JP5124546B2 - Image forming apparatus cleaning apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a cleaning device and an image forming apparatus used in an image forming apparatus such as a copying machine or a printer.

  As an image forming apparatus such as a copying machine, a photosensitive drum on which an electrostatic latent image is formed on a surface, a developing unit that develops a toner image on the electrostatic latent image formed on the photosensitive drum, and a photosensitive drum An intermediate transfer belt that temporarily holds the formed toner image and forms a multicolor image thereon, a primary transfer roller that transfers the toner image formed on the photosensitive drum to the intermediate transfer belt, and an intermediate It is known to include a secondary transfer roller that transfers a toner image transferred to a transfer belt onto a sheet. Such an image forming apparatus is provided with a cleaning device for removing residual toner remaining on the intermediate transfer belt after the toner image is transferred to a sheet (see, for example, Patent Document 1).

  The cleaning device includes a cleaning brush that contacts the intermediate transfer belt to remove toner from the intermediate transfer belt, a recovery roller that contacts the cleaning brush and collects toner from the cleaning brush, and a voltage application that applies a voltage to the recovery roller. A section. Since the cleaning brush is in contact with the collection roller, the surface of the cleaning brush is negatively charged. On the other hand, the toner is positively charged. For this reason, the toner is electrostatically adsorbed to the cleaning brush and the collection roller and removed from the intermediate transfer belt.

JP 2008-225252 A

  Generally, when the resistance value of the cleaning brush and the resistance value of the toner are compared, the resistance value of the toner is higher. For this reason, in the cleaning device described above, the current density between the cleaning brush and the collection roller between the portion of the cleaning brush where a large amount of toner adheres (the toner high-density adhering portion) and the portion where the toner does not adhere. The difference is made. Originally, it is preferable to efficiently move the toner to the collecting roller between the cleaning brush and the collecting roller by increasing the current density of the toner high density adhering portion of the cleaning brush. However, in reality, since the resistance value of the toner high density adhering portion of the cleaning brush is increased, the current density of the toner high density adhering portion is lowered, and the toner removal efficiency from the cleaning brush is deteriorated. There was a problem.

  Further, the toner remaining on the image bearing member such as the photosensitive drum and the intermediate transfer belt is a mixture of positively charged toner and negatively charged toner. For this reason, in the cleaning device described in Patent Document 1, the positively chargeable toner can be removed from the photosensitive drum, but the negatively chargeable toner cannot be removed from the photosensitive drum, and the efficiency is low. There was a problem.

  An object of the present invention is to provide a cleaning device for an image forming apparatus capable of improving the efficiency of removing toner from the surface of an image carrier and an image forming apparatus provided with the cleaning device.

  The present invention is a cleaning device that removes toner remaining on the surface of an image carrier of an image forming apparatus from the surface and cleans the surface, wherein the image carrier is brought into contact with the surface of the image carrier. A cleaning member for removing toner from the surface of the body, a recovery roller for recovering from the cleaning member by adsorbing toner removed from the surface of the image carrier by the cleaning member, and a contact with the recovery roller; A toner scraping member that scrapes off the toner adsorbed to the collecting roller, the cleaning member is charged to a polarity opposite to that of the toner by friction with the toner, and the collecting roller includes the toner and the cleaning member. The present invention relates to a cleaning device for an image forming apparatus that is charged to a polarity opposite to that of toner due to friction of the toner.

  The toner is positively charged due to friction between the toner and the cleaning member, and the cleaning member is negatively charged, and the toner is positively charged due to friction between the toner and the cleaning member and the collecting roller. It is preferable that the recovery roller is further charged to the negative side as compared with the cleaning member.

  In this case, an electric field forming unit that forms an electric field between the image carrier and the collection roller is further provided, and the electric field is positive on the image carrier side and negative on the collection roller side. Is preferred.

  The toner is negatively charged due to friction between the toner and the cleaning member, and the cleaning member is positively charged, and the toner is negatively charged due to friction between the toner and the cleaning member and the collecting roller. It is preferable that the recovery roller is further charged to the plus side as compared with the cleaning member.

  In this case, an electric field forming unit that forms an electric field between the image carrier and the collection roller is further provided, and the electric field is negative on the image carrier side and positive on the collection roller side. Is preferred.

  The collecting roller includes a conductive portion and an insulating portion provided on a surface of the conductive portion, and the insulating portion is charged to a polarity opposite to that of the toner due to friction with the toner and the cleaning member. preferable.

  The toner scraping member is preferably disposed at an angle of 15 ° to 20 ° outward with respect to a tangential direction between the toner scraping member and the collecting roller.

  According to another aspect of the present invention, there is provided an image forming apparatus including the above-described cleaning device for an image forming apparatus, the second image carrier having an electrostatic latent image formed on a surface thereof, and the second image carrier. A developing unit that develops a toner image on an electrostatic latent image; the image carrier; a first transfer unit that transfers a toner image formed on the second image carrier to the image carrier; and the image carrier. The present invention relates to an image forming apparatus including a second transfer unit that transfers a toner image transferred to a sheet-like transfer material, and the cleaning device.

