JP2014203039A - Air duct and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air duct capable of discharging air from an exit in such a state that unevenness of air velocity in both directions corresponding to the longitudinal direction of a long target structure and a short-length direction orthogonal to the longitudinal direction is reduced.SOLUTION: The air duct comprises: an entrance for taking in the air; an exit 53 for blowing the air taken in from the entrance along the longitudinal direction of a corona discharger 4; a main body part in which a passage space 54a for flowing the air is formed by connecting the entrance and the exit 53; and first and second suppression parts 61 and 62 suppressing the flowing of the air. The air duct further includes a screen member 80 arranged in the passage space 54a between the first suppression part 61 and the second suppression part 62 and partitioning the passage space 54a into a space 81A located on the upstream side and a space 81B located on the downstream side in an air flowing direction.

Description

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

  In an image forming apparatus that forms an image composed of a developer on a recording sheet, for example, a process of charging or discharging a latent image holder such as a photoconductor, a process of transferring an unfixed image to a recording sheet, and the like Use a corona discharge device that performs corona discharge.

  In addition, in the corona discharge device, a blower that blows air toward the component parts is also provided to prevent unnecessary components such as paper dust and discharge products from adhering to the component parts such as the discharge wires and grid electrodes. May be. The blower in this case is generally composed of a blower that sends air and a duct (blower pipe) that guides and sends the air sent from the blower to a target structure such as a corona discharge device.

  Conventionally, various improvements and the like have been made for the air blower and the like so that air can be uniformly blown in the longitudinal direction of the components such as the discharge wires. In particular, as such a blower device, a configuration in which the shape of the passage space through which the air of the duct flows is formed in a special shape, or a configuration in which a rectifying plate for adjusting the direction of air flow is installed in the passage space of the duct The air blower etc. which employ | adopt another structure which is illustrated below instead of employ | adopting are proposed.

  As an air duct for guiding the air of the blower fan to the corona discharge device, a partition wall is formed in the air duct along the longitudinal direction of the corona discharge device (shield case), and the front side of the partition wall Thus, there are known a blower and a corona discharge device employing an air duct in which the pressure of an air flow (air flow) sent from a blower fan is temporarily increased (Patent Document 1).

  According to Patent Document 1, according to the air blower and the corona discharge device, the airflow flowing through the duct is made uniform along the longitudinal direction of the shield case when passing through the partition wall, and becomes a uniform flow. It is shown that it will be blown into the case. Further, Patent Document 1 shows that the partition wall may be constituted by an air filter provided so as to block the flow path in the air duct.

JP-A-10-198128

  The problem to be solved by the present invention is that the air sent from the blower is taken in from the inlet, and the air is directed in a direction perpendicular to the longitudinal direction with respect to the longitudinal portion of the long target structure to be blown. As a blower pipe formed so that it flows along the opening and the inlet and outlet are different from each other, the air is drawn from the outlet of the blower pipe without increasing the complexity and size of the apparatus. An object of the present invention is to provide a blower pipe that can be discharged in a state in which unevenness of wind speed in both directions corresponding to the longitudinal direction and the short direction perpendicular to the longitudinal direction is reduced.

The invention described in claim 1 is arranged in a state of facing an inlet for taking in air and a longitudinal portion of the long target structure to which the air taken in from the inlet is to be blown, and the longitudinal direction of the target structure. It is formed with a long opening shape parallel to the direction part, and an outlet formed with an opening shape different from the inlet and a passage space for flowing air between the inlet and the outlet are formed. The main body,
A plurality of restraining portions that are provided at different portions in the direction of flowing air in the passage space of the main body portion, and that restrain the flow of air, and
Among the plurality of suppression portions, disposed in the passage space between the downstream suppression portion in the downstream portion of the passage space in the direction of flowing air and the suppression portion located upstream of the downstream suppression portion, It is a blower pipe characterized in that a partition member is provided that partitions the passage space into a space located on the upstream side and a space located on the downstream side along the direction in which the air flows.

  According to the second aspect of the present invention, the most downstream suppression portion provided in the most downstream portion of the suppression portion in the direction in which the air flows in the passage space has a plurality of ventilation portions. The blower pipe according to claim 1, wherein the blower pipe is formed so as to be in a state of being closed by a ventilation member that is scattered.

  The invention described in claim 3 is characterized in that the volume ratio between the space located on the upstream side and the space located on the downstream side is changed according to the length of the partition member. It is a blast tube.

  The invention described in claim 4 is characterized in that the volume ratio between the space located on the upstream side and the space located on the downstream side is changed according to an angle formed by the partition member and the direction in which the air flows. Item 3. The blast tube according to item 1 or 2.

  The invention described in claim 5 is characterized in that the volume ratio of the space located on the upstream side and the space located on the downstream side is changed according to the position along the direction in which the air flows of the partition member. It is a ventilation pipe of Claim 1 or 2.

Invention of Claim 6 is equipped with the air blower which sends air, and the ventilation pipe in any one of Claims 1 thru | or 5,
It is a blower characterized by taking in air sent from the blower from an inlet of the blower pipe.

The invention described in claim 7 is a long object 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 invention described in claim 8 is the image forming apparatus according to claim 7, wherein the target structure is a corona discharger.

