Fixing system and image forming apparatus

Abstract

To provide a fixing system and the like that can prevent an unnecessary object from falling on a recording medium passing through a passage part of a fixing device from a suction port of a duct of an exhaust device.SOLUTION: A fixing system 5 comprises: a fixing device 51 having a first rotating body 53 that rotates and is heated by heating means 54, and a second rotating body 55 that rotates while forming a passage part FN for passing a recording medium 9 on which a toner image is formed; and an exhaust device 60 having a fan 68A, and a duct 61A that sucks in part of air present on the outer side of the passage part FN from a suction port 611A and causes the air to flow upward at least once and subsequently causes the air to flow to be exhausted from an exhaust port 612A. The duct 61A has an opening 63 that takes in air from the outside of the duct at a position on a portion for causing the air to flow upward, a projection 64 that projects to the inside of the duct at a portion on an inner wall surface on a side facing the opening 63, and a collection part 65 that collects an unnecessary object generated and falling inside the duct at a position below the projection 64.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a fixing system and an image forming apparatus. [Background technology]

[0002] The following Patent Document 1 describes an image forming apparatus equipped with a fixing device that melts and fixes a toner image formed on a sheet of paper. Patent Document 1 also describes that the image forming apparatus is provided with an exhaust flow path that exhausts air near the fixing device to the outside of the main body of the image forming apparatus. Patent Document 1 also describes that the exhaust flow path has a first flow path, a bent portion, and a second flow path. The first flow path is a flow path that is led out of the main body and extends along one outer surface of the main body. The bent portion is a portion that bends near a corner where the one outer surface meets another outer surface that is perpendicular to the one outer surface and communicates with the first flow path. The second flow path is a flow path that communicates with the bent portion and extends along the other outer surface. Furthermore, Patent Document 1 also describes that at least an air retention portion for retaining air in the exhaust flow path is provided in the bent portion.

[0003] The following Patent Document 2 describes an image forming apparatus having an image forming unit, a transfer unit, a pair of rotating bodies, a duct, a filter, and a first fan. The image forming unit forms an image using toner containing a release agent. The transfer unit transfers the image formed in the image forming unit onto a recording material. The fixing unit fixes the image to the recording material by heating the recording material conveyed from the transfer unit while sandwiching and conveying it at a nip. The duct has an intake port for drawing air from the vicinity of the pair of rotating bodies, and the intake port is located between the transfer unit and the nip in the recording material conveyance direction. The filter is made of electret fiber and is provided in the duct to collect fine particles resulting from the release agent. The first fan is a fan that blows air from the duct toward the outside of the machine to guide the air near the pair of rotating bodies to the filter. Patent Document 2 also describes that the image forming apparatus has a second fan that blows air from outside the apparatus toward the filter to cool the filter.

[0004] The following Patent Document 3 describes an image forming apparatus that includes a duct, a heat source, and a fixing device. The duct is a duct through which air flows. The heat source heats the air flowing through the duct. The fixing device is a device located outside the duct that fixes the toner image onto the recording medium. Patent Document 3 also describes that the duct has a communication part downstream of the heat source that connects the inside and outside of the duct and can suck in airflow from the fixing device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5271926 (Claim 1, Figures 1-3) [Patent Document 2] Patent No. 6708416 (Claim 1, Figures 4-6) [Patent Document 3] JP 2017-191227 A (Claim 1, Figures 1-5) Summary of the Invention [Problem to be solved by the invention]

[0006] A fixing system including a fixing device and an exhaust device has the following problems, for example. The fixing device fixes a toner image on a recording medium by passing the recording medium through a passage between the first and second rotating bodies. The exhaust device has a duct that sucks in air present on the outlet side of the passage through an intake port, flows it upward at least once, and then exhausts it to the outside. In the fixing system, unwanted matter made up of components contained in the air sucked into the duct may fall out of the duct. The present invention provides a fixing system and the like that can prevent unwanted matter from falling from the intake port of the duct of the exhaust device onto a recording medium passing through a passage of the fixing device. [Means for solving the problem]

[0007] The first aspect of the present invention is a fixing device having a first rotating body that is heated by a heating means and rotates, and a second rotating body that rotates while contacting the outer circumferential surface of the first rotating body to form a passage portion through which a recording medium on which a toner image is formed passes; a duct that draws in a portion of the air present on the outlet side of the passage through an intake port, flows it upward at least once, and then discharges it to the outside through an exhaust port; and an exhaust device having a fan that draws the air into the duct and generates a force to draw the air out. Equipped with The duct is a fixing system having an opening in the middle of the upward flow section that takes in air from outside the duct, a protrusion that protrudes into the inside of the duct on the inner wall surface opposite the opening, and a collection section below the protrusion that collects unwanted material that is generated inside the duct and falls.

[0008] A second aspect of the present invention is the fixing system of the first aspect, The opening is a fixing system having an inlet portion that introduces air in a direction perpendicular to or obliquely downward from the inside of the duct. A third aspect of the present invention is a fixing system according to the second aspect, The opening is a fixing system located near the intake.

[0009] A fourth aspect of the present invention is the fixing system of the first aspect, The protrusion is a fixing system configured of a plate-like member that extends and protrudes into the interior of the duct in a direction perpendicular to the interior of the duct or in a diagonally downward direction. A fifth aspect of the present invention is the fixing system according to the fourth aspect, The protrusion is a fixing system located below the opening.

[0010] A sixth aspect of the present invention is a fixing system according to the first aspect, The collection section is a fixing system recessed below the suction port. A seventh aspect of the present invention is the fixing system according to the sixth aspect, The collection section is a fixing system provided with an inlet plate extending horizontally from the boundary with the suction port to form the lower part of the suction port.

[0011] The eighth aspect of the present invention is an image forming unit that forms a toner image on a recording medium; a fixing unit that heats the toner image formed by the image forming unit to fix it on the recording medium; Equipped with The image forming apparatus is configured such that the fixing section is a fixing system according to any one of the first to seventh means. [Effects of the Invention]

[0012] According to the fixing system of the first means, it is possible to prevent unwanted matter from falling from the intake port of the duct of the exhaust device onto the recording medium passing through the passage of the fixing device.

[0013] According to the fixing system of the second means, it is easier to generate and collect unwanted matter in the upward flowing portion of the duct than when the opening does not have an introduction portion. According to the fixing system of the third means, unwanted substances can be generated and collected at a position close to the suction port.

[0014] According to the fixing system of the fourth means, unwanted material generated by the protrusion is more likely to fall downward than when the protrusion is composed of a plate-shaped member that extends diagonally upward inside the duct. According to the fixing system of the fifth means, unwanted matter is more likely to be generated at the protruding portion than when the protruding portion is provided at a position above the opening portion.

[0015] According to the fixing system of the sixth means, the falling unwanted matter can be collected so as not to leak out from the suction port. According to the fixing system of the seventh means, compared to when an inlet plate extending diagonally upward or downward is provided in the collection section, it is possible to prevent the air sucked in from the suction port from coming into contact with the lower or upper surface of the inlet plate, thereby preventing unwanted matter from being generated.

[0016] According to the image forming apparatus of the eighth aspect, it is possible to prevent unwanted matter from falling from the intake port of the duct of the exhaust device onto the recording medium passing through the passage of the fixing system. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to a first embodiment. [Figure 2] 1 is a schematic diagram of a fixing system according to a first embodiment. [Figure 3] FIG. 2 is a schematic perspective view of an exhaust device in the fixing system. [Figure 4] FIG. 2 is a schematic cross-sectional view of a main part of a first duct of the exhaust device. [Figure 5] 5 is a schematic cross-sectional view showing a state in which the first duct in FIG. 4 is discharging air. FIG. [Figure 6] FIG. 10 is a schematic cross-sectional view of a main part of an exhaust device in a fixing system according to a second embodiment. [Figure 7] 7 is a schematic cross-sectional view showing a state in which the first duct in FIG. 6 is discharging air. FIG. [Figure 8] FIG. 11 is a schematic cross-sectional view of a main part of an exhaust device in a fixing system according to a third embodiment. [Figure 9] 9 is a schematic cross-sectional view showing a state in which the first duct in FIG. 8 is discharging air. [Figure 10] FIG. 1 is a schematic diagram of a fixing system of a comparative example. [Figure 11]11 is a schematic cross-sectional view showing a state when exhausting air from a first duct in the fixing system of FIG. 10 and the occurrence of a malfunction. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described.