  According to the present invention, the efficiency of removing toner from the surface of the image carrier can be improved.

FIG. 3 is a diagram for explaining each component of the copier 1 of the present embodiment. 3 is a diagram for explaining a cleaning device 100, photosensitive drums 2a, 2b, 2c, and 2d and an intermediate transfer belt 7. FIG. 2 is a diagram for explaining a cleaning device 100. FIG.

Embodiments of the present invention will be described below with reference to the drawings.
First, the overall structure of the copier 1 as an image forming apparatus will be described with reference to FIG. FIG. 1 is a diagram for explaining the arrangement of each component of the copier 1.

  As shown in FIG. 1, a copying machine 1 as an image forming apparatus includes an image reading device 300 arranged on the upper side of the copying machine 1 and image information from the image reading device 300 arranged on the lower side of the copying machine 1. And an apparatus main body M that forms a toner image on a sheet T as a sheet-like transfer material.

The image reading apparatus 300 will be described.
As shown in FIG. 1, the image reading apparatus 300 includes a lid member 70 and a reading unit 301 that reads an image of a document G.
The lid member 70 is connected to the reading unit 301 so as to be opened and closed by a connecting unit (not shown). The lid member 70 has a function of protecting a reading surface 302A described later.

  The reading unit 301 moves in a direction parallel to the reading surface 302A, an illumination unit 340 including a light source disposed in the internal space 304 of the reading unit 301, a plurality of mirrors 321, 322, and 323, and the reading surface 302A. The first frame 311 and the second frame 312, the imaging lens 357, the CCD 358 as a reading device, and the image data read by the CCD 358 are subjected to predetermined processing and the image data is transferred to the apparatus main body M side. A CCD substrate 361 for output.

The reading surface 302A is formed along the upper surface in the vertical direction of the contact glass 302 on which the document G is placed.
The illumination unit 340 and the mirror 321 described above are accommodated in the first frame 311. The mirrors 322 and 323 are accommodated in the second frame 312.

  In the internal space 304 of the reading unit 301, the plurality of mirrors 321, 322, and 323 form an optical path H for allowing light from the original G to enter the imaging lens 357. In addition, the first frame 311 moves at a constant speed A in the sub-scanning direction X, and the second frame 312 moves at a constant speed A / 2 in the sub-scanning direction X. The length of H is kept constant. Thereby, the image of the original G placed on the reading surface 302A is read.

The apparatus main body M will be described.
The apparatus main body M is configured to form a predetermined toner image on the paper T based on predetermined image information, and to feed the paper T to the image forming unit and to discharge the paper T on which the toner image is formed. And a paper supply / discharge unit.
The outer shape of the apparatus main body M is configured by a case body M2 as a casing.

  As shown in FIG. 1, the image forming unit includes photosensitive drums 2a, 2b, 2c, and 2d as second image carriers, charging units 10a, 10b, 10c, and 10d, and a laser scanner unit 4a as an exposure unit. 4b, 4c, 4d, developing devices 16a, 16b, 16c, 16d, toner cartridges 5a, 5b, 5c, 5d, toner supply units 6a, 6b, 6c, 6d, and drum cleaning units 11a, 11b, 11c. 11d, static eliminators 12a, 12b, 12c, and 12d, an intermediate transfer belt 7 as an image carrier, primary transfer rollers 37a, 37b, 37c, and 37d as a first transfer unit, and a second transfer unit Secondary transfer roller 8, counter roller 18, and fixing unit 9.

  As shown in FIG. 1, the paper feed / discharge unit includes a paper feed cassette 52, a manual paper feed unit 64, a conveyance path L for paper T, a registration roller pair 80, a first paper discharge unit 50 a, and a second paper feed unit. A paper discharge unit 50b. As will be described later, the transport path L includes a first transport path L1, a second transport path L2, a third transport path L3, a manual transport path La, a return transport path Lb, and a post-processing transport path Lc. Is a collection of

Hereinafter, each configuration of the image forming unit and the paper supply / discharge unit will be described in detail.
First, the image forming unit will be described.
In the image forming unit, charging by the charging units 10a, 10b, 10c, and 10d in order from the upstream side to the downstream side with respect to the respective surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, and the laser scanner units 4a, 4b, 4c, 4d exposure, development devices 16a, 16b, 16c, 16d development, intermediate transfer belt 7 and primary transfer rollers 37a, 37b, 37c, 37d primary transfer, static eliminators 12a, 12b, 12c, 12d And cleaning by the drum cleaning units 11a, 11b, 11c, and 11d.

  In the image forming unit, secondary transfer by the intermediate transfer belt 7, the secondary transfer roller 8 and the counter roller 18, and fixing by the fixing unit 9 are performed.

