JP5403245B2 - Cleaning unit and image forming apparatus - Google Patents

Description

  The present invention relates to a cleaning unit used in an electrophotographic printer, a FAX, a copying machine, and the like, and an image forming apparatus including the same, and more particularly to a process until a toner layer developed on an electrostatic latent image is transferred to a recording medium. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt unit used, a cleaner unit for cleaning a toner layer electrostatically supported on a belt with a rubber blade, and an image forming apparatus including the same.

  For example, as shown in FIG. 13, the cleaning unit used in the image forming apparatus is wound around at least a pair of rollers 58 (upstream rollers are shown and downstream rollers are not shown). A cleaning blade 77 with which the lower end edge 80 of the leading end abuts on the transfer belt 60, a blade opposing roller 75 disposed inside the transfer belt 60 and receiving the cleaning blade 77 via the belt 60, and the cleaning blade 77. A cleaner case 71 that is scraped off and accommodates toner, and a conveying screw 73 that constitutes a conveying means for conveying the toner in the cleaner case 71. The cleaning blade 77 includes a blade member 77a and a holder 77b.

  That is, the illustrated upstream roller 58 serves as a driving roller, and the transfer belt 60 travels by driving the driving roller. At this time, the toner remaining on the transfer belt 60 by the lower end edge 80 at the leading end that abuts on the transfer belt 60 with the cleaning belt 77 and the blade facing roller 75 sandwiching the transfer belt 60 running in the direction of arrow A. Is scraped off and accommodated in the cleaner case 71. The toner stored in the cleaner case 71 is transported to a waste toner container (not shown) by a transport screw 73 that constitutes a transport means.

  However, as shown in FIG. 13, when the conveying screw 73 is disposed above the cleaning blade 77, the toner S and paper dust at the tip of the cleaning blade 77 or in the vicinity thereof are conveyed by the conveying screw 73. First, as shown in FIG.

  That is, the opening of the cleaner case 71 is closed by the cleaning blade 77 on the downstream side of the blade facing roller 75 and is closed by the seal member 74 on the upstream side of the blade facing roller 75. Therefore, the toner S or the like scraped by the cleaning blade 77 is blocked by the cleaning blade 77. Further, the seal member 74 cannot move upstream. For this reason, the toner S and paper dust accumulate on the tip of the cleaning blade 77 or in the vicinity thereof.

  Incidentally, the transfer belt 60 and the conveying screw 73 normally rotate in conjunction with each other, and are not conveyed to the waste toner container unless they are accumulated up to the height of the line B shown in FIG. That is, if the toner reaches the level of line B shown in FIG. 14, the toner S and the like are conveyed to the waste toner container. For this reason, the toner case S is not always full in the cleaner case 71. However, even in a state where it is not full, the paper dust and the like thus deposited may slip through between the blade edge (front end lower edge 80) and the transfer belt 60. Thus, if it slips through, it causes a cleaning failure.

  In view of this, conventionally, there have been some attempts to prevent such toner from slipping through (Patent Documents 1 to 3). According to Patent Document 1, by making the tip angle of the cleaning blade an obtuse angle shape, a high surface pressure can be applied with a lower linear pressure, and the load applied to the image carrier can be efficiently applied at the contact portion. This prevents the toner from slipping through. Japanese Patent Laid-Open No. 2004-228561 effectively prevents the toner from slipping through the contact portion and prevents the occurrence of defective cleaning by increasing the surface pressure as compared with the case where the end ridge line portion is a right angle. . In this case, since the second front end surface is inclined to the downstream side in the moving direction of the member to be cleaned with respect to the normal line of the surface of the member to be cleaned, the toner that contacts the second front end surface is forced to move away from the member to be cleaned. It becomes easy to receive, and the escape place of the toner which accumulates in the space | gap between a 1st front end surface and a to-be-cleaned member is made. As a result, even if the tip ridge line portion has an obtuse angle, it is possible to suppress the occurrence of cleaning failure due to the toner deposited on the upstream side of the contact portion. Also in Patent Document 3, by making the tip angle of the cleaning blade an obtuse angle, the surface pressure is increased without increasing the linear pressure, thereby preventing the toner from slipping through.

  In Patent Document 4, by making the tip angle an obtuse angle, the angle formed by the blade tip surface and the surface of the photosensitive drum is an acute angle, and the photosensitive drum is rotated in the normal rotation direction even when toner is likely to accumulate over time. And move the surface in the opposite direction. Accordingly, the accumulated toner can be removed with the cleaning brush, and the toner is prevented from being accumulated.

  Further, in Patent Document 5, the cleaning blade has a hardness, contact pressure, and contact angle set so that the residual toner can be efficiently removed from the surface of the image carrier.

  In Patent Document 6, the tip of the cleaning blade or the vicinity thereof has an acute angle in a V shape or a knife edge shape. In Patent Document 7, the angle formed by the two surfaces forming the tip edge is an acute angle in a state where the cleaning blade is not in contact with the surface to be cleaned (image carrier surface). This prevents a pressure drop per unit area of the cleaning blade on the surface of the image carrier.

