JP2017040736A - Cleaning device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a toner removed by a brush roller from entering a space between a rotary shaft of the brush roller and a bearing hole of a bearing member.SOLUTION: A rotary shaft 35a of a brush roller 35 removing a residual toner from a surface of an intermediate transfer belt 7 has a shield member 43 fixed thereto, which covers a bearing hole 41a of a bearing member 41 from an insertion side of the rotary shaft 35a to be in slide contact with the bearing member 41.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image forming apparatus such as a printer, a copying machine, and a facsimile, and a cleaning device used for the image forming apparatus.

  Patent Document 1 discloses a cleaning device in which a drive gear fitted to one end of a rotating shaft of a brush roller and a photosensitive drum (image carrier) are partitioned by a dust-proof film, and an image forming apparatus including the cleaning device Is disclosed.

  According to this, it is possible to prevent the residual toner on the photosensitive drum removed by the brush roller from entering between the photosensitive drum and the driving gear and clogging between the teeth of the driving gear. The rotation is guaranteed and the toner removal by the brush roller can be performed smoothly.

JP 11-31933 A

  However, since both ends of the rotating shaft of the brush roller are inserted into the bearing holes of the bearing member and are rotatably supported by the bearing member, the drive gear and the photosensitive drum are partitioned by a dust-proof film as in Patent Document 1. However, the toner removed by the brush roller enters between the rotating shaft of the brush roller and the bearing hole of the bearing member.

  In that case, since the toner may contain components such as titanium in the external additive and components such as iron in the developer, the outer peripheral surface of the rotating shaft of the brush roller and the inner peripheral surface of the bearing hole of the bearing member are scraped. There may be irregularities.

  As a result, when the brush roller rotates, minute vibrations and rotational fluctuations occur, making it difficult to hold the toner, and the toner returns to the photosensitive drum and stains the image surface.

  The same applies to a cleaning device that removes residual toner on the intermediate transfer belt (intermediate transfer member) in addition to the cleaning device for the photosensitive drum (image carrier).

  The present invention has been made in view of such a point, and an object of the present invention is to prevent the toner removed by the brush roller from entering between the rotating shaft of the brush roller and the bearing hole of the bearing member. It is.

  The cleaning device according to the present invention includes a brush roller that removes residual toner from an image carrier or an intermediate transfer member, a collection roller that collects the removed toner from the brush roller, and a toner that is collected by the collection roller. The brush roller has a rotating shaft having both ends inserted into the bearing holes of the bearing member and rotatably supported by the bearing member. Is fixed with a shielding member that covers the bearing hole from the insertion side of the rotary shaft and is in sliding contact with the bearing member.

  According to this, since the bearing hole of the bearing member is covered by the shielding member from the insertion side of the rotating shaft of the brush roller, the toner removed by the brush roller does not enter between the rotating shaft and the bearing hole and rotates. The situation where the outer peripheral surface of the shaft and the inner peripheral surface of the bearing hole are shaved by the entering toner and become uneven is avoided. Therefore, there is no minute vibration or rotational fluctuation at the time of rotation of the brush roller due to the unevenness, and the toner removed by the brush roller does not return to the image carrier or the intermediate transfer member to contaminate the image surface.

  In this case, the surface of the shielding member on the bearing member side is formed to be a flat surface so as to be in surface contact with the bearing member, and the surface of the shielding member on the side opposite to the bearing member is rotated by the shielding member. It is desirable that a concavo-convex portion that generates an airflow toward the outer periphery of the roller is formed.

  According to this, the toner removed by the brush roller and scattered on the bearing member side is pushed back toward the outer periphery of the brush roller by the air flow generated by the rotation of the shielding member, and enters between the rotating shaft and the bearing hole. Is effectively suppressed. In addition, since the surface of the shielding member on the bearing member side comes into surface contact with the bearing member with an equal force, it is possible to suppress shaving due to uneven contact stress with the shielding member of the bearing member and to stabilize rotation.

