JP6610153B2 - Blower tube, blower, and image forming apparatus - Google Patents

Description

  The present invention relates to a blower tube, a blower, and an image forming apparatus.

  In recent years, the present applicant has made proposals related to the following blower devices and the like.

  For example, as a blower, it is arranged in a state where it faces a longitudinal portion of an elongated target structure to be blown with air taken in from the blower and air taken in from the blower. An outlet that flows out along a direction orthogonal to the direction, and a main body portion in which a passage space for flowing air is formed between the inlet and the outlet, and the outlet is formed on the target structure. A direction in which air flows in the passage space of the main body portion of the blast pipe that is formed in a long opening shape parallel to the longitudinal portion, and the inlet and the outlet are formed in different opening shapes. A plurality of restraining portions for restraining air flow, and the most downstream restraining portion provided at the most downstream portion of the restraining portion in the direction of flowing air in the passage space, Proposes a blower using a blowing tube a channel space downstream of the site plurality of ventilation portions are formed so as to be in a state closes breathable member dotted (Patent Document 1). Examples of the target structure include a corona discharger.

  Moreover, as a ventilation pipe | tube used for an air blower, in the said assumption ventilation pipe | tube, as one of the said several suppression part, the ventilation | gas_flowing which a several ventilation part is dotted with the passage space in the exit in the exit of the said passage part Provided with an outlet restraining portion configured to be in a state of being blocked by the adhesive member, and at least in a short direction perpendicular to the longitudinal direction in a region along the longitudinal direction of the opening shape of the outlet in the breathable member of the outlet restraining portion. A blower pipe is proposed in which the air permeability of an end region existing on one end side is set to a value smaller than the air permeability of a region other than the end region (Patent Document 2 below).

JP 2013-88731 A JP 2013-134812 A

  The invention is arranged in such a way that it faces an inlet and a longitudinal part that is long in one direction of the target structure to which air taken in from the inlet is blown, and extends along the longitudinal part of the target structure; An outlet having an opening shape different from the inlet, a passage portion formed by bending the passage space between the inlet and the outlet at least once in the middle, and a direction in which air flows in the passage space. As a blower pipe provided with a plurality of restraining portions that are provided at different sites and restrain the flow of air, the first restraining portion that is present in the middle of the bending passage portion, the upstream opening end of the gap in the first restraining portion. Even if the air volume to be blown to the target structure is increased as compared with the case where at least the upper side is not provided with a shape that protrudes into the passage space of the front passage portion, it is taken from the entrance. The pressure loss of the air until it is inserted and discharged from the outlet is increased to provide a blower pipe that can reduce the unevenness of the wind speed in the longitudinal direction of the air discharged from the outlet, and using the blower pipe A blower and an image forming apparatus are provided.

The blast tube of this invention (A1)
An inlet for taking in air;
It is arranged in a state facing a long longitudinal part in one direction of the target structure to which air taken in from the inlet is blown, and extends along the longitudinal part of the target structure and has an opening shape different from that of the inlet. An exit,
A passage portion formed in a state where a passage space for flowing air by connecting between the inlet and the outlet is bent at least once in the middle;
A plurality of suppressing portions that are provided in different portions in the direction of flowing air in the passage space of the passage portion and suppress the flow of air;
With
The passage portion has a first bent passage portion that is bent at a position closest to the inlet, and a front passage portion that exists immediately before an upstream side in the direction of flowing air of the first bent passage portion,
One of the plurality of restraining portions is a first restraining portion having a structure in which a gap extending in the transverse direction is cut off across a part of the passage space in the first bending passage portion and extends.
In the first suppression part, at least the upper side of the upstream opening end in the direction of flowing the air in the gap constitutes an inner wall upper surface constituting the passage space in the front passage part and the blocking part of the first suppression part. It is provided to have a shape that protrudes into the passage space of the front passage portion from a virtual vertical plane orthogonal to the upper surface of the inner wall at a position where the inner wall surface on the upstream side intersects ,
The shape of the first restraining portion that protrudes into the front passage portion has an inclined inner wall surface that is inclined over the entire surface on the downstream side in the air flow direction as it moves upward from at least the upper opening end of the gap. It is configured .

The blast tube of this invention (A2)
An inlet for taking in air;
It is arranged in a state facing a long longitudinal part in one direction of the target structure to which air taken in from the inlet is blown, and extends along the longitudinal part of the target structure and has an opening shape different from that of the inlet. An exit,
A passage portion formed in a state where a passage space for flowing air by connecting between the inlet and the outlet is bent at least once in the middle;
A plurality of suppressing portions that are provided in different portions in the direction of flowing air in the passage space of the passage portion, and suppress the flow of air;
With
The passage portion has a first bent passage portion that is bent at a position closest to the inlet, and a front passage portion that exists immediately before an upstream side in the direction of flowing air of the first bent passage portion,
One of the plurality of restraining portions is a first restraining portion having a structure in which a gap extending in the transverse direction is cut off across a part of the passage space in the first bending passage portion and extends.
In the first suppression part, at least the upper side of the upstream opening end in the direction of flowing the air in the gap constitutes an inner wall upper surface constituting the passage space in the front passage part and the blocking part of the first suppression part. It is provided to have a shape that protrudes into the passage space of the front passage portion from a virtual vertical plane orthogonal to the upper surface of the inner wall at a position where the inner wall surface on the upstream side intersects,
The shape of the first restraining portion that protrudes into the passage space extends beyond the virtual vertical surface into the front passage portion and protrudes in a state parallel to the direction of the path length of the gap. A plate is provided .
The blower pipe of this invention (A3) is the blower pipe of the aforementioned invention A1, wherein the shape of the first restraining part protruding into the passage space is extended from the lower end of the inclined inner wall surface into the front passage part. The protruding plate is provided in a state parallel to the direction of the path length of the gap in the first suppressing portion .
The blast pipe of this invention (A4) is the blast pipe according to any one of the above inventions A1 to A3 , wherein the shape of the first restraining part protruding in the passage space is upstream in the direction in which the air in the gap flows. It is comprised so that it may exist in both the upper side and lower side of a side opening end .
The blast pipe of this invention (A5) is the blast pipe of the above-mentioned invention A4 , wherein the shape of the first suppression part protruding into the passage space and existing on both the upper side and the lower side is the air in the passage space. It exists so that it may exist in the state which becomes line symmetrical about the said clearance gap in the same position in the flow direction .

The blower of this invention (B) is provided with the air blower which sends air, and the air blow pipe in any one of said invention A1 to A5 which takes in the air sent from the said air blower.
The image forming apparatus of the present invention (C) includes: a target structure having a long longitudinal portion in one direction to which air is to be blown; and a blower that blows air on a longitudinal portion of the target structure. And the air blower is configured by the air blower of the invention B.

According to the blast pipe of the invention A1, at least the upper side of the upstream opening end of the gap in the first restraining portion projects into the passage space of the near passage portion of the first restraining portion that is present in the middle of the bending passage portion. In the case where it is not provided so as to have an existing shape, or an inclined inner wall surface that inclines over the entire surface on the downstream side in the direction in which air flows as the shape that protrudes into the passage space of the passage portion in front of the first suppression portion moves upward. Even if the air volume to be blown to the target structure is increased compared to the case where the target structure is not configured, the pressure loss of the air from the inlet to the outlet is increased and the pressure from the outlet is increased. Unevenness of the wind speed in the longitudinal direction of the discharged air can be reduced.