  According to the first aspect of the present invention, as compared with the case where the configuration of the present invention is not provided, the longitudinal portion of the long target structure to which the air sent from the blower is taken in from the inlet and the air is blown In contrast, the air blows out from the outlet so that the air flows along a direction perpendicular to the longitudinal direction, and the inlet and outlet are formed with different opening shapes, resulting in an increase in complexity and size of the apparatus. In addition, air can be emitted from the outlet of the blower pipe in a state in which the unevenness of the wind speed in both directions corresponding to the longitudinal direction of the long target structure and the short direction perpendicular to the longitudinal direction is reduced.

  According to the invention described in claim 2, compared with the case where the configuration of the invention is not provided, air is discharged from the outlet of the blower pipe in the longitudinal direction of the long target structure and the short direction perpendicular to the longitudinal direction. It can be put out in a state in which the unevenness of the wind speed in both corresponding directions is reduced.

  According to the invention described in claim 3, it is possible to further reduce the unevenness of the wind speed corresponding to the short direction perpendicular to the longitudinal direction of the target structure with a simple structure as compared with the case where the structure of the invention is not provided. Can do.

  According to the invention described in claim 4, it is possible to further reduce the unevenness of the wind speed corresponding to the short direction perpendicular to the longitudinal direction of the target structure with a simple structure as compared with the case where the structure of the invention is not provided. Can do.

  According to the invention described in claim 5, it is possible to further reduce the unevenness of the wind speed corresponding to the short direction perpendicular to the longitudinal direction of the target structure with a simple structure as compared with the case where the structure of the invention is not provided. Can do.

  According to the invention described in claim 6, it is possible to further reduce the unevenness of the wind speed corresponding to the short direction perpendicular to the longitudinal direction of the target structure with a simple structure as compared with the case where the structure of the invention is not provided. Can do.

  According to the seventh aspect of the present invention, as compared with the case where the configuration of the invention is not provided, the unevenness of the wind speed corresponding to the short direction perpendicular to the longitudinal direction of the target structure is further reduced with a simple configuration. Can do.

  According to the invention described in claim 8, the unevenness of the wind speed corresponding to the longitudinal direction and the transverse direction of the air with respect to the corona discharger of the blower device can be further reduced with a simple configuration as compared with the case where the configuration of the invention is not provided. Can be reduced.

It is explanatory drawing which shows the outline | summary of the image forming apparatus to which the air blower based on Embodiment 1 etc. of this invention is applied. 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 air blower 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 of FIG. 3 is seen from upper direction. It is a figure 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 state of operation | movement etc. of the air blower as a comparative example. It is explanatory drawing which shows the state of operation | movement, etc. of the air blower of FIG. It is a graph which shows the result of the evaluation test which measured the wind speed state in the exit of the ventilation duct in the air blower of FIG. It is a graph which shows the result of the evaluation test which measured the wind speed state in the exit of the ventilation duct in the air blower of FIG. It is explanatory drawing which shows the air blower (blower duct) which concerns on Embodiment 2. FIG. It is explanatory drawing which shows the air blower (blower duct) which concerns on Embodiment 3. FIG. It is explanatory drawing which shows the air blower (blower duct) which concerns on Embodiment 4. FIG. It is a graph which shows the result of the evaluation test which measured the wind speed state in the exit of the ventilation duct in the air blower of FIG.11 and 12. It is upper surface explanatory drawing which shows the example of various forms of a ventilation duct.

  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 3 show an image forming apparatus to which the blower according to the first embodiment is applied. FIG. 1 shows an outline of the entire image forming apparatus, FIG. 2 shows a charging device used as the image forming apparatus, which is a target structure to which air should be blown from the blower, and FIG. An overview of the device is shown.

  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, the image forming unit 20 for transferring to the paper 9, the paper feeding device 30 for storing and transporting the paper 9 supplied to the image forming unit 20, and the toner image formed by the image forming unit 20 are fixed to the paper 9 A fixing device 35 is installed. In the first embodiment, only one image forming unit 20 is illustrated, but an image forming unit including a plurality of image forming units 20 may be used.

  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 including the corona discharger includes a rectangular top plate 40a and a side plate 40b that hangs down from a long side extending along the longitudinal direction B of the top plate 40a. , 40c and a shield case (covering member) 40 having an external shape, 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 Two corona discharge wires 41A and 41B that are attached between the end support members so as to pass through the internal space of the shield case 40 and extend almost linearly, and a lower opening portion of the shield case 40 at its lower part A grid-like grid electrode (electric field adjustment plate) 42 that is attached in a state of covering the opening and existing between the corona discharge wire 41 and the peripheral surface of the photosensitive drum 21 is provided. It is, and a corona discharger so-called scorotron type. Reference numeral 40d shown in FIG. 4 and the like is a partition wall (partition member) that partitions the space in which the two corona discharge wires 41A and 41B are arranged.

  Further, in the charging device 4, the corona discharge wires 41 </ b> A and 41 </ b> B are opposed to the peripheral surface of the photosensitive drum 21 with a predetermined interval (for example, a discharge gap) and along the direction of the rotation axis of the photosensitive drum 21. Are arranged so as to be present at least in the image formation target area. The charging device 4 is configured to apply a charging voltage to the corona discharge wires 41A and 41B (between the photosensitive drum 21) from a power supply device (not shown) when an image is formed. In the charging device 4, a voltage for adjusting the charging potential of the photosensitive drum 21 is applied to the grid electrode 42 from a power supply device (not shown).

