JP2015169799A - Air duct, air-blasting system, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air duct or the like including a passage part which connects an inlet to take in an air and an outlet having an opening shape different from the inlet facing a portion in a length direction of an object structure blown with the air, and a plurality of suppression parts disposed at a different region one another in a direction of air flow in the passage part and suppressing an air flow, and capable of suppressing wind-speed unevenness among a plurality of regions in a short side direction orthogonal to a length side direction of an outlet even when the volume of an air flow is increased.SOLUTION: An air duct is disposed at a first region between an inlet and an outlet as a plurality of suppression parts, and includes: a first suppression part allowing a long gap along a length direction to exist; a second suppression part disposed at a second region at the downstream in the flowing direction of the first suppression part and allowing the long gap along the length direction at least in the center of the short side direction of the second region to exist; and a third suppression part disposed at a third region at the downstream in the flowing direction of the second suppression part and allowing a plurality of ventilation parts along the length direction at a plurality of positions shifted from the center of the short-side direction of the third region to exist as the outlet.

Description

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

In recent years, the present applicant has proposed a blower and an image forming apparatus using the blower shown below (Patent Document 1).
In other words, the blower is arranged in a state facing a blower for sending air, an inlet for taking in air sent from the blower, and a longitudinal portion of a long target structure to which the air taken in from the inlet should be blown. And an outlet for allowing the air to flow along a direction perpendicular to the longitudinal direction, and a main body formed with a passage space for flowing the air between the inlet and the outlet. Is formed in a long opening shape parallel to the longitudinal portion of the target structure, and the air inlet pipe and the outlet are formed in different opening shapes, and the main body portion of the air blowing pipe A plurality of suppression portions that are provided at different portions in the direction of flowing air in the passage space and that suppress the flow of air, and are provided at a lowermost portion of the suppression portion in the direction of flowing air of the passage space. Suppressing portion of, a plurality of vent passageways space is formed so that a state closes breathable member dotted at the site of the most downstream. Examples of the target structure include a corona discharger.

JP 2013-88731 A

  The present invention 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 is long in one direction parallel to the longitudinal part of the target structure. And an outlet having a different opening shape from that of the inlet, a passage portion in which a passage space for flowing air is formed by connecting between the inlet and the outlet, and air provided in different portions in the direction of the passage of air in the passage space of the passage portion. As a blast tube provided with a plurality of restraining parts that restrain the flow of air, the short direction perpendicular to the longitudinal direction of the outlet, even when the amount of air taken in from the inlet and discharged from the outlet is increased A blower pipe capable of suppressing the unevenness of the wind speed between the plurality of parts is provided, and a blower device and an image forming apparatus using the blower pipe are provided.

The blast tube of this invention (A1)
An inlet for taking in air;
It is arranged in a state facing a longitudinal portion of a long target structure to which air taken in from the inlet is blown, and has a long opening shape parallel to the longitudinal portion of the target structure and the inlet. Outlets with different opening shapes;
A passage portion in which a passage space for flowing air is formed by connecting between the inlet and the outlet;
A plurality of restraining portions that are provided at different portions in the direction of flowing air in the passage space of the passage portion, each of which has a shape extending in parallel with the longitudinal direction of the opening shape of the outlet, and suppresses the flow of air. Prepared,
As the plurality of suppression units,
A first suppression unit that is provided in a first portion between the inlet and the outlet of the passage unit and suppresses the flow of air by causing a long gap along the longitudinal direction;
A length along the longitudinal direction at least in the center of the short side direction perpendicular to the longitudinal direction of the second part is provided in the second part of the passage part downstream of the first restraining part in the flowing direction. A second suppression unit that suppresses the flow of air by causing a small gap;
Of the passage portion, provided at a third portion downstream of the second restraining portion in the flowing direction, parallel to the longitudinal direction at a plurality of positions shifted from the center of the short direction of the third portion. A third restraining portion for restraining the flow of air by causing a plurality of extending ventilation portions to exist as the outlet;
It is provided with at least.

The blast tube of this invention (A2) is the blast tube of the above invention A1, wherein the passage portion is bent at at least one place,
The first portion is present in the upstream in the flow direction than the most downstream bent portion that is bent toward the outlet of the passage portion and located in the most downstream in the flow direction,
The second part and the third part are present downstream in the direction from the most downstream bent portion.

  In the blast tube of the present invention (A3), in the blast tube of the above invention A1 or A2, the plurality of ventilation portions of the third suppression portion are two ventilation portions having the same distance from the gap of the second suppression portion. It is provided.

  The blast tube of this invention (A4) is the blast tube of any of the above inventions A1 to A3, wherein the plurality of ventilation portions of the third suppression portion are at both ends in the longitudinal direction at the central portion in the short direction. It has the part extended toward.

  The blast tube of this invention (A5) is a corona discharger having a linear discharge member in which the object structure is laid along the longitudinal direction in the blast tube of any of the inventions A1 to A4, A plurality of positions shifted from the center in the short direction of the third suppressing portion are positions corresponding to portions shifted from positions facing the discharge members of the corona discharger.

  Moreover, the air blower of this invention (B1) is provided with the air blower which sends air, and the air blow pipe in any one of said invention A1 to A5, and the air sent from the said air blower from each opening part of the inlet_port | entrance of the said air blow pipe Each of them is characterized by incorporating.

  The air blower of this invention (B2) is a corona discharger which has the linear discharge member by which the said target structure was constructed along the longitudinal direction in the air blower of the said invention B1, Said 3rd suppression part A plurality of positions shifted from the center in the short direction are positions corresponding to portions shifted from positions facing the discharge members of the corona discharger.

  The image forming apparatus according to the present invention (C1) further includes a long target structure to be blown with air and a blower for blowing air toward a longitudinal portion of the target structure. The apparatus is composed of the blower of the invention B1.

  The image forming apparatus of the present invention (C2) is the corona discharger according to the image forming apparatus of the above invention C1, wherein the target structure has a linear discharge member erected along the longitudinal direction. A plurality of positions shifted from the center in the short direction of the suppressing portion are positions corresponding to portions shifted from positions facing the discharge members of the corona discharger.

  According to the blast pipe of the invention A1, even when the air volume of air taken in from the inlet and discharged from the outlet is increased, between the plurality of portions in the short direction perpendicular to the longitudinal direction of the outlet. The uneven wind speed can be suppressed.

In the blast tube of the invention A2, the effect of the invention A1 can be obtained even when the passage portion has a bent portion bent halfway as compared with the case where the structure of the invention is not provided.
In the blast tube of the invention A3, the effect of the invention A1 can be reliably obtained as compared to the case where a plurality of ventilation portions having different distances from the gap of the second suppression portion are provided.

In the blast tube of the invention A4, compared to the case where the plurality of ventilation portions do not have the portions extending toward the central portion in the short direction at both ends in the longitudinal direction, from the both ends in the longitudinal direction of the opening shape of the outlet. The air can be discharged.
In the blast tube of the invention A5, vibration of the discharge member of the corona discharger due to the air discharged from the outlet can be suppressed.

According to the blower of the above invention B1, even when the air volume of the air taken in from the inlet of the blower pipe and discharged from the outlet is increased, a plurality in the short direction perpendicular to the longitudinal direction of the outlet of the blower pipe The air can be blown onto the target structure in a state in which the unevenness of the wind speed between the parts is suppressed.
In the air blower of the said invention B2, it can suppress that the discharge member of a corona discharger vibrates with the air discharged | emitted from the exit of an air blower compared with the case where it does not have the structure of the invention.