In the blast tube of the invention A2, the first suppression portion that is present in the middle of the bending passage portion, the passage of the passage portion in front of the imaginary vertical plane is at least above the upstream opening end of the gap in the first suppression portion. When it is not provided so as to have a shape that protrudes into the space, or the shape that protrudes into the passage space of the front passage portion of the first suppression portion extends into the passage space of the front passage portion and protrudes Compared to the case where a projecting plate that is in a state parallel to the direction of the path length of the gap is not provided, even if the amount of air to be blown to the target structure is increased, it is taken in from the inlet and discharged from the outlet. The pressure loss of the air until it is increased can increase the unevenness of the wind speed in the longitudinal direction of the air discharged from the outlet.
In the blower pipe of the invention A3, the shape that protrudes into the passage space of the front passage portion of the first suppressing portion is provided with a protruding plate that protrudes from the lower end of the inclined inner wall surface into the passage space of the front passage portion. in comparison with If not, it is possible to increase more the pressure loss of the air to be discharged from the outlet incorporating the inlet mouth, to further reduce the unevenness of the wind speed in the longitudinal direction of the air discharged from the outlet .
In the blast pipe of the invention A4, when the shape that protrudes and exists in the passage space of the front passage portion of the first suppression portion is not present on both the upper side and the lower side of the upstream opening end of the gap. As compared with the above, the pressure loss of the air from the inlet to the outlet is further increased, and the unevenness of the wind speed in the longitudinal direction of the air discharged from the outlet can be further reduced.
In the blower pipe of the invention A5, the shape that protrudes into the passage space of the front passage portion of the first suppressing portion and exists on both the upper side and the lower side has the gap at the same position in the direction of flowing air in the passage space. sandwiched therebetween as compared with the case not be configured to present in a state to be line symmetry, it is possible to further reduce the wind speed fluctuation of in the longitudinal direction of the air discharged from the exit.

According to the blower device of the invention B, with respect to the first suppression portion that is present in the middle of the bent passage portion in the blower pipe, at least the upper side of the upstream opening end of the gap in the first suppression portion is in the passage space of the front passage portion. In the case where it is not provided so as to have a shape that protrudes to the front, or the shape that protrudes in the passage space of the passage portion in front of the first restraining portion is inclined to the entire downstream side in the direction in which air flows as it leaves upward When the inner wall surface is not configured, or a projecting plate that projects into the passage space of the front passage portion of the first suppression portion and protrudes into the passage space of the front passage portion is provided. as compared with the case not, also increases the volume of the air to be blown into the objective structure at the blower tube, the pressure loss of the air to be discharged from the outlet incorporating the inlet of the blower tube is increased, It is possible to reduce the wind speed fluctuation of in the longitudinal direction of the air discharged from the outlet of the wind pipe.

According to the image forming apparatus of the invention C, with respect to the first suppression portion that is present in the middle of the bending passage portion in the blower pipe of the blower, at least the upper side of the upstream opening end of the gap in the first suppression portion is the front passage portion. If it is not provided so as to have a shape that protrudes into the passage space, or the shape that protrudes into the passage space of the passage portion in front of the first restraining part moves upward, the air flows in the downstream direction. In the case where the inclined inner wall surface that is inclined over the entire surface does not exist, or a projecting plate that protrudes into the passage space of the front passage portion of the first suppression portion and protrudes into the passage space of the front passage portion is provided. as compared with the case where provided it does not constitute, also increases the volume of the air to be blown into the objective structure in the blower tube of the blowing device, an empty until discharged from the outlet incorporating the inlet of the blower pipe Pressure loss is increased, it is possible to reduce the unevenness of the wind speed in the longitudinal direction of the air discharged from the outlet of the blower tube.

1 is an explanatory diagram illustrating an outline of an image forming apparatus using a blower according to Embodiment 1 and the like. FIG. 2 is a perspective view illustrating an outline of a charging device provided in the image forming apparatus of FIG. 1. It is a perspective view which shows the outline | summary of the air blower applied to the charging device of FIG. It is sectional explanatory drawing which follows the QQ line of the air blower (air blower tube) of FIG. It is the schematic which shows a state when the air blower of FIG. 3 is seen from the upper direction. It is the schematic which shows a state when the air blower of FIG. 3 is seen from the downward direction (exit). It is explanatory drawing which shows the operation state etc. of the air blower of FIG. It is explanatory drawing which shows the principal part of the operation state of FIG. 3 only with the shape of the channel | path part. It is the table | surface and graph which show the test regarding the performance characteristic of various ventilation pipes (Example 1, Example 2, the ventilation pipe of a comparative example, and a reference example). It is sectional explanatory drawing which shows the outline | summary of the air blower (blower pipe) which concerns on Embodiment 2. FIG. It is explanatory drawing which shows the principal part of the operation state of the ventilation pipe | tube of FIG. 10 only with the shape of the channel | path part. It is explanatory drawing which shows the other structural example of a blast pipe only by the shape of the channel | path part. It is explanatory drawing which shows another structural example of a ventilation pipe only by the shape of the channel | path part. It is explanatory drawing which shows the principal part of the operation state of the blast pipe of Fig.13 (a) only by the shape of the channel | path part. It is sectional explanatory drawing which shows the outline | summary of the air blower (blower pipe) of a comparative example. It is sectional explanatory drawing which shows the outline | summary of the air blower (blower pipe) of a reference example.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the accompanying drawings.

[Embodiment 1]
1 to 4 show a blow duct as an example of a blow pipe according to the first embodiment, a blower using the blow duct, and an image forming apparatus. FIG. 1 shows an outline of the image forming apparatus, FIG. 2 shows a charging device as an example of a long target structure to be blown with air by the blower duct or blower, and FIG. 3 shows the blower duct or blower. The outline of the apparatus is shown, and FIG. 4 shows the internal structure of the air duct and the like.

<Configuration of image forming apparatus>
As shown in FIG. 1, the image forming apparatus 1 forms a toner image composed of toner as a developer in an internal space of a casing 10 composed of a support frame, an exterior cover, and the like. As an example, an image forming unit 20 for transferring to the recording paper 9, a paper feeding device 30 for storing and conveying the recording paper 9 supplied to the image forming unit 20, and a toner image formed by the image forming unit 20 are recorded on the recording paper. A fixing device 35 and the like for fixing to 9 are arranged.

  The image forming unit 20 is configured using, for example, a known electrophotographic method. The image forming unit 20 according to the first embodiment includes a photosensitive drum 21 that is rotationally driven in a direction indicated by an arrow A, a charging device 4 that charges a peripheral surface serving as an image forming area of the photosensitive drum 21 to a required potential, An exposure device 23 that forms an electrostatic latent image by irradiating light (dotted line with arrows) based on image information (signal) input from the outside onto the charged peripheral surface of the photosensitive drum 21 and the electrostatic latent image Is developed with toner to form a toner image, a transfer device 25 for transferring the toner image from the photosensitive drum 21 to the recording paper 9, toner remaining on the peripheral surface of the photosensitive drum 21 after transfer, etc. And a cleaning device 26 that removes unnecessary materials and cleans them.

  Among these, as the charging device 4, one constituted by a corona discharger is used. As shown in FIG. 2 and the like, the charging device 4 composed of this corona discharger is constituted by a so-called scorotron type corona discharger.

  That is, the charging device 4 is an enclosing member having an external shape having a rectangular top plate 40a and side plates 40b and 40c hanging downward from a long side portion extending along the longitudinal direction B of the top plate 40a. The shield case 40 as an example, two end support members (not shown) attached to both end portions (short side portions) in the longitudinal direction B of the shield case 40, and the shield case between the two end support members The two corona discharge wires 41A and 41B, which are present in a long internal space along the longitudinal direction B of 40 and are attached so as to be stretched substantially in parallel, and the lower opening 44 for discharge of the shield case 40, A porous group attached to the corona discharge wires 41 </ b> A and 41 </ b> B and the peripheral surface of the photosensitive drum 21 so as to substantially cover the lower opening 44. Head electrode and a (field adjustment plate) 42. Reference numeral 40 d shown in FIG. 4 and the like is a partition plate that divides the space in which the two corona discharge wires 41 </ b> A and 41 </ b> B are arranged along the longitudinal direction B of the shield case 40. The lower opening 44 is formed so that its opening shape is rectangular.

  Further, the charging device 4 is in a state in which the two corona discharge wires 41A and 41B are opposed to the peripheral surface of the photosensitive drum 21 with a predetermined interval (for example, a discharge gap) and the rotation axis of the photosensitive drum 21. It is arranged so as to exist at least in a state facing the image forming region along the direction. Further, when the charging device 4 is in an image forming operation, a charging voltage is supplied to each of the corona discharge wires 41A and 41B (between the photosensitive drum 21) from a power supply device (not shown). .