  In addition, the charging device 4 is applied to the corona discharge wires 41 and the grid electrodes 42 with the use thereof, such as paper dust of the paper 9, discharge products generated by corona discharge, and substances (unnecessary items) such as toner external additives. As a result of adhesion and contamination, corona discharge may not be performed sufficiently or uniformly, and charging defects such as uneven charging may occur. Therefore, the charging device 4 has a blower 5 for blowing air against the corona discharge wire 41 and the grid electrode 42 in order to prevent or suppress unwanted substances from adhering to the corona discharge wire 41 and the grid electrode 42. Is attached. An opening 43 for taking in air 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 sheet feeding device 30 accommodates a plurality of sheets 9 of a required size and type used for image formation in a stacked state, and a sheet container 31 such as a tray type or a cassette type, and the sheet container And a delivery device 32 that sends out the sheets 9 accommodated in the sheet 31 one by one toward the conveyance path, and is configured to send out the sheets 9 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 through which the sheet 9 is mainly conveyed. The conveyance path of the sheet 9 includes a plurality of sheet conveyance roll pairs 33a and 33b, a conveyance guide member (not shown), and the like.

  The fixing device 35 is heated in a roll form, a belt form, or the like in which a surface temperature is heated and held at a required temperature by a heating unit inside a housing 36 in which an introduction port and a discharge port through which the sheet 9 passes are formed. A rotating body 37 and a pressurizing rotating body 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 rotating body 37 are provided. The fixing device 35 performs fixing by introducing and passing the sheet 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 sheet 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, the electrostatic latent image formed on the photosensitive drum 21 is developed with the toner charged in the required polarity supplied from the developing roll 24a when passing through the developing device 24, and is thus a toner image. As visualized.

  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 paper 9 is transferred by the transfer device 25. The peripheral surface of the photosensitive drum 21 after the transfer is cleaned by a cleaning device 26.

  Subsequently, the sheet 9 on which the toner image is 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. The toner image is melted and fixed on the paper 9 by being heated and pressurized when passing through the fixing processing section between the rotating body 38 and the rotating body 38. After the fixing is completed, the sheet 9 is discharged from the fixing device 35 and is transported and stored in a paper discharge storage unit (not shown) formed outside the housing 10 or the like.

  Thus, a single color image formed with one color toner is formed on one side of one sheet of 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.

  Next, the blower 5 will be described.

  As shown in FIGS. 1 and 3, the blower 5 is a blower 50 having a rotating fan that sends air, and a blower that takes in the air sent from the blower 50 and directs it to the charging device 4 to be blown and ejects it. And an air duct 51 as a tube.

  As the blower 50, for example, a radiant flow type blower fan is used, and is driven and controlled so as to send a required amount of air. 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. The outlet 53 is arranged in a state facing the portion (the upper surface 40 a of the shield case 40) and discharges the air so as to flow along the direction orthogonal to the longitudinal direction B, and the air is connected between the inlet 52 and the outlet 53. And a main body portion 54 in which a passage space 54a for flowing the water is formed.

  One end of the main body 54 of the air duct 51 is opened with an inlet 52, the other end along the longitudinal direction B of the charging device 4 is closed, and the whole is along the longitudinal direction B of the charging device 4. A rectangular tube-shaped introduction passage portion 54A formed so as to extend in a substantially horizontal direction (a direction substantially parallel to the coordinate axis X) in a state where the width of the passage space is widened from a portion near the other end of the introduction passage portion 54A. The first bent passage portion 54B (see FIG. 4) having a rectangular tube shape formed so as to be bent substantially at right angles to the first bent passage portion 54B and the width of the passage space from the one end portion of the first bent passage portion 54B remain the same. The second bending passage portion 54 </ b> C is formed to be bent in the vertical direction (a direction substantially parallel to the coordinate axis Y) and extend toward the charging device 4. An outlet 53 having an opening shape slightly narrower than the cross-sectional shape of the passage space at the end portion is formed at the end portion of the second bent passage portion 54C (however, the length in the longitudinal direction of the rectangular shape is substantially the same). is there.). 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 along the longitudinal direction B).

  More specifically, as shown in FIG. 3, the main body portion 54 of the air duct 51 includes an introduction passage portion 54A formed in a rectangular tube shape along the longitudinal direction B of the charging device 4, and the introduction passage portion 54A. The width of the passage space from the position corresponding to one end portion (end portion on the inlet side) along the longitudinal direction B of the charging device 4 in the direction from the inlet 52 to the other end portion, to the position corresponding to the other end portion. A square tube-shaped first bent passage portion 54B formed to be bent and extend substantially at a right angle in a substantially horizontal direction (a direction substantially parallel to the coordinate axis X) in an expanded state is provided. The first bending passage portion 54B is provided up to a position corresponding to the upper portion of the charging device 4 in a direction orthogonal to the longitudinal direction B of the charging device 4, and the first bending passage portion 54B has a first end portion at the first end portion. A second passage formed from one end of the bent passage portion 54B is bent in the vertical direction (a direction substantially parallel to the coordinate axis Y) and extends toward the charging device 4 while maintaining the same width of the passage space. A bent passage portion 54C is provided.

  As shown in FIG. 3, the inlet 52 of the air duct 51 is formed so that the opening shape is substantially square. 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. Further, the outlet 53 of the air duct 51 is formed so that its opening shape is a long shape (for example, a rectangle) parallel to the longitudinal direction B portion 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. In addition, even when the inlet 52 and the outlet 53 have the same shape, when the opening areas are different from each other (when they are similar in shape), they are included in the relationship of being formed with different opening shapes. .