[0019] Embodiment 1 Fig. 1 is a schematic diagram of an image forming apparatus according to a first embodiment of the present invention, and Fig. 2 is a schematic diagram of a fixing system according to the first embodiment.

[0020] In this specification and the drawings, substantially the same components are denoted by the same reference numerals, and redundant explanations of the same components will be omitted in this specification. The arrow +X in Figure 1 etc. indicates the right direction when viewed from the front side of the image forming apparatus 1 etc., and the arrow -X indicates the left direction at that time. The arrow +Y in Figure 1 etc. indicates the upward direction of the image forming apparatus 1 etc., and the arrow -Y indicates the downward direction. The symbol +Z in Figure 1 etc. indicates the depth direction when viewed from the front side of the image forming apparatus 1 etc., and the symbol -Z indicates the forward direction at that time. In addition, the symbol "x" inside a "circle" in Figure 1 etc. indicates the direction from the front to the back of the paper of the drawing. The symbol "·" inside a "circle" in Figure 1 etc. indicates the direction from the back to the front of the paper of the drawing.

[0021] (Image forming device) The image forming apparatus 1 according to the first embodiment has an image forming unit 2, a medium supply unit 40, a fixing unit 50, and the like arranged inside a housing 10.

[0022] Of these, the housing 10 is a structure formed in a predetermined shape and having an internal space. The housing 10 is divided into an upper housing 10A and a lower housing 10B, for example, by a partition plate 11. The image forming unit 2, the fixing unit 50, etc. are arranged in the upper housing 10A. The medium supply unit 40, etc. are arranged in the lower housing 10B.

[0023] (Image forming section) The image forming unit 2 is a unit that forms a toner image as an unfixed image on a recording medium 9. The image forming unit 2 includes an image creating unit 20, an intermediate transfer unit 30, and a medium supply unit 40.

[0024] The image forming unit 20 is a part that forms a toner image by developing a latent image corresponding to image information with a developer. As shown in FIG. 1, the imaging section 20 in the first embodiment is made up of four imaging units 20A, 20B, 20C, and 20D.

[0025] The imaging units 20A, 20B, 20C, and 20D are electrophotographic units that create undeveloped images on the respective photosensitive drums 21 using developers of predetermined colors (A, B, C, and D). The predetermined colors (A, B, C, D) include, for example, yellow, magenta, cyan, black, and the like.

[0026] In addition, the imaging units 20A, 20B, 20C, and 20D are each provided with a charging device 22, an exposure device 23, a developing device 24, a drum cleaning device 26, and the like around the photosensitive drum 21. The reference numerals for the charging device 22, the exposure device 23, and the drum cleaning device 26 are shown only for the imaging unit 20D. The developing devices 24 are shown as developing devices 24A, 24B, 24C, and 24D because they use different colors of developer (A, B, C, and D).

[0027] The intermediate transfer section 30 is a section that relays the toner images formed by the image forming units 20A, 20B, 20C, and 20D of the image forming section 20 and transfers them onto the recording medium 9. The intermediate transfer unit 30 in the first embodiment includes an intermediate transfer belt 31, a primary transfer device 33, a secondary transfer device 34, a belt cleaning device 36, and the like.

[0028] The intermediate transfer belt 31 is an endless belt that can transport a toner image while holding it on its outer circumferential surface mainly by electrostatic force. The intermediate transfer belt 31 rotates while passing through each of the photosensitive drums 21 of the imaging units 20A, 20B, 20C, and 20D. Specifically, the intermediate transfer belt 31 is wound around a predetermined number of support rolls 32a, 32b, 32c, 32d, 32e, and 32f and rotates in the direction indicated by arrow B. Of these, the support roll 32a is a drive roll, and the support roll 32e is a secondary transfer back roll.

[0029] The primary transfer device 33 is a device that performs primary transfer of each toner image formed on each photosensitive drum 21 onto the outer circumferential surface of the intermediate transfer belt 31. In the intermediate transfer section 30, the position where the primary transfer device 33 faces each photosensitive drum 21 with the intermediate transfer belt 31 therebetween is the primary transfer position TP1. The primary transfer device 33 is a device that uses a primary transfer roll that rotates in contact with the outer circumferential surface of the intermediate transfer belt 31 at the primary transfer position TP1. A predetermined primary transfer bias is supplied to the primary transfer roll from a power supply device (not shown).

[0030] The secondary transfer device 34 is a device that performs secondarily transferring the toner image that has been primarily transferred onto the outer peripheral surface of the intermediate transfer belt 31 onto one side of the recording medium 9. In the intermediate transfer section 30, the position where the secondary transfer device 34 faces the support roll 32e with the intermediate transfer belt 31 sandwiched therebetween is the secondary transfer position TP2. The secondary transfer device 34 may be a device that uses a secondary transfer roll or a secondary transfer belt that rotates in contact with the outer circumferential surface of the intermediate transfer belt 31 at the secondary transfer position TP2. A predetermined secondary transfer bias is supplied to the secondary transfer roll or the roll that supports the secondary transfer belt from a power supply device (not shown). In the first embodiment, the secondary transfer device 34 is a device that rotatably supports the secondary transfer belt with two support rolls.

[0031] The medium supply unit 40 is a part that stores the recording medium 9 on which an image is to be formed and supplies it to a predetermined position in the image forming unit 2. The predetermined position in the first embodiment is the secondary transfer position TP2 of the intermediate transfer unit 30.

[0032] The medium supply unit 40 includes a container 41 that stores a plurality of recording media 9, and a delivery device 43 that delivers the recording media 9 one by one from the container 41. A loading plate on which the recording media 9 are loaded is arranged in the container 41. The recording medium 9 is a medium onto which a toner image can be transferred and held when conveyed to the image forming unit 2. As the recording medium 9, a medium such as paper cut to a predetermined size is used. A plurality of sets of the container 41 and the delivery device 43 may be provided.

[0033] In the housing 10, a medium transport path Rt, which is illustrated by a dashed line in FIG. The medium transport path Rt includes a supply transport path Rt1, a relay transport path Rt2, a discharge transport path Rt3, and the like.

[0034] The supply transport path Rt1 is made up of a predetermined number of transport roll pairs 45a, 45b, and 45c, transport guide members (not shown), and the like. The relay conveying path Rt2 is composed of a suction-type belt conveying device 46. The belt conveying device 46 is equipped with a suction device. The belt conveying device has a conveying belt with multiple suction holes formed therein wound around two support rolls and rotates it in a predetermined direction. The suction device sucks air from the inner peripheral surface side of the conveying belt, and adsorbs the recording medium 9 to the outer peripheral surface on the upper surface side of the conveying belt. The discharge transport path Rt3 is a transport path that connects the fixing unit 50 and the discharge outlet 13. The discharge transport path Rt3 is made up of a predetermined number of transport roll pairs 47a, 47b, a transport guide member (not shown), etc. The discharge outlet 13 is an opening through which the recording medium 9 is conveyed out, and is provided at a predetermined position on one side of the housing 10.

[0035] The image forming unit 2 forms a toner image on the recording medium 9 as follows. Here, a description will be given assuming that toner images are formed in all of the image forming units 20A, 20B, 20C, and 20D.

[0036] First, in the image forming units 20A, 20B, 20C, and 20D of the image forming section 20, when a command for an image forming operation is received, each photosensitive drum 21 starts to rotate in the direction indicated by arrow A. In the intermediate transfer unit 30, the intermediate transfer belt 31 starts to rotate in the direction indicated by the arrow B when the image forming operation starts.

