Fixing device and image forming apparatus

Abstract

To provide a fixing device that can provide a stable image without the occurrence of glossiness memory without imposing a burden on a user, and an image forming apparatus including the fixing device.SOLUTION: A fixing device comprises: a fixing member (fixing belt 162) that thermally fixes a toner image transferred to a sheet to the sheet; and a plurality of first cleaning members (upstream side cleaning roller 165A, downstream side cleaning roller 165B) that are in contact with the fixing member and clean the fixing member. The plurality of first cleaning members are different in releasability of a surface layer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, electrophotographic image forming devices have been known that form an image on paper by developing an electrostatic latent image formed on a photosensitive member with toner to form a toner image, transferring the formed toner image to paper, and heat-fixing the transferred toner image.

[0003] In the image forming apparatus described above, wax seeps out from the toner during fixing by the fixing unit and adheres to the fixing belt. When the fixing belt comes into contact with the image surface on the next rotation, the fixing state differs between the areas where the wax has adhered and the areas where it has not, resulting in unevenness in the image (gloss memory). To address this issue, the occurrence of gloss memory can be suppressed by pressing a cleaning roller (CL roller) against the fixing belt to remove the wax from the fixing belt.

[0004] In the above configuration, if a jam occurs in the fixing unit, the toner on the paper will be transferred to the fixing belt after the jam is cleared. Furthermore, the toner carried by the fixing belt will be transferred to the CL roller, significantly reducing the efficiency of wax removal from the CL roller. Therefore, when a jam occurs, a cleaning mode is executed, and a method is known in which the CL roller is cleaned with a web until the toner adhering to the CL roller is removed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-43408 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the configuration described in Patent Document 1, the release properties of the CL roller are reduced to allow for cleaning of the wax on the fixing belt, resulting in toner adhesion to the CL roller. While a certain degree of toner adhesion to the CL roller is acceptable if the goal is to remove toner from the fixing belt, if the goal is to remove wax from the fixing belt, wax seeps out from the toner adhering to the CL roller, requiring a greater amount of toner to be removed from the CL roller, which requires a significant amount of time to execute the cleaning mode. Since image output is disabled during cleaning mode operation, the significant time required to execute the cleaning mode poses problems such as prolonged waiting times for users.

[0007] An object of the present invention is to provide a fixing device capable of providing stable images free from gloss memory without imposing a burden on the user, and an image forming apparatus equipped with the fixing device. [Means for solving the problem]

[0008] The invention described in claim 1 has been made to achieve the above object, In the fixing device, a fixing member that fixes the toner image transferred onto the paper sheet by heat; a plurality of first cleaning members that come into contact with the fixing member and clean the fixing member; Equipped with The plurality of first cleaning members have surface layers with different releasability. the law of nature, Among the plurality of first cleaning members, the first cleaning member located at the most downstream side in the rotation direction of the fixing member has lower releasability than the other first cleaning members and has a contact angle with pure water of 80 to 90 degrees. It is characterized by the following. The invention described in claim 2 has been made to achieve the above object, In the fixing device, a fixing member that fixes the toner image transferred onto the paper sheet by heat; a plurality of first cleaning members that come into contact with the fixing member and clean the fixing member; Equipped with the plurality of first cleaning members have surface layers with different releasability, Among the plurality of first cleaning members, the first cleaning member located most downstream in the rotation direction of the fixing member is characterized in that the surface roughness of the surface layer is smaller than that of the other first cleaning members.

[0012] Claim 3 The invention described in claim 2 In the fixing device described in Among the plurality of first cleaning members, the first cleaning member located most downstream in the rotation direction of the fixing member has a surface roughness of a surface layer Ra of 0.2 μm or less.

[0013] The invention described in claim 4 has been made to achieve the above object, In the fixing device, a fixing member that fixes the toner image transferred onto the paper sheet by heat; a plurality of first cleaning members that come into contact with the fixing member and clean the fixing member; a second cleaning member that cleans the first cleaning member; Equipped with The plurality of first cleaning members are cleaning rollers, and the surface layers thereof have different releasability. the law of nature, the second cleaning member is a web; a pressing member that presses the web against the cleaning roller; It is characterized by the following.

[0014] Claim 5 The invention described in claim 4 In the fixing device described in the pressing members are provided in the same number as the cleaning rollers and are arranged to face the cleaning rollers one-to-one; The web is wound around a main winding roller, and is arranged so that the web passes through a nip formed by the cleaning roller and the pressing member, and is then wound around a take-up roller.

[0015] Claim 6 The invention described in claim 5 In the fixing device described in The cleaning roller is cleaned by moving the web from the cleaning roller side on the downstream side in the rotation direction of the fixing member to the cleaning roller side on the upstream side in the rotation direction of the fixing member.

[0016] Claim 7 The invention described in claim 6 In the fixing device described in Among the plurality of pressing members, the pressing member facing the cleaning roller at the most downstream position in the rotation direction of the fixing member is characterized by having a higher pressing force for pressing the web against the cleaning roller than the other pressing members.

