Static electricity eliminating device and image forming apparatus

Abstract

A static electricity eliminating device includes: a corona discharge electrode facing a recording medium being conveyed and extending in an intersecting direction intersecting a conveying direction of the recording medium; a gas flow generating device that causes gas around the corona discharge electrode to flow toward a recording medium; and a suction duct which is disposed on the upstream side or the downstream side of the corona discharge electrode in the transport direction, extends in the intersecting direction, and sucks the gas flowing to the recording medium through the gas flow generating device.

Description

Technical Field

[0001] The present invention relates to a static elimination device and an image forming device. Background Art

[0002] The static electricity removal device described in patent document 1 comprises: a contact-type static electricity removal component, which has a static electricity removal part in contact with the charged medium being conveyed, and eliminates more than half of the charge on the charged medium; and a non-contact-type static electricity removal component, which is arranged at a position further downstream in the conveying direction of the charged medium than the contact-type static electricity removal component, and eliminates the residual charge on the charged medium after the static electricity is eliminated by the contact-type static electricity removal component in a non-contact state.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-167169 Summary of the Invention

[0004] The present invention aims to suppress stagnation of ozone-containing gas generated in the center of a corona discharge electrode extending in the cross direction on the surface of a recording medium, compared to the case where ozone-containing gas is discharged only from both ends of the recording medium in the cross direction.

[0005] The static electricity removal device involved in the first embodiment of the present invention is characterized in that it comprises: a corona discharge electrode, which is opposite to the recording medium being conveyed and extends in a cross direction intersecting the conveying direction of the recording medium; an airflow generating device, which causes the gas around the corona discharge electrode to flow toward the recording medium; and an intake duct, which is arranged on the upstream side or downstream side of the corona discharge electrode in the conveying direction, extends along the cross direction, and inhales the gas flowing toward the recording medium through the airflow generating device.

[0006] The static electricity removal device involved in the second embodiment of the present invention is characterized in that, in the static electricity removal device described in the first embodiment, the suction duct is arranged on the downstream side of the corona discharge electrode in the conveying direction, and a suppression component is provided on the upstream side of the corona discharge electrode in the conveying direction, and the suppression component extends along the cross direction to suppress the gas flowing toward the recording medium from flowing toward the upstream side of the corona discharge electrode in the conveying direction.

[0007] The static electricity removal device according to the third aspect of the present invention is characterized in that, in the static electricity removal device according to the second aspect,

[0008] The suppression member includes a discharge duct extending in the intersecting direction and discharging gas toward the recording medium on the upstream side of the corona discharge electrode in the conveying direction.

[0009] A fourth aspect of the present invention provides the static eliminator according to the third aspect, wherein the airflow generating device discharges the gas from the discharge duct.

[0010] A fifth aspect of the present invention is the static eliminator according to the third or fourth aspect, wherein the discharge duct and the intake duct extend in the intersecting direction and protrude relative to the corona discharge electrode on both sides in the intersecting direction.

[0011] The static electricity removal device involved in the sixth aspect of the present invention is characterized in that, in the static electricity removal device described in any one of the first to fifth aspects, the corona discharge electrode comprises: a box-shaped shielding shell that is open toward the recording medium and extends along the cross direction; and a discharge wire that is arranged inside the shielding shell and extends along the cross direction, and a through hole is formed on the bottom plate of the shielding shell through which gas passes using the flow of gas generated by the airflow generating device.

[0012] The static electricity removal device involved in the seventh embodiment of the present invention is characterized in that, in the static electricity removal device described in the sixth embodiment, the suction duct is arranged on the downstream side of the corona discharge electrode in the conveying direction, and the static electricity removal device is provided with a discharge duct, which extends along the cross direction and discharges gas toward the recording medium on the upstream side of the corona discharge electrode in the conveying direction through the flow of gas generated by the airflow generating device, and the flow path area of ​​the discharge duct and the opening area of ​​the through hole are determined in such a manner that the speed of the gas discharged from the discharge duct to the upstream side of the corona discharge electrode is faster than the speed of the gas from the corona discharge electrode toward the recording medium.

[0013] The image forming device involved in the 8th mode of the present invention is characterized in that it comprises: a conveying unit for conveying a recording medium; an image forming unit for forming an image on the recording medium conveyed by the conveying unit; and a static elimination device as described in any one of the 1st to 7th modes for eliminating static electricity on the charged recording medium being conveyed while forming an image.

[0014] Effects of the Invention

[0015] Compared to the case where ozone-containing gas is discharged only from both ends of the recording medium in the cross direction intersecting the conveying direction of the recording medium, the static electricity removal device involved in the first embodiment of the present invention can prevent the ozone-containing gas generated in the central part of the corona discharge electrode extending along the cross direction from stagnation on the surface of the recording medium.

[0016] Compared to the case where the gas flow is generated from the downstream side to the upstream side in the conveyance direction, the static electricity removal device according to the second aspect of the present invention can suppress an increase in the conveyance resistance applied to the recording medium.

[0017] Compared to the case where a resin plate is used to suppress the flow of gas to the upstream side, the static electricity removal device according to the third aspect of the present invention can suppress the recording medium being transported from being damaged by hitting the resin plate.

[0018] The static electricity removal device according to the fourth aspect of the present invention can reduce the number of components compared to a case where different airflow generating devices are used for discharging gas from the discharge duct and for flowing the gas with a high ozone concentration around the corona discharge electrode toward the recording medium.

[0019] Compared to a case where the corona discharge electrodes on both sides in the intersecting direction protrude relative to the discharge duct and the suction duct, the static electricity removal device according to the fifth aspect of the present invention can suppress ozone leakage in the intersecting direction.

