阅读说明：本技术 流路结构以及图像形成装置 (Flow path structure and image forming apparatus ) 是由 川谷哲也 笠井康吉 石井一成 野村由佳 于 2019-03-07 设计创作，主要内容包括：本发明得到一种比空气沿着管道壁面流动的结构降低超微粒子排出量的流路结构以及图像形成装置。流路结构包括：管道,具备输送空气的流路,通过送风部件来抽吸对记录介质上的墨粉像进行定影的定影装置周围的空气；以及导电性的碰撞面,设在所述管道的内部,且沿与所述管道内部的空气输送方向交叉的方向而配置。(The invention provides flow path structures and image forming apparatuses which reduce the discharge amount of ultrafine particles compared with a structure in which air flows along the wall surface of a duct, the flow path structures include a duct having a flow path for transporting air and sucking air around a fixing device for fixing a toner image on a recording medium by a blowing member, and a conductive collision surface provided inside the duct and arranged in a direction intersecting the air transport direction inside the duct.)

1, A flow path structure comprising:

a duct having a flow path for conveying air, and sucking air around a fixing device for fixing a toner image on a recording medium by an air blowing member; and

and an electrically conductive collision surface provided inside the duct and arranged in a direction intersecting with an air transport direction inside the duct.

2. The flow path structure according to claim 1,

the duct is provided with a narrowing portion that narrows the flow path,

the collision surface is provided at a position where the air narrowed by the narrowing portion collides.

3. The flow path structure according to claim 2,

the constriction is configured to function as the collision surface and constrict the flow path.

4. The flow path structure according to claim 2,

the constriction is configured to function as an inner wall of the duct and constrict the flow path.

5. The flow path structure according to claim 1 or 2,

the air flow velocity is increased toward the downstream side of the flow path in the air conveying direction, and the air is caused to collide with the collision surface.

6. The flow path structure according to claim 5,

the collision surface is disposed on the downstream side in the air conveying direction of a constriction that constricts the flow path, and a plurality of constrictions and the collision surface are provided.

7. The flow path structure according to claim 6,

the constriction portion on the downstream side in the air conveying direction narrows the flow path more than the constriction portion on the upstream side in the air conveying direction.

8. The flow path structure according to claim 5,

the collision surfaces are provided in plural, and the interval between the collision surfaces becomes narrower toward the downstream side in the air conveying direction.

9. The flow path structure according to claim 5,

the collision surface is provided in plural, and the angle of the downstream side of the collision surface with respect to the inner wall surface of the duct becomes larger toward the downstream side in the air conveying direction.

10. The flow path structure according to claim 1,

the collision surface is provided in plurality, and the angle of the downstream side of the collision surface relative to the inner wall surface of the pipeline is smaller than 90 degrees.

11. The flow path structure according to of any one of claims 1 to 10, wherein,

the inner wall surface of the duct includes a conductive member.

12. The flow path structure according to of any one of claims 1 to 11, wherein,

the conduit comprises an inlet, an outlet, and a wall connecting the inlet and the outlet,

the inlet is provided at a position upstream of the fixing device in a transport direction including the recording medium.

An image forming apparatus of kinds, comprising:

an image forming section that forms a toner image and transfers the toner image to the recording medium;

a fixing device for fixing the toner image transferred to the recording medium; and

the flow path structure of any of claims 1-12, into which air flows around the fixing device.

Technical Field

The present invention relates to kinds of flow path structures and an image forming apparatus.

Background

Patent document 1 listed below discloses types of image forming apparatuses in which a filter (filter) is provided in an exhaust duct (duct), and the flow of air is switched so as to pass through the filter only when a large amount of ultrafine particles are generated in order to prolong the life of the filter.

Patent document 2 discloses types of image forming apparatuses in which is discharged together with a paper discharge while a fixing off-gas is swirled inside the apparatus.

Patent document 3 listed below discloses types of image forming apparatuses in which a partition plate and a heating device are provided in a duct to generate a vortex flow, thereby improving the collection efficiency of a filter and prolonging the life of the filter.

[ Prior art documents ]

[ patent document ]

Patent document 1: japanese patent laid-open publication No. 2016-085407

Patent document 2: japanese patent laid-open publication No. 2017-003770

Patent document 3: japanese patent laid-open No. 2015-214164

Disclosure of Invention

[ problems to be solved by the invention ]

The invention aims to obtain flow path structures and image forming devices which reduce the discharge amount of Ultra Fine Particle (UFP) compared with the structure that air flows along the wall surface of a pipeline.

[ means for solving problems ]

The flow path structure of the invention described in claim 1 includes: a duct having a flow path for conveying air, and sucking air around a fixing device for fixing a toner image on a recording medium by an air blowing member; and an electrically conductive collision surface provided inside the duct and arranged in a direction intersecting with an air transport direction inside the duct.

The invention described in claim 2 is the flow path structure described in claim 1, wherein the duct includes a narrowing portion that narrows the flow path, and the collision surface is provided at a position where air narrowed by the narrowing portion collides.

The invention described in claim 3 is the flow path structure described in claim 2, wherein the constriction portion is configured to constrict the flow path by the collision surface.

The invention described in claim 4 is the flow path structure described in claim 2, wherein the narrowing portion is configured to narrow the flow path by an inner wall of the duct.

The invention described in claim 5 is the flow path structure described in claim 1 or claim 2, wherein the flow path structure is configured such that the air collides with the collision surface by increasing the flow velocity of the air toward the downstream side in the air conveyance direction of the flow path.

The invention described in claim 6 is the flow path structure described in claim 5, wherein the collision surface is disposed on an air conveyance direction downstream side of a constriction that constricts the flow path, and a plurality of constrictions and collision surfaces are provided.

The invention described in claim 7 is the flow path structure described in claim 6, wherein the narrowing portion on the downstream side in the air transporting direction narrows the flow path more than the narrowing portion on the upstream side in the air transporting direction.

The invention described in claim 8 is the flow path structure described in claim 5, wherein a plurality of the collision surfaces are provided, and the interval between the collision surfaces becomes narrower toward the downstream side in the air conveying direction.

The invention described in claim 9 is the flow path structure described in claim 5, wherein a plurality of the collision surfaces are provided, and an angle of a downstream side of the collision surface with respect to the inner wall surface of the duct becomes larger toward a downstream side in an air conveying direction.

The invention described in claim 10 is the flow path structure described in claim 1, wherein a plurality of collision surfaces are provided, and an angle of a downstream side of the collision surfaces with respect to the inner wall surface of the duct is smaller than 90 degrees.

The invention described in claim 11 is the flow path structure according to any of claims 1 to 10, wherein an inner wall surface of the pipe includes an electrically conductive member.

The invention described in claim 12 is the flow path structure according to any of claims 1 to 11, wherein the duct includes an inlet, an outlet, and a wall portion connecting the inlet and the outlet, and the inlet is provided at a position on an upstream side of the fixing device in a transport direction including the recording medium.

The image forming apparatus of the invention described in claim 13 includes an image forming section that forms a toner image and transfers the toner image to the recording medium, a fixing device that fixes the toner image transferred to the recording medium, and the flow path structure described in any of claims 1 to 12, into which air around the fixing device flows.

