Image forming apparatus

Abstract

This generates different airflows in different sections of the duct. [Solution] The image forming apparatus is equipped with a pair of exhaust ducts 101-107 and 204-205, each having intake openings located at different points. The pair of exhaust ducts are each provided with exhaust fans 110 and 210, and share an exhaust port 300 and a filter 301 provided at the exhaust port. The pair of ducts are an exhaust duct for the fixing member 27 of the fixing apparatus and an exhaust duct for the drive unit of the fixing apparatus, or the drive unit of the conveying device for the recording sheet that is conveyed through the fixing apparatus.

Description

【Technical Field】 【0001】 The present invention relates to an image forming apparatus. 【Background Art】 【0002】 Conventionally, an image forming apparatus provided with an exhaust fan in an exhaust duct is known. For example, in Patent Document 1, such an image forming apparatus includes a fixing unit that heats and fixes a toner image transferred to a recording medium and a first duct disposed adjacent thereto, and an exhaust fan that discharges the air in the first duct to the outside of the apparatus main body, and the inside of the first duct is described as being divided into a plurality of air flow paths. 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0003】 However, there is no mention of generating different airflows in different duct portions. 【Means for Solving the Problems】 【0004】 The image forming apparatus of the present invention includes a pair of exhaust ducts in which intake openings are arranged at different locations, exhaust fans are provided in each of the pair of exhaust ducts, and an exhaust port and a filter provided at the exhaust port are shared with each other. 【Effects of the Invention】 【0005】 According to the present invention, different airflows can be generated in different duct portions. 【Brief Description of the Drawings】 【0006】 [Figure 1] Schematic configuration diagram of the image forming apparatus. [Figure 2] Perspective explanatory view of the airflow configuration mechanism. [Figure 3] Plan view of the same airflow configuration mechanism. [Figure 4]Front view diagram illustrating the airflow configuration mechanism. [Figure 5] A magnified explanatory diagram of a portion of Figure 3. [Figure 6] A schematic diagram of the airflow configuration mechanism. [Modes for carrying out the invention] 【0007】 An embodiment of the present invention applied to an electrophotographic copier as an image forming apparatus will be described. First, the outline of this copier will be described using Figure 1. In Figure 1, the copier is a tandem electrophotographic apparatus that forms an image on a recording sheet using an intermediate transfer method with an intermediate transfer belt 11, and also forms toner images of each color using dedicated process cartridges. At the bottom of the copier in the vertical direction, a multi-stage paper feeding section 2 is provided. Above that, an image forming section 1 is provided, and further above that, a scanner section 3 is provided. Each stage of the paper feeding section 2 is equipped with a paper feeding tray 21 that accommodates a bundle of sheets consisting of recording materials such as plain paper, OHP sheets, and second original drawings. 【0008】 A transfer device 10 is located near the center of the image forming unit 1, with an endless intermediate transfer belt 11 stretched across it by multiple rollers. The intermediate transfer belt 11 rotates (moves across its surface) in a clockwise direction in the figure. Above the intermediate transfer belt 11, along the direction of surface movement of the intermediate transfer belt 11, are four process cartridges 40Y, 40M, 40C, and 40K for creating yellow, magenta, cyan, and black toner images. Hereafter, the color coding codes Y, M, C, and K will be omitted as appropriate. Above the four process cartridges 40, two optical writing units 20a and 20b are provided as latent image writing means. 【0009】 Each process cartridge 40 is provided with a drum-shaped photoreceptor 41 as a latent image carrier. Each photoreceptor 41 is rotatable in a counterclockwise direction in the figure, and a known charging device 42, developing device 43, photoreceptor cleaning device 44, and lubricant application device 45 are provided around it. 