[0020] Compared to a case where no through-hole is formed in the bottom plate of the shield case, in the static electricity removal device according to the sixth aspect of the present invention, the gas with a high ozone concentration around the corona discharge electrode flows toward the recording medium with a simple structure.

[0021] Compared to the case where the speed of the gas discharged from the discharge duct toward the recording medium is slower than the speed of the gas from the corona discharge electrode toward the recording medium, the static electricity removal device involved in the seventh aspect of the present invention can suppress the gas flowing from the corona discharge electrode toward the recording medium from flowing toward the upstream side of the conveying direction of the recording medium.

[0022] Compared to an image forming apparatus including a static eliminator that discharges ozone-containing gas only from both ends of a recording medium in a direction intersecting the conveyance direction of the recording medium, the image forming apparatus according to the eighth aspect of the present invention can suppress stagnation of ozone-containing gas inside the apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0024] Figure 1 is a schematic structural diagram showing an image forming apparatus according to a first embodiment of the present invention;

[0025] Figure 2 is a schematic diagram showing the configuration of a toner image forming portion of an image forming apparatus according to a first embodiment of the present invention;

[0026] Figure 3 is a perspective view showing a chain clamp of an image forming apparatus according to a first embodiment of the present invention;

[0027] Figure 4 is a perspective view showing a secondary transfer roller and the like of a transfer device according to a first embodiment of the present invention;

[0028] Figure 5 is a perspective view showing a heating roller, a pressure roller, and the like of an image forming apparatus according to a first embodiment of the present invention;

[0029] Figure 6 is a cross-sectional view showing a heating roller, a pressure roller, and the like of an image forming apparatus according to an embodiment of the present invention;

[0030] Figure 7 1 is an overall perspective view showing a static electricity removal device according to a first embodiment of the present invention;

[0031] Figure 8 This is a cross-sectional view of the static electricity removal device according to the first embodiment of the present invention, taken along a plane perpendicular to the depth direction;

[0032] Figure 9 This is an enlarged perspective view showing a corotron included in the static elimination device according to the first embodiment of the present invention;

[0033] Figure 10 is a cross-sectional view of the static electricity removal device according to the first embodiment of the present invention, taken along a plane perpendicular to the vertical direction;

[0034] Figure 11 (A) Figure 11 (B) is a perspective view showing the discharge port of the discharge duct and the suction port of the suction duct in the static electricity removal device according to the first embodiment of the present invention;

[0035] Figure 12 is a front view showing a static electricity removal device according to a comparative embodiment of the first embodiment of the present invention;

[0036] Figure 13 This is a cross-sectional view of the static electricity removal device according to the second embodiment of the present invention, taken along a plane perpendicular to the depth direction.

[0037] Explanation of symbols

[0038] 10-image forming device, 12-image forming unit, 44-discharge roller (an example of a conveying unit), 150-static removal device, 160-corona tube (an example of a corona discharge electrode), 162-shielding shell, 162a-bottom plate, 164-discharge wire, 166-through hole, 174-discharge duct, 176-fan (an example of an airflow generating device), 184-discharge duct, 350-static removal device, 378-guiding component (an example of a suppressing component). DETAILED DESCRIPTION

[0039] <First embodiment>

[0040] according to Figures 1 to 12An example of a static elimination device and an image forming apparatus according to the first embodiment of the present invention will be described. In each figure, arrow H indicates the vertical direction and the up-down direction of the apparatus; arrow W indicates the horizontal direction perpendicular to arrow H and the width direction of the apparatus; and arrow D indicates the horizontal direction perpendicular to arrows H and W and the depth direction of the apparatus.

[0041] The image forming apparatus 10 according to this embodiment is an electrophotographic image forming apparatus that forms a toner image on a sheet member P as a recording medium. Figure 1 As shown, the image forming apparatus 10 includes a storage portion 50 , an image forming portion 12 , and a control portion 18 that controls each portion.

[0042] (Accommodation portion 50)

[0043] like Figure 1 As shown, the storage section 50 includes a loading section 78 on which the sheet members P are loaded, and a delivery roller 58 that delivers the uppermost sheet member P loaded on the loading section 78 to the supply path 40 .

[0044] (Image Forming Unit 12)

[0045] like Figure 1 As shown, the image forming unit 12 is arranged above the housing portion 50. The image forming unit 12 includes a toner image forming unit 20 for forming a toner image; a transfer device 30 for transferring the toner image formed in the toner image forming unit 20 onto a sheet member P; a fixing device 100 for fixing the toner image onto the sheet member P; and a static eliminator 150 for eliminating static electricity on the sheet member P.

[0046] [Toner Image Forming Unit 20]

[0047] like Figure 1 As shown, a plurality of toner image forming units 20 are provided to form toner images for each color. The image forming unit 12 includes toner image forming units 20 for four colors: yellow (Y), magenta (M), cyan (C), and black (K). Figure 1 Y, M, C, and K shown here represent components corresponding to the above-mentioned colors.

[0048] The toner image forming section 20Y, the toner image forming section 20M, the toner image forming section 20C, and the toner image forming section 20K have basically the same configuration except for the toners used.

[0049] like Figure 1As shown, the toner image forming units 20Y, 20M, 20C, and 20K are arranged along a horizontal portion of a transfer belt 31 provided in the transfer device 30. In the following description, when the toner image forming units 20Y, 20M, 20C, and 20K are not specifically distinguished, the last letters are omitted.

[0050] like Figure 2 As shown, the toner image forming unit 20 includes an image holding member 21 that rotates in the direction of arrow A01 in the figure, and a charger 22 that charges the image holding member 21. The toner image forming unit 20 also includes an exposure device 23 that forms an electrostatic latent image by exposing the image holding member 21 charged by the charger 22, and a developing device 24 that develops the electrostatic latent image using toner to form a toner image.

