JP7110028B2 - image forming device - Google Patents

Description

The present invention relates to image forming apparatuses such as copiers and printers.

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, it is known that fine particles are emitted when heat is applied to a component contained in wax of a fixing member or toner. These fine particles are called ultrafine particles (UFP), which are different from ozone and toner dust, and the reduction of the amount of ultrafine particles emitted is a problem.

In Patent Literature 1, a box portion arranged along the exterior surface of the device main body and a duct portion covering the exhaust port of the device main body are provided. The box body includes a filter chamber for housing the filter so as to face the main body of the device, a first ventilation portion for allowing the exhaust gas to flow into the filter chamber from the duct portion, and a second ventilation portion for discharging the exhaust gas from the filter chamber to the outside. are provided. The first ventilation part and the second ventilation part are located on opposite sides of the center of area of the filter when viewed from the rear side of the apparatus main body.

JP 2017-32833 A

In Patent Document 1, a filter is arranged immediately after the exhaust port of the apparatus main body. Further, dust has a property that solidification is accelerated by cooling and the size increases. Therefore, if the filter is arranged immediately after the exhaust port of the apparatus main body, the air containing dust will pass through the filter in a high temperature state. Therefore, it is necessary to use a fine filter.

However, using a fine-mesh filter increases pressure loss due to the filter, and requires the use of a powerful fan in order to sufficiently dissipate the heat within the apparatus body. As a result, the operation noise of the entire image forming apparatus becomes louder, and the power consumption also increases. In other words, reducing the pressure loss due to the filter leads to a reduction in noise and power consumption of the entire image forming apparatus.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that collects generated dust and achieves both low noise and low power consumption.

A representative configuration of the image forming apparatus according to the present invention for achieving the above object is an image forming apparatus that forms an image by heating a toner image transferred onto a recording material in a fixing section and fixing the toner image onto the recording material. a first exhaust port for discharging the air warmed by the fixing section to the outside of the apparatus main body; and a second exhaust port provided at the downstream end of the duct in the air flow direction for exhausting the air exhausted from the first exhaust port to the outside. a filter provided on an exhaust path between the first exhaust port and the second exhaust port inside the duct for collecting dust ; a first fan for generating an airflow to be taken into the duct; and a fan provided inside the duct for discharging the air taken into the duct from the first exhaust port through the second exhaust port. and a second fan for generating an airflow , wherein the filter is configured such that exposure of the duct to ambient air results in a first temperature of the air at the duct inlet and a temperature of the air passing through the filter. provided at a position where a temperature difference from a second temperature lower than the first temperature becomes a predetermined temperature difference, and the duct comprises a first duct and a second duct connected to the first duct; and a duct, wherein the center line of the first duct and the center line of the second fan do not overlap .

According to the present invention, it is possible to achieve both noise reduction and low power consumption while collecting generated dust.

1 is a schematic cross-sectional view of an image forming apparatus; FIG. 2 is a schematic cross-sectional view of a fixing device; FIG. 3 is a schematic diagram of a fixing device, a fan, and a cooling duct; FIG. 3 is an explanatory diagram of the inside of the image forming apparatus; FIG. 5 is a graph for explaining fan drive timing; 2 is a perspective view of the image forming apparatus as seen from the back side; FIG. FIG. 4 is a schematic diagram of a duct unit; 4 is a perspective view of the duct unit; FIG. 4 is a perspective view of the duct unit; FIG. 4 is a cross-sectional view of the duct unit; FIG. 4 is a cross-sectional view of the duct unit; FIG. 4 is a cross-sectional view of the duct unit; FIG. It is a perspective view of a lower unit. It is a perspective view of a lower unit. It is a sectional view of a lower unit. 4 is a graph showing the temperature distribution inside the duct of the duct unit; 5 is a graph showing the relationship between the flow rate of air supplied from an air supply port of a duct in a duct unit, the flow rate of air exhausted from a duct exhaust port, and the internal temperature of an image forming apparatus. 2 is a layout diagram of a duct unit and an electrical system unit when the image forming apparatus is viewed from the rear side; FIG.

(First embodiment)
<Image forming apparatus>
Hereinafter, first, the overall configuration of the image forming apparatus according to the first embodiment of the present invention will be described together with the operation during image formation with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative positions, etc. of the described components are not meant to limit the scope of the present invention only to them, unless otherwise specified.

FIG. 1 is a schematic cross-sectional view of an image forming apparatus H according to this embodiment. As shown in FIG. 1, the image forming apparatus H is an electrophotographic image forming apparatus that forms an image on a sheet using four color toners of yellow, magenta, cyan, and black. The image forming apparatus H includes an image forming section that transfers a toner image onto a sheet to form an image, a sheet feeding section that feeds the sheet toward the image forming section, and a fixing section that fixes the toner image onto the sheet. .

The image forming section includes process units 103 (103Y, 103M, 103C, 103K) that form toner images of the respective colors using the toners of the respective colors. It also has an exposure device 104 (104Y, 104M, 104C, 104K), an intermediate transfer belt 6, a secondary transfer roller 8, a secondary transfer opposing roller 9, and the like.