According to the image forming apparatus of the invention C1, even when the air volume of the air taken in from the inlet of the blower pipe and discharged from the outlet in the blower is increased, the short direction orthogonal to the longitudinal direction of the outlet of the blower pipe is used. Air can be blown onto the target structure in a state where uneven wind speed between a plurality of parts in the hand direction is suppressed.
In the image forming apparatus according to the invention C2, it is possible to suppress the discharge member of the corona discharger from vibrating due to the air discharged from the outlet of the blower tube, as compared with the case where the configuration of the invention is not provided.

It is the schematic which shows the outline | summary of the ventilation duct which concerns on Embodiment 1 etc., the ventilation apparatus using the same, and an image forming apparatus. FIG. 2 is a schematic perspective view illustrating a charging device including a corona discharger provided in the image forming apparatus of FIG. 1. It is a schematic perspective view which shows the outline | summary of the ventilation duct applied to the charging device of FIG. It is sectional drawing which follows the QQ line of the air blower (air blow duct) of FIG. It is the schematic which shows a state when the air blower (mainly air duct) of FIG. 3 is seen from upper direction. It is the schematic which shows a state when the exit part in the ventilation duct of FIG. 4 is seen from the downward direction. It is explanatory drawing shown in the state when the operation state etc. of the air blower of FIG. 3 are seen from upper direction. It is explanatory drawing shown in the state when the operation state etc. of the air blower of FIG. 3 are seen in the cross section which follows the QQ line of FIG. (A) is explanatory drawing which shows some schematic structures (a passage space, a clearance gap, a ventilation part, etc.) of the ventilation duct used by the test, (b) is the wind speed distribution in the transversal direction of the ventilation duct of (a). It is a graph which shows the simulation result of. (A) is explanatory drawing which shows some schematic structures (a passage space, a clearance gap, a ventilation part, etc.) of the ventilation duct of the 2nd example used by the test, (b) is the ventilation of the 2nd example of (a). It is a graph which shows the simulation result of the wind speed distribution in the transversal direction of a duct. (A) is explanatory drawing which shows some schematic structures (a passage space, a clearance gap, a ventilation part, etc.) of the ventilation duct of the 3rd example used by the test, (b) is the ventilation of the 3rd example of (a). It is a graph which shows the simulation result of the wind speed distribution in the transversal direction of a duct. (A) is explanatory drawing which shows one part schematic structure (passage space, a clearance gap, a ventilation part, etc.) of the ventilation duct of the 4th example used by the test, (b) is ventilation of the 4th example of (a). It is a graph which shows the simulation result of the wind speed distribution in the transversal direction of a duct. It is the schematic shown in the state when another structural example of the ventilation part of the 3rd suppression part in a ventilation duct is seen from the downward direction. It is the schematic shown in the state when another structural example of the ventilation part of the 3rd suppression part in a ventilation duct is seen from the downward direction. It is a schematic explanatory drawing shown in the state when the various form examples of a ventilation duct are seen from upper direction. (A) is explanatory drawing which shows the one part schematic structure (a passage space, a clearance gap, a ventilation part, etc.) of the ventilation duct used by the test for reference purposes, (b) is the ventilation duct of the structure of (a). It is a graph which shows the simulation result of the wind speed distribution in a transversal direction.

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

[Embodiment 1]
1 to 6 show a blower tube according to Embodiment 1, a blower device using the blower tube, and an image forming apparatus. FIG. 1 shows an outline of the image forming apparatus, and FIG. 2 shows a charging device that is used in the image forming apparatus and is an example of a long target structure to which air should be abutted by the blower tube or blower. 3 shows the outline of the blower pipe or blower, FIG. 4 shows the state of the cross section along the line Q-Q in the blower (blower pipe) of FIG. 3, and FIG. 5 shows the blower of FIG. FIG. 6 shows a state when the blower of FIG. 3 is viewed from below (exit). The arrows indicated by reference signs X, Y, and Z in the drawings are orthogonal coordinate axes (directions) indicating the respective directions of the width, height, and depth of the three-dimensional space assumed in each drawing.

<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. An image forming unit 20 for transferring to the recording paper 9 as an example, a paper feeding device 30 for receiving, supplying and supplying the recording paper 9 supplied to the image forming unit 20, and a toner image formed by the image forming unit 20 Is fixed to the recording paper 9.

  The image forming unit 20 is configured using, for example, a known electrophotographic system, and includes a photosensitive drum 21 that rotates in a direction indicated by an arrow A (a clockwise direction in the drawing), and a photosensitive member. A charging device 4 that charges a peripheral surface, which is an image forming area of the drum 21, to a required potential, and light (dotted line with an arrow) based on image information (signal) input from the outside to the surface of the photosensitive drum 21 after charging. , An exposure device 23 that forms an electrostatic latent image having a potential difference, a developing device 24 that develops the electrostatic latent image into a toner image with toner, and a transfer device 25 that transfers the toner image onto a sheet 9. The cleaning device 26 mainly removes toner remaining on the surface of the photosensitive drum 21 after transfer.

  Of these, a corona discharger is used as the charging device 4. 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 has an external shape having a rectangular top plate 40a partially opened and side plates 40b and 40c hanging downward from a long side portion extending along the longitudinal direction B of the top plate 40a. A shield case (cover member) 40, 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 two end support members, respectively. The two corona discharge wires 41A and 41B installed in a state of being stretched almost linearly through the inner space of the shield case 40 and the lower opening of the shield case 40 are covered with the lower opening. A grid-like grid electrode (electric field adjustment plate) 42 attached in a state of being present between the corona discharge wire 41 and the peripheral surface of the photosensitive drum 21 is provided. Reference numeral 40d shown in FIG. 4 and the like is a partition plate that partitions a space in which the two corona discharge wires 41A and 41B are arranged.

  Further, the charging device 4 is in a state in which the corona discharge wire 41 (41A, 41B) faces the circumferential 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 be present at least in the image formation target area along the direction. The charging device 4 is configured to apply a charging voltage to the discharge wire 41 (between the photosensitive drum 21) from a power supply device (not shown) when an image is formed.

  Further, when the charging device 4 is used, substances (unnecessary materials) such as paper dust of the paper 9, discharge products generated by corona discharge, and external additives of toner adhere to the corona discharge wires 41 and the grid electrodes 42. As a result of the contamination, corona discharge is not sufficiently or uniformly performed, and charging defects such as uneven charging may occur. For this reason, the charging device 4 is provided with a blower device 5 for abutting air toward the discharge wire 41 and the grid electrode 42 in order to prevent or suppress unwanted substances from adhering to the discharge wire 41 and the grid electrode 42. ing. Further, an opening 43 for taking in air sent from the blower 5 is formed on the upper surface 40 a of the shield case 40 of the charging device 4. 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 tray type, cassette type, etc. paper container 31 that accommodates a plurality of recording sheets 9 of a required size and type used for image formation in a stacked state, and the paper container. 31 is provided to send out the recording paper 9 accommodated in the paper 31 one by one toward the conveyance path, and the recording paper 9 is sent out one by one when the paper feeding time comes. A plurality of paper containers 31 are provided according to the usage mode. A one-dot chain line with an arrow in FIG. 1 indicates a conveyance path through which the recording paper 9 is mainly conveyed. The recording paper conveyance path is composed of 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 rotating in contact with a required pressure so as to substantially follow the axial direction of the heating rotator 37 are provided. The fixing device 35 performs fixing by introducing and passing the recording paper 9 after the toner image is transferred to a fixing processing unit formed between the heating rotator 37 and the pressure rotator 38. .