[0051] [Transfer device 30]

[0052] like Figure 1 As shown, the transfer device 30 includes a transfer belt 31 as an intermediate transfer member, a plurality of rollers 32 , a primary transfer roller 33 , a transfer drum 36 , and a scraping member 38 .

[0053] The transfer belt 31 is endless and is wound around a plurality of rollers 32 in an inverted triangle shape. The toner image forming units 20Y, 20M, 20C, and 20K are arranged along the upper horizontal portion of the transfer belt 31. The transfer belt 31 is rotated in the direction indicated by arrow B by rotating at least one of the plurality of rollers 32.

[0054] In the following description, among the plurality of rollers 32, the roller 32 arranged so as to push out the inclined portion on one side (left side in the figure) of the transfer belt 31 in the width direction is referred to as roller 32a, and the roller 32 around which the portion on one side of the transfer belt 31 in the width direction is wound is referred to as roller 32b. Furthermore, the roller 32 arranged upstream of roller 32a in the winding direction of the transfer belt 31 is referred to as roller 32c.

[0055] The roller 32b functions as a driving roller that is rotationally driven by a driving force applied from the driving source 34. The roller 32c functions as a tensioning roller that applies tension to the transfer belt 31 by pressing the transfer belt 31 from its back surface.

[0056] The primary transfer roller 33 is disposed on the opposite side of the image holder 21 of each color across the transfer belt 31. The primary transfer roller 33 transfers the toner image formed on the image holder 21 to the transfer belt 31 at a primary transfer position T between the image holder 21 and the primary transfer roller 33.

[0057] The transfer drum 36 is arranged on the opposite side of the transfer belt 31 from the roller 32a and is driven to rotate. The transfer drum 36 transfers the toner image transferred to the transfer belt 31 to the sheet member P at a secondary transfer position NT between the transfer belt 31 and the transfer drum 36.

[0058] The scraping member 38 is disposed between the roller 32 a and the roller 32 b in the circling direction of the transfer belt 31 , and scrapes off the attached matter attached to the surface of the transfer belt 31 from the transfer belt 31 .

[0059] [Fixing Device 100]

[0060] like Figure 1 As shown, the fixing device 100 includes a chain gripper 66 and a main heating unit 120 that comes into contact with the sheet member P and heats the toner image.

[0061] -Chain Clamp 66-

[0062] The chain gripper 66 includes a pair of chains 72 , a front end holding portion 68 that holds the front end of the sheet member P, and sprockets 71 , 73 , 82 , 84 , and 86 .

[0063] like Figure 3 As shown, a pair of chains 72 are separated and arranged in the depth direction, and the chains 72 are formed into a ring shape. Figure 4 As shown, a pair of chains 72 are wound around a pair of sprockets 73 which are arranged at both ends of the transfer cylinder 36 in the axial direction and have the axial direction as the depth direction.

[0064] Furthermore, a pair of chains 72 are wound around a pair of sprockets 71 (see FIG. 1 ) which are arranged at one end and the other end of the axial direction of a pressurizing cylinder 140 described later and have the axial direction as the depth direction. Figure 5 ) On. Moreover, a pair of chains 72 is wound around a pair of sprockets 82, a pair of sprockets 84, and a pair of sprockets 86 that are spaced apart in the depth direction.

[0065] And, as Figure 1 As shown, the sprockets 71 arranged at both ends of the pressurizing cylinder 140 are arranged on one side (left side in the figure) and above the sprockets 73 arranged at both ends of the transfer cylinder 36 in the width direction.

[0066] Furthermore, when viewed from the depth direction, the pair of sprockets 82 are arranged below the sprocket 71. Furthermore, the pair of sprockets 86 are arranged below the sprockets 73 and 82, on one side in the width direction relative to the sprocket 73, and on the other side in the width direction relative to the sprocket 82. Furthermore, the pair of sprockets 84 are arranged so as to lift the portion of the chain 72 between the sprockets 82 and 86 from the bottom to the top.

[0067] like Figure 3As shown, the front end holding portion 68 includes a mounting member 75 extending in the depth direction and a clamper 76 mounted on the mounting member 75 . Portions on both sides of the front end holding portion 68 in the depth direction are respectively mounted to a pair of chains 72 .

[0068] A plurality of front end holding portions 68 are provided and are arranged at predetermined intervals along the circumferential direction (circular direction) of the chain 72 (see Figure 1 ).

[0069] The clamps 76 are provided in plurality and are mounted on the mounting member 75 at predetermined intervals in the depth direction. The clamps 76 have the function of holding the front end of the sheet member P. Specifically, the clamps 76 have claws 76a. Furthermore, a contact portion 75a (see FIG. 1 ) that contacts the claws 76a is formed on the mounting member 75. Figure 6 ).

[0070] The gripper 76 is configured to hold the sheet member P by sandwiching the front end of the sheet member P between the claw 76a and the contact portion 75a. Furthermore, in the gripper 76, the claw 76a is pressed against the contact portion 75a by a spring or the like, and is brought into contact with or separated from the contact portion 75a by the action of a cam or the like.

[0071] In this structure, the rotational force is transmitted to Figure 1 The sprockets 71 and 73 among the plurality of sprockets 71 , 73 , 82 , 84 , and 86 shown, and thus a pair of chains 72 are wound in the direction of arrow C in the figure.

[0072] When the front end holding portion 68 attached to the pair of chains 72 reaches the sprocket 73, the clamp 76 of the front end holding portion 68 clamps the front end of the sheet member P being conveyed along the supply path 40, thereby holding and receiving the sheet member P. The chain 72, which loops in the direction of arrow C, conveys the sheet member P held by the front end holding portion 68 toward the secondary transfer position NT. Furthermore, the looping chain 72 conveys the sheet member P toward the main heating section 120. Once the front end of the sheet member P has passed the main heating section 120, the front end holding portion 68 releases the front end of the sheet member P, and the chain clamp 66 delivers the sheet member P toward the discharge path 42. The sheet member P delivered to the discharge path 42 is then discharged to the exterior of the apparatus main body 10a.

