JP2011248027A - Waste toner conveyance mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste toner conveyance mechanism capable of efficiently conveying waste toner recovered from a toner image carrier to a recovery part.SOLUTION: The waste toner conveyance mechanism composes: a conveyance pipe 77 having a vertical conveyance path 77a leading to a bent part 77c; a rotating screw 75 that is incorporated in the conveyance pipe 77 and conveys waste toner 81 along the conveyance pipe 77; and a plurality of wedge-shaped ribs 82 formed on the inner wall of the outside portion of the bent part 77c of the conveyance pipe 77. The ribs 82 do not come into contact with the rotating screw 75 when the rotating screw 75 is conveying waste toner 81 in a normal conveyance condition, but comes in contact with fins 83 of the rotating screw 75 when the rotating screw 75 receives at its bent part 77c a pressing force in the upstream direction of conveyance due to a conveyance resistance of waste toner 81 caused by an excessively increased amount of conveyed waste toner 81 and prevents compression of the rotation screw 77, thereby preventing conveyance failure.

Description

  The present invention relates to a waste toner conveyance mechanism that efficiently conveys waste toner collected from a toner image carrier to a collection unit.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, after a toner image developed on a photosensitive drum is transferred to a sheet by a transfer unit, the remaining toner is collected by a cleaner. As the handling of the collected waste toner, there have been proposals such as first collecting in the cleaner, second collecting in a waste toner bottle, and third recycling to a developing unit for reuse. .

  However, in recent years, the first method generally employs a system in which a photosensitive drum is unitized with a developing device in recent years, and there is a problem that the volume of the unit is increased. If this increase in size is avoided, the volume of the toner container is pressed, and this causes a problem that the life of the unit is shortened.

  In addition, the second method has a problem that the replacement of the waste toner bottle is troublesome because the waste toner bottle must be replaced at an appropriate time. The third method is not suitable for use in the case of a color image forming apparatus using a total of four color toners of black and three primary colors because color mixing tends to occur.

  Therefore, a proposal has been made to recycle the waste toner collected here by effectively using the space in which the toner in the toner hopper of the developing kit of the image forming unit is consumed and vacant. (For example, refer to Patent Document 1.)

  In Patent Document 1, as a method for collecting waste toner, a transport pipe having a built-in rotating screw is used. The transport pipe is moved from a cleaner disposed below the drum kit of the image forming unit to above the toner hopper of the developing kit. The waste toner is conveyed by being drawn up to the space area to be formed.

JP 09-281866 A

  By the way, the cleaner is disposed below the image forming unit, and the space in the toner hopper is formed above the image forming unit. Therefore, the conveying pipe routed between these is at least twice. It is bent at 90 degrees. For this reason, when the waste toner is actually conveyed with this configuration, a problem of waste toner clogging often occurs.

  FIG. 6A is a cross-sectional view schematically showing the conveyance pipe routed to the side cover portion of the image forming unit in an easy-to-understand manner, and FIG. 6B shows the state of the bent portion during conveyance of waste toner. FIG. 3C is a diagram showing a state of the bent portion where the defect has occurred.

  As shown in FIG. 6A, the image forming unit 1 includes a developing kit 2 and a drum kit 3 that are engaged and supported by a side frame 4 and integrated. The cleaning blade 6 disposed in the cleaner portion 5 of the drum kit 3 scrapes off the residual toner remaining on the photosensitive drum (not visible in the drawing because it is a cross-sectional view of the side cover portion of the image forming unit).

  At the bottom of the cleaner unit 5 where the scraped-off waste toner accumulates, the rotating screw 7 is disposed so as to be exposed from the left end to the right end in the drawing. The rotary screw 7 conveys the accumulated waste toner to the right in the drawing.

  From the right end of the cleaner section 5, it is bent upward 90 degrees to form the up-and-down direction conveying section 8, further bent 90 degrees to the left and turned, and horizontally transported to the upper left end of the side cover section. A conveying pipe 13 is arranged so as to form a part 12.

