JP2013182080A - Cleaning device and image formation apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device which can prevent toner from being deposited on the inner wall of a housing, and an image formation apparatus including the same.SOLUTION: A screw brush 71 that conveys the toner removed from the surface of a photoreceptor drum 22 with a cleaning blade 72 to a toner recovery unit, is arranged to contact with an inner wall face of a housing 70.

Description

  The present invention relates to a cleaning device in an image forming apparatus, and more particularly to a cleaning device adopting a blade cleaning method and an image forming apparatus including the same.

  In the blade cleaning method, toner remaining on the surface of the photosensitive drum after the toner image is transferred is removed by a cleaning blade, and the removed toner is conveyed to a toner recovery bottle. In this type of apparatus, there is a type in which a screw brush is provided upstream of the cleaning blade in the rotation direction of the photosensitive drum.

  There are various purposes for which the screw brush is provided. For example, in the cleaning device disclosed in Patent Document 1, in order to suppress noise caused by friction between the cleaning blade and the photosensitive drum, deterioration of the photosensitive drum, and the like, the toner is applied to an area where the toner does not adhere to the surface of the photosensitive drum. A screw brush (silical brush) is provided for the purpose of conveyance.

  Further, in the cleaning device of Patent Document 2, a screw brush (spiral fur brush) that collects toner at the axial center of the surface of the photosensitive drum in order to suppress toner scattering from the axial end of the photosensitive drum having a weak seal. ) Is provided.

  In the cleaning device of Patent Document 3, a screw brush (cleaning brush) having both a function of polishing the surface of the photosensitive drum in contact with the surface of the photosensitive drum and a conveying function of conveying the removed toner to the toner recovery bottle is provided. It has been.

JP 2010-117521 A Japanese Patent Application Laid-Open No. 07-146632 JP 2003-287799 A

  However, in the configuration of the cleaning device disclosed in Patent Documents 1 to 3, no attention is paid to the adhesion of the toner to the inner wall of the housing. Therefore, the toner transportability is hindered by the fixed toner, and in the worst case, the toner may overflow from the cleaning device.

  When the toner adheres to the inner wall of the housing, a load is applied to the conveying member that conveys the toner to the toner recovery bottle, and the torque of the conveying member increases. As a result, the toner conveyance performance is affected. In the worst case, the conveyance member stops and the toner cannot be conveyed, and the toner accumulated inside the housing overflows outside the apparatus.

  When the toner adheres to the inner wall of the housing, the tip of the screw brush is heated by friction with the adhered toner, and the temperature inside the image forming apparatus increases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning device capable of preventing toner from adhering to the inner wall of a housing and an image forming apparatus including the same.

  As a result of intensive studies to achieve the above object, the applicant of the present application has tried to separately provide a screw brush that is brought into contact with the inner wall of the housing. However, the inner wall portion where the toner may adhere is a bottom portion of the housing where the removed toner is accumulated, and is an area where a conveying member for conveying the removed toner to the toner collection bottle is provided. Therefore, the applicant of the present application has found that the inner wall of the housing is rubbed with a screw brush that forms a conveying member, and has reached the present invention.

  In order to solve the above-described problems, the cleaning device of the present invention includes a cleaning blade that contacts the surface of the photosensitive drum and removes residual toner from the surface, a brush portion in which the brush hair is implanted, and a brush hair that is implanted. A non-brush portion that is not provided, and a screw brush that conveys the toner removed from the surface of the photosensitive drum by the cleaning blade to a toner recovery portion, and a housing that accommodates these, The screw brush is arranged to be in contact with the inner wall of the housing.

  According to the above configuration, the screw brush that conveys the toner removed from the surface of the photosensitive drum to the toner collecting unit rubs against the inner wall of the housing, so that the toner can be prevented from adhering to the inner wall.

  As a result, it is possible to avoid a situation in which the toner inside the housing overflows and a situation in which the temperature inside the image forming apparatus rises.