Each process unit 103 includes a photosensitive drum 3 , a charging roller 4 , a developing device having a developing sleeve 5 , and a primary transfer roller 7 . Note that the process units 103Y, 103M, 103C, and 103K use yellow, magenta, cyan, and black toners, respectively, and the configuration other than the colors of toners used is the same for each process unit.

Next, the image forming operation will be described. First, when the controller board 120 shown in FIG. 18 receives an image forming job signal, the sheets S (recording material) stacked and accommodated in the sheet cassette 101 are sent to the registration rollers 12 by the pickup roller 2, the feeding roller 10, and the conveying roller 11. be Next, the sheet S is subjected to skew correction and timing correction by the registration rollers 12 , and then sent to the secondary transfer portion formed by the secondary transfer roller 8 and the secondary transfer opposing roller 9 .

On the other hand, in the image forming section, the charging roller 4 first charges the surface of the photosensitive drum 3 . Thereafter, image data transmitted from an external device (not shown) is processed by the controller board 120, and the exposure device 104 irradiates the surface of the photosensitive drum 3 of each color with laser light according to the processing result. As a result, an electrostatic latent image corresponding to the image data is formed on the surface of the photosensitive drum 3 .

After that, toner of each color is applied to the electrostatic latent image formed on the surface of the photosensitive drum 3 by the developing sleeve 5 to form a toner image on the surface of the photosensitive drum 3 . The toner images formed on the surface of the photosensitive drum 3 are primarily transferred to the intermediate transfer belt 6 by applying a primary transfer bias to the primary transfer roller 7 . As a result, a full-color toner image is formed on the intermediate transfer belt 6 surface.

After that, when the secondary transfer counter roller 9 receives a driving force from a drive source (not shown) and rotates, the intermediate transfer belt 6 is driven to rotate, and the toner image is sent to the secondary transfer portion. Then, the toner image on the intermediate transfer belt 6 is transferred onto the sheet S by applying a secondary transfer bias to the secondary transfer roller 8 in the secondary transfer portion.

Next, the sheet S onto which the toner image has been transferred is conveyed to the fixing device 50 . The fixing device 50 includes, as a fixing section, a fixing belt 20 including a heater 16 (FIG. 2), and an actuator that applies pressure to the fixing belt 20 and rotates by driving force of a drive source (not shown) to rotate the fixing belt 20 in a driven manner. A pressure roller 22 is provided.

The sheet S conveyed to the fixing device 50 is nipped and conveyed in a fixing nip portion N formed by the fixing belt 20 and the pressure roller 22 and subjected to heat and pressure processing, thereby forming a toner image on the sheet S. is fixed on the sheet S. After that, the sheet S on which the toner image is fixed is discharged to the discharge tray 106 by the discharge rollers 70 .

In this embodiment, the toner contains paraffin wax, and the wax melted by the heat of the fixing process is interposed at the interface between the fixing belt 20 and the toner image so that the toner does not adhere to the fixing belt 20. there is The melting point of this wax is about 75.degree. C., and the target temperature of the fixing nip portion is 170.degree.

Waxes are not limited to those described above, and compounds containing wax molecular structures, such as wax molecular structures such as hydrocarbon chains reacted with toner resin molecules, can also be used. Also, instead of wax, it is also possible to use other substances having a release action, such as silicon oil.

When images are formed on both sides of the sheet S, the sheet S is led to the reversing path 13 after the toner image is fixed on the surface thereof by the fixing device 50 . After that, the reversing roller 14 rotates in the opposite direction while holding the sheet S therebetween, and the sheet S is re-supplied through the re-feeding path 15 so that the front and back surfaces are reversed, and then sent to the secondary transfer portion again. Next, an image is formed on the back surface of the sheet S in the same manner as the front surface of the sheet S, and then the sheet S is discharged to the discharge tray 106 .

Here, the image forming apparatus H can be equipped with a sheet processing apparatus (not shown) that performs binding processing, folding processing, and the like on the sheets S on which images have been formed by the image forming section. In the image forming apparatus H of this embodiment, the sheet processing apparatus is connected to the left side in FIG. 1 via a relay unit (not shown) or the like. That is, the sheet processing apparatus is mounted on the opposite side of the image forming apparatus H from the fixing device 50 in the horizontal direction (width direction) of the image forming apparatus H. As shown in FIG.

<Fixing device>
Next, the configuration of the fixing device 50 will be described.

FIG. 2 is a schematic cross-sectional view of the fixing device 50. As shown in FIG. As shown in FIG. 2 , the fixing device 50 includes a fixing belt 20 , a pressure roller 22 , a heater 16 that generates heat when energized, and a heater holder 17 that holds the heater 16 . It also has a guide member 23 , a fixing discharge roller 26 , a main thermistor 19 and a sub-thermistor 18 .

The pressure roller 22 is formed by forming a silicone rubber layer with a thickness of about 3 mm on a stainless steel core by injection molding, and covering it with a PFA resin tube with a thickness of about 40 μm. The pressing roller 22 is rotatably held by bearings (not shown) attached to the frame 24 at both ends of a cored bar, and is rotated by the driving force of a driving source (not shown).

The fixing belt 20 is an endless cylindrical member, and is loosely fitted around the heater holder 17 . The heater holder 17 is urged toward the pressure roller 22 with a force of 98N on one side and a total of 196N by an urging mechanism (not shown) at both ends of the pressure roller 22 in the rotation axis direction. As a result, the heater 16 is brought into pressure contact with the pressure roller 22 via the fixing belt 20, and the fixing nip portion N is formed. Note that the biasing mechanism is configured so that the biasing can be released in order to remove the sheet S during jam processing.