  Here, in the air duct 51 in which the inlet 52 and the outlet 53 are formed in different opening shapes as described above, the cross-sectional shape of the passage space 54 a is in the middle of the main body portion 54 that connects the inlet 52 and the outlet 53. There is a part to be changed. Incidentally, in this air duct 51, the cross-sectional shape of the substantially square passage space 54a of the introduction passage portion 54A has a rectangular passage space that extends only in the horizontal direction (regardless of the height) in the first bent passage portion 54B. The cross-sectional shape is changed to 54a. 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 54a that is abruptly widened in the first bent passage portion 54B.

  Further, in the case of the air duct 51 in which such a portion where the cross-sectional shape of the passage space 54a changes is present, the air flow is disturbed in the portion where the cross-sectional shape changes, such as separation or vortex. Even if air having a uniform wind speed is taken in, the air speed from the outlet 53 tends to be uneven. Note that the tendency of the air velocity of the air exiting from the outlet 53 to be ultimately non-uniform in this way changes the direction in which air flows (progresses) in the air duct 51 regardless of whether or not the cross-sectional shape of the passage space 54a changes. This also occurs in the same way.

  15a to 15c show typical examples 510A to 510C of air ducts in which the inlet 52 and the outlet 53 are formed in different opening shapes. In the drawing, the 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. Further, in the figure, when the lengths of the arrows are the same, it indicates that the wind speed is the same, and when the lengths are different, it indicates that 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 air flow direction 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.

  Therefore, as shown in FIGS. 3 to 6 and the like, the air duct 51 of the air blower 5 includes two restraining portions that restrain the air flow in different portions in the direction of the air flow in the passage space 54a of the main body portion 54. 61 and 62 are provided, and the most downstream suppression portion 62 provided at the most downstream portion (including the outlet 53) in the flow direction of the passage space 54a of the two suppression portions 61 and 62 includes The passage space (including the opening of the outlet 53) in the most downstream part is formed so as to be closed by a breathable member 70 having a plurality of ventilation portions 71.

  The first restraining portion 61 is upstream of the second restraining portion 62 located on the most downstream side in the direction of flowing air, and the direction of flowing air in the passage space 54a of the first bending passage portion 54B (reference E). It is provided in the site | part which becomes an upstream of the direction of the arrow shown by. In addition, the first suppression unit 61 is configured to have a gap 63 having a shape extending in a direction parallel to the longitudinal direction of the opening shape of the outlet 53 (the same direction as the longitudinal direction B of the charging device 4).

  As shown in FIG. 4, the first suppressing portion 61 in the first embodiment is a plate-shaped partition member in the passage space 54a of the bent passage portion 54B without changing the outer shape of the first bent passage portion 54B. 64 is made to exist. Specifically, the partition member 64 closes the upper portion of the passage space 54a of the first bent passage portion 54B, and the lower end portion 64a of the member has a required interval H with respect to the bottom portion of the passage space 54a. Thus, a structure in which a gap 63 exists in the lower part of the passage space 54a is formed. The partition member 64 is formed by integrally molding with the same material as the duct 51, or is formed with a material different from the duct 51.

  The height H, the path length M, and the width (length in the longitudinal direction) W of the gap 63 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. It is selected and set in consideration of the size (capacity) of the duct 51 and the flow rate per unit time of air to be passed through the duct 51 or the charging device 4. For example, the height H of the gap 63 is not limited to the same dimension in the width direction, and can be set to a dimension that is uniformly or partially changed from the above viewpoint.

  The second most restricting portion 62 at the most downstream side closes the passage space (opening) at the end portion (exit 53) of the second bent passage portion 43C by the air-permeable member 70 having the plurality of air-permeable portions 71. It is formed with.

  As shown in FIG. 6, each of the plurality of passage portions 71 is a through hole extending so that each opening shape is substantially circular and penetrates linearly. Further, for example, the plurality of ventilation portions 71 are arranged at equal intervals along the longitudinal direction B of the opening shape of the outlet 53 and there are four rows in the short direction C perpendicular to the longitudinal direction at the same intervals as the above-described equal intervals. They are lined up like this. As a result, the plurality of vent holes 71 are formed so as to be scattered throughout the passage space at the end of the second bent passage portion 54C or the entire 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. Further, the plurality of ventilation portions 71 are preferably formed so as to be scattered substantially uniformly (with a substantially constant density) with respect to the opening region of the outlet 53, but the air flowing out from the outlet 53 As long as it does not appear uneven, it may be formed so as to exist in a slightly dense state.

  The breathable member 70 may be formed by integrally molding with the same material as the duct 51, or may be formed with a material different from the duct 51. 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 duct 51 and the flow rate per unit time of the air to be passed through the duct 51 or the charging device 4 are set.

  By the way, in the ventilation duct 51 comprised as mentioned above, as shown in FIG. 4, the 1st suppression part 61 is the 2nd suppression part located in the most downstream in the passage space 54a of the 1st bending channel | path part 54B. It is provided at a site on the upstream side in the direction E of flowing air from 62. The first restraining portion 61 is configured by having a plate-like partition member 64 in the passage space 54a of the first bending passage portion 54B. The partition member 64 has a lower end portion 64a of the member that is a passage. It arrange | positions so that it may be in the state which opened the required space | interval H with respect to the bottom part of the space 54a, and, thereby, the structure where the clearance gap 63 exists in the lower part of the channel | path space 54a is formed.