  In the cleaning device of the present invention, it is further preferable that the screw brush is arranged such that the brush hair is not in contact with the photosensitive drum. According to this, deterioration of the photosensitive drum due to contact of the screw brush can be prevented.

  The cleaning device of the present invention may further include a configuration in which the screw brush is provided such that the toner conveying capability on the downstream side is higher than the upstream side in the toner conveying direction.

  According to this, since the toner conveying capability of the screw brush is increased downstream from the upstream side in accordance with the amount of toner conveyed in the housing, the scraped toner can be efficiently conveyed to the toner collecting unit. .

  As a configuration for increasing the toner conveying ability of the screw brush on the downstream side from the upstream side, for example, the pile diameter of the brush hair is set to be thicker on the downstream side than the upstream side in the toner conveying direction. For example, the pitch of the spiral brush portion may be set higher on the downstream side than the upstream side in the conveyance direction, or the pitch of the spiral brush portion may be set larger on the downstream side than the upstream side in the toner conveyance direction.

  In the cleaning device of the present invention, the screw brush may be configured such that the brush diameter of the most upstream portion in the toner transport direction is set larger than the brush diameter of other portions.

  According to this, the most upstream side in the toner conveyance direction in which a large toner reservoir is easily formed is effectively sealed at a portion where the brush diameter is set larger than the other portions. Thereby, it is possible to effectively prevent the toner from blowing out from the gap and the lump falling to the outside of the housing.

  The present invention also includes an image forming apparatus equipped with the above-described cleaning device of the present invention.

  According to the present invention, there is an effect that it is possible to provide a cleaning device capable of preventing the toner from adhering to the inner wall of the housing and an image forming apparatus including the same.

It is sectional drawing which shows the structure of each member, such as the cleaner unit of one Embodiment of this invention, and the photoreceptor drum arrange | positioned around it. It is sectional drawing which shows the structure of the image forming apparatus with which the said cleaner unit was mounted. It is a partial cross-sectional perspective view of the principal part which shows the structure of the screw brush with which the said cleaner unit was equipped. It is explanatory drawing which shows the device given to the screw brush with which the said cleaner unit was equipped.

  Hereinafter, embodiments of the present invention will be described in detail.

  An image forming apparatus 10 according to an embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 2, the image forming apparatus 10 includes an image forming unit 11, an automatic document feeder 12, a reading unit 68, a reading unit 90, and a control unit 50, and is a composite including a document reading function and an image forming function. Machine. The image forming apparatus 10 performs multicolor and single color image forming processing on a sheet.

  The reading unit 90 has a document placing table 92 on the upper surface, and reads a document placed on the document placing table 92. A reading glass 93 is provided adjacent to the end of the document table 92.

  The automatic document feeder 12 sequentially conveys the document to a position facing the reading glass 93 and reads the document when the document passes the position facing the reading glass 93.

  The image forming unit 11 includes an exposure unit 14, an intermediate transfer belt unit 60, a fixing unit 69, image forming stations 20K to 20Y, a paper feeding unit 40, a paper discharge tray 17, and a secondary transfer unit 30, and forms an image on a sheet. Process.

  The image forming stations 20K to 20Y are arranged according to the color images of black (K), cyan (C), magenta (M), and yellow (Y), respectively, and have almost the same configuration. Each of the image forming stations 20K to 20Y forms four types of toner images corresponding to each color. In FIG. 2, only the image forming station 20K is shown with a reference numeral. Hereinafter, the image forming station 20K will be described.

  The image forming station 20K includes a photosensitive drum (rotating body) 22 and forms a toner image corresponding to a black (K) color image. In the image forming station 20 </ b> K, a charger 24, a developing device 21, an intermediate transfer roller 64, and a cleaner unit (cleaning device) 23 are arranged in this order along the rotation direction of the photosensitive drum 22.

  The charger 24 is a charger that charges the surface of the photosensitive drum 22 to a predetermined potential. The charger 24 and the developing unit 21 communicate the photosensitive drum 22 with a lower space in order to form an electrostatic latent image by irradiating the photosensitive drum 22 charged to the predetermined potential with laser light from below. It is arranged with a gap.