[0073] -Main heating unit 120-

[0074] like Figure 1As shown, the main heating section 120 is located downstream of the secondary transfer position NT in the conveyance direction of the sheet member P (hereinafter referred to as the "sheet conveyance direction"). The main heating section 120 includes a heating roller 130 that contacts and heats the conveyed sheet member P, and a pressurizing cylinder 140 that presses the sheet member P toward the heating roller 130.

[0075] In this configuration, the pressure cylinder 140 presses the sheet member P toward the heating roller 130. Furthermore, the pressure cylinder 140 rotates due to the rotational force transmitted from a driving member (not shown). Furthermore, the heating roller 130 rotates as a slave of the rotating pressure cylinder 140. The sheet member P, onto which the toner image has been transferred, is then sandwiched and conveyed between the heating roller 130 and the pressure cylinder 140, whereby the toner image is heated and fixed to the sheet member P.

[0076] [Static elimination device 150]

[0077] like Figure 1 As shown, the static eliminator 150 is disposed in the discharge passage 42 downstream of the fixing device 100 in the conveyance direction of the sheet member P. Specifically, the discharge passage 42 is provided with a pair of discharge rollers 44 arranged in the width direction, and the static eliminator 150 is disposed between the pair of discharge rollers 44. The discharge rollers 44 are an example of a conveying unit. The static eliminator 150 will be described in detail later.

[0078] (Function of Image Forming Apparatus)

[0079] exist Figure 1 In the image forming apparatus 10 shown in FIG. 1 , a toner image is formed on a sheet member P in the following manner. First, Figure 2 The chargers 22 for each color shown uniformly negatively charge the surface of the image holder 21 for each color at a predetermined potential. Then, the exposure device 23 irradiates the charged surface of the image holder 21 with exposure light according to image data input from the outside to form an electrostatic latent image.

[0080] Thus, an electrostatic latent image corresponding to the image data is formed on the surface of each image holding member 21. Then, the developing device 24 of each color develops the electrostatic latent image and visualizes it as a toner image. Figure 1 The primary transfer rollers 33 of the transfer device 30 shown transfer the toner images formed on the surfaces of the image holding bodies 21 of the respective colors onto the transfer belt 31 at the primary transfer positions T.

[0081] Therefore, the sheet member P fed from the storage portion 50 to the supply path 40 by the feed roller 58 is transferred to the leading end holding portion 68 of the chain gripper 66 (see FIG. 1 ). Figure 3The sheet member P conveyed by the chain gripper 66 is sent toward the secondary transfer position NT. At the secondary transfer position NT, the toner image on the surface of the transfer belt 31 is transferred to the surface of the sheet member P as the sheet member P is conveyed between the transfer belt 31 and the transfer drum 36.

[0082] The fixing device 100 fixes the toner image transferred to the surface of the sheet P onto the sheet P, and the sheet P conveyed by the chain gripper 66 is sent to the discharge path 42. The sheet P sent to the discharge path 42 is discharged to the outside of the apparatus main body 10a.

[0083] (Main structure)

[0084] Next, the static electricity removal device 150 will be described.

[0085] like Figure 1 、 Figure 7 As shown, the static eliminator 150 is arranged on the opposite side of the discharge path 42 from the paper guide 46 provided along the discharge path 42 for discharging the sheet member P. Specifically, the paper guide 46 is arranged below the discharge path 42, and the static eliminator 150 is arranged above the discharge path 42.

[0086] The static electricity removal device 150 is in the shape of a rectangular parallelepiped extending in the depth direction. Figure 8 As shown, a corotron 160 for eliminating static electricity of the charged sheet member P by corona discharge and a recovery unit 170 for recovering ozone generated by the corona discharge are provided.

[0087] [Scorotron 160]

[0088] like Figure 8 As shown in FIG. 1 , the corotron 160 includes a shielding shell 162 as a frame and a discharge electrode to which voltage is applied, namely a discharge wire 164. The shielding shell 162 is made of stainless steel and is in a box shape with an opening on the discharge channel 42 side, extending in the depth direction. Figure 9 As shown, a plurality of circular through holes 166 are formed in a row in vertical and horizontal directions on a bottom plate 162a of a box-shaped shield case 162. The corotron 160 is an example of a corona discharge electrode.

[0089] The discharge wire 164 is formed of a metal wire such as tungsten and is arranged in the shield case 102 and extends in the depth direction.

[0090] In this configuration, a voltage is applied to the discharge wire 164 from a power source (not shown) to generate corona discharge, thereby eliminating static electricity from the charged sheet member P. Ozone is also generated by the corona discharge.

[0091] [Recovery Department 170]

[0092] like Figure 8 、 Figure 10 As shown, the recovery portion 170 is provided to cover the corotron 160 from both sides in the width direction, both sides in the depth direction, and the upper side in the vertical direction.

[0093] The collecting unit 170 includes a discharge unit 172 that discharges air toward the sheet member P conveyed along the discharge path 42 and a suction unit 182 that sucks the air discharged toward the sheet member P. Air is an example of gas.

[0094] -Discharge portion 172-

[0095] like Figure 8 As shown, the discharge unit 172 includes a discharge duct 174 and a fan 176 that blows (discharges) air toward the sheet member P conveyed through the discharge duct 174 .