  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 an example.

  In the image forming apparatus 1, when the control device or the like 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 charged to a predetermined polarity and potential by the charging device 4. The At this time, the charging device 4 generates a corona discharge in a state where a charging voltage is applied to the corona discharge wire 41 and an electric field is formed between the discharge wire 41 and the peripheral surface of the photosensitive drum 21. 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, exposure based on image information is performed from the exposure device 23 on the peripheral surface of the charged photosensitive drum 21 to form an electrostatic latent image having a required potential difference. Thereafter, when the electrostatic latent image formed on the photosensitive drum 21 passes through the developing device 24, it is developed with toner charged to a required polarity supplied from the developing roll 24a in the developing device 24. It is visualized as a toner image.

  Next, when the toner image formed on the photoconductive drum 21 is conveyed to the transfer position facing the transfer device 25 by the rotation of the photoconductive drum 21, it is supplied from the paper supply device 30 through the conveyance path at this timing. The recording sheet 9 is transferred by the transfer action of the transfer device 25. The peripheral surface of each 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 pressed with the heating rotator 37 in the fixing device 35. Heat and pressure are applied when passing through the fixing processing section between the rotating body 38 and the rotating body 38. As a result, the toner image is melted and fixed on the recording paper 9. 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.

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

  As shown in FIGS. 1 and 3, the blower 5 includes a blower 50 having a rotating fan that sends air, and a blower duct that takes in the air sent from the blower 50 and guides it to the charging device 4 to be blown and discharges it. 51.

  The blower 50 is driven and controlled so as to send a required amount of air. As such a blower 50, for example, a radiant flow type blower fan is used. On the other hand, as shown in FIGS. 3 to 6, the air duct 51 includes an inlet 52 for taking in air sent from the blower 50 and a longitudinal direction B of the long charging device 4 to which air taken in from the inlet 52 should be blown. , An outlet 53 that is disposed substantially facing the portion (for example, the opening 43 of the upper surface 40a of the shield case 40) 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 has a passage portion (main body portion) 54 in which a passage space 54a for flowing air between the passages 53 is formed.

  The passage portion 54 of the blower duct 51 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) B. And a rectangular tube-shaped passage portion formed so as to extend linearly. The first bent passage portion 54B is substantially horizontal (substantially parallel to the direction indicated by the coordinate axis X) so that the width of the passage space is expanded from a portion (on the way) near the other end of the introduction passage portion 54A to enlarge the passage cross-sectional area. A bending passage portion having a rectangular tube shape formed so as to be bent and extend substantially at right angles to the longitudinal direction of the outlet 53 in the direction in which the outlet 53 is formed. 54 C of 2nd bending channel | path parts are bent and charged in the perpendicular direction (direction substantially parallel to the direction shown by the coordinate axis Y) toward the downward direction from the one end part of the 1st bending channel | path part 54B with the width | variety of the channel | path space being the same state. It is a bent passage portion formed so as to extend closer to the device 4. An outlet 53 having a configuration to be described later is formed at the end of the second bending passage portion 54C. Further, the passage spaces 54a of the first bending passage portion 54B and the second bending passage portion 54C are both set to have substantially the same width (dimension in the longitudinal direction B).

  The inlet 52 of the air duct 51 is formed so that the opening shape is substantially square (FIG. 3). A connection duct 55 is connected to the inlet 52 to connect the blower 50 and send air from the blower 50 to the inlet 52 of the blower duct 51 (FIGS. 3 and 5). On the other hand, the outlet 53 of the air duct 51 is formed so that its opening shape is a long opening shape (for example, a rectangle) parallel to the longitudinal direction B portion (opening portion 43) of the charging device 4. For this reason, the air duct 51 has a relationship in which the inlet 52 and the outlet 53 are formed in different opening shapes. However, even when the inlet 52 and the outlet 53 have the same shape, when the opening areas are formed so as to be different from each other (when they are similar shapes), they are included in the relationship formed with different opening shapes. Further, as shown in FIG. 5 and the like, the inlet 52 is in a state of projecting by a required dimension G outside the one end 53a in the longitudinal direction (B) of the outlet 53 having a rectangular opening shape. Is formed.

  Here, in the air duct 51 having the inlet 52 and the outlet 53 having different opening shapes, there is a portion in which the cross-sectional shape of the passage space 54 a is changed in the middle of the passage portion 54 connecting the inlet 52 and the outlet 53. Will do. Incidentally, in the air duct 51 according to the first embodiment, the opening shape of the inlet 52 is a square, whereas the opening shape of the outlet 53 is a rectangle. For this reason, the air duct 51 has a bent portion (actually the first bent passage portion 54B) of the passage portion 54 (passage space 54a thereof), and the sectional shape of the passage space 54a in the introduction passage portion 54A. Is substantially square, but the cross-sectional shape of the passage space 54a in the first bending passage portion 54B is changed to a rectangle that expands only in the horizontal direction (the height does not change). In other words, the cross-sectional shape of the passage space 54a of the introduction passage portion 54A is the cross-sectional shape of the passage space 54ab that suddenly widens substantially horizontally in the first bending passage portion 54B.

  However, in the blower duct 51 having such a portion where the cross-sectional shape of the passage space 54a changes, the air flow is disturbed such as separation or vortex in the portion where the cross-sectional shape changes. For this reason. In the air duct 51 having such a configuration, even if air having a uniform wind speed is taken in from the inlet 52, the wind speed of the air coming out from the outlet 53 tends to be uneven (uneven state).

  Thus, the tendency that the air speed of the air exiting from the outlet 53 is finally non-uniform is that the direction in which the air flows (progresses) in the air duct 51 changes regardless of the change in the cross-sectional shape of the passage space 54a. In other words, the same occurs when the passage space 54a is bent in the middle. Furthermore, the tendency of the air velocity of the air exiting from the outlet to be ultimately non-uniform occurs more prominently when the cross-sectional shape of the passage space 54a changes and the direction in which the air flows (travel) changes.

  15a to 15d show typical examples 510A to 510C of the air ducts in which the inlet 52 and the outlet 53 are formed in different opening shapes. In FIG. 15A, air taken into the inlet 52 in each duct 510 is shown. Each state of the wind speed and the wind speed of the air exiting from the outlet 53 is indicated by the length of the arrow. In FIG. 15, each air duct 510 is shown as viewed from the upper surface side. In the figure, when the lengths of the arrows are the same, the wind speed is the same, and when the lengths are different, the wind speed is different. Furthermore, the dotted line in a figure has shown the passage space (side wall part which forms) of each duct. Incidentally, the air ducts 510B and 510C are also structural examples in which the direction in which the air flows is changed in the middle and at least one of the cross-sectional shape and the cross-sectional area of the passage space is changed. In addition, the air duct 510D shown in FIG. 15d is a configuration example in which the inlet 52 and the outlet 53 are formed in the same opening shape (and the same opening area), and only the direction in which the air flows is changed in the middle. It is a duct.