  The distance from the rotation center of the shielding member to the outer periphery is preferably shorter than the distance from the rotation center of the brush roller to the outer periphery.

  According to this, it is possible to prevent as much as possible a situation in which the toner removed by the brush roller and scattered to the bearing member side greatly fluctuates in the cleaning device and adheres to the image carrier or intermediate transfer member.

  Moreover, it is desirable that the concavo-convex portion is composed of a plurality of blade-like convex portions and concave portions between adjacent blade-like convex portions.

  According to this, airflow is efficiently generated by the rotation of the shielding member.

  Moreover, it is desirable that the blade-like convex portion is inclined forward and downward in the rotation direction of the shielding member.

  According to this, airflow is more efficiently generated by the rotation of the shielding member.

  Further, it is desirable that the blade-like convex portion is formed so as to gradually become wider from the rotation center of the shielding member toward the outer periphery.

  According to this, the toner removed by the brush roller and scattered on the bearing member side is smoothly pushed back toward the outer periphery of the brush roller.

  An image forming apparatus according to the present invention includes the cleaning device described above.

  According to this, since the toner removed by the brush roller does not enter between the rotating shaft and the bearing hole, it is possible to form a high-quality image.

  According to the present invention, by covering the bearing hole of the bearing member with the shielding member from the insertion side of the rotating shaft of the brush roller, the toner removed by the brush roller enters between the rotating shaft and the bearing hole, and the outer periphery of the rotating shaft The surface of the bearing and the inner peripheral surface of the bearing hole are uneven, so that minute vibrations and rotational fluctuations during rotation of the brush roller are eliminated, and the toner removed by the brush roller returns to the image carrier or intermediate transfer member to form the image surface. Can be avoided.

FIG. 1 is a schematic diagram illustrating the overall configuration of the image forming apparatus. FIG. 2 is a schematic cross-sectional view showing the configuration of the cleaning device. FIG. 3 is a schematic perspective view showing the configuration of the cleaning device. FIG. 4 is a front view showing a state in which the brush roller is supported by the bearing member. FIG. 5 is a perspective view of the shielding member. FIG. 6 is a side view of the shielding member. FIG. 7 is a front view of the shielding member of the first modification. FIG. 8 is a front view of the shielding member of the second modification. FIG. 9 is a front view of the shielding member of the third modification. FIG. 10 is a side view of the shielding member of the fourth modification. FIG. 11 is a front view of the shielding member of the fifth modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment.

  FIG. 1 is a schematic diagram illustrating the overall configuration of the image forming apparatus 1. The image forming apparatus 1 is, for example, a tandem color printer, and includes a developing unit A, an intermediate transfer unit B disposed above the developing unit A, and a plurality (four) of the intermediate transfer unit B disposed above the intermediate transfer unit B. ) Toner container C. The image forming apparatus 1 also includes a primary transfer unit 6, a secondary transfer unit 9, a fixing unit 11, and an optical scanning device 15. The developing unit A has a plurality (four) of image forming units 16 disposed above the optical scanning device 15. The intermediate transfer unit B includes an endless intermediate transfer belt (intermediate transfer member) 7, and the intermediate transfer belts 7 are arranged above the four image forming units 16 along the arrangement direction of the image forming units 16. ing.

  A paper feed cassette 3 is disposed below the inside of the apparatus main body 2 of the image forming apparatus 1. The paper feed cassette 3 stores and accommodates paper before printing (not shown) therein. A first paper transport unit 21 is provided on the side of the paper feed cassette 3. The first paper transport unit 21 receives the paper fed from the paper feed cassette 3 and transports the paper to the upper secondary transfer unit 9.

  A manual paper feed unit 5 is provided on the side of the paper feed cassette 3 opposite to the first paper transport unit 21. A second paper transport unit 22 is provided between the manual paper feed unit 5 and the first paper transport unit 21. The second paper transport unit 22 receives the paper sent from the manual paper feed unit 5 and transports it to the first paper transport unit 21.

