Fixing device and heating device

Abstract

To solve problems of paper wrinkles and ink friction caused by stress applied to a recording material in a fixation nip part when one of upper and lower belts is slipped and a speed difference between the upper and lower belts is generated.SOLUTION: A belt inner surface is cleaned, which prevents slip after endurance. Cleaning members (webs) are arranged at opposite positions of outside / inside of the belt, which stabilizes cleaning performance and prevents the slip after the endurance. A conveyance roller for driving the belt is cleaned using the webs, which prevents the slip after the endurance.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fixing device that fixes an image on a recording material and an image forming apparatus equipped with the fixing device. [Background technology]

[0002] If the ink immediately after printing with an inkjet printing device is touched before it has dried sufficiently, the image may become distorted or the ink may get on your hands. Inkjet printing devices with high printing speeds may overlap a second sheet of printing material before the ink on the first sheet has dried, causing the back side of the first sheet to become dirty. For this reason, inkjet printing devices, particularly high-speed printing models, require a means to dry the ink and fix it on the printing material.

[0003] In high-speed inkjet recording devices, a thermal fixing method is used as a means for drying and fixing the ink, in which the recording material immediately after recording is heated to a high temperature suddenly. The image forming device disclosed in Patent Document 1 uses a method in which the recording material on which ink has been printed is sandwiched between a pair of belts and the ink is fixed to the recording material by applying heat and pressure (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-15290 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a fixing device that fixes ink onto a recording material by sandwiching the recording material between a pair of heated belts, one method of heating the belt is to heat the belt in a non-contact manner using radiant light from a halogen heater or the like.

[0006] In order to provide a high-speed, long-life fixing device, it is necessary to drive the upper and lower belts stably for a long period of time. If a speed difference occurs between the upper and lower belts due to slippage of one of the belts, stress is applied to the recording material in the fixing nip, causing problems such as paper wrinkles and ink rubbing.

[0007] The present invention has been developed in view of the above problems, and an object of the present invention is to propose a fixing device that can stably drive a belt even after long-term use in a configuration in which the belt is heated by a heater. [Means for solving the problem]

[0008] In order to achieve the above object, the fixing device of the present invention is a fixing device (100) that dries and fixes ink on a recording material, the fixing device having a belt (21, 31), a surface cleaning unit (80) that cleans the belt surface, and an inner surface cleaning unit (60) that cleans the belt inner surface, characterized in that the belt surface cleaning unit (80) and the belt inner surface cleaning unit (60) are arranged opposite each other across the belt (21, 31).

[0009] The fixing device includes a belt (21, 31), at least two rollers (22, 24, 32, 34) tensioning the belt (21, 31), and a drive roller driven by at least one of the rollers (22-24, 32-34) for driving the belt (21, 31), and dries and fixes ink on a recording material, the fixing device being characterized in that a cleaning unit (60, 70) is disposed on the drive roller. Effect of the Invention

[0010] According to the present invention, by cleaning the inner surface of the belt, it is possible to suppress contamination of the drive roller, and the belt can be driven stably for a long period of time. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a cross-sectional view of the fixing device according to the first embodiment. [Diagram 2] FIG. 11 is a cross-sectional view of a fixing device according to a second embodiment of the present invention. [Diagram 3] FIG. 4 is a cross-sectional view of a fixing device of a comparative example. [Figure 4] 13 is a diagram illustrating an example in which a cleaning unit is disposed on a lower belt unit. FIG. [Diagram 5] 13A and 13B are diagrams illustrating an example in which cleaning units are arranged on upper and lower belt units. [Figure 6] 4 is a cross-sectional view of the fixing device for explaining a belt heating method. [Figure 7] FIG. 11 is a cross-sectional view of a fixing device illustrating a cleaning unit according to a third embodiment of the present invention. [Figure 8] FIG. 11 is a cross-sectional view of a fixing device illustrating a cleaning unit according to a fourth embodiment of the present invention. [Figure 9] FIG. 4 is a cross-sectional view of a fixing device for explaining a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. Note that, although the following describes an example in which the present invention is applied to an inkjet type full-color image forming apparatus, the present invention is not limited to this, and can also be applied to various types of image forming apparatuses, monochrome image forming apparatuses, etc. EXAMPLES

[0013] The fixing device is a block diagram of an inkjet recording apparatus, which dries and fixes ink printed on a recording material by an inkjet method.