  Further, as the charging device 4 is used, the corona discharge wires 41A and 41B and the grid electrode 42 are coated with substances (such as paper dust of the recording paper 9, discharge products generated by corona discharge, and external additives of toner). Unnecessary materials) may adhere and become contaminated. As a result, corona discharge may not be performed sufficiently or uniformly, and charging defects such as uneven charging may occur. For this reason, the charging device 4 is supplied with air toward the corona discharge wires 41A and 41B and the grid electrode 42 for the purpose of preventing or suppressing unnecessary substances from adhering to the corona discharge wires 41A and 41B and the grid electrode 42. A blower 5 for blowing is also provided. Further, the top plate 40 a of the shield case 40 of the charging device 4 is formed with an opening 43 for taking in air sent from the blower device 5. The opening 43 is formed so that the opening shape is rectangular. The details of the blower 5 will be described later.

  The paper feeding device 30 includes a paper storage body 31 that stores a plurality of recording papers 9 of a required size and type used for image formation in a stacked state, and a recording that is stored in the paper storage body 31. A feeding device 32 that feeds the paper 9 one by one toward the conveyance path is provided, and the recording paper 9 is fed one by one when the paper feeding time comes. A plurality of paper containers 31 are provided according to the usage mode. A two-dot chain line with an arrow in FIG. 1 indicates a conveyance path in which the recording paper 9 is mainly conveyed and moved in the internal space of the housing 10. The conveyance path of the recording paper 9 includes a plurality of paper conveyance roll pairs 33a and 33b, a conveyance guide member (not shown), and the like.

  The fixing device 35 has a roll shape, a belt shape, or the like in which the surface temperature is heated and held at a required temperature by a heating unit in a housing 36 in which an introduction port and a discharge port through which the recording paper 9 passes are formed. A heating rotator 37 and a pressurizing rotator 38 such as a roll form or a belt form that are driven to rotate in contact with a required pressure so as to be substantially along the axial direction of the heating rotator 37 are provided. In the fixing device 35, a contact portion formed by contact between the heating rotator 37 and the pressing rotator 38 is configured as a fixing processing unit that performs a required fixing process (heating and heating). Fixing is performed by introducing the recording sheet 9 after transferring the toner image to the contact portion and passing it therethrough.

  Image formation by the image forming apparatus 1 is performed as follows. Here, a basic image forming operation when an image is formed on one side of the recording paper 9 will be described as a representative.

  In the image forming apparatus 1, when a control device (not shown) receives an image forming operation start command, in the image forming unit 20, the peripheral surface of the photosensitive drum 21 that starts rotating is set to a predetermined polarity and potential by the charging device 4. Charged. At this time, in the charging device 4, charging voltages are respectively applied to the two corona discharge wires 41 </ b> A and 41 </ b> B, and an electric field is formed between the corona discharge wires 41 </ b> A and 41 </ b> B and the peripheral surface of the photosensitive drum 21. In this state, corona discharge is generated, whereby the peripheral surface of the photosensitive drum 21 is charged to a required potential. At this time, the charging potential of the photosensitive drum 21 is adjusted by the grid electrode 42.

  Subsequently, the charged peripheral surface of the photosensitive drum 21 is exposed based on image information from the exposure device 23 to form an electrostatic latent image having a required potential. Thereafter, when the electrostatic latent image formed on the photosensitive drum 21 passes through the developing device 24, the electrostatic latent image is developed with the toner charged to a required polarity supplied from the developing roll to be visualized as a toner image. Is done.

  Next, when the toner image formed on the photosensitive drum 21 is conveyed to the transfer position facing the transfer device 25 by the rotation of the photosensitive drum 21, the toner image passes through the conveyance path from the paper supply device 30 in accordance with this timing. Then, the image is transferred to the recording paper 9 supplied by the transfer action of the transfer device 25. The peripheral surface of the photosensitive drum 21 after the transfer is cleaned by a cleaning device 26.

  Subsequently, the recording paper 9 onto which the toner image has been transferred in the image forming unit 20 is transported so as to be introduced into the fixing device 35 after being peeled off from the photosensitive drum 21, and added to the heating rotator 37 of the fixing device 35. When passing through the contact portion of the pressure rotating body 38, the toner image is melted and fixed on the recording paper 9 by being heated under pressure. After the fixing is completed, the recording paper 9 is discharged from the fixing device 35 and is conveyed and stored in a paper discharge storage unit (not shown) provided outside the housing 10 or the like.

  In this way, a single color image composed of one color toner is formed on one side of one sheet of recording paper 9, and the basic image forming operation is completed. When there is an instruction for a plurality of image forming operations, the above-described series of operations are similarly repeated for the number of sheets.

<Configuration of blower device>
Next, the blower 5 will be described.

  As shown in FIG. 1, FIG. 3, and the like, the blower 5 includes a blower 50 having a rotating fan that sends air, and a charging device 4 that is an example of a structure to be blown by taking in air sent from the blower 50. And a blower duct 51 </ b> A that guides and discharges the air.

As the blower 50, for example, a radiant flow type blower fan is used. Further, the blower 50 is driven and controlled so as to send a required amount of air.
Further, as shown in FIGS. 3 to 6 and the like, the air duct 51A is provided with an inlet 52 for taking in air sent from the blower 50 and one of the long charging devices 4 to which air taken in from the inlet 52 should be blown. An outlet 53 that is disposed in a state of facing a portion in the longitudinal direction B that is long in the direction (for example, the opening 43) and discharges the air so as to flow along a direction orthogonal to the longitudinal direction B, and the inlet 52 and the outlet 53 The passage space (body portion) 54 formed in a state where the passage space TS for flowing air while being connected is bent twice in the middle, and a portion different in the direction of air flow in the passage space TS of the passage portion 54. It is provided and has a shape having two suppression portions 61 and 62 that suppress the flow of air.

  The inlet 52 of the air duct 51A is formed such that the entire opening shape thereof is, for example, a slightly horizontally long rectangle. A connection duct 55 for connecting the inlet 52 and the blower 50 and sending the air generated by the blower 50 to the inlet 52 is attached to the inlet 52 of the blower duct 51A (FIG. 3).

  The outlet 53 of the air duct 51A has an elongated shape in which the entire opening shape is parallel to a portion in the longitudinal direction B of the charging device 4 (in this example, the opening 43 of the shield case 40). It is formed as follows. As shown in FIGS. 4, 6, etc., the outlet 53 in the actual form 1 is from the entire area of the bottom surface portion (terminal portion) of the portion (second bending passage portion 54 </ b> C) located on the outlet 53 side of the passage portion 54. Is also formed in a state where the opening area becomes a little narrow.

  The passage portion 54 of the air duct 51A includes an introduction passage portion 54A, a first bending passage portion 54B, and a second bending passage portion 54C, as shown in FIGS.

  One end portion of the introduction passage portion 54A is opened by providing an inlet 52, and the other end portion is closed, and the whole is substantially parallel to the longitudinal direction B of the outlet 53 (same as the longitudinal direction B of the charging device 4). And a rectangular tube-shaped passage portion formed so as to extend linearly. 54 A of this introduction channel | path parts become a near channel | path part which exists just before the upstream of the direction (For example, the direction shown by arrow E1a, E2a illustrated in FIG. 7) which flows the air of the 1st bending channel | path part 54B.

  The first bent passage portion 54B extends from a portion (in the middle) near the other end of the introduction passage portion 54A in a state bent substantially at a right angle in a substantially horizontal direction (a direction substantially parallel to the direction indicated by the coordinate axis X). It is the square channel-shaped bending channel | path part formed in. Further, the first bent passage portion 54B has the same passage space TS as the introduction passage portion 54A, and expands only the width (dimension in the longitudinal direction B) to enlarge the entire passage sectional area. It has become a passage part. The first bent passage portion 54B is a bent passage portion that is bent at a position closest to the inlet 52 in the blower duct 51A.

  The second bending passage portion 54C is bent in a vertical direction (a direction substantially parallel to the direction indicated by the coordinate axis Y) from the downstream end of the first bending passage portion 54B in the direction in which the air flows, and is charged by the charging device 4. It is the bending channel | path part extended and formed so that it may approach. Further, the second bent passage portion 54C is a bent passage portion that is bent downwardly with the width of the passage space TS (dimension in the longitudinal direction B) being the same as that of the first bent passage portion 54B. ing. An outlet 53 having the above-described configuration is provided at the terminal end of the second bending passage portion 54C.