  Each of the photosensitive drums 2a, 2b, 2c, and 2d is formed of a cylindrical member and functions as a photosensitive member. Each of the photosensitive drums 2 a, 2 b, 2 c, and 2 d is disposed so as to be rotatable in the direction of an arrow about an axis that extends in a direction orthogonal to the traveling direction of the intermediate transfer belt 7. An electrostatic latent image can be formed on the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d.

  Each of the charging units 10a, 10b, 10c, and 10d is disposed to face the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the charging units 10a, 10b, 10c, and 10d uniformly charges the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d negatively (minus polarity) or positively (plus polarity).

  The laser scanner units 4a, 4b, 4c, and 4d function as exposure units, and are spaced apart from the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the laser scanner units 4a, 4b, 4c, and 4d includes a laser light source (not shown), a polygon mirror, a polygon mirror driving motor, and the like.

  Each of the laser scanner units 4a, 4b, 4c, and 4d scans and exposes the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d based on image information related to the image read by the reading unit 301. The scanning exposure is performed by each of the laser scanner units 4a, 4b, 4c, and 4d, thereby removing the charges on the exposed portions of the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Thereby, electrostatic latent images are formed on the respective surfaces of the photosensitive drums 2a, 2b, 2c, and 2d.

  The developing devices 16a, 16b, 16c, and 16d are provided corresponding to the photosensitive drums 2a, 2b, 2c, and 2d, respectively, and are disposed to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the developing devices 16a, 16b, 16c, and 16d attaches the toner of each color to the electrostatic latent image formed on the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d, and converts the color toner image into the photosensitive drum. 2a, 2b, 2c and 2d are formed on the respective surfaces. Each of the developing devices 16a, 16b, 16c, and 16d corresponds to four colors of yellow, cyan, magenta, and black. Each of the developing devices 16a, 16b, 16c, and 16d includes a developing roller that can be disposed opposite to the surface of the photosensitive drums 2a, 2b, 2c, and 2d, a stirring roller for stirring the toner, and the like.

  Each of the toner cartridges 5a, 5b, 5c, and 5d is provided corresponding to each of the developing devices 16a, 16b, 16c, and 16d, and each color toner supplied to each of the developing devices 16a, 16b, 16c, and 16d. To accommodate. Each of the toner cartridges 5a, 5b, 5c, and 5d accommodates yellow toner, cyan toner, magenta toner, and black toner.

  The toner supply units 6a, 6b, 6c, and 6d are provided corresponding to the toner cartridges 5a, 5b, 5c, and 5d and the developing devices 16a, 16b, 16c, and 16d, respectively. The toners of the respective colors accommodated in 5d are supplied to the developing devices 16a, 16b, 16c, and 16d, respectively. Each of the toner supply units 6a, 6b, 6c, and 6d and each of the developing devices 16a, 16b, 16c, and 16d are connected by a toner supply path (not shown).

  To the intermediate transfer belt 7, the toner images of the respective colors formed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially primary-transferred. The intermediate transfer belt 7 is stretched around a driven roller 35, a counter roller 18 including a driving roller, a tension roller 36, and the like. Since the tension roller 36 biases the intermediate transfer belt 7 from the inside to the outside, a predetermined tension is applied to the intermediate transfer belt 7.

  A cleaning device 100 for cleaning the intermediate transfer belt 7 is disposed on the opposite side of the intermediate transfer belt 7 from the driven roller 35. The cleaning device 100 includes a cleaning brush (cleaning member) 110 disposed so as to be in contact with the surface of the intermediate transfer belt 7, a collection roller 120 disposed so as to be in contact with the cleaning brush 110, and a leading end of the collection roller 120. A blade (toner scraping member) 130 disposed so as to be in contact with the surface. Details of the cleaning device 100 will be described later.

  Primary transfer rollers 37a, 37b, 37c, and 37d are arranged to face each other on the side opposite to the photosensitive drums 2a, 2b, 2c, and 2d with the intermediate transfer belt 7 interposed therebetween.

  A predetermined portion of the intermediate transfer belt 7 is sandwiched between the primary transfer rollers 37a, 37b, 37c, and 37d and the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The predetermined portion thus sandwiched is pressed against the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. Primary transfer nips N1a, N1b, N1c, and N1d are formed between the photosensitive drums 2a, 2b, 2c, and 2d and the primary transfer rollers 37a, 37b, 37c, and 37d, respectively. In the primary transfer nips N1a, N1b, N1c, and N1d, the respective color toner images developed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially transferred to the intermediate transfer belt 7. As a result, a full-color toner image is formed on the intermediate transfer belt 7.

  The primary transfer rollers 37a, 37b, 37c, and 37d respectively transfer the color toner images formed on the photosensitive drums 2a, 2b, 2c, and 2d to the intermediate transfer belt 7 by a primary transfer bias applying unit (not shown). A primary transfer bias for transferring is applied.

  The static eliminators 12a, 12b, 12c, and 12d are arranged to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The static eliminators 12a, 12b, 12c, and 12d respectively irradiate the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d to irradiate light, and the photosensitive drums 2a, 2b, and 2c after the primary transfer is performed. 2d, each surface is neutralized (charge is removed).