[0096] The discharge duct 174 is in a box shape with an opening on the discharge channel 42 side, and extends in the depth direction. The discharge duct 174 includes a top plate 174a with a plate thickness direction in the vertical direction, a front plate 174b with a plate thickness direction in the width direction, and a back plate 174c with a plate thickness direction in the width direction and arranged on the downstream side of the front plate 174b in the sheet conveying direction. Figure 10 As shown, the discharge duct 174 includes a pair of side panels 174d whose plate thickness direction corresponds to the depth direction.

[0097] Furthermore, a corotron 160 is disposed inside the discharge conduit 174. Specifically, when viewed from the depth direction, Figure 8 As shown, a corotron 160 is disposed at the opening of the discharge duct 174 and with a gap 180a between the corotron 160 and the front plate 174b. Figure 10 As shown, the corotron 160 is disposed with gaps 180b between each of the pair of side panels 174d. In other words, gaps 180b are formed between the corotron 160 and the pair of side panels 174d on both sides of the corotron 160 in the depth direction. Furthermore, in other words, the discharge conduit 174 protrudes relative to the corotron 160 in the depth direction.

[0098] like Figure 7 As shown, the fan 176 is mounted on the top plate 174a, and a plurality of fans are arranged in a row in the depth direction. Figure 8 As shown by the arrow, the fan 176 blows (discharges) air toward the sheet member P conveyed through the discharge duct 174. The fan 176 is an example of an airflow generating device.

[0099] like Figure 8 、 Figure 11 As shown in FIG. 1A , guide portion 178 is provided at outlet 174e of discharge duct 174, with multiple guide portions 178 spaced apart in the depth direction. Guide portion 178 is plate-shaped, with end 178a on the upstream side of guide portion 178 in the sheet conveying direction positioned above end 178b on the downstream side. Furthermore, end 178b is positioned below the lower end of shield case 162.

[0100] In this structure, the fan 176 is operated to flow the air inside the discharge duct 174 toward the sheet member P (see FIG. Figure 8 Here, the air flowing toward the sheet member P is divided into three paths and then discharged toward the sheet member P.

[0101] In the first path, the air flowing in the direction of arrow A passes through the through hole 166 formed in the bottom plate 162a of the shield shell 162, flows through the inside of the shield shell 162, and is discharged to the sheet member P side (see FIG. Figure 8 In other words, the air with a high ozone concentration around the discharge wire 164 is discharged toward the sheet member P. Thus, the ozone generated by the corona discharge is discharged toward the sheet member P.

[0102] In the second path, the air flowing in the direction of arrow A flows through the gap 180a between the corotron 160 and the front plate 174b and is discharged toward the sheet member P side (see FIG. Figure 8 In other words, the air flowing in the direction of arrow A is discharged from the discharge port 174e of the discharge duct 174 toward the sheet member P side (refer to Figure 8 Here, the flow path area of ​​the discharge duct 174 and the area and number of the through-holes 166 formed in the bottom plate 162a of the shielding case 162 are determined so that the flow rate of the air discharged from the discharge port 174e toward the sheet member P is faster than the flow rate of the air flowing through the inside of the shielding case 162.

[0103] In the third path, the air flowing in the direction of arrow A flows through the gaps 180b formed on both sides of the corotron 160 in the depth direction and is discharged toward the sheet member P side (see FIG. Figure 10 As indicated by arrow D), the air in the discharge duct 174 flows through the first to third paths and is discharged toward the sheet member P.

[0104] -Suction section 182-

[0105] like Figure 8 As shown, the suction portion 182 includes a suction duct 184 and a guide portion 188 provided at a suction port 184 e of the suction duct 184 .

[0106] The suction duct 184 is in the shape of a box with an opening on the discharge channel 42 side, and extends in the depth direction. The suction duct 184 is arranged on the downstream side of the discharge duct 174 in the sheet conveying direction. In addition, the suction duct 184 includes a top plate 184a with the plate thickness direction in the up-down direction, a back plate 174c of the discharge duct 174, and a back plate 184c with the plate thickness direction in the width direction and on the downstream side of the back plate 174c in the sheet conveying direction. In addition, as Figure 10 As shown, the suction duct 184 includes a pair of side panels 184d whose plate thickness direction corresponds to the depth direction.

[0107] like Figure 8 、 Figure 11 As shown in FIG. 1B , guide portion 188 is provided at suction port 184e of suction duct 184, with multiple guide portions 188 spaced apart in the depth direction. Guide portion 188 is plate-shaped, with end 188a upstream in the sheet conveying direction positioned above end 188b downstream in the sheet conveying direction. Furthermore, end 188b is positioned below the lower end of back panel 184c.

[0108] And, as Figure 1 As shown, one end of an exhaust duct 194 is connected to the top plate 184 a of the suction duct 184 , and an exhaust fan 196 and an ozone filter 198 are provided at the other end of the exhaust duct 194 .

[0109] In this structure, from Figure 8 The air discharged toward the sheet member P by the discharge duct 174 shown in the figure flows through the first to third paths described above, flows toward the downstream side in the sheet conveying direction, is sucked into the suction duct 184, and is discharged.

[0110] (Function of the main structure)

[0111] Next, the operation of the static eliminator 150 will be described together with the static eliminator 250 according to the comparative embodiment. First, the configuration of the static eliminator 250 according to the comparative embodiment will be described, focusing on the differences from the static eliminator 150 according to the present embodiment.

[0112] [Structure of the static electricity removal device 250]

[0113] like Figure 12As shown, the static electricity removal device 250 involved in the comparative method includes: a corotron 160; and a fan 276, which is installed in a through hole (omitted symbol) formed on the bottom plate 162a of the shielding shell 162 of the corotron 160, and blows (exhales) air toward the sheet member P side through the inside of the shielding shell 162.