[0014] <Fixing device> The fixing device 100 is composed of an upper belt unit 20 and a lower belt unit 30, and a nip N is formed by pressing the upper and lower belts together.

[0015] The upper belt 21 is stretched around at least three rollers, an upper driving roller 22, an upper tension roller 23, and an upper steering roller 24. Similarly, the lower belt 31 is stretched around at least three rollers, a lower driving roller 32, a lower tension roller 33, and a lower steering roller .

[0016] The three rollers are common to the upper and lower units, and the tension roller and steering roller are metal rollers with an outer diameter of 50 mm and a thickness of 10 mm. They can be made of iron or aluminum. In this embodiment, aluminum metal rollers are used.

[0017] The upper and lower drive rollers 22, 32 are metal rollers with a rubber layer on the outside, which gives them a higher coefficient of friction with the inner surface of the belt than the other rollers. In this embodiment, a 5 mm thick rubber layer is provided on the outer periphery of an aluminum roller with an outer diameter of 40 mm. The type of rubber that can be used includes urethane rubber and silicone rubber. In this embodiment, urethane rubber is used.

[0018] When a motor (not shown) applies torque to the drive rollers, the upper belt 21 and the lower belt 22 rotate. The recording material S with an unfixed image thereon is transported in the direction of the arrow. By performing a long nip and heating with both the upper belt and the lower belt, the ink applied to the recording material S penetrates into the paper, achieving high print quality.

[0019] <Heating source> The heater 40 is a heat source disposed in the upper unit, and the side opposite the nip is covered by a reflector 41. The heater 40 can quickly apply heat to the image surface of the recording material S by directly heating the nip portion of the upper belt 21. The heater can be a halogen heater or a carbon heater. In this embodiment, a halogen heater is used. Since the heater 40 directly heats the belt, it has good thermal response, and by switching the output when switching the paper type, the fixing operation can be continued without waiting time.

[0020] The lower belt unit 30 is stretched by at least three rollers. The heater 42 is a halogen heater disposed in the lower steering roller 34. The lower belt 31 is heated by the lower steering roller 34 heated by the heater 42. The lower belt unit 30 can also directly heat the lower belt 31 by a halogen heater like the upper belt unit 20, but since the lower belt unit does not heat the image surface of the recording material S, it does not require a thermal response like the upper belt unit, and therefore a halogen heater in the steering roller is used as the heating source.

[0021] The upper belt and the lower belt form a nip N, which heats the ink and the recording material S. The ink applied to the recording material S permeates into the recording material S, and the image is fixed to the recording material S.

[0022] <Temperature control> Next, temperature control will be described.

[0023] The temperature sensor 50 is a sensor that monitors the temperature of the upper belt (21), and monitors the temperature of the belt after it has left the nip. Temperature control is performed so that the temperature detected by the temperature sensor 50 becomes a target temperature.

[0024] The target temperature should be determined so that the ink is fixed on the recording medium and the abrasion resistance is satisfactory, and the optimum temperature differs depending on the ink material. In this embodiment, the target temperature was set to 85°C.

[0025] The lower belt 31 is also subjected to temperature control in the same manner as the upper belt 21. A temperature sensor 51 monitors the belt temperature after it has left the nip, and the temperature is controlled to a target temperature of 85° C. in the same manner as the upper belt.

[0026] <Cleaning unit> Next, we will discuss the cleaning unit.