[0037] Subsequently, in the imaging units 20A, 20B, 20C, and 20D, the charging devices 22 charge the outer circumferential surfaces of the respective photosensitive drums 21 to a predetermined surface potential. Thereafter, each exposure device 23 exposes the charged outer peripheral surface of each photosensitive drum 21 to light of each color component configured in accordance with the image information, thereby forming an electrostatic latent image divided into predetermined color components (A, B, C, D) on the outer peripheral surface of each photosensitive drum 21. Image information is input from an externally connected device (not shown), such as an information terminal or storage medium, connected to the image forming apparatus 1.

[0038] Next, each developing device 24A, 24B, 24C, and 24D develops the electrostatic latent image on the outer circumferential surface of each photosensitive drum 21 with a developer of the corresponding color. As a result, a toner image of a predetermined color (A, B, C, or D) is formed separately on the outer circumferential surface of each photosensitive drum 21. Subsequently, in the image forming units 20A, 20B, 20C, and 20D of the image forming section 20, the toner images on the photosensitive drums 21 are transferred to the intermediate transfer section 30.

[0039] Finally, in the imaging units 20A, 20B, 20C, and 20D, the drum cleaning device 26 cleans the outer circumferential surface of each photosensitive drum 21 after transfer. After the photosensitive drums 21 of the image forming units 20A, 20B, 20C, and 20D of the image forming section 20 are cleaned, the image forming units 20A, 20B, 20C, and 20D are each prepared for the next image forming process.

[0040] Meanwhile, in the intermediate transfer unit 30, the primary transfer device 33 sequentially performs primary transfer of the toner images on the photosensitive drums 21 onto the outer circumferential surface of the intermediate transfer belt 31 passing through the primary transfer position TP1. At this time, the intermediate transfer belt 31 carries the toner image that has been primarily transferred onto its outer circumferential surface to the secondary transfer position TP2. Furthermore, in the medium supply unit 40, in accordance with the secondary transfer timing, the delivery device 43 delivers a predetermined recording medium 9 from the container 41 toward the secondary transfer position TP2 of the intermediate transfer unit 30. At this time, the recording medium 9 is transported to the secondary transfer position TP2 via the supply transport path Rt1.

[0041] Subsequently, in the intermediate transfer unit 30, the secondary transfer device 34 performs secondary transfer of the toner image onto the recording medium 9 from the outer circumferential surface of the intermediate transfer unit 30 which passes through the secondary transfer position TP2. Finally, in the intermediate transfer unit 30, the belt cleaning device 36 cleans the outer peripheral surface of the intermediate transfer belt 31 after the secondary transfer. After the intermediate transfer belt 31 is cleaned, the intermediate transfer unit 30 prepares for the next transfer step.

[0042] The recording medium 9 onto which the toner image has been secondarily transferred in the intermediate transfer unit 30 is transported to be introduced into the fixing unit 50 via a relay transport path Rt2. In the relay transport path Rt2, a suction type belt transport device 46 transports the recording medium 9 while sucking it.

[0043] (Fusing unit and fusing system) The fixing unit 50 is a part that heats the unfixed toner image transferred onto the recording medium 9 to fix it onto the recording medium 9 . As shown in FIGS. 1 and 2, the fixing section 50 is configured with the fixing system 5 according to the first embodiment.

[0044] The fixing system 5 constituting the fixing section 50 is a system in which a heating type fixing device 51 and an exhaust device 60 are combined.

[0045] (fixing device) The fixing device 51 includes a fixing housing 52 and includes a first rotating body 53 having a heating means 54, a second rotating body 55, and the like.

[0046] The fixing housing 52 is a heat-resistant structure having an internal space and a predetermined shape. The fixing housing 52 has an elongated shape extending in a direction perpendicular to the plane of the paper in FIG. 2 (the direction indicated by -Z). The fixing housing 52 has an inlet 52a for introducing the recording medium 9 and an outlet 52b for discharging the recording medium 9 formed on opposing side surfaces. The inlet 52a and the outlet 52b are openings that are elongated in the depth direction.

[0047] The fixing housing 52 also includes an introduction device 56 and an introduction guide member 57 that introduce the recording medium 9 to be fixed from the introduction port 52a into a passage FN, which will be described later. The introduction device 56 is a conveying device that stretches the medium conveying belt 56a around two support rolls and rotates it in the direction indicated by the dashed arrow. The introduction guide member 57 is disposed between the introduction device 56 and a position on the front side of the passage FN.

[0048] Furthermore, the fixing housing 52 is provided with a discharge guide member 58 and a discharge device 59 for discharging the recording medium 9 after fixing from a position on the discharge side of a passage FN (to be described later) to a discharge port 52b. The discharge guide member 58 is disposed between the discharge side of the passage FN and the discharge device 59. The discharge device 59 is a transport device that loops a medium transport belt 59a around three support rolls and rotates it in the direction indicated by the dashed arrow. Reference numeral 52e in FIG. 2 denotes a partition plate.

[0049] The first rotor 53 is a rotor that rotates while being heated. First rotating body 53 in the first embodiment is a rotating body that rotates fixing belt 531 while heating it by wrapping it around a predetermined number of rolls. The predetermined number of rolls include first heating roll 532, second heating roll 533, external heating roll 534, support rolls 535 and 536, etc. The first rotating body 53 that rotates such a belt is, so to speak, a rotating body in the form of a belt.

[0050] The fixing belt 531 is a belt that performs a fixing process by contacting the outer circumferential surface of the belt with an unfixed toner image on the recording medium 9. The fixing belt 531 is formed as an endless belt.

[0051] The first heating roll 532 is a heating roll disposed at a position facing the second rotating body 55. The first heating roll 532 has a heating means 54A disposed inside the hollow of the cylindrical roll body, and is heated by the heating means 54A. The first heating roll 532 comes into contact with the inner circumferential surface of the fixing belt 531 and heats it from the inner circumferential surface side. The first heating roll 532 forms a passage FN (described later) between itself and the second rotating body 55 with the fixing belt 531 sandwiched therebetween.

[0052] The second heating roll 533 is a heating roll that is arranged at a position above and apart from the first heating roll 532. The second heating roll 533 has a heating means 54B arranged inside the hollow of the cylindrical roll body, and is heated by the heating means 54B. The second heating roll 533 comes into contact with the inner circumferential surface of the fixing belt 531 and heats it from the inner circumferential surface side.

[0053] The external heating roll 534 is a heating roll that is disposed at a position between the first heating roll 532 and the second heating roll 533. The external heating roll 534 has a heating means 54C disposed inside the hollow of the cylindrical roll body, and is heated by the heating means 54C. The external heating roll 534 comes into contact with the outer circumferential surface of the fixing belt 531 and heats it from the outer circumferential surface side. Further, the external heating roll 534 applies tension to the fixing belt 531 from the outer circumferential surface side of the belt.

[0054] The support roll 535 is a roll that is disposed at a position between the first heating roll 532 and the external heating roll 534. The support roll 535 supports the part of the fixing belt 531 that has passed through the passing portion FN so that the part passes through a position away from the first heating roll 532.

[0055] The support roll 536 is a roll disposed at a position between the second heating roll 533 and the first heating roll 532. The support roll 536 supports the fixing belt 531 so that the fixing belt 531 passes through a position outside the linear area connecting the second heating roll 533 and the first heating roll 532. The support roll 536 is configured as a meandering suppression roll that suppresses meandering of the fixing belt 531. The meandering suppression roll is called, for example, a steering roll.

[0056] The heating means 54A, 54B, and 54C are not particularly limited in terms of conditions such as heating type, as long as they are capable of performing the desired heating.

[0057] The second rotating body 55 is a rotating body that comes into contact with the outer peripheral surface of the first rotating body 53 and rotates while forming a passing portion FN through which the recording medium 9 on which the toner image TI is formed passes. The passage FN may also be called a fixing nip because it sandwiches the unfixed toner image between the recording medium 9 and the passage FN to fix the toner image to the recording medium 9. A cylindrical pressure roll is used as the second rotating body 55 in the first embodiment. The second rotating body 55 that rotates such a roll is, so to speak, a rotating body in the form of a roll.