[ Effect of the invention ]

According to the invention described in claim 1, the amount of ultrafine particles discharged is reduced as compared with a structure in which air flows along the wall surface of the duct.

According to the invention described in claim 2, the amount of ultrafine particles discharged is reduced as compared with a structure in which the flow path is not narrowed.

According to the invention described in claim 3, the structure is simpler than a structure having a dedicated narrowing member.

According to the invention described in claim 4, the structure is simpler than a structure having a dedicated narrowing member.

According to the invention described in claim 5, the amount of ultrafine particles discharged is reduced as compared with a configuration in which the flow velocity in the air transport direction of the flow path is equal.

According to the invention described in claim 6, the amount of ultrafine particles discharged is reduced as compared with the structure in which constrictions and collision surfaces are provided.

According to the invention described in claim 7, the amount of ultrafine particles discharged is reduced as compared with a configuration in which the size of the constriction is equal along the air transportation direction.

According to the invention described in claim 8, the amount of ultrafine particles discharged is reduced as compared with a configuration in which the intervals between the collision surfaces are equal as they go downstream in the air conveyance direction.

According to the invention described in claim 9, the amount of ultrafine particles discharged is reduced as compared with a configuration in which the angle of the downstream side of the collision surface with respect to the inner wall surface of the duct is equal.

According to the invention described in claim 10, the amount of ultrafine particles discharged is reduced as compared with the case where the angle of the downstream side of the collision surface with respect to the inner wall surface of the pipe is 90 degrees or more.

According to the invention described in claim 11, the amount of ultrafine particles discharged is reduced as compared with a structure in which the inner wall surface of the pipe is an insulator.

According to the invention described in claim 12, the ultrafine particles easily flow into the duct, as compared with a configuration in which a duct entrance is provided on the downstream side of the fixing device in the transport direction of the recording medium.

According to the invention of claim 13, the discharge amount of ultrafine particles from the apparatus main body is reduced as compared with a configuration in which air flows along the wall surface of the duct.

Drawings

Fig. 1 is a configuration diagram showing an image forming apparatus to which a flow path configuration according to embodiment 1 is applied.

Fig. 2 is a perspective view showing a duct used in the flow path structure of embodiment 1 and a fixing device in which the duct is disposed.

Fig. 3 is a side sectional view showing a state in which a duct used in the flow path structure of embodiment 1 is disposed on the inlet side of the fixing device in the sheet conveying direction.

Fig. 4 is a schematic cross-sectional view showing a duct used in the flow path structure of embodiment 1 and a fixing device in which the duct is disposed.

Fig. 5 is a sectional view showing a pipe used in the flow path structure of embodiment 2.

Fig. 6 is a sectional view showing a pipe used in the flow path structure of embodiment 3.

Fig. 7 is a sectional view showing a pipe used in the flow path structure of embodiment 4.

Fig. 8 is a sectional view showing a pipe used in the flow path structure of embodiment 5.

Fig. 9 is a schematic diagram showing the flow rate of air flowing in the duct used in the flow path structure of embodiment 5.

Fig. 10 is a sectional view showing a pipe used in the flow path structure of embodiment 6.

Fig. 11 is a sectional view showing a pipe used in the flow path structure of embodiment 7.

Fig. 12 is a sectional view showing a pipe used in the flow path structure of embodiment 8.

Fig. 13 is a sectional view showing a pipe used in the flow path structure of embodiment 9.

Fig. 14 is a sectional view showing a pipe used in the flow path structure of embodiment 10.

Fig. 15 is a sectional view showing a pipe used in the flow path structure of embodiment 11.

Fig. 16(a) is a sectional view showing a case where the angle of the upstream side of the metal plate in the duct is 135 °, fig. 16(B) is a sectional view showing a case where the angle of the upstream side of the metal plate in the duct is 90 °, and fig. 16(C) is a sectional view showing a case where the angle of the upstream side of the metal plate in the duct is 45 °.

FIG. 17 is a graph showing the relationship between the angle of the metal plate in the duct and the capture rate of ultrafine particles.

Fig. 18(a) is a side sectional view showing an example in which the duct used in the flow path structure is disposed on the exit side of the fixing device in the sheet conveying direction, fig. 18(B) is a side sectional view showing an example in which the duct used in the flow path structure is disposed near the center portion of the fixing device in the sheet conveying direction, and fig. 18(C) is a side sectional view showing an example in which the duct used in the flow path structure is disposed so as to cover the entire fixing device in the sheet conveying direction.

Description of the symbols

10: image forming apparatus with a toner supply device

20: image forming apparatus with a toner cartridge

50: fixing device

100: flow path structure

102: pipeline

102A 1 st pipe section ( example wall section)

102B 2 nd pipe part ( example wall part)

102C 3 rd pipe part ( example wall part)

103: inlet port

104: flow path

106: air supply device

106C: an outlet

108: fan with cooling device

110 collision board ( cases of collision surface)

112: inner wall surface

120: flow path structure

122: narrowing part

130: flow path structure

132: narrowing part

134 collision board ( cases of collision surface)

140: flow path structure

150: flow path structure

152: narrowing part

154: narrowing part

160: flow path structure

162: narrowing part

164: narrowing part

166: narrowing part

170: flow path structure

172: narrowing part

174: narrowing part

176: narrowing part

180: flow path structure

182: pipeline

184: flow path

185A: inner wall

186: narrowing part

190: flow path structure

192 collision board ( case of collision surface)

194 collision board ( cases of collision surface)

196 collision board ( cases of collision surface)

200: flow path structure

210: flow path structure

212A: narrowing part

212B: narrowing part

212C: narrowing part

214A: narrowing part

214B: narrowing part

214C: narrowing part

220: flow path structure

222: narrowing part

224: narrowing part

230: flow path structure

232: narrowing part

234: narrowing part

240: flow path structure

242: narrowing part

244: narrowing part

260: flow path structure

262: pipeline

262A: inlet port

264: flow path structure

266: pipeline

266A: inlet port

268: flow path structure

270: pipeline

270A: inlet port

θ 1: angle of rotation

θ 2: angle of rotation

θ 3: angle of rotation

L1: spacer

L2: spacer

L3: spacer

P paper ( cases of recording medium)

Detailed Description

Hereinafter, embodiments of the present invention will be described based on the drawings. Note that a direction indicated by an arrow H appropriately shown in the drawings is referred to as an apparatus height direction (vertical direction), and a direction indicated by an arrow W is referred to as an apparatus width direction (horizontal direction). The direction indicated by the arrow D, that is, the direction orthogonal to the device height direction and the device width direction is the device depth direction (horizontal direction).

[ 1 st embodiment ]

An example of an image forming apparatus according to embodiment 1 of the present invention will be described with reference to fig. 1 to 4, wherein yellow is represented as Y, magenta is represented as M, cyan is represented as C, and black is represented as K, and when it is necessary to distinguish the constituent parts and the toner images (images) for each color, a color symbol (Y, M, C, K) corresponding to each color is provided at the end of the symbol to describe the same, and when it is not necessary to distinguish the constituent parts and the toner images for each color and the same is collectively referred to, the description will be omitted with the color symbol at the end of the symbol.

