JP2005266519A - Fixing belt and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing belt contributing to the miniaturization of an image forming apparatus, and the image forming apparatus equipped with the fixing belt. <P>SOLUTION: The fixing belt is provided with: an annular belt base material; an elastic body layer winding round the center part in a width direction on the surface of the belt base material and holding a recording medium with a predetermined member in between; adhesive layers winding round both end parts on the surface of the belt base material; and reinforcing layers winding round both end parts on the surface of the belt base material while the back surfaces are brought into contact with the surfaces of the adhesive layers and having higher strength than the elastic body layer. The edge of the adhesive layer on the elastic body layer side is covered with the elastic body layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fixing belt for fixing a toner image onto a recording medium by sandwiching a recording medium to which the toner image has been transferred with a predetermined member, and an image forming apparatus including such a fixing belt. About.

  An image forming apparatus such as a copying machine forms a toner image on an image carrier, and finally transfers and fixes the toner image on a recording medium to form an image composed of a fixed toner image on the recording medium. Are known. Conventionally, a roll fixing method has been mainly used in the fixing devices that perform the above-described fixing of these image forming apparatuses.

  In this roll fixing method, a recording medium onto which a toner image has been transferred is passed between a heating roll and a pressure roll (nip portion) arranged opposite to each other so that the toner image is in contact with the heating roll. The toner image is fixed on the recording medium by applying pressure while heating.

  In recent years, an endless heating belt is used instead of the heating roll for the purpose of obtaining a fixed image that is clearer than the fixing image obtained by the roll fixing method, and the nip is formed between the heating belt and the pressure roll. There has been proposed a belt fixing system in which a part is formed, or a pressure roll is replaced with an endless pressure belt and a nip portion is formed by a heating belt and a pressure belt.

  A heating belt used in this belt fixing system is further proposed in which a fluorocarbon siloxane rubber layer is circulated on the outer surface of the belt base material in order to finish the toner image fixed on the image recording medium with high gloss. (For example, refer to Patent Document 1).

  However, when such a belt is disposed in a fixing device in an actual image forming apparatus, if the roundness and straightness of a plurality of rolls stretching the belt are low, the belt meanders in the width direction. May occur. In recent years, the size of the equipment has been reduced, and members have been placed right next to the belt that circulates. If the amount of meandering of the belt is large, the end face of the belt will crack after a short period of use due to contact with surrounding members. Various adverse effects on the fixing process are expected.

  Thus, it is conceivable to attach a reinforcing tape to both ends of the belt.

  However, if this is done, the adhesive component may protrude from the rubber layer on the belt surface due to heat or the like, and it must be avoided that the adhesive component adheres to the recording medium.

For this reason, when the belt end portion is reinforced by sticking the reinforcing tape to both end portions of the belt, it is necessary to ensure a sufficient belt width.
Japanese Patent No. 2903972

  However, as the demand for smaller devices is increasing, efforts to keep the belt width to a minimum have become necessary.

  In view of the above circumstances, an object of the present invention is to provide a fixing belt that contributes to downsizing of the apparatus and an image forming apparatus including such a fixing belt.

The fixing belt of the present invention that achieves the above object is as follows.
In the fixing belt for fixing the toner image on the recording medium by sandwiching the recording medium which has received the transfer of the toner image between the predetermined member,
An annular belt substrate;
An elastic body layer that wraps around the central portion in the width direction on the surface of the belt base material and sandwiches the recording medium with the predetermined member;
An adhesive layer that wraps around both end portions on the surface of the belt substrate;
A reinforcing layer having a strength higher than that of the elastic body layer, having a back surface adhered to the surface of the adhesive layer, and circulating both end portions on the belt base material surface;
The adhesive layer is characterized in that the edge on the elastic layer side is covered with the elastic layer.

