JP2013057882A - Cleaning device and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device capable of suppressing temperature elevation in the cleaning device and inhibiting problems such as toner sticking caused by temperature elevation, and to provide an image forming apparatus using the device.SOLUTION: A cleaning device 17 includes: a cleaning blade 18 for removing a residual toner on an intermediate transfer belt 20 from the intermediate transfer belt 20; a casing 60 for housing the removed toner and having a toner discharge conveyance path 61 for discharging the housed toner to the outside of the device; a conveyance screw 62 for conveying the toner in the toner discharge conveyance path 61; and a duct 63 having a cooling or heat radiation effect on the casing 60. The toner discharge conveyance path 61 is constituted with two layers of a casing inner layer 64 opposing to the conveyance screw 62 and a casing outer layer 65 formed outside the casing inner layer 64; and the casing inner layer 64 is cooled by the duct 63.

Description

  The present invention relates to a cleaning device that removes residual toner on the surface of an image carrier from the image carrier and collects the toner, and an image forming apparatus using the same.

  In recent years, in an image forming apparatus using an electrophotographic method, there is a tendency to reduce the particle size of toner for the purpose of improving image quality, and the tendency to lower the melting point of toner for the purpose of improving image printing productivity. The fluidity of the toner is poor. On the other hand, since there are many heat sources such as a fixing device and various motors in the image forming apparatus, the temperature is likely to rise compared to the outside air temperature, and heat is transmitted to the cleaning apparatus that collects residual toner. Is likely to rise. Therefore, in the toner discharge conveyance path provided in the cleaning device for discharging the toner out of the device, problems such as toner conveyance failure due to temperature rise and toner fixation due to conveyance failure are likely to occur.

  Therefore, the temperature rise of the cleaning device is suppressed by taking outside air into the image forming apparatus with an exhaust fan and passing a duct or a cooling device at or near the position where it contacts the casing of the cleaning device. ing. Patent Document 1 proposes an image forming apparatus in which a heat radiating sheet is attached to an outer wall of a casing of a cleaning device.

  However, the heat reduction effect on the toner discharge conveyance path differs depending on the configuration around the toner discharge conveyance path even if a duct is passed through or a cooling device is disposed at or near the casing of the cleaning device. Further, it is considered that the heat reduction effect is reduced if the ambient temperature around the cleaning device is increased only by attaching the heat radiation sheet to the casing of the cleaning device.

  The present invention has been made in view of the above problems, and an object of the present invention is to suppress a temperature rise in the cleaning device and to use a cleaning device that can suppress problems such as toner fixation due to the temperature rise. An image forming apparatus is provided.

  In order to solve the above-mentioned problems, the invention of claim 1 is characterized in that a removal means for removing residual toner on the surface of the image carrier from the image carrier, a removed toner is accommodated, and the accommodated toner is discharged out of the apparatus. A cleaning device having a casing in which a toner discharge conveyance path for forming a toner is formed, a toner conveyance member that conveys toner in the toner discharge conveyance path, and a cooling means that has a cooling action or a heat radiation action on the casing In addition, at least a portion of the casing that forms the toner discharge conveyance path is configured by two layers of a casing inner layer facing the toner conveying member and a casing outer layer formed outside the casing inner layer. The inner layer is cooled by the cooling means.

  INDUSTRIAL APPLICABILITY The present invention has an excellent effect that it is possible to provide a cleaning device that can suppress an increase in temperature in the cleaning device and can suppress problems such as toner fixation due to the temperature increase, and an image forming apparatus using the same. .

1 is a configuration diagram illustrating an example of an image forming apparatus according to an embodiment. FIG. 2 is a schematic configuration diagram illustrating a configuration of a cleaning device of the image forming apparatus. The perspective view which shows the partial structure of the cleaning apparatus. Sectional drawing which shows the structure which installed the duct in the cleaning apparatus. Sectional drawing which shows the structure which installed the cooling device of the cleaning apparatus.