[0058] The pressure roll, which is the second rotating body 55, receives pressure from a pressure mechanism (not shown) via a support frame (not shown). As the pressure mechanism, for example, a spring mechanism or a cam mechanism is applied. As a result, the pressure roll, which is the second rotor 55, comes into contact with the first rotor 53 at a predetermined pressure in the passing portion FN. Furthermore, the pressure roll, which is the second rotating body 55, is configured to receive rotational power from a rotation drive device (not shown) and be driven to rotate in the direction indicated by the arrow. When the pressure roll, which is the second rotating body 55, is driven to rotate and passes through the passing portion FN, it transmits the rotational power to the fixing belt 531, which is the first rotating body 53. As a result, the second rotating body 55 functions to rotate the fixing belt 531 in the direction indicated by the arrow.

[0059] The fixing of the toner image by the fixing device 51 is carried out as follows.

[0060] First, in the fixing device 51, when the device is in operation, such as during an image forming operation, the pressure roll, which is the second rotating body 55, starts to rotate in the direction indicated by the arrow. As a result, the fixing belt 531, which is the first rotating body 53, receives the rotational power of the pressure roll and starts to rotate in the direction indicated by the arrow. Further, the first heating roll 532, the second heating roll 533, and the external heating roll 534 start to be heated by the heating means 54A, 54B, and 54C, respectively, whereby the fixing belt 531, which is the first rotating body 53, is heated to a predetermined temperature.

[0061] Next, the recording medium 9 on which the unfixed toner image TI is formed is introduced via the relay conveyance path Rt2 into the fixing device 51. At this time, the recording medium 9 is carried in from the inlet 52a by the introduction device 56 or the like and introduced into the passage FN. When the recording medium 9 passes through the passage FN, the fixing device 51 heats the toner image TI at a predetermined fixing temperature under pressure to fix it onto the recording medium 9. Furthermore, the recording medium 9 after fixing that has passed through the passage FN is carried out of the fixing device 51 by the carry-out device 59 or the like and discharged from the discharge port 52b. With the above, the fixing of the toner image by the fixing device 51 is completed.

[0062] After fixing, the recording medium 9 is discharged from the discharge port 52b of the housing 10 via the discharge transport path Rt3 to a discharge storage unit (not shown). The discharge and storage section is formed, for example, of a plate-like member having a storage surface.

[0063] (Exhaust system) The exhaust device 60 is a device that exhausts air inside the fixing housing 52 of the fixing device 51 to the outside. The exhaust device 60 includes at least a duct 61 and a fan 68 .

[0064] Exhaust device 60 in the first embodiment includes two ducts, a first duct 61A and a second duct 61B, as ducts 61. Exhaust device 60 also includes two fans, a first fan 68A and a second fan 68B, as fans 68.

[0065] The first duct 61A is a duct that draws in and circulates a portion of the air Ae that is present on the outlet side of the passage FN inside the fixing housing 52. The outlet side of the passage FN is the side from which the recording medium 9 passes through the passage FN and is discharged.

[0066] The first duct 61A is configured as a duct that draws in a portion of the air Ae from an inlet 611A, flows it upward once, and then discharges it from an outlet 612A. The first duct 61A also has a duct body 610A that connects the inlet 611A and the outlet 612A.

[0067] As shown in FIG. 3 and other figures, the duct body 610A in the first embodiment is configured as a plate-like pipe formed into a predetermined shape. The duct body 610A has a shape including an upright portion 610Aa, a horizontal portion 610Ab, and a discharge portion 610Ac.

[0068] The rising portion 610Aa is a duct portion that rises in an almost straight line in the upward direction (+Y). The rising portion 610Aa has an intake port 611A at its lower end. The rising portion 610Aa is disposed close to the side portion of the fixing housing 52 where the exhaust port 52b is provided. The horizontal portion 610Ab is a duct portion that is connected to the upper end of the rising portion 610Aa and extends substantially horizontally. The horizontal portion 610Ab is disposed close to a part of the upper surface of the fixing housing 52. The exhaust section 610Ac is a duct section that extends from the exhaust terminal end of the horizontal section 610Ab to the exhaust port on the rear side of the housing 10, which is the exhaust destination. The exhaust section 610Ac has an exhaust port 612A at its terminal end. A filter (not shown) that captures and removes dust and the like is installed inside the exhaust section 610Ac.

[0069] Inlet port 611A is provided in a portion of rising portion 610Aa of duct main body 610A that faces the upper portion of outlet port 52b of fixing housing 52. Inlet port 611A is formed as a substantially rectangular opening that extends long along the depth direction (-Z) of fixing housing 52. The outlet 612A is connected to an exhaust port (not shown) provided on the rear surface or the like of the housing 10 of the image forming apparatus 1. The outlet 612A is formed as an opening having a rectangular or other shape at the end of the outlet portion 610Ac of the duct main body 610A.

[0070] The first fan 68A is a blower that generates a force to draw air into the first duct 61A and to cause the air to flow. The first fan 68A is installed, for example, in the middle of the discharge section 610Ac of the duct main body 610A. As the first fan 68A, any type of fan such as an axial fan, a centrifugal fan, or a blower fan is used.

[0071] On the other hand, the second duct 61B is a duct that mainly draws in and flows a part of the air At present in the upper part of the interior of the fixing housing 52. The second duct 61B is configured as a duct that draws in a portion of the air At from an inlet 611B and then discharges the air At from an outlet 612B.

[0072] The second duct 61B also has a duct body 610B that connects the inlet 611B and the outlet 612B. As shown in FIG. 3 and other figures, the duct body 610B in the first embodiment is a plate-like tube formed into a predetermined shape. The duct body 610B has a horizontal portion 610Bb and a discharge portion 610Bc.

[0073] The horizontal portion 610Bb is a portion having a shape that extends substantially horizontally on the upper surface of the fixing housing 52. The horizontal portion 610Bb is disposed close to the remaining part of the upper surface of the fixing housing 52. The exhaust section 610Bc is a section having a shape that extends from the exhaust terminal end of the horizontal section 610Bb to the exhaust port on the rear side of the housing 10, which is the exhaust destination. The exhaust section 610Bc has an exhaust port 612B at its terminal end. A filter (not shown) that captures and removes dust and the like is installed inside the exhaust section 610Bc.

[0074] Inlet port 611B is provided on the lower surface of horizontal portion 610Bb of duct main body 610A at a location facing the upper surface of fixing housing 52. Inlet port 611B is formed as a substantially rectangular opening that extends long along the depth direction (-Z) of fixing housing 52. The outlet 612B is arranged in a state connected to an exhaust port (not shown) provided on the rear part or the like of the housing 10 of the image forming apparatus 1. The outlet 612B is formed as an opening having a rectangular shape or the like at the end of the outlet portion 610Bc of the duct main body 610B.

[0075] The second fan 68B is a blower that generates a force to draw air into the second duct 61B and cause it to flow. Second fan 68B is installed, for example, in the middle of discharge section 610Bc of duct main body 610B. The same fan as first fan 68A is used as second fan 68B, but it may be a different fan.

[0076] The exhaust by the exhaust device 60 is carried out as follows.

[0077] In the exhaust device 60, when the exhaust device 60 is in operation, such as during an image forming operation, the first fan 68A and the second fan 68B start operating. As a result, in the first duct 61A and the second duct 61B, a force is generated that draws air into the hollow interior of each duct main body 610A, 610B and causes it to flow.

[0078] At this time, the first duct 61A draws in part of the air Ae present inside the fixing housing 52 on the outlet side of the passage FN through the suction port 611A. Air Ae drawn into first duct 61A flows upward through rising portion 610Aa. Then, the air Ae passes through horizontal portion 610Ab and discharge portion 610Ac in that order, and is finally discharged to the outside through discharge port 612A. The flow of air Ae at this time is shown by the dashed arrowed lines in FIG. 2.