【0010】 In Figure 1, the transfer device 10 includes an intermediate transfer belt 11, a belt cleaning device 17, and four primary transfer rollers 46. The intermediate transfer belt 11 is tensioned by multiple rollers, including a tension roller 14, a drive roller 15, and a secondary transfer opposing roller 16. The belt is then moved endlessly clockwise in the figure by the rotation of the drive roller 15, which is driven by a belt drive motor. 【0011】 The four primary transfer rollers 46 are each positioned to contact the inner circumferential surface of the intermediate transfer belt 11 and receive primary transfer bias from the power supply. They also press the intermediate transfer belt 11 from its inner circumferential surface toward the photoreceptor 41, forming primary transfer nips. 【0012】 Furthermore, the transfer device 10 has a secondary transfer roller 22, which constitutes a secondary transfer means, located below the intermediate transfer belt 11. This secondary transfer roller 22 is positioned to press against the secondary transfer opposing roller 16 via the intermediate transfer belt 11. Downstream of the intermediate transfer belt 11 surface movement direction from the secondary transfer opposing roller 16, a belt cleaning device 17 is provided. The belt cleaning device 17 includes a rotationally driven belt cleaning brush roller 17a and a brush roller 17b of a lubricant application mechanism. 【0013】 Downstream of the secondary transfer roller 22 in the paper transport direction, a fixing device 25 is provided to fix the toner image formed on the recording sheet to the sheet surface. A pressure roller 27 is pressed against an endless fixing belt 26. After image transfer, the recording sheet is transported to the fixing device 25 by an endless transport belt 24 stretched between a pair of rollers 23. Below the secondary transfer roller 22, a sheet reversing device 28 is provided to invert the sheet when forming images on both the front and back surfaces of the sheet. The sheet reversing device 28 is equipped with transport rollers 28a, etc. 【0014】 When making a color copy of an original document with a copier having the above configuration, the scanner unit 3 reads the image of the original document set on the contact glass. The intermediate transfer belt 11 is rotated to form toner images on each photoreceptor 41 by a known image forming process. Next, the toner images formed on each photoreceptor are sequentially superimposed and transferred to the intermediate transfer belt 11 to form a four-color superimposed toner image on the intermediate transfer belt 11. 【0015】 Meanwhile, in parallel with the image formation operation of the four-color superimposed toner image on the intermediate transfer belt 11, recording sheets are separated and fed one by one from the selected paper tray 21 of the paper feeding unit 2 and transported toward the registration roller 29. The registration roller 29 is rotated at a timed interval to set the positional relationship between the four-color superimposed toner image formed on the intermediate transfer belt 11 and the leading edge of the recording sheet to a predetermined position. As a result, the four-color superimposed toner image on the intermediate transfer belt 11 is secondarily transferred to this predetermined position on the recording sheet by the secondary transfer roller 22, forming a full-color toner image on the recording sheet. 【0016】 The recording sheet on which the full-color toner image has been formed is fed to the fuser 25, which is located downstream of the secondary transfer roller 22 in the transport path. This fuser 25 fixes the full-color toner image that has been secondarily transferred by the secondary transfer roller 22 onto the recording sheet. The recording sheet on which the full-color toner image has been fixed is discharged to the outside of the device by the paper discharge roller 30. In the double-sided printing mode, where an image is formed on both sides of the recording sheet, the recording sheet with the full-color toner image fixed only on the first side is discharged from the fuser 25 and sent to the sheet inversion device 28. After being inverted on both sides by the sheet inversion device 28, it is transported again to the register roller 29. Subsequently, by passing through the secondary transfer roller 22 and the fuser 25, a full-color image is also formed on the second side. 