  However, as shown in Patent Documents 1 to 3 and the like, even if the tip angle of the cleaning blade is an obtuse angle, the angle formed by the tip of the cleaning blade and the transfer belt is an acute angle. With such an acute angle, the toner, paper powder, and the like that enter the acute angle portion form a so-called wedge shape. If the wedge shape is formed, the toner or the like bites into the acute angle portion sequentially. If it bites in like this, the cleaning blade is lifted from the transfer belt, and a toner slipping phenomenon occurs. Even in Patent Document 7, the angle formed between the tip of the cleaning blade and the transfer belt is an acute angle, and toner omission cannot be effectively prevented.

  Further, in Patent Document 4, it is necessary to move the surface of the photosensitive drum in the direction opposite to the normal rotation direction, and efficient cleaning cannot be performed. In Patent Document 5, the residual developer is always accumulated due to the configuration in which the cleaning device is disposed above the image carrier. Accordingly, discharge products that are more likely to adhere to the image carrier and some additives and paper dust added to the transfer paper may be deposited on the image carrier.

  In Patent Document 6, a relatively soft rubber blade having a blade hardness of about 50 to 75 degrees is used. Therefore, when a dent is generated in the photosensitive member by pressing the blade, the blade edge is also distorted at the same time. Further, since the coefficient of friction of the photosensitive member is high, the tip of the blade or the vicinity thereof is caught in the photosensitive member and deformed. For this reason, a slight gap is formed between the blade and the photosensitive member, and the toner staying on the cleaning blade escapes through the gap between the blades, so-called toner omission occurs. The toner omission tends to be larger as the spherical toner is less caught.

  That is, the main cause of the cleaning failure of the cleaning unit in such an image forming apparatus or the like is due to paper dust caught between the leading edge of the cleaning blade (the leading edge and the bottom edge) and the edge contact portion of the transfer belt, Due to the cleaning blade being lifted or uneven wear of the leading edge of the cleaning blade, the toner or the like slips from between the leading edge and the edge contact portion to the downstream side. Further, it is conceivable that the cleaning blade in contact with the rotational force of the spherical toner deposited on or near the tip of the cleaning blade is lifted and the toner slips through.

  In view of such circumstances, the present invention effectively prevents toner omission without causing toner or paper dust scraped off by the cleaning blade to accumulate at or near the tip of the cleaning blade, thereby preventing poor cleaning. An object of the present invention is to provide a cleaning unit and an image forming apparatus that are difficult to generate.

The cleaning unit of the present invention has a cleaning blade that abuts from a counter direction that is a direction in which at least a tip lower end edge thereof resists the belt traveling direction on a belt wound around an upstream roller and a downstream roller, a cleaning unit comprising a blade facing roller disposed inside of the belt receiving the cleaning blade through a belt, an upper horizontal tangent of the upstream side of the upstream roller than blade facing roller, upper blade facing roller The angle between the belt between the upstream roller and the blade facing roller and the upper horizontal tangent of the upstream roller is 0 ° or more, and the lower end of the tip of the cleaning blade is disposed below the tangent in the horizontal direction. The belt contact part that is the edge passes through the axis of the blade facing roller. Together disposed on the upstream side of the line, the cleaning blade, is provided with a tapered or convex rounded shape of the notch on the corner portion between the tip surface and the top surface.

According to click leaning unit of the present invention, the upstream side of the cleaning blade, belt, will around lower toward the upstream side. For this reason, the tip of the cleaning blade or toner in the vicinity thereof moves to the upstream side. Further, by arranging the belt contact portion of the cleaning blade on the upstream side of the perpendicular passing through the axis of the blade facing roller, the toner or the like to be deposited on the tip of the cleaning blade or in the vicinity thereof has a wedge shape. Can prevent eggplant. In addition, by providing a tapered or convex round notch at the corner between the tip surface and the top surface of the cleaning blade, untransferred toner and paper dust deposited on the tip of the cleaning blade and in the vicinity thereof are transferred to the conveying screw. It becomes easy to carry naturally, and accumulation of untransferred toner and paper powder in the front end portion or in the vicinity thereof can be reduced.

A cleaner case for housing the toner scraped by the click leaning blade, and a conveying means for conveying the toner in the cleaner case, the conveying screw that constitutes the conveying means, the tip portion or its vicinity of the cleaning blade or it der those deposited toner is provided a blade member for guiding the conveyance screw side. Thus, by providing the blade member, the toner to be deposited on the tip of the cleaning blade or in the vicinity thereof can be guided to the conveying screw side, and the toner or the like can be prevented from accumulating in a wedge shape.

  It is preferable that the wing member is substantially perpendicular to the spiral rib of the conveying screw, and a gap is provided between the wing member and the spiral rib. Furthermore, it is preferable that the plurality of wing members are arranged at predetermined intervals along the axial direction of the conveying screw. The wing member is preferably provided with a through hole.

  The conveying screw includes two spiral ribs for forming two conveying paths, and the wing member can be disposed only in one conveying path. Further, the conveying screw constituting the conveying means includes two spiral ribs for forming two conveying paths, and one wing member is not provided with a wing member or provided with a through hole in one conveying path. And a wing member provided with a through hole may be disposed on the other transport path.