  Therefore, the flow of air that has passed through the first suppression unit 61 increases in speed while passing through the gap 63, and the velocity component in the direction along the flow becomes relatively large. After flowing into the passage space 54a located between the second suppression portion 62 and the second suppression portion 62 made of a perforated plate is provided at a position corresponding to the outlet 53, the passage space 54a While the pressure is increased inside, it stays in a state where it circulates inside the passage space 54a, and the velocity distribution is made uniform.

  However, when the increase in the air pressure in the passage space 54 a located on the upstream side of the second suppression unit 62 is insufficient, the gap between the first suppression unit 61 and the second suppression unit 62 is The circulation and retention of air is not sufficiently performed in the passage space 54a located, and as shown in FIG. 7, the velocity component in the direction E along the flow that has passed through the first suppressing portion 61 is relatively large. The flow enters the perforated plate constituting the second suppressing portion 62 as it is, and the velocity distribution of the air flow that has passed through the second suppressing portion 62 is in the short direction C that intersects the longitudinal direction B of the charging device 4. The present inventors have found that there is a possibility of non-uniformity along the line. More specifically, when the pressure increase of the air in the passage space 54a is insufficient, the wind speed of the air blown from the downstream side along the short direction C of the second suppressing portion 62 is the upstream side. There is a possibility that the wind speed of the air blown from the air becomes higher and the wind speed of the air does not become uniform along the short direction intersecting the longitudinal direction of the charging device 4.

  Further, in order to make the velocity distribution of the air flow that has passed through the second suppression unit 62 uniform along the short direction C that intersects the longitudinal direction B of the charging device 4, the upstream of the second suppression unit 62. Although it is conceivable to increase the pressure of the air in the passage space 54a located on the side, in this case, the load on the blower 50 required to blow out the same amount of air from the outlet 53 increases. Become.

  Therefore, in this embodiment, as shown in FIG. 4, a passage space 54 a located on the upstream side along the flow of the air E of the most downstream restraint portion 62, the first restraint portion 62 and the most downstream side. A partition member 80 that partitions the passage space 54a into a space 81A located on the upstream side and a space 81B located on the downstream side along the flow of air is provided in the passage space 54a located between the control portion 62 ing. The partition member 80 is not a member that completely partitions the passage space 54a into the space 81A located on the upstream side and the space 81B located on the downstream side, but air between the upstream space 81A and the downstream space 81B. The space is divided into two spaces 81A and 81B while allowing distribution. Further, the partition member 80 also has a function of suppressing direct flow into the most downstream suppressing portion 62 when the flow of air that has passed through the first suppressing portion 62 hits. However, as the partition member 80, the flow of air that has passed through the first suppressing portion 62 does not necessarily directly abut, and the space 81A that is located on the upstream side and the space 81B that is located on the downstream side of the passage space 54a. Anything can be used as long as it is partitioned.

  The partition member 80 is formed in a flat plate shape, and may be formed by integrally molding the same material as the duct 51, or may be formed by a material different from the duct 51. The partition member 80 is provided in a portion of the ceiling portion that forms the second bending passage portion 54 </ b> B that faces the second suppression portion 62, and extends downward toward the second suppression portion 62. . Moreover, the partition member 80 is arrange | positioned in the position corresponding to the center part along the transversal direction C of the air permeable member 70 which comprises the 2nd suppression part 62, for example. Furthermore, as shown in FIG. 5, the partition member 80 is provided over the entire width W along the longitudinal direction B of the second bending passage portion 54B. The length L of the partition member 80 toward the second suppression portion 62 is set to a required value, and air is allowed to flow between the lower end of the partition member and the second suppression portion 62. A required gap G is formed. Moreover, the thickness T of the partition member 80 should just be what can maintain the position and shape as the partition member 80. FIG.

  The length L, the thickness T, and the width (length in the longitudinal direction) W of the partition member 80 determine the wind speed of the air that has flowed from the first suppressing portion 61 into the second bending passage portion 54C. It is selected and set from the viewpoint of making it as uniform as possible along the direction C, and is set in consideration of the size (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. Is done. For example, the length L of the partition member 80 is not limited to the same dimension in the width direction (B direction), and can be set to a dimension that is uniformly or partially changed from the above viewpoint.

  The amount (volume ratio) of air that flows into and stays in the upstream space 81A and the downstream space 81B varies depending on the length L of the partition member 80. When the length of the partition member 80 is relatively short (the gap G is large), the amount of air that flows into and stays in the space 81B on the downstream side from the space 81A on the upstream side increases. In addition, when the length L of the partition member 80 is relatively long (the gap G is small), the amount of air that flows into and stays in the space 81A upstream of the downstream space 81B increases.

  Hereinafter, the operation of the blower 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. 5, the air (E) sent from the started blower 50 is taken into the passage space 54 a of the main body portion 54 from the inlet 52 of the blower duct 51 through the connection duct 55.