(entire Structure of image Forming apparatus)

Fig. 1 shows examples of the configuration of the image forming apparatus according to the present embodiment, as shown in fig. 1, an image forming apparatus 10 includes a storage unit 14 that stores therein examples of sheets P as recording media, and a transport device 16 that transports the sheets P stored in the storage unit 14, and further, the image forming apparatus 10 includes an image forming unit 20 that forms an image on the sheet P transported from the storage unit 14 by the transport device 16, and a control unit 12 that controls each unit, and a document reading unit that reads a document is provided above an apparatus main body 10A of the image forming apparatus 10, although not shown.

In the storage portion 14, two storage members 26 are disposed so as to be extractable from the apparatus main body 10A of the image forming apparatus 10 toward the near side in the apparatus depth direction, and for example, two types of paper P are loaded on each of the storage members 26. Further, in each of the storage members 26, a delivery roller 30 is disposed, and the delivery roller 30 delivers the paper P loaded in the storage member 26 to a conveyance path 28 provided in the conveyance device 16.

The conveying device 16 includes a plurality of pairs of conveying rollers 31 for conveying the sheet P along a conveying path 28 for conveying the sheet P, and pairs of registration rollers 32 for aligning the conveying timing of the sheet P.

In the image forming portion 20, four image forming units 18Y, 18M, 18C, and 18K of yellow (Y), magenta (M), cyan (C), and black (K) are arranged. The image forming units 18 of the respective colors are detachable from the apparatus main body 10A. Further, in the image forming unit 18 of each color, a photosensitive drum 36 that rotates counterclockwise in fig. 1 and a charging member 38 that charges the surface of the photosensitive drum 36 are disposed. Further, the image forming unit 18 includes: an exposure device 39 for irradiating the charged photoconductive drum 36 with exposure light; and a developing device 40 that develops the electrostatic latent image formed by the irradiation of the exposure light with a developer to visualize the electrostatic latent image as a toner image. Further, in the image forming unit 18, a cleaning device 42 is disposed, and the cleaning device 42 scrapes off foreign substances adhering to the photosensitive drum 36 from the photosensitive drum 36.

Further, in the image forming section 20, an endless transfer belt 22 is disposed, and the transfer belt 22 is wound around an auxiliary roller 52 and a plurality of rollers 60 and 62 described later and rotated in the direction of an arrow a in the drawing, and further, in the image forming section 20, secondary transfer rollers 54Y, 54M, 54C, and 54K are disposed, and the secondary transfer rollers 54Y, 54M, 54C, and 54K are disposed inside the transfer belt 22 and transfer toner images formed by the image forming units 18 of the respective colors to the surface 22a of the transfer belt 22. here, the transfer belt 22 is an example of an image holding body . further, in the image forming section 20, a cleaning device 34 is disposed, and the cleaning device 34 scrapes foreign matters such as residual toner adhering to the transfer belt 22 from the transfer belt 22 by a blade (blade) 35.

Further, in the image forming section 20, a secondary transfer section 56 of example as a transfer section is disposed, the secondary transfer section 56 transfers the toner image transferred to the surface 22A of the transfer belt 22 to the paper P, and in the secondary transfer section 56, a secondary transfer roller 58 disposed on the surface side of the transfer belt 22 and an auxiliary roller 52 that winds the transfer belt 22 on the opposite side of the transfer belt 22 with respect to the secondary transfer roller 58 are disposed, the auxiliary roller 52 rotates following the rotating transfer belt 22, in the present embodiment, the secondary transfer roller 58 is grounded, the auxiliary roller 52 forms an opposing electrode of the secondary transfer roller 58, and the auxiliary roller 52 transfers the toner image to the paper P by applying a secondary transfer voltage.

Further, in the apparatus main body 10A, a fixing device 50 is disposed downstream of the secondary transfer section 56 in the conveying direction of the sheet P, and the fixing device 50 heats and pressurizes the sheet P to which the toner image is transferred to fix the toner image to the sheet P. In the fixing device 50, disposed are: a heating rotary body 51A that heats the toner image on the surface of the sheet P; and a pressing rotor 51B that presses the sheet P from the back side to the heating rotor 51A.

Further, in the conveyance device 16 of the apparatus main body 10A, pairs of discharge rollers 28A and 28B are provided on the downstream side of the fixing device 50 in the conveyance direction of the sheet P, and pairs of discharge rollers 28A and 28B discharge the sheet P to the discharge unit 11 provided on the upper portion of the apparatus main body 10A.

Further, in the conveying device 16, a reversing conveying unit 70 used when forming images on both sides of the sheet P is disposed on the side of the image forming unit 20, the reversing conveying unit 70 has a function of reversing the front and back of the sheet P without directly discharging the sheet P, on which the toner image is fixed on the surface of side, to the discharging unit 11 by the discharging rollers 28A and 28B, and forming the toner image on the back of the other side of the sheet P, and a reversing path 72 for conveying the sheet P in such a manner that the front and back of the sheet P are reversed from the discharging rollers 28A and 28B toward the registration roller 32, and a plurality of conveying roller pairs (not shown) for conveying the sheet P along the reversing path 72 are disposed in the reversing conveying unit 70.

(function of image Forming apparatus)

In the image forming apparatus 10, an image is formed in the following manner.

First, the charging member 38 of each color to which a voltage is applied negatively charges the surface of the photosensitive drum 36 of each color at -fold at a predetermined potential, and then, based on image data read by a document reading unit (not shown), the exposure device 39 irradiates the surface of the photosensitive drum 36 of each color charged with exposure light to form an electrostatic latent image, thereby forming an electrostatic latent image corresponding to the data on the surface of the photosensitive drum 36 of each color, and further, the developing device 40 of each color develops the electrostatic latent image to visualize it as a toner image, and the toner image formed on the surface of the photosensitive drum 36 of each color is sequentially transferred to the transfer belt 22 by the secondary transfer roller 54, and the transfer belt 22 holds the toner image on the surface 22A as described above.

Therefore, the paper P fed out from the storage member 26 to the conveyance path 28 by the feeding roller 30 is fed out to the transfer nip portion N where the transfer belt 22 and the secondary transfer roller 58 contact. In the transfer nip portion N, the paper P is conveyed between the transfer belt 22 and the secondary transfer roller 58, whereby the toner image of the surface 22A of the transfer belt 22 is transferred to the surface of the paper P.

Further, the toner image transferred to the surface of the paper P is fixed to the paper P by the fixing device 50. The sheet P with the toner image fixed thereon is discharged to the discharge portion 11 outside the apparatus main body 10A by the rotation of the discharge rollers 28A and 28B.

Further , when forming images on both sides of the paper P, the discharge rollers 28A and 28B are reversed with the rear end of the paper P sandwiched therebetween, thereby conveying the paper P to the reverse path 72, and the paper P is conveyed to the secondary transfer portion 56 at a predetermined timing by the rotation of the registration roller 32, thereby transferring the toner image from the transfer belt 22 to the back surface of the paper P, the toner image transferred to the back surface of the paper P is fixed to the paper P by the fixing device 50, and the paper P with the toner image fixed thereto is discharged to the discharge portion 11 outside the apparatus main body 10A by the rotation of the discharge rollers 28A and 28B, thereby forming images on both sides of the paper P.