[0017] Claim 8 The invention described in claim 4 In the fixing device described in the plurality of first cleaning members are two cleaning rollers, One of the pressing members is arranged to press the web against the two cleaning rollers, The web wound around the original winding roller is arranged so that it passes through a nip formed by the two cleaning rollers and the one pressing member, and then is wound around a take-up roller.

[0018] Claim 9 The invention described in claim 8 In the fixing device described in The two cleaning rollers are cleaned by moving the web from the cleaning roller on the downstream side in the rotation direction of the fixing member to the cleaning roller on the upstream side in the rotation direction of the fixing member.

[0019] Claim 10 The invention described in claim 9 In the fixing device described in The one pressing member is characterized in that it applies a higher pressing force to the web to the cleaning roller downstream in the rotation direction of the fixing member than to the cleaning roller upstream in the rotation direction of the fixing member.

[0020] Claim 11 The invention described in In the image forming apparatus, an image forming unit that forms a toner image on a sheet; The toner image formed by the image forming unit is fixed onto the paper. 10 a fixing device according to any one of the preceding claims; The present invention is characterized by comprising: [Effects of the Invention]

[0021] According to the present invention, stable images free from gloss memory can be provided without imposing a burden on the user. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a front view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention; [Figure 2] FIG. 2 is a functional block diagram showing a control structure of the image forming apparatus according to the present embodiment. [Figure 3] FIG. 2 is a diagram illustrating the configuration of a fixing unit. [Figure 4] 10 is a diagram illustrating the configuration of a fixing unit according to Modification 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0024] Image forming apparatus 100 according to this embodiment is a tandem color image forming apparatus that reads an image from an original and forms (prints) the read image on paper. Image forming apparatus 100 also receives a print job containing print data and print setting information in PDL (Page Description Language) format from an external client terminal via a network, and forms an image on paper based on this. The client terminal may be, for example, a PC, a tablet terminal, or a smartphone.

[0025] 1 and 2, image forming apparatus 100 is configured to include an image reading unit 110, an image processing unit 120, an image forming unit 130, a paper feeding unit 140, a paper conveying unit 150, a fixing unit (fixing device) 160, a communication unit 180, an operation display unit 190, and a control unit 200. These components are connected to each other via an internal bus 210 so that they can communicate with each other.

[0026] The image reading unit 110 reads an original document and outputs an image information signal. An original document placed on an original table 112 is scanned and exposed by the optical system of the scanning exposure device of the image reading device 111, and the image is read into a line image sensor. The photoelectrically converted image information signal undergoes analog processing, A / D conversion, shading correction, image compression processing, etc. in the image processing unit 120, and is then input as print image data to optical writing units 3Y, 3M, 3C, and 3K of the image forming unit 130.

[0027] The image forming unit 130 forms an image (toner image) on paper based on print image data using a well-known imaging process such as electrophotography, which includes the steps of charging, exposing, developing, and transferring. The image forming unit 130 has four sets of sub-units 13Y, 13M, 13C, and 13K that form images of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

[0028] Subunit 13Y is configured with photosensitive drum 1Y, charging unit 2Y arranged around the photosensitive drum 1Y, optical writing unit 3Y, developing device 4Y, and drum cleaner 5Y. Similarly, other subunits 13M, 13C, and 13K are configured with photosensitive drums 1M, 1C, and 1K, charging units 2M, 2C, and 2K arranged around the photosensitive drums, optical writing units 3M, 3C, and 3K, developing devices 4M, 4C, and 4K, and drum cleaners 5M, 5C, and 5K, respectively. Because each of subunits 13Y, 13M, 13C, and 13K has a common configuration, they will be referred to without the symbols Y, M, C, and K unless a distinction is particularly necessary.

[0029] The image forming unit 130 writes print image data onto the photosensitive drum 1 using the optical writing unit 3, and forms a latent image based on the print image data on the photosensitive drum 1. The latent image is then developed by the developing device 4, and a toner image, which is a visible image, is formed on the photosensitive drum 1. The developing device 4 uses toner that contains (encloses) wax made of paraffin or polyolefin as a release agent.

[0030] Yellow (Y), magenta (M), cyan (C), and black (K) images are formed on the photosensitive drums 1Y, 1M, 1C, and 1K of the subunits 13Y, 13M, 13C, and 13K, respectively.

[0031] The intermediate transfer belt 6 is wound around a plurality of rollers and supported so as to be movable. The toner images of each color formed by the subunits 13Y, 13M, 13C, and 13K are successively transferred onto the moving intermediate transfer belt 6 by primary transfer units 7Y, 7M, 7C, and 7K, forming a color image in which the color layers of Y (yellow), M (magenta), C (cyan), and K (black) are superimposed.

[0032] The paper feed unit 140 supplies paper 301 as a recording material to the image forming unit 130. The paper feed unit 140 has an upper tray 141, a middle tray 142, and a lower tray 143, and each tray stores paper of different sizes, such as A4 size and A3 size.