  The rotating screw 7 exposed at the bottom of the cleaner unit 5 extends through the conveying pipe 13 to the upper left end of the side cover unit together with the horizontal conveying unit 12 of the conveying pipe 13. Here, the conveyance pipe 13 of the side cover portion ends, and communicates with the conveyance pipe 14 of the toner hopper 11 above the developing portion 9.

  In FIG. 9A, the transport pipe 14 of the toner hopper 11 takes over the transport of the waste toner in the direction of arrow a, and is formed above the inside of the toner hopper disposed on the side opposite to the side cover portion in the figure. The waste toner is conveyed to the waste toner container.

  In this configuration, when the rotary screw 7 is driven by the conveyance gear 15 to rotate, the waste toner 16 accumulated on the bottom of the cleaner unit 5 moves the vertical conveyance unit 8 by the arrow b as shown in FIG. Then, it is conveyed to above the side cover portion, and further conveyed to the conveying pipe 14 on the toner hopper 11 side.

  Here, the normal amount of waste toner can be conveyed without any problem. However, the waste toner 16 may adhere to the back side of the cleaning blade 6 or the inner wall surface of the cleaner unit 5, and the waste toner accumulates on this portion. Then, when vibration or the like is applied to the image forming unit 1, the accumulated waste toner 16 is peeled off from the accumulation portion and conveyed at a stroke.

  For this reason, the inside of the conveyance path becomes a waste toner excessive state. At this time, if the conveyance resistance of the waste toner 16 is larger than the conveyance force of the rotary screw 7, the rotary screw 7 is contracted in such a manner as to be pushed back to the waste toner 16 as indicated by an arrow c in FIG. .

  When the rotation screw 7 is contracted, the rotation screw 7 does not reach the end of the conveyance pipe 13, so that the conveyance cannot be taken over to the conveyance pipe 14 on the toner hopper 11 side, resulting in toner conveyance failure and waste toner clogging. There is a problem to be solved that occurs and causes a failure of the image forming unit 2.

  As a countermeasure, it is conceivable to increase the spring force of the rotary screw 7 so that “waste toner transport resistance” <“screw transport force”. However, since the rotary screw 7 is rotating while being bent in the transport pipe 13, stress is generated in the rotary screw 7 in the bent portion.

  Therefore, if the spring force of the rotary screw 7 exceeds the stress coefficient with the radius of curvature of the transport pipe 13 as a constant, the rotary screw 7 will break before the image forming unit 2 reaches the end of its life due to fatigue. . For this reason, there is a restriction that the spring force cannot be increased beyond a certain value.

  For this reason, forcible vibration is applied to the image forming unit 2 before the toner conveyance failure occurs, or the disassembly function of the apparatus is enhanced so that it can be recovered immediately by maintenance work when waste toner clogging occurs. Though considered, the problem remains that these are not essential solutions.

  In order to solve the above-described problems, a waste toner transport mechanism according to the present invention includes a transport pipe including a vertical transport path that follows a bent portion, and a rotation that is built in the transport pipe and transports waste toner along the transport pipe. A screw and a plurality of wedge-shaped ribs formed on the outer inner wall of the bent portion of the conveying pipe, and the rib is used when the rotating screw is conveying the waste toner in a normal conveying state. Does not come into contact with the rotating screw, and when the waste toner is transported excessively, the rotating screw receives a compressive force in the upstream direction of conveyance at the bent portion due to the conveyance resistance of the waste toner. It is comprised so that it may contact | abut to the fin of this and the compression of the said rotation screw may be prevented.

  The transport pipe is provided, for example, on the side cover side of the drum kit of the image forming unit constituted by the developing kit and the drum kit, and is disposed above the waste toner discharge port at the horizontal end of the cleaner unit of the drum kit. A vertical conveyance path bent by 90 degrees and a horizontal conveyance path bent by 90 degrees and turned are formed.