When the pressure roller 22 rotates, the fixing belt 20 in contact with the pressure roller 22 is driven to rotate around the heater holder 17 while the inner peripheral surface of the fixing belt 20 contacts and slides on the heater 16 due to frictional force. In order to ensure slidability between the heater holder 17 and the inner peripheral surface of the fixing belt 20, the inner peripheral surface of the fixing belt 20 is coated with grease.

A main thermistor 19 is provided in contact with the back surface of the heater 16 and detects the temperature of the heater 16 . The sub-thermistor 18 is provided in elastic contact with the inner circumferential surface of the fixing belt 20 and detects the temperature of the fixing belt 20 . These main thermistor 19 and sub-thermistor 18 are connected to the CPU 21 via an A/D converter (not shown). The CPU 21 controls energization of the heater 16 by the heater driving circuit 28 based on the outputs of the main thermistor 19 and the sub-thermistor 18, and controls the temperature of the heater 16. FIG. The main thermistor 19 is arranged near the center of the heater 16 in the longitudinal direction. The sub-thermistor 18 is provided near the longitudinal end of the fixing belt 20 .

The guide member 23 guides the sheet S to the fixing nip portion N by contacting the sheet S. As shown in FIG. The guide member 23 is made of polyphenylene sulfide (PPS) resin in this embodiment.

When performing the fixing process, the sheet S carrying an unfixed toner image is introduced into the fixing nip portion N first. Next, at the fixing nip portion N, the sheet S is nipped and conveyed while the toner image bearing surface thereof is brought into contact with the outer circumferential surface of the fixing belt 20 . In this conveying process, the heat of the heater 16 is applied to the toner image on the sheet S through the fixing belt 20, and the unfixed toner image is melted and fixed on the sheet S. FIG. After that, the sheet S that has passed through the fixing nip portion N is curvedly separated from the fixing belt 20 and conveyed to the discharge roller 70 side by the fixing paper discharge roller 26 .

<Cooling unit>
Next, the cooling section that cools the fixing nip portion N will be described.

When the sheet S conveyed to the fixing device 50 is large, the sheet S passes through substantially the entire width of the fixing nip portion N in the sheet width direction perpendicular to the conveying direction of the sheet S. As a result, the heat in substantially the entire fixing nip portion N is absorbed by the sheet S, and the temperature of the fixing nip portion N becomes substantially constant in the sheet width direction.

On the other hand, when the sheet S conveyed to the fixing device 50 is small, the sheet S passes through the fixing nip portion N only near the center in the sheet width direction. Therefore, in the fixing nip portion N, the heat near the center in the sheet width direction is taken away by the sheet S, but the heat at both ends is not taken away, and the temperature at both ends becomes higher than the temperature near the center.

In this case, if the temperature of the heater 16 is raised in order to maintain fixability at the central portion, the temperature at the central portion reaches the desired temperature, but the temperature at the both ends continues to rise, which adversely affects the fixing device 50, such as deformation of members. may cause Therefore, the image forming apparatus H is provided with fans 95 and 96 and a cooling duct 30 as cooling units for cooling the fixing nip portion N in order to suppress temperature rise at both end portions of the fixing nip portion N in the sheet width direction.

FIG. 3 is a schematic diagram of the fixing device 50, the fans 95 and 96, and the cooling duct 30. As shown in FIG. FIG. 4 is an explanatory view of the inside of the image forming apparatus H, and is a perspective view of a state in which a part of the exterior of the apparatus body is made transparent. FIG. 5 is a graph for explaining drive timings of the fans 95 and 96. FIG.

As shown in FIGS. 3 to 5, two fans 95 and 96 for cooling the fixing belt 20 and a cooling duct 30 are provided at both ends of the fixing belt 20 in the rotation axis direction. The cooling ducts 30 are located at both ends of the fixing belt 20, and supply air to non-passing regions of the fixing belt 20 through which the small-sized sheet S does not pass when the fixing device 50 performs the fixing process on the small-sized sheet S. invite. The fans 95 and 96 are turned on when the temperature detected by the sub-thermistor 18 is above a predetermined temperature, and turned off when the temperature is below a predetermined temperature.

With such a configuration, it is possible to suppress the temperature rise of the non-passing area when the small-sized sheets S are continuously subjected to the fixing process. In this embodiment, centrifugal fans such as sirocco fans are used as the fans 95 and 96, but it is also possible to use other types of fans.

<Summary of duct unit>
Next, an overview of the duct unit 200 that removes dust from the air exhausted from the image forming apparatus H will be described. The image forming apparatus H has a duct unit 200 attached to the apparatus main body 1 . An upper cover 111 and a lower cover 112 as exterior covers are provided on the back side of the apparatus main body 1 , and the duct unit 200 is attached to the apparatus main body 1 through the upper cover 111 and the lower cover 112 . The duct unit 200 forms a flow path for discharging air warmed by the fixing device 50 to the outside of the apparatus body 1 .