  Hereinafter, an embodiment of an image forming apparatus to which the present invention is applied will be described. FIG. 1 is a configuration diagram illustrating an example of an image forming apparatus according to the present embodiment. The image forming apparatus includes a copying machine main body 100, a paper feed table 200 on which the copying machine main body 100 is placed, a scanner 300 attached on the copying machine main body 100, and an automatic document attached on the scanner 300. It is mainly composed of a transfer device (ADF) 400.

  The scanner 300 is placed on the contact glass 32 as the first traveling body 33 equipped with a document illumination light source or mirror and the second traveling body 34 equipped with a plurality of reflecting mirrors reciprocate. Scanning of a document (not shown) is performed. The scanning light sent out from the second traveling body 34 is condensed by the imaging lens 35 on the imaging surface of the reading sensor 36 disposed behind it, and then read as an image signal by the reading sensor 36.

  A tandem type image forming apparatus 10 is disposed in the copying machine main body 100. The tandem-type image forming apparatus 10 includes image forming units 11Y, 11C, 11M, and 11K corresponding to yellow, cyan, magenta, and black toners. Each image forming unit 11 is provided with photosensitive drums 12Y, 12C, 12M and 12K. Around each photosensitive drum 12, a charging device that uniformly charges the photosensitive drum, a developing device that develops a latent image on the photosensitive drum, a photosensitive member cleaning device that removes residual toner on the photosensitive drum, and the like Each means for executing the electrophotographic process is arranged.

  Above the tandem type image forming apparatus 10, there is provided an exposure device 21 that forms a latent image by exposing the photosensitive drum 12 with laser light or LED light based on image information.

  An intermediate transfer belt 20 that is an image carrier made of an endless belt member is disposed at a lower position facing the photosensitive drum 12 of the tandem type image forming apparatus 10. The intermediate transfer belt 20 is supported by support rollers 14, 15 and 16. A primary transfer roller 13 for transferring the toner images of the respective colors formed on the photosensitive drum 12 to the intermediate transfer belt 20 is disposed at a position adjacent to the photosensitive drum 12 via the intermediate transfer belt 20. Further, the intermediate transfer belt 20 is provided with a cleaning device 17 described later for removing toner remaining on the surface thereof.

  Under the intermediate transfer belt 20, secondary transfer is performed in which the toner images formed on the surface of the intermediate transfer belt 20 are collectively transferred onto a sheet as a transfer medium conveyed from the paper feed tray 44 of the paper feed table 200. A roller 22 is arranged. The secondary transfer roller 22 contacts the support roller 16 via the intermediate transfer belt 20, and transfers the toner image on the intermediate transfer belt 20 to a sheet (not shown). Hereinafter, the support roller 16 is referred to as a secondary transfer backup roller 16.

  At a position adjacent to the secondary transfer roller 22, a conveyance belt 24 stretched around the two rollers 23 is provided to convey the secondary transferred sheet. A fixing device 25 is provided at a position adjacent to the conveyance belt 24. The fixing device 25 fixes the image on the sheet conveyed by the conveyance belt 24. The fixing device 28 mainly includes a fixing belt 26 that is an endless belt and a pressure roller 27 that is pressed against the fixing belt 26. Below the secondary transfer roller 22 and the fixing device 28, a sheet reversing device 28 for reversing the sheet is disposed. The sheet reversing device 28 reverses the sheet to record images on both sides of the sheet.

  Next, the operation of the image forming apparatus having the above configuration will be described. First, a document is set on the document table 30 of the automatic document feeder 400 shown in FIG. 1, or the automatic document feeder 400 is opened and a document is set on the contact glass 32 of the scanner 300. close up. In this state, when a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the other contact glass 32. When this occurs, the scanner 300 is immediately driven to cause the first traveling body 33 and the second traveling body 34 to travel. The first traveling body 33 emits light from the light source and receives reflected light from the document surface, reflects the reflected light toward the second traveling body 34, and further reflects the reflected light by the mirror of the second traveling body 34. Then, the light enters the reading sensor 36 through the imaging lens 35, and the reading sensor 36 reads the content of the document.