  For this reason, the present applicant, as described in Patent Document 1 described above, a blower pipe provided with a plurality of suppressing portions that suppress the flow of air at different portions in the flow direction of the passage space in the blower pipe. Has proposed. According to the proposed blow pipe, it is possible to suppress the unevenness of the wind speed in the longitudinal direction of the outlet and the unevenness of the wind speed in the short direction perpendicular to the longitudinal direction of the air discharged from the outlet.

By the way, in the proposed blast pipe, for example, when the air volume of air taken in from the inlet and discharged from the outlet is increased (for example, when the air volume introduced from the inlet is 0.35 m ³ / min or more), the outlet Although it is possible to suppress uneven wind speed in the longitudinal direction of the outlet of the air discharged from the air, it may not be possible to suppress uneven wind speed in the short direction perpendicular to the longitudinal direction.

  Therefore, in the blower duct 51 of the blower 5, as shown in FIGS. 3, 4, etc., there is at least one passage space 54 a that connects the inlet 52 and the outlet 53 and flows air (in this example, two places). ) On the premise that the air duct is provided with the passage portion 54 bent in the above-described manner, the air flow is directed to different parts in the direction of flowing the air in the passage space 54a of the passage portion 54 (direction indicated by the arrow R). A configuration in which three suppression units 61, 62, 63 described later are provided as a plurality of suppression units for suppression is employed.

  The three suppression units 61, 62, and 63 are the following first suppression unit 61, second suppression unit 62, and third suppression unit 63. The first suppressing portion 61 is provided in a first portion between the inlet 52 and the outlet 53 in the passage portion 54 and has a shape extending in parallel with the longitudinal direction B of the opening shape of the outlet 53. It is a suppression unit that suppresses the flow of air by providing a gap 65 disposed at a position shifted from the center in the short direction C (the thickness direction of the passage space 54a of the first part) perpendicular to the longitudinal direction B. The second suppressing portion 62 is provided in the second portion downstream of the passage portion 54 in the flow direction R from the first suppressing portion 61, and has a shape extending in parallel with the longitudinal direction B of the opening shape of the outlet 53. It is a suppression part which suppresses the flow of air by making the clearance gap 67 arrange | positioned in the center position of the said transversal direction C (thickness direction of the passage space 54a of a 2nd site | part) in a 2nd site | part. The third suppression portion 63 is provided in the third portion of the passage portion 54 in the direction (R) in which air flows more than the second suppression portion 62, and the short direction C in the third portion (the passage of the third portion). A plurality of ventilation portions 71 and 72 existing in parallel with the longitudinal direction B of the opening shape of the outlet 53 at a plurality of positions shifted from the center in the thickness direction of the space 54a as the outlet 53, thereby suppressing the flow of air. It is. The plurality of positions shifted from the center in the short direction C of the third suppressing portion 63 are set to positions corresponding to a plurality of portions selected in the short direction C orthogonal to the longitudinal direction B of the charging device 4. ing.

  Further, the air duct 51 is configured such that the passage portion 54 has the introduction passage portion 54A, the first bending passage portion 54B, and the second bending passage portion 54C as described above, in other words, bent at two places. The passage part is adopted. That is, the passage portion 54 has an outlet between the upstream bending portion bent between the introduction passage portion 54A and the first bending passage portion 54B, and between the first bending passage portion 54B and the second bending passage portion 54C. 53 and the most downstream bent portion bent toward 53. In the first embodiment, the first portion is set to a portion (actually in the first bent passage portion 54B) that exists upstream in the direction R in which air flows than the most downstream bent portion of the passage portion 54. ing. In addition, both the second part and the third part are located in a part (actually in the second bent passage part 54C) that exists downstream in the direction R in which air flows than the most downstream bent part of the passage part 54. It is set. As a result, the first suppressing portion 61 is provided at the site of the first bent passage portion 54B, and the second suppressing portion 62 and the third suppressing portion 63 are provided at the location of the second bent passage portion 54C. It has become.

  The first suppressing portion 61 does not change the outer shape of the first bent passage portion 54B, and a plate-shaped blocking member 64 is provided in the passage space 54a of the bent passage portion 54B, and the bottom surface portion in the cross-sectional shape of the passage space 54a. On the other hand, it arrange | positions in the state which opens a clearance gap (65) and crosses.

  Specifically, as shown in FIG. 4 and the like, the blocking member 64 is in a state of crossing the upper part (downstream side in the direction indicated by the coordinate axis Y) of the cross-sectional shape in the passage space 54a of the first bending passage portion 54B. Further, the lower end portion 64a of the blocking member is disposed in a state where a predetermined interval d1 is provided with respect to the bottom surface portion 54b having a cross-sectional shape of the passage space 54a. Thereby, the 1st suppression part 61 consists of the elongate substantially rectangular shape extended in parallel with the cross direction D (the longitudinal direction B of the exit 53. FIG. 5) below the interruption | blocking member 64 of the channel | path space 54a. The gap 65 is present. The gap 65 in the first suppressing portion 61 may be disposed at a position shifted from the center in the thickness direction of the passage space 54a of the first bending passage portion 54B (substantially the same as the direction indicated by the coordinate axis Y in this example). In form 1, it arrange | positions in the position used as the lowest end of the passage space 54a of the channel | path part 54B. Here, the thickness direction in the passage space 54a of each passage portion 54 refers to a direction orthogonal to the longitudinal direction B of the outlet 53 and the direction R of flowing air (the same applies thereafter). ). The position shifted from the center in the thickness direction of the passage space 54a where the gap 65 is disposed is a position when the center of the thickness dimension of the passage space 54a does not exist in the gap d1 of the gap 65. .

  As shown in FIGS. 4, 5, and the like, the blocking member 64 in the first embodiment is a virtual connection between both end portions 65 a and 65 b in the transverse direction D of the gap 65 formed by the blocking member 64 of the first suppressing portion 61. The straight line (two-dot chain line) VL is downstream in the direction R2 (direction indicated by the coordinate axis X) in which the air flows in the first bent passage portion 54B from the inner end portion 52a closer to the first bent passage portion 54B in the inlet 52. It exists so that it may exist in the position (1st site | part) of the side. At this time, the blocking member 64 has an upstream end portion (substantially the same portion as the virtual straight line VL) required on the downstream side in the direction R2 in which the air in the first bent passage portion 54B flows from the inner end portion 52a of the inlet 52. It is arranged so as to exist at a position shifted by a distance N.

  Further, the position (the distance N shifted to the downstream side of the air flow direction R2) where the blocking member 64 constituting the first suppressing portion 61 is arranged, the distance d1, the path length M and the width (the longitudinal direction of the gap 65). The length (W) is selected and set from the viewpoint of making the air velocity of the air flowing from the introduction passage portion 54A into the first bending passage portion 54B as uniform as possible. These values are set in consideration of the dimensions (capacity) of the duct 51 and the flow rate (air volume) per unit time of the air that should flow through the duct 51 or the charging device 4.

  The second suppressing portion 62 does not change the outer shape of the second bent passage portion 54C, and the plate-like blocking member 66 is inserted into the passage space 54a of the bent passage portion 54C, and the thickness direction of the passage space 54a (coordinate axis X It is comprised by arrange | positioning in the state which opens and leaves the clearance gap (67) in the center of (direction shown by).