  The drum cleaning units 11a, 11b, 11c, and 11d are disposed to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, respectively. Each of the drum cleaning units 11a, 11b, 11c, and 11d removes toner and adhering matter remaining on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, and conveys the removed toner to a predetermined recovery mechanism. And collect it.

  The secondary transfer roller 8 secondarily transfers the toner image primarily transferred to the intermediate transfer belt 7 onto the paper T. A secondary transfer bias as a voltage for transferring the full-color toner image formed on the intermediate transfer belt 7 to the paper T is applied to the secondary transfer roller 8 by a secondary transfer bias applying unit (not shown). .

  A counter roller 18 is arranged on the opposite side of the intermediate transfer belt 7 from the secondary transfer roller 8, and a secondary transfer nip N <b> 2 is formed between the secondary transfer roller 8 and the intermediate transfer belt 7. The toner image primarily transferred to the intermediate transfer belt 7 is secondarily transferred to the paper T in the secondary transfer nip N2.

  The fixing unit 9 melts and presses each color toner constituting the toner image secondarily transferred onto the paper T to fix it on the paper T. The fixing unit 9 includes a fixing roller 9a heated by a heater and a pressure roller 9b pressed against the fixing roller 9a. The fixing roller 9a and the pressure roller 9b sandwich and press the paper T on which the toner image is secondarily transferred, and convey the paper T. When the paper T is conveyed while being sandwiched between the fixing roller 9a and the pressure roller 9b, the toner transferred to the paper T is fixed to the paper T by being melted and pressed.

Next, the paper supply / discharge unit will be described.
As shown in FIG. 1, in the lower part of the apparatus main body M, two paper feed cassettes 52 that store paper T are arranged in an up-down direction. The paper feed cassette 52 is configured to be pulled out from the housing of the apparatus main body M in the horizontal direction. In the paper feed cassette 52, a placement plate 60 on which the paper T is placed is disposed. In the paper feed cassette 52, the paper T is stored in a state of being stacked on the placement plate 60. The paper T placed on the placement plate 60 is sent out to the transport path L by the cassette paper feed unit 51 arranged at the end of the paper feed cassette 52 on the paper feed side (the left end in FIG. 1). The cassette paper feed unit 51 includes a double feed prevention mechanism including a forward feed roller 61 for taking out the paper T on the placement plate 60 and a paper feed roller pair 63 for feeding the paper T to the transport path L one by one. Prepare.

  A manual paper feed unit 64 is provided on the right side surface (right side in FIG. 1) of the apparatus main body M. The manual paper feed unit 64 is provided mainly for supplying the apparatus main body M with a paper T of a size and type different from the paper T set in the paper feed cassette 52. The manual paper feed unit 64 includes a manual feed tray 65 that forms a part of the apparatus main body M in the closed state, and a paper feed roller 66. The lower end of the manual feed tray 65 is attached to the vicinity of the paper feed roller 66 so as to be rotatable (openable and closable). The paper T is placed on the open manual feed tray 65. The manual paper feed unit 64 feeds the paper T placed on the open manual feed tray 65 to the manual feed path La.

  A first paper discharge unit 50 a and a second paper discharge unit 50 b are provided on the upper side of the apparatus main body M. The first paper discharge unit 50a and the second paper discharge unit 50b discharge the paper T to the outside of the apparatus main body M. Details of the first paper discharge unit 50a and the second paper discharge unit 50b will be described later.

  The conveyance path L for conveying the paper T includes a first conveyance path L1 from the cassette paper feeding unit 51 to the secondary transfer nip N2, a second conveyance path L2 from the secondary transfer nip N2 to the fixing unit 9, and a fixing unit. 9 to the first paper discharge section 50a, the manual conveyance path La for joining the paper supplied from the manual paper feed section 64 to the first conveyance path L1, and the third conveyance path L3 on the upstream side. The paper transported from the upstream side to the downstream side is reversed and returned to the first transport path L1, and the paper transporting the third transport path L3 from the upstream side to the downstream side is connected to the second paper discharge unit 50b. And a post-processing transport path Lc for transporting to a post-processing apparatus (not shown).

Moreover, the 1st junction part P1 and the 2nd junction part P2 are provided in the middle of the 1st conveyance path L1. A first branch portion Q1 is provided in the middle of the third transport path L3.
The first joining part P1 is a joining part where the manual feed path La joins the first transport path L1. The second junction P2 is a junction where the return conveyance path Lb merges with the first conveyance path L1.
The first branch portion Q1 is a branch portion where the post-processing transport path Lc branches from the third transport path L3. A rectifying member 58 is provided in the first branch portion Q1. The rectifying member 58 rectifies the transport direction of the paper T carried out from the fixing unit 9 to the third transport path L3 toward the first paper discharge section 50a or the post-processing transport path Lc toward the second paper discharge section 50b ( Switch).