  In the fixing belt according to the present invention, the elastic layer side of the adhesive layer that circulates at both end portions on the surface of the belt base material is covered with the elastic body layer that circulates in the center portion in the width direction on the surface of the belt base material. This prevents the adhesive component from protruding from the adhesive layer to the surface of the elastic layer, and the fixing belt of the present invention ensures a width for avoiding adhesion of the adhesive component to the recording medium passing through the surface. Is no longer necessary. Therefore, according to the fixing belt of the present invention, it is possible to contribute to downsizing of the apparatus.

  Here, the surface of the reinforcing layer and the back surface of the elastic body layer are preferably overlapped.

  By doing so, it is possible to more reliably prevent the adhesive component from protruding to the surface of the fixing belt.

  It is also a preferred aspect that the elastic layer is made of a fluorocarbon siloxane rubber.

  In this way, the toner releasability of the elastic layer can be improved. For this reason, it can also contribute to the improvement of image quality.

  Here, the reinforcing layer is preferably made of a polyimide base material or a polyester base material.

  Thus, if a reinforcement layer is formed with a heat resistant thing, a reinforcement layer can be prolonged.

  It is also a preferable aspect that the adhesive layer is made of a silicone adhesive, an acrylic adhesive, or a thermosetting rubber adhesive.

  As described above, when the adhesive layer has heat resistance, liquefaction due to heat denaturation is suppressed, so that it is possible to more reliably prevent the adhesive component from protruding from the adhesive layer to the surface of the elastic layer.

Further, the elastic layer is formed on the surface of the belt base material by being applied to the belt base material on which the adhesive layer and the reinforcing layer are formed,
The combined thickness of the adhesive layer and the reinforcing layer is preferably 3 times or less the thickness of the elastic layer.

  In the belt base material on which the adhesive layer and the reinforcing layer are formed, both end portions are thicker than the center portion in the width direction of the belt base material. If the thickness of both ends is greater than necessary, the applied elastic component flows down to the center at the boundary between both ends and the center when the elastic component is applied, and the thickness of the boundary of the elastic layer Will become thinner and more likely to break. Therefore, by limiting the combined thickness of the adhesive layer and the reinforcing layer to the thickness of the elastic layer to be formed in this way, it is possible to prevent a thin elastic layer from being formed at the boundary. The Thereby, it is possible to further reliably prevent the adhesive component from protruding by superimposing the surface of the reinforcing layer and the back surface of the elastic layer.

  It is also a preferable aspect that the width of the reinforcing layer is at least 5 mm or more.

  According to the image forming apparatus of the present invention including the fixing belt of the present invention, it is possible to cope with downsizing without adversely affecting the fixing process.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention including an embodiment of a fixing belt according to the present invention.

  As shown in FIG. 1, the printer 1 according to the present embodiment includes four image forming units 10Y, 10M, 10C, and 10K from the left in FIG. Photoconductors 11Y, 11M, 11C, 11K rotating in the direction, chargers 13Y, 13M, 13C, 13K, exposure units 14Y, 14M, 14C, 14K, developing units 12Y, 12M, 12C, 12K, and primary transfer roll 20Y , 20M, 20C, and 20K. The printer 1 can perform full-color printing, and the symbols Y, M, C, and K added to the end of each of the above components are yellow, magenta, cyan, and black images, respectively. It is a component for formation.

  The printer 1 is also provided with an intermediate transfer belt 30, a secondary transfer roll 40, and a tension roller 31 that circulate in the direction of arrow B.

  A basic image forming operation of the printer 1 will be described.

  In the printer 1, first, toner image formation by the yellow image forming unit 10 </ b> Y is started, and a predetermined charge is applied to the surface of the photoreceptor 11 </ b> Y rotating in the direction of arrow A by the charger 13 </ b> Y. Next, exposure light corresponding to the yellow image generated by the exposure device 14Y is irradiated onto the surface of the photoconductor 11Y to form an electrostatic latent image. The electrostatic latent image is developed with yellow toner by the developing device 12Y to form a yellow toner image on the photoreceptor 11Y. The toner image is transferred to the intermediate transfer belt 30 by the primary transfer roll 20Y.