  The developing device 21 supplies black (K) toner to the photosensitive drum 22, and the toner is attracted to the electrostatic latent image formed on the photosensitive drum 22 to visualize the toner. The intermediate transfer roller 64 is applied with a positive polarity transfer bias of about several hundred volts. On the other hand, the toner image carried on the photosensitive drum 22 is charged with a negative polarity. As a result, the toner image is carried on the intermediate transfer belt 61.

  The intermediate transfer belt unit 60 is disposed above the photosensitive drum 22 and includes an intermediate transfer belt 61, an intermediate transfer belt driving roller 62, an intermediate transfer belt driven roller 63, an intermediate transfer belt cleaning unit 65, and the like.

  The intermediate transfer belt 61 is stretched so as to rotate the intermediate transfer belt driven roller 63, the image forming stations 20Y, 20M, 20C, and 20K, and the intermediate transfer belt driving roller 62 in a direction passing in this order. The intermediate transfer belt cleaning unit 65 collects residual toner adhering to the intermediate transfer belt 61.

  The exposure unit 14 is a laser scanning unit (LSU) provided with a laser emitting portion, a reflection mirror, and the like. The exposure unit 14 has a function of forming the electrostatic latent image corresponding to the image data on the surface thereof by exposing the charged photosensitive drum 22 according to the input image data.

  The paper feed unit 40 includes a manual feed tray 16, a paper feed cassette 15, a registration roller pair 33, a feeding mechanism 41, and the like.

  In the paper feed cassette 15, sheets used for image forming processing are stacked, and are provided below the exposure unit 14. The manual feed tray 16 is provided on the side surface of the apparatus main body, and the paper to be fed is placed in the same manner as the paper feed cassette 15. The paper discharge tray 17 is provided above the image forming unit 11 and accumulates sheets on which image forming processing has been performed by the image forming unit 11.

  The fixing unit 69 has a roller pair that sandwiches the paper that has passed through the transfer region and performs heat treatment and pressure bonding. As a result, the toner image formed on the surface of the paper is fixed. The paper that has passed through the fixing unit 69 is discharged to the paper discharge tray 17.

  The feeding mechanism 41 is provided at the end of the paper feeding cassette 15 and feeds the sheets stored in the paper feeding cassette 15 one by one to the downstream side of the transport path.

  The registration roller pair 33 temporarily holds the sheet fed from the upstream side of the conveyance path. Then, the sheet is conveyed to a transfer region between each intermediate transfer belt 61 on the upstream side and the secondary transfer unit 30 at the timing when the leading end of the toner image carried on the intermediate transfer belt 61 is aligned with the leading end of the printing position of the sheet. . Thereby, the toner image can be transferred to the paper.

  The secondary transfer unit 30 includes a pressure contact roller that is in pressure contact with the secondary transfer belt and the intermediate transfer belt 61 sandwiched between the secondary transfer belt stretched by a plurality of rollers and the intermediate transfer belt drive roller 62. Have.

  The control unit 50 controls image forming processing on a sheet in the image forming unit 11. Further, the control unit 50 controls document reading in the automatic document feeder 12 and causes image data on both sides of the document to be image-formed on a sheet.

  As shown in FIG. 1, the cleaner unit 23 is disposed upstream of the charger 24 in the rotational direction of the photosensitive drum 22. The cleaner unit 23 includes a housing 70, a screw brush 71, a cleaning blade 72, and a toner receiving sheet 73.

  The cleaning blade 72 is provided so that its tip comes into contact with the surface of the photosensitive drum 22, and scrapes off the toner remaining on the surface of the photosensitive drum 22. The toner scraped off by the cleaning blade 72 falls into the housing 70.

  A screw brush 71 is provided in the housing 70. The screw brush 71 is a conveying member having a spiral shape, and conveys the scraped toner to one end in the axial direction where a toner collection bottle (toner collection unit, not shown) is installed. The housing 70 is also provided with a brush cleaning protrusion 74 that contacts the screw brush 71 and discharges the toner held inside the screw brush 71.