(main part structure)

Next, the fixing device 50, which is a main part of the image forming apparatus 10, and the flow path structure 100 of embodiment 1 will be described.

< fixing device 50 >

As shown in fig. 2 and 3, the fixing device 50 includes a heating rotor 51A disposed along the device depth direction, and a pressing rotor 51B disposed in contact with the heating rotor 51A and along the device depth direction, and further, the fixing device 50 includes a frame 80 covering a range of the heating rotor 51A except for an side in contact with the pressing rotor 51B, and a frame 82 covering a range of the pressing rotor 51B except for a side in contact with the heating rotor 51A, and the structure of the fixing device 50 is illustrated in a schematic cross-sectional view in fig. 3 for the sake of easy understanding of the structure of the fixing device 50.

The frame 80 is disposed so as to surround: the upstream side (lower side in the present embodiment) of heating rotor 51A in the conveyance direction of sheet P (direction of arrow P1 shown in fig. 3), the opposite side (rear side of heating rotor 51A) of the contact portion of heating rotor 51A with pressing rotor 51B, and the downstream side (upper side in the present embodiment) of heating rotor 51A in the conveyance direction of sheet P. The frame 82 is disposed so as to surround: the upstream side (middle lower side in the present embodiment) of pressing rotor 51B in the conveyance direction of sheet P, the opposite side (back side of pressing rotor 51B) of the position of pressing rotor 51B in contact with heating rotor 51A, and the downstream side (upper side in the present embodiment) of pressing rotor 51B in the conveyance direction of sheet P.

< flow path Structure 100 >

The flow path structure 100 includes a duct 102 for sucking air around the fixing device 50 by a fan (fan)108 (see fig. 4) described later. In the present embodiment, duct 102 is connected to lower portion 80A of casing 80 on the upstream side of heating rotor 51A in the conveyance direction of sheet P. Inside the duct 102, a flow path 104 (see fig. 4) for transporting air is provided.

As shown in fig. 2, the duct 102 includes a 1 st duct portion 102A connected to the lower portion 80A of the housing 80 and arranged to face the depth direction inner side of the apparatus, and a 2 nd duct portion 102B arranged from the downstream side end of the 1 st duct portion 102A to the upper side of the apparatus in the vertical direction, an inlet 103 (see fig. 3) for introducing air into the 1 st duct portion 102A is connected to the lower portion 80A of the housing 80, the duct 102 includes a 3 rd duct portion 102C arranged from the upper end of the 2 nd duct portion 102A to the depth direction inner side of the apparatus, and an air blowing device 106 of example as an air blowing means is provided at the downstream side end of the 3 rd duct portion 102C.

The blower 106 includes a substantially rectangular tubular body 106A, a fan 108 (see fig. 4) is disposed inside the tubular body 106A, the axial direction of the rotation shaft of the fan 108 is disposed along the longitudinal direction of the 3 rd duct portion 102C, and air is thereby conveyed through the flow path 104 in the duct 102 by the rotation of the fan 108, an outlet 106C (see fig. 4) for discharging air inside the duct 102 is provided at an end portion of the tubular body 106A, the outlet 106C is provided at an outer wall portion of the image forming apparatus 10, the 1 st duct portion 102A, the 2 nd duct portion 102B, the 3 rd duct portion 102C, and the tubular body 106A are examples of wall portions connecting the inlet 103 and the outlet 106C of the duct 102, the inlet 103 of the duct 102 is provided at a position on the upstream side in the housing 80 of the fixing device 50 (i.e., the inlet side of the fixing device 50) in the conveying direction (the arrow P1 direction) including the sheet P (see fig. 2 and 3).

As shown in fig. 4, a conductive collision plate 110 arranged in a direction intersecting the air transport direction (the direction of arrow B) inside the duct 102 is provided inside the duct 102, and a plurality of (three in the present embodiment) collision plates 110 are provided inside the duct 102, in the present embodiment, the plurality of collision plates 110 are equal in size, here, the surface of the collision plate 110 facing the upstream side is of the collision surface, and "conductivity" means a state in which the surface potential of the collision plate 110 is finally made less than 10 by lowering the potential of the collision plate 110 to ground (earth), and a surface potentiometer model344 manufactured by trekkan corporation is used as the surface potentiometer, and the ground may be connected to the collision plate 110 or not connected thereto, and in fig. 4, for the sake of convenience in understanding the structure of the flow path structure 100, the plate thickness and the frame body 80 are omitted, and the cross section of the duct 102 is straightly developed.

The plurality of collision plates 110 are provided in the center portion of the duct 102 in the width direction, and a space is provided between both sides of the collision plates 110 in the width direction and the inner wall surface 112 of the duct 102. Thus, air will flow between the impingement plate 110 and the inner wall surface 112 of the duct 102. In the present embodiment, the collision plate 110 is made of metal such as aluminum, copper, brass, and Stainless Steel (SUS), for example. Further, instead of metal, conductive plastic (plastic) or the like may be used as a material of the collision plate 110. As the conductive plastic, a plastic or the like in which carbon black (carbon black) or the like is added to a resin to improve conductivity is used. Further, only the surface on the upstream side of the collision plate 110 in the air conveyance direction inside the duct 102 may be made conductive.

In the flow path structure 100, air is sent in the direction of arrow B in the flow path 104 in the duct 102 by the rotation of the fan 108, the collision plate 110 is disposed in the center of the substantially rectangular flow path 104 in the direction intersecting the air sending direction (the direction of arrow B, i.e., the longitudinal direction of the duct 102 when viewed from above), in the present embodiment, the collision plate 110 is disposed in the direction orthogonal to the air sending direction (the direction of arrow B), and the collision plate 110 is supported by the portion of the inner wall surface 112 of the duct 102.

, the inner wall surface 112 of the pipe 102 includes a conductive member, and in the present embodiment, a metal foil such as aluminum foil (aluminum foil) is bonded to the inner wall surface 112 of the pipe 102.

(action and Effect)

Next, the operation and effect of the present embodiment will be described.

As shown in fig. 4, in the flow path structure 100, air around the fixing device 50 is sucked to the duct 102 side as indicated by an arrow a by rotation of the fan 108. The air introduced into the duct 102 from the inlet 103 (see fig. 3) of the duct 102 is sent in the direction of arrow B in the flow path 104 in the duct 102. And is discharged from the outlet 106C of the duct 102 to the outside of the image forming apparatus 10.

Here, a flow path structure (not shown) of the image forming apparatus of the comparative example will be described. In the flow path structure of the image forming apparatus according to the comparative example, a fan was provided on the downstream side of the duct flow path with a filter interposed therebetween. In recent years, due to the increasing awareness of the environment and safety, the restrictions on the emissions from the exterior of image forming apparatuses, particularly on Ultra Fine Particles (UFP) having a Particle size of 100nm or less, have become strict in the environmental standards (levels) of various countries. In the image forming apparatus of the comparative example, the air discharged to the outside of the image forming apparatus was cleaned by capturing the ultrafine particles with the filter provided in the duct.

However, in the flow path structure of the image forming apparatus of the comparative example, if the filter is provided, the cost increases, and the air from the image forming apparatus is hard to flow due to the influence of the pressure loss, so that the temperature in the image forming apparatus may increase. On the other hand, if the fan capacity is increased to secure the flow rate, noise and power consumption may increase.