  An image forming apparatus of the present invention includes the above-described cleaning unit.

In click leaning unit of the present invention, toner and the like of the tip portion or its vicinity of the cleaning blade will be moved to the upstream side, it is possible to avoid the omission toner moves from the belt contact portion of the cleaning blade downstream . As a result, it becomes difficult to generate a cleaning defect, and high-precision cleaning can be performed. At this time, the belt contact sites, can be prevented Ri upstream der than a vertical line passing through the axis of the blade facing roller, toner and the like to be deposited on the distal end or its vicinity of the cleaning blade to form a wedge shape Further, toner omission can be avoided. In addition, by providing a tapered or convex round notch at the corner between the tip surface and the top surface of the cleaning blade, it is possible to prevent the toner and the like from forming a wedge shape, thereby avoiding toner omission. As a result, post-cleaning is less likely to occur and high-precision cleaning can be performed. Further, it is not necessary to cut the entire cleaning blade tip into an acute angle and an obtuse angle, and dimensional accuracy is not required, so that productivity can be improved.

When the wing member is provided, toner or the like can be prevented from accumulating in a wedge shape, and it becomes difficult to cause a cleaning failure, so that highly accurate cleaning can be performed. In addition, the toner or the like can be efficiently conveyed to the toner recovery unit. In addition, by providing the wing member, before a certain amount of untransferred toner or paper dust accumulates in the cleaner, it can be transported to the waste toner container by the transport screw, so that the cleaner capacity is afforded. be able to.

  By making the wing member substantially perpendicular to the spiral rib, the untransferred toner and paper dust collected by the wing member can be efficiently conveyed to the toner container by the conveying screw. Moreover, if a clearance is provided between the spiral ribs, it is possible to prevent a decrease in the conveying force of the conveying screw. That is, if there is no gap, when the toner scraped off by the wing member is conveyed by the conveying screw, the movement of the toner or the like is restricted by the wing member.

  If the plurality of blade members are arranged at predetermined intervals along the axial direction of the conveying screw, it is possible to prevent a decrease in the conveying force of the conveying screw and to reduce the recovery force of the toner or the like at the tip of the cleaning blade or in the vicinity thereof. Improvements can be made. Further, in the case where the through-hole is provided in the wing member, it is possible to prevent a reduction in the conveying force of the conveying screw as in the case where the gap is provided. Moreover, since it is not necessary to provide a gap with the spiral rib, the blade member can be fixed to the shaft main body portion and the spiral rib of the conveying screw, the strength of the blade member can be secured, and the blade tip or the deposit in the vicinity thereof can be secured. It is possible to prevent a reduction in recovery and diffusion functions.

  In the case of having two transport paths, the wing member is arranged only in one transport path, and the wing member is not disposed in the other transport path. Therefore, the toner or the like is stably transported by the other transport path. In addition, since one wing member is provided with one wing member, the wing member can prevent the toner or the like to be deposited on the tip of the cleaning blade or in the vicinity thereof from forming a wedge shape.

  In one having two transport paths, one wing member is not provided with a wing member or a wing member provided with a through hole is provided, and the other transport path is provided with a wing member provided with a through hole. With this arrangement, toner and the like can be stably conveyed in both conveyance paths, and the toner or the like that is to be deposited on the tip of the cleaning blade or in the vicinity thereof is arranged by the arranged blade member. The wedge shape can be prevented.

  In the image forming apparatus of the present invention, since the cleaning unit is provided, it is difficult to cause a cleaning failure, and a high-quality image can be stably formed over a long period of time.

1 is a simplified diagram showing a configuration of an image forming apparatus of the present invention. 2 is a simplified diagram of a cleaning unit of the image forming apparatus. FIG. It is a simplified diagram showing a modification of the cleaning unit. 4 shows another embodiment of the cleaning unit, where (a) is a simplified view when the tip surface of the cleaning blade is cut at 90 degrees, and (b) is a tip surface of the cleaning blade cut at an acute angle. (C) is a simplified view when the tip surface of the cleaning blade is cut at an obtuse angle. It is a principal part simplified view which shows another embodiment of a cleaning unit. FIG. 6A is a simplified view of a cleaning blade used in the cleaning unit shown in FIG. 5, and FIG. 6B is a simplified view of another cleaning blade used in the cleaning unit shown in FIG. 5. It is a principal part simplification figure which shows another embodiment of the cleaning unit. It is a principal part perspective view of the conveyance screw of the cleaning unit shown in the said FIG. It is a perspective view which shows the relationship between a conveyance screw and a wing member. It is a whole perspective view of a conveyance screw. It is a perspective view which shows the modification of a wing | blade member. The conveyance screw is shown, (a) is a perspective view of the conveyance screw whose spiral shape is one line, (b) is a perspective view of the conveyance screw whose spiral shape is two lines. It is a simplified diagram of a conventional cleaning unit. FIG. 6 is a simplified diagram illustrating a state where toner is accumulated in a conventional cleaning unit.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention according to embodiments shown in the drawings will be described.