  In the conventional cleaning device, the screw brush is provided for various purposes, but all of them are in contact with the photosensitive drum. On the other hand, in the cleaner unit 23 of the present embodiment, the screw brush 71 is disposed so as not to contact the photosensitive drum 22 but to contact the inner wall of the housing 70. The inner wall of the housing 70 also has a circular cross section in the XY plane from the bottom where the toner accumulates to the side wall so that the tip of the rotating screw brush 71 contacts.

  With such a configuration, in the cleaner unit 23 of the present embodiment, the toner attached to the inner wall of the housing 70 by the rotation of the screw brush 71 that conveys the scraped toner to the toner recovery bottle is effective. Thus, the toner can be prevented from sticking to the inner wall. Further, since the screw brush 71 does not come into contact with the photosensitive drum 22, deterioration of the photosensitive drum 22 due to contact or sliding of the screw brush 71 can be avoided.

  In the cleaner unit 23 of the present embodiment, the toner remaining on the surface of the photosensitive drum 22 is removed by the cleaning blade 72 alone, but the screw brush 71 does not contact the photosensitive drum 22. The remaining toner can be removed without any problem.

  As shown in FIG. 3, the screw brush 71 includes a brush portion 81 and a brush bristle 83 in which the tape bristle 83 is implanted and spirally wound around a metallic shaft. Is provided with a non-brush portion 82 that is not implanted. The brush bristles 83 are planted radially from the axial center, and the screw brush 71 is disposed so that the tip of the brush bristles 83 contacts the inner wall of the housing 70.

  As a material for the brush bristles 83, it is necessary to select an appropriate material and to have a certain degree of roughness on the surface thereof, which has high durability and flexibility, excellent wear resistance, and good slidability. It is preferably formed from fibers. For example, when a toner having a negatively charged polarity is used as a toner, polyester having the same charging series, or acrylic, polyethylene, celluloid, cellophane, vinyl chloride, which are negatively charged and located on the negative side of the polyester. And Teflon (registered trademark). On the other hand, when a toner having a positive charge polarity is used as the toner, it is preferable that the toner is made of nylon, rayon or the like having the same charging series.

The wire diameter of the brush hair 83 can be, for example, 15 μm to 50 μm that is generally used as a brush hair for OA equipment, printing, and papermaking, and the flocking density of the brush hair 83 is, for example, 60000 to 100000. By setting this to inch / inch ² , both toner retention and discharge are compatible. The pile length (hair length) of the brush hair 83 may be set to 5 mm, for example.

  A drive source (not shown) is provided on one end side of the screw brush 71, whereby the screw brush 71 can rotate. Further, an opening (not shown) is provided on the other end side of the cleaner unit 23, and the opening communicates with a toner collection bottle (not shown) that is removable from the cleaner unit 23. As a result, the screw brush 71 rotates to move the non-brush portion 82 formed in a spiral, and the scraped toner is guided to the toner recovery bottle.

  Furthermore, it is more preferable that the screw brush 71 is provided so that the toner conveying capability on the downstream side (side where the toner collection bottle is disposed) is higher than the upstream side in the toner conveying direction.

  In the housing 70, the toner amount increases because the toner scraped from the photosensitive drum 22 by the cleaning blade 72 is combined with the toner transported from the upstream as the toner transports in the downstream direction. Therefore, the scraped toner can be efficiently conveyed to the toner collection bottle by increasing the toner conveying capability of the screw brush 71 on the downstream side of the upstream side in accordance with the amount of toner to be conveyed. As a result, in the cleaner unit 23, toner leakage, toner scattering, and clogging of the screw brush 71 can be effectively prevented.

  For example, the following three methods 1) to 3) can be cited as methods for increasing the toner conveyance capability on the downstream side of the upstream side in the toner conveyance direction.

  1) The pile diameter of the bristle 83 in the screw brush 71 is set to be larger on the downstream side than on the upstream side in the toner conveyance direction.