  Further, by pushing a start switch of the apparatus, a drive motor (not shown) is driven to rotate one of the support rollers 14, 15, and 16 and the other two support rollers are driven to rotate, thereby performing intermediate transfer. The belt 20 is rotated. At the same time, in each image forming unit 10, the photosensitive drum 12 is uniformly charged by the charging device, and then charged by irradiating the writing light L from the exposure device 21 with a laser, LED, or the like according to the reading content of the scanner 300. An electrostatic latent image is formed on each photosensitive drum 12. Toner is supplied from the developing device to the photosensitive drum 12 on which the electrostatic latent image is formed, and the electrostatic latent image is visualized, and black, yellow, magenta, and cyan single-color images are respectively formed on the photosensitive drums 12. Form. A single color image is sequentially primary transferred by the primary transfer roller 13 so as to overlap the intermediate transfer belt 20, and a composite color image is formed on the intermediate transfer belt 20. Residual toner is removed from the surface of the photoconductive drum 12 after image transfer by a photoconductor cleaning device, and the charge is removed by a static eliminator to prepare for image formation again.

  By pressing the start switch, one of the paper feed rollers 42 of the paper feed table 200 is selected and rotated, and the sheet is fed out from one of the paper feed cassettes 44 provided in multiple stages in the paper bank 43, and the separation roller 45. Then, the sheets are separated one by one and inserted into the sheet feeding path 46, conveyed by the conveying roller 47, guided to the sheet feeding path 48 in the copying machine main body 100, and abutted against the registration roller 49 and stopped. On the other hand, when the sheet is manually fed, the sheet feeding roller 50 is rotated to feed the sheet on the manual tray 51, and the sheet is separated one by one by the separation roller 52 and inserted into the manual sheet feeding path 53. Similarly, the registration roller Stop at 49. Next, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer belt 20, the sheet is fed between the intermediate transfer belt 20 and the secondary transfer device 19, and transferred by the secondary transfer device 19. Transfer the color image onto the sheet.

  The sheet carrying the unfixed toner image that has passed through the secondary transfer roller 22 is conveyed to the fixing device 28, and heat and pressure are applied by the fixing device 28 to fix the transferred image as a permanent image. The sheet after image fixing is switched by the switching claw 55 and discharged by the discharge roller 56 and stacked on the paper discharge tray 57, or switched by the switching claw 55 and introduced into the sheet reversing device 28, where it is reversed. The image is again guided to the transfer position, an image is recorded on the back side, and then discharged onto the discharge tray 57 by the discharge roller 56. At this time, residual toner remaining on the intermediate transfer belt 20 after image transfer is removed by the cleaning device 17 to prepare for re-image formation by the tandem image forming device 20.

Here, the registration roller 49 is generally used while being grounded. This is because the intermediate transfer method generally does not require the transfer of paper dust because the paper dust of the sheet is difficult to move to the photosensitive drum 12. However, it is also possible to apply a bias to the registration roller 49 in order to remove paper dust from the sheet. For example, a bias is applied using a conductive rubber roller. The surface is a conductive NBR rubber having a diameter of 18 mm and a thickness of 1 mm. The electrical resistance is about 10 ⁹ Ω · cm, which is the volume resistance of the rubber material. The applied voltage is about −800 V applied to the toner transfer side (front side), and about +200 V is applied to the back side of the paper. . Further, a DC bias is applied as the applied voltage, but this may be an AC voltage having a DC offset component in order to more uniformly charge the sheet. Thus, the sheet surface after passing through the registration roller 49 to which a bias is applied is slightly charged on the negative side. Therefore, in the transfer from the intermediate transfer belt 20 to the sheet, there are cases where the transfer conditions are changed and the transfer conditions are changed as compared with the case where no voltage is applied to the registration roller 49.

  The cleaning device 17 is generally performed by bringing a rubber blade represented by polyurethane rubber into contact with the belt. This is because an inexpensive and reliable cleaning property can be expected. However, in this blade cleaning method, when paper dust is caught between the blade and the belt, a cleaning failure occurs. In the present embodiment, since the sheet is in direct contact with the intermediate transfer belt 20, entry of paper powder is inevitable. Therefore, in the present embodiment, a cleaning device 17 described later is employed in order to prevent the influence of paper dust and to ensure cleaning properties.