  Specifically, as shown in FIG. 4 and the like, the blocking member 66 blocks the side surface portion of the cross-sectional shape in the passage space 54ac of the second bent passage portion 54C, and the width ( It is arranged in a state in which a gap 67 in a state where a required interval d2 is opened exists in the center of a portion along a direction intersecting the longitudinal direction B of the outlet. As a result, the second suppressing portion 62 extends in the center of the blocking member 66 of the passage space 54ac of the second bending passage portion 54C in parallel with the transverse direction D (substantially the same as the longitudinal direction B of the outlet 53). The gap 67 has a substantially rectangular shape. The gap 67 in the second suppressing portion 62 is disposed at the center position in the thickness direction of the passage space 54ac of the second bending passage portion 54C (substantially the same as the direction indicated by the coordinate axis X in this example). The center position in the thickness direction of the passage space 54a where the gap 65 is disposed refers to a position when the center of the gap d1 of the gap 65 is substantially coincident with the center of the thickness dimension of the passage space 54ac. Furthermore, the 2nd suppression part 62 is arrange | positioned in the site | part (2nd site | part) upstream of the direction R3 which flows air among the channel | path spaces 54a of 54 C of 2nd bending channel | path parts.

  With respect to the gap d2, the path length M2, and the width (length in the longitudinal direction) W of the gap 67 in the blocking member 66 that constitutes the second suppressing part 62, it flows into the second bent path part 54C from the first bent path part 54B. It is selected and set from the viewpoint of making the wind speed in the longitudinal direction B of air as uniform as possible. These values are set in consideration of the dimensions (capacity) of the duct 51 and the flow rate per unit time of the air that should flow through the duct 51 or the charging device 4 as in the case of the first suppressing unit 61. The

  The third suppression portion 63 does not change the outer shape of the second bending passage portion 54C, and the passage space of the bending passage portion 54C that is the most downstream portion (third portion: end portion) in the direction R2 in which air flows. A plate-shaped blocking member 68 is traversed in 54a with two ventilation portions 71 and 72 present at two positions shifted from the center of the passage space 54a in the thickness direction (in this example, substantially the same as the direction indicated by the coordinate axis X). It is comprised by arranging in the state to do.

  Specifically, as shown in FIG. 4 and the like, the blocking member 68 blocks the side surface portion of the cross-sectional shape in the passage space 54a of the second bending passage portion 54C, and also cuts the width ( In the vicinity of both ends of a portion along the direction crossing the longitudinal direction B of the outlet, gaps 71 and 72 are provided as the outlet 53 in a state where necessary intervals d3 and d4 are respectively opened. Thereby, the 3rd suppression part 63 is parallel to the transversal direction D (it is substantially the same as the longitudinal direction B of the exit 53) in two parts of the interruption | blocking member 66 of the channel | path space 54a of the 2nd bending channel | path part 54C. It has a structure in which two ventilation portions 71 and 72 having an elongated and substantially rectangular shape exist. The ventilation portions 71 and 72 in the third suppressing portion 63 are positions shifted from the center in the thickness direction of the passage space 54a of the second bending passage portion 54C and are short-side directions C orthogonal to the longitudinal direction B of the charging device 4. Are arranged at positions corresponding to the two parts 45 and 46 selected in FIG. As shown in FIG. 4 and the like, the positions of the two limited portions 45 and 46 of the charging device 4 are the openings 43 facing the two discharge wires 41A and 41B installed in the longitudinal direction B of the shield case 40. This is a portion deviated from the positions 43c and 43d.

  The positions 43c and 43d facing the discharge wires 41A and 41B are the shortest distances from the discharge wires 41A and 41B in the opening 43. Further, the positions shifted from the positions 43c and 43d facing the discharge wires 41A and 41B are such that the air discharged from the gaps 71 and 72 serving as the outlet 53 directly hits the discharge wires 41A and 41B. The position is away from the wire 41 in a parallel state. The positions shifted from the positions 43c and 43d facing the discharge wires 41A and 41B in the first embodiment are limited to positions close to the inner wall surfaces of the side plates 40b and 40c which are both ends in the short direction C of the shield case 40, respectively. ing.

  Further, as shown in FIGS. 4, 6, etc., the ventilation portions 71, 72 in the first embodiment penetrate through a substantially rectangular shape extending in parallel to the transverse direction D (longitudinal direction B) of the blocking member 68. It is comprised by the hole (through-hole: clearance gap). The ventilation portions 71 and 72 are present at positions shifted with respect to the gap 67 in the second suppressing portion 62 when viewed in the direction R3 in which air flows (in other words, positions that do not overlap). In the first embodiment, as shown in FIGS. 4 and 6, the ventilation portions 71 and 72 are set so that the distances from the gap 67 in the second suppression portion 62 are equal to each other. Incidentally, although the intervals d3 and d4 of the ventilation portions 71 and 72 are set to the same value, for example, if effective for uniforming the wind speed of the air discharged from the ventilation portions 71 and 72, different values are set. You can set it.

  Regarding the distances d3, d4, the path length M3 and the width (length in the longitudinal direction) W of the ventilation portions 71, 72 in the blocking member 68 constituting the third suppressing portion 63, the air discharged from the ventilation portions 71, 72 Is selected and set from the viewpoint of making the wind speed in the longitudinal direction B and the short direction C uniform as much as possible. These values are set in consideration of the dimensions (capacity) of the duct 51 and the flow rate per unit time of the air that should flow through the duct 51 or the charging device 4 as in the case of the first suppressing unit 61. The

  Hereinafter, the operation of the blower 5 will be described.

  In the blower device 5, when the drive setting time such as during the image forming operation is reached, the blower 50 is first rotationally driven to send out a required amount of air. As shown in FIG. 7, the air (E) sent from the started blower 50 is taken into the passage space 54 a from the inlet 52 of the blower duct 51 through the connection duct 55.

  As shown in FIG. 7, the air (E) taken in from the inlet 52 of the air duct 51 advances so as to flow substantially along the flow direction R1 in the passage space of the introduction passage portion 54A (E1). From the middle and finally from the introduction passage portion 54A, the flow is changed in the direction so as to move to the passage space 54a of the first bending passage portion 54B extending at a right angle in a substantially horizontal direction (E1a, E1b).

  Subsequently, as shown in FIG. 8, the air (E1a, E1b) flowing so as to move to the first bending passage portion 54B blocks the first suppression portion 61 present at the upstream end of the first bending passage portion 54B. While being blocked by the member 64, it finally flows through the gap 65 of the suppressing portion 61.

  At this time, the air (E2) that flows through the gap 65 of the first suppressing portion 61 and flows into the passage space 54a of the first bending passage portion 54B is in a state where the flow is suppressed by the suppressing portion 61 (the pressure increases). And passes through the gap 65. Further, the direction of the air (E2) at this time when flowing out from the gap 65 of the first suppressing portion 61 is the direction R2 in which the air flows in the passage space 54a of the first bending passage portion 54B (this direction R2 is the outlet 53). It is also a direction substantially perpendicular to the longitudinal direction B.).

  Subsequently, the air (E2) that has passed through the gap 65 of the first suppressing portion 61 and has flowed into the passage space 54a of the first bent passage portion 54B is almost directed toward the outlet 53 below the first bent passage portion 54B. It moves to the passage space 54ab of the second bending passage portion 54C that continuously extends in a state bent in a right-angle direction (a space portion located on the upstream side in the air flow direction from the second suppression portion 62).