  One restraining portion 61 of the air duct 51A has a structure in which a gap 64 that cuts off part of the passage space TS in the first bending passage portion 54B and extends linearly in the transverse direction exists. 1 suppression part 61A is provided.

  Specifically, for example, the first suppressing portion 61A does not change the outer shape of the first bending passage portion 54B, and the height direction (the arrow of the coordinate axis Y is within the passage space TS of the first bending passage portion 54B. The plate-shaped blocking member 65 provided with a gap 64 having a required distance d1 at a position on the lower end side in the direction indicated by the arrow is arranged in a state of crossing. In the first embodiment, the blocking member 65 is arranged so as to be parallel to the longitudinal direction B in the passage space TS and to be in a state where a gap 64 is present below the blocking member 65.

  As shown in FIG. 4 and the like, the first suppressing portion 61A in the first embodiment is configured such that the upper side 64c of the upstream side open end 64a existing on the upstream side in the direction of flowing air in the gap 64 is a front passage portion. An imaginary vertical plane VL orthogonal to the inner wall upper surface 54t at a position Pu where the inner wall upper surface 54t constituting the upper surface of the passage space TS1 and the upstream inner wall surface 65a constituting the blocking portion of the first suppressing portion 61A intersect. It is provided so as to have a shape that protrudes into the passage space TS1 of the front passage portion. The front passage portion in the first embodiment is a passage portion that combines the introduction passage portion 54A and the portion of the first bending passage portion 54B that exists on the upstream side of the first suppressing portion 61A. Further, the inner wall upper surface 54t in the first embodiment is formed as a planar portion. Further, the virtual vertical plane VL is a plane that exists substantially in parallel with the longitudinal direction B.

  In the first embodiment, the shape that protrudes in the front passage portion of the first suppressing portion 61A is air from the upper side 64c of the upstream opening end 64a of the gap 64 upward (in the direction indicated by the arrow of the coordinate axis X). An inclined inner wall surface 66a that is inclined to the downstream side in the flowing direction is formed. Specifically, the blocking member 65 constituting the first suppressing portion 61A is realized by applying a member formed such that the inner wall surface 65a on the upstream side in the air flow direction becomes the inclined inner wall surface 66a. doing. In addition, the surface part 65b which becomes the downstream of the flow direction of the air in the blocking member 65 is formed as a vertical inner wall surface substantially parallel to the virtual vertical surface VL.

  In addition, the inclined inner wall surface 66a in the first suppression portion 61A is connected to the upstream opening end 64a of the gap 64 at an acute angle α as shown in FIG. Further, the inclined inner wall surface 66a in the first embodiment is configured so that the entire surface up to the inner wall upper surface 54t of the passage space TS1 of the front passage portion is an inclined surface. The angle α is not particularly limited. For example, the angle α is set within a range greater than 0 ° and less than 90 ° so as to be an acute angle, and more preferably, the suppression effect of the first suppression unit 61A and the like. It is set to a small value as long as it is not impaired. In the first suppressing portion 61A, a part of the passage space TS1 exists only at the upper side 64c of the upstream opening end 64a of the gap 64, and the inner wall bottom surface 54e of the passage space TS1 is below the upstream opening end 64a. Are continuously present.

  The blocking member 65 constituting the first suppressing portion 61 </ b> A has an upper end of the upstream inner wall surface 65 a that is also the inclined inner wall surface 66 a (the intersecting position Pu) of the opening portion of the inlet 52 near the outlet 53. It arrange | positions so that it may exist in the position shifted | deviated by the required distance N in the downstream of the direction which flows the air of the 1st bending channel | path part 54B from 52a (FIG. 7).

  The gap 64 constituting the first suppressing portion 61A is such that the lower end portion 65c of the plate-shaped blocking member 65 is separated from the inner wall bottom surface 54e of the passage space TS1 of the front passage portion with a predetermined interval d1. By arranging it, it is set as the clearance gap which exists in the state which contact | connected the inner wall bottom face 54e of channel | path space TS1. In the gap 64, the path length M1 that is the dimension in the air flow direction is set to a required dimension in consideration of the relationship with the inclined inner wall surface 66a. The gap 64 is set to have the same width (length in the longitudinal direction B) as the width W (FIG. 5) of the passage space TS of the first bending passage portion 54B. Further, the gap 64 is installed such that a dimension J at which the upper side of the upstream opening end 64a is separated from the end 52a of the inlet 52 has a predetermined value. The dimension J at this time is set so that at least the upper end portion (Pu) of the blocking member 65 is smaller than the distance N displaced from the end portion 52a of the inlet 52 (J <N).

  The blocking member 65 may be obtained by integrally molding the same material as the air duct 51A or may be formed of a material different from the air duct 51A. Further, the blocking member 65 has an arrangement position (the above distance N), an interval d1, a path length M1 and a width W of the gap 64, and the wind velocity of the air flowing into the first bending path section 54B from the introduction path section 54A. Is selected and set from the viewpoint of equalizing as much as possible. These values are set in consideration of the size (capacity) of the air duct 51A and the flow rate (air volume) per unit time of the air that should flow through the air duct 51A or the charging device 4.

  Another restraining portion 62 of the air duct 51 </ b> A is provided as the most downstream restraining portion present at the outlet 53. In the first embodiment, the most downstream restraint portion 62 is formed by a breathable member 70 having a plurality of ventilation portions 71 to form a terminal end portion of the passage space of the second bending passage portion 54C (also an opening of the opening / exit 53). It is configured by closing it.

  As shown in FIG. 6, each of the plurality of ventilation portions 71 is a through-hole extending so that each opening shape is substantially circular and penetrates linearly. The plurality of ventilation portions 71 are arranged at equal intervals along the longitudinal direction B of the opening shape of the outlet 53, for example, and are arranged at equal intervals in the short direction C perpendicular to the longitudinal direction B. They are arranged so as to form (for example, 4 columns). Accordingly, the plurality of ventilation portions (holes) 71 are formed so as to be scattered almost uniformly throughout the entire area of the passage space TS at the end of the second bent passage portion 54C or the opening shape of the outlet 53. . For this reason, the air-permeable member 70 in Embodiment 1 is a perforated plate formed so that a plurality of ventilation portions (holes) 71 are dotted on a plate-like member.

  The breathable member 70 may be obtained by integrally molding the same material as the air duct 51A, or may be formed of a material different from the air duct 51A. The opening shape, opening size, hole length, and hole existence density of the ventilation portion (hole) 71 are selected and set from the viewpoint of making the air velocity of the air flowing out from the second bending passage portion 54C through the outlet 53 as uniform as possible. In addition, the size (capacity) of the air duct 51A and the flow rate per unit time of the air to be passed through the air duct 51A or the charging device 4 are set.

<Operation of blower>
Next, the operation of the air blower 5 (mainly due to the air duct 51A) will be described.

  In the blower device 5, when a drive setting time such as an image forming operation arrives, the blower 50 is first rotationally driven to send out a required amount of air. The air (E) sent from the started blower 50 is taken from the inlet 52 of the blower duct 51A through the connection duct 55 and then sent so as to flow into the passage space TS1 of the introduction passage portion 54A (FIG. 5). ).

  Subsequently, as shown in FIG. 5 and FIG. 7, the air (E) taken into the air duct 51A is sent to flow into the passage space TS1 of the first bent passage portion 54B through the passage space TS1 of the introduction passage portion 54A. (See arrows E1a, E1b, etc.). The air (E1) sent into the first bending passage portion 54B passes through the gap 64 of the first suppressing portion 61A and proceeds in a state where its traveling direction (air flowing direction) is changed to a substantially perpendicular direction. .

  At this time, the air (E2) when passing through the gap 64 of the first suppressing portion 61A has a relatively narrow gap 64 of the first suppressing portion 61A whose flow area is relatively smaller than the cross-sectional area of the passage space TS1 of the introduction passage portion 54A. Is suppressed (becomes in a state where the pressure has increased), and tries to flow out from the gap 64 in a uniform state. Moreover, the air (E2) when flowing into the passage space TS of the first bent passage portion 54B is in a direction in which the direction when flowing out from the gap 64 of the first suppressing portion 61A is substantially orthogonal to the longitudinal direction (B) of the outlet 53. Aligned.