  Subsequently, the air (E) taken into the blower duct 51 is sent so as to flow into the passage space 54a of the first bending passage portion 54B through the passage space 54a of the introduction passage portion 54A (arrows E1a, E1b, etc. in FIG. 5). reference). The air (E1) sent into the first bending passage portion 54B passes through the gap 63 of the first suppressing portion 61 and its traveling direction (air flowing direction) is changed to a substantially perpendicular direction. (Refer to the direction of arrow E2a in FIG. 5) and sent so as to flow into the passage space 54a of the first bent passage portion 54B (see directions of arrows E2a and E2b in FIG. 8).

  At that time, since the first suppressing portion 61 provided in the first bent passage portion 54B is formed of the gap 63 having a required height H, the first suppressing portion 61 provided from the introduction passage portion 54A to the first bent passage portion 54B. The air passing through the first suppression unit 61 is in a state in which the pressure is increased on the upstream side of the first suppression unit 61 and the flow rate is uniform along the longitudinal direction of the charging device 4. Pass 61.

  In this way, the air (E2) that flows through the gap 63 of the first suppressing portion 61 and flows into the passage space 54a of the first bent passage portion 54B is suppressed by the first suppressing portion 61 ( The pressure rises) and flows into the uniform state from the gap 63. Moreover, the air (E2) flowing into the passage space 54a of the first bent passage portion 54B is aligned in a direction substantially perpendicular to the longitudinal direction (B) of the outlet 53 when flowing out from the gap 63 of the suppressing portion 61. .

  Subsequently, the air (E2) that has flowed into the passage space 54a of the first bent passage portion 54B continues in a state of being bent in a substantially perpendicular direction downward from the first bent passage portion 54B. It moves to the passage space 54a of 54C. The air (E2) flowing into the passage space 54a of the second bending passage portion 54C flows into the passage space 54a of the second bending passage portion 54C having a larger volume than the passage space 54a of the introduction passage portion 54A and the space of the gap 63. As a result, the unevenness of the wind speed remaining in the passage space 54a of the second bent passage portion 54C is reduced.

  At this time, inside the passage space 54a of the second bent passage portion 54C, as shown in FIG. 8, the passage space 54a is divided into an upstream space 81A and a downstream space 81B along the air flow. A partition member 80 is provided. Therefore, the air (E2) that has flowed into the passage space 54a of the second bent passage portion 54C remains (stagnate) in a part E2a in the upstream space 81A, and the unevenness of the wind speed is reduced, and the remaining part E2b Remains (stays) in the space 81B on the downstream side, and uneven wind speed is reduced. As a result, the air E2 that has flowed into the passage space 54a of the second bent passage portion 54C is divided into the upstream space 81A and the downstream space 81B, and the unevenness of the wind speed is reduced, so that the air E2a and E2b flow. Wind speed unevenness existing between the upstream side and the downstream side along the width is also reduced in accordance with the volume ratio between the upstream space 81A and the downstream space 81B, and the short direction perpendicular to the longitudinal direction B of the charging device 4 The wind speed distribution along C is made substantially uniform.

  Finally, the air (E2) that has flowed into and stayed in the second bending passage portion 54C constitutes the most downstream suppression portion 62 provided at the end portion or the outlet 53 of the bending passage portion 54C, as shown in FIG. The air passing member 70 passes through a plurality of ventilation portions (holes) 71 and is blown out from the outlet 53 in a state in which the traveling direction is changed (see the direction and length of the arrow E3 in FIG. 8).

  At this time, the air (E3) blown out from the outlet 53 passes through the plurality of ventilation portions 71 of the breathable member 70 that is relatively narrower than the opening area of the outlet 53, and thus the flow is suppressed. (At this time, the pressure is also increased) and it is sent out. Further, the air (E3) blown out from the outlet 53 is scattered over the entire opening area of the outlet 53 and passes through the plurality of ventilation portions 71 formed under the same conditions, so that the area is substantially close to the opening shape of the outlet 53. It is sent out from the outlet 53 in a uniform state corresponding to the surface. Furthermore, the air (E3) blown out from the outlet 53 is sent out by changing the traveling direction in a direction substantially orthogonal to the longitudinal direction of the outlet 53.

  As described above, all of the air (E3) exiting from the plurality of ventilation portions 71 of the breathable member 70 is sent out with the traveling direction thereof being substantially perpendicular to the longitudinal direction of the outlet 53, and the wind speed is substantially uniform. It becomes a state. Further, the wind speed of the air (E3) exiting from the outlet 53 is substantially uniform in the longitudinal direction (B) of the opening shape (rectangle) of the outlet 53, and is also substantially uniform in the short direction C. become.

  At this time, as shown in FIG. 8, the inside of the second bending passage portion 54C is provided with a partition member 80 and partitioned into an upstream space 81A and a downstream space 81B along the air flow, By increasing the pressure inside the passage space 54a of the second bent passage portion 54C, it is possible to avoid the equalization, and it is possible to suppress an increase in the load on the blower 50.

  The air (E3) sent out from the outlet 53 of the air duct 51 is blown into the case 40 through the opening 43 formed in the upper surface 40a of the shield case 40 of the charging device 4, as shown in FIG. Two corona discharge wires 41A and 41B arranged in a space divided by a partition wall 40d existing at the center of the inside of the case 40 and a grid electrode 42 attached so as to exist in a lower opening of the case 40. Is sprayed on. At this time, the air blown to the corona discharge wires 41A and 41B and the grid electrode 42 comes out from the outlet 53 at substantially the same wind speed in both the longitudinal direction B and the short direction C of the outlet 53 of the blower duct 51. The corona discharge wires 41 </ b> A and 41 </ b> B and the grid electrode 42 are sprayed in a substantially equal state.