  The optical scanning device 15 is disposed above the second paper transport unit 22 and irradiates the image forming unit 16 with laser light based on the image data received by the image forming device 1. The intermediate transfer belt 7 is wound around a driving roller 12 and a driven roller 13 and is rotationally driven by a driving device (not shown). 14 is a tension roller.

  The intermediate transfer belt 7 is configured such that a toner image is transferred from the outer peripheral surfaces of the plurality of photosensitive drums 25 by contacting the outer peripheral surfaces of the plurality of photosensitive drums (image bearing members) 25.

  The four image forming units 16 are arranged in a line along the intermediate transfer belt 7 and respectively form yellow, magenta, cyan, or black toner images. Each image forming unit 16 includes a photosensitive drum 25, a charger 31, a developing unit 33, and a cleaning device 32 disposed around the photosensitive drum 25.

  The charger 31 charges the surface of the photosensitive drum 25. An electrostatic latent image is formed on the photosensitive drum 25 charged by the charger 31 by the laser light emitted from the optical scanning device 15. The developing unit 33 forms a toner image on the surface of the photosensitive drum 25 by developing the electrostatic latent image.

  The primary transfer unit 6 is disposed above each image forming unit 16. The primary transfer unit 6 includes a primary transfer roller 8 that primarily transfers the toner image formed on the photosensitive drum 25 by the image forming unit 16 onto the surface of the intermediate transfer belt 7.

  Then, the intermediate transfer belt 7 is driven to rotate, and the toner image on each photoconductive drum 25 is transferred to the intermediate transfer belt at a predetermined timing with a voltage opposite to the charging polarity of the toner applied to the primary transfer roller 8. 7, a color toner image in which toner images of four colors of yellow, magenta, cyan, and black are superimposed on each other is formed on the surface of the intermediate transfer belt 7. Further, the surface of the photosensitive drum 25 on which the toner image is transferred to the intermediate transfer belt 7 is cleaned by the cleaning device 32.

  The secondary transfer unit 9 has a secondary transfer roller 17 disposed on the side of the intermediate transfer belt 7. The secondary transfer unit 9 sends the toner image on the intermediate transfer belt 7 from the first paper transport unit 21 at a voltage opposite in polarity to the charging polarity of the toner applied to the secondary transfer roller 17. It is designed to be transferred to a sheet of paper.

  A cleaning device 34 for cleaning the surface of the intermediate transfer belt 7 is disposed on the side of the driven roller 13 opposite to the secondary transfer portion 9 of the intermediate transfer belt 7.

  The fixing unit 11 is provided above the secondary transfer unit 9. Between the secondary transfer unit 9 and the fixing unit 11, a third paper transport unit 23 that transports the paper on which the toner image is secondarily transferred to the fixing unit 11 is formed. The fixing unit 11 includes a pressure roller 18, a fixing roller 19, and a heating roller 20. The fixing unit 11 heats and pressurizes the sheet conveyed from the third sheet conveying unit 23 to fix the toner image on the sheet.

  A branch portion 27 is provided above the fixing portion 11. The sheet discharged from the fixing unit 11 is discharged from the branching unit 27 to the sheet discharging unit 28 formed on the upper portion of the image forming apparatus 1 when double-sided printing is not performed. When performing duplex printing, the paper is conveyed again from the branching unit 27 to the secondary transfer unit 9 via the fourth paper conveying unit 24.

  An inner unit D is arranged on the front side of the intermediate transfer unit B so as to cover the front side of the intermediate transfer unit B (see the alternate long and short dash line), and the toner is transferred from the toner container C to the developing unit 33 of the developing unit A via the inner unit D. To supply.

As shown in FIGS. 2 and 3, the cleaning device 34 includes a brush roller 35 made of a fur brush arranged to face the driven roller 13 with the intermediate transfer belt 7 interposed therebetween. The brush roller 35 has a rotating shaft 35a made of stainless steel (SUS), and has a medium resistance (about 10 ⁶ to 10 ⁹ Ω) fiber made of an insulating resin such as acrylic or polyester and made conductive with carbon or the like. The rotary shaft 35a is wound around. The brush roller 35 contacts the intermediate transfer belt 7 while rotating in the opposite direction, and removes residual toner from the intermediate transfer belt 7.