  Subsequently, as shown in FIG. 7, the air (E2) flowing into the passage space TS of the second bent passage portion 54C first passes through the gap 64 of the first suppressing portion 61A, and the passage space of the second bent passage portion 54C. It becomes air (E2a) that travels almost straight into TS, but it flows into the passage space TS of the second bending passage portion 54C having a larger volume than the space of the gap 64 of the first restraining portion 61A, so that the second The air (E2b) travels so as to diffuse in a state of turning in the passage space TS of the bent passage portion 54C. As a result, the air (E2) at this time temporarily stays in a state of swirling in the passage space TS of the second bending passage portion 54C as a whole, so that unevenness in the wind speed is reduced.

  Finally, the air (E2) that has passed through the first restraining part 61A and flowed into the passage space TS of the second bending passage part 54C and temporarily retained is second bent as shown by an arrow E3 in FIG. The traveling direction is changed from the outlet 53 by passing through a plurality of ventilation portions (holes) 71 in the breathable member 70 constituting the most downstream suppressing portion 62 provided at the outlet 53 which is the terminal portion of the passage portion 54C. It is blown out in the state.

  At this time, the air (E3) blown out from the outlet 53 passes through the plurality of ventilation portions 71 in the breathable member 70 that is relatively narrower than the passage space TS of the second bending passage portion 54C and the opening area of the outlet 53. As a result, the flow is suppressed (the pressure is also increased at this time) and sent out.

  Thus, the air (E3) discharged from the outlet 53 of the blower duct 51A is discharged in a state where the wind speed is substantially uniform, particularly in the longitudinal direction B of the opening shape (elongated rectangle) of the outlet 53.

Here, the air duct 51 </ b> A in the first embodiment has a relationship in which the inlet 52 and the outlet 53 are formed in different opening shapes, and therefore the passage is connected to the passage portion 54 that connects the inlet 52 and the outlet 53. There is a portion where at least one of the cross-sectional shape (size) of the space TS and the direction in which the air flows is changed in the middle. In the present specification and the like, even when the inlet 52 and the outlet 53 have the same type of shape (for example, rectangles), when the opening areas are different from each other (for example, when they have similar shapes), Suppose that they are included in a relationship formed with different opening shapes.
In the air duct (51A) having such a portion that changes in the middle, generally, the air flow is disturbed such as separation or vortex in the portion where the cross-sectional shape or the direction in which the air flows is changed. It is known that even if air having a uniform wind speed is taken in, the air coming out from the outlet 53 tends to have non-uniform wind speed, particularly in the longitudinal direction B of the outlet 53.

Therefore, in order to solve such a problem, the present applicant has made a proposal regarding a blower device using a blower pipe provided with a plurality of suppression units as shown in Patent Document 1 described above. Also in the air duct 51A in the first embodiment, since the two suppressing portions 61 and 62 are provided, the unevenness of the wind speed in the longitudinal direction B of the air (E3) discharged from the outlet 53 is reduced as described above. become.
However, as a result of further research after that, in the air blowing device using the air blowing pipe proposed above, if the air volume to be blown on the target structure to be blown with air is relatively large, the air is discharged from the outlet 53 thereof. It has been newly found that the unevenness of the wind speed tends to increase in the longitudinal direction B of the air and the short direction C (FIG. 3, FIG. 5 etc.) orthogonal to the longitudinal direction B.

  On the other hand, in the air duct 51A in the first embodiment, the upper side 64c of the upstream opening end 64a of the gap 64 is the virtual vertical surface of the first suppression unit 61A that is one of the two suppression units 61 and 62. It is provided so as to have a shape that protrudes into the passage space TS1 in the front passage portion from the VL. In Embodiment 1, it is set as the shape which made the inclination inner wall surface 66a exist about the shape which protrudes and exists.

  Thereby, in this air duct 51A, as shown in FIG. 8, the air (E) taken in from the inlet 52 is introduced into the upstream portion of the introduction passage portion 54A and the first bending passage portion, which are particularly the front passage portions. When passing from the passage space TS1 toward the gap 64 of the first suppressing portion 61A and passing through the gap 64, a mainstream Em is generated that passes through the upstream opening end 64a of the gap 64. At the same time, the vortex flow Eu1 of the air that collides with the inclined inner wall surface 66a existing above the upstream opening end 64a of the gap 64 and moves in the direction opposite to the traveling direction of the main flow Em is above the main flow Em. Occurs on the side. For this reason, since the air (E) taken into this ventilation duct 51A receives the resistance by the said eddy current Eu1 from the upper side especially before approaching the clearance gap 64 of the 1st suppression part 61A, Loss will increase. Incidentally, although the illustration of the end portion 52a of the inlet 52 is omitted in FIG. 8 and the like, it actually exists in the passage space TS1 as shown in FIGS.

  As a result, the air (E2) flowing through the gap 64 of the first suppressing portion 61A and flowing into the remaining (downstream) passage space TS of the first bending passage portion 54B and the passage space TS of the second bending passage portion 54C, The suppression effect (pressure increase action) by the first suppression unit 61A is reliably received, and the wind speed unevenness is easily suppressed. And since the air (E2) at this time finally passes through the outlet 53 and is discharged as air (E3), it also receives the suppression effect by the second suppression portion 62, so the longitudinal direction B of the outlet 53 The wind speed unevenness at is further reduced.

Therefore, in this air duct 51A, even when a relatively large amount of air (E) is taken from the inlet 52, the vortex flow Eu is stronger when passing through the gap 64 of the first suppressing portion 61A. As a result, the pressure loss also increases, and as a result, the air (E3) finally discharged from the outlet 53 is suppressed from uneven wind speed in the longitudinal direction B of the outlet 53.
In this way, when the air volume of the air blown to the target portion of the charging device 4 (actually, the air taken in from the inlet of the blower duct) is increased, the pressure loss state in the blower duct 51A will be described later using the test results. .

  And the air (E3) discharged | emitted from the exit 53 of the ventilation duct 51A in this air blower 5 passes through the opening part 43 in the top plate 40a of the shield case 40 of the charging device 4, as shown in FIG. 40, the corona discharge wires 41A and 41B in the spaces (S1 and S2) divided by the partition wall 40d in the inner space S of the shield case 40 and the shield case 40 Sprayed onto the grid electrode 42 in the lower opening.

Since the air blown to the corona discharge wires 41A and 41B and the grid electrode 42 is discharged at a substantially uniform wind speed in the longitudinal direction B of the outlet 53 of the blower duct 51A, as described above, the air (E3) is discharged. The discharge wires 41 </ b> A and 41 </ b> B and the grid electrode 42 are also blown in a substantially equal state in the longitudinal direction B.
As a result, unnecessary substances such as paper dust, toner external additives, and discharge products that are to adhere to the two corona discharge wires 41A and 41B and the grid electrode 42 in the charging device 4 are made more uniform in air. Can be kept away by spraying.

As described above, in the charging device 4, finally, a deterioration phenomenon such as unevenness in discharge performance (charging performance) occurs due to unnecessarily adhering unnecessary materials to the corona discharge wires 41A and 41B and the grid electrode 42. This prevents the peripheral surface of the photosensitive drum 21 from being charged more uniformly (uniformly with respect to the rotation axis direction).
Further, the toner image formed by the image forming unit 20 provided with the charging device 4 and the image finally formed on the recording paper 9 have an image quality defect (density unevenness, etc.) due to charging failure such as uneven charging. Good image quality with reduced generation is obtained.

<Test>
FIG. 9 shows the results of a test for examining the performance characteristics of the blower 5 (pressure loss in the blower duct 51A).

In the test, air in which the average air volume of air discharged from the outlet 53 of the air duct 51A (Example 1) having the following configuration is about 0.35 m ³ / min (relatively large air volume) by the blower 50 is used. When introduced, the pressure of each air at the inlet 52 and outlet 53 of the air duct 51A is measured by simulation. The pressure at this time is measured at a plurality of locations in the longitudinal direction B of the inlet 52 and the outlet 53, and the average value thereof is used as the measurement result. Further, the pressure difference (corresponding to pressure loss) between the inlet 52 and the outlet 53 at this time was examined. These results are shown in FIG. 9 divided into a chart and a graph.