[0027] 1 will be described. The cleaning unit 60 for cleaning the inner surface of the fixing belt is disposed inside the upper belt unit 20, and the cleaning unit 80 for cleaning the surface of the fixing belt is disposed outside the upper belt unit 20.

[0028] The cleaning units 60 and 80 are cleaning mechanisms that remove dirt adhering to the inner surface of the upper belt 21 .

[0029] Since the upper belt 21 rotates in contact with each roller, there is a possibility that dust from the belt, dust from the rollers, and foreign matter may be generated from the contact areas between the inner surface of the upper belt 21 and each roller.

[0030] In addition, the roller is provided with a rubber layer, which contains plasticizers, vulcanizing agents, release agents, low molecular weight components, etc., and these components bleed out and adhere to the roller surface when used for a long time, affecting the coefficient of friction with the inner surface of the upper belt 21. As a result, the upper belt 21 may slip.

[0031] To prevent such slippage, a cleaning unit 60 is provided.

[0032] The cleaning unit 80 is provided to remove ink components, paper powder, etc. adhering to the upper belt and to prevent them from adhering again to the paper.

[0033] The cleaning units 60, 80 have cleaning webs 61, 81.

[0034] The bleeding components adhering to the inner surface of the upper belt are removed by the cleaning web 61. The cleaning web 61 made of nonwoven fabric or the like contacts the upper belt via a web roller 63. The cleaning web 61 is made of nonwoven fabric or the like woven with aramid fibers or the like, and is impregnated with a lubricant to reduce the coefficient of friction between the upper belt 21 and each roller. Silicone oil is preferably used as the oil impregnated in the web from the viewpoint of heat resistance and the like. Among them, oils of various viscosities are used depending on the conditions of use, but oils with too high a viscosity have poor fluidity when applied. Therefore, oils of 30,000 cSt or less are usually used. Specific examples of such oils include dimethyl silicone oil, amino-modified silicone oil, fluorine-modified silicone oil, etc., but are not limited to these.

[0035] The cleaning web is 50 μm thick, and the thickness and density are selected depending on the object to be cleaned.

[0036] The cleaning web 80 may be impregnated with a lubricant to efficiently clean foreign matter such as ink components and paper powder adhering to the upper belt surface, but it does not have to be impregnated with a lubricant in order to prevent oil streaks from appearing on the image due to the lubricant.

[0037] Since the cleaning web 61 is impregnated with a lubricant, when the lubricant is heated, the components of the lubricant become ultra-fine particles (UFP) with particle sizes of several to several hundred nm, which can float within the main body of the apparatus.

[0038] When UFPs become airborne inside a device, they adhere to various components, which can cause the recording material to become dirty, reducing the quality of the finished product and changing the coefficient of friction between various parts.

[0039] For this reason, the cleaning web 61 is placed in a location just past the tension roller 23 where the temperature of the inner surface of the upper belt is lower. The temperature of the inner surface of the upper belt is lowered as heat is lost each time it passes through the rollers 22 and 23 in contact with it. For this reason, by placing the cleaning web in the above position, the generation of UFPs is minimized. Even with the current placement, there is no problem with the cleaning ability of the cleaning web.

[0040] Further, the cleaning units 60 and 80 are provided with a contact / separation mechanism that enables the web rollers 63 and 83 to contact and separate from the fixing belt.

[0041] The cleaning webs 61, 81 are consumables. Once the cleaning webs 61, 81 have had impurities such as bleed components collected, they are taken up by the web take-up rollers 65, 85, so that a fresh surface of the web is always in contact with the upper belt.

[0042] When the cleaning web 61, 81 delivered from the web delivery roller 64, 84 runs short, the cleaning web 61, 81 must be replaced with a new one.

[0043] In the above embodiment, the cleaning device is disposed on the upper belt side, but since the lower belt also gets dirty on both its inner and outer surfaces, the cleaning device may be disposed on the lower belt side. Also, cleaning devices may be disposed on both the upper and lower belts. EXAMPLES

[0044] 2 is a diagram illustrating a cleaning unit 60 and a cleaning unit 80 according to a second embodiment. The cleaning unit 60 is disposed inside the upper belt unit 20.