As described above, when heat is applied to the toner image on the sheet S for fixing processing in the fixing device 50, part of the wax contained in the toner is vaporized, and the vaporized wax is cooled in the air. It condenses into dusty air. Research by the present inventors has revealed that most of this dust adheres to the vicinity of the sheet introduction port 400 of the fixing device 50, and that the dust tends to adhere to the vicinity of the sheet introduction port 400 due to its large particle size, especially in a high-temperature environment. ing.

Here, the BLUE ANGEL standard in Europe stipulates a standard for the amount of ultrafine particles (ULTRA FINE PARTICLES) discharged, and the image forming apparatus H is also desired to reduce the amount of ultrafine particles discharged. Therefore, the image forming apparatus H is equipped with the duct unit 200 to remove dust from the air heated by the fixing device 50 .

FIG. 6 is a perspective view of the image forming apparatus H viewed from the rear side. As shown in FIG. 6, a duct unit 200 is provided on the exterior of the image forming apparatus H so as to protrude rearward. The duct unit 200 is composed of an upper unit 220 having an upper duct 224 and a lower unit 240 having a lower duct 241 connected to the upper duct 224 .

FIG. 7 is a schematic diagram of the duct unit 200. As shown in FIG. As shown in FIG. 7A, a fan 91 (first fan) and a fan 92 (second fan) for exhausting heat are provided near the fixing device 50 . Fans 91 and 92 are held by fan holders 280, and fan holders 280 are fastened to rear side plate 80 (FIG. 4).

Further, the fan 91 exhausts the air around the fixing device 50 . The fan 92 is arranged near the conveying path of the sheet S above the fan 91 (on the downstream side in the sheet conveying direction), and exhausts the air around the discharge section 75 to the outside of the apparatus. The discharge section 75 is a space above the fixing device 50 and a space around the discharge roller 70 . The fan 91 and the fan 92 are provided on the rear side of the image forming apparatus H with respect to the rear plate 80 (FIG. 4).

Air containing dust generated in the fixing device 50 is exhausted from the exhaust port 227 of the apparatus main body 1 by the airflow generated by the fan 91 and carried into the upper duct 224 through the air supply port 230 of the upper duct 224 . Air containing dust carried upward by natural convection is exhausted from the exhaust port 228 of the apparatus main body 1 by the airflow generated by the fan 92 and carried into the upper duct 224 through the air supply port 231 of the upper duct 224 .

The upper duct 224 has two air inlets 230,231. An inner duct 233 is provided on the inner surface of the cover member 225 to guide the air exhausted from the inside of the apparatus main body 1 through the respective air supply ports 230 and 231 . Further, the inner duct 233 and the lower duct 241 of the lower unit 240 are connected to each other, and the outer duct 226 guides the air exhausted from the apparatus body 1 to the lower unit 240 via the inner duct 233 .

The air exhausted from the exhaust ports 227 and 228 is separated by a partition wall portion 229a that is a part of the inner duct 233, then joins at a confluence portion 229b, and is carried to the lower duct 241 via the outer duct 226. . That is, a partition wall portion 229a that separates the air supplied from the air supply port 230 and the air supplied from the air supply port 231 is provided upstream of the confluence portion 229b in the air flow direction.

The air carried to the lower duct 241 is carried to the duct exhaust port 244 (second exhaust port) side by the airflow generated by the fan 102 . After the dust is collected by a filter 260 provided on the exhaust path between the exhaust ports 227 and 228 and the duct exhaust port 244 , the dust is exhausted to the outside of the image forming apparatus H through the duct exhaust port 244 .

Thus, the filter 260 is arranged downstream in the air flow direction of the confluence portion 229b where the air supplied from the air supply port 230 and the air supplied from the air supply port 231 join. As a result, compared to a configuration in which the air merges in the filter 260, the area of the surface entering the filter 260 can be reduced and the size of the filter 260 can be reduced.

Further, as shown in FIG. 7B, by arranging the center line L1 of the fan 102 and the center line L2 of the upper duct 224 not to overlap each other, the air in the lower duct 241 is made to flow in the radial direction, The dust can be efficiently collected by passing through a wide range of 260.

<Detailed configuration of the duct unit>
Next, a detailed configuration of the duct unit 200 will be described.

8 and 9 are perspective views of the duct unit 200. FIG. 10 and 11 are cross-sectional views of the duct unit 200 taken along the LL cross section shown in FIG. 8 and the HH cross section shown in FIG. 9, respectively. FIG. 12 is a cross-sectional view of the duct unit 200 taken along the JJ cross section shown in FIG. 8 and 10 are diagrams showing the case where the upper unit 220 is closed, and FIGS. 9, 11 and 12 are diagrams showing the case where the upper unit 220 is open.

As shown in FIGS. 8 to 12, the upper unit 220 has shafts 221a and 221b. The shafts 221 a and 221 b are coaxially arranged and inserted into holes (not shown) formed in the upper cover 111 that is the exterior of the apparatus main body 1 of the image forming apparatus H. As shown in FIG. Accordingly, the upper unit 220 is rotatably supported by the upper cover 111 about the shaft portions 221a and 221b, and opens and closes with respect to the apparatus body 1 of the image forming apparatus H by rotating. Further, the opening/closing sensor 25 as a detection means detects that the upper unit 220 is in the open state with respect to the apparatus main body 1 .