  FIG. 2 is a schematic configuration diagram showing the configuration of the cleaning device. The cleaning device 17 shown in FIG. 2 is provided at a position facing one counter roller 67 among the rollers that stretch the intermediate transfer belt 20. In this cleaning device 17, a cleaning blade 18 that abuts against the opposing roller 67 via the intermediate transfer belt 20 to remove residual toner, and the intermediate transfer belt 20 is moved upstream of the cleaning blade 18 in the intermediate transfer belt moving direction. And a brush roller 19 serving as a paper dust removing member that contacts the opposing roller 67 and removes the paper dust. The installation of the brush roller 19 suppresses the deterioration of the degree of aggregation of toner due to the mixing of paper dust, and has an effect of suppressing a problem of toner fixation as described later. In this case, the brush roller 19 may be rotated together with the intermediate transfer belt 20, but it is desirable that the brush roller 19 is driven. Here, PET resin is used as the material of the brush hair. As described above, by placing the brush roller 19 on the upstream side of the cleaning blade 18, it is possible to reduce the cleaning property due to the paper dust being constantly caught between the cleaning blades 18 with a simple configuration without impairing image formation. Can be prevented. Further, since the paper dust removing member is formed by the brush roller 19, toner can be removed at the same time as the paper dust removal, and the effect of reducing the burden on the cleaning blade 18 and extending the life of the cleaning blade 18 is also achieved. I can expect.

  FIG. 3 is a perspective view showing a partial configuration near the bottom of the cleaning device 17. FIG. 4 is a cross-sectional view showing a configuration in which a duct is installed in the cleaning device. As shown in FIGS. 3 and 4, the cleaning device 17 stores the toner removed by the cleaning blade 18 in the casing 60. At the bottom of the casing 60, a toner discharge conveyance path 61 for conveying the toner to be stored to a waste toner tank (not shown) outside the cleaning device 17 extends along the axial direction (hereinafter referred to as the longitudinal direction) of the counter roller 67. Is formed. In the toner discharge conveyance path 61, a conveyance screw 62 for conveying the removed toner to the outside of the apparatus is installed.

  A duct 63 serving as a cooling means is provided along the outer wall of the casing 60 of the cleaning device 17 where the toner discharge conveyance path 61 is formed. The duct 63 is a rectangular tube, and includes a not-shown intake port for taking in outside air and an exhaust port for discharging the taken-in outside air, and cools the periphery of the duct 63 by passing outside air through the tube. Have the effect of

  Here, the toner discharge conveyance path 61 of the casing 60 is formed in two layers: a casing inner layer 64 that is a surface facing the conveyance screw 62, and a casing outer layer 65 formed outside the casing inner layer 64. It consists of The casing inner layer 64 has a surface facing the conveying screw 62 formed in an arc shape along the rotation trajectory of the conveying screw 62, and a surface facing the duct 63 side extends as a part of the wall surface of the duct 63. Exist. The casing inner layer 64 is directly cooled by air serving as a cooling portion passing through the duct 63. On the other hand, the casing outer layer is formed so as to cover an arcuate surface facing the conveying screw 62 of the casing inner layer 64 and to occupy the bottom of the casing 60. The casing outer layer 65 covers the bottom of the casing 60 (including the casing inner layer 64), and thus has a heat insulating effect that blocks heat outside the casing 60 from moving into the casing 60.

  In the toner discharge conveyance path 61 configured as described above, the casing inner layer 64 is directly cooled by the outside air flowing in the duct 63 and has a cooling effect on the toner discharge conveyance path. Thereby, the toner temperature accumulated in the toner discharge conveyance path 61 and the temperature in the casing 60 can be reduced. On the other hand, the casing outer layer 65 has a heat insulating effect that blocks heat outside the casing 60 from moving into the casing 60. As a result, even if the temperature inside the machine outside the casing 60 rises, the inside of the casing 60 (toner discharge conveyance path 61) is hardly affected, and the rise in the machine temperature can be suppressed. In this way, the portion constituting the toner discharge conveyance path 61 of the casing 60 has a two-layer configuration of the casing inner layer 64 and the casing outer layer 65, and the functions of the cooling function and the heat insulating function are separated. As a result, an increase in the toner temperature in the casing 60 (toner discharge conveyance path 61) can be suppressed, and the occurrence of malfunction such as toner fixation due to an increase in the toner temperature in the casing 60 can be suppressed.