In contrast, in flow path structure 100 of image forming apparatus 10 according to the present embodiment, a plurality of conductive collision plates 110 are provided inside duct 102. The plurality of conductive collision plates 110 are arranged in a direction intersecting the air conveyance direction (the direction of arrow B) inside the duct 102. Thereby, the air transported inside the duct 102 collides with the plurality of collision plates 110, and the ultrafine particles (UFPs) adhere to the plurality of collision plates 110. It has been confirmed through experiments that the conductive collision plate 110 is more likely to have ultrafine particles attached thereto than a non-conductive collision plate. Therefore, the amount of ultrafine particles (UFPs) contained in the air decreases on the downstream side of the plurality of collision plates 110 in the air conveyance direction of the duct 102.

In the flow path structure 100, the discharge amount of ultrafine particles (UFPs), that is, the discharge amount of the ultrafine particles (UFPs) discharged from the outlet 106C of the duct 102 to the outside of the image forming apparatus 10, is reduced as compared to a structure in which air flows along the wall surface of the duct.

Further, in image forming apparatus 10, since a system having a lower pressure loss than the filter can be constructed by reducing the ultrafine particles without using the filter, the influence on noise and power can be reduced without increasing the capacity of fan 108. Further, although the filter requires replacement cost due to the lifetime in addition to the initial cost, the image forming apparatus 10 does not require replacement cost due to the lifetime as compared with the case of using the filter, and therefore, an inexpensive system can be provided.

In the flow path structure 100, the inlet 103 of the duct 102 is provided at a position on the upstream side of the fixing device 50 in the conveyance direction including the sheet P. Therefore, in the image forming apparatus 10, the ultrafine particles are more likely to flow into the duct 102 than in a configuration in which a duct entrance is provided on the downstream side of the fixing device in the conveying direction of the sheet P.

In the flow path structure 100, the inner wall surface 112 of the duct 102 includes a conductive member. Therefore, in the flow path structure 100, the ultrafine particles are more likely to adhere to or aggregate on the inner wall surface 112 of the pipe 102 than in a structure in which the inner wall surface of the pipe is an insulator. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

[ 2 nd embodiment ]

Next, the flow path structure of embodiment 2 will be described with reference to fig. 5. The same components as those in embodiment 1 are denoted by the same reference numerals and their description is omitted.

As shown in fig. 5, the flow path structure 120 is provided with narrowing portions 122, 122 for narrowing the flow path 104 of the duct 102. Further, in the flow path structure 120, the collision plate 110 is provided at a position where the air narrowed by the narrowed portions 122, 122 collides.

The narrowed portions 122, 122 include pairs of conductive plate-like bodies, pairs of conductive plate-like bodies are supported at opposing positions on the inner wall surface 112 of the duct 102 and are disposed so as to protrude into the flow path 104, the narrowed portions 122, 122 are made of, for example, metal, and a space for passing air is set between pairs of the narrowed portions 122, and the angle of the downstream side of the narrowed portions 122, 122 with respect to the inner wall surface 112 (the angle of the downstream side of the flow path 104 in the air transport direction) is preferably 90 ° or less and 10 ° or more, more preferably 80 ° or less and 20 ° or more, and still more preferably 70 ° or less and 30 ° or more.

In , the distance between the narrowed portions 122, 122 in is smaller than the size of the collision plate 110, and the distance between the narrowed portions 122, 122 in is larger than the distance between the filter holes in the filter of the comparative example, therefore, the distance between the narrowed portions 122, 122 in is not so large as to cause clogging as in the filter of the comparative example, and thus not to affect the pressure loss.

The collision plate 110 is disposed so as to face a position downstream of the pair of the narrowed portions 122, 122 in the air conveyance direction (the direction of arrow B) and at a position where a gap pair of the narrowed portions 122, 122 is provided, and in the present embodiment, the flow path is narrowed by the narrowed portions 122, 122 by , so that the air collides with the collision plate 110 as the flow speed of the air increases toward the downstream side in the air conveyance direction.

The flow path structure 120 has the following effects in addition to the effects of the structure equivalent to the flow path structure 100 of embodiment 1. In the flow channel structure 120, ultrafine particles are more likely to adhere to or aggregate with the collision plate 110 than in a structure in which the flow channel is not narrowed. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

In the flow path structure 120, the ultrafine particles are more likely to adhere to or agglomerate with the collision plate 110 than in a structure in which the flow velocities in the air transport direction of the flow path are equal. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

In the present embodiment, the material of the narrowing portions 122, 122 is conductive, but a material other than conductive may be used.

[ 3 rd embodiment ]

Next, the flow path structure of embodiment 3 will be described with reference to fig. 6. The same components as those in embodiment 1 and embodiment 2 are denoted by the same reference numerals and their descriptions are omitted.

As shown in fig. 6, the flow path structure 130 includes a narrowing portion 132 that narrows the flow path 104 of the duct 102, and an -sample conductive collision plate 134 as a collision surface disposed at a position where the air narrowed by the narrowing portion 132 collides.

The narrowing portion 132 includes a conductive plate-like body that is supported by the inner wall surface 112 of the pipe 102 and is disposed so as to protrude into the flow path 104. The narrowing portion 132 is made of metal, for example. A space for passing air is provided between the front end of the constriction 132 and the inner wall surface 112 of the duct 102.

The distance between the front end of the narrowing portion 132 and the inner wall surface 112 of the duct 102 is smaller than the size of the collision plate 134.

The collision plate 134 is disposed so as to face a position downstream of the constriction 132 in the air conveyance direction (the direction of arrow B) and at which a distance between the front end portion of the constriction 132 and the inner wall surface 112 of the duct 102 is provided. The collision plate 134 is made of, for example, metal.

In the flow path structure 130, the same effects can be obtained by the same structure as the flow path structure 120 of embodiment 2.

In the present embodiment, the material of the narrowing portion 132 is conductive, but a material other than conductive may be used.

[ 4 th embodiment ]

Next, the flow path structure of embodiment 4 will be described with reference to fig. 7. The same components as those in embodiments 1 to 3 are denoted by the same reference numerals and their description is omitted.

As shown in fig. 7, in the flow path structure 140, a plurality of (three in the present embodiment) pairs of of flow paths 104 of the narrowed duct 102 are provided along the air conveyance direction (the direction of arrow B) along the narrowed portions 122, and a collision plate 110, and the collision plate 110 is disposed at a position where the air narrowed by the narrowed portions 122, 122 collides.

In the present embodiment, the following configuration is adopted: by narrowing the flow path by the plurality of pairs of narrowing portions 122, the flow velocity of the air is increased toward the downstream side in the air conveyance direction (the direction of arrow B), and the air collides against the collision plate 110.

The flow path structure 140 can obtain the following effects in addition to the effects of the structure equivalent to the flow path structure 120 of embodiment 2. In the flow path structure 140, the ultrafine particles are more likely to adhere to or agglomerate with the collision plate 110 than in a structure in which the flow velocities in the air conveyance direction of the flow path are equal. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

Further, in the flow path structure 140, since a plurality of ultrafine particles are more likely to adhere to or agglomerate with the collision plate 110 than in the structure in which constrictions and collision surfaces are provided, the discharge amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

[ 5 th embodiment ]

Next, the flow path structure of embodiment 5 will be described with reference to fig. 8. The same components as those in embodiments 1 to 4 are denoted by the same reference numerals and their description is omitted.