【0017】 The copying machine of this embodiment includes an airflow configuration mechanism 300 that suppresses the amount of fine particles generated from the fixing device 25 and its peripheral components from being discharged outside the machine. This airflow configuration mechanism 300 includes an exhaust duct for cooling the pressure roller 27 of the fixing device 25 (hereinafter referred to as the roller cooling exhaust duct), and a drive unit exhaust duct including the drive unit of the pressure roller 27 or the drive unit of the conveying device through which the recording sheet passing through the pressure roller 27 in the housing is conveyed. Each of the outlets of these two exhaust ducts has a fan, and the exhaust from these outlets is exhausted outside the machine through one filter. 【0018】 FIG. 2 is a perspective explanatory view of the airflow configuration mechanism 300, FIG. 3 is a plan view of the airflow configuration mechanism 300, FIG. 4 is a front explanatory view of the airflow configuration mechanism 300, and FIG. 5 is a partial enlarged explanatory view in FIG. 3. As shown in FIGS. 3 and 4, the roller cooling exhaust duct of the pressure roller 27 is composed of ducts 101 to 107 whose interiors for flowing airflows A1 to A6 are in communication. Air is sent into the first-stage duct 101 from a sirocco fan 100 that can be either a double-sided suction type or a single-sided suction type. The final-stage duct 107 is connected to a fan 110. 【0019】 The drive unit exhaust duct is composed of ducts 204 and 205 whose interiors for receiving the air that has passed through the drive unit as airflows B1 to B2 and is received by the airflow receiving member 203 and flowing as airflows B4 to B5 are in communication. The first-stage duct 204 receives airflow B3 from the airflow receiving member 203 through an opening 204c. The final-stage duct 205 is connected to a fan 210. 【0020】 Then, the airflow A7 discharged from the fan 110 of the roller cooling exhaust duct and the airflow B6 discharged from the fan 210 of the drive unit exhaust duct are discharged from the common airflow configuration mechanism 300, and a common filter 301 is provided in this airflow configuration mechanism 300. 【0021】 As shown in FIGS. 2 and 3, the drive unit exhaust duct receives and guides the airflows B1 and B2 that have passed through the drive unit arranged on the rear side of the apparatus. In the illustrated example, there are drive transmission parts to the gear 27a for receiving drive on the rear side of the apparatus of the pressure roller 27 and drive parts on the rear side of the apparatus to the conveyance roller 28a. In the figure, the conveyance roller 28a is driven by transmission of drive from the drive pulley 28b via the timing belt 28c. If grease is used for these gears 27a and the timing belt, fine particles are generated and the roller cooling exhaust duct alone cannot completely capture the fine particles. 【0022】 In the present embodiment, an air containing fine particles generated in the drive unit is captured by a drive unit cooling exhaust duct provided separately from the roller cooling exhaust duct, and the air from which the fine particles have been removed by the filter 301 is discharged outside the apparatus, so that the discharge of fine particles generated in the drive unit to the outside of the apparatus can be suppressed. 【0023】 Moreover, as shown in FIG. 5, the duct 204 provided with the opening 204c has the upper opening in FIG. 5 of the resin duct member 204a closed by the metal plate 204b (see FIG. 2), and the metal plate 204b and the resin duct member 204a are connected by screwing or the like. This resin duct member 204a is inclined at an angle θ of 1 to 5° with respect to the perpendicular line 6B to the virtual opening plane 6A of the opening 204c, that is, the surface on the parting line side of the resin duct member 204a, namely, the combined surface of the resin duct member 204a and the metal plate 204b. 【0024】 According to this, unlike the case where a sudden change in the angle of the flow path (bend) occurs inside, there is no situation where the pressure loss increases or the convection becomes violent. Therefore, even when installed in a narrow space, the pressure loss can be minimized. For example, even in a narrow space where other components are present and it is necessary to avoid them, the other components can be avoided with a gentle slope to reduce the pressure loss. 【0025】 Figure 6 schematically shows the airflow configuration mechanism 300 of this embodiment. Each fan 110 and 210 is driven by an independent motor M1 and M2, respectively. Reference numeral 353 indicates a control unit that controls the drive of each motor. The fan 110 of the roller cooling exhaust duct is also subject to driving constraints from the viewpoint of temperature control of the fixing device 25 using a temperature sensor 354. 