  In the middle of the first transport path L1 (specifically, between the second joining portion P2 and the secondary transfer roller 8), a sensor for detecting the paper T and correction of the skew (oblique paper feeding) of the paper T In addition, a registration roller pair 80 for adjusting the timing with the toner image is disposed. The sensor is disposed immediately before the registration roller pair 80 in the transport direction of the paper T (upstream in the transport direction). The registration roller pair 80 conveys the paper T by performing the above-described correction and timing adjustment based on detection signal information from the sensor.

  The return conveyance path Lb is a conveyance path that is provided so that the opposite surface (non-printing surface) to the surface that has already been printed faces the photosensitive drum 2 when performing duplex printing on the paper T. According to the return transport path Lb, the paper T transported from the first branching section Q1 to the paper discharge section 50 is turned upside down and returned to the first transport path L1 and arranged upstream of the secondary transfer roller 8. It can be conveyed to the upstream side of the pair of registration rollers 80. A predetermined toner image is transferred onto the non-printing surface by the photosensitive drum 2 on the paper T that has been turned upside down by the return conveyance path Lb.

  A first paper discharge unit 50a is formed at the end of the third transport path L3. The first paper discharge unit 50 a is disposed on the upper side of the apparatus main body M. The first paper discharge unit 50a opens toward the right side of the apparatus main body M (the right side in FIG. 1, the manual paper feed unit 64 side). The first paper discharge unit 50a discharges the paper T transported through the third transport path L3 to the outside of the apparatus main body M.

  On the opening side of the first paper discharge section 50a, a paper discharge stacking section M1 is formed. The paper discharge stacking unit M1 is formed on the upper surface (outer surface) of the apparatus main body M. The paper discharge stacking unit M1 is a part formed by the upper surface of the apparatus main body M being depressed downward. The bottom surface of the paper discharge stacking unit M1 constitutes a part of the top surface of the apparatus main body M. In the paper discharge stacking unit M1, sheets T formed with a predetermined toner image and discharged from the first paper discharge unit 50a are stacked and stacked.

  A second paper discharge unit 50b is formed at the end of the post-processing conveyance path Lc. The second paper discharge unit 50b is disposed on the upper side of the apparatus main body M. The second paper discharge section 50b opens toward the left side of the apparatus main body M (left side in FIG. 1, the side to which the post-processing apparatus is connected). The second paper discharge unit 50b discharges the paper T conveyed through the post-processing conveyance path Lc to the outside of the apparatus main body M.

A post-processing device (not shown) is connected to the opening side of the second paper discharge unit 50b. The post-processing device performs post-processing (stapling, punching, etc.) of paper ejected from the image forming apparatus (copy machine 1).
A paper detection sensor is disposed at a predetermined position on each conveyance path.

Next, a paper jam (JAM) in the main transport path L1 to L3 (the first transport path L1, the second transport path L2, and the third transport path L3 are collectively referred to as “main transport path” hereinafter) and the return transport path Lb. A structure for eliminating the problem will be briefly described.
As shown in FIG. 1, on the left side surface (left side in FIG. 1) of the apparatus main body M, main conveyance paths L1 to L3 and a return conveyance path Lb are arranged in parallel so as to mainly extend in the vertical direction. A cover body 40 is provided on the left side of the apparatus body M (left side in FIG. 1) so as to form a part of the side surface of the apparatus body M. The cover body 40 is connected to the apparatus main body M via a fulcrum shaft 43 at the lower end thereof. The fulcrum shaft 43 is disposed along the direction in which the axial direction crosses the main transport paths L1 to L3 and the return transport path Lb. The cover body 40 is configured to be rotatable between a closed position (position shown in FIG. 1) and an open position (not shown) with the fulcrum shaft 43 as a center.

  The cover body 40 includes a first cover portion 41 that is rotatably connected to the apparatus main body M by a fulcrum shaft 43, and a second cover portion 42 that is rotatably connected to the apparatus main body M by the same fulcrum shaft 43. It consists of and. The first cover portion 41 is located on the outer side (side surface side) of the apparatus main body M than the second cover portion 42. In FIG. 1, the hatched portion with the left-down dashed line is the first cover portion 41, and the hatched portion with the right-down dashed line is the second cover portion 42.

In the state where the cover body 40 is located at the closed position, the outer surface side of the first cover portion 41 forms a part of the outer surface (side surface) of the apparatus main body M.
Further, in the state where the cover body 40 is located at the closed position, the inner surface side (the apparatus main body M side) of the second cover portion 42 forms a part of the main transport paths L1 to L3.
Further, in a state where the cover body 40 is located at the closed position, the inner surface side of the first cover portion 41 and the outer surface side of the second cover portion 42 form at least a part of the return conveyance path Lb. That is, the return conveyance path Lb is formed between the first cover part 41 and the second cover part 42.