  Thereby, it is possible to keep away unnecessary materials such as paper dust, toner external additives, and discharge products that are to adhere to the two discharge wires 41A and 41B and the grid electrode 42, respectively. As a result, it is possible to prevent the charging performance from being deteriorated due to sparse adhesion of unnecessary materials to the discharge wires 41A and 41B and the grid electrode 42 in the charging device 4, and the peripheral surface of the photosensitive drum 21. Can be charged more uniformly (uniformly in both the axial direction and the circumferential direction along the rotational direction A). In addition, in the toner image formed by the image forming unit 20 including the charging device 4, and in the image finally formed on the paper 9, image quality defects (density unevenness, etc.) are generated due to charging defects such as uneven charging. A good reduced image can be obtained.

  FIG. 9 shows the results of an evaluation test in which the performance characteristics of the blower 5 (wind velocity distribution at the outlet of the blower duct) were examined.

  In the test, air with an air volume at which the average flow velocity from the outlet of the blower duct was about 1.0 m / second was introduced from the blower 50, and the wind speed in the longitudinal direction B of the outlet 53 was measured. For the measurement, an anemometer (manufactured by Cambridge Accusense Co., Ltd .: F900) is used. As shown in FIG. This was done by moving the anemometer in the longitudinal direction B at two locations, the end position P2 (post position) located downstream in the rotational direction A.

The entire shape of the air duct 51 is as shown in FIGS. 3 to 6, the inlet 52 has a substantially square opening shape of 22 mm × 23 mm, and the outlet 53 has a rectangular shape of 17.5 mm × 350 mm. The one having an opening shape was used. Further, the suppressing portion 61 is configured such that the height H of the gap 63 is inclined within a range of 1 to 2 mm, the path length M is 8 mm, and the width W is 345 mm. Further, the most downstream restraining part 62 includes a porous member 70 provided with vent holes 71 having a hole diameter of 1 mm and a length of 3 mm under the condition that the density is 0.42 / mm ² (= 42 / cm ² ). Used to configure.

  Further, the gap G between the lower end portion of the partition member 80 and the second restraining portion 62 is 6 mm, and the thickness T is 2 mm, and the center of the second restraining portion 62 along the short direction C is used. It was arranged at a position corresponding to the part.

  As shown in FIGS. 9 and 10, the average wind speed on the corona discharge wire 41 is almost 1 m / sec regardless of whether the partition member 80 is provided or not. The ratio of the wind speed between the end position P1 (pre position) located upstream of the rotation direction A of the drum 21 and the end position P2 (post position) located downstream of the rotation direction A provided the partition member 80. In this case, it was substantially uniform at 0.97. However, when the partition member 80 is not provided, 0.84 and the end position P2 (post position) located on the downstream side in the rotation direction A of the photosensitive drum 21. It was found that the wind speed of the wind was large and varied.

[Embodiment 2]
FIG. 11 shows an air blower according to Embodiment 2 of the present invention, and shows an air duct in the air blower.

  This blower device 5 has the same configuration as the blower device 5 according to the first embodiment except that the blower duct 51 is changed so that a part of the configuration is different. As shown in FIG. 11, the air duct 51 is configured such that the length L of the partition member 80 in the first embodiment is set longer than that in the first embodiment, and the end portion of the partition member 80 and the second suppression portion The gap G with 62 is set to be relatively small.

  In the blower 5, as shown in FIG. 11, the gap G between the end portion of the partition member 80 and the second suppressing portion 62 is set to be relatively small, so that it remains in the upstream space 81 </ b> A ( The flow rate of the air that stays (retains) increases relatively, and the flow rate of the air that remains (stays) in the space 81B on the downstream side relatively decreases. Therefore, the wind speed blown from the end position P1 (pre position) located on the upstream side in the rotation direction A of the photosensitive drum 21 of the outlet 53 rises, and the end position P2 (on the downstream side in the rotation direction A) ( The wind speed blown from the post position tends to decrease.

  Therefore, in the region where the wind speed blown from the end position P1 (pre position) located upstream of the rotation direction A of the photosensitive drum 21 at the outlet 53 along the longitudinal direction B of the charging device 4 is a partition member. By setting the length L of 80 to be long and reducing the gap G between the end of the partition member 80 and the second restraining portion 62, the end position P1 located on the upstream side in the rotation direction A of the photosensitive drum 21. The wind speed blown from the (pre position) can be increased, and as a result, the wind speed unevenness along the short direction C can be made uniform at any position along the longitudinal direction B of the charging device 4. It becomes.

[Embodiment 3]
FIG. 12 shows an air blower according to Embodiment 3 of the present invention, and shows an air duct in the air blower.

  This blower device 5 has the same configuration as the blower device 5 according to the first embodiment except that the blower duct 51 is changed so that a part of the configuration is different. As shown in FIG. 12, the air duct 51 is configured such that the front end (lower end) of the partition member 80 is inclined toward the upstream side with respect to the direction along the air flow. In addition, the position of the base end part (upper end part) of the partition member 80 is set to the same position as in the first embodiment.