[0079] At this time, the second duct 61B also draws in a portion of the air At present on the upper side inside the fixing housing 52 through the intake port 611B. The air At drawn into the second duct 61B flows through the horizontal portion 610Bb. After that, the air At passes through the discharge portion 610Bc and is finally discharged from the discharge port 612B. The flow of the air At at this time is shown by the dashed arrowed lines in FIG. 2.

[0080] The exhaust device 60 can exhaust high-temperature air (hot air) generated inside the fixing housing 52 of the fixing device 51 to the outside. This prevents the fixing device 51 and its surrounding area from excessively increasing in temperature during operation of the fixing device 51, and keeps the temperature environment at a moderate level.

[0081] (Problem occurring in the fixing system) In the fixing system 5 constituting the fixing section 50, the following problems may occur due to the exhaust device 60.

[0082] Here, the above-mentioned problem will be described based on a fixing system 5X as a comparative example shown in FIG. The fixing system 5X has the same configuration as the fixing system 5 according to the first embodiment, except that an exhaust device 60X for comparison is used. The comparative exhaust device 60X differs from the exhaust device 60 in the first embodiment in the following respects: The exhaust device 60X employs a first duct 61X that does not include an opening 63, a protruding portion 64, and a collecting portion 65, which will be described later. The first duct 61X is a duct that includes an inlet 611A, an outlet 612A, and a duct body 610X that connects them.

[0083] In the fixing system 5X of the comparative example, waste matter 100 is generated inside the first duct 61X of the exhaust device 60X, as illustrated in Fig. 11. This waste matter 100 is likely to be generated inside the rising portion 610Xa of the first duct 61X. In the fixing system 5X, some of the unwanted matter 100 may fall from the suction port 611A and adhere to the recording medium 9.

[0084] At this time, part of the air Ae present inside the fixing housing 52 on the outlet side of the passage FN is sucked into the first duct 61X. The air Ae contains components such as wax contained in the toner of the toner image that have been volatilized by the heat of the passage FN, and these volatilized components exist as, for example, oil mist. Ae1 indicated by a dashed line with an arrow in Fig. 11 is an airflow of the air Ae that flows in contact with the first inner wall surface 610a of the first duct 61X. Ae2 indicated by a dashed line with an arrow in Fig. 11 is an airflow of the air Ae that flows in contact with the second inner wall surface 610b of the first duct 61X. The first inner wall surface 610a is an inner wall surface that is relatively far from the fixing housing 52. The second inner wall surface 610b is an inner wall surface that is relatively close to the fixing housing 52. Reference numeral 610c in FIG. 11 etc. indicates the inner wall surface on the far side.

[0085] The waste 100 is formed when part of the air Ae that is sucked into the first duct 61X and moves comes into contact with the inner wall surface of the first duct 61X and condenses. The waste 100 is generated, for example, when the oil mist adheres to the inner wall surface. Furthermore, the waste 100 adheres to the inner wall surface of the first duct 61X and increases in number, and then moves downwards, dripping down.

[0086] At this time, the unwanted matter 100 may fall onto the fixed recording medium 9 that has passed through the passage FN. In this case, the fixed recording medium 9 is contaminated by the unwanted matter 100 adhering thereto, resulting in poor image quality. For example, when the fixing temperature is increased in accordance with an increase in driving speed in order to improve the productivity of the image forming operation, the amount of the waste 100 generated also increases, making the waste 100 more likely to fall.

[0087] (Details of the exhaust system) Therefore, in the fixing system 5 according to the first embodiment, as shown in FIGS. 2 to 4, a duct having at least the opening 63, the protruding portion 64, and the collecting portion 65 is employed as the first duct 61A.

[0088] Of these, the opening 63 is an opening that takes in air from outside the duct main body 610A at a position midway along the rising portion 610Aa of the first duct 61A. The outside of duct main body 610 is the outside opposite to fixing housing 52, and is also the outside near opening 63. Upright portion 610Aa is a duct portion of duct main body 610 that causes air to flow upward.

[0089] The opening 63 is provided in a first side surface of the rising portion 610Aa of the first duct 61A that is relatively far from the fixing housing 52. The first side surface is also a side surface that faces the second side surface in which the suction port 611A is provided.

[0090] Opening 63 in the first embodiment is provided as a long and narrow rectangular opening along the depth direction (-Z) of the first side surface portion, and therefore has upper side 63a and lower side 63b that extend substantially parallel to each other along the depth direction (-Z). The opening 63 is provided so that the height H1, which is the opening dimension in the vertical direction, is a predetermined dimension. The height H1 is set to a dimension within the range of 1 to 3 cm, for example. The opening 63 is provided, for example, at a height such that a horizontal imaginary line VLb passing through the lower side 63b thereof overlaps with a part of the protrusion 64. The symbol VLa in FIG. 4 is an imaginary horizontal line passing through the upper side 63a of the opening 63. Furthermore, opening 63 is provided in the lower half of rising portion 610Aa. Opening 63 is provided in rising portion 610Aa at a position close to inlet 611A.

[0091] Next, the protruding portion 64 is a portion of the inner wall surface facing the opening 63 that protrudes into the inside of the duct main body 610A. The inner wall surface facing the opening 63 becomes a second inner wall surface 610b, which is relatively closer to the fixing housing 52, among the inner wall surfaces of the rising portion 610Aa.

[0092] The protrusion 64 is provided on a second inner wall surface 610b of the inner wall surface of the rising portion 610Aa of the first duct 61A. The second inner wall surface 610b is also an inner wall surface that faces the first inner wall surface 610a of the rising portion 610Aa on the side relatively farther from the fixing housing 52.

[0093] Protrusion 64 in the first embodiment is provided as a plate-like member having an elongated rectangular shape along the depth direction (-Z) of second inner wall surface 610b. The plate-like member may be any member having a plate shape with upper surface 64a and lower surface. Furthermore, the protruding portion 64 made of a plate-like member is provided so that its upper surface 64a forms an inclined surface with a predetermined angle α with respect to an imaginary extension line VLd along the second inner wall surface 610b. The angle α is preferably less than 90 degrees. If the angle α is 90 degrees or more, the waste material 100 will be unnecessarily accumulated on the upper surface 64a of the protruding portion 64.

[0094] Furthermore, the protruding portion 64 made of a plate-like member is provided so that the protruding amount E1 from the second inner wall surface 610b is a predetermined dimension. The protrusion amount E1 is preferably a value in the range of ⅓ to ⅔ of the distance S1 between the first inner wall surface 610a and the second inner wall surface 610b of the raised portion 610Aa. When the protrusion amount E1 is less than one-third of the spacing S1, intentional aggregation of unwanted substances is unlikely to occur. Conversely, when the protrusion amount E1 is more than two-thirds of the spacing S1, the internal space of the rising portion 610Aa is narrowed by the protrusion 64, making it difficult to efficiently draw in air Ae.

[0095] In addition, it is preferable that the protrusion 64 is provided so that its upper surface 64 a faces the opening 63 . Furthermore, the protruding portion 64 is preferably provided so as to protrude from a height position lower than the height (VLb) of the lower side 63b of the opening 63. Furthermore, it is preferable that the protruding portion 64 is provided in a position close to the suction port 611A in the lower half of the rising portion 610Aa.

[0096] Next, the collecting section 65 is a section that collects the waste 100 that is mainly generated and falls inside the rising portion 610Aa of the duct main body 610A. The waste is generated by, for example, aggregation. The collection portion 65 is provided at a position lower than the protrusion 64 .

[0097] As shown in FIG. 4, collection section 65 in the first embodiment is recessed downward from suction port 611A. Furthermore, collection section 65 is provided so that depth D1 from lower end 611Ad of suction port 611A has a predetermined dimension. Depth D1 is set to a dimension that allows sufficient storage of generated unwanted materials without leakage. Furthermore, the collection portion 65 is provided in a positional relationship such that at least the tip (lower end) 64e of the protrusion 64 is located directly above it.

[0098] Furthermore, the opening 63 in the first embodiment is provided with an introduction portion 66 as shown in FIG.