Also, the upper unit 220 is composed of a cover member 225 forming an exterior cover and an upper duct 224 provided inside the cover member 225 . The cover member 225 serves as an opening/closing cover for exposing the user interface 130 such as the LAN cable connection portion 122 and the HDD insertion portion 121a provided on the apparatus main body 1 side facing the cover member 225 .

Here, in the image forming apparatus H of the present embodiment, the user interface 130 is arranged on the rear side of the apparatus main body 1 and on the side opposite to the side on which the sheet processing apparatus is mounted in the horizontal direction, that is, on the side of the fixing device 50 . ing.

A hard disk drive 121 (hereinafter referred to as HDD 121: Hard Disk Drive) can be inserted into and removed from the HDD insertion portion 121a. That is, when the upper unit 220 is closed, the user interface 130 provided on the apparatus main body 1 is provided at a position covered by the inner duct 233 of the duct unit 200 . Therefore, when the upper unit 220 is opened, the user interface 130 can be accessed, and the HDD 121 can be inserted/extracted and a LAN cable (not shown) can be connected.

A sheet metal 223 for magnet catch is provided on the cover member 225 , and a magnet catch 222 is provided on a portion of the upper cover 111 facing the sheet metal 223 . The cover member 225 is configured to be attracted to the apparatus main body 1 side (apparatus main body side) by a magnet catch 222 .

The magnet catch 222 urges the cover member 225 in a closing direction by a magnetic force via the metal plate 223, attracts the metal plate 223, and holds the cover member 225 in the closed state. That is, the upper unit 220 is held closed by the magnetic force of the magnet catch 222 . In this embodiment, the magnet catch 222 is used to keep the upper unit 220 closed, but other biasing means may be used to bias the upper unit 220 in the closing direction.

When the upper unit 220 is closed, the air supply port 230 is connected to the exhaust port 227 through which the air in the apparatus main body 1 is discharged by the fan 91 , and the air supply port 231 is connected to the air in the apparatus main body 1 by the fan 92 . It is connected with the exhaust port 228 to be discharged. Also, the outer duct 226 of the upper duct 224 is connected to a lower duct 241 provided in the lower unit 240 .

That is, the inner duct 233 as a first duct is provided so as to be openable and closable with respect to the apparatus main body 1 . When the upper unit 220 is closed with respect to the apparatus main body 1 , an exhaust path is formed from the exhaust ports 227 and 228 to the duct exhaust port 244 via the inner duct 233 . When the upper unit 220 is opened with respect to the apparatus main body 1, the user interface 130 is exposed and accessible. Note that the lower duct 241 is configured as a second duct fixed to the apparatus main body 1 .

The air warmed by the fixing device 50 is exhausted from the exhaust ports 227 and 228 by the fans 91 and 92 and supplied to the inner duct 233 of the upper duct 224 from the air supply ports 230 and 231 . Air is then carried from the inner duct 233 to the outer duct 226 and from the outer duct 226 to the lower duct 241 . When the upper unit 220 of the duct unit 200 is closed with respect to the apparatus main body 1, the inner duct 233 prevents the HDD 121 from being exposed to air currents. This prevents the hot air discharged from exhaust port 228 from directly contacting HDD 121 .

Here, a sealing member 231a is fixed to the air supply port 231 with a double-sided tape in order to seal the gap between the air supply port 231 and the exhaust port 228. As shown in FIG. Since the size of this gap varies due to variations in the molding of individual components, mounting looseness, etc., it is preferable that the sealing member 231a compresses an elastic member that is thicker than the gap. In this embodiment, Opsealer JKX-1105 (manufactured by Sanwa Kako Co., Ltd.) is used as the sealing member 231a.

A sealing member 226 a is fixed to the outer duct 226 with double-sided tape in order to seal the gap between the cover member 225 and the fixing portion. As with the sealing member 231a, the sealing member 226a preferably has a structure in which an elastic member is compressed. In this embodiment, CALMFLEX F-2 (manufactured by INOAC Corporation) is used as the sealing member 226a.

A sealing member 241 a is fixed to the lower duct 241 with double-sided tape in order to seal the gap at the joint with the outer duct 226 . In this embodiment, Opsealer JKX-1105 (manufactured by Sanwa Kako Co., Ltd.) is used as the sealing member 241a. In order to suppress wear of the sealing member 241a due to opening and closing of the upper unit 220, PF-050H (manufactured by DIC Corporation) is used on the surface.

In order to suppress wear of the sealing member 241a when opening and closing the upper unit 220, the sealing member 241a is compressed in a direction perpendicular to the rotation axis direction of the upper unit 220 (horizontal direction in this embodiment). is desirable. However, if the connecting portion 250 with the lower duct 241 is formed according to the outer shape of the outer duct 226, the outer duct 226 and the lower duct 241 interfere when the upper unit 220 is opened and closed.

Therefore, as shown in FIG. 12, the connecting portion 250 of the lower duct 241 with the outer duct 226 is formed so that the region F along the outer shape of the outer duct 226 and the end portion 225a of the cover member 225 when the upper unit 220 rotates. and a region G along the trajectory through which it passes. Thereby, when the upper unit 220 is opened and closed, the outer duct 226 and the lower duct 241 do not interfere. Moreover, when the upper unit 220 is closed, the sealing member 241a can be compressed in a direction perpendicular to the axial direction of the shaft portions 221a and 221b.