[0033] The paper transport unit 150 transports the paper 301. The paper 301 supplied from the upper tray 141, the middle tray 142, or the lower tray 143 passes through the registration rollers 151 and is transported to the secondary transfer unit 7A, where the color image on the intermediate transfer belt 6 is transferred onto the paper 301.

[0034] The paper transport section 150 also includes a paper inversion section 152, which guides the fixed paper 301 to the paper inversion section 152, where it is inverted and discharged, or allows images to be formed on both sides of the paper 301.

[0035] The fixing unit 160 fixes the toner image formed on the paper 301. The paper 301 on which the color image has been fixed is discharged to the outside of the image forming apparatus 100 through the paper discharge unit 153.

[0036] The communication unit 180 connects to a client terminal such as a PC via a network, and transmits and receives data such as print jobs.

[0037] The operation display unit 190 has an input unit and an output unit. The input unit includes, for example, a keyboard and a touch panel, and is used by the user to input characters, various settings, print instructions, and other instructions (inputs). The output unit includes a display, and is used to present the user with information such as the device configuration, the status of print jobs, and the occurrence of errors in paper transport (e.g., jams).

[0038] The control unit 200 controls the image reading unit 110, the image processing unit 120, the image forming unit 130, the paper feeding unit 140, the paper conveying unit 150, the fixing unit 160, the communication unit 180, and the operation display unit 190. The control unit 200 has a CPU 201, an auxiliary storage device 202, a RAM 203, and a ROM 204.

[0039] The CPU 201 executes a control program for the image forming apparatus. The control program is stored in an auxiliary storage device 202, and when executed by the CPU 201, it is loaded into a RAM 203. The auxiliary storage device 202 includes a large-capacity storage device such as a hard disk drive or flash memory. The RAM 203 stores the results of calculations performed by the CPU 201. The ROM 204 stores various parameters, programs, and the like. The CPU 201 executes the control program to realize various functions.

[0040] <Configuration of Fixing Unit 160> Next, a specific configuration of the fixing unit 160 will be described with reference to Fig. 3. Fig. 3 is a schematic diagram illustrating the configuration of the fixing unit 160 shown in Fig. 1.

[0041] As shown in Figures 1 to 3, the fixing section 160 has a heating roller 161, a fixing belt 162, a fixing roller 163, a pressure roller 164, a cleaning roller 165, a cleaning drive mechanism 166 (see Figure 2), a web 167, a main winding roller 168, a winding roller 169, a pressure roller 170, and a pressure drive mechanism 171 (see Figure 2).

[0042] The heating roller 161 is, for example, a cylindrical core metal made of a metal such as aluminum, or the outer circumferential surface of which is coated with a fluorine-based resin, etc. The heating roller 161 has a built-in heater (for example, a halogen heater) H1 that heats the fixing belt 162.

[0043] The fixing belt 162 is, for example, a 70 μm-thick PI (polyimide) base whose outer peripheral surface is covered with an elastic layer, and whose surface layer is further covered with a heat-resistant resin. The elastic layer is, for example, a 200 μm-thick heat-resistant silicone rubber (hardness JIS-A30°) and the heat-resistant resin is, for example, a 30 μm-thick PFA (perfluoroalkoxy). The fixing belt 162 is endless and is stretched between the heating roller 161 and the fixing roller 163 with a predetermined belt tension (for example, 250 N).

[0044] The fixing belt 162 functions as a fixing member of the present invention that fixes the toner image transferred onto the paper 301 to the paper 301 by heat, and comes into contact with the paper 301 on which the toner image has been formed, heating the paper 301 to a fixing temperature. Here, the fixing temperature is a temperature (for example, 160 to 200°C) that can supply the amount of heat required to melt the toner on the paper 301, and differs depending on the type of paper 301 on which the image is formed. The surface temperature of the fixing belt 162 is detected by a non-contact temperature sensor (not shown), and the control unit 200 controls the heating of the heater H1 to maintain the temperature at a predetermined setting.

[0045] The fixing roller 163 includes, from the inside out, a cylindrical metal core, an elastic layer made of a material such as silicone rubber or foamed silicone rubber formed on the surface of the core, and a release layer made of a material such as fluororesin. The axial length of the fixing roller 163 is long enough to accommodate the maximum paper width that can be conveyed (e.g., 300 mm). The fixing roller 163 is driven to rotate, for example, in the R direction in FIG. 3, by power transmitted from a driving means (e.g., a motor) not shown. The peripheral speed of the fixing roller 163 is set to, for example, about 200 mm / s. The fixing belt 162 rotates following the rotation of the fixing roller 163. Therefore, the fixing roller 163 is indirectly heated by the heater H1 via the fixing belt 162.

[0046] The pressure roller 164 includes, from the inside out, a cylindrical metal core, an elastic layer formed on the surface thereof, and a release layer. The outer diameter, axial length, elastic layer, and release layer of the pressure roller 164 are the same as those of the fixing roller 163. The pressure roller 164 presses against the fixing roller 163 via the fixing belt 162 with a predetermined fixing load.