[0045] Explanation of the parts common to the first embodiment will be omitted. The difference from the first embodiment is that the cleaning unit 60 on the inner surface (21) of the upper belt is a scraper 66 instead of a cleaning web. This is because the scraper 66 can be implemented at a lower cost than the cleaning web. The scraper 66 is composed of a highly rigid metal part that supports the scraper, and an elastic member to improve cleaning performance.

[0046] The cleaning unit 60 has a scraper 66 for removing foreign matter on the inner surface of the upper belt, and a foreign matter collector 67 for collecting the foreign matter. The foreign matter collector 67 is periodically cleaned to prevent the inside of the device from becoming dirty.

[0047] In this embodiment as well, the scraper 66 is disposed opposite the web roller 83 of the cleaning unit 80 on the upper belt surface so that the cleaning unit 60 can efficiently clean the inner surface of the upper belt, and the scraper 66 can contact the inner surface of the upper belt with a predetermined pressure. Specifically, the scraper 66 is designed to have a corner located at the contact point between the web roller 83 and the upper belt. Also, in order to improve cleaning performance, the scraper 66 is disposed so as to be counter to the rotation direction of the upper belt. Specifically, it is disposed at a 45 degree angle with respect to the belt surface (horizontal plane). Comparative Example 1

[0048] 3 shows a fixing device 100 in which there are no cleaning units in the upper belt unit 20 and the lower belt unit 30. Comparative Example 1 is the same as Example 1 except that there is no cleaning unit.

[0049] <Evaluation of upper and lower belt speed difference during durability> A durability test was carried out using the fixing devices of the embodiment and the comparative example.

[0050] Each fixing device was placed in an idling test machine, and the fixing temperature was set to 100°C, the process speed to 700mm / sec, and the speeds of the upper belt 21 and the lower belt 31 were measured every 100 hours using a laser Doppler velocimeter (Canon LV-20Z) to compare the speed differences between the upper belt and the lower belt. Measurements were performed five times for each belt, the average of the measurement results was taken as the belt speed, and the speed differences between the upper belt and the lower belt were compared in absolute values.

[0051] In Examples 1 and 2, cleaning was performed every 20 hours of continuous rotation. The cleaning performed every 20 hours was performed when paper was passed through or while the fixing device was in operation. The cleaning was performed by operating the contact mechanism of the web roller to bring the cleaning web into contact with the roller, with a cleaning web feed speed of 1 mm / sec and a cleaning time of 60 sec. After cleaning, the separation mechanism of the web roller was operated to separate the cleaning web. Cleaning device 80, which cleans the surface of the upper belt, and cleaning device 60, which cleans the inner surface of the upper belt, perform cleaning operations simultaneously. The cleaning settings for both 60 and 80 are the same as above.

[0052] In the second embodiment, the cleaning device 60 for the inner surface of the upper belt is a scraper, so there is no attachment / detachment operation and the device is in a constant cleaning state.

[0053] In Comparative Example 1, no cleaning process was performed because there was no cleaning mechanism.

[0054] The durability test results are shown in Table 1. [Table 1]

[0055] <Evaluation of paper wrinkles> The fixing device that had been subjected to the durability test, that is, the fixing device after the durability test of 1200 hours, was used to evaluate the occurrence of wrinkles on the paper.

[0056] In an environment of high temperature (about 30°C) and high humidity (about 80%), the fixing temperature was set to 100°C, the process speed was set to 700 mm / sec, and SRA3 size paper (product name "OK Prince Johyo 52", manufactured by Oji Paper Co., Ltd.) was used as the evaluation paper. 100 sheets were continuously passed through, and the number of sheets with paper wrinkles was compared.