[0099] The introduction section 66 is a section that guides air outside the rising section 610Aa of the first duct 61A so that the air is introduced into the rising section 610Aa at a predetermined angle. The predetermined angle is either a direction perpendicular to the first inner wall surface 610a or a direction diagonally downward relative to the interior of the rising section 610Aa.

[0100] The introduction portion 66 in the first embodiment is provided as a plate-like member that protrudes outward from the rising portion 610Aa from the lower side 63b of the opening 63. The plate-like member has an upper surface 66a that intersects with the lower side 63b of the opening 63. The introduction portion 66 made of a plate-like member is provided so that its upper surface 66a is an inclined surface that forms a predetermined angle β with the outer surface of the first side surface portion. Angle β is preferably equal to or greater than 90 degrees. If angle β is less than 90 degrees, the air flowing in from opening 63 cannot collide with and disturb the flow of air Ae sucked in from intake port 611A.

[0101] The introduction portion 66 is also provided so that the protrusion amount J1, the amount by which the upper surface 66a of the introduction portion 66 protrudes from the outer surface of the first side surface portion, is a predetermined value. The protrusion amount J1 is set from the viewpoint of obtaining the function of guiding and introducing outside air at a predetermined angle. The protrusion amount J1 is preferably, for example, 2 cm or more. In addition, the introduction portion 66 is provided in a positional relationship in which an imaginary passing line VLe passing along the upper surface 66a thereof intersects with a part of the protrusion 64.

[0102] As shown in FIG. 4, the collection section 65 is provided with an inlet plate 67.

[0103] Inlet plate 67 is a plate-like portion that extends outward in the horizontal direction from the boundary with suction port 611A so as to form the lower part of suction port 611A. Inlet plate 67 in the first embodiment is provided in a state of protruding outward away from suction port 611A, substantially perpendicular to lower end 611Ad of suction port 611A. The dashed dotted line indicated by the symbol VLf in FIG. 4 is an imaginary passing line that passes through the lower end 611Ad of the suction port 611A and runs along the upper surface 67a of the inlet plate 67.

[0104] <Function of the exhaust device in the fixing system> In the fixing system 5 according to the first embodiment, when the exhaust device 60 is in operation, the first duct 61A is in the state described below.

[0105] In the first duct 61A, the operation of the first fan 68A generates a force that draws air into the inside of the duct and causes it to flow. This flowing force is a suction force, and appears as an airflow AF as shown in FIG.

[0106] Due to this flow force, in the first duct 61A, a portion of the air Ae present on the outlet side of the passage FN is sucked in through the suction port 611A. Hereinafter, this portion of the air Ae will be referred to as air Ae1. The sucked in air Ae1 flows upward through the rising portion 610Aa of the first duct 61A.

[0107] Moreover, the air Ak outside the first duct 61A is taken in through the opening 63 in the first duct 61A by the above-mentioned flow force. 5, the air Ak at this time includes a portion of air Ak1 that flows substantially along the upper surface 66a formed by the slope of the introduction portion 66. This portion of air Ak1 tends to flow toward the protrusion 64 at its destination. The air Ak at this time also includes a portion of air Ak2 that flows upward immediately after passing through the opening 63.

[0108] For this reason, while flowing upward in rising portion 610Aa, air Ae1 collides with air Ak1, Ak2 taken in from opening 63. In other words, air Ak1, Ak2 taken in from opening 63 collides with air Ae1 taken in from suction port 611A. This collision occurs early after air Ae1 passes through suction port 611A because opening 63 is located close to suction port 611A of rising portion 610Aa.

[0109] Due to this collision, the air Ae1 temporarily stagnates and circulates inside the duct, as illustrated by the dashed two-dot line Aes with an arrow in Figure 5. At this time, the air Ae1 stagnates as if it is pressed against the protruding portion 64 of the rising portion 610Aa and the second inner wall surface 610b portion above it. At this time, the air Ae1 stagnates near the suction port 611A because the protruding portion 64 is provided in a position close to and adjacent to the suction port 611A of the rising portion 610Aa. Moreover, if the stagnant air Ae1 contains components such as wax, it is likely to come into contact with the protrusion 64 and the second inner wall surface 610b portion thereof. As a result, unwanted matter 100 caused by the air Ae1 is likely to be generated on the protrusion 64 and the second inner wall surface 610b portion thereof.

[0110] As a result, in the first duct 61A, the waste matter 100 adheres to and aggregates on the protruding portion 64 of the rising portion 610Aa and on the second inner wall surface 610b above it. Then, as shown in FIG. 5, the waste material 100 travels down the upper surface 64a, which is the downward slope of the protruding portion 64, and falls from the tip 64e. The fallen waste material 100 falls into and is collected in the collection section 65 located almost directly below the protrusion 64. At this time, the waste material 100 is stored in the recessed collection section 65 and does not overflow.

[0111] Therefore, in the fixing system 5, the unwanted matter 100 is prevented from falling from the suction port 611A of the first duct 61A of the exhaust device 60 onto the recording medium 9 passing through the passage FN of the fixing device 51. As a result, in the image forming apparatus 1 equipped with the fixing system 5, the recording medium 9 is not contaminated by the unwanted matter 100 falling on it after fixing. In addition, poor image quality due to the unwanted matter 100 adhering to the recording medium 9 is also prevented.

[0112] Furthermore, the fixing system 5 is provided with an introduction section 66 at the opening 63 of the first duct 61A. As a result, in the fixing system 5, the opening 63 can more easily take in the air Ak outside the rising portion 610Aa of the first duct 61A in a predetermined direction, compared to when the opening 63 does not have the introduction portion 66. As a result, in the fixing system 5, the unwanted matter 100 can be generated and collected more easily in the rising portion 610Aa of the first duct 61A than in a configuration in which the introduction portion 66 introduces the unwanted matter 100 by moving it in an upward direction inside the duct. This is promoted by the intake of the air Ak along a predetermined direction.

[0113] Furthermore, in the fixing system 5, the protruding portion 64 of the first duct 61A is provided at a position lower than the opening 63. As a result, in the fixing system 5, the outside air Ak taken in through the opening 63 is more likely to flow toward the protrusion 64 located below the opening 63. As a result, in the fixing system 5, the protruding portion 64 is more likely to generate waste 100 than when the protruding portion 64 is provided at a position higher than the opening 63. Moreover, the waste 100 generated at the protruding portion 64 moves along the upper surface 64a, which is the downward slope of the protruding portion 64, and then falls into the collecting portion 65 below the protruding portion 64 to be collected.

[0114] Furthermore, the fixing system 5 is provided with an inlet plate 67 in the collecting section 65 of the first duct 61A. As a result, a portion Ae2 of the air Ae sucked in through the suction port 611A is sucked in while being guided to the upper surface 67a of the inlet plate 67 which is in a horizontal position, as shown in FIG. As a result, in the fixing system 5, it is possible to prevent a portion Ae2 of the air Ae sucked in from the suction port 611A from coming into contact with the lower surface 67b or the upper surface 67a of the inlet plate 67, which extends obliquely upward or downward, and generating waste matter 100. It is also possible to prevent the waste matter 100 from falling off the lower surface 67b or the upper surface 67a of the inlet plate 67 without being collected in the collection unit 65.

[0115] Embodiment 2 FIG. 6 is a schematic cross-sectional view showing a main part of an exhaust device in a fixing system according to the second embodiment. The fixing system according to the second embodiment differs from the fixing system 5 according to the first embodiment (see FIG. 2, etc.) only in that the first duct 61A of the exhaust device is changed to a first duct 61C. The first duct 61C in the second embodiment has the same configuration as the first duct 61A in the first embodiment, except that the protruding portion 64 is changed to a protruding portion 64B and the introduction portion 66 is changed to an introduction portion 66B.

[0116] In the protrusion 64B, the angle α formed by the upper surface 64a and the imaginary extension line VLd along the second inner wall surface 610b is changed to an angle larger than the angle α in embodiment 1. In embodiment 2, the angle α is changed to an angle close to 90 degrees (for example, 88 degrees). Furthermore, the amount of protrusion E1 of protrusion 64B from second inner wall surface 610b is substantially the same as the amount of protrusion E1 in the first embodiment. Furthermore, the protrusion 64B is provided at a position lower than the opening 63.