  The intermediate transfer belt 30 receives the magenta toner image of the next color in accordance with the timing at which the yellow toner image transferred onto the intermediate transfer belt 30 reaches the primary transfer roll 20M of the image forming unit 10M of the next color. A toner image is formed by the magenta image forming unit 10M so as to reach the primary transfer roll 20M. The magenta toner image formed in this way is transferred onto the yellow toner image on the intermediate transfer belt 30 while being superimposed on the primary transfer roll 20M.

  Subsequently, toner image formation by the cyan and black image forming units 10C and 10K is performed at the same timing as described above, and sequentially superimposed on the yellow and magenta toner images of the intermediate transfer belt 30 in the primary transfer rolls 20C and 20K. Is transcribed.

  Thus, the multicolor toner image transferred onto the intermediate transfer belt 30 is finally secondarily transferred onto the paper 200 by the secondary transfer roll 40, and the multicolor toner image is conveyed along with the paper 200 in the direction of arrow C. 2 is sent to the fixing device shown in FIG.

  FIG. 2 is a schematic configuration diagram of a fixing device provided in the printer shown in FIG.

  FIG. 2 schematically shows a state in which the sheet 200 on which the toner image is secondarily transferred passes through the fixing device 50.

  2 includes a plurality of conveying rolls 51, a pair of heating and pressing rolls 52, an endless fixing belt 53 wound around an upper heating and pressing roll 52, and an upper pressing force. A suspension roll 54 around which the unsupported belt 53 is wound together with the heating roll 52, a heat sink 56 that cools the heated paper 200, and a peeling roll 55 that peels the cooled paper 200 from the endless belt 53. Yes. The details of the toner image fixing in the printer 1 are irrelevant to the present invention, and the description thereof is omitted.

  Hereinafter, the fixing belt 53 according to an embodiment of the fixing belt of the present invention, which is a component of the fixing device 50, will be described.

  FIG. 3 is an external view of the fixing belt shown in FIG.

  The fixing belt 53 shown in FIG. 3 includes a polyimide-based polymer belt base material 531, an elastic body layer 532 made of fluorocarbon siloxane rubber that circulates in the center in the width direction on the surface, and a polyimide-based material that reinforces both ends of the belt. And the reinforcing tape 533.

  The belt base material 531 is made of a cylindrical film prepared by dispersing acetylene black (20% by weight) in thermoplastic polyimide resin (80% by weight), and has a diameter of 168 mm, a width of 140 mm, thermal conductivity and heat resistance. To an endless belt having a thickness of 90 μm.

  The reinforcing tape 533 has a tape base layer 5331 having a higher strength than the fluorocarbon siloxane rubber and a tape adhesive layer 5332, and has a width of 5 mm and a total thickness of 60 μm. Since the fixing temperature in the fixing device 50 of the printer 1 reaches 130 ° C., a heat resistant polyimide-based material is used for the tape base material layer 5331.

  The tape adhesive layer 5332 employs a silicone-based material from the viewpoint of storage stability at high temperatures and stickability. Here, the reinforcing tape 533 includes a polyimide adhesive tape No. 1 manufactured by Nitto Denko Corporation. 360 UL was used.

  The elastic layer 532 is made of fluoroelastomer SIFEL615 of Shin-Etsu Chemical Co., Ltd., which is a fluorocarbon siloxane rubber. The thickness of the elastic layer 532 is 35 μm. By providing this elastic layer 532 on the outer surface of the belt, it is possible to set the belt surface hardness appropriately while maintaining the toner releasability equivalent to or higher than that of silicone rubber. Thus, the belt surface layer can be deformed to follow. That is, here, high gloss color copying is realized by uniformly melting the toner.

  4 is a cross-sectional view of the fixing belt shown in FIG.