[0047] The paper 301 on which the toner image has been formed in the image forming unit 130 is transported to the fixing unit 160. The paper 301 transported from the image forming unit 130 to the fixing unit 160 is transported while being heated and pressed in the fixing nip N formed between the fixing belt 162 and the pressure roller 164, and the toner image is fixed to the paper 301.

[0048] At this time, wax may be transferred from the toner on the paper 301 on which the toner image has been fixed to the fixing belt 162, and the wax may adhere to the fixing belt 162. If the wax adhering to the fixing belt 162 adheres to the image surface of the subsequent paper being conveyed to the fixing unit 160, this may cause gloss memory (unevenness in the image) to occur in the image on the subsequent paper.

[0049] The cleaning roller 165 includes an upstream cleaning roller 165A arranged upstream in the rotation direction of the fixing belt 162, and a downstream cleaning roller 165B arranged downstream in the rotation direction of the fixing belt 162. The upstream cleaning roller 165A and the downstream cleaning roller 165B function as first cleaning members of the present invention, and come into contact with the fixing belt 162 to clean toner, wax, and the like adhering to the outer peripheral surface of the fixing belt 162. The upstream cleaning roller 165A and the downstream cleaning roller 165B have different surface release properties, with the upstream cleaning roller 165A, which has a higher release property, being arranged upstream to clean toner, and the downstream cleaning roller 165B, which has a lower release property, being arranged downstream to clean wax.

[0050] The upstream cleaning roller 165A is a cleaning roller 165 for cleaning toner, and is made by coating the outer surface of a cylindrical core made of metal such as aluminum with a fluorine-based resin (for example, PTFE (polytetrafluoroethylene)). In this embodiment, the releasability of the surfaces of the upstream cleaning roller 165A and the downstream cleaning roller 165B is determined using the contact angle with pure water (the angle of the liquid surface (tangent to the liquid surface) at the end point of a droplet of pure water, with the surfaces of the upstream cleaning roller 165A and the downstream cleaning roller 165B as the reference). The surface layer of the upstream cleaning roller 165A has a releasability (contact angle) with pure water of 90 to 110°, preferably 100 to 110°, which is equal to or slightly smaller than the releasability of the surface layer (PFA tube) of the fixing belt 162. The surface roughness of the upstream cleaning roller 165A is Ra 0.2 to 0.6 μm, and even if the surface roughness is large relative to the fixing belt 162, the toner viscosity is high, so that the cleaning effect can be obtained. The downstream cleaning roller 165B is a cleaning roller 165 for cleaning wax, and is made by coating the outer surface of a cylindrical core made of a metal such as iron or aluminum with, for example, PI (polyimide). The surface layer of the downstream cleaning roller 165B has a releasability (contact angle) with pure water of 80 to 100°, preferably 80 to 90°. To effectively clean the wax, high adhesion to the fixing belt 162 is required, and therefore the surface roughness of the surface layer of the downstream cleaning roller 165B is Ra 0.2 μm or less. In other words, the surface roughness of the surface layer of the downstream cleaning roller 165B is smaller than that of the upstream cleaning roller 165A.

[0051] The cleaning roller 165 can be moved by a cleaning drive mechanism 166 in a direction approaching (pressure contact direction) or a direction away (separation direction) from the fixing belt 162. When cleaning the fixing belt 162, the cleaning roller 165 is moved to a predetermined position close to the fixing belt 162 and is urged by an urging means such as a spring (not shown) to press against a part of the outer circumferential surface of the fixing belt 162. Furthermore, when cleaning the fixing belt 162 is not being performed, such as during standby for printing, the cleaning roller 165 can move away from the fixing belt 162 to release it from contact with the fixing belt 162. This can prevent the surface layer of the cleaning roller 165 from wearing out.

[0052] Furthermore, the rotation of the fixing roller 163 causes the fixing belt 162 to rotate, and the cleaning roller 165 also rotates in accordance with the rotation of the fixing belt 162. That is, when the cleaning roller 165 is in pressure contact with the fixing belt 162, it is driven by the rotation of the fixing roller 163 and rotates in the opposite direction to the rotation direction of the fixing roller 163. As a result, toner, wax, etc. adhering to the outer surface of the fixing belt 162 are transferred to the cleaning roller 165, and the outer peripheral surface of the fixing belt 162 is cleaned.

[0053] Web 167 functions as a second cleaning member of the present invention and removes toner, wax, and the like adhering to cleaning roller 165. Web 167 is a nonwoven fabric made of heat-resistant fibers such as aramid fibers, and is breathable. Web 167 supplied from original winding roller 168 comes into sliding contact with the outer circumferential surfaces of cleaning rollers 165 (upstream cleaning roller 165A and downstream cleaning roller 165B), is wound around pressure roller 170, and is then wound onto winding roller 169.