  A collection roller 36 having a rotation shaft 36 a is disposed in contact with the brush roller 35. The collection roller 36 is constituted by stainless steel (SUS) or stainless steel (SUS) provided with a resistance layer such as alumite or nylon rubber. The collection roller 36 collects the toner removed from the intermediate transfer belt 7 from the brush roller 35 by the collection roller 36.

  A rubber blade 37 is disposed in contact with the collection roller 36, and the toner collected by the collection roller 36 is scraped off by the blade 37.

  A discharge screw 38 for conveying the collected toner to a waste toner bottle (not shown) is disposed below the blade 37.

  A leakage prevention sheet 39 is provided between the discharge screw 38 and the brush roller 35 to block the collected toner from leaking to the brush roller 35 side.

  Reference numeral 40 denotes a voltage application unit that applies a voltage to the brush roller 35 via the collection roller 36 so that the surface of the brush roller 35 is negatively charged. The driven roller 13 is grounded.

  The brush roller 35 and the collection roller 36 are rotatably supported by the bearing member 41 by inserting both ends of the rotary shafts 35a and 36a into two bearing holes 41a of a bearing member 41 made of polyacetal (POM).

  The bearing member 41 is biased by a spring 42, and the fiber portion of the brush roller 35 is in contact with the intermediate transfer belt 7 with a predetermined pressure.

  As shown in FIG. 4, a disc-shaped shielding member 43 is fixed to the rotation shaft 35 a of the brush roller 35. In the center of the shielding member 43, an insertion hole 43a is formed for inserting the rotating shaft 35a when the shielding member 43 is fixed to the rotating shaft 35a (see FIG. 5).

  As shown in FIGS. 5 and 6, the surface of the shielding member 43 on the bearing member 41 side (the surface on the right side in FIG. 4 and the surface on the left side in FIG. The flat surface 44 slidably contacts the bearing member 41 by covering the bearing hole 41a from the insertion side of the rotating shaft 35a.

  The shielding member 43 is formed of a resin such as polycarbonate (PC) having a certain rigidity. It is not preferable to use a metal having high hardness for the shielding member 43 because it generates shavings by sliding with the bearing member 41 and this may adhere to the intermediate transfer belt 7.

  On the surface of the shielding member 43 on the side opposite to the bearing member 41 (the surface on the left side in FIG. 4, the surface on the right side in FIG. 6), an uneven portion 45 that generates an air flow toward the outer periphery of the brush roller 35 is formed. Has been.

  The distance from the rotation center of the shielding member 43 to the outer periphery is set shorter than the distance from the rotation center of the brush roller 35 to the outer periphery. That is, the diameter of the shielding member 43 is smaller than the diameter of the brush roller 35 as shown in FIGS.

  As shown in FIG. 5, the concavo-convex portion 45 includes four blade-like convex portions 45a extending radially from the periphery of the insertion hole 43a so as to divide the circumference into four equal parts, and four concave portions between adjacent blade-like convex portions 45a. 45b. The blade-like convex portion 45a is a substantially rectangular shape whose width is slightly narrower as it is away from the insertion hole 43a, and is linearly inclined forward and downward in the rotation direction of the shielding member 43 (see FIGS. 5 and 6). ). The recess 45b has a fan shape.

  In the cleaning device 34 configured as described above, since the toner supplied to the intermediate transfer belt 7 is positively charged, a voltage is applied to the collection roller 36 so that the surface of the brush roller 35 is negatively charged. ing. The brush roller 35 having a negatively charged surface rotates while the brush bristles are in contact with the intermediate transfer belt 7, thereby removing residual toner on the intermediate transfer belt 7 by physical contact and electrostatic force. Then, the toner removed by the brush roller 35 is collected by the collection roller 36 at a nip that contacts the rotating collection roller 36, the collected toner is scraped off by the blade 37, and the scraped toner is discharged. The screw 38 is conveyed to a waste toner bottle (not shown).

