparatus 100, and as shown in FIG. , a heating means 904B, an auxiliary stay 907, and a nip forming member 908.

In this embodiment, instead of the flat base material 905 as in the fourth embodiment, a base material 905B having an arc-shaped cross section is provided to match the curvature of the endless belt 2 . The heating means 904B and the insulating layer 906B are also formed to have an arcuate cross section corresponding to the shape of the base material 905B. As a result, the insulating layer 906B of the base material 905B is along the inner peripheral surface 2A of the endless belt 2, and the length of the contact portion in the circumferential direction is longer than in the configuration using the flat base material. ing. Note that the pressing roller 909 may also be provided in this embodiment.

[Sixth embodiment]
The fixing device 1F of this embodiment is provided in the image forming apparatus 100, and as shown in FIG. , a folder 903, a heating means 904, a nip forming member 908, a second stay 910, and a heating belt 911. The fixing belt and the heating belt are provided separately.

The heating belt 911 is configured, for example, in the same manner as the endless belt 2 and is arranged around the stay 902 . Thereby, the heat generated by the heating means 904 is transmitted to the pressure roller 901 via the heating belt 911 . Since the pressure roller 901 is in contact with the endless belt 2 , the endless belt 2 is heated by the heating means 904 via the heating belt 911 and the pressure roller 901 .

The nip forming member 908 is supported by a second stay 910, around which the endless belt 2 is arranged. A recording sheet is passed through a nip portion formed by the pressure roller 901 and the nip forming member 908 .

According to the second to sixth embodiments as described above, rough surface portions 21A to 21E and flat portions 22A to 22D are formed on the inner peripheral surface 2A of the endless belt 2 in the same manner as in the first embodiment. Thus, the sliding resistance during rotation of the endless belt 2 can be kept low.

It should be noted that the present invention is not limited to the above-described embodiments, but includes other configurations and the like that can achieve the object of the present invention, and the following modifications and the like are also included in the present invention.

For example, in the above embodiment, five rough surface portions 21A to 21E and four flat portions 22A to 22D are formed on the inner peripheral surface 2A of the endless belt 2. The number should be set appropriately. Further, even if the number of flat portions is equal to or greater than the number of rough surface portions, that is, the widthwise edge of the inner peripheral surface of the endless belt may be flat portions.

In addition, although the best configuration, method, etc. for carrying out the present invention have been disclosed in the above description, the present invention is not limited thereto. That is, although the present invention has been particularly illustrated and described primarily with respect to certain embodiments, it is possible to apply the invention to such embodiments without departing from the spirit and scope of the invention. Various modifications can be made by the trader.

Therefore, the descriptions limited to the shapes, materials, etc. disclosed above are provided as examples to facilitate understanding of the present invention, and are not intended to limit the present invention. The description by the name of the member that removes some or all of the limitations on the shape, material, etc. is included in the present invention.

[Processing of cylindrical mold]
A mold substrate having an outer diameter of 120 mm and a length (axial dimension) of 450 mm was subjected to blasting treatment using glass bead particles as blasting particles to roughen the entire outer peripheral surface. After that, the flat part was formed by polishing the blasted surface in a belt shape.

[Preparation of Polyimide Precursor Coating Solution]
MA100 (manufactured by Mitsubishi Chemical Corporation), U varnish S (manufactured by Ube Industries, Ltd.), and N-methyl-2-pyrrolidone are used as the constituent materials of the acidic carbon black dispersion, and these are subjected to a ball mill at a rotation speed of 1500 rpm. and stirred for about 10 minutes to form an acidic carbon black dispersion.

In addition, Ketjenblack EC300J, U varnish S (manufactured by Ube Industries, Ltd.), and N-methyl-2-pyrrolidone are used as the constituent materials of the conductive carbon black dispersion, and these are stirred by a ball mill for about 10 minutes. , a conductive carbon black dispersion.

The acidic carbon black dispersion and the conductive carbon black dispersion were mixed and mixed and defoamed by a centrifugal stirring and defoaming machine to obtain a coating liquid.