[0117] The introduction portion 66B is provided as a plate-like member that protrudes obliquely upward from the upper side 63a of the opening 63 to the outside of the rising portion 610Aa. The angle β formed by the lower surface 66c of the introduction portion 66B and the outer surface of the first side surface portion is substantially the same as the angle β in the first embodiment. Furthermore, the introduction portion 66B has a protrusion amount J2, which is the amount by which the lower surface 66c thereof protrudes from the outer surface of the first side surface portion, that is approximately the same as the protrusion amount J1 in the first embodiment. In addition, the introduction portion 66B is provided in a positional relationship such that an imaginary path line VLg passing along the lower surface 66c thereof intersects with the second inner wall surface 610b at a portion above the protrusion 64B.

[0118] The upper end of the intake port 611A of the first duct 61C starts from the lower surface of the protruding portion 64B. In addition, the first duct 61C has a slope that slopes downward from the lower side 63b of the opening 63 toward the inside of the duct, with the slope having approximately the same inclination angle as the lower surface 66c of the introduction portion 66B.

[0119] <Function of First Duct in Second Embodiment> In first duct 61C, operation of first fan 68A generates a flowing force similar to that in first duct 61A in embodiment 1. This flowing force also appears as an airflow AF as illustrated in FIG.

[0120] Due to this flow force, first, in the first duct 61C, air Ae1, which is part of the air Ae present on the outlet side of the passage FN, is sucked in through the suction port 611A. The sucked air Ae1 then flows upward through the rising portion 610Aa of the first duct 61C.

[0121] Moreover, the air Ak outside the first duct 61C is also taken in through the opening 63 in the first duct 61C by the above-mentioned flowing force. 7, the air Ak at this time includes a portion of air Ak3 that flows substantially along the lower surface 66c formed by the slope of the introduction portion 66B. This portion of air Ak3 tends to flow toward a portion of the second inner wall surface 610b of the rising portion 610Aa that is slightly above the protruding portion 64B. The air Ak at this time also includes a portion of air Ak2 that flows upward immediately after passing through the opening 63.

[0122] Therefore, while flowing upward in the rising portion 610Aa, the air Ae1 collides with the air Ak2 and Ak3 taken in from the opening 63. In other words, the air Ak2 and Ak3 taken in from the opening 63 collides with the air Ae1 sucked in from the suction port 611A.

[0123] Due to this collision, the air Ae1 temporarily stagnates and circulates inside the duct, as illustrated by the dashed two-dot line Aes with an arrow in Fig. 7. The air Ae1 at this time also stagnates, being pressed against the protruding portion 64B of the rising portion 610Aa and the second inner wall surface 610b above it. Moreover, if the stagnant air Ae1 contains components such as wax, it will come into contact with the protruding portion 64B and the second inner wall surface 610b portion above it, which will easily generate waste matter 100.

[0124] As a result, in the first duct 61C, the waste matter 100 adheres to and aggregates on the protruding portion 64B of the rising portion 610Aa and the second inner wall surface 610b above it. Then, as shown in FIG. 7, the waste material 100 travels down the slightly downwardly inclined upper surface 64a of the protruding portion 64B and falls from the tip 64e. The fallen waste material 100 falls into the collecting section 65 located almost directly below the protruding section 64 and is collected.

[0125] Therefore, in the fixing system according to the second embodiment, the unwanted matter 100 is prevented from falling from the intake port 611A of the first duct 61C of the exhaust device 60 onto the recording medium 9 passing through the passage FN of the fixing device 51.

[0126] Embodiment 3 FIG. 8 is a schematic cross-sectional view showing a main part of an exhaust device in a fixing system according to the third embodiment. The fixing system according to the third embodiment differs from the fixing system 5 according to the first embodiment (see FIG. 2, etc.) only in that the first duct 61A of the exhaust device 60 is changed to a first duct 61D. The first duct 61D in the third embodiment has the same configuration as the first duct 61A in the first embodiment, except that the introduction section 66 is changed to an introduction section 66C.

[0127] The introduction portion 66C is provided as a plate-like member that protrudes both outward and inward on the upper side 63a of the opening 63. Specifically, the introduction portion 66C is composed of an outer protrusion 66Ca and an inner protrusion 66Cb. The outer protrusion 66Ca is a portion that protrudes obliquely upward from the upper side 63a of the opening 63 to the outside of the duct. The inner protrusion 66Cb is a portion that protrudes obliquely downward from the upper side 63a of the opening 63 to the inside of the duct.

[0128] The introduction portion 66C has a lower surface 66d that is common to the outer protrusion 66Ca and the inner protrusion 66Cb. The lower surface 66d is longer than the lower surface 66c of the introduction portion 66B in the second embodiment by the length of the inner protrusion 66Cb. The angle β formed by the lower surface 66d of the introduction portion 66C and the outer surface of the first side surface portion is substantially the same as the angle β in the first embodiment.

[0129] The outer protrusion 66Ca has a protrusion amount J3, which is the amount by which the lower surface 66d thereof protrudes from the outer surface of the first side surface portion, that is substantially the same as the protrusion amount J2 of the introduction portion 66B in the second embodiment. The inner protrusion 66Cb has a lower surface 66d that protrudes from the first inner wall surface 610a by a predetermined amount M1. The protrusion amount M1 may be set to, for example, a value in the range of 1 / 3 to 1 / 2 of the distance S1 between the first inner wall surface 610a and the second inner wall surface 610b of the raised portion 610Aa.

[0130] <Function of First Duct in Third Embodiment> In first duct 61D, operation of first fan 68A generates a flowing force similar to that in first duct 61A in embodiment 1. This flowing force also appears as an airflow AF as illustrated in FIG.

[0131] Due to this flow force, first, in the first duct 61D, air Ae1, which is part of the air Ae present on the outlet side of the passage FN, is sucked in through the suction port 611A. The sucked air Ae1 then flows upward through the rising portion 610Aa of the first duct 61D.

[0132] Furthermore, the air Ak outside the first duct 61D is also taken in through the opening 63 in the first duct 61D by the above-mentioned flowing force. 9, the air Ak at this time includes a portion of air Ak4 that flows substantially along the lower surface 66d formed by the slope of the introduction portion 66C. This portion of air Ak4 tends to flow toward a portion of the second inner wall surface 610b of the rising portion 610Aa that is slightly above the protruding portion 64. Moreover, due to the presence of the lower surface 66d of the inner protruding portion 68Cb, the air Ak4 at this time tends to flow toward the portion of the second inner wall surface 610b more easily than the air Ak3 in the second embodiment. The air Ak at this time also includes a portion of air Ak2 that flows upward immediately after passing through the opening 63.

[0133] Therefore, while flowing upward in the rising portion 610Aa, the air Ae1 collides with the air Ak2 and Ak4 taken in from the opening 63. In other words, the air Ak2 and Ak4 taken in from the opening 63 collides with the air Ae1 sucked in from the suction port 611A. The collision at this time tends to be intensified because the inner protruding portion 66Cb of the introduction portion 66C is present inside the duct, narrowing the duct passage.

[0134] Due to this collision, the air Ae1 temporarily stagnates and circulates inside the duct, as illustrated by the dashed two-dot line Aes with an arrow in Fig. 9. The air Ae1 at this time also stagnates, being pressed against the protruding portion 64 of the rising portion 610Aa and the second inner wall surface 610b above it. Moreover, if the stagnant air Ae1 contains components such as wax, it will come into contact with the protrusion 64 and the second inner wall surface 610b above it, which will easily generate waste matter 100.

[0135] As a result, in the first duct 61D, the unwanted matter 100 adheres to and aggregates on the protruding portion 64 of the rising portion 610Aa and the second inner wall surface 610b above it. Then, as shown in FIG. 9, the waste material 100 travels down the upper surface 64a, which is the downward slope of the protruding portion 64, and falls from the tip 64e. The fallen waste material 100 falls into the collecting section 65 located almost directly below the protruding section 64 and is collected.