  FIG. 1 is a schematic configuration diagram showing an electrophotographic color image forming apparatus according to the present invention. The image forming apparatus shown in FIG. 1 includes four process units 1Y, 1C, 1M, and 1Bk. Each of the process units 1Y, 1C, 1M, and 1Bk is configured to be detachable from the image forming apparatus main body 100.

  The process units 1Y, 1C, 1M, and 1Bk have the same configuration except that they contain toners of different colors of yellow, cyan, magenta, and black corresponding to the color separation components of the color image. Therefore, the configuration of one process unit 1Y will be described as an example.

  The process unit 1Y includes a photosensitive member 2 as an electrostatic latent image carrier, a charging roller 3 as a charging unit that charges the surface of the photosensitive member 2, and a developing unit that forms a toner image on the surface of the photosensitive member 2. A developing device 4 and a photosensitive member cleaning blade 5 as a cleaning means for cleaning the surface of the photosensitive member 2 are provided. Further, an exposure device 7 as an exposure unit that exposes the surface of the photoreceptor 2 is disposed above each process unit 1Y, 1C, 1M, 1Bk.

  The image forming apparatus shown in FIG. 1 is an intermediate transfer type image forming apparatus. Specifically, an intermediate transfer unit 6 having an endless intermediate transfer belt 10 is disposed below each process unit 1Y, 1C, 1M, 1Bk. The intermediate transfer belt 10 is stretched around a driving roller 8 and a driven roller 9 and is configured to be able to run around in the direction of the arrow in the figure. The driven roller 9 functions as a tension roller for applying a predetermined tension to the intermediate transfer belt 10.

  On the inner peripheral surface of the intermediate transfer belt 10, four primary transfer rollers (primary transfer members) 11 serving as primary transfer means are disposed to face the four photoconductors 2. The four photoconductors 2 are in pressure contact with the outer peripheral surface of the intermediate transfer belt 10, and a primary transfer nip is formed at each pressure contact portion.

  A secondary transfer roller (secondary transfer member) 12 as a secondary transfer unit is disposed at a position facing the driving roller 8 that stretches the intermediate transfer belt 10. The secondary transfer roller 12 is in pressure contact with the outer peripheral surface of the intermediate transfer belt 10, and forms a secondary transfer nip at the pressure contact portion. The drive roller 8 also functions as a secondary transfer counter roller that faces the secondary transfer roller 12 and receives the contact pressure of the secondary transfer roller 12.

  A cleaning unit U for cleaning the untransferred toner image remaining on the transfer belt 10 is disposed in the vicinity of the driving roller 8.

  Under the image forming apparatus main body 100, a recording material accommodating portion 13 that accommodates a recording material P such as paper or an OHP sheet is disposed. The recording material container 13 is provided with a supply roller 14 for carrying out the recording material P and the like.

  In the image forming apparatus main body 100, a conveyance path R for guiding the recording material P upward from the recording material accommodating portion 13 is disposed. A pair of registration rollers 15 a and 15 b are disposed on the upstream side (downward in the drawing) of the transport path R from the secondary transfer nip formed by the drive roller 8 and the secondary transfer roller 14. In addition, the fixing device 16 is disposed downstream of the secondary transfer nip in the conveyance direction of the conveyance path R (upward in the drawing). The fixing device 16 includes a heating roller 17 and a pressure roller 18. The heating roller 17 and the pressure roller 18 are in pressure contact with each other, and a fixing nip is formed at the pressure contact portion.

  A pair of discharge rollers 19 a and 19 b are disposed at the downstream end of the transport path R in the transport direction. In addition, a stock unit 20 on which the recording material P is stacked is formed by indenting the upper surface of the image forming apparatus main body 100 inward.

Hereinafter, a normal printing operation of the image forming apparatus will be described with reference to FIG.
In the process unit 1Y, the photosensitive member 2 is rotated in the direction of the arrow in the figure, and the surface of the photosensitive member 2 is charged to a uniform high potential by the charging roller 3. Next, a laser beam is irradiated from the exposure device 7 to the surface of the photoconductor 2 based on the image data, and the potential of the irradiated portion is lowered to form an electrostatic latent image. The toner charged by the developing device 4 is electrostatically transferred to the portion of the electrostatic latent image formed on the surface of the photoreceptor 2 to form a yellow toner image (visualization).

  The primary transfer roller 11 is applied with a constant voltage or a constant current controlled voltage having a polarity opposite to the charging polarity of the toner. As a result, a transfer electric field is formed in the primary transfer nip between the primary transfer roller 11 and the photoreceptor 2. Then, in the primary transfer nip, the toner image on the rotating photoconductor 2 is primarily transferred to the intermediate transfer belt 10 running in the direction of the arrow in the figure.

  In each of the other process units 1C, 1M, and 1Bk, a toner image is similarly formed on the photoreceptor 2, and the four color toner images are primarily transferred to the intermediate transfer belt 10 so as to overlap each other.