  2) The density of the bristles 83 in the screw brush 71 is set higher on the downstream side than on the upstream side in the toner conveyance direction.

  3) The spiral pitch of the brush part 81 in the screw brush is set larger on the downstream side than on the upstream side in the toner conveyance direction.

  By increasing the pile diameter of the brush bristles 83, even if the flocking density is the same, the brush bristles 83 are less likely to bend, and the toner conveying capability is increased. By increasing the flocking density of the brush bristles 83, even if the pile diameter is the same, it is difficult to bend and the toner conveying capability is increased. By increasing the helical pitch of the brush part 81, the distance conveyed along the non-brush part 82 in one rotation is increased, and the toner conveying capability is increased.

  As shown in FIG. 4, the screw brush 71 may be divided into an upstream side and a downstream side, and any one of the above-described methods 1) to 3) may be applied, or two or more methods may be combined. You may give it. Moreover, the screw brush 71 may be applied from the upstream side to the downstream side, and any one of the above-described methods 1) to 3) may be applied with gradation, or two or more methods may be combined. .

  Further, it is more preferable that the screw brush 71 has a brush diameter on the most upstream side in the toner conveyance direction set to be larger than that of other portions. As shown in FIG. 4, inside the housing 70, the toner brushes are formed at both ends of the screw brush 71 in the toner conveyance direction because toner is difficult to convey. Among these, since the toner collection bottle is installed at the downstream end, there is no problem even if the toner reservoir is formed, since it is appropriately discharged to the toner collection bottle (small toner reservoir). However, the upstream end (uppermost stream side) forms a large toner reservoir (toner reservoir large), and the accumulated toner may blow out from the gap or the lump may fall out of the housing 70.

  By setting the brush diameter of the portion 71a corresponding to the most upstream side of the screw brush 71 to be larger than the brush diameter of the other portion, the portion 71a formed with the brush diameter larger than the other portion is the photosensitive drum 22. The opening of the cleaner unit 23 opposite to the end is securely sealed. It is possible to effectively prevent toner scattering and toner dropping at the upstream end of the cleaner unit 23 in the toner transport direction in the housing 70.

  Moreover, in order to improve the sealing performance of the portion 71a corresponding to the most upstream side, in addition to increasing the brush diameter, only the portion 71a may be increased in the flocking density.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

10 Image forming device 22 Photosensitive drum 23 Cleaner unit (cleaning device)
24 Charger 71 Screw brush 72 Cleaning blade 81 Brush part 82 Non-brush part 83 Brush hair

Claims (8)

A cleaning blade that contacts the surface of the photosensitive drum and removes residual toner from the surface;
The brush part in which the brush bristles are implanted and the non-brush part in which the bristles are not implanted are spirally provided, and the toner removed from the surface of the photosensitive drum by the cleaning blade is conveyed to the toner collecting part. A screw brush to
A housing for housing these,
The above-mentioned screw brush is disposed so that the brush hair contacts the inner wall of the housing.   The cleaning device according to claim 1, wherein the screw brush is disposed such that the brush hair is not in contact with the photosensitive drum.   The cleaning device according to claim 1, wherein the screw brush is provided so that the toner conveying capability on the downstream side is higher than the upstream side in the toner conveying direction.   The cleaning device according to claim 3, wherein the screw brush has a bristle pile diameter that is set to be larger on the downstream side than on the upstream side in the toner conveying direction.   5. The cleaning device according to claim 3, wherein the screw brush is a brush hair of a screw brush in which a flocking density of the brush hair is set higher on the downstream side than on the upstream side in the toner conveying direction.   6. The cleaning device according to claim 3, wherein the screw brush has a spiral brush portion whose pitch is set larger on the downstream side than on the upstream side in the toner conveyance direction.   The cleaning device according to any one of claims 1 to 6, wherein the screw brush has a brush diameter at a most upstream portion in a toner conveying direction set to be larger than a brush diameter at other portions.   An image forming apparatus comprising the cleaning device according to claim 1.

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