  The copying machine 1 of the present embodiment includes the cover body 40 having such a configuration, so that when a paper jam (JAM) occurs in the main transport paths L1 to L3, the cover body 40 is closed as shown in FIG. By rotating from the position to an open position (not shown) to open the main transport paths L1 to L3, it is possible to process paper jammed in the main transport paths L1 to L3. On the other hand, when a paper jam occurs in the return conveyance path Lb, the cover body 40 is rotated to the open position, and then the second cover portion 42 is moved to the apparatus main body M side (right side in FIG. ) To open the return conveyance path Lb, the paper jammed in the return conveyance path Lb can be processed.

  Next, with reference to FIGS. 2 and 3, the cleaning device 100 of the copier 1 in this embodiment will be described in detail. FIG. 2 is a diagram for explaining the cleaning device 100, the photosensitive drums 2a, 2b, 2c, and 2d and the intermediate transfer belt 7. FIG. 3 is a diagram for explaining the cleaning device 100.

  As shown in FIGS. 2 and 3, the cleaning device 100 of this embodiment includes a cleaning brush 110, a collection roller 120, and a blade 130. The cleaning brush 110 is in contact with the surface of the intermediate transfer belt 7 and removes the toner TN from the surface of the intermediate transfer belt 7. The cleaning brush 110 is disposed on the opposite side of the intermediate transfer belt 7 from the driven roller 35 so as to be rotatable in the direction (arrow B direction) opposite to the moving direction of the intermediate transfer belt 7 (arrow A direction). The driven roller is grounded.

  When the toner TN is negatively charged, the cleaning brush 110 is formed of a conductive fiber such as a rayon conductive yarn. The cleaning brush 110 is charged with a polarity opposite to that of the toner TN due to friction with the toner TN. Specifically, the cleaning brush 110 is triboelectrically charged by rubbing against the toner TN adhering to the surface of the intermediate transfer belt 7 and the toner TN adhering to the cleaning brush 110. At this time, the cleaning brush 110 becomes positively charged due to the frictional charging series. On the other hand, in the toner TN, the toner that is positively charged on the intermediate transfer belt 7 (image carrier) is also negatively charged due to the frictional charging series. Here, the frictional charging series is a series of which is positively charged and which is negatively charged when friction occurs between two objects. Generally, the amount of electrification due to friction is larger between objects that are far from each other than objects that are close to each other in the friction charging series.

  The collection roller 120 is a roller that collects the toner TN removed from the surface of the intermediate transfer belt 7 by the cleaning brush 110 to collect it from the cleaning brush 110. The collection roller 120 is disposed on the opposite side of the driven roller 35 across the cleaning brush 110 so as to be rotatable in a direction (arrow C direction) opposite to the rotation direction of the cleaning brush 110 (arrow B direction). Further, the collection roller 120 is configured by a member located further away from the toner TN with the cleaning brush 110 interposed therebetween in the triboelectric charging series.

  The collection roller 120 is charged so as to be opposite in polarity to the toner TN and to have a larger charge amount per unit area than the cleaning brush 110 due to friction with the toner TN and the cleaning brush 110. Specifically, the collection roller 120 is frictionally charged by rubbing against the cleaning brush 110 and the adhered toner TN. At this time, the collection roller 120 becomes positively charged due to the frictional charging series. On the other hand, the toner TN becomes negatively charged due to the frictional charging series. Furthermore, the potential of the collection roller 120 is higher than that of the cleaning brush 110 due to the frictional charging series. That is, the potential of the collection roller 120 is further increased to the plus side as compared with the cleaning brush 110.

  The collection roller 120 includes a conductive part 121 and an insulating part 122 provided on the surface of the conductive part 121. The conductive part 121 is made of a conductive material such as metal. The insulating part 122 is made of a coating layer made of an insulating material such as a tube or a coat. The insulating part 122 is charged with a polarity opposite to that of the toner TN due to friction with the toner TN. When the toner TN is negatively charged, the collection roller 120 is formed, for example, from a roller in which an aluminum pipe is covered with a nylon tube and heat-sealed. A power source 140 (electric field forming unit) is connected to the collection roller 120 and the intermediate transfer belt 7. In the present embodiment, a positive voltage is applied to the collection roller 120. As a result, an electric field is generated between the intermediate transfer belt 7 and the collection roller 120.

  The blade 130 contacts the collection roller 120 and scrapes off the toner TN adsorbed on the collection roller 120. The blade 130 is made of, for example, a urethane material. The blade 130 is disposed so as to have an angle of 15 ° to 20 ° (cleaning angle θ) outward with respect to a tangent line D between the blade 130 and the collection roller 120.

  The blade 130 is preferably made of a material having a rebound resilience of 35% or less. Accordingly, it is possible to prevent the external additive or the like of the toner TN adsorbed on the collection roller 120 from slipping through the blade 130 and causing the wear on the surface of the collection roller 120 to progress from the slipped-off location. That is, the stick-slip cycle is lengthened and the amplitude of the blade 130 is reduced by stick-slip, so that the external additive of the toner TN can be prevented from slipping through.