[0054] The take-up roller 169 is rotated little by little by a motor (not shown), and takes up the web 167. The amount of take-up is, for example, about 0.01 to 0.1 mm per printing of one A4 size sheet of paper. The main take-up roller 168 also has a braking means that constantly applies a brake to the advancement of the web 167, preventing slack from occurring during the feeding operation of the web 167.

[0055] The pressure rollers 170 are cylindrical rollers made of metal with a SUS core, and the outer circumferential surface is coated with an elastic material (such as foamed silicone rubber). The pressure rollers 170 are provided in the same number as the cleaning rollers 165 (two rollers), and are arranged so as to face the cleaning rollers 165 one-to-one. The pressure roller 170 can be moved by a pressure drive mechanism 171 in a direction approaching (pressure contact direction) or a direction away (separation direction) from the cleaning roller 165. When cleaning the cleaning roller 165, the pressure roller 170 is moved to a predetermined position close to the cleaning roller 165, and a biasing means such as a spring (not shown) presses the web 167 against the outer circumferential surface of the cleaning roller 165. In other words, the pressure roller 170 functions as a pressing member of the present invention. This brings the web 167 into pressure contact with the cleaning roller 165, and the outer circumferential surface of the rotating cleaning roller 165 is rubbed by the web 167. As a result, toner, wax, and the like adhering to the outer circumferential surface of the fixing belt 162 are taken up by the web 167, and the outer circumferential surface of the cleaning roller 165 is cleaned. Furthermore, when cleaning roller 165 is not being cleaned by web 167, such as during standby for printing, pressure roller 170 can move away from cleaning roller 165 to release contact between cleaning roller 165 and web 167. This makes it possible to prevent the toner adhering to web 167 from cooling and solidifying, which would otherwise cause web 167 to stick to cleaning roller 165, and prevents problems such as tearing of web 167 when restarting operation.

[0056] The web 167 wound around the original winding roller 168 is disposed so as to be wound around the winding roller 169 after passing through the nip formed by the cleaning roller 165 and the pressure roller 170 . Furthermore, cleaning roller 165 is cleaned by moving web 167 from the cleaning roller 165 (downstream cleaning roller 165B) side downstream in the rotation direction of fixing belt 162 to the cleaning roller 165 (upstream cleaning roller 165A) side upstream in the rotation direction of fixing belt 162. This causes cleaning by web 167 to be performed in the order of downstream cleaning roller 165B for cleaning wax and then upstream cleaning roller 165A for cleaning toner, thereby preventing toner from being transferred via web 167 to downstream cleaning roller 165B for cleaning wax. Furthermore, among the multiple pressure rollers 170, the pressure roller 170 facing the cleaning roller (downstream cleaning roller 165B) that is furthest downstream in the rotation direction of the fixing belt 162 applies a higher pressure to press the web 167 against the cleaning roller 165 than the other pressure rollers 170 (pressure rollers 170 facing the upstream cleaning roller 165A). For example, if a jam occurs and a large amount of unfixed toner adheres to the upstream cleaning roller 165A, which is used to clean the toner, via the fixing belt 162, and the toner cannot be completely removed by passing the web 167 through the nip formed by the upstream cleaning roller 165A and the pressure roller 170 just once, the toner on the upstream cleaning roller 165A will stick to the web 167, and the rotation of the upstream cleaning roller 165A will apply a force that tries to pull out more of the web 167 than necessary, which is wound around the original winding roller 168. Therefore, by setting the pressing force of the pressure roller 170 facing the cleaning roller (downstream cleaning roller 165B) at the most downstream position in the rotation direction of the fixing belt 162 to be greater than that of the other pressure rollers 170, it is possible to resist the force trying to pull out the web 167.

[0057] The control unit 200 controls the drive means for the fixing roller 163 , the heater H 1 , the cleaning drive mechanism 166 , the motor for the take-up roller 169 , and the pressure drive mechanism 171 .

[0058] In the fixing device (fixing section 160) according to this embodiment, first, the toner that has been offset onto the fixing belt 162 reaches the upstream cleaning roller 165A for cleaning the toner, and the toner is cleaned off by the upstream cleaning roller 165A. The wax contained in the toner is easy to clean when the contact angle with pure water is 100° or less, and preferably cleaning effect is enhanced by making it less than 90°. Therefore, the upstream cleaning roller 165A for cleaning toner, which has a contact angle with pure water of 100 to 110°, does not provide sufficient cleaning effect, but the downstream cleaning roller 165B for cleaning wax is sufficient to clean it. Furthermore, by providing a web 167 that is pressed against each cleaning roller 165, the toner and wax that each cleaning roller 165 has already cleaned can be removed, thereby maintaining the efficiency of cleaning the toner and wax.