[Belt molding method]
A cylindrical mold surface-treated as described above was used as a mold and attached to a roll coater. Next, the coating liquid was poured into a pan, and the coating liquid was pumped up by the application roller to control the thickness of the coating liquid on the application roller. After uniformly transferring and coating the coating liquid on the coating roller onto the outer peripheral surface of the cylindrical mold, the cylindrical mold was placed in a hot air circulation dryer while maintaining the rotation of the cylindrical mold, heated, and stopped rotating. . After that, it was introduced into a heating furnace (calcining furnace) capable of high-temperature treatment and subjected to heat treatment (firing). The polyimide resin (resin film) imide-cured by baking was removed from the cylindrical mold while being pulled out, to prepare an endless belt made of polyimide resin.

[Evaluation test]
A test apparatus 701 shown in FIG. 15 was used to evaluate the performance of the endless belt produced as described above. The testing device 701 includes a drive roller 703 , a nip forming member 704 , tension rollers 705 and 706 and a pressure roller 707 . The test was conducted by stretching the endless belt 2 between the driving roller 703, the nip forming member 704, and the tension rollers 705 and 706. FIG.

The nip forming member 704 is made of fluororesin and has an embossed inner peripheral surface. The tension rollers 705 and 706 are rollers around which the endless belt 2 is stretched. to give The endless belt 2 was nipped between the nip forming member 704 and the pressure roller 707 facing the outer peripheral surface of the belt, and a certain amount of lubricating oil was applied as a lubricant to the inner peripheral surface 2A.

When the endless belt 2 is driven by rotating the driving roller 703 , friction is generated between the inner peripheral surface 2</b>A and the nip forming member 704 . The motor torque required to drive the driving roller 703 was evaluated initially and after 100 hours of driving.

[Test results]
Table 1 shows the surface roughness Rz and the widthwise dimension of the rough surface portion and the surface roughness Rz and the widthwise dimension of the flat portion of the endless belts of Examples 1 to 9. Table 1 also shows the results of the above evaluation test.

In any of Examples 1 to 9, the increase in required motor torque after 100 hours of driving was small, and good results were obtained. In particular, good results were obtained in Examples 1-4.

Reference Signs List 1 fixing device 2 endless belt 2A inner peripheral surface 21A to 21E rough surface portion 22A to 22D flat portion 3 heating means 4 pressure roller 5 nip forming member 6 support member (stay)
705, 706 tension rollers (suspended members)
REFERENCE SIGNS LIST 100 image forming apparatus 200 cylindrical mold 201 outer peripheral surface 202 mold rough surface portion 203 mold flat portion 300 cylindrical mold substrate 600 resin film

JP 2004-109665 A

Claims (4)

An endless belt manufacturing method for manufacturing an endless belt used in a fixing device, comprising:
A plurality of mold rough surface portions extending along the circumferential direction, and a plurality of mold flat portions arranged adjacent to the mold rough surface portion in the axial direction and having a surface roughness Rz smaller than that of the mold rough surface portion. and apply a resin precursor solution to the outer peripheral surface of a cylindrical mold alternately arranged on the outer peripheral surface,
forming a resin film by drying and baking the resin precursor solution ;
The outer peripheral surface of the cylindrical mold substrate is roughened by blasting and then polished along the circumferential direction to form the cylindrical mold having the mold rough surface portion and the mold flat portion. An endless belt manufacturing method characterized by: 2. The endless belt according to claim 1 , wherein the mold rough surface portion has a surface roughness Rz of 1 μm or more and 10 μm or less, and the mold flat portion has a surface roughness Rz of 1 μm or less. Production method. 3. The endless belt manufacturing method according to claim 1 , wherein the total area of said mold rough surface portion is larger than the total area of said mold flat portion. The endless belt manufacturing method according to any one of claims 1 to 3 , characterized in that the axial dimension of the mold flat portion is 0.5 mm or more and 10 mm or less.

Images