Thus, in this embodiment, the upper unit 220 can be opened and closed with respect to the apparatus main body 1, and the sealing member 241a is provided between the apparatus main body 1 and the upper unit 220. FIG. Accordingly, a configuration in which the user interface 130 is provided near the position where the fixing device 50 is provided, which is on the side opposite to the side on which the sheet processing apparatus is mounted in the horizontal direction of the apparatus main body 1, is considered. Even with such a configuration, it is possible to suppress a decrease in the exhaust efficiency of the duct unit 200 without deteriorating the operability for the user.

FIG. 13 is a perspective view of the lower unit 240 with the fan holder 280 of the lower unit 240 removed. FIG. 14 is a perspective view of lower unit 240 with lower duct 241 and filter 260 of lower unit 240 removed. 14 shows a state in which the upper duct 224 is also removed.

As shown in FIGS. 13 and 14, the lower duct 241 is open on the upper duct 224 side, and this open portion and the outer duct 226 are connected. The lower duct 241 is screwed to fixing portions 280 a , 111 a , and 112 a provided on the upper cover 111 , the lower cover 112 , and the fan holder 280 . An upper cover 111 and a lower cover 112, which are plate-shaped members, are exteriors of the apparatus main body 1, and the lower unit 240 forms an air flow path with the lower duct 241, the upper cover 111, and the lower cover 112. FIG.

The upper cover 111 is provided with a sealing member 111b for sealing the gap between the upper cover 111 and the lower duct 241. As shown in FIG. In this embodiment, Opsealer JKX-1105 (manufactured by Sanwa Kako Co., Ltd.) is used as the sealing member 111b, and the sealing member 111b is attached to the rib 111d provided on the upper cover 111. FIG.

Also, in the lower unit 240 , the fan 102 and the filter 260 are provided inside the lower duct 241 . A duct exhaust port 244 is provided in the lower part of the lower duct 241 . The duct exhaust port 244 is an exhaust port provided at the downstream end of the lower duct 241 in the direction in which the air flows.

The filter 260 has a structure in which a filter medium 262 is fixed to a frame 261 made of resin. The filter material 262 is provided in a pleated shape within the frame 261, thereby increasing the surface area and improving the dust collection efficiency. In addition, strength is ensured by dividing the filter medium 262 into two and holding them with the frame 261 . In this embodiment, FM-9406WP (manufactured by Japan Vilene Co., Ltd.) is used as the filter medium 262 .

The vertical position of the filter 260 is regulated by the four positioning portions 243 , and the filter 260 is held by being sandwiched between the inner side of the lower duct 241 and the upper cover 111 . A sealing member 260 a is provided around the entire periphery of the frame 261 of the filter 260 to seal gaps with respect to the lower duct 241 , the upper cover 111 and the lower cover 112 . In this embodiment, CALMFLEX F-2 (manufactured by INOAC CORPORATION) is used as the sealing member 260a.

The fan 102 is held by a fan holder 280, and the fan holder 280 is fixed to the lower cover 112 with screws. The fan 102 is provided downstream of the airflow discharged from the duct outlet 244 relative to the filter 260 . Fan 102 generates an airflow for exhausting from duct outlet 244 of lower duct 241 .

Here, if the filter 260 and the fan 102 are too close to each other, the airflow generated by the fan 102 may pass through only a portion of the filter 260, reducing dust collection efficiency. Therefore, in this embodiment, a distance of about 40 mm is secured between the filter 260 and the fan 102 to maintain the dust collection efficiency. That is, the distance on the exhaust path between filter 260 and fan 102 is preferably 40 mm or more.

Further, the fan holder 280 is provided with a sealing member 280c to seal the gap between the fan holder 280 and the lower cover 112 . Further, a sealing member 280d is provided to seal the gap with the lower duct 241. As shown in FIG. In this embodiment, Opsealer JKX-1105 (manufactured by Sanwa Kako Co., Ltd.) is used as the sealing members 280c and 280d.

A bundle of wires 283 (electrical wires) for electrically connecting the fan 102 and a substrate (not shown) provided inside the image forming apparatus H is held by the fan holder 280 . The bundled wire 283 electrically connects the fan 102 and a board (not shown) provided inside the apparatus main body 1 (inside the upper cover 111 and the lower cover 112) via the relay connector 284. FIG.

15 is a cross-sectional view of the lower unit 240 taken along the KK cross section shown in FIG. 14. FIG. Note that FIG. 15 is a cross-sectional view showing a state in which the lower duct 241 and the filter 260 are attached. As shown in FIG. 15, between the upper cover 111 and the lower cover 112 as the exterior of the apparatus main body 1 facing the lower duct 241, there is an opening for passing the wire bundle 283 from the inside of the apparatus main body 1 of H. 285 is formed.

Further, the fan holder 280 is arranged to face the opening 285 with a gap therebetween, and is perpendicular to the rotation axis direction of the fan 102 (the direction of the line D shown in FIG. 15) (the front-rear direction of the image forming apparatus H). A cover portion 280b is provided to cover the opening 285 when viewed from above. The cover portion 280b extends obliquely in a direction counter to the flow of air flowing through the lower duct 241 . In other words, the tip of the cover portion 280b is located farther from the opening 285 than the base end thereof in the direction perpendicular to the rotation axis direction of the fan 102 . Also, the cover portion 280b is inclined such that the distal end thereof is farther from the upper cover 111 than the base end thereof.