[0057] The results of the paper wrinkle evaluation test are shown in Table 2. [Table 2]

[0058] <Evaluation Results> In Examples 1 and 2, the speed difference between the upper and lower belts was 0.2 mm / sec or less, and the number of sheets with wrinkles was 0. In addition, there was no noticeable dirt on the inner surface and surface of the upper belt 21.

[0059] In Comparative Example 1, the upper and lower belts had a speed difference of 0.5 mm / sec or more after 600 hours, and the difference was about 2 mm / sec at 1200 hours. In the state of the fixing unit after 1200 hours of durability, the occurrence of wrinkles on 21 sheets of paper was confirmed.

[0060] In other words, if the speed difference between the upper and lower belts during durability testing was 2.0 mm / s or more, paper wrinkles were more likely to occur, and if the speed difference between the upper and lower belts was 0.2 mm / s or less, no wrinkles occurred in the paper.

[0061] On the inner surface of the upper belt 21 of Comparative Example 1, stains that had bled from the rubber layers of the drive rollers 22 and 32 and wear powder from the rubber layers of the drive rollers 22 and 32 were visually observed.

[0062] In addition, since the front surface of the upper belt is likely to be particularly soiled with recording material and ink, the cleaning means may be driven more frequently on the front surface of the upper belt than on the rear surface of the upper belt. The diameters of the cleaning webs of the cleaning members 60 and 80 may be the same or different.

[0063] In the above embodiment, the cleaning device is disposed on the upper belt side, but since the lower belt and its inner surface also become dirty as shown in Fig. 4, the cleaning device may be disposed on the lower belt side. Also, cleaning devices may be disposed on both the upper belt and the lower belt as shown in Fig. 5. Also, the belt inner surface cleaning member may be in the shape of a scraper. EXAMPLES

[0064] The fixing device is a block diagram of an inkjet recording apparatus that dries and fixes ink printed on a recording material by an inkjet method.

[0065] <Fixing device> The fixing device 100 is composed of an upper belt unit 20 and a lower belt unit 30, and a nip N is formed by pressing the upper and lower belts together.

[0066] The upper belt 21 is stretched around three rollers, an upper driving roller 22, an upper tension roller 23, and an upper steering roller 24. Similarly, the lower belt 31 is stretched around three rollers, a lower driving roller 32, a lower tension roller 33, and a lower steering roller .

[0067] The three rollers are common to the upper and lower units, and the tension roller and steering roller are metal rollers with an outer diameter of 50 mm and a thickness of 10 mm. They can be made of iron or aluminum. In this embodiment, aluminum metal rollers are used.

[0068] The upper and lower drive rollers 22, 32 are metal rollers with a rubber layer on the outside, which gives them a higher coefficient of friction with the inner surface of the belt than the other rollers. In this embodiment, a 5 mm thick rubber layer is provided on the outer periphery of an aluminum roller with an outer diameter of 40 mm. The type of rubber that can be used includes urethane rubber and silicone rubber. In this embodiment, urethane rubber is used.

[0069] When a motor (not shown) applies torque to the drive rollers, the upper belt 21 and the lower belt 22 rotate. The recording material S with an unfixed image thereon is transported in the direction of the arrow. By performing a long nip and heating with both the upper belt and the lower belt, the ink applied to the recording material S penetrates into the paper, achieving high print quality.

[0070] <Heating source> The heater 40 is a heat source disposed in the upper unit, and the side opposite the nip is covered by a reflector 41. The heater 40 can quickly apply heat to the image surface of the recording material S by directly heating the nip portion of the upper belt 21. The heater can be a halogen heater or a carbon heater. In this embodiment, a halogen heater is used. Since the heater 40 directly heats the belt, it has good thermal response, and by switching the output when switching the paper type, the fixing operation can be continued without waiting time.