  A dimension L shown in FIG. 4 indicates a width in which the surface of the reinforcing tape 533 and the back surface of the elastic body layer 532 are overlapped. By doing so, it is possible to prevent the adhesive component of the reinforcing tape 533 from protruding from the tape adhesive layer 5332 to the outermost surface of the fixing belt due to mechanical or thermal stress.

  If the total thickness of the reinforcing tape 533 is too thick compared to the thickness of the elastic layer formed by applying the liquid rubber composition, the belt of the reinforcing tape 533 is applied when the rubber composition is applied. Since the rubber composition applied to the rising surface on the center side is likely to sag, there is a risk that an elastic body layer portion that is more easily torn than other materials may be formed on this rising surface. Therefore, in the fixing belt 53, the total thickness of the reinforcing tape 533 is set to be three times or less than the thickness of the elastic body layer 532, thereby overlapping the surface of the reinforcing tape 533 and the back surface of the elastic body layer 532. It is possible to more reliably prevent leakage of the adhesive component due to the combination. In the fixing belt 53, the total thickness of the reinforcing tape 533 is 60 μm.

  FIG. 5 is a diagram showing a procedure for creating the fixing belt shown in FIGS. 3 and 4.

  FIG. 5 (a) shows a belt base material 531 of a polyimide polymer that has been subjected to a surface polishing treatment, and FIG. 5 (b) shows a belt base material 531 that has been subjected to a cleaning treatment. FIG. 5C shows a state where the reinforcing tape 533 is attached to both ends, and in FIG. 5C, a liquid fluorocarbonsiloxane rubber composition is applied to the belt base material 531 to which the reinforcing tape 533 is attached. It is shown that a fluorocarbon siloxane elastic body layer is formed by applying a coating process so as to overlap a part of the reinforcing tape 533. If there is no technical problem when the liquid fluorocarbonsiloxane rubber composition is applied to the belt substrate 531 and the reinforcing tape 533, the dimension L shown in FIG. 4 may be increased.

  In the above coating treatment, the fluoroelastomer SIFEL615, which is a liquid fluorocarbon siloxane rubber composition, is coated with the belt base material 531 and the reinforcing tape 533 by the dip coating method, and then the primary vulcanization at 120 ° C. for 30 minutes and 200 By performing secondary vulcanization at 2 ° C. for 2 hours, the fluorocarbon siloxane rubber composition is solidified and adhered to the belt base material 531. The primary and secondary vulcanization conditions are determined by how to set the coating thickness of the fluorine elastomer SIFEL 615 and the hardness of the elastic layer that affects the quality of the fixed image. Moreover, since the adhesiveness with the fluorocarbon siloxane elastic body layer 532 is higher than the polyester tape base material, the polyimide tape base material is used for the reinforcement tape 533.

  FIG. 6 is a view showing a test piece used for measuring the strength of a belt base material having a reinforcing tape attached to an end portion.

  The test piece shown in FIG. 6 was affixed with a reinforcing tape No. 360UL having a width of 5 mm as shown in FIG. 6 along a longitudinal end portion of a polyimide polymer having a size of 15 × 100 mm cut out from the belt equipment 531. The test piece was pulled in the longitudinal direction using a tensile tester, and the breaking force was measured 5 times. For comparison, a polyimide polymer of the same scale was also pulled in the longitudinal direction using a tensile tester, and the breaking force was measured 5 times. In addition, this measurement is performed after making a 1 mm incision in the transversal direction at the longitudinal center of all these test pieces. The breaking force of each test piece is shown in Table 1 below.

  Table 1 shows that the average value of those without the reinforcing tape 533 is 87.87N, and the average value of those having the reinforcing tape 533 is 130.63N. It was confirmed that the strength was about 1.5 times that of the case where it was not applied. Note that this experiment is a measurement of the breaking force after making a 1 mm incision in the lateral direction at the center in the longitudinal direction, and verifies the difference in the crack occurrence rate at the belt end. It is not a comparative experiment of reinforcement. However, it was confirmed that the belt end portion was reinforced against mechanical stress by attaching a reinforcing tape to the end portion of the belt.