  As shown in FIG. 8, the air (E2) flowing into the passage space 54a of the second bending passage portion 54C has a volume larger than that of the passage space 54a of the introduction passage portion 54A and the space of the gap 65 of the first suppression portion 61. By flowing in a state (E2a, E2b) that is diffused into the passage space 54ab of the wide second bending passage portion 54C, it stays in the passage space 54ab of the second bending passage portion 54C so as to circulate temporarily. In particular, uneven wind speed in the longitudinal direction B is reduced.

  Next, the air (E2) flowing into the passage space 54ac of the second bent passage portion 54C flows and advances in a state substantially along the direction R3 in which air flows in the passage space 54ac, and is approximately at the center of the second bent passage portion 54C. While being blocked by the blocking member 66 of the second suppressing portion 62 existing in the portion, it finally flows through the gap 67 of the suppressing portion 62.

  At this time, the passage space 54ac passes through the gap 67 of the second suppression portion 62 and is downstream of the second bending passage portion 54C (a space portion located downstream of the second suppression portion 62 in the direction of air flow). The air (E <b> 3) when flowing in is in a state where the flow is suppressed by the suppressing unit 62 (a state where the pressure is increased), and passes through the gap 67. Further, the air (E3) flowing out through the gap 67 of the second suppressing portion 62 has a traveling direction substantially in the direction R3 in which the air in the passage space 54ac on the downstream side of the second bent passage portion 54C should flow. While being sent out in a uniform manner, the wind speed in the longitudinal direction B corresponding to the transverse direction D of the gap 67 is almost uniform and sent out.

  Further, as shown in FIG. 8, the air (E3) flowing out through the gap 67 of the second suppressing portion 62 has a passage space 54ac of the second bending passage portion 54C having a larger volume than the space of the gap 67. In the state of being diffused again, and flows so as to abut against a part of the blocking member 68 of the third suppressing portion 63 facing the gap 67 (a region extending in the longitudinal direction B in the central portion in the lateral direction C). (E3a, E3b). As a result, the air (E3) stays in the passage space 54ac downstream of the second bending passage portion 54C so as to circulate temporarily (causes a vortex), and in addition to the uneven wind speed in the longitudinal direction B, Unevenness of the wind speed in the short direction C is reduced.

  Finally, as shown in FIG. 8, the air (E3) flowing into the passage space 54ac on the downstream side of the second bent passage portion 54C is a third suppressing portion 63 provided at the end portion of the bent passage portion 54C. Are blown out as air (E4a, E4b) distributed from two ventilation portions 71, 72 (two outlets 53A, 53B) that also serve as the outlet 53.

  At this time, the air (E4a, E4b) blown from the outlets 53A and 53B is a relatively narrow ventilation portion than the original opening area of the outlet 53 (the cross-sectional area of the passage space 54a of the second bent passage portion 54C). The flow is suppressed by passing through 71 and 72 (the pressure is also increased at this time) and is sent out. Further, the air (E4a, E4b) blown out from the outlets 53A, 53B is sent out in such a manner that its traveling direction is substantially aligned again in the direction R3 in which the air should flow in the passage space 54ac on the downstream side of the second bending passage portion 54C. At the same time, the wind speeds in the longitudinal direction B corresponding to the transverse direction D of the ventilation portions 71 and 72 are also substantially aligned. Furthermore, the air (E4a, E4b) blown out from the outlets 53A, 53B is reduced in the unevenness of the wind speed in the short direction C in the passage space 54ac on the downstream side of the second bent passage portion 54C as described above. The wind speeds between the outlets 53A and 53B are almost aligned with each other.

  As described above, the air (E4a, E4b) distributed and discharged from the outlets 53A, 53B configured by the two ventilation portions 71, 72 in the third suppression portion 63 of the blower duct 51 is as shown in FIG. The charging device 4 is discharged so as to flow toward the two portions 45 and 46 selected in the short direction C perpendicular to the longitudinal direction B of the charging device 4. At this time, the air (E4a, E4b) has the same wind speed in the longitudinal direction B of the outlets 53A, 53B as described above to suppress unevenness of the wind speed, and the wind speed between the outlets 53A, 53B is also substantially the same. They are aligned and the uneven wind speed is suppressed.

  The air (E4a, E4b) discharged from the outlets 53A, 53B of the blower duct 51 in the blower device 5 passes through the openings 43 in the upper surface 40a of the shield case 40 of the charging device 4, and the partition plate 40d of the shield case 40 is used. Are blown so as to flow toward two portions 45 and 46 which are limited in the short direction C in the internal spaces (S1 and S2) divided by.

  At this time, the air (E4a, E4b) is two in the shield case 40 in a state where the wind speed unevenness in the longitudinal direction B of the outlets 53A, 53B and the wind speed unevenness between the outlets 53A, 53B are suppressed as described above. The discharge wires 41A and 41B are blown so as to pass through the portions of the opening 43 facing the discharge wires 41A and 41B that are displaced from the positions 43c and 43d. For this reason, the two corona discharge wires in the internal spaces S1 and S2 of the shield case 40 It flows so as to pass between the discharge wires 41A, 41B and the side plates 40b, 40c of the shield case 40 without directly hitting the terminals 41A, 41B. And after this air (E4a, E4b) finally passes through the opening of the grid electrode 42 or passes through the gap between the lower ends of the side plates 40b, 40c of the shield case 40 and the grid electrode 42, Finally, it moves so as to be discharged out of the shield case 40.

  As a result, the air (E4a, E4b) finally discharged from the air duct 51 passes along the outer sides of the two corona discharge wires 41A, 41B in the internal space (S1, S2) of the shield case 40. Since it moves so as to pass in a state in which the wind speed unevenness is suppressed and is discharged to the outside of the shield case 40, the discharge product (ozone or the like) that tries to adhere to the grid electrode 42 at the beginning of the two discharge wires 41A and 41B ), And unnecessary materials such as paper powder and toner external additives can be kept away from each other and discharged to the outside of the shield case 40. Further, since the air (E4a, E4b) discharged from the blower duct 51 is not directly and strongly blown onto the two corona discharge wires 41A, 41B, the corona discharge wires 41A, 41B are vibrated unnecessarily. I will not let you. Such an air duct 51 only requires the provision of the three restraining parts 61 to 63 having a simple structure, and therefore has the advantage that it can be provided at a low price without causing a significant increase in manufacturing cost. For example, there is an advantage that there is no possibility of increasing the pressure loss in the air blowing because it is only necessary to pass the air taken in from 52 through the three suppressing portions 61 to 63 and discharge the air.

  Therefore, since the charging device 4 is equipped with the blower device 5, unnecessary materials are loosely attached to the discharge wires 41 </ b> A and 41 </ b> B and the grid electrode 42 and the discharge wires 41 </ b> A and 41 </ b> B vibrate. As a result, the charging performance is prevented from being totally or partially deteriorated, and the peripheral surface of the photosensitive drum 21 can be more uniformly charged. Further, the toner image formed by the image forming unit 20 provided with the charging device 4 and the image finally formed on the paper 9 are image quality defects (density) due to charging defects such as uneven charging and deterioration of charging performance. A good image in which the occurrence of unevenness or the like is suppressed is obtained.

  FIG. 9 shows test conditions and results for examining the performance characteristics of the blower 5 (the wind speed distribution of the air discharged from the blower duct 51).