[0071] The lower belt unit 30 is stretched around three rollers. The heater 42 is a halogen heater disposed in the lower steering roller 34. The lower belt 31 is heated by the lower steering roller 34 heated by the heater 42. The lower belt unit 30 can also directly heat the lower belt 31 with a halogen heater like the upper belt unit 20, but since the lower belt unit does not heat the image surface of the recording material S, it does not require a thermal response like the upper belt unit, and therefore a halogen heater in the steering roller is used as the heating source.

[0072] The upper belt and the lower belt form a nip N, which heats the ink and the recording material S. The ink applied to the recording material S permeates into the recording material S, and the image is fixed to the recording material S.

[0073] <Cleaning unit> Next, we will discuss the cleaning unit.

[0074] 7 is a diagram illustrating the cleaning unit 60 and the cleaning unit 70 of the embodiment 3. The cleaning unit 60 is disposed inside the upper belt unit 20, and the cleaning unit 70 is disposed inside the lower belt unit 30.

[0075] The cleaning units 60, 70 are cleaning mechanisms that remove dirt adhering to the surfaces of the drive rollers 22, 32. The drive rollers are provided with a rubber layer, which contains plasticizers, vulcanizing agents, release agents, low molecular weight components, etc., and when used for a long period of time, these components bleed out and adhere to the roller surface, affecting the coefficient of friction with the upper belt 21 or lower belt 31. As a result, the upper belt 21 or lower belt 31 may slip.

[0076] In order to prevent such slippage, the cleaning units 60, 70 are provided. The cleaning units 60, 70 each include a collection roller 62, 72 and a cleaning web 61, 71.

[0077] The recovery rollers 62, 72 are rotated by contacting the surfaces of the drive rollers 22, 32. The surfaces of the recovery rollers 62, 72 are lipophilic and have higher lipophilicity than the surfaces of the drive rollers 22, 32. Therefore, the recovery rollers 62, 72 recover the bleed components.

[0078] The bleed components collected by the collection rollers 62, 72 are removed from the collection rollers 62, 72 by the cleaning webs 61, 71. Web rollers 63, 73 come into contact with the collection rollers 62, 72 via the cleaning webs 61, 71 made of nonwoven fabric or the like. Since the collection rollers 62, 72 are rotated by the drive rollers 22, 32, the bleed components adhering to the collection roller surfaces 62, 72 are removed from the collection rollers 62, 72 by the cleaning webs 61, 71.

[0079] The cleaning units 60, 70 also include a contact / separation mechanism that allows the web rollers 63, 73 to contact and separate from the collection rollers 62, 72. The cleaning webs 61, 71 are consumables. Once the cleaning webs 61, 71 have been used to collect bleed components, they are wound up by the web take-up rollers 65, 75, and when the cleaning webs 61, 71 sent out from the web sending-out rollers 64, 74 run short, they must be replaced with new cleaning webs 61, 71. It is therefore desirable to prevent the cleaning webs 61, 71 from being wasted as much as possible. For this reason, the cleaning units perform control to bring the collection rollers 62, 72 into contact with the surfaces of the drive rollers 22, 32, and to bring the collection rollers 62, 72 into contact with the cleaning webs 61, 71. EXAMPLES

[0080] 8 is a diagram illustrating the cleaning unit 60 and the cleaning unit 70 of the fourth embodiment. The cleaning unit 60 is disposed inside the upper belt unit 20, and the cleaning unit 70 is disposed inside the lower belt unit 30.

[0081] The difference from Example 3 is that there are no recovery rollers 62, 72, and the upper and lower drive rollers 22, 32 are metal rollers with a rubber layer on the outside, but the material used is less prone to bleeding than the rubber in Example 3. Hard silicone rubber is used in this example. Hard silicone rubber is less prone to bleeding, but because it is hard, wear powder adheres to the inner surface of the upper belt 21 or lower belt 31 after long-term use, which can cause the upper belt 21 or lower belt 31 to slip.