By providing the cover portion 280b in this way, when the air flows through the duct unit 200, a swirling airflow E can be generated in the vicinity of the opening portion 285. As shown in FIG. This airflow E can prevent the air inside the device main body 1 (inner side of the device main body 1 than the upper cover 111 and the lower cover 112 ) from flowing into the lower duct 241 through the opening 285 . Therefore, it is possible to prevent adverse effects such as scattering of toner caused by unintended air flow in the apparatus main body, and to improve the exhaust efficiency of the lower duct 241 .

Further, in the present embodiment, the angle θ between the rotation axis direction of the fan 102 and the direction in which the cover portion 280b extends along the air flow path (the inclination angle of the cover portion 280b) is 10°. By setting the angle θ to 10° or more and 45° or less, the swirling airflow E is likely to be generated, and the above effects can be improved.

Further, in the upper cover 111 forming part of the lower duct 241, the lower end portion 111c on the side closer to the lower cover 112 (opening 285) is bent inwardly of the lower duct. That is, the lower end portion 111c of the upper cover 111 is inclined in a direction away from the lower cover 112 (outside of the apparatus main body 1). With such a configuration, the opening width of the opening 285 can be maintained, so that it becomes easy to secure a space for passing the bundle of wires of the fan 102 and other wiring. Further, even with the configuration in which the opening 285 for wiring the bundle 283 is provided, it is possible to prevent the air inside the apparatus main body 1 from flowing into the duct unit 200 through the opening 285 .

<Regarding the temperature distribution and air flow rate of the duct unit>
Next, the temperature distribution and air flow rate of the duct unit 200 will be described.

First, the temperature distribution of the duct unit 200 will be explained. FIG. 16 is a graph showing the temperature distribution inside the duct of the duct unit 200. As shown in FIG. As shown in FIG. 16, the duct unit 200 is provided outside the image forming apparatus H and exposed to the outside air.

Therefore, while the internal temperature near the inlet of the upper duct 224 is as high as 76°C, the internal temperature near the inlet 241x of the lower duct 241 and upstream of the filter 260 in the direction of air flow drops to 47°C. . That is, when the duct unit 200 is exposed to the outside air, the filter 260 detects the temperature difference between the first temperature of the air at the duct entrance and the second temperature of the air passing through the filter 260 (inside the filter). is at least 20° C. (predetermined temperature difference).

Here, the inlet of the upper duct 224 is the air supply port 230 and the air supply port 231 and is the upstream end side of the upper duct 224 in the direction of air flow in the duct unit 200 . The inlet 241x of the lower duct 241 is the upstream end side of the lower duct 241 in the direction of air flow in the duct unit 200, and is the end side opposite to the duct outlet 244 across the filter 260. It's about.

By configuring the duct unit 200 to be exposed to the outside air in this way and lowering the temperature of the air in the duct before the air reaches the filter 260 , dust aggregation is sufficiently advanced near the filter 260 . Therefore, the aggregation facilitates collection by the filter 260, so that the dust collection efficiency by the filter 260 can be improved.

Also, the air temperature drops to 41° C. near the duct outlet 244 . Therefore, it is possible to prevent the air discharged from the duct exhaust port 244 from becoming hot, and to prevent the user from feeling uncomfortable.

Next, the flow rate of air supplied to and exhausted from the upper duct 224 and the lower duct 241 will be described. FIG. 17 shows the flow rate A of air supplied from the air supply port 230 of the upper duct 224, the flow rate B of air taken in from the air supply port 231, the flow rate C of air exhausted from the duct exhaust port 244, 5 is a graph showing the relationship with the internal temperature of the image forming apparatus H. FIG.

Here, the flow rate A of air sucked from the air supply port 230 of the upper duct 224 is substantially equal to the flow rate of air discharged from the exhaust port 227 of the apparatus body 1 by the fan 91 . Also, the flow rate B of air supplied from the air supply port 231 is substantially equal to the flow rate of air discharged from the exhaust port 228 of the apparatus main body 1 by the fan 92 . Also, the flow rate C of air discharged from the duct outlet 244 is substantially equal to the flow rate of air discharged to the outside of the duct unit 200 by the fan 102 .

As shown in FIG. 17, when the flow rate relationship is C<A+B, the air warmed by the fixing device 50 cannot be exhausted sufficiently, and heat accumulates in the upper duct 224 and the lower duct 241, causing the image forming apparatus H to operate. Heat up. In this case, problems such as toner sticking may occur.

Therefore, the flow rate of the air supplied from the air supply ports 230 and 231 per unit time is made equal to or less than the flow rate of the air exhausted from the duct exhaust port 244 per unit time. That is, let the relationship among the flow rates A, B, and C be C≧A+B. As a result, the air heated by the fixing device 50 can be sufficiently exhausted, and the temperature rise of the image forming apparatus H can be suppressed. In this embodiment, the fan 102 is configured to increase the number of rotations of the fans 91 and 92 or to increase the size of the fan 102 itself to satisfy the above-described flow rate relationship.