Next, the operation of the cleaning device 100 will be described.
The intermediate transfer belt 7 rotates in the arrow A direction. The toner images formed on the photosensitive drums 2a, 2b, 2c, and 2d are transferred by primary transfer rollers 37a, 37b, 37c, and 37d. In this way, the color toner images are superimposed on the primary transfer rollers 37a, 37b, 37c, and 37d. Thereafter, the intermediate transfer belt 7 is pressed against the paper T by the secondary transfer roller 8. As a result, the toner image on the intermediate transfer belt 7 is secondarily transferred onto the surface of the paper T. The negatively or positively charged toner TN remains on the intermediate transfer belt 7 after the secondary transfer, and the toner TN is conveyed to the cleaning brush 110 by the rotation of the intermediate transfer belt 7.

  Since the cleaning brush 110 rotates in the direction of arrow B, when the toner TN remaining on the intermediate transfer belt moves, the toner TN and the cleaning brush 110 rub against each other, and the cleaning brush 110 and the cleaning brush 110 are separated by a triboelectric charging series. The toner TN is charged with a reverse polarity. Specifically, the toner TN is negatively charged and the cleaning brush 110 is positively charged. Here, even when the positively chargeable toner TN adheres to the intermediate transfer belt 7, the toner TN changes to negative chargeability due to friction between the toner TN and the cleaning brush 110. As a result, the toner TN is electrostatically attracted to the cleaning brush 110 and removed from the intermediate transfer belt 7.

Since the collection roller 120 rotates in the direction of arrow C, the toner TN, the cleaning brush 110, and the collection roller 120 rub against each other, and the collection roller 120 and the toner TN are charged to opposite polarities by the frictional charging series. Specifically, the toner TN is negatively charged and the collection roller 120 is positively charged. Here, according to the triboelectric charging series of the cleaning brush 110 and the collection roller 120, since the positive chargeability of the collection roller 120 is larger than that of the cleaning brush 110, the potential on the positive side of the collection roller 120 is set to the cleaning brush 110. Is much more charged. Further, since a positive voltage is applied to the collection roller 120, an electric field is generated between the collection roller 120 and the intermediate transfer belt 7. As a result, the toner TN is electrostatically attracted to the collection roller 120 and removed from the cleaning brush 110.
The toner TN adsorbed on the collection roller 120 is scraped off by the blade 130 and collected.

According to the cleaning device 100 of the copier 1 of the present embodiment as described above, the following effects are exhibited.
According to the present embodiment, the cleaning brush 110 is charged with a reverse polarity to the toner TN due to friction with the toner TN, and the recovery roller 120 has a reverse polarity with respect to the toner TN due to friction with the toner TN and the cleaning brush 110. Charged. Specifically, due to the friction between the toner TN and the cleaning brush 110, the toner TN is negatively charged and the cleaning brush 110 is positively charged. Further, the toner TN and the friction between the cleaning brush 110 and the collecting roller 120 cause the toner TN to be negatively charged, and the collecting roller 120 is further charged to the positive side as compared with the cleaning brush 110. Therefore, the toner TN can be electrostatically removed from the surface of the intermediate transfer belt 7, and the removal efficiency of the toner TN can be improved.

  Further, according to the present embodiment, the power supply 140 that forms an electric field between the intermediate transfer belt 7 and the collection roller 120 is provided, and a positive voltage is applied to the collection roller 120. Therefore, an electric field is formed in which the collection roller 120 side becomes positive and the intermediate transfer belt 7 side becomes negative, and the toner TN adhering to the intermediate transfer belt 7 is electrostatically adsorbed to the collection roller 120 via the cleaning brush 110. Can do.

  Further, according to the present embodiment, the collection roller 120 includes the conductive portion 121 and the insulating portion 122 provided on the surface of the conductive portion 121. The insulating portion 122 is separated from the toner TN by friction with the toner TN. Is charged to the opposite polarity. Therefore, the toner TN and the insulating portion 122 are rubbed with each other, and the toner TN and the insulating portion 122 can be charged with opposite polarities by the frictional charging series.

  In addition, according to the present embodiment, the blade 130 is disposed with an angle of 15 ° to 20 ° on the outside with respect to the tangent line D between the blade 130 and the collection roller 120. Therefore, even when the toner TN is not collected by the blade 130 and used for a long time, it is possible to prevent the blade 130 from stably contacting the collecting roller 120 and causing the blade 130 to be turned up.

As mentioned above, this invention is not limited to embodiment mentioned above, It can implement with a various form.
In the above-described embodiment, the case where the toner TN is negatively charged has been described. However, the toner TN may be positively charged. In this case, the cleaning brush 110 is formed using, for example, acrylic or polyester. The collection roller 120 is formed of a roller in which the surface of the conductive portion 121 is covered with a fluororesin-based material (PFA, PTFE) or the like.