[0059] As described above, the fixing device (fixing section 160) of image forming apparatus 100 according to this embodiment includes a fixing member (fixing belt 162) that heat-fixes a toner image transferred onto paper, and a plurality of first cleaning members (upstream cleaning roller 165A, downstream cleaning roller 165B) that come into contact with the fixing member and clean it. The plurality of first cleaning members have surface layers with different releasability. Therefore, according to the fixing device of this embodiment, by cleaning the toner with the first cleaning member (upstream cleaning roller 165A) with high releasability, it is possible to clean the toner that has offset onto the fixing belt 162, thereby preventing the first cleaning member (downstream cleaning roller 165B) with low releasability from being contaminated by toner. This eliminates the need to provide a cleaning mode for toner cleaning, thereby reducing waiting time during the cleaning mode. Therefore, it is possible to provide stable images that do not cause gloss memory, without imposing a burden on the user.

[0060] Furthermore, in the fixing device according to this embodiment, of the plurality of first cleaning members, the first cleaning member located most downstream in the rotation direction of the fixing member has lower releasability than the other first cleaning members. Therefore, with the fixing device according to this embodiment, the toner offset onto the fixing belt 162 can be cleaned by cleaning the toner with the first cleaning member (upstream cleaning roller 165A) with high releasability located upstream, thereby preventing the first cleaning member (downstream cleaning roller 165B) with low releasability located at the most downstream side from being contaminated with toner. This eliminates the need for a cleaning mode for toner cleaning, thereby reducing waiting time during the cleaning mode. This makes it possible to provide stable images without gloss memory without imposing a burden on the user.

[0061] Furthermore, in the fixing device according to this embodiment, of the plurality of first cleaning members, the first cleaning member located most downstream in the direction of rotation of the fixing member has a contact angle with pure water of 80 to 90°. Therefore, according to the fixing device of this embodiment, the wax can be cleaned by the most downstream first cleaning member (downstream cleaning roller 165B), so that the occurrence of gloss memory can be suppressed.

[0062] Furthermore, in the fixing device according to the present embodiment, of the plurality of first cleaning members, the first cleaning member located most downstream in the rotation direction of the fixing member has a surface layer with a smaller surface roughness than the other first cleaning members. Therefore, according to the fixing device of this embodiment, the wax can be evenly cleaned by the first cleaning member (downstream cleaning roller 165B) at the most downstream position, which has a smooth surface, thereby suppressing the occurrence of uneven cleaning and gloss memory.

[0063] Furthermore, in the fixing device according to the present embodiment, of the plurality of first cleaning members, the first cleaning member located most downstream in the direction of rotation of the fixing member has a surface roughness of Ra 0.2 μm or less. Therefore, according to the fixing device of this embodiment, the wax can be evenly cleaned by the first cleaning member (downstream cleaning roller 165B) at the most downstream position, which has a smooth surface, so that uneven cleaning and the occurrence of gloss memory can be more reliably suppressed.

[0064] The fixing device according to this embodiment also includes a second cleaning member that cleans the first cleaning member. The first cleaning member is a cleaning roller (upstream cleaning roller 165A, downstream cleaning roller 165B), and the second cleaning member is a web 167. The fixing device further includes a pressing member (pressing roller 170) that presses the web 167 against the cleaning roller. Therefore, the fixing device according to this embodiment can clean the toner and wax off the cleaning roller, preventing the toner and wax from accumulating on the cleaning roller, thereby increasing the efficiency with which the cleaning roller removes toner and wax from the fixing belt 162, and stably suppressing the occurrence of gloss memory.

[0065] Furthermore, in the fixing device according to this embodiment, the pressing members (pressing rollers 170) are provided in the same number as the cleaning rollers and are arranged so as to face the cleaning rollers one-to-one, and the web 167 wound around the original winding roller 168 is arranged so as to be wound around the winding roller 169 after passing through the nip formed by the cleaning roller and the pressing members. Therefore, according to the fixing device of this embodiment, it is possible to stably suppress the occurrence of gloss memory because the cleaning roller can increase the efficiency of removing toner and wax from the fixing belt 162. Furthermore, because the cleaning roller and pressure roller 170 are easily designed, it is possible to easily suppress the occurrence of gloss memory.

[0066] Furthermore, in the fixing device according to this embodiment, the cleaning roller is cleaned by moving the web 167 from the cleaning roller on the downstream side in the rotation direction of the fixing member to the cleaning roller on the upstream side in the rotation direction of the fixing member. Therefore, in the fixing device according to this embodiment, cleaning is performed by the web 167 in the order of downstream cleaning roller 165B for cleaning wax and then upstream cleaning roller 165A for cleaning toner, thereby preventing toner from being transferred to downstream cleaning roller 165B for cleaning wax via the web 167.

[0067] Furthermore, according to the fixing device of this embodiment, among the multiple pressing members, the pressing member facing the cleaning roller at the most downstream position in the rotation direction of the fixing member has a higher pressing force for pressing the web 167 against the cleaning roller than the other pressing members. Therefore, according to the fixing device of this embodiment, even if toner on the upstream cleaning roller 165A sticks to the web 167 and a force acts to pull out the web 167 wound around the main winding roller 168 more than necessary, the force to pull out the web 167 can be resisted, so that cleaning of the cleaning roller by the web 167 and cleaning of the fixing belt 162 by the cleaning roller can be stably performed.