The entire shape of the air duct 51A of the first embodiment is as shown in FIGS. 3 to 6, and the inlet 52 has a rectangular opening shape of 22 mm long × 11 mm wide, and has an outlet. 53 was formed of an elongated rectangular opening shape of 350 mm (dimension in the longitudinal direction B) × 16 mm (dimension in the lateral direction C). The height of the passage space TS of the first bent passage portion 54B is 20 mm. The total volume of the passage space TS in all the passage portions 54 of the air duct 51A was 450 cm ³ .

The blocking member 65 of the first suppressing portion 61A is configured such that the entire inner wall surface 65a composed of the upstream plane is the inclined inner wall surface 66a. The inclined inner wall surface 66a is an inclined surface in which an angle α (FIG. 8) formed with the upstream opening end 64a of the gap 64 is 70 °. Further, the blocking member 65 is disposed at a position where the distance N from the end 52a of the inlet 52 at the upper end thereof is 5.5 mm. The gap 64 of the first suppressing portion 61A has a distance d1 of 1.5 mm, a path length M1 of 3.5 mm, a width W of 350 mm, and a distance J from the end portion 52a of the upper side 64c of the upstream opening end 64a of 2 mm. It was a gap. The thickness at the upper end of the blocking member 65 was 2 mm.
The most downstream restraining part 62 has a breathable member 70 provided with a plurality of ventilation parts 71 having a hole diameter of 1 mm and a length of 3 mm under the condition that the density is 0.42 pieces / mm ² (≈42 pieces / cm ² ). Thus, the outlet 53 is closed.

  For comparison, the same test was performed using an example of the air duct proposed in Patent Document 1 described above (the air duct 510 shown in FIG. 15). The results are also shown in FIG.

The air duct 510 of the comparative example is only the first restraining portion 61A in the air duct 51A of the first embodiment is changed to the first restraining portion 61 having the following configuration, and the air duct 51A of the first embodiment is otherwise used. It has the same configuration as
The first restraining part 61 in the air duct 510 separates the blocking member 65 in the first restraining part 61A from the lower end part 65c with a predetermined distance dx from the inner wall bottom surface 54e of the passage space TS of the first bending passage part 54B. The structure is arranged such that the gap 63 exists in the lower part. That is, the gap 63 is formed by an inclined inner wall surface 66a (actually an inner wall surface 65a on the upstream side of the blocking member 65) that forms a part of the passage space TS on the upper side 63a of the opening end that is on the upstream side in the air flow direction. And there is a plane substantially parallel to the virtual vertical plane VL), but an inner wall surface constituting a part of the passage space TS does not exist on the lower side 63b of the upstream opening end. The gap 63 has an interval dx of 1.5 mm, a path length Mx of 3.5 mm, and a distance N from the end 52a of the inlet 52 of the upstream opening end 63a to 2 mm. The thickness of the blocking member 65 is the same as the path length Mx of the gap 63.
Using the air duct 510, the above test was performed under the same conditions.

  For reference, the same test was performed using an example of the air duct proposed in Patent Document 1 described above (the air duct 511 shown in FIG. 16). The results are also shown in FIG.

The air duct 511 of the reference example is merely a change of the first restraining part 61 in the air duct 510 of the comparative example to the first restraining part 61x having the following configuration, and the rest is the same as the air duct 51A of the first embodiment. The same configuration is used.
The first suppression portion 61x in the air duct 511 forms a part of the passage space TS1 of the front passage portion on the upper side and the lower side of the upstream opening end 64a in the direction in which the air in the gap 64 flows, and the vertical direction (the virtual Inner wall surfaces 66b and 66c extending in a direction substantially parallel to the vertical plane VL are provided so as to be connected to each other. Accordingly, a part of the passage space TS exists separately on both the upper side 64c and the lower side 64d of the upstream opening end 64a of the gap 64 in the first suppressing portion 61x. Further, the inner wall surfaces 66b and 66c at this time are set to have substantially the same height dimension along the vertical direction. That is, the gap 64 in the first suppressing portion 61x is arranged so as to exist at a substantially central height position in the height direction of the passage space TS1. In addition, the inner wall surfaces 66b and 66c that exist on the upper and lower sides of the upstream opening end 64a of the gap 64 are configured using the upstream inner wall surface 65a of the flat plate-shaped blocking member 65.
The gap 64 has an interval dx of 1.5 mm, a path length Mx of 3.5 mm, and a distance N from the end 52a of the inlet 52 of the upstream opening end 64a of 2 mm. The thickness of the blocking member 65 is the same as the path length Mx of the gap 64.
The said test was done on the same conditions using this ventilation duct 511. FIG.

From the results shown in FIG. 9, in Example 1 using the air duct 51A, the pressure difference (pressure loss) between the inlet 52 and the outlet 53 is about 467 Pa, and the pressure difference in the comparative example using the air duct 510 is It turns out that it is increasing compared with about 341 Pa.
In Example 1 using the air duct 51A, the pressure difference (pressure loss) between the inlet 52 and the outlet 53 was smaller than the pressure difference of about 489 Pa in the reference example using the air duct 511. However, in Example 1 using the air duct 51A, it has been confirmed that a better result than the case of the reference example can be obtained with respect to the effect of suppressing the uneven wind speed of the air in the longitudinal direction of the outlet 53.

[Embodiment 2]
FIG. 10 shows an outline of the main part (mainly the air duct 51B) of the air blower 5 according to the second embodiment.

  The air duct 51B in the air blower 5 according to the second embodiment has an upstream opening end of the gap 64 on the upper side 64c of the upstream opening end 64a of the gap 64 instead of the first suppressing portion 61A in the first embodiment. 64a has the same configuration as the air duct 51A according to the first embodiment except that the first suppressing portion 61B is provided, which is provided with a projecting plate 67 in a state of extending and projecting into the passage space TS of the introduction passage portion 54A. is there.

The gap 64 of the first suppressing portion 61B in the air duct 51B constitutes the first suppressing portion 61B, similar to the gap 64 in the second embodiment and the gap 63 in the air duct 510 of the comparative example described above. By disposing the plate-shaped blocking member 65 so that the lower end portion 65c thereof is separated from the inner wall bottom surface 54e of the passage space TS of the first bent passage portion 54B by a predetermined distance d2, the passage space It was set as the clearance gap which exists in the state which contact | connected the inner wall bottom face 54e of TS. Surface 65 a of the upstream side of the blocking member 65 is configured as a virtual parallel to the vertical plane VL (vertical) plane from a position Pu of the crossing.

In addition, the protruding plate 67 in the first suppressing portion 61B is a passage of the front passage portion by a required protruding length L in a state parallel to the direction of the path length M2 of the gap 64 from the upper side 64c of the upstream opening end 64a of the gap 64. It is a flat plate member having a required thickness k protruding into the space TS1. Further, the protruding plate 67 is provided so as to exist in the entire region in the direction of the width W of the passage space TS. Further, the protruding plate 67 is arranged in a state of intersecting at a substantially right angle with the surface portion 65 a on the upstream side of the blocking member 65. The protrusion length L, thickness k, and the like related to the protrusion plate 67 are not particularly limited. For example, both the protrusion length L and the thickness k are less than the height d3 in the gap 64. Is preferably set to a value of. At this time, in the first suppressing portion 61B, a part of the passage space TS1 exists only above the upper side 64c of the upstream opening end 64a in the gap 64. The final path length of the gap 64 is a value (M2 + L) obtained by adding the protrusion length L of the protrusion plate 67 to the thickness (M3) of the blocking member 65.

  And the air blower 5 using this air duct 51B operate | moves substantially similarly to the case of the air blower which concerns on Embodiment 1. FIG.