  By the way, since both ends of the rotating shaft 35a are inserted into the bearing holes 41a of the bearing member 41 and are rotatably supported by the bearing member 41, the brush roller 35 is removed by the brush roller 35 without the shielding member 43. The toner enters between the rotating shaft 35 a of the brush roller 35 and the bearing hole 41 a of the bearing member 41.

  Then, since the toner may contain components such as titanium in the external additive and components such as iron in the developer, the outer surface of the rotating shaft 35a of the brush roller 35 and the inner periphery of the bearing hole 41a of the bearing member 41 are included. The surface may be shaved and uneven.

  As a result, when the brush roller 35 rotates, minute vibrations and rotational fluctuations occur, making it difficult to hold the toner, and the toner returns to the intermediate transfer belt 7 and stains the image surface.

  However, in this embodiment, since the bearing hole 41a of the bearing member 41 is covered with the shielding member 43 from the insertion side of the rotating shaft 35a of the brush roller 35, the toner removed by the brush roller 35 is removed from the rotating shaft 35a and the bearing hole. Therefore, the outer peripheral surface of the rotary shaft 35a and the inner peripheral surface of the bearing hole 41a are not scraped and become uneven by the toner that has entered. Therefore, there is no minute vibration or rotation fluctuation at the time of rotation of the brush roller 35 due to the unevenness, and it is possible to prevent the toner removed by the brush roller 35 from returning to the intermediate transfer belt 7 and staining the image surface. it can.

  Moreover, since the uneven part 45 which generates an air flow toward the outer periphery of the brush roller 35 by the rotation of the shielding member 43 is formed on the surface of the shielding member 43 on the side opposite to the bearing member 41, it is removed by the brush roller 35. The toner scattered on the bearing member 41 side is pushed back toward the outer periphery of the brush roller 35 by the air flow generated by the rotation of the shielding member 43, and the entry between the rotating shaft 35a and the bearing hole 41a is effectively suppressed. Can do.

  Further, since the surface on the bearing member 41 side of the shielding member 43 is formed on the flat surface 44 so as to be in surface contact with the bearing member 41, the surface on the bearing member 41 side of the shielding member 43 is a uniform force. It is possible to suppress the shaving due to uneven contact stress with the shielding member 43 of the bearing member 41 and to stabilize the rotation.

  Further, since the shielding member 43 has a diameter smaller than that of the brush roller 35, the toner removed by the brush roller 35 and scattered to the bearing member 41 side greatly rises in the cleaning device 34 and adheres to the intermediate transfer belt 7. Can be prevented as much as possible.

  Further, since the uneven portion 45 of the shielding member 43 is composed of four blade-like convex portions 45a and a concave portion 45b between adjacent blade-like convex portions 45a, an air flow is efficiently generated by the rotation of the shielding member 43. Can be made.

  In addition, since the blade-like convex portion 45 a is linearly inclined forward and downward in the rotation direction of the shielding member 43, the airflow can be generated more efficiently by the rotation of the shielding member 43.

  Therefore, in the image forming apparatus 1 including the cleaning device 34 as described above, the toner removed by the brush roller 35 does not enter between the rotating shaft 35a and the bearing hole 41a, so that a high-quality image can be formed.

  Although the modification of the shielding member 43 is shown below, it is not limited to these, For example, you may combine these suitably.

(Modification 1)
FIG. 7 is a front view of the shielding member 43 of the first modification. In the first modification, the four blade-like convex portions 45a are the same as in the embodiment in that they extend radially from the periphery of the insertion hole 43a so as to divide the circumference into four equal parts, but the blade-like convex portions 45a. However, it is different from the embodiment in that it is formed so as to gradually widen from the rotation center of the shielding member 43 toward the outer periphery.

  According to this, the toner removed by the brush roller 35 and scattered on the bearing member 41 side can be smoothly pushed back toward the outer periphery of the brush roller 35 by the wing-like convex portion 45a spreading toward the end.