[0114] [Function of the static electricity removal devices 150 and 250]

[0115] like Figure 1 As shown, the sheet member P conveyed inside the image forming apparatus 10 is charged with static electricity at the secondary transfer position NT where the toner image is transferred. The statically charged sheet member P is conveyed along the discharge path 42 and faces the static eliminators 150 and 250 .

[0116] A voltage is applied to the discharge wire 164 of the corotron 160 of the static eliminator 150 or 250 to generate corona discharge, thereby eliminating static electricity on the sheet member P. Ozone is also generated by the corona discharge.

[0117] -Static elimination device 250-

[0118] In the static electricity removal device 250 according to the comparative embodiment, Figure 12 As shown, the fan 276 is in operation to cause the air inside the shield case 162 to flow toward the sheet member P (see FIG. Figure 12 As a result, ozone-containing air generated by corona discharge is discharged toward the sheet member P side.

[0119] At both sides in the depth direction, the air flowing toward the sheet member P passes through the outer side of the paper guide 46 in the depth direction and flows downwardly to be discharged ( Figure 12 arrow F).

[0120] On the other hand, in the center portion in the depth direction, the air flowing toward the sheet member P hits the sheet member P and stagnates on the surface of the sheet member P.

[0121] -Static elimination device 150-

[0122] In the static electricity removal device 150 according to this embodiment, Figure 8 As shown, the fan 176 in operation causes the air inside the discharge duct 174 to flow toward the sheet member P (see FIG. Figure 8 arrow A).

[0123] The air flowing in the direction of arrow A and then flowing through the first path passes through the through hole 166 formed in the bottom plate 162a of the shield case 162, flows through the inside of the shield case 162, and is discharged to the sheet member P side (see Figure 8As a result, ozone-containing air generated by corona discharge is discharged toward the sheet member P side.

[0124] Then, the air flowing in the direction of arrow A and then flowing through the second path is discharged from the discharge port 174e of the discharge duct 174 toward the sheet member P side (see FIG. Figure 8 arrow C).

[0125] Then, the air flowing in the direction of arrow A and then flowing through the third path flows through the gaps 180b formed on both sides of the corotron 160 in the depth direction and is discharged toward the sheet member P side (see FIG. Figure 10 arrow D).

[0126] Then, the ozone-containing air discharged from the discharge duct 174 through the first to third paths toward the sheet member P flows toward the downstream side in the sheet conveying direction, is sucked into the suction duct 184 , and is discharged.

[0127] Thus, unlike the static electricity removal device 250 according to the comparative embodiment, the static electricity removal device 150 according to this embodiment can suppress stagnation of the ozone-containing air generated in the central portion of the corotron 160 extending in the depth direction on the surface of the sheet member P.

[0128] (Summarize)

[0129] As described above, in static electricity removal device 150, air flowing toward sheet member P by operating fan 176 passes through through-holes 166 formed in bottom plate 162a of shield case 162, flows through the interior of shield case 162, and is discharged toward sheet member P. The air discharged toward sheet member P then flows downstream in the sheet conveyance direction, is drawn into suction duct 184, and is discharged. This prevents ozone-containing air generated in the center portion of corotron 160, which extends in the depth direction, from stagnating on the surface of sheet member P, compared to the case using static electricity removal device 250 according to the comparative embodiment.

[0130] Furthermore, in the static eliminator 150, ozone-containing air generated by corona discharge is discharged toward the sheet member P. The discharged ozone-containing air flows downstream in the conveyance direction and is sucked into the suction duct 184. Thus, compared to a case where the air discharged toward the sheet member P flows upstream in the conveyance direction and is sucked into the suction duct, an increase in the conveyance resistance applied to the sheet member P can be suppressed.

[0131] Furthermore, in the static eliminator 150, the ozone-containing air generated by corona discharge is discharged toward the sheet member P. This ozone-containing air is suppressed from flowing upstream in the conveyance direction by the air discharged toward the sheet member P from the discharge port 174e of the discharge duct 174. This prevents the conveyed sheet member P from being damaged by contact with the resin plate, compared to a case where the air flow upstream is suppressed using a resin plate.

[0132] Furthermore, in static electricity removal device 150, air flowing toward sheet member P by operating fan 176 flows through a flow path for discharge toward sheet member P through through-hole 166 formed in bottom plate 162a of shield case 162, and a flow path for discharge toward sheet member P from discharge port 174e of discharge duct 174. In other words, air flows through two flow paths generated by fan 176. In this way, components are shared.

[0133] Furthermore, in the static electricity removal device 150, the air flowing through the two end portions of the gap 180a does not flow through the lower side of the corotron 160 and is sucked into the suction duct 184 (refer to FIG. Figure 10 ). This can suppress leakage of the air discharged toward the sheet member P side through the corotron 160 on both sides in the depth direction.

[0134] Furthermore, in the static eliminator 150, the bottom plate 162a of the shield case 162 has through-holes 166 for air to pass through. This allows air to flow from the corotron 160 toward the sheet member P with a simpler structure than when no through-holes are formed in the bottom plate of the shield case.

[0135] Furthermore, in the static electricity removal device 150, the flow path area of ​​the discharge duct 174 and the opening area of ​​the through hole 166 are determined so that the velocity of the air discharged from the discharge port 174e of the discharge duct 174 toward the sheet member P is faster than the velocity of the air discharged from the corotron 160 toward the sheet member P. Thus, compared to a case where the velocity of the air discharged from the discharge port 174e of the discharge duct 174 toward the sheet member P is slower than the velocity of the air discharged from the corotron toward the sheet member P, the air discharged from the corotron 160 toward the sheet member P is suppressed from flowing upstream in the sheet conveyance direction.

[0136] Furthermore, in the image forming apparatus 10 , compared to the case where the static electricity removal device 250 according to the comparative embodiment is provided, stagnation of the ozone-containing air inside the apparatus main body 10 a can be suppressed.