In the test, when a relatively large amount of air having an average air volume of 0.33 m ³ / min is introduced from the blower 50 by simulation, the outlets 53A and 53B (third suppression) of the air duct 51A shown in FIG. This was done by examining the wind speed of air exhausted from the vent portions 71 and 72 of the section 63 (averaged wind speed in the entire longitudinal direction B of each outlet).

  The entire shape of the air duct 51A is as shown in FIG. 3 to FIG. 6, the inlet 52 has a substantially square opening shape of 25 mm × 25 mm, and the outlet 53 has a size of 2 mm × 250 mm. What was comprised by two opening part 53A, 53B which consists of an elongate rectangular opening shape was used. The air duct 51A has a dimension in the thickness direction of the passage space 54ab of the first bent passage portion 54A (in the direction along the coordinate axis Y in this example) of about 30 mm, and the passage space 54ac of the second bent passage portion 54C. The dimension in the thickness direction at (in this example, the direction along the coordinate axis X) is about 30 mm.

  Further, the air duct 51A has a position where the distance N shifted from the one end 52a of the entrance of the passage space 54ab to the downstream side is about 2 mm with respect to the first suppressing portion 61 provided in the passage space 54ab of the first bending passage portion 54A (first position). A substantially flat partition member 64 is arranged at one part) so that a gap 65 having a height d1 of 1.5 mm, a path length M1 of 8 mm, and a width W of 250 mm exists at the lower end of the passage space 54ab. Configured. Further, with respect to the second suppressing portion 62 provided in the passage space 54ac on the upstream side of the second bent passage portion 54C, a position where the distance shifted from the bottom surface portion 54b of the passage space 54ab to the downstream side in the direction R3 of flowing air is about 4 mm. A substantially flat partition member 64 in which a gap 67 having a height d2 of about 4 mm, a path length M2 of about 2 mm, and a width W of 250 mm is present at the central portion in the thickness direction of the passage space 54ab is provided in the (second portion). Configured by placing. Further, the third suppression portion 63 provided in the passage space 54ac on the downstream side of the second passage portion 62 has a height d3, at a position (third portion) where the distance from the second suppression portion 62 is about 10 mm. Positions where the two ventilation portions 71 and 72 having d4 of about 2 mm, a path length M3 of about 2 mm, and a width W of 250 mm are close to both ends in the thickness direction of the passage space 54ac (about 3 mm from each end to the inside) A substantially flat partition member 68 present at a shifted position) is arranged.

  The result of this test is shown in FIG. The position in the short direction shown on the horizontal axis in the figure is the distance from the inner surface of one side plate 40b (the side plate existing upstream in the rotation direction A of the photosensitive drum 21) in the shield case 40 of the charging device 4. It is. In addition, the wind speed indicated on the vertical axis in the figure is calculated as the wind speed at a height corresponding to the height position of the two discharge wires 41A, 41. As the charging device 4, two discharge wires 41A and 41 are arranged at positions of about 7.5 mm and about 17.5 mm at the position in the short direction of the horizontal axis in FIG. It is assumed that 40d is also arranged at a position of about 12.5 mm in the lateral direction of the horizontal axis.

From the result shown in FIG. 9B, in this blower duct 51 </ b> A, even when the air volume of air taken in from the inlet 52 and discharged from the outlet 53 is increased, it is orthogonal to the longitudinal direction B of the charging device 4. It can be seen that uneven wind speed is suppressed between the two outlets 53A and 53B distributed in the short direction C. It can also be seen that the air (E4a, E4b) discharged from the two outlets 53A, 53B is in a very weak state with a wind speed of 0.1 m ³ / min with respect to the position where the discharge wires 41A, 41B are present. Incidentally, according to the present inventors, the wind speed in the longitudinal direction B of the outlets 53A and 53B of the air duct 51A at this time is about 0.5 to 1.5 m / second which is the average wind speed of the target value over the entire longitudinal direction. It is a value close to seconds, and it has been confirmed that uneven wind speed in the longitudinal direction B is also suppressed.

  Further, in this test, the wind speed distribution when the air duct 51B shown in FIG. When the air duct 51B is compared with the air duct 51A (FIG. 9a), the distance between the second restraining portion 62 and the third restraining portion 63 in the passage space 54ac on the downstream side of the second bending passage portion 54C (flows air). The only difference is that the length along the direction R3 is shortened from about 10 mm to about 6 mm, and the other conditions are the same.

  The test results at this time are shown in FIG. From the result shown in FIG. 10B, in the air duct 51B, the air discharged from the outlets 53A and 53B is further applied to the inner wall surfaces of the side surface portions 40b and 40c in the longitudinal direction of the shield case 40 of the charging device 4. It can be seen that it flows along (approaching) and at almost the same wind speed.

  Further, in this test, the wind speed distribution when the air duct 51C shown in FIG. The air duct 51C, when compared with the air duct 51B (FIG. 10a), deletes both end portions in the thickness direction of the passage space 54ac on the downstream side of the second bent passage portion 54C to a position reaching the ventilation portions 71 and 72. The only difference is the difference between the two, and the other conditions are the same.

  The test result at this time is shown in FIG. From the result shown in FIG. 11B, in the air duct 51C, the air discharged from the outlets 53A and 53B runs along the inner wall surfaces of the side surface portions 40b and 40c in the longitudinal direction of the shield case 40 of the charging device 4. It can be seen that it will flow.

  Further, in this test, the wind speed distribution when the air duct 51D shown in FIG. When the air duct 51C is compared with the air duct 51B (FIG. 10a), the positions where the two ventilation portions 71 and 72 in the third suppressing portion 63 are brought close to the partition plate 40d of the charging device 4 (the partition plate 40d and each The only difference is that it is arranged at a position substantially in the middle of the discharge wires 41A and 41B), and the other conditions are the same.

  The test results at this time are shown in FIG. From the result shown in FIG. 12B, in this air duct 51D, the air discharged from the outlets 53A and 53B is along (approaching) the partition plate 40d in the shield case 40 of the charging device 4 and substantially the same wind speed. You can see that it starts flowing.

For reference, the wind speed distribution when a relatively small amount of air with an average air volume of 0.25 m ³ / min is introduced from the blower 50 is similarly examined assuming the air duct 51E shown in FIG. It was. The air duct 51E is a partition plate of the charging device 4 in the air duct 51A shown in FIG. 9A, like the air duct D shown in FIG. The only difference is that it is arranged at a position close to 40d (a position approximately in the middle between the partition plate 40d and each of the discharge wires 41A and 41B), and the other conditions are the same as the air duct 51A. is there.

  The test results at this time are shown in FIG. From the result shown in FIG. 16 (b), in the air duct 51E, the air discharged from the outlets 53A and 53B is discharged into the two discharge wires 41A and 41A of the charging device 4 in a relationship in which a relatively small amount of air is introduced. It can be seen that the flow directly toward 41B increases.

[Other embodiments]
Although the ventilation ducts 71 and 72 in the 3rd suppression part 63 illustrated the thing of the structure which penetrated and opened as a whole as the ventilation duct 51, about the ventilation part in the 3rd suppression part 63, besides this, Any structure having air permeability can be applied without particular limitation, and the structure exemplified below may be used.
That is, as the ventilation portions 71 and 72 in the third suppression portion 63, for example, as shown in a partially enlarged view in FIG. Or a porous member such as a nonwoven fabric that is applied to a filter or the like in a region closed by a breathable member 75 (a plurality of ventilation portions are scattered in irregular shapes and states) The thing of the structure block | closed with the air permeable member represented by the thing which is represented) is mentioned.