(Modification 2)
FIG. 8 is a front view of the shielding member 43 of the second modification. This modification 2 is different from the embodiment in that the three blade-like convex portions 45a extend radially from the periphery of the insertion hole 43a so as to divide the circumference into three equal parts. In addition, although the shape of the blade-like convex portion 45a is a rectangle, the width may be slightly narrowed away from the insertion hole 43a as in the embodiment.

(Modification 3)
FIG. 9 is a front view of the shielding member 43 of the third modification. This modification 3 is different from the embodiment in that five blade-like convex portions 45a extend radially from the periphery of the insertion hole 43a so as to divide the circumference into five equal parts. Also in the third modification, the shape of the blade-like convex portion 45a is rectangular, but the width may be slightly narrowed as the distance from the insertion hole 43a is increased as in the embodiment.

(Modification 4)
FIG. 10 is a side view of the shielding member 43 of the fourth modification. The fourth modification is different from the embodiment in that the blade-like convex portion 45a is curved and inclined in a concave shape so as to be lowered forward in the rotation direction of the shielding member 43.

(Modification 5)
FIG. 11 is a front view of the shielding member 43 of the fifth modification. This modification 5 is different from the embodiment in that the blade-like convex portion 45a is three-dimensionally curved like a fan blade.

  According to this, air flow is efficiently generated by the rotation of the shielding member 43, and the toner scattered on the bearing member 41 side can be reliably and smoothly pushed back to the outer periphery of the brush roller 35.

  In the above embodiment, the cleaning device 34 for removing the residual toner on the intermediate transfer belt 7 has been described. However, the configuration of the present invention can also be applied to the cleaning device 32 for the photosensitive drum 25.

  In the above-described embodiment, the color printer has been described as an example of the image forming apparatus. However, the present invention is not limited to this. For example, other image forming apparatuses including the optical scanning device 15 such as a copying machine, a scanner device, or a multifunction device. It is good.

  As described above, the present invention is useful for the cleaning device and the image forming apparatus.

1 Image forming apparatus 7 Intermediate transfer belt (intermediate transfer member)
25 Photosensitive drum (image carrier)
32, 34 Cleaning device 35 Brush roller 35a Rotating shaft 36 Recovery roller 37 Blade 41 Bearing member 41a Bearing hole 43 Shielding member 44 Flat surface 45 Concavity and convexity 45a Blade-like convex portion 45b Concavity

Claims (7)

A brush roller for removing residual toner from the image carrier or intermediate transfer member;
A collection roller for collecting the removed toner from the brush roller;
A cleaning device comprising a blade for scraping off the toner collected by the collection roller,
The brush roller has a rotating shaft having both ends inserted into the bearing hole of the bearing member and rotatably supported by the bearing member,
A cleaning device, wherein a shielding member that covers the bearing hole from the insertion side of the rotation shaft and is in sliding contact with the bearing member is fixed to the rotation shaft. The cleaning device according to claim 1,
The surface on the bearing member side of the shielding member is formed as a flat surface so as to come into surface contact with the bearing member, and the surface of the shielding member on the side opposite to the bearing member is rotated by the rotation of the shielding member. The uneven | corrugated | grooved part which generate | occur | produces an airflow toward is formed. The cleaning device according to claim 1 or 2,
The cleaning device, wherein a distance from the rotation center of the shielding member to the outer periphery is shorter than a distance from the rotation center of the brush roller to the outer periphery. The cleaning device according to claim 2 or 3,
The said uneven | corrugated | grooved part is a cleaning apparatus comprised by the several blade-shaped convex part and the recessed part between adjacent blade-shaped convex parts. The cleaning apparatus according to claim 4.
The said blade-shaped convex part is a cleaning apparatus which inclines forward and downward toward the rotation direction of the said shielding member. The cleaning device according to claim 4 or 5,
The said blade-shaped convex part is a cleaning apparatus currently formed so that it may become wide gradually toward the outer periphery from the rotation center of the said shielding member.   An image forming apparatus comprising the cleaning device according to claim 1.

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