  In order to exhibit the cooling effect and the heat insulating effect described above, it is preferable to use materials having different thermal conductivities for the casing inner layer 64 and the casing outer layer 65. In particular, the casing inner layer 64 is preferably made of a material having a large heat traditional rate such as a metal material such as aluminum. The casing outer layer 65 is preferably made of a material having a low thermal conductivity such as a resin material.

  Further, the casing inner layer 64 is preferably grounded using a conductive material because the toner comes into contact therewith and there is also friction with the conveying screw 62. As a result, charging of the casing inner layer 64 can be suppressed, toner transportability can be improved, and toner fixing problems can be suppressed.

  Moreover, it is good to give a low friction process to the surface which rubs with the conveyance screw 62 of the casing inner side layer 64. FIG. Thereby, the adhesion force between the toner conveyance path 61 (the casing inner layer 64) and the toner can be reduced, and the problem of toner fixation can be prevented.

  The cooling means is not limited to the duct 63, and any cooling means such as a cooling device using liquid cooling, a heater tank, or the like may be used. FIG. 5 is a cross-sectional view showing a configuration in which a cooling device by liquid cooling is installed in the cleaning device. For example, the cooling device 66 by liquid cooling shown in FIG. 5 is disposed along the portion where the toner discharge conveyance path 61 of the casing 60 is formed, and directly cools the end portion of the casing inner layer 64. Thereby, as described above, an increase in the toner temperature in the casing 60 (toner discharge conveyance path 61) can be suppressed, and the occurrence of malfunction such as toner fixing due to the increase in the toner temperature in the casing 60 can be suppressed.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
Removal means such as a cleaning blade 18 for removing residual toner on the surface of the image carrier such as the intermediate transfer belt 20 from the image carrier, and toner for containing the removed toner and discharging the contained toner out of the apparatus A casing such as a casing 60 in which a toner discharge conveyance path such as a discharge conveyance path 61 is formed, a toner conveyance member such as a conveyance screw 62 that conveys toner in the toner discharge conveyance path, and a cooling or heat dissipation action on the casing. In a cleaning device such as a cleaning device 17 having a cooling means such as a duct 63 and a cooling device 66, a toner discharge transport path is formed on the casing inner layer facing the toner transport path member and on the outer side of the casing inner layer. The casing inner layer is cooled by the cooling means. According to this, the casing inner layer has a cooling effect on the toner in the toner discharge conveyance path, and the casing outer layer has a heat insulating effect that blocks the temperature outside the casing from being transmitted into the casing. Therefore, even if the temperature outside the casing becomes high, the toner temperature hardly rises in the toner discharge conveyance path, and it is possible to suppress problems such as toner fixation due to the toner temperature rise.
(Aspect B)
In the cleaning device of (Aspect A), the casing inner layer is partially exposed from the casing outer layer, and is cooled by being in contact with a cooling unit having a cooling action or a heat radiation action of the cooling means. According to this, the casing inner layer can be directly cooled by the cooling part, and the portion other than the cooling action is covered with the casing outer layer and the heat from outside the casing is blocked.
(Aspect C)
In the cleaning device of (Aspect A) or (Aspect B), the casing inner layer and the casing outer layer are made of materials having different thermal conductivities. According to this, it is possible to separate the functions of the casing inner layer and the casing outer layer.
(Aspect D)
In the cleaning device of (Aspect C), the thermal conductivity of the material constituting the casing inner layer is larger than the thermal conductivity of the material constituting the casing outer layer. According to this, the cooling effect which a casing inner side layer has, and the heat insulation effect which a casing outer side layer has can be exhibited.
(Aspect E)
(Aspect A) (Aspect B) In the cleaning device of Aspect C or Aspect D, the casing inner layer is made of a conductive material and grounded. According to this, charging of the casing inner layer is suppressed, and toner sticking in the toner discharge conveyance path can be suppressed.
(Aspect F)
(Aspect A) In the cleaning device according to (Aspect B), (Aspect C), (Aspect D) or (Aspect E), the surface of the casing inner layer facing the toner conveying means is subjected to a friction reduction process. ing. According to this, the adhesion force between the casing inner layer and the toner is reduced, and toner fixation in the toner discharge conveyance path can be suppressed.
(Aspect G)
(Aspect A) In the cleaning device according to (Aspect B), (Aspect C), (Aspect D), or (Aspect E), the image carrier is an intermediate transfer member such as the intermediate transfer belt 20. The residual toner removed from the intermediate transfer member is liable to be mixed with foreign matters such as lubricants and paper dust, and the degree of toner aggregation is likely to deteriorate, and toner sticking is likely to occur. However, in (Aspect F), it is possible to suppress an increase in the toner temperature in the casing, and thus it is possible to suppress the occurrence of malfunction such as toner fixation.
(Aspect H)
An image forming unit such as an image forming unit 11 that forms a toner image on an image carrier such as an intermediate transfer belt 20, a secondary transfer roller 22 that transfers a toner image on the image carrier to a transfer medium such as a sheet, and the like. In the image forming apparatus including the transfer means and the cleaning means such as the cleaning device 17 that removes the toner remaining on the image carrier after the transfer by the transfer means, the cleaning means includes (Aspect A) (Aspect B), The cleaning device according to (Aspect C), (Aspect D), (Aspect E), (Aspect F) or (Aspect G) is used. According to this, by mounting the above-described cleaning device, it is possible to suppress malfunctions such as toner fixation in the cleaning device.