As shown in fig. 8, in the flow path structure 150, there is provided an electrically conductive narrowed portion 152 which is supported on the side of the inner wall surface 112 of the duct 102 in a plan view and is arranged so as to protrude into the flow path 104, and in the flow path structure 150, there is provided an electrically conductive narrowed portion 154 which is supported on the other side of the inner wall surface 112 of the duct 102 in a plan view and is arranged so as to protrude into the flow path 104 on the downstream side of the narrowed portion 152 in the air transport direction (arrow B direction), a narrowed portion 154 is arranged in a direction intersecting with an extension line of the narrowed portion 152, and a plurality of (three in the present embodiment) narrowed portions 152 and 154 are provided alternately in the air transport direction in the flow path 104.

The air that has collided with the constricted portion 152 is transported along the constricted portion 152 in the direction of the arrow C. The constriction 154 is disposed at a position where the air sent in the direction of arrow C collides. Further, the air that has collided with the constricted portion 154 is transported along the constricted portion 154 in the arrow D direction. The next constriction 152 is arranged at a position where the air conveyed in the direction of arrow D collides. This is repeated, and a plurality of (three in the present embodiment) narrowed portions 152 and 154 are alternately arranged. The narrowed portions 152 and 154 are made of metal, for example.

The angle of the downstream side of the narrowed portions 152 and 154 with respect to the inner wall surface 112 (the angle of the downstream side of the flow path 104 in the air conveyance direction) is preferably 90 ° or less and 10 ° or more, more preferably 80 ° or less and 20 ° or more, and still more preferably 70 ° or less and 30 ° or more.

Fig. 9 is a diagram schematically showing the flow rate of air in the duct 102 in the flow path structure 150. In fig. 9, the denser the point (dot) (the higher the density), the faster the flow rate of air. As shown in fig. 9, a plurality of (three in the present embodiment) the narrowing portions 152 and the narrowing portions 154 are alternately provided along the air conveyance direction in the flow path 104, and thus the flow velocity of the air increases toward the downstream side in the air conveyance direction of the flow path 104. That is, the flow path structure 150 has the following structure: the air flow velocity increases toward the air conveyance direction downstream side of the flow path 104, and the air collides against the narrowed portions 152 and 154.

In addition to the effects of the structure equivalent to the flow path structure 100 of embodiment 1, the flow path structure 150 can obtain the following effects. In the flow path structure 150, the constriction portions 152 and 154 are configured to constrict the flow path 104 by the collision surface. Therefore, the flow path structure 150 is simpler in structure than a structure having a dedicated narrowing member.

In the flow path structure 150, the ultrafine particles are more likely to adhere to or aggregate in the constricted portions 152 and 154 than in a structure in which the flow velocities in the air transport direction of the flow path are equal. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

In the flow channel structure 150, the ultrafine particles are more likely to adhere to or aggregate in the constricted portions 152 and 154 than in the case where the angle of the downstream side of the collision surface with respect to the inner wall surface of the pipe is 90 ° or more. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

[ 6 th embodiment ]

Next, the flow path structure of embodiment 6 will be described with reference to fig. 10. The same components as those in embodiments 1 to 5 are denoted by the same reference numerals and their description is omitted.

As shown in fig. 10, in flow path structure 160, pairs of narrowed portions 162, 162 of flow path 104 provided with narrowed duct 102 and collision plate 110 are arranged at a position where air narrowed by narrowed portions 162, 162 collides, furthermore, in flow path structure 160, pairs of narrowed portions 164, 164 of flow path 104 provided with narrowed duct 102 and collision plate 110 are arranged downstream of narrowed portions 162, 162 and collision plate 110, and collision plate 110 is arranged at a position where air narrowed by narrowed portions 164, 164 collides, furthermore, in flow path structure 160, pairs of narrowed portions 166, 166 of flow path 104 provided with narrowed duct 102 and collision plate 110 are arranged downstream of narrowed portions 164, 164 and collision plate 110, and collision plate 110 is arranged at a position where air narrowed by narrowed portions 166, 166 collides.

The narrowed portions 162 and 162, 164, and 166 include pairs of conductive plate-like bodies, pairs of conductive plate-like bodies are supported at positions facing the inner wall surface 112 of the duct 102 and are disposed so as to protrude into the flow path 104, and the narrowed portions 162 and 162, 164, and 166, 166 are made of metal, for example.

The structure is as follows: the angles of the downstream sides of the narrowed portions 162, 162 with respect to the inner wall surface 112, the angles of the downstream sides of the narrowed portions 164, 164 with respect to the inner wall surface 112, and the angles of the downstream sides of the narrowed portions 166, 166 with respect to the inner wall surface 112 become larger in this order. In other words, the angles of the downstream sides of the narrowed portions 162, 162 with respect to the inner wall surface 112, the angles of the downstream sides of the narrowed portions 164, 164 with respect to the inner wall surface 112, and the angles of the downstream sides of the narrowed portions 166, 166 with respect to the inner wall surface 112 increase toward the downstream side in the air conveying direction (the direction of arrow B).

Further, the following structure is provided: the size (interval) D1 of the narrowed portions 162, the size (interval) D2 of the narrowed portions 164, and the size (interval) D3 of the narrowed portions 166, 166 are narrowed in this order. In other words, the size D2 of the constrictions 164, 164 on the downstream side in the air conveying direction is smaller than the size D1 of the constrictions 162, 162 on the upstream side in the air conveying direction, and the size D3 of the constrictions 166, 166 on the downstream side in the air conveying direction is smaller than the size D2 of the constrictions 164, 164 on the upstream side in the air conveying direction.

The flow path structure 160 is provided with the narrowed portions 162 and 162, the narrowed portions 164 and 164, and the narrowed portions 166 and 166, and thus the flow velocity of the air increases toward the downstream side in the air conveying direction of the flow path 104.

The flow path structure 160 can obtain the following effects in addition to the effects of the structure equivalent to the flow path structure 140 of embodiment 4. In the flow path structure 150, a plurality of ultrafine particles are more likely to adhere to or agglomerate with the collision plate 110 than in a structure in which the sizes (intervals) of the narrowed portions are equal along the air conveyance direction. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

In the present embodiment, three narrowing portions and collision plates are provided, but the number of narrowing portions and collision plates may be changed.

[ 7 th embodiment ]

Next, the flow path structure of embodiment 7 will be described with reference to fig. 11. The same components as those in embodiments 1 to 6 are denoted by the same reference numerals and their description is omitted.

As shown in fig. 11, in flow path structure 170, pairs of narrowed portions 172, 172 of flow path 104 provided with narrowed duct 102 and collision plate 110 are arranged at a position where air narrowed by narrowed portions 172, 172 collides, furthermore, in flow path structure 170, pairs of narrowed portions 174, 174 of flow path 104 provided with narrowed duct 102 and collision plate 110 are arranged downstream of narrowed portions 172, 172 and collision plate 110 arranged at a position where air narrowed by narrowed portions 174, 174 collides, furthermore, in flow path structure 160, pairs of narrowed portions 176, 176 of flow path 104 provided with narrowed duct 102 and collision plate 110 are arranged downstream of narrowed portions 174, 174 and collision plate 110, and collision plate 110 arranged at a position where air narrowed by narrowed portions 176, 176 collides.