<Placement of duct unit>
Next, the arrangement of the duct unit 200 will be explained.

FIG. 18 is a layout diagram of the duct unit 200 and the electric system unit when the image forming apparatus H is viewed from the rear side. As shown in FIG. 18, a controller board 120 having an electronic circuit for performing arithmetic processing for image output of received image data is arranged on the rear side of the apparatus body 1 of the image forming apparatus H. FIG. A power board 123 for supplying power to the apparatus main body, an engine control board 124, an HDD 121, and the like are also arranged.

Although not shown in FIG. 18, the upper cover 111 and the lower cover 112 are provided outside the image forming apparatus H as exterior covers so as to cover the controller board 120, the power supply board 123, the engine control board 124, and the like. ing. That is, the controller board 120 , the power supply board 123 and the engine control board 124 are provided inside the upper cover 111 and the lower cover 112 .

These electrical units, especially electronic components such as the CPU mounted on the power supply board 123 and the controller board 120, are sensitive to heat and require cooling. Therefore, fans 97 and 98 are provided near the controller board 120 and the power supply board 123 to cool the electronic components mounted on these boards. Also, the fans 97 and 98 and the louvers 113 and 114 which are exterior coverings of the fans 97 and 98 are positioned to overlap the controller board 120 and the power supply board 123 when viewed from the rear side of the apparatus main body 1 of the image forming apparatus H. is provided in Further, a louver 115 is provided as an exterior of the image forming apparatus H at a position overlapping the engine control board 124 when viewed from the rear side of the apparatus main body 1 of the image forming apparatus H. As shown in FIG.

As described above, the air passing through the duct unit 200 is relatively high temperature air warmed by the fixing device 50 . Therefore, when the duct unit 200 is positioned so as to overlap with the electric system unit when the image forming apparatus H is viewed from the back side, the temperature of the electric system unit tends to rise due to the high-temperature air passing through the duct unit 200. Become.

Therefore, the duct unit 200, the controller board 120, the HDD 121, the power supply board 123, and the engine control board 124 are arranged so as not to overlap when viewed from the rear side of the apparatus main body 1 of the image forming apparatus H. FIG. That is, when the image forming apparatus H is viewed from the rear side, the upper duct 224 is arranged beside the controller board 120, and the lower duct 241 is arranged so that a part of the lower duct 241 is positioned below the controller board 120 in the vertical direction. are placed. As a result, the air inside the image forming apparatus H can be exhausted to the outside through the duct unit 200 without hindering the cooling efficiency of the electrical system unit.

With such a configuration, it is possible to suppress the temperature rise of the electric system unit that requires cooling. Further, since the duct unit 200 does not block the louvers 113, 114, 115, it is possible to prevent the cooling of the electric system unit from being hindered.

In this embodiment, the duct unit 200 is arranged to avoid the controller board 120, the HDD 121, the power supply board 123, and the engine control board 124, but the arrangement is not limited to this. Any other configuration may be used as long as the duct unit 200 is arranged at a position avoiding at least the electrical unit that is vulnerable to heat. Further, the duct unit 200 may be provided at a position overlapping the apparatus main body 1 in the front-rear direction with respect to a drive system board such as a motor driver on which electronic components vulnerable to heat are not mounted.

Further, according to the present invention, it is possible to achieve both noise reduction and low power consumption while collecting generated dust.

DESCRIPTION OF SYMBOLS 1... Apparatus main body 91... Fan 92... Fan 200... Duct unit 227... Exhaust port (first exhaust port)
228 ... exhaust port (first exhaust port)
230... Air supply port (duct entrance)
231 ... Air supply port (duct entrance)
244... Duct exhaust port (second exhaust port)
260 Filter H Image forming apparatus

Claims (4)

In an image forming apparatus that forms an image by heating a toner image transferred onto a recording material in a fixing section and fixing the toner image onto the recording material,
a first exhaust port for exhausting the air warmed by the fixing unit to the outside of the apparatus main body;
a duct attached to the exterior of the device main body and forming a flow path for discharging the air exhausted from the first exhaust port to the outside of the device main body;
a second exhaust port provided at a downstream end of the duct in the direction in which the air flows, for exhausting the air exhausted from the first exhaust port to the outside;
a filter provided on the exhaust path between the first exhaust port and the second exhaust port inside the duct for collecting dust;
a first fan for generating an airflow for exhausting air from the first exhaust port and taking the air into the duct ;
a second fan provided inside the duct for generating an airflow for exhausting the air taken into the duct through the first exhaust port through the second exhaust port;
has
When the duct is exposed to the outside air, the filter has a first temperature of the air at the duct inlet and a second temperature lower than the first temperature of the air passing through the filter. provided at a position where the temperature difference between the
The duct is
Consists of a first duct and a second duct connected to the first duct,
the centerline of the first duct and the centerline of the second fan do not overlap;
An image forming apparatus characterized by: 2. The image forming apparatus according to claim 1, wherein a temperature difference between said first temperature and said second temperature is 20[deg.] C. or more. 3. The image forming apparatus according to claim 1, wherein the duct is attached to the exterior on the rear side of the apparatus main body. 4. The image forming apparatus according to claim 1, wherein the distance on the exhaust path between the filter and the second fan is 40 mm or more.

Images