Moreover, although the ventilation parts 71 and 72 in the 3rd suppression part 63 illustrated what was formed in the elongate rectangular opening shape extended in parallel with the longitudinal direction B of the opening shape of the exit 53 as the ventilation duct 51, The ventilation portion in the third suppression portion 63 is not particularly limited as long as it is a configuration that can suppress the wind speed unevenness, and can be applied, and has the configuration exemplified below. May be.
That is, as the ventilation portions 71 and 72 in the third suppression portion 63, for example, as shown in FIG. 14, at both ends in the longitudinal direction B of the ventilation portions 71 and 72 having the elongated rectangular opening shape, the short direction It is possible to apply an opening shape in which end ventilation portions 73 (a, b) and 74 (a, b) having a shape extending halfway toward the center of C are added.
In the air duct 51 adopting the third suppressing portion 63 including the ventilation portions 71 and 72 having the end ventilation portions 73 and 74 added as described above, the ventilation portions 71 and 72 having the elongated rectangular opening shape are described above. In addition to the discharge of air (E4a, E4b), the passage on the downstream side of the second bent passage portion 54C from the expanded end ventilation portions 73 (a, b), 74 (a, b) The air that has flowed to the space 54ac is discharged. As a result, according to the air duct 51, it is possible to blow air to both ends in the longitudinal direction B inside the shield case 40 of the charging device 4, and the air duct 51 exists at both ends inside the shield case 40. Unnecessary items such as discharge products can be efficiently discharged to the outside.

  When there are three or more parts that are limited in the short direction C of the charging device 4, three or more ventilation parts of the third suppression part 63 in the air duct 51 may exist.

  The blocking members 64, 66, and 68 that constitute the three suppressing portions 61 to 63 in the air duct 51 are configured as ones that are integrally formed using the same material as the air duct 51, or What is necessary is just to comprise as the thing different from the ventilation duct 51 using the same material or a different material. Further, when the third suppressing portion 63 is configured to be closed with the air permeable member (75) described above, the air permeable member is also configured to be integrally formed using the same material as the air duct 51. Alternatively, the air duct 51 may be configured separately from the air duct 51 using the same material or a different material.

  As the suppression part in the air duct 51, although the case where the three suppression parts 61, 62, and 63 were provided in Embodiment 1, other suppression parts other than the three suppression parts 61, 62, and 63 were shown. It may be provided additionally. About the other suppression part, it is desirable to provide additionally in the site | part of the upstream of the flow direction of the 1st suppression part 61 among the channel | path parts 54. FIG.

  In addition, as the air duct 51, the whole shape is not limited to the shape exemplified in the first embodiment, and other shapes can be applied, for example, the whole as illustrated in FIG. You may apply the ventilation duct 510 (510A-510C) which consists of a shape.

  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 24 is not installed, that is, a so-called corotron type charging device. The charging device 4 may be one that uses one or three or more corona discharge wires 41. In addition, the long target structure to which the blower 5 is applied may be 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. In addition, it may be a long structure in which a plurality of air blowing portions other than the corona discharger exist along the longitudinal direction.

  Further, the image forming apparatus 1 is not particularly limited in the configuration of the image forming method and the like as long as the image forming apparatus 1 is equipped with a long target structure that needs to be blown with air by applying the blower 5. If necessary, an image forming apparatus that forms an image made of a material other than the developer may be used.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 4 ... Charging apparatus (elongate target structure, corona discharger)
5 ... Blower 41 ... Corona discharge wire (discharge member)
43c, 43d ... Positions 45, 46 facing the discharge wire ... Parts 50 selected in the short direction of the charging device 50 ... Blower 51 ... Blower duct (blower pipe)
52 ... Inlet 53A, 53B ... Outlet 54 ... Passage portion 54a ... Passage space 54B ... First bending passage portion 54C ... Second bending passage portion 61 ... First suppression portion 62 ... Second suppression portion 63 ... Third suppression portion 65 ... Gap (gap in the first suppression part)
67 ... Gap (gap in the second suppressing portion)
71, 72 ... Ventilation part B ... Longitudinal direction C ... Short direction E ... Air (flow)
R: Direction of air flow

Claims (9)

An inlet for taking in air;
It is arranged in a state facing a longitudinal portion of a long target structure to which air taken in from the inlet is blown, and has a long opening shape parallel to the longitudinal portion of the target structure and the inlet. Outlets with different opening shapes;
A passage portion in which a passage space for flowing air is formed by connecting between the inlet and the outlet;
A plurality of restraining portions that are provided at different portions in the direction of flowing air in the passage space of the passage portion, each of which has a shape extending in parallel with the longitudinal direction of the opening shape of the outlet, and suppresses the flow of air. Prepared,
As the plurality of suppression units,
A first suppression unit that is provided in a first portion between the inlet and the outlet of the passage unit and suppresses the flow of air by causing a long gap along the longitudinal direction;
A length along the longitudinal direction at least in the center of the short side direction perpendicular to the longitudinal direction of the second part is provided in the second part of the passage part downstream of the first restraining part in the flowing direction. A second suppression unit that suppresses the flow of air by causing a small gap;
Of the passage portion, provided at a third portion downstream of the second restraining portion in the flowing direction, parallel to the longitudinal direction at a plurality of positions shifted from the center of the short direction of the third portion. A third restraining portion for restraining the flow of air by causing a plurality of extending ventilation portions to exist as the outlet;
An air duct characterized by comprising at least. The passage portion is bent at at least one place,
The first portion exists upstream of the flow direction than the most downstream bent portion that is bent toward the outlet of the passage portion and is located on the most downstream side of the flow direction,
The blast pipe according to claim 1, wherein the second part and the third part exist downstream in the direction from the most downstream bent part.   The ventilation pipe according to claim 1 or 2, wherein the plurality of ventilation parts of the third suppression part are provided as two ventilation parts having the same distance from the gap of the second suppression part.   4. The blower pipe according to claim 1, wherein the plurality of ventilation portions of the third suppression portion have portions extending toward both ends in the longitudinal direction toward a central portion in the lateral direction. The target structure is a corona discharger having a linear discharge member installed along its longitudinal direction,
5. The plurality of positions shifted from the center in the short direction of the third suppressing portion are positions corresponding to positions shifted from positions facing the discharge members of the corona discharger. Air duct. A blower for sending air; and the blower pipe according to any one of claims 1 to 5,
The blower characterized by taking in the air sent from the said blower from the inlet_port | entrance of the said blower pipe. The target structure is a corona discharger having a linear discharge member installed along its longitudinal direction,
The blower device according to claim 6, wherein the plurality of positions of the third suppression unit that are shifted from the center in the short direction correspond to positions that are shifted from positions that face the discharge member of the corona discharger. A long target structure to be blown with air;
A blower that blows air toward a longitudinal portion of the target structure,
An image forming apparatus, wherein the blower is configured by the blower according to claim 6. The target structure is a corona discharger having a linear discharge member installed along the longitudinal direction,
The blower device according to claim 8, wherein the plurality of positions of the third suppression unit that are displaced from the center in the short direction correspond to positions that are displaced from positions that face the discharge member of the corona discharger.

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