The narrowed portions 172 and 172, the narrowed portions 174 and 174, and the narrowed portions 176 and 176 include pairs of electrically conductive plate-like bodies, pairs of electrically conductive plate-like bodies are supported at positions facing the inner wall surface 112 of the duct 102 and are disposed so as to protrude into the flow path 104, and the narrowed portions 172 and 172, the narrowed portions 174 and 174, and the narrowed portions 176 and 176 are made of metal, for example.

The angle of the downstream side of the constrictions 172, 172 with respect to the inner wall surface 112, the angle of the downstream side of the constrictions 174, 174 with respect to the inner wall surface 112, and the angle of the downstream side of the constrictions 176, 176 with respect to the inner wall surface 112 are equal. In the present embodiment, these angles are set to 90 °.

The size (interval) D1 of the narrowed portions 172, the size (interval) D2 of the narrowed portions 174, and the size (interval) D3 of the narrowed portions 176, 176 are reduced in this order. Namely, the following structure is adopted: the size (interval) D1 of the narrowed portions 172, the size (interval) D2 of the narrowed portions 174, and the size (interval) D3 of the narrowed portions 176, 176 become narrower toward the downstream side in the air conveying direction (arrow B direction).

The flow path structure 170 described above can obtain the following effects in addition to the effects of the structure equivalent to the flow path structure 140 of embodiment 4. In the flow path structure 170, a plurality of ultrafine particles are more likely to adhere to or aggregate with the collision plate 110 than in a structure in which the size (interval) of the constriction is equal along the air conveyance direction. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

[ 8 th embodiment ]

Next, the flow path structure of embodiment 8 will be described with reference to fig. 12. The same components as those in embodiments 1 to 7 are denoted by the same reference numerals and their description is omitted.

As shown in fig. 12, the flow path structure 180 is provided with a narrowing portion 186 that narrows the flow path 184 of the duct 182. The constriction 186 has the following structure: the flow path 184 is narrowed by gradually narrowing the width-directional dimension (distance) of the inner wall 186A of the duct 182 toward the downstream side in the air conveyance direction (the arrow B direction). A plurality of (three in the present embodiment) collision plates 110 having the same size are provided inside the duct 182.

The flow path structure 180 described above can obtain the following effects in addition to the effects of the structure equivalent to the flow path structure 140 of embodiment 4. The flow path structure 180 has a simpler structure than a structure having a dedicated narrowing member.

[ 9 th embodiment ]

Next, a flow path structure according to embodiment 9 will be described with reference to fig. 13. The same components as those in embodiments 1 to 8 are denoted by the same reference numerals and their description is omitted.

As shown in fig. 13, the flow path structure 190 is provided with a plurality of (three in the present embodiment) conductive collision plates 192, 194, 196 arranged in a direction intersecting the air conveyance direction (the direction of arrow B) inside the duct 102. The collision plates 192, 194, 196 are configured such that their sizes increase toward the downstream side in the air conveyance direction (the direction of arrow B). Thus, the distance between the inner wall surface 112 of the duct 102 and the collision plates 192, 194, and 196 becomes narrower toward the downstream side in the air conveyance direction (the direction of arrow B).

In the flow path structure 190, the distance between the inner wall surface 112 of the duct 102 and the collision plates 192, 194, and 196 is narrowed toward the downstream side in the air conveyance direction (the direction of arrow B), and thus the flow velocity becomes larger toward the downstream side in the air conveyance direction.

The flow path structure 190 can obtain the following effects in addition to the effects of the structure equivalent to the flow path structure 100 of embodiment 1. In the flow path structure 190, the ultrafine particles are more likely to adhere to or aggregate on the collision plates 192, 194, and 196 than in a structure in which the flow velocities in the air conveyance direction of the flow path are equal. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

[ 10 th embodiment ]

Next, a flow path structure according to embodiment 10 will be described with reference to fig. 14. The same components as those in embodiments 1 to 9 are denoted by the same reference numerals and their description is omitted.

As shown in fig. 14, in the flow path structure 200, a plurality of (four in the present embodiment) narrowed portions 152 and narrowed portions 154 are alternately provided along the air conveyance direction in the flow path 104, the narrowed portions 152 are provided on the side of the inner wall surface 112 of the duct 102 and the narrowed portions 154 are provided on the other side of the inner wall surface 112 of the duct 102 in a plan view, and as described above, the narrowed portions 152 and 154 are examples of collision surfaces, and the flow path 104 is narrowed by the collision surfaces.

The flow path structure 200 has the following structure: the intervals (distances) L1, L2, L3 between the bottom ends of the narrowing portions 154 in the air transporting direction (arrow B direction) become narrower toward the downstream side of the air transporting direction (arrow B direction). Similarly, the intervals (distances) between the bottom ends of the narrowing sections 152 in the air transport direction (the direction of arrow B) are also set to L1, L2, and L3, and the following structures are provided: the interval (distance) between the bottom ends of the narrowing portions 152 also becomes narrower toward the downstream side in the air conveyance direction (the arrow B direction).

In addition to the effects of the structure equivalent to the flow path structure 150 of embodiment 5, the flow path structure 200 can obtain the following effects. In the flow path structure 200, the ultrafine particles on the downstream side are more likely to adhere to or agglomerate in the constricted portions 152 and 154 than in a structure in which the intervals (distances) between the collision surfaces in the air transport direction are equal as they go to the downstream side in the air transport direction. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

[ embodiment 11 ]

Next, the flow path structure of embodiment 11 will be described with reference to fig. 15. The same components as those in embodiments 1 to 10 are denoted by the same reference numerals and their description is omitted.

As shown in fig. 15, in the flow path structure 210, in a plan view, a plurality of (three in the present embodiment) narrowing portions 212A, 212B, 212C are provided on the side of the inner wall surface 112 of the duct 102 toward the downstream side in the air conveyance direction (the arrow B direction), and in the flow path structure 210, in a plan view, a plurality of (three in the present embodiment) narrowing portions 214A, 214B, 214C are provided on the other side of the inner wall surface 112 of the duct 102 toward the downstream side in the air conveyance direction (the arrow B direction), in the flow path structure 200, in other words, in the flow path structure 104, narrowing portions 212A, 212B, 212C on the side of the inner wall surface 112 and narrowing portions 214A, 214B, 214C on the other side of the inner wall surface 112 are alternately provided toward the downstream side in the air conveyance direction, that the narrowing portions 212A, 214A, 212B, 214B, 212C, 214A, 214B, 214C are sequentially provided toward the flow path 104 toward the downstream side in the air conveyance direction, and the flow path structure is a collision example.

The structure is as follows: an angle θ 1 of the downstream side of the constriction 212A with respect to the inner wall surface 112, an angle θ 2 of the downstream side of the constriction 212B with respect to the inner wall surface 112, and an angle θ 3 of the downstream side of the constriction 212C with respect to the inner wall surface 112 become larger toward the downstream side in the air conveying direction (i.e., θ 1 < θ 2 < θ 3). For example, the angle θ 1 of the downstream side of the narrowed portion 212A with respect to the inner wall surface 112 is preferably 10 ° or more, and the angle θ 3 of the downstream side of the narrowed portion 212C with respect to the inner wall surface 112 is preferably 90 ° or less.