  Further, the surface of the photoreceptor 2 after the primary transfer process is cleaned by the photoreceptor cleaning blade 5 to remove residual toner. Further, the residual charge remaining on the surface of the photoreceptor 2 is neutralized by a neutralizing lamp (not shown).

  On the other hand, the recording material P stored in the recording material storage unit 13 is sent out to the transport path R by rotating the supply roller 14. The sent recording material P is temporarily stopped by the registration rollers 15a and 15b.

  Further, a voltage having a polarity opposite to the charging polarity of the toner is applied to the secondary transfer roller 12 to form a transfer electric field in the secondary transfer nip. Alternatively, a similar transfer electric field may be formed by applying a voltage having the same polarity as the charging polarity of the toner to the driving roller 8 facing the secondary transfer roller 12. Thereafter, the driving of the registration rollers 15a and 15b is resumed, and the recording material P is sent to the secondary transfer nip in synchronism with the toner image on the intermediate transfer belt 10. Then, the toner image on the intermediate transfer belt 10 is secondarily transferred collectively onto the recording material P by the transfer electric field formed in the secondary transfer nip.

  After the secondary transfer, the toner remaining on the surface of the intermediate transfer belt 10 is removed by the cleaning unit U, and the removed toner is collected in the waste toner container 30.

  The recording material P to which the toner image has been transferred is conveyed to the fixing device 16. The recording material P sent to the fixing device 16 is sandwiched between the heating roller 17 and the pressure roller 18 and heated and pressurized, and the toner image is fixed on the recording material P. Thereafter, the recording material P is discharged to the stock unit 20 by the discharge rollers 19a and 19b.

  Next, the cleaning unit U according to the present invention shown in FIG. 2 will be described. The cleaning unit U includes a cleaning blade 22 in which a tip lower end edge 40 contacts a belt (transfer belt 10) wound around an upstream roller (drive roller 8) and a downstream roller (driven roller 9), and the belt 10 A blade facing roller 25 that is disposed inside and receives the cleaning blade 22 via the belt 10, a cleaner case 21 that is scraped off by the cleaning blade 22 and stores toner, and a conveyance that conveys the toner in the cleaner case 21. Means M.

In this case, the horizontal tangent of (upper horizontal tangent) L1, horizontal tangent line (upper horizontal tangent line) below the L of the blade facing roller 25 on the upstream side of the upstream roller than the blade facing roller 25 (driving roller 8) To place. The angle θ formed by the belt 10 between the upstream roller 8 and the blade facing roller 25 and the horizontal tangent L1 of the upstream roller 8 is set to 0 ° or more. That is, when the distance between the horizontal tangent L1 and the horizontal tangent L is Δt, Δt ≧ 0. As a result, the angle θ becomes 0 ° or more.

  The cleaning blade 22 includes a blade member 22a and a holder 22b that holds the blade member 22a. The cleaner case 21 is inclined inward from the upper wall 21a, the side walls 21b and 21c depending from both ends of the upper wall 21a, and the lower side of the one (upstream side) side wall 21c. And an inclined wall 21d.

  A sealing member 24 is attached to the inclined wall 21d, and the cleaning blade 22 is disposed on the opposite side of the sealing member 24 so as to block the cleaner case 21. The blade member 22a of the cleaning blade 22 is inclined at a predetermined angle with respect to the horizontal tangent L. The inclination angle θ1 of the blade member 22a is, for example, about 30 degrees. For this reason, the front end surface 35 of the blade member 22a is inclined at (90 ° −θ1) with respect to the horizontal tangent L.

  Further, the seal member 24 includes a main body portion 24a extending along the inclination angle of the inclined wall 21d, and a horizontal portion 24b extending from the lower end of the main body portion 24a along the horizontal tangent L toward the blade member 22a. As a result, the opening on the inclined wall 21d side of the cleaner case 21 is closed. That is, the opening of the cleaner case 21 is closed by the cleaning blade 22 on the downstream side of the blade facing roller 25 and is closed by the seal member 24 on the upstream side of the blade facing roller 25.

  In the cleaning unit U configured as described above, the belt contact portion (tip lower end edge) 40 of the blade member 22a contacts the upper surface of the transfer belt 10 by traveling in the direction of the arrow A of the transfer belt 10 and the toner. S can be scraped off and cleaned.

  In the cleaner case 21, a conveying screw 23 that constitutes the conveying means M is disposed. For example, as shown in FIGS. 12A and 12B, the conveying screw 23 includes a shaft member 23a and a spiral rib 23b provided on the outer peripheral surface of the shaft member 23a. In this case, in FIG. 12A, one spiral rib 23b is provided, and in FIG. 12B, two spiral ribs 23b, 23c are provided. That is, one transport path T is formed in FIG. 12A, and two transport paths T1 and T2 are formed in FIG. 12B. For this reason, the conveying screw 23 in this embodiment may be the type shown in FIG. 12A or the type shown in FIG.