[0136] Therefore, in the fixing system according to the third embodiment, unwanted matter 100 is prevented from falling from suction port 611A of first duct 61D of exhaust device 60 onto recording medium 9 passing through passage FN of fixing device 51.

[0137] Variant. The present invention is not limited to the configurations exemplified as the above-mentioned Embodiments 1 to 3. In other words, the present invention can be modified and altered in various ways without departing from the spirit of the inventions described in the claims. The present invention also includes, for example, the following modifications.

[0138] The fixing system 5 is not limited to being disposed and used inside the housing 10 of the image forming apparatus 1. For example, the fixing system 5 may be disposed and used so as to be connected outside the housing 10.

[0139] Fixing device 51 may use a roller-shaped rotating body equipped with a heating means as first rotating body 53.

[0140] The exhaust device 60 may omit the second duct 61B.

[0141] In the second embodiment, the angle α of the upper surface 64a of the protruding portion 64B may be set to 90 degrees. In this case, the angle α is also the angle perpendicular to the second inner wall surface 610b of the rising portion 610Aa.

[0142] The angle β of the upper surface 66a of the introduction portion 66, the angle β of the lower surface 66c of the introduction portion 66B, and the angle β of the lower surface 66d of the introduction portion 66C may also be set to 90 degrees. In this case, the angle β is also an angle perpendicular to the outer or inner surface of the first side surface of the rising portion 610Aa.

[0143] In the first embodiment, the image forming unit 2 of the image forming apparatus 1 is configured from the image creating unit 20 and the intermediate transfer unit 30 as an example. However, the image forming apparatus 1 of the present invention is not particularly limited in the configuration of the image forming unit 2, and may be an image forming apparatus that requires a fixing unit 50 made up of a fixing system 5. The image forming section 20 is not limited to being composed of four image forming units 20A, 20B, 20C, and 20D. The number of image forming units may be any number other than four, or may be one. The image forming section 2 may not have an intermediate transfer section 30.

[0144] Alternatively, the image forming apparatus 1 may be configured such that the upper housing 10A and the lower housing 10B are separate and independent bodies that are connected together when in use. Furthermore, the image forming apparatus 1 may be configured such that the medium supply unit 40 is separate from the image forming apparatus 1 and is a medium supply device that is connected to the image forming apparatus 1 when in use. Furthermore, the image forming apparatus 1 may be a post-processing device in which the discharge and storage unit also has a function of performing predetermined post-processing on the recording medium 9.

[0145] (Addendum) (((1))) a fixing device having a first rotating body that is heated by a heating means and rotates, and a second rotating body that rotates while contacting the outer circumferential surface of the first rotating body to form a passage portion through which a recording medium on which a toner image is formed passes; a duct that draws in a portion of the air present on the outlet side of the passage through an intake port, flows it upward at least once, and then discharges it to the outside through an exhaust port; and an exhaust device having a fan that draws the air into the duct and generates a force to draw the air out. Equipped with The duct has an opening at a position midway along the upward flow section to take in air from outside the duct, a protrusion that protrudes into the inside of the duct on the inner wall surface opposite the opening, and a collection section at a position below the protrusion that collects unwanted material that is generated inside the duct and falls. (((2))) The fixing system according to (((1))), wherein the opening has an introduction portion that introduces air by causing it to flow in a direction perpendicular to the interior of the duct or in a diagonally downward direction. (((3))) The fixing system according to (((1))) or (((2))), wherein the opening is provided in a position close to the suction port. (((4))) The fixing system described in any one of (((1))) to (((3))), wherein the protrusion is constituted by a plate-shaped member that protrudes and extends in a direction perpendicular to the interior of the duct or in a diagonally downward direction. (((5))) The fixing system according to any one of (((1))) to (((4))), wherein the protrusion is provided at a position lower than the opening. (((6))) The fixing system according to any one of (((1))) to (((5))), wherein the collection section is recessed downward from the suction port. (((7))) The fixing system according to (((6))), wherein the collection unit is provided with an inlet plate extending horizontally from the boundary with the suction port so as to form a lower portion of the suction port. (((8))) an image forming unit that forms a toner image on a recording medium; a fixing unit that heats the toner image formed by the image forming unit to fix it on the recording medium; Equipped with An image forming apparatus in which the fixing unit is configured with the fixing system described in any one of (((1))) to (((7))).

[0146] According to the fixing system of (((1))), it is possible to prevent unwanted matter from falling from the intake port of the duct of the exhaust device onto the recording medium passing through the passage of the fixing device. According to the fixing system of (((2))), it is easier to generate and collect unwanted matter in the upward flow portion of the duct than when the opening does not have an introduction portion. According to the fixing system of (((3))), unwanted matter can be generated and collected at a position close to the suction port. According to the fixing system of (((4))), the waste generated by the protrusion is more likely to fall downward than when the protrusion is composed of a plate-shaped member that extends diagonally upward inside the duct. According to the fixing system of (((5))), unwanted matter is more likely to be generated at the protruding portion than when the protruding portion is provided at a position higher than the opening. According to the fixing system of (((6))), the falling unwanted matter can be collected so as not to leak out of the suction opening. According to the fixing system of (((7))), it is possible to prevent the air sucked in from the suction port from coming into contact with the lower or upper surface of the inlet plate, thereby preventing the generation of unwanted matter, compared to when an inlet plate extending diagonally upward or downward is provided in the collection section. According to the image forming apparatus of (((8))), it is possible to prevent unwanted matter from falling from the intake port of the duct of the exhaust device onto the recording medium passing through the passage of the fixing system. [Explanation of symbols]

[0147] 1...Image forming device 2...Image forming unit 5. Fixing system 9. Recording media 50...Fixing part 53...First rotating body 54A, 54B, 54C…Heating means 55...Second rotating body 60...Exhaust system 61A...First duct (an example of a duct) 63...Opening 64...Protrusion 65...Collection section 66...Introduction 67...Entrance board 68A...First fan (example of a fan) 610Aa...Rising section (an example of a section where the water flows upward at least once) 610b...second inner wall surface (an example of an inner wall surface facing the opening) 611A...suction port 612A…Discharge port FN…passing section Ae: Air present at the exit side of the passage

Claims

1. a fixing device including a first rotating body that is heated by a heating means and rotates, and a second rotating body that rotates while contacting an outer circumferential surface of the first rotating body to form a passage portion through which a recording medium on which a toner image is formed passes; a duct that draws in a portion of the air present on the outlet side of the passage through an intake port, flows it upward at least once, and then discharges it to the outside through an exhaust port; and an exhaust device having a fan that draws the air into the duct and generates a force to draw the air out; Equipped with The duct has an opening at a position midway along the upward flow section to take in air from outside the duct, a protrusion that protrudes into the inside of the duct on the inner wall surface opposite the opening, and a collection section at a position below the protrusion that collects unwanted material that is generated inside the duct and falls.

2. The fixing system according to claim 1 , wherein the opening has an introduction portion that introduces air in a direction perpendicular to or obliquely downward from the inside of the duct.

3. The fixing system according to claim 2 , wherein the opening is provided at a position close to the suction port.

4. The fixing system according to claim 1 , wherein the protruding portion is configured as a plate-like member that extends and protrudes in a direction perpendicular to the interior of the duct or in a diagonally downward direction.

5. The fixing system according to claim 4 , wherein the protrusion is provided at a position lower than the opening.

6. The fixing system according to claim 1 , wherein the collection portion is recessed below the suction port.

7. The fixing system according to claim 6 , wherein the collection section is provided with an inlet plate extending horizontally from a boundary with the suction port so as to form a lower portion of the suction port.

8. an image forming unit that forms a toner image on a recording medium; a fixing unit that heats the toner image formed by the image forming unit to fix it on the recording medium; Equipped with An image forming apparatus, wherein the fixing unit is configured with the fixing system according to claim 1 .

Images