Further, particularly in the air duct 51B, as illustrated in FIG. 11, the air (E) taken in from the inlet 52 is particularly directed from the passage space TS1 of the front passage portion toward the gap 64 of the first suppression portion 61B. When advancing and passing through the gap 64, a mainstream Em is generated that passes through the upstream opening end 64a of the gap 64, whereas the protruding plate 67 that exists above the upstream opening end 64a of the gap 64 is generated. One vortex flow Eu2 of the air rotating so as to collide and move in the direction opposite to the traveling direction of the main flow Em is generated. The vortex flow Eu2 at this time protrudes from the upstream opening end 64a of the gap 64 and collides with a projecting plate 67 that exists on the opposite side of the gap 64 and intersects the traveling direction of the main flow Em at a further acute angle. Proceed to go backwards. For this reason, the resistance force due to the retrograde vortex flow Eu2 intersecting at such an acute angle is larger (compared to the vortex flow Eu1 generated in the blower duct 51A in the first embodiment and the vortex flow Eux generated in the blower duct 510 of the comparative example). Become.
As a result, the air (E) taken into the air duct 51B receives a strong resistance due to the eddy current Eu2 especially before entering the gap 64 of the first suppressing portion 61B, and is thus discharged from the outlet 53. The pressure loss up to this will increase.

  As a result, in the air duct 51B, air that flows through the gap 64 of the first suppressing portion 61B and flows into the remaining (downstream) passage space TS of the first bent passage portion 54B and the passage space TS of the second bent passage portion 54C. (E2) reliably receives the suppressing effect (pressure increasing action) by the first suppressing portion 61B, and the wind speed unevenness is further easily suppressed. And since the air (E2) at this time finally passes through the outlet 53 and is discharged as air (E3), it also receives the suppression effect by the second suppression part 62, so the longitudinal direction of the outlet 53 The uneven wind speed in B is further reduced.

  Next, the test (Example 2) which investigates the performance characteristic (pressure loss in the ventilation duct 51B) of the air blower 5 which concerns on this Embodiment 2 was done. The results are also shown in FIG.

The test was performed under the same conditions as the test in the first embodiment. The air duct 51B used in the test was set to the same conditions as the air duct 51A used in the test of Embodiment 1 except that the following conditions were different.
That is, in this air duct 51B, with respect to the gap 64 of the first suppressing portion 61B, the distance d3 is 1.5 mm, the path length (M3 + L) is 5.5 mm, the width W is 350 mm, and the inlet at the upper side 64c of the upstream opening end 64a. The gap J is set so that the distance J deviated from the end 52a of the 52 is substantially zero, and the lower part thereof is in contact with the inner wall bottom surface 54e of the passage space TS of the first bending passage portion 54B. The blocking member 65 of the first suppressing portion 61B has the upstream surface portion 65b disposed at a position where the distance N deviated from the end portion 52a of the inlet 52 is 2 mm. The protruding plate 67 is a flat plate having a thickness k of 1 mm in a state where the protruding length L protruding from the upstream surface portion 65b (virtual vertical surface VL) of the blocking member 65 is 2.5 mm.

  From the results shown in FIG. 9, in Example 2 using the air duct 51 </ b> B, the pressure difference (pressure loss) between the inlet 52 and the outlet 53 is increased as compared with the comparative example using the air duct 510. I understand that. Moreover, in Example 2, it can be seen that the pressure difference is larger than in Example 1 and the reference example.

[Other embodiments]
The air duct 51 used in the air blower 5 is not limited to the air ducts 51A and 51B employing the first air suppressors 61A and 61B exemplified in the first and second embodiments, and the first air suppressor having other configurations. You may apply the ventilation pipe which employ | adopted 61. FIG. A configuration example of another air duct that employs the first suppression unit 61 having another configuration will be exemplified below.

  The air duct 51C illustrated in FIG. 12 employs a first suppression unit 61C that is a combination of the configuration of the first suppression unit 61A in the first embodiment and the configuration of the first suppression unit 61B in the second embodiment. is there. In other words, the first suppressing portion 61C has a shape that protrudes into the passage space of the front passage portion of the first suppressing portion 61C and extends from the lower end of the inclined inner wall surface 66b into the passage space TS1 of the front passage portion. A protruding plate 67 that protrudes is provided.

A blower duct 51D illustrated in FIG. 13A applies a blocking member 65 provided with a gap 64 having a required interval d3 at a substantially central height position in the height direction (the direction indicated by the arrow of the coordinate axis Y). The shape projecting into the passage space TS1 of the front passage portion of the air duct 51D is formed on the upper side 64c and the lower side 64d of the upstream opening end 64a of the gap 64 in the blocking member 65 in the first embodiment of the first embodiment. The first control unit 61D is configured by including inclined inner wall surfaces 66c and 66d that are common to the inclined inner wall surface 66a of the suppressing unit 61A. Here, the inclined inner wall surface 66d is a virtual vertical surface perpendicular to the inner wall bottom surface 54e at a position Pu2 where the inner wall bottom surface 54e constituting the passage space TS1 in the front passage portion and the inner wall surface 65a on the upstream side of the blocking member 65 intersect. is formed as the inner wall surfaces constituting the shape exists inclined so as to protrude into the V L by remote passage space TS1.

The blower duct 51E illustrated in FIG. 13B applies the blocking member 65 provided with the gap 64 illustrated in FIG. 13A and protrudes into the passage space TS1 of the front passage portion of the blower duct 51E. In the blocking member 65, the upper plate 64c and the lower side 64d of the upstream opening end 64a of the gap 64 are respectively provided with protruding plates 67 that are the same as the protruding plate 67 of the first suppressing portion 61B in the second embodiment. It has the 1st control part 61E formed . In the air duct 51E, the inner wall surface 65a on the upstream side of the blocking member 65 is formed as a plane substantially parallel to the virtual vertical plane VL at each of the intersecting positions Pu1 and Pu2.

  The air duct 51F illustrated in FIG. 13C is implemented at the lower end or the upper end of the inclined inner wall surfaces 66e, 66f common to the inclined inner wall surfaces 66c, 66d in the first suppressing portion 61D illustrated in FIG. The protrusion plate 67 which is common with the protrusion plate 67 of the 1st suppression part 61B in the form 2 of this is each provided and comprised.

  FIG. 14 shows the main part of the operating state of the blower 5 using the blower duct 51D illustrated in FIG. 13A only by the shape of the passage portion.

That is, when this air duct 51D is used, as shown in FIG. 14, the air (E) taken in from the inlet 52 is upstream of the introduction passage portion 54A and the first bending passage portion, which are particularly the front passage portions. When passing through the gap 64 from the side portion passage space TS1 toward the gap 64 of the first suppressing portion 61D, a main flow Em is generated that passes through the upstream opening end 64a of the gap 64. The air swirls Eu3 and Eu4 rotating so as to collide with the inclined inner wall surfaces 66c and 66d existing above and below the upstream opening end 64a of the gap 64 and move in the direction opposite to the traveling direction of the main flow Em are It occurs on both sides. Therefore, the air (E) taken into the air duct 51D is in a state in which the resistance due to the two eddy currents Eu3 and Eu4 is in contact from both above and below, particularly before entering the gap 64 of the first suppressing portion 61E. Therefore, the pressure loss is further increased.
The effect of increasing the pressure loss at this time is, for example, also in the air duct 511 (FIG. 16) of the reference example described above, a vertical surface above and below the upstream opening end 64a of the gap 64 in the first suppressing portion 61x. As a result of the test of the reference example shown in FIG. 9, two comparative vortices similar to the two eddy currents Eu3 and Eu4 are generated. As a result, the pressure difference (pressure loss) is increased as compared with the above, so it is considered that the effect can be inferred from the test result of this reference example.

  As a result, the air (E2) flowing through the gap 64 of the first suppressing portion 61D and flowing into the remaining (downstream) passage space TS of the first bending passage portion 54B and the passage space TS of the second bending passage portion 54C, The suppression effect (pressure increase effect) by the first suppression unit 61D is reliably received, and the wind speed unevenness is easily suppressed. And since the air (E2) at this time finally passes through the outlet 53 and is discharged as air (E3), it also receives the suppression effect by the second suppression portion 62, so the longitudinal direction B of the outlet 53 The wind speed unevenness at is further reduced.

  Therefore, in the air duct 51D, even when a relatively large amount of air (E) is taken from the inlet 52, the two eddy currents Eu3, 3 when passing through the gap 64 of the first suppressing portion 61D. Eu4 is also generated more strongly and the pressure loss also increases. As a result, the air (E3) finally discharged from the outlet 53 is further suppressed in the unevenness of the wind speed in the longitudinal direction B of the outlet 53. It will be.