  In the cleaning unit U configured as shown in FIG. 2, the belt 10 is lowered toward the upstream side upstream of the cleaning blade 22. For this reason, the toner S, paper dust, and the like scraped off by the tip lower end edge 40 move to the upstream side as indicated by an arrow C. In other words, it is possible to avoid toner removal that moves downstream from the belt contact portion 40 of the cleaning blade 22. As a result, it becomes difficult to generate a cleaning defect, and high-precision cleaning can be performed.

  The tip of the blade member 22a of the cleaning blade 22 or toner in the vicinity thereof moves upstream as indicated by an arrow C, but is received by the seal member 24 and is not disposed outside the cleaner case 21. Thus, the toner S and the like accumulated in the cleaner case 21 enters the transport path T (see FIG. 12) of the transport screw 23 and is driven to the lower position of the intermediate transfer unit 6 by driving the transport screw 23. The waste toner container 30 is accommodated.

  By the way, as shown in FIG. 3, the blade member 22a of the cleaning blade 22 may be disposed such that the belt contact portion 40 is upstream of the perpendicular H passing through the axis O of the blade facing roller 25. . That is, when the difference between the perpendicular H1 passing through the belt contact portion 40 and the perpendicular H is Δa, Δa ≧ 0.

  As described above, when the belt contact portion 40 is upstream of the perpendicular passing through the axis of the blade facing roller 25, the toner or the like to be deposited on the tip of the cleaning blade 22 or in the vicinity thereof has a wedge shape. Can be prevented, and toner omission can be further avoided. As the blade member 22a of the cleaning blade 22, as shown in FIG. 6 (a) described later, a member provided with a tapered notch 37a at the corner portion between the tip surface 35 and the upper surface 36 is used. doing. In this case, even if it does not have the notch 37a as shown in FIG. 2, as shown in FIG. 6B, the rounded notch 37b is formed at the corner portion of the tip surface 35 and the upper surface 36. It may be provided.

  Next, in FIG. 4, the front end surface 35 of the cleaning blade 22 is maintained in a horizontal state as in the prior art without tilting the belt 10 (10 a) upstream of the cleaning blade 22 as in the above embodiment. And the angle α formed by the belt 10 (10a) on the upstream side of the blade facing roller 25 is about 90 °.

  In FIG. 4A, the front end surface 35 of the cleaning blade 22 is disposed so as to be parallel to the perpendicular H passing through the axis O of the blade facing roller 25. Therefore, the blade member 22a of the cleaning blade 22 is arranged in parallel with the belt 10 (10a) on the upstream side of the blade facing roller 25. Further, the belt 10 (10 b) on the downstream side of the blade facing roller 25 is sequentially lowered toward the downstream side so as to be separated from the cleaning blade 22 so that the cleaning blade 22 does not contact the belt 10. Under the present circumstances, the perpendicular H2 which passes along the front end surface 35 is arrange | positioned in the downstream rather than the said perpendicular H. FIG.

  In FIG. 4B, the tip surface 35 of the blade member 22a of the cleaning blade 22 is an inclined surface. In this case, the angle formed by the tip surface 35 and the lower surface of the blade member 22a is an acute angle. The belt 10 has an upstream side and a downstream side in the vicinity of the blade facing roller 25 arranged on the same horizontal plane. Then, by inclining the cleaning blade 22 with respect to the belt 10 at a predetermined angle, the angle α formed with the belt 10 on the tip surface 35 formed of this inclined surface is set to about 90 °.

  4C, the tip surface 35 of the blade member 22a of the cleaning blade 22 is an inclined surface, but the angle formed by the tip surface 35 and the lower surface of the blade member 22a is an obtuse angle. Then, by inclining the cleaning blade 22 with respect to the belt 10 at a predetermined angle, the angle α formed with the belt 10 on the tip surface 35 formed of this inclined surface is set to about 90 °. That is, the belt 10 on the downstream side of the blade facing roller 25 is sequentially lowered toward the downstream side so as to be separated from the cleaning blade 22, and the angle α formed between the cleaning blade 22 and the belt 10 on the tip surface 35 is about The cleaning blade 22 is swung in the + direction shown in FIG. 4A around the belt contact portion 40 so as to be 90 ° from the horizontal state.

  In the cleaning blade 22 shown in FIG. 4, the angle formed between the front end surface 35 of the cleaning blade 22 and the belt 10 (10a) is not an acute angle, and toner or the like to be deposited on the front end portion of the cleaning blade 22 or in the vicinity thereof. The wedge shape can be prevented. As a result, toner omission can be avoided, cleaning defects are less likely to occur, and highly accurate cleaning can be performed.

  In FIG. 4, the angle α formed by the tip surface 35 and the belt 10 is about 90 °, but the angle α may be larger than 90 °. In order to make the angle α larger than 90 °, the angle α may be inclined in the + direction of FIG. On the contrary, when the angle α is smaller than 90 °, the angle may be inclined in the negative direction in FIG.

  As described above, when the angle α is larger than 90 °, it is possible to effectively prevent the toner or the like to be deposited on the tip of the cleaning blade 22 or in the vicinity thereof from forming a wedge shape.