  In this case, for example, the end of the horizontal conveyance path is configured to communicate with the beginning of the conveyance pipe on the development kit side.

  According to the present invention, the wedge-shaped rib provided on the outer inner wall of the conveying pipe is a fin of the rotating screw even if the rotating screw receives a compressive force at the conveying portion in the vertical direction of the conveying pipe due to the conveying resistance of the waste toner that has been excessively conveyed. Prevents the rotating screw from being compressed, and even with a screw with weak spring force, the waste toner can be transported stably without contraction, which eliminates the occurrence of failure of the image forming unit due to waste toner clogging. The effect that it is done.

1 is an external perspective view of a full-color image recording apparatus (printer) including a waste toner conveyance mechanism according to Embodiment 1 of the present invention. 2 is a cross-sectional view illustrating an internal configuration of a printer including a waste toner conveyance mechanism according to Embodiment 1. FIG. FIG. 3 is a perspective view illustrating an external appearance of only one image forming unit including the waste toner conveyance mechanism according to the first exemplary embodiment. FIG. 4 is a cross-sectional view of the image forming unit shown in FIG. 3. (a) is a cross-sectional view schematically showing a transport pipe routed in the side cover and a rotating screw that is exposed in the cleaner and extends from the start end to the end of the transport pipe, and (b) shows waste toner. (C) is an enlarged view of the lower bent portion, (d) is a cross-sectional view of the up-down direction conveyance path for conveying excessive waste toner, and (e) is the lower part of the cross-sectional view of the up-down direction conveyance path during conveyance. It is an enlarged view of a bending part. (a) is a cross-sectional view schematically showing a conveyance pipe routed to a side cover portion of a conventional image forming unit in an easy-to-understand manner, (b) is a diagram showing a state of a bent portion during conveyance of waste toner, (c) ) Is a diagram showing a state of a bent portion where a defect has occurred.

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

  FIG. 1 is an external perspective view of a full-color image recording apparatus (hereinafter simply referred to as a printer) provided with a waste toner conveying mechanism according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the printer 20 includes a front door 22 having a handle 21 at the front, and includes two sheet cassettes 23 that are divided into upper and lower stages below the front door 22. A discharge tray 24 is provided on almost the entire upper surface, and a display panel 25 and an operation unit 26 are provided on the right front side.

  FIG. 2 is a cross-sectional view illustrating the internal configuration of the printer. The printer 30 shown in FIG. 2 is an electrophotographic and secondary transfer tandem type color image forming apparatus, and includes an image forming unit 32, an intermediate transfer belt unit 33, a paper feeding unit 34, and a duplex printing transport unit 35. It consists of

  The image forming section 32 has a configuration in which four image forming units 36 (36M, 36C, 36Y, 36K) are arranged side by side in a multistage manner from right to left in FIG.

  Of the four image forming units 36, three image forming units 36M, 36C, and 36Y on the upstream side (right side in the figure) are magenta (M), cyan (C), and yellow (subtractive three primary colors), respectively. A mono-color image is formed with the color toner of Y), and the image forming unit 36K forms a monochrome image with the black (K) toner mainly used for characters and dark portions of the image.

  Each of the image forming units 36 has the same configuration except for the color of toner stored in a toner container (toner cartridge). Therefore, the configuration of the black (K) image forming unit 36K will be described below as an example.

  The image forming unit 36 includes a photosensitive drum 37 at the bottom. The peripheral surface of the photosensitive drum 37 is made of, for example, an organic photoconductive material. A cleaner 38, a charging roller 39, an optical writing head 41, and a developing roller 43 of the developing device 42 are arranged around the periphery of the photosensitive drum 37.

  The developing unit 42 applies magenta (M), cyan (C), yellow (Y), or black (K) toner to the upper toner container as indicated by M, C, Y, and K in FIG. An intermediate portion is provided with a toner replenishing mechanism for the lower portion.