[0068] Although the present invention has been specifically described above based on the embodiments thereof, the present invention is not limited to the above embodiments and can be modified within the scope of the present invention.

[0069] (Variation 1) For example, in the above embodiment, the same number of pressure rollers 170 (two rollers) as the number of cleaning rollers 165 are provided, but the present invention is not limited to this. For example, as shown in Fig. 4, two cleaning rollers 165 and one pressure roller 170 may be provided, and the one pressure roller 170 may be arranged so that it presses the web 167 against the two cleaning rollers 165 simultaneously. In this case, the web 167 wound around the original winding roller 168 is arranged so that it is wound around the winding roller 169 after passing through a nip formed by the two cleaning rollers 165 and the one pressure roller 170. As described above, the multiple first cleaning members are two cleaning rollers, one pressing member (pressure roller 170) is arranged to press web 167 against the two cleaning rollers, and web 167 wound around original winding roller 168 is arranged to be wound around take-up roller 169 after passing through a nip formed by the two cleaning rollers and the one pressing member. This increases the efficiency with which the cleaning rollers remove toner and wax from fixing belt 162, thereby stably suppressing the occurrence of gloss memory. Furthermore, the number of pressure rollers 170 can be reduced, thereby reducing costs and suppressing the occurrence of gloss memory. In addition, in variant example 1, the two cleaning rollers 165 are cleaned by moving the web 167 from the cleaning roller 165 (downstream cleaning roller 165B) on the downstream side in the rotation direction of the fixing belt 162 to the cleaning roller 165 (upstream cleaning roller 165A) on the upstream side in the rotation direction of the fixing belt 162. As described above, by moving the web 167 from the cleaning roller side downstream in the rotation direction of the fixing member (downstream cleaning roller 165B) to the cleaning roller side upstream in the rotation direction of the fixing member (upstream cleaning roller 165A), the two cleaning rollers are cleaned, and cleaning is performed by the web 167 in the order of downstream cleaning roller 165B for cleaning wax and then upstream cleaning roller 165A for cleaning toner, thereby preventing toner from being transferred to the downstream cleaning roller 165B for cleaning wax via the web 167. In addition, one pressure roller 170 applies a higher pressure to press the web 167 against the cleaning roller 165 (downstream cleaning roller 165B) on the downstream side in the rotation direction of the fixing belt 162 than against the cleaning roller 165 (upstream cleaning roller 165A) on the upstream side in the rotation direction of the fixing belt 162. As described above, one pressing member applies a higher pressure to press web 167 against the cleaning roller downstream in the direction of rotation of the fixing member (downstream cleaning roller 165B) than against the cleaning roller upstream in the direction of rotation of the fixing member (upstream cleaning roller 165A). Therefore, even if toner on upstream cleaning roller 165A sticks to web 167 and a force acts to pull out web 167 wound around master winding roller 168 more than necessary, the force trying to pull out web 167 can be resisted, and cleaning of the cleaning roller by web 167 and cleaning of fixing belt 162 by the cleaning roller can be stably performed.

[0070] (Other variations) Furthermore, in the above embodiment, a configuration including two cleaning rollers 165, an upstream cleaning roller 165A with high release properties for cleaning toner and a downstream cleaning roller 165B with low release properties for cleaning wax, has been described as an example, but this is not limited thereto. That is, the cleaning roller 165 may be configured to include at least an upstream cleaning roller 165A with high release properties for cleaning toner and a downstream cleaning roller 165B with low release properties for cleaning wax. For example, in addition to the two cleaning rollers 165, one or more cleaning rollers 165 with high release properties for cleaning toner or one or more cleaning rollers 165 with low release properties for cleaning wax may be added. Furthermore, when special toners such as white toner or clear toner are used, an additional cleaning roller 165 for cleaning the special toner may be added. In this case, cleaning efficiency can be maintained by adjusting the release properties of the cleaning roller 165 for cleaning the special toner to match the physical properties of each special toner. As described above, when three or more cleaning rollers 165 are provided, it is preferable to arrange at least the downstream cleaning roller 165B, which has low releasability and is used for cleaning wax, at the most downstream position. It is also preferable to arrange all the cleaning rollers 165 for cleaning toner, including the cleaning roller 165 for cleaning special toner, on the upstream side, and all the cleaning rollers 165 for cleaning wax on the downstream side.

[0071] In the above embodiment, the cleaning drive mechanism 166 is configured to enable the upstream cleaning roller 165A and the downstream cleaning roller 165B to be brought into contact with and separated from the fixing belt 162, and the pressure drive mechanism 171 is configured to enable the web 167 to be brought into contact with and separated from each cleaning roller 165. However, even in a configuration including three or more cleaning rollers 165, all of the cleaning rollers 165 may be configured to be brought into contact with and separated from the fixing belt 162. For example, by configuring the cleaning rollers 165 and the web 167 to be independently brought into contact with and separated from each other, when special toner is not being used, the cleaning roller 165 for cleaning special toner can be separated from the fixing belt 162, and the web 167 can be separated from the cleaning roller 165 for cleaning special toner. This reduces the amount of web 167 used and extends the life of the cleaning roller 165 for cleaning special toner.