Similarly, the following structure is adopted: the angle of the downstream side of the constriction 214A with respect to the inner wall surface 112, the angle of the downstream side of the constriction 214B with respect to the inner wall surface 112, and the angle of the downstream side of the constriction 212C with respect to the inner wall surface 112 increase toward the downstream side in the air conveying direction.

The flow path structure 210 described above can obtain the following effects in addition to the effects of the structure equivalent to the flow path structure 150 of embodiment 5. In the flow channel structure 210, the ultrafine particles are more likely to adhere to or aggregate in the constrictions 212B, 212C, 214B, and 214C on the downstream side than in a structure in which the angle of the downstream side of the collision surface with respect to the inner wall surface of the duct is equal. Therefore, the amount of ultrafine particles discharged to the outside of the image forming apparatus 10 is reduced.

[ 12 th embodiment ]

Next, the flow path structure according to embodiment 12 will be described with reference to fig. 16(a) to 16 (C). The same components as those in embodiments 1 to 11 are denoted by the same reference numerals and their description is omitted.

Fig. 16(a) to 16(C) show flow path structures 220, 230, and 240 in which the angle of the upstream side of the constriction with respect to the inner wall surface 112 of the duct 102 is changed, as shown in fig. 16(a), in the flow path structure 220, a plurality of (three in the present embodiment) constrictions 222 and 224 are alternately provided along the air conveyance direction in the flow path 104, the constrictions 222 are provided on the side of the inner wall surface 112 of the duct 102, the constrictions 224 are provided on the other side of the inner wall surface 112 of the duct 102 in a plan view, the constrictions 222 and 224 are examples of collision surfaces, the angle θ 4 of the upstream side of the constrictions 222 and 224 with respect to the inner wall surface 112 of the duct 102 is set to 135 °, the constrictions 222 and 224 include metal plates, and are joined to the inner wall surface 112 by welding or the like.

As shown in fig. 16B, in the flow path structure 230, a plurality of (three in the present embodiment) narrowed portions 232 and narrowed portions 234 are alternately provided along the air transport direction in the flow path 104, the narrowed portions 232 are provided on the side of the inner wall surface 112 of the duct 102 and the narrowed portions 234 are provided on the other side of the inner wall surface 112 of the duct 102 in a plan view, the narrowed portions 232 and 234 are examples of collision surfaces, the angle θ 5 of the upstream sides of the narrowed portions 232 and 234 with respect to the inner wall surface 112 of the duct 102 is set to 90 °, the narrowed portions 232 and 234 are made of metal plates, and are joined to the inner wall surface 112 by welding or the like.

As shown in fig. 16C, in the flow path structure 240, a plurality of (three in the present embodiment) narrowed portions 242 and narrowed portions 244 are alternately provided along the air transport direction in the flow path 104, the narrowed portions 242 are provided on the side of the inner wall surface 112 of the duct 102, the narrowed portions 244 are provided on the other side of the inner wall surface 112 of the duct 102 in a plan view, the narrowed portions 242 and 244 are examples of collision surfaces, the angle θ 6 of the upstream sides of the narrowed portions 242 and 244 with respect to the inner wall surface 112 of the duct 102 is set to 45 °, the narrowed portions 242 and 244 include metal plates, and are joined to the inner wall surface 112 by welding or the like.

Fig. 17 shows a relationship between an angle of the upstream side of the constriction portion (metal plate) with respect to the inner wall surface 112 of the duct 102 and an ultrafine particle (UFP) collection rate at the outlet portion of the duct 102. The capture rate here means a ratio of the amount of the captured ultrafine particles when the whole ultrafine particles are 100. As shown in fig. 17, the larger the angle of the upstream side of the constriction (metal plate) with respect to the inner wall surface 112 of the duct 102, the larger the capture rate of the ultrafine particles (UFPs). In the above experiment, in the case of the flow channel structure 220 in which the angle θ 4 of the upstream side of the narrowing portions 222, 224 with respect to the inner wall surface 112 of the duct 102 was 135 °, the capture rate of ultrafine particles (UFPs) was the greatest.

In other words, when the angle of the downstream side of the constriction portion (metal plate) with respect to the inner wall surface 112 of the duct 102 is small, the capture rate of the ultrafine particles (UFP) becomes large. According to the experimental result, the angle of the downstream side of the narrowed portion (metal plate) with respect to the inner wall surface 112 of the duct 102 is preferably 90 ° or less, for example.

[ 13 th embodiment ]

Next, the flow path structure according to embodiment 13 will be described with reference to fig. 18(a) to 18 (C). The same components as those in embodiments 1 to 12 are denoted by the same reference numerals and their description is omitted.

Fig. 18 a to 18C show flow path structures 260, 264, and 268 for changing the position of a duct inlet for sucking air around the fixing device 50, the fixing device 50 includes, as shown in fig. 18 a, a heating rotor 51A, a pressurizing rotor 51B, a frame 252 covering a range of the heating rotor 51A other than the side in contact with the pressurizing rotor 51B, and a frame 252 covering a range of the pressurizing rotor 51B other than the heating rotor 51A side, the flow path structure 260 includes a duct 262 for sucking air around the fixing device 50 by a fan (not shown), and in the present embodiment, the inlet 262A of the duct 262 is provided on the downstream side of the heating rotor 51A in the conveying direction (direction of arrow P1) of the sheet P.

As shown in fig. 18B, the flow path structure 264 includes a duct 266 for sucking air around the fixing device 50 by a fan (not shown). In the present embodiment, inlet 266A of duct 266 is provided near the center of heating rotor 51A (directly beside heating rotor 51A) in the conveyance direction of paper P (direction of arrow P1).

As shown in fig. 18C, the flow path structure 268 includes a duct 270 for sucking air around the fixing device 50 by a fan (not shown). In the present embodiment, inlet 270A of duct 270 is located at a position surrounding heating rotor 51A in the conveyance direction of paper P (the direction of arrow P1).

The configuration of the collision plate as a collision surface provided in the flow path in the ducts 262, 266, 270 is the same as the collision plate 110 of the flow path structure 100 of embodiment 1.

The capture rate of ultrafine particles at the outlet portion of the ducts 262, 266, 270 was measured using the flow channel structures 260, 264, 268 shown in fig. 18(a) to 18(C), and as a result, it was confirmed that: the flow channel structure 268 shown in FIG. 18(C) has the largest rate of collection of ultrafine particles, and the flow channel structure 264 shown in FIG. 18(B) has the next largest rate of collection of ultrafine particles.

Moreover, it was confirmed that: the flow channel structure 268 shown in fig. 18(C) has a larger collection rate of ultrafine particles than the flow channel structure 264 shown in fig. 3 (B) has for the inlet side of the fixing device 50, and the collection rate of ultrafine particles is the same as the flow channel structure 268 shown in fig. 18 (C).

While the present invention has been described in detail with reference to the specific embodiments, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments, and various other embodiments can be made within the scope of the present invention.