【0026】 Conventional exhaust systems for reducing particulate matter exhaust use a known technique of using a fixing cooling roller duct to expel particulate matter generated from the roller inside the pressure roller 27 to the outside of the machine while simultaneously cooling the roller. In a system where a fan that also cools the fixing pressure roller sucks in particulate matter and expels it to the outside of the machine via a filter, the fixing temperature control is dominant, so it is not possible to constantly collect particulate matter inside the machine, and there is a risk that particulate matter accumulated inside the machine will leak out of the machine through an exhaust port that is not the intended location. If only a duct that serves both to cool the fixing pressure roller and to exhaust particulate matter is used, particulate matter generated from the grease of the drive gear cannot be collected, and particulate matter will leak out of the machine. 【0027】 In contrast, in this embodiment, the roller cooling exhaust duct is provided with an independent fan in a separate exhaust duct for the drive unit. This allows for independent fan drive control from the fixing unit, and enables the collection of fine particles generated around the fixing drive with a constant airflow, unaffected by the fixing temperature control. 【0028】 Furthermore, by exhausting the collected fine particles through the same filter installed at the exhaust port of the roller cooling duct, the filters become soiled at the same rate, allowing them to be replaced at the same time, minimizing work efficiency and costs. 【0029】 Although preferred embodiments of the present invention have been described above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the spirit of the present invention as described in the claims, unless otherwise specifically limited in the above description. [Explanation of symbols] 【0030】 1: Image forming unit 2:Paper feed section 3: Scanner section 6A:Aperture plane 6B: Perpendicular line 10: Transfer device 11: Intermediate transfer belt 14: Tensioning roller 15: Drive roller 16: Secondary transfer opposing roller 17: Belt cleaning device 17a: Belt cleaning brush roller 17b: Brush roller 20a: Optical writing unit 20b: Optical writing unit 21: Paper feed tray 22: Secondary transfer roller 23: Laura 24: Conveyor belt 25: Fixing device 26: Fixing belt 27: Pressure roller 27a: Gear 28: Sheet reversal device 28a: Conveyor roller 28b: Drive pulley 28c: Timing belt 29: Registroller 30: Paper output roller 40: Process cartridge 40C: Process cartridge 40K: Process cartridge 40M: Process Cartridge 40Y: Process cartridge 41: Photoreceptor 42: Charging device 43: Developing equipment 44: Photoconductor cleaning device 45: Lubricant application device 46: Primary transfer roller 100: Sirocco fan 101: Duct 102: Duct 103: Duct 104: Duct 105: Duct 106: Duct 107: Duct 110: Fan 203: Airflow receiving member 204: Duct 204a: Duct components 204b: Metal plate 204c :Aperture 205: Duct 210: Fan 300: Airflow configuration mechanism 301: Filter 354: Temperature sensor [Prior art documents] [Patent Documents] 【0031】 [Patent Document 1] Japanese Patent Publication No. 2019-117275

Claims

[Claim 1] An image forming apparatus characterized by having a pair of exhaust ducts with intake openings located at different positions from each other, each exhaust duct being equipped with an exhaust fan, and the exhaust ports and filters provided at the exhaust ports being shared between them. [Claim 2] In the image forming apparatus according to claim 1, The image forming apparatus is characterized in that the pair of ducts are an exhaust duct for a fixing member of the fixing device and an exhaust duct for the drive unit of the fixing device or the drive unit of a conveying device for a recording sheet that is conveyed through the fixing device. [Claim 3] In the image forming apparatus according to claim 1 or 2, At least one of the pair of exhaust ducts has a structure in which the opening of a resin duct member is sealed with a plate member made of metal or the like. An image forming apparatus characterized in that the joined surfaces of the plate members in the resin duct member are inclined at an angle of 1 to 5° with respect to a perpendicular line to the virtual opening plane of the air intake.

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