[0137] <Second embodiment>

[0138] according to Figure 13An example of a static elimination device and an image forming apparatus according to a second embodiment of the present invention will be described. The second embodiment will be described mainly with respect to portions that differ from the first embodiment.

[0139] (Structure of the static electricity removal device 350)

[0140] like Figure 13 As shown, the static electricity removal device 350 according to the second embodiment includes a corotron 160 for removing static electricity from a charged sheet member P by corona discharge, and a recovery unit 370 for recovering ozone generated by the corona discharge.

[0141] The collecting unit 370 includes a discharge unit 372 that discharges air toward the sheet member P conveyed through the inside of the corotron 160 , and a suction unit 182 that sucks the air discharged toward the sheet member P. Air is an example of gas.

[0142] like Figure 13 As shown, the discharge unit 372 includes a discharge duct 374 and a fan 176 that blows (discharges) air toward the sheet member P conveyed through the discharge duct 374. Furthermore, the discharge unit 372 includes a guide member 378 attached to the lower end edge of the discharge duct 374 on the upstream side in the sheet conveying direction. The guide member 378 is an example of a suppressing member.

[0143] The discharge duct 374 is box-shaped, open on the discharge channel 42 side, and extends in the depth direction. Furthermore, the discharge duct 374 includes a top plate 374a, with its thickness oriented vertically, a front plate 374b, with its thickness oriented widthwise, and a back plate 174c, with its thickness oriented widthwise and positioned downstream of the front plate 374b in the sheet conveyance direction. Furthermore, the discharge duct 374 includes a pair of side plates (not shown) with their thickness oriented depthwise. No gap is provided between the front plate 374b and the shielding case 162.

[0144] The guide member 378 extends in the depth direction and has an L-shaped cross-section. Specifically, the lower end portion 380 of the guide member 378 extends downstream in the sheet conveying direction, and the upstream end 380a of the lower end portion 380 in the sheet conveying direction is located higher than the downstream end 380b of the lower end portion 380 in the sheet conveying direction. This prevents the ozone-containing air discharged toward the sheet member P from flowing upstream in the sheet conveying direction.

[0145] (Function of the static electricity removal device 350)

[0146] In the static electricity removal device 350, as Figure 13As shown, the operating fan 176 causes the air in the discharge duct 374 to flow toward the sheet member P. The air flowing toward the sheet member P passes through the through-holes 166 formed in the bottom plate 162a of the shield case 162, flows through the interior of the shield case 162, and is discharged toward the sheet member P. In this manner, the ozone-containing air generated by the corona discharge is discharged toward the sheet member P.

[0147] The ozone-containing air discharged toward the sheet member P is restrained from flowing upstream in the sheet conveying direction by the guide member 378 and flows downstream in the sheet conveying direction.

[0148] Furthermore, while a specific embodiment of the present invention has been described in detail, the present invention is not limited to this embodiment and various other embodiments can be employed within the scope of the present invention, as will be apparent to those skilled in the art. For example, in the above-described embodiment, static eliminators 150 and 350 are used in image forming apparatus 10. However, static eliminators can also be used in a post-processing device connected to the image forming apparatus, for example.

[0149] Furthermore, in the above embodiment, the corotron 160 is used for description, but any corona discharge electrode may be used, and for example, a scorotron may be used.

[0150] Furthermore, in the above embodiment, the air flows along the sheet member P from upstream to downstream in the sheet conveying direction, but the air may also flow from downstream to upstream. In this case, the effect produced by the air flowing from upstream to downstream is not produced.

[0151] Furthermore, in the first embodiment described above, air flowing toward the sheet member P by the operating fan 176 flows through a flow path for discharging toward the sheet member P through the through-hole 166 formed in the bottom plate 162a of the shield case 162, and a flow path for discharging toward the sheet member P from the discharge port 174e of the discharge duct 174. In other words, the air flows through the two flow paths by the fan 176. However, separate fans may be provided for the respective flow paths. In this case, the effects of sharing the fans are not achieved. (1)

[0153] A static electricity removal device comprising:

[0154] a corona discharge electrode facing the conveyed recording medium and extending in a direction intersecting the conveying direction of the recording medium;

[0155] an air flow generating device for causing the gas around the corona discharge electrode to flow toward the recording medium; and

[0156] The suction duct is arranged on the upstream side or the downstream side of the corona discharge electrode in the conveying direction, extends in the intersecting direction, and sucks the gas flowing toward the recording medium through the airflow generating device. (2)

[0158] The static electricity removal device according to (1), wherein

[0159] The suction duct is arranged on the downstream side of the corona discharge electrode in the conveying direction,

[0160] A suppression member is provided upstream of the corona discharge electrode in the conveying direction. The suppression member extends in the intersecting direction and suppresses the gas flowing toward the recording medium from flowing upstream of the corona discharge electrode in the conveying direction. (3)

[0162] The static electricity removal device according to (2), wherein

[0163] The suppression member includes a discharge duct extending in the intersecting direction and discharging gas toward the recording medium on the upstream side of the corona discharge electrode in the conveying direction. (4)

[0165] The static electricity removal device according to (3), wherein

[0166] The airflow generating device discharges gas from the discharge conduit. (5)

[0168] The static electricity removal device according to (3) or (4), wherein

[0169] The discharge duct and the suction duct extend along the intersecting direction and protrude relative to the corona discharge electrode on both sides in the intersecting direction. (6)

[0171] The static electricity removal device according to any one of (1) to (5), wherein

[0172] The corona discharge electrode comprises: a box-shaped shielding shell, which opens toward the recording medium and extends in the intersecting direction; and a discharge wire, which is arranged inside the shielding shell and extends in the intersecting direction.