17 Cleaning device 20 Intermediate transfer belt 60 Casing 61 Toner discharge conveying path 62 Conveying screw 63 Duct 64 Casing inner layer 65 Casing outer layer 66 Cooling device

Japanese Patent Laying-Open No. 2005-164771

Claims (8)

Removing means for removing residual toner on the surface of the image carrier from the image carrier;
A casing in which a toner discharge conveyance path for storing the removed toner and discharging the stored toner to the outside of the apparatus is formed;
A toner conveying member for conveying toner in the toner discharge conveying path;
In the cleaning apparatus having a cooling means having a cooling action or a heat radiation action on the casing,
At least a portion of the casing that forms the toner discharge conveyance path is configured by two layers of a casing inner layer facing the toner conveying member and a casing outer layer formed outside the casing inner layer. A cleaning device, wherein the layer is cooled by the cooling means. The cleaning device according to claim 1.
The cleaning device according to claim 1, wherein the casing inner layer is partially exposed from the casing outer layer and is cooled by being in contact with a cooling portion having a cooling action or a heat dissipation action of the cooling means. The cleaning device according to claim 1 or 2,
The cleaning device according to claim 1, wherein the casing inner layer and the casing outer layer are made of materials having different thermal conductivities. The cleaning device according to claim 3.
The cleaning apparatus according to claim 1, wherein a thermal conductivity of a material constituting the casing inner layer is larger than a thermal conductivity of a material constituting the casing outer layer. The cleaning device according to claim 1, 2, 3 or 4.
The casing inner layer is made of a conductive material and is grounded. The cleaning device according to claim 1, 2, 3, 4 or 5.
A cleaning device, wherein a surface of the casing inner layer facing the toner conveying means is subjected to a friction reducing process. The cleaning device according to claim 1, 2, 3, 4, 5 or 6.
A cleaning device, wherein the image carrier is an intermediate transfer member. Image forming means for forming a toner image on the image carrier, transfer means for transferring the toner image on the image carrier to a transfer medium, and removing toner remaining on the image carrier after transfer by the transfer means In an image forming apparatus comprising a cleaning unit
8. An image forming apparatus using the cleaning device according to claim 1, 2, 3, 4, 5, 6 or 7.

Images