[0082] In order to prevent such slippage, cleaning units 60 and 70 are provided. In the cleaning units 60 and 70, the cleaning web 61 can come into contact with the upper tension roller 23, and the cleaning web 71 can come into contact with the lower tension roller 33.

[0083] Wear powder adhering to the inner surface of the upper belt 21 or the inner surface of the lower belt 31 is also carried to the upper tension roller 23 which is in contact with the inner surface of the upper belt 21. Similarly, it is also carried to the lower tension roller 33 which is in contact with the inner surface of the lower belt 31. Web rollers 63, 73 abut against the tension rollers 23, 33 via cleaning webs 61, 71 made of nonwoven fabric or the like. Since the tension rollers 23, 33 are rotated by the belts 21, 31, wear powder adhering to the surfaces of the tension rollers 23, 33 is removed from the tension rollers 23, 33 by the cleaning webs 61, 71. Comparative Example 2

[0084] 9 shows a fixing device 10 in which the upper belt unit 20 and the lower belt unit 30 do not have cleaning units. Comparative Example 3 is the same as Example 3 except that there is no cleaning unit. Comparative Example 3

[0085] Comparative Example 3 is the same as Example 4, except that there is no cleaning unit.

[0086] <Evaluation of upper and lower belt speed difference during durability> A durability test was carried out using the fixing devices of the embodiment and the comparative example.

[0087] Each fixing device was placed in an idling test machine, and the fixing temperature was set to 100°C, the process speed to 700mm / sec, and the speeds of the upper belt 21 and the lower belt 31 were measured every 100 hours using a laser Doppler velocimeter (Canon LV-20Z) to compare the speed differences between the upper belt and the lower belt. Measurements were performed five times for each belt, the average of the measurement results was taken as the belt speed, and the speed differences between the upper belt and the lower belt were compared in absolute values.

[0088] In Examples 3 and 4, cleaning was performed every 20 hours of continuous rotation. However, when belt speed was measured every 100 hours, cleaning was performed after the speed measurement was completed. The cleaning was performed by bringing the cleaning web into contact with the recovery roller or tension roller using the web roller contact mechanism, with a process speed of 350 mm / sec, a cleaning web feed speed of 1 mm / sec, and a cleaning time of 60 sec. After cleaning, the cleaning web was separated by operating the web roller separation mechanism.

[0089] In Comparative Example 2 and Comparative Example 3, cleaning processing was not performed because there was no cleaning mechanism. However, similar to Example 3 and Example 4, the process speed was changed every 20 hours of continuous rotation time to prevent any difference in the belt running distance between the Examples and Comparative Examples.

[0090] The durability test results are shown in Table 3. [Table 3]

[0091] <Evaluation of paper wrinkles> The fixing device that had been subjected to the durability test was used to evaluate whether or not wrinkles occurred on the paper.

[0092] In an environment of high temperature (about 30°C) and high humidity (about 80%), the fixing temperature was set to 100°C, the process speed was set to 700 mm / sec, and SRA3 size paper (product name "OK Prince Johyo 52", manufactured by Oji Paper Co., Ltd.) was used as the evaluation paper. 100 sheets were continuously passed through, and the number of sheets with paper wrinkles was compared.

[0093] The results of the paper wrinkle evaluation test are shown in Table 4. [Table 4]

[0094] <Evaluation Results> In Examples 3 and 4, there was almost no difference in speed between the upper and lower belts, and the number of sheets with wrinkles was 0. In addition, there was no noticeable dirt on the inner surface of the upper belt 21 or the inner surface of the lower belt 31.

[0095] In Comparative Example 2 and Comparative Example 3, the difference between the upper and lower belts was observed after more than 600 hours, and the difference was about 2 mm / sec at 1200 hours. The occurrence of paper wrinkles was confirmed. Dirt that had bled from the rubber layers of the drive rollers 22 and 32 was visually confirmed on the inner surface of the upper belt 21 and the inner surface of the lower belt 31 in Comparative Example 2. Adhesion of wear powder from the rubber layers of the drive rollers 22 and 32 was visually confirmed on the inner surface of the upper belt 21 and the inner surface of the lower belt 31 in Comparative Example 3.