[0173] A through hole is formed in the bottom plate of the shield case, through which gas passes by utilizing the flow of gas generated by the airflow generating device. (7)

[0175] The static electricity removal device according to (6), wherein

[0176] The suction duct is arranged on the downstream side of the corona discharge electrode in the conveying direction,

[0177] The static electricity removal device is provided with a discharge duct extending in the intersecting direction and discharging gas toward the recording medium on the upstream side of the corona discharge electrode in the conveying direction by the flow of gas generated by the airflow generating device.

[0178] The flow path area of ​​the discharge conduit and the opening area of ​​the through hole are determined so that the speed of the gas discharged from the discharge conduit toward the upstream side of the corona discharge electrode is faster than the speed of the gas from the corona discharge electrode toward the recording medium. (8)

[0180] An image forming apparatus comprising:

[0181] a transmission unit for transmitting recording media;

[0182] an image forming unit that forms an image on the recording medium transported by the transport unit; and

[0183] The static eliminating device according to any one of (1) to (7) eliminates static electricity from a charged recording medium being conveyed while forming an image.

[0184] Compared to the case where ozone-containing gas is discharged only from both ends of the recording medium in the cross direction intersecting the conveying direction of the recording medium, the static electricity removal device involved in (1) can suppress the ozone-containing gas generated in the central portion of the corona discharge electrode extending in the cross direction from stagnation on the surface of the recording medium.

[0185] Compared to the case where the gas flow is generated from the downstream side to the upstream side in the conveying direction, the static electricity removal device according to (2) can suppress an increase in the conveying resistance applied to the recording medium.

[0186] Compared to the case where a resin plate is used to suppress the flow of gas to the upstream side, the static electricity removal device according to (3) can suppress the recording medium being transported from being damaged by hitting the resin plate.

[0187] Compared to the case where different airflow generating devices are used when discharging gas from the discharge duct and when flowing the gas with a high ozone concentration around the corona discharge electrode toward the recording medium, the static electricity removal device according to (4) can reduce the number of components.

[0188] Compared to the case where the corona discharge electrodes on both sides of the cross direction protrude relative to the discharge duct and the suction duct, the static electricity removal device involved in (5) can suppress ozone leakage in the cross direction.

[0189] Compared to the case where no through-hole is formed in the bottom plate of the shield case, in the static electricity removal device according to (6), the gas with a high ozone concentration around the corona discharge electrode flows toward the recording medium with a simple structure.

[0190] Compared to a case where the speed of the gas discharged from the discharge conduit toward the recording medium is slower than the speed of the gas flowing from the corona discharge electrode toward the recording medium, the static electricity removal device involved in (7) can suppress the gas flowing from the corona discharge electrode toward the recording medium from flowing toward the upstream side of the conveying direction of the recording medium.

[0191] Compared to an image forming apparatus having a static eliminator that discharges ozone-containing gas only from both ends of the recording medium in a direction intersecting the conveying direction of the recording medium, the image forming apparatus according to (8) can suppress stagnation of ozone-containing gas inside the apparatus.

[0192] The above-described embodiments of the present invention are provided for the purpose of illustration and explanation. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed embodiments. It is obvious that various modifications and variations are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily explain the principles of the present invention and its application. Thus, other technical personnel in this field can understand the present invention through various modifications optimized for specific uses of the assumed various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A static electricity removal device comprising: a corona discharge electrode facing the conveyed recording medium and extending in a direction intersecting the conveying direction of the recording medium; an air flow generating device for causing the gas around the corona discharge electrode to flow toward the recording medium; and The suction duct is arranged on the upstream side or the downstream side of the corona discharge electrode in the conveying direction, extends in the intersecting direction, and sucks the gas flowing toward the recording medium through the airflow generating device.

2. The static electricity removal device according to claim 1, wherein: The suction duct is arranged on the downstream side of the corona discharge electrode in the conveying direction, A suppression member is provided upstream of the corona discharge electrode in the conveying direction. The suppression member extends in the intersecting direction and suppresses the gas flowing toward the recording medium from flowing upstream of the corona discharge electrode in the conveying direction.

3. The static electricity removal device according to claim 2, wherein: The suppression member includes a discharge duct extending in the intersecting direction and discharging gas toward the recording medium on the upstream side of the corona discharge electrode in the conveying direction.

4. The static electricity removal device according to claim 3, wherein: The airflow generating device discharges gas from the discharge conduit.

5. The static electricity removal device according to claim 3 or 4, wherein: The discharge duct and the suction duct extend along the intersecting direction and protrude relative to the corona discharge electrode on both sides of the intersecting direction.

6. The static electricity removal device according to any one of claims 1 to 5, wherein: The corona discharge electrode includes: a box-shaped shielding shell that opens toward the recording medium and extends along the intersecting direction; and a discharge wire that is disposed inside the shielding shell and extends along the intersecting direction. A through hole is formed in the bottom plate of the shield case, through which gas passes by utilizing the flow of gas generated by the airflow generating device.

7. The static electricity removal device according to claim 6, wherein: The suction duct is arranged on the downstream side of the corona discharge electrode in the conveying direction, The static electricity removal device is provided with a discharge duct extending in the intersecting direction and discharging gas toward the recording medium on the upstream side of the corona discharge electrode in the conveying direction by the flow of gas generated by the airflow generating device. The flow path area of ​​the discharge conduit and the opening area of ​​the through hole are determined so that the speed of the gas discharged from the discharge conduit toward the upstream side of the corona discharge electrode is faster than the speed of the gas from the corona discharge electrode toward the recording medium.

8. An image forming apparatus comprising: a transmission unit for transmitting recording media; an image forming unit that forms an image on the recording medium transported by the transport unit; and The static eliminating device according to any one of claims 1 to 7 eliminates static electricity from a charged recording medium being conveyed while forming an image.

Images