  In addition, the developing roller 43 is provided at the lower side of the developing unit 42 in the side opening, and a toner stirring member, a toner supply roller 49 for supplying toner to the developing roller 43, and a toner layer on the developing roller 43 are fixed. A doctor blade that regulates the layer thickness is provided.

  The intermediate transfer belt unit 33 has an endless transfer belt 44 extending in a flat loop shape from substantially the left and right sides of the drawing at approximately the center of the main body device, and the transfer belt 44 is stretched over the transfer belt 44. A driving roller 45 and a driven roller 46 are provided to circulate and move the belt 44 counterclockwise in the figure.

  The transfer belt 44 transfers the toner image directly to the belt surface (primary transfer) and conveys the toner image to the transfer position to the paper for further transfer (secondary transfer). The whole is called an intermediate transfer belt unit.

  The intermediate transfer belt unit 33 includes a belt position control mechanism 47 in the loop of the flat loop-shaped transfer belt 44. The belt position control mechanism 47 includes a primary transfer roller 48 made of a conductive foam sponge that presses against the lower peripheral surface of the photosensitive drum 37 via the transfer belt 44.

  The belt position control mechanism 47 has three primary transfer rollers 48 corresponding to the three image forming units 36M, 36C, and 36Y of magenta (M), cyan (C), and yellow (Y) as vertical support shafts. Rotate to the center with the same period.

  Then, the belt position control mechanism 47 rotates and moves one primary transfer roller 48 corresponding to the black (K) image forming unit 36K with a rotational movement period different from the period of the three primary transfer rollers 48. The belt 44 is moved away from the photosensitive drum 37.

  That is, the belt position control mechanism 47 determines the position of the transfer belt 44 of the intermediate transfer belt unit 33 in the full color mode (all four primary transfer rollers 48 are in contact with the transfer belt 44), monochrome mode (in the image forming unit 36K). Only the corresponding primary transfer roller 48 is in contact with the transfer belt 44) and all non-transfer modes (all four primary transfer rollers 48 are separated from the transfer belt 44).

  In the intermediate transfer belt unit 33, a belt cleaner unit is disposed further upstream of the image forming unit 36M on the uppermost stream side in the belt movement direction on the upper surface, and is flat and thin so as to be almost along the entire lower surface. The waste toner collecting container 51 is detachably disposed.

  The paper feed unit 34 includes two paper feed cassettes 23 arranged in two upper and lower stages as shown in FIG. 1, and near the paper feed opening (right side in the figure) of the two paper feed cassettes 23. A sheet take-out roller 52, a feeding roller 53, a separating roller 54, and a standby conveyance roller pair 55 are disposed.

  In the paper conveyance direction (vertical upward direction in the figure) of the standby conveyance roller pair 55, a secondary transfer roller 56 that is in pressure contact with the driven roller 46 via the transfer belt 44 is disposed, and the secondary transfer portion to the paper is arranged. Forming.

  A belt-type thermal fixing device 57 is disposed downstream (upward in the drawing) of the secondary transfer portion, and the belt after the fixing of the belt-type thermal fixing device 57 is further downstream of the belt-type thermal fixing device 57. And a pair of discharge rollers 61 for discharging the discharged paper to a paper discharge tray 24 formed on the upper surface of the apparatus.

  The duplex printing transport unit 35 includes a start return path 62a branched from the intermediate transport path between the carry-out roller pair 58 and the discharge roller pair 61 in the right lateral direction in the figure, and then an intermediate return path 62b that bends downward. A terminal return path 62c that bends in the left lateral direction opposite to the above and eventually reverses the return sheet, and four return roller pairs 63a, 63b, 63c, and 63d arranged in the middle of these return paths. ing.

  The exit of the end return path 62c communicates with a conveyance path to the standby conveyance roller pair 55 corresponding to the sheet feeding cassette 23 below the sheet feeding section 34. In this example, a cleaning unit 65 is disposed on