[0096] In this way, the embodiment can provide a long-life image heating device that prevents dirt from adhering to the inner surface of the belt by performing regular cleaning processing, can drive the belt stably for a long period of time compared to the comparative example, and suppresses the occurrence of paper wrinkles.

[0097] In this way, the embodiment can provide a long-life image heating device that prevents dirt from adhering to the inner surface of the belt by performing periodic cleaning processing, can drive the belt stably for a long period of time compared to the comparative example, and suppresses the occurrence of paper wrinkles. [Explanation of symbols]

[0098] 100 Fixing device 20 Upper belt unit 21 Upper Belt 22 Upper drive roller 23 Upper tension roller 24 Upper steering roller 30 Lower belt unit 31 Lower Belt 32 Lower drive roller 33 Lower tension roller 34 Lower steering roller 40 Upper belt heater 41 Reflector 42 Lower belt heater 50 Upper belt temperature sensor 51 Lower belt temperature sensor 60, 70, 80 cleaning units 61, 71, 81 Cleaning Web 62, 72 Collection roller 63, 73, 83 Web Roller 64, 74, 84 Web feed roller 65, 75, 85 Web take-up roller 66 Scraper 67 Recovery Device

Claims

1. In an image forming apparatus for fixing an image on a recording material, A fixing device comprising an outer surface cleaning unit for cleaning an outer surface of a fixing member, and an inner surface cleaning unit for cleaning an inner surface of the fixing member, the outer surface cleaning unit and the inner surface cleaning unit facing each other across the fixing member.

2. A fixing device including an upper belt unit including an upper belt and at least two rollers for tensioning the upper belt, and a lower belt unit including a lower belt and at least two rollers for tensioning the lower belt, 2. The fixing device according to claim 1, further comprising a cleaning unit disposed inside or outside at least one of the upper belt unit and the lower belt unit.

3. The fixing device according to claim 1 or 2, characterized in that there are three or more members for tensioning the fixing member, the tension members being counted from the exit side of the fixing nip as a first tension member and a second tension member, and the cleaning unit is positioned between the second tension member and the entrance of the fixing nip.

4. 4. The fixing device according to claim 1, wherein the cleaning unit is configured with a web member as a dirt collecting member.

5. 5. The fixing device according to claim 1, wherein the cleaning unit for cleaning the inner surface of the fixing member is in the form of a scraper or a blade.

6. A fixing device including an upper belt unit including an upper belt and at least two rollers for tensioning the upper belt, and a lower belt unit including a lower belt and at least two rollers for tensioning the upper belt, A fixing device, comprising: a cleaning unit disposed inside at least one of the upper belt unit and the lower belt unit, for cleaning a member that transports the belt.

7. 7. The fixing device according to claim 6, wherein the cleaning unit is disposed on a driving member of the belt.

8. 8. The fixing device according to claim 6, wherein the cleaning unit is configured with a web member as a dirt collecting member.

9. In a configuration having at least one of an upper collection roller that is rotated by an upper drive roller that drives the upper belt and a lower collection roller that is rotated by a lower drive roller that drives the lower belt, and having a web roller that contacts the upper collection roller or the lower collection roller, or both, via a web member, 9. The fixing device according to claim 6, wherein at least one or both of the collection rollers and at least one or both of the web rollers have a lower peripheral speed than the one or both of the web rollers.

10. In a configuration having at least one of an upper tension roller for tensioning the upper belt and an upper tension roller for tensioning the lower belt, and a web roller that contacts the one or both of the tension rollers via a web member, 9. The fixing device according to claim 6, wherein at least one or both of the tension rollers and at least one or both of the web rollers have a slower peripheral speed than at least one or both of the web rollers.

Images