[0072] In addition, the detailed configuration and operation of each device constituting the image forming apparatus can be modified as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0073] 100 Image forming device 110 Image reading unit 111 Image reading device 112 manuscript table 120 Image processing unit 130 Image forming unit 13Y, 13M, 13C, and 13K subunits 1Y, 1M, 1C, 1K photoconductor drum 2Y, 2M, 2C, 2K charging unit 3Y, 3M, 3C, 3K optical writing section 4Y, 4M, 4C, 4K developing device 5Y, 5M, 5C, 5K drum cleaner 6 Intermediate transfer belt 7Y, 7M, 7C, 7K Primary transfer section 7A Secondary transfer section 140 Paper feed section 141 Upper tray 142 Middle Tray 143 Lower Tray 150 Paper transport unit 151 Resist Roller 152 Paper reversing unit 153 Paper output section 160 Fixing section (fixing device) 161 heated roller 162 Fixing belt (fixing member) 163 Fuser roller 164 Pressure Roller 165 Cleaning Roller 165A Upstream cleaning roller (first cleaning member) 165B downstream cleaning roller (first cleaning member) 166 Cleaning drive mechanism 167 Web (second cleaning member) 168 Original Roller 169 Winding roller 170 Pressure roller (pressure member) 171 Pressing drive mechanism 180 Communications Department 190 Operation display section 200 control section 201 CPU 202 Auxiliary storage device 203 RAM 204 ROM 210 Internal Bus 301 Paper

Claims

1. a fixing member that fixes the toner image transferred onto the paper sheet by heat; a plurality of first cleaning members that come into contact with the fixing member and clean the fixing member; Equipped with the plurality of first cleaning members have surface layers with different releasability, a first cleaning member located furthest downstream in the direction of rotation of the fixing member among the plurality of first cleaning members, the first cleaning member having a lower releasability than the other first cleaning members and a contact angle with pure water of 80 to 90 degrees.

2. a fixing member that fixes the toner image transferred onto the paper sheet by heat; a plurality of first cleaning members that come into contact with the fixing member and clean the fixing member; Equipped with the plurality of first cleaning members have surface layers with different releasability, a first cleaning member located furthest downstream in the direction of rotation of the fixing member among the plurality of first cleaning members, the first cleaning member having a surface layer with a smaller surface roughness than the other first cleaning members;

3. 3. The fixing device according to claim 2, wherein the first cleaning member located furthest downstream in the direction of rotation of the fixing member among the plurality of first cleaning members has a surface roughness of a surface layer of Ra 0.2 [mu]m or less.

4. a fixing member that fixes the toner image transferred onto the paper sheet by heat; a plurality of first cleaning members that come into contact with the fixing member and clean the fixing member; a second cleaning member that cleans the first cleaning member; Equipped with the plurality of first cleaning members are cleaning rollers, and the surface layers thereof have different releasability properties; the second cleaning member is a web; The fixing device further comprises a pressing member that presses the web against the cleaning roller.

5. the pressing members are provided in the same number as the cleaning rollers and are arranged to face the cleaning rollers one-to-one; 5. The fixing device according to claim 4, wherein the web wound around the original winding roller is arranged so as to be wound around a take-up roller after passing through a nip formed by the cleaning roller and the pressing member.

6. 6. The fixing device according to claim 5, wherein the cleaning roller is cleaned by moving the web from a side of the cleaning roller on the downstream side in the rotation direction of the fixing member to a side of the cleaning roller on the upstream side in the rotation direction of the fixing member.

7. 7. The fixing device according to claim 6, wherein, among the plurality of pressing members, the pressing member facing the cleaning roller at the most downstream position in the rotation direction of the fixing member exerts a higher pressing force for pressing the web against the cleaning roller than the other pressing members.

8. the plurality of first cleaning members are two cleaning rollers, One of the pressing members is arranged to press the web against the two cleaning rollers, 5. The fixing device according to claim 4, wherein the web wound around the original winding roller is arranged to be wound around a take-up roller after passing through a nip formed by the two cleaning rollers and the one pressing member.

9. 9. The fixing device according to claim 8, wherein the two cleaning rollers are cleaned by moving the web from the cleaning roller on the downstream side in the rotation direction of the fixing member to the cleaning roller on the upstream side in the rotation direction of the fixing member.

10. 10. The fixing device according to claim 9, wherein the one pressing member applies a higher pressing force to the web to the cleaning roller downstream in the rotation direction of the fixing member than to the cleaning roller upstream in the rotation direction of the fixing member.

11. an image forming unit that forms a toner image on a sheet; a fixing device according to any one of claims 1 to 10, which fixes the toner image formed by the image forming unit onto the paper; An image forming apparatus comprising:

Images