  As described above, in the fixing belt 53 of the present embodiment, the back surface of the elastic body layer 532 that circulates the central portion in the width direction on the surface of the belt base material and the both ends in the width direction on the surface of the belt base material circulate. The surface of the reinforcing tape 533 is overlapped, and the elastic body layer side of the tape adhesive layer 5332 of the reinforcing tape 533 that wraps around both end portions on the surface of the belt base material is covered with the elastic body layer 532. . For this reason, protrusion of the adhesive component from the tape adhesive layer 5332 to the surface of the elastic body layer 532 is prevented. Therefore, according to the fixing belt 53 of the present embodiment, it is not necessary to secure a belt width for avoiding adhesion of adhesive components to the recording medium passing through the surface, which can contribute to downsizing of the apparatus. .

  In the above embodiment, a belt base material made of a polyimide polymer has been taken as an example, but this may be made of an organic polymer material such as polycarbonate, polysulfone, or a fluorine polymer, In addition, the tape base layer of the reinforcing tape is not limited to a polyimide base material, and may be a tape made of a heat-resistant resin, for example, a polyester base material. As the tape adhesive layer of the reinforcing tape, a silicone type is given as an example from the viewpoint of sticking to a belt base material. However, this may be an acrylic type or a thermosetting type, and is elastic. For the body layer, fluorocarbon siloxane rubber is taken as an example, but this may be silicone rubber or fluorine rubber.

1 is a schematic configuration diagram of an embodiment of an image forming apparatus of the present invention including an embodiment of a fixing belt of the present invention. It is a schematic block diagram of the fixing device with which the printer shown in FIG. 1 is equipped. FIG. 3 is an external view of the fixing belt shown in FIG. 2. FIG. 4 is a cross-sectional view of the fixing belt shown in FIG. 3. FIG. 5 is a diagram showing a procedure for creating the fixing belt shown in FIGS. 3 and 4. It is a figure which shows the test piece used for the intensity | strength measurement of the belt base material by which the reinforcement tape was affixed on the edge part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 50 Fixing device 51 Conveyance roll 52 Heating and pressing roll 53 Fixing belt 531 Belt base material 532 Elastic body layer 533 Reinforcement tape 5331 Tape base material layer 5332 Tape adhesive layer 54 Suspension roll 55 Peeling roll 56 Heat sink

Claims (2)

In the fixing belt for fixing the toner image on the recording medium by sandwiching the recording medium that has received the transfer of the toner image with a predetermined member,
An annular belt substrate;
An elastic body layer that sandwiches the recording medium with the predetermined member, which circulates in the center portion in the width direction on the surface of the belt base material;
An adhesive layer that circulates both end portions on the belt base material surface;
A reinforcing layer having a strength higher than that of the elastic layer, wherein the back surface is brought into contact with the surface of the adhesive layer, and both end portions on the belt base material surface are circulated.
The fixing belt, wherein the adhesive layer has an edge on the elastic layer side covered with the elastic layer. In an image forming apparatus for forming an image by forming a toner image on an image carrier, and finally transferring and fixing the toner image on a recording medium.
A fixing belt for fixing the toner image on the recording medium by sandwiching the recording medium that has received the transfer of the toner image with a predetermined member;
The fixing belt is
An annular belt substrate;
An elastic body layer that sandwiches the recording medium with the predetermined member, which circulates in the center portion in the width direction on the surface of the belt base material;
An adhesive layer that circulates both end portions on the belt base material surface;
A reinforcing layer having a strength higher than that of the elastic layer, wherein the back surface is brought into contact with the surface of the adhesive layer, and both end portions on the belt base material surface are circulated.
The image forming apparatus according to claim 1, wherein the adhesive layer has an edge on the elastic layer side covered with the elastic layer.

Images