  In the blower 5, as shown in FIG. 12, the partition member 80 is disposed at a position where the wind speed blown from the end position P1 (pre position) located upstream in the rotation direction A of the photosensitive drum 21 is high. By tilting toward the upstream side, the volume of the upstream space 81A is decreased and the volume of the downstream space 81B is increased, and the end position P1 (pre By reducing the wind speed blown from the position), the ratio of the wind speed blown from the end position P2 (post position) located downstream in the rotation direction A can be made substantially equal.

  Further, in this blower 5, at the position where the wind speed blown from the end position P1 (pre position) located upstream in the rotation direction A of the photosensitive drum 21 is slow, the partition member 80 is directed downstream. By tilting, the volume of the upstream space 81A is increased and the volume of the downstream space 81B is decreased, and the volume is blown from the end position P1 (pre position) located upstream in the rotation direction A of the photosensitive drum 21. By increasing the wind speed, the ratio of the wind speed blown from the end position P2 (post position) located downstream in the rotation direction A can be made substantially equal. Of course, the direction in which the partition member 80 is inclined is not limited to the upstream side in the direction along the air flow, but may be inclined toward the downstream side.

[Embodiment 4]
FIG. 13 shows an air blower according to Embodiment 4 of the present invention, and shows an air duct in the air blower.

  This blower has the same configuration as that of the blower according to Embodiment 1 except that a blower duct having a different configuration is used. As shown in FIG. 14, the air duct 51 is arranged by moving the position of the partition member 80 in the first embodiment to the upstream side in the direction along the air flow.

  In the blower 5, as shown in FIG. 13, in the position where the wind speed blown from the end position P1 (pre position) located upstream in the rotation direction A of the photosensitive drum 21 is high, the partition member 80 is disposed. By disposing the upstream space 81A relatively small by arranging it on the upstream side, and by arranging the partition member 80 on the downstream side at a slow position, the volume of the upstream space 81A is relatively large, Ratio of the wind speed blown from the end position P1 (pre position) located upstream in the rotation direction A of the photosensitive drum 21 and the wind speed blown from the end position P2 (post position) located downstream. Can be made substantially equal.

  FIG. 14 shows the results of an evaluation test in which the performance characteristics of the blower 5 (wind velocity distribution at the outlet of the blower duct) were examined. The test was performed under the same conditions as the evaluation test of the first embodiment.

  As shown in FIG. 14 (a), the average wind speed is the same as that of the first embodiment when the length of the partition member 80 is changed and when the inclination angle of the partition member 80 is changed. It was found that the average wind speed blown from the outlet 53 to the position of the corona discharge wire 41 hardly changed when 80 was used.

  On the other hand, as shown in FIG. 14B, when the length of the partition member 80 is set long, the volume of the upstream space 81A is decreased by inclining the photosensitive partition member 80 toward the upstream side. The wind speed of the air blown from the end position P1 (pre position) located upstream in the rotational direction A of the body drum 21 increases, and the partition member 80 is inclined toward the downstream side in the rotational direction A of the photosensitive drum 21. In this case, it can be seen that the wind speed of the air blown from the end position P2 (post position) located downstream in the rotation direction A of the photosensitive drum 21 increases.

  As described above, in the embodiment, by changing the length and installation angle of the partition member 80, the average value (air volume) of the wind speed is hardly changed, and the photosensitive drum 21 is moved upstream in the rotation direction A. The ratio between the wind speed of air blown from the end position P1 (pre position) located and the wind speed of air blown from the end position P2 (post position) located downstream is adjusted, and the outlet 53 It is possible to substantially align the wind speed along the short direction C.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 4 ... Charging apparatus 5 ... Air blower 41 ... Corona discharge wire 42 ... Grid electrode 50 ... Air blower 51 ... Air blow duct 52 ... Inlet 53 ... Outlet 54 ... Body part 54a ... Passage space 54A ... Introducing passage part 54B ... First bending passage portion 54C ... Second bending passage portion 80 ... Screen member B ... Longitudinal direction C ... Short direction E ... Air flow

Claims (8)

A long opening parallel to the longitudinal part of the target structure, which is arranged in a state facing the longitudinal part of the long target structure to which the air taken in from the inlet and the air taken in from the inlet should be blown An outlet formed in an opening shape different from that of the inlet, and a main body portion formed with a passage space for flowing air 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 main body portion, and that restrain the flow of air, and
Among the plurality of suppression portions, disposed in the passage space between the downstream suppression portion in the downstream portion of the passage space in the direction of flowing air and the suppression portion located upstream of the downstream suppression portion, A blower pipe characterized in that a partition member is provided that partitions the passage space into a space located on the upstream side and a space located on the downstream side along the direction in which the air flows.   A state in which the most downstream suppression portion provided in the most downstream portion of the suppression portion in the direction in which the air flows in the passage space blocks the passage space in the downstream portion with a ventilation member dotted with a plurality of ventilation portions. It forms so that it may become. The ventilation pipe | tube of Claim 1 characterized by the above-mentioned.   The blower pipe according to claim 1 or 2, wherein a volume ratio of the space located on the upstream side and the space located on the downstream side is changed according to a length of the partition member.   3. The air blow pipe according to claim 1, wherein a volume ratio between the space located on the upstream side and the space located on the downstream side is changed according to an angle formed by the partition member and a direction in which the air flows.   The blower pipe according to claim 1 or 2, wherein a volume ratio of the space located on the upstream side and the space located on the downstream side is changed according to a position of the partition member along a direction in which the air flows. . 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. 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 image forming apparatus according to claim 7, wherein the target structure is a corona discharger.

Images