Incidentally, in the case of using the air duct 51E illustrated in FIG. 13B and the air duct 51F illustrated in FIG. 13C, the two vortex flows Eu3 described above are the same as in the case of using the air duct 51D. , Eu4 are generated in substantially the same manner, so that the pressure loss of each air (E) taken into the air ducts 51E, 51F is further increased.
Moreover, about the height position of the clearance gap 64 in 1st suppression part 61D-61F of each ventilation duct 51D-51F illustrated in FIG.13 (a)-(c), it is in the up-down direction from the center position in the height direction. It is also possible to set the position at the deviation height. Furthermore, the angle α1 of the inclined inner wall surfaces 66c and 66e and the angle α2 of the inclined inner wall surfaces 66d and 66f in the first suppressing portions 61D and 61F of the air ducts 51D and 51F illustrated in FIGS. They are set to the same value, but can be set to different values.

  In the first and second embodiments, the air duct 51 is formed with the passage space TS being bent twice (the passage portion having the first bent passage portion 54B and the second bent passage portion 54C). However, even if the air duct 51 includes a passage portion 54 formed in a state where the passage space TS is bent once, the passage space is further reduced. A blower pipe provided with a passage portion 54 formed in a state where TS is bent three times or more may be used. For example, the blower pipe including the passage portion 54 formed in a state where the passage space TS is bent once is a side surface (for example, the first bent passage in FIG. 4) that proceeds from the first bending passage portion 54B as it is in the horizontal direction. A blower tube having a structure in which an outlet 53 is provided on a side surface portion on the right side of the portion 54B.

  Moreover, in Embodiment 1, 2, although the case where the two suppression parts 61 and 62 were provided as a several suppression part in the ventilation duct 51 of the air blower 5 was shown, you may provide three or more. Further, the restraining portions other than the most downstream restraining portion 62 provided at the outlet 53 are a portion where the cross-sectional shape is changed in the passage space TS of the passage portion 54 of the air duct 51 and a direction in which air flows in the passage space TS. It is preferable to be provided at a site after (for example, immediately after) is changed.

  The most downstream restraint portion 62 provided at the outlet 53 is not limited to the case of the air-permeable member 70 exemplified in the first embodiment, and the other restraint portion 62 is applied to, for example, a filter. It may be configured using a breathable member 70 typified by a porous member such as a non-woven fabric (one in which the plurality of ventilation portions 71 are irregularly shaped through gaps). In addition, when the nonuniformity of the wind speed in the longitudinal direction B of the exit 53 can be suppressed, you may leave the structure which made the exit 53 completely open without arrange | positioning the suppression part 62 in the exit 53.

  Further, the charging device 4 to which the blower device 5 is applied may be a charging device of a type in which the grid electrode 42 is not installed, that is, a so-called corotron type charging device. Further, the charging device 4 may be one that uses one or three or more corona discharge wires 41. In addition, as a long target structure to which the blower 5 is applied, a corona discharger for discharging the photosensitive drum 21 or the like, or a corona discharger for charging or discharging a charged body other than the photosensitive drum may be used. In addition, it may be a long structure that requires air blowing other than the corona discharger.

  In addition, the configuration of the image forming method and the like is not particularly limited as long as the image forming apparatus 1 is equipped with a long target structure to which the blower 5 needs to be applied. For example, in the first embodiment, the image forming apparatus 1 is exemplified to form a single color image using one image forming unit 20, but the image forming apparatus forms an image of a different color. The image forming apparatus may form a multicolor image using a plurality of image forming units 20. If necessary, the image forming apparatus may be an image forming apparatus that forms an image made of a material other than the developer.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 4 ... Charging apparatus (target structure)
5 ... Blower 50 ... Blower 51 ... Blower duct (Blower pipe)
52 ... Inlet 53 ... Outlet 54 ... Passage 54A ... Introduction passage (front passage)
54B ... 1st bending channel | path part 54e ... Inner wall bottom face 54t ... Inner wall upper surface 61 ... Suppression part 61A-61F ... 1st suppression part 62 ... The most downstream suppression part 64 ... Gap 64a ... Open end 64c on the upstream side of a gap ... Upper side 65 of upstream opening end: blocking member (shielding part)
65a ... Upstream inner wall surface 66a-66f ... Inclined inner wall surface 67 ... Projection plate 70 ... Breathable member 71 ... Ventilation part B ... Longitudinal direction C ... Short direction E ... Air (flow)
TS ... Passage space Pu ... Intersecting position VL ... Virtual vertical plane

Claims (7)

An inlet for taking in air;
It is arranged in a state facing a long longitudinal part in one direction of the target structure to which air taken in from the inlet is blown, and extends along the longitudinal part of the target structure and has an opening shape different from that of the inlet. An exit,
A passage portion formed in a state where a passage space for flowing air by connecting between the inlet and the outlet is bent at least once in the middle;
A plurality of suppressing portions that are provided in different portions in the direction of flowing air in the passage space of the passage portion, and suppress the flow of air;
With
The passage portion has a first bent passage portion that is bent at a position closest to the inlet, and a front passage portion that exists immediately before an upstream side in the direction of flowing air of the first bent passage portion,
One of the plurality of restraining portions is a first restraining portion having a structure in which a gap extending in the transverse direction is cut off across a part of the passage space in the first bending passage portion and extends.
In the first suppression part, at least the upper side of the upstream opening end in the direction of flowing the air in the gap constitutes an inner wall upper surface constituting the passage space in the front passage part and the blocking part of the first suppression part. It is provided to have a shape that protrudes into the passage space of the front passage portion from a virtual vertical plane orthogonal to the upper surface of the inner wall at a position where the inner wall surface on the upstream side intersects ,
The shape of the first restraining portion that protrudes into the front passage portion has an inclined inner wall surface that is inclined over the entire surface on the downstream side in the air flow direction as it moves upward from at least the upper opening end of the gap. The air duct that is configured . An inlet for taking in air;
It is arranged in a state facing a long longitudinal part in one direction of the target structure to which air taken in from the inlet is blown, and extends along the longitudinal part of the target structure and has an opening shape different from that of the inlet. An exit,
A passage portion formed in a state where a passage space for flowing air by connecting between the inlet and the outlet is bent at least once in the middle;
A plurality of suppressing portions that are provided in different portions in the direction of flowing air in the passage space of the passage portion and suppress the flow of air;
With
The passage portion has a first bent passage portion that is bent at a position closest to the inlet, and a front passage portion that exists immediately before an upstream side in the direction of flowing air of the first bent passage portion,
One of the plurality of restraining portions is a first restraining portion having a structure in which a gap extending in the transverse direction is cut off across a part of the passage space in the first bending passage portion and extends.
In the first suppression part, at least the upper side of the upstream opening end in the direction of flowing the air in the gap constitutes an inner wall upper surface constituting the passage space in the front passage part and the blocking part of the first suppression part. It is provided to have a shape that protrudes into the passage space of the front passage portion from a virtual vertical plane orthogonal to the upper surface of the inner wall at a position where the inner wall surface on the upstream side intersects,
The shape of the first restraining portion that protrudes into the passage space extends beyond the virtual vertical surface into the front passage portion and protrudes in a state parallel to the direction of the path length of the gap. A blower pipe configured by providing a plate . The shape of the first restraining portion that protrudes into the passage space is formed by providing a protruding plate that extends from the lower end of the inclined inner wall surface and protrudes into the front passage portion, and the protruding plate is The blower pipe according to claim 1, wherein the blower pipe is provided in a state parallel to a direction of a path length of the gap in the first suppressing portion . The shape of the present projects into the passage space of the first reduction unit, the gap in the direction of the upstream-side opening end of the upper and lower claims 1 to 3 are configured to exist in both the flowing air The blast tube of any one of these . The shape of the first restraining portion that protrudes into the passage space and exists on both the upper side and the lower side is in a state of being symmetrical with respect to the gap at the same position in the air flow direction of the passage space. blowing tube according to claim 4, which is configured to.   The air blower provided with the air blower which sends air, and the air blow pipe of any one of Claim 1 thru | or 5 which takes in the air sent from the said air blower. A target structure having a longitudinal portion that is long in one direction to be blown with air;
A blower that blows air on a longitudinal portion of the target structure, and
An image forming apparatus, wherein the blower is configured by the blower according to claim 6.

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