  As a result, even when the positively charged or negatively charged toner TN remains on the intermediate transfer belt 7, the toner TN is positively charged by the friction between the toner TN and the cleaning brush 110, and the cleaning brush 110 is negatively charged. To do. That is, even when the negatively charged toner TN adheres to the intermediate transfer belt 7, the toner TN changes to positive charge due to friction between the toner TN and the cleaning brush 110. Further, the toner TN attracted to the cleaning brush 110 and the friction between the cleaning brush 110 and the collection roller 120 cause the toner TN to be positively charged, and the recovery roller 120 is negatively charged.

  Here, according to the triboelectric charging series of the cleaning brush 110 and the collection roller 120, the collection roller 120 is more negatively charged than the cleaning brush 110, and therefore the collection roller 120 has a more negative potential than the cleaning brush 110. Is charged. Further, the power source 140 connected to the collection roller 120 and the intermediate transfer belt 7 is configured to apply a negative voltage to the collection roller 120, and an electric field is generated between the collection roller 120 and the intermediate transfer belt 7. . As a result, the toner TN adhering to the intermediate transfer belt 7 is electrostatically adsorbed to the cleaning brush 110 from the intermediate transfer belt 7, and then electrostatically adsorbed to the collection roller 120 and scraped off by the blade 130.

In this embodiment, the toner image is transferred to the transfer material (paper T) via the intermediate transfer belt 7 (indirect transfer method), but the present invention is not limited to this, and the intermediate transfer belt is not used. The toner image can also be transferred directly to the sheet-shaped transfer material (paper T) (direct transfer method). In the case of this direct transfer method, the cleaning device 100 cleans the transfer belt directly.
Further, the cleaning device 100 can clean, for example, the photosensitive drum regardless of the object to be cleaned.

In addition, the sheet-shaped transfer material is the paper T in the present embodiment, but is not limited thereto, and may be, for example, a film sheet.
The cleaning member is the cleaning brush 110 in the present embodiment, but is not limited thereto, and a member such as a sponge may be used.
In this embodiment, the copying machine 1 is described as an image forming apparatus. However, a printer, a facsimile, a complex machine of these, or the like may be used.

  DESCRIPTION OF SYMBOLS 1 ... Copy machine (image forming apparatus), 2a, 2b, 2c, 2d ... Photosensitive drum (image carrier (second image carrier)), 7 ... Intermediate transfer belt (image carrier), 8 ... ... secondary transfer roller, 35 ... driven roller, 100 ... cleaning device, 110 ... cleaning brush (cleaning member), 120 ... collection roller, 121 ... conductive part, 122 ... insulating part, 130 ... blade (Toner scraping member), 140... Power source (electric field forming part), G... Original, H .. optical path, TN.

Claims (8)

A cleaning device for cleaning the surface by removing toner remaining on the surface of the image carrier of the image forming apparatus from the surface,
A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier;
A recovery roller that recovers from the cleaning member by adsorbing toner removed from the surface of the image carrier by the cleaning member;
A toner scraping member that contacts the collecting roller and scrapes off the toner adsorbed on the collecting roller;
With
The cleaning member is charged with the opposite polarity to the toner by friction with the toner,
The collection roller is a cleaning device for an image forming apparatus in which the toner is charged to a polarity opposite to that of the toner by friction between the toner and the cleaning member. Due to the friction between the toner and the cleaning member, the toner is positively charged, and the cleaning member is negatively charged,
The image according to claim 1, wherein the toner is positively charged due to friction between the toner and the cleaning member and the recovery roller, and the recovery roller is further negatively charged as compared with the cleaning member. A forming device cleaning device. An electric field forming part for forming an electric field between the image carrier and the collection roller;
The image forming apparatus cleaning device according to claim 2, wherein the electric field is positive on the image carrier side and negative on the collection roller side. Due to the friction between the toner and the cleaning member, the toner is negatively charged, and the cleaning member is positively charged.
2. The image according to claim 1, wherein the toner is negatively charged due to friction between the toner and the cleaning member and the recovery roller, and the recovery roller is further positively charged as compared to the cleaning member. A forming device cleaning device. An electric field forming part for forming an electric field between the image carrier and the collection roller;
The image forming apparatus cleaning device according to claim 4, wherein the electric field is negative on the image carrier side and positive on the collection roller side. The collection roller includes a conductive portion and an insulating portion provided on a surface of the conductive portion,
The image forming apparatus cleaning device according to claim 1, wherein the insulating portion is charged with a polarity opposite to that of the toner by friction with the toner. 7. The toner scraping member is disposed at an angle of 15 ° to 20 ° outward with respect to a tangential direction between the toner scraping member and the collecting roller. A cleaning device for an image forming apparatus. An image forming apparatus comprising the image forming apparatus cleaning device according to claim 1,
A second image carrier on which an electrostatic latent image is formed on the surface;
A developer for developing a toner image on the electrostatic latent image formed on the second image carrier;
The image carrier;
A first transfer unit that transfers the toner image formed on the second image carrier to the image carrier;
A second transfer portion for transferring the toner image transferred to the image carrier to a sheet-like transfer material;
An image forming apparatus comprising the cleaning device.

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