  Next, FIG. 5 shows a case where the cleaning blade 22 shown in FIG. 6 is used. In this case, the transfer belt 10 is inclined downward from the upstream side to the downstream side as in the conventional case shown in FIG. That is, as the transfer belt 10, the belt 10 (10a) between the upstream roller 8 and the blade facing roller 25 is not inclined at 0 ° or more with respect to the horizontal tangent L1 of the upstream roller 8.

  As shown in FIG. 5, by providing a tapered notch 37a at the corner between the tip surface 35 and the upper surface 36 of the cleaning blade 22, it is possible to prevent toner or the like from forming a wedge shape at the notch 37a. it can.

  For this reason, as shown in FIG. 6B, a convex round-shaped notch 37 b may be provided at a corner portion between the tip surface 35 and the upper surface 36 of the cleaning blade 22. Even in this case, it is possible to prevent the toner and the like from forming a wedge shape at the notch 37b.

  By the way, at the time of manufacturing the cleaning blade 22, when the leading edge is formed by cutting the material, it is easiest to cut the leading edge to be 90 °. Changing the tip edge angle leads to an increase in manufacturing cost, so it is desirable to cut the tip edge portion at 90 °. Therefore, after cutting the leading edge portion to 90 °, as a secondary processing, a corner that does not come into contact with the transfer belt 10, that is, a corner portion between the top surface and the leading surface may be chamfered. That is, a notch may be formed in the cleaning blade as in the fourth cleaning unit. By forming in this way, it is not necessary to cut the entire tip of the cleaning blade into an acute angle and an obtuse angle, and dimensional accuracy is not required, so that productivity can be improved.

  Next, in FIG. 7, a blade member 27 is provided on the conveying screw 23 constituting the conveying means M. The blade member 27 guides the toner S accumulated on the tip of the cleaning blade 22 or in the vicinity thereof to the conveying screw 23 side. At this time, the blade member 27 comes into sliding contact with the inner wall 22 of the cleaner case 21 by the rotation of the conveying screw 23.

  As shown in FIG. 8, the wing member 27 is made of, for example, a plate member, is substantially perpendicular to the spiral rib 23 b of the conveying screw 23, and has a gap δ (on the wing member 27 side) between the wing member 27 and the spiral rib 23 b. A gap is provided between the side 27a and the side surface of the spiral rib 23b. Since the wing member 27 is in sliding contact (contact) with the cleaner case 21 and the cleaning blade 22, for example, the wing member 27 can be formed of an elastic member such as a PET film having a thickness of about 0.1 mm. .

  Thus, by providing the wing member 27, the toner S to be deposited on the tip of the cleaning blade 22 or in the vicinity thereof can be guided to the conveying screw 23 side, and the toner or the like accumulates in a wedge shape. Can be prevented. Further, by providing the wing member 27, before a certain amount of untransferred toner or paper dust accumulates in the cleaner case 21, it can be conveyed to the waste toner container by the conveying screw 23, and the cleaner case capacity can be increased. You can make room. Note that it is possible to achieve a recovery efficiency of about 130% compared to the conventional configuration.

  By making the wing member 27 substantially perpendicular to the spiral rib 23 b, the untransferred toner and paper dust collected by the wing member 27 can be efficiently conveyed to the waste toner container 30 by the conveying screw 23. . In addition, if the gap δ is provided between the spiral rib 23b, the conveyance force of the conveyance screw 23 can be prevented from decreasing. That is, if there is no gap δ, the movement of the toner or the like is regulated by the blade member 27 when the toner or the like scraped off by the blade member 27 is conveyed by the conveyance screw 23.

  Further, as shown in FIG. 10, it is preferable that the plurality of wing members 27 are arranged at predetermined intervals along the axial direction of the conveying screw 23. If the plurality of wing members 27 are arranged at predetermined intervals along the axial direction of the conveying screw 23, it is possible to prevent a decrease in the conveying force of the conveying screw 23, and the toner at the tip of the cleaning blade 22 or the vicinity thereof. The recovery power can be improved.

  As shown in FIG. 11, the wing member 27 may be provided with a through hole 28. In the case where the through-hole 28 is provided in the wing member 27, similarly to the case where the gap δ is provided, the movement of the toner or the like is not restricted by the wing member 27, and a reduction in the conveying force of the conveying screw 23 can be prevented. . In addition, since it is not necessary to provide a gap with the spiral rib 23b, the wing member 27 can be fixed to the shaft main body 23a and the spiral rib 23b of the conveying screw 23. For this reason, the strength of the wing member 27 can be ensured, and the tip collection portion of the cleaning blade 22 or the deposit collection property in the vicinity thereof and the deterioration of the diffusion function can be prevented. In the wing member 27 shown in FIG. 11, a notch 29 is provided on the side 27a of the wing member 27, and the notch 29 is fitted to the spiral rib 23b.

  By the way, as described above, the conveying screw 23 has one conveying path T as shown in FIG. 12 (a) and two conveying paths T1 and T2 as shown in FIG. 12 (b). Some have. For this reason, if the wing member 27 is provided in the entire interval of the spiral rib 23b along the axial direction, the conveying path T is blocked by the wing member 27. For this reason, it is preferable to provide the wing members 27 at a predetermined interval as shown in FIG. 10 in the case of having one conveyance path T as shown in FIG.

  However, as shown in FIG. 12B, in the case of having two transport paths T1 and T2, even if the wing members 27 are arranged at all intervals on one of the transport paths T1 and T2, The other conveyance path can convey the toner without clogging the toner.

  In the case of having two transport paths T1, T2, the wing member 27 is not disposed in one transport path or the wing member 27 provided with the through hole 28 is disposed, and the other transport path T1 is disposed. , T2 may be provided with a wing member 27 provided with a through hole 28.

  In the case of having two transport paths T1 and T2, the wing member 27 is not disposed in one transport path or the wing member 27 provided with the through hole 28 is disposed, and the through hole 28 is disposed in the other transport path. In the case where the wing member 27 provided with is disposed, the toner or the like can be stably conveyed in both conveyance paths, and the wing member 27 is arranged so that the tip of the cleaning blade 22 or It is possible to prevent the toner or the like to be deposited in the vicinity from forming a wedge shape.

  As described above, when the above-described cleaning unit U is used in the image forming apparatus, it is difficult to generate a cleaning defect, and an image forming apparatus capable of stably forming a high-quality image over a long period of time can be configured.

  In addition, this invention is not limited to the above-mentioned Example, Of course, a various change can be added in the range which does not deviate from the summary of this invention. Examples of the image forming apparatus according to the present invention include an electrophotographic copying machine, a laser beam printer, and a facsimile machine. Further, the cleaning unit can be applied to residual toner cleaning of an image forming unit such as a photosensitive member or a transfer knit of an image forming apparatus, or a paper dust removing mechanism such as a transport belt or a paper transport roller. 2 and the like can be variously changed within a range in which the toner scraped off by the cleaning blade 22 moves in the direction of the arrow C and does not accumulate on the tip of the cleaning blade 22 or in the vicinity thereof. Further, the inclination angle of the tapered notch 37a in FIG. 6A, the radius of curvature of the rounded notch 37b in FIG. 6B, and the like are within a range that does not accumulate at the tip of the cleaning blade 22 or in the vicinity thereof. Various changes can be made. Furthermore, when the through hole 28 is provided in the wing member, the shape is rectangular in FIG. 11, but the shape is not limited to such a rectangular shape, and may be various shapes such as a circle, an ellipse, and a polygon. Further, the size of the through hole 28 can be variously changed within a range in which the strength is not weakened and the conveyance capability is not lowered. The material and thickness of the wing member 27 can be variously changed in consideration of sliding contact with the inner wall of the cleaning case 21.

M transport means S toner T transport path T1, T2 transport path U cleaning unit 8, 9 roller 10 transfer belt 21 cleaner case 22 cleaning blade 22a blade member 23 transport screw 23b, 23c spiral rib 24 seal member 25 blade facing roller 27 blade member 28 Through-hole 35 Front end surface 37a Notch 37b Notch 40 Front end lower edge (belt contact part)

JP 2008-40137 A JP 2006-259466 A JP 2006-154747 A Japanese Patent Laid-Open No. 2007-4065 JP 2005-55789 A JP 2004-61560 A JP 2004-37583 A

Claims (8)

On the belt that is wound around the upstream roller and the downstream roller , a cleaning blade that has at least a lower end edge at the front end thereof abuts from a counter direction that resists the belt traveling direction, and is disposed inside the belt. A cleaning unit comprising a blade facing roller that receives a cleaning blade via a belt,
The upper horizontal tangent of the upstream roller upstream of the blade facing roller is disposed below the upper horizontal tangent of the blade facing roller, the belt between the upstream roller and the blade facing roller, and the upstream roller The angle formed with the upper horizontal tangent is 0 ° or more, and the belt contact portion which is the lower end edge of the tip of the cleaning blade is disposed upstream of the perpendicular passing through the axis of the blade facing roller, The cleaning blade is characterized in that a tapered or convex round notch is provided at a corner between the tip surface and the top surface. A cleaner case that is scraped off by the cleaning blade and accommodates toner; and a conveying unit that conveys the toner in the cleaner case; a conveying screw that constitutes the conveying unit; The cleaning unit according to claim 1, further comprising a blade member that guides the accumulated toner toward the conveying screw . The cleaning unit according to claim 2 , wherein the blade member is substantially perpendicular to the spiral rib of the conveying screw, and a gap is provided between the blade member and the spiral rib . The cleaning unit according to claim 2 or 3, wherein the plurality of blade members are arranged at predetermined intervals along the axial direction of the conveying screw . The cleaning unit according to claim 2, wherein the blade member is provided with a through hole . The cleaning unit according to claim 2 , wherein the conveying screw includes two spiral ribs for forming two conveying paths, and a blade member is disposed only in one conveying path . The conveying screw constituting the conveying means includes two spiral ribs for forming two conveying paths, and one wing member is not provided with a wing member or a wing member provided with a through hole is provided. The cleaning unit according to claim 2 , wherein a wing member provided with a through hole is disposed in the other transport path . An image forming apparatus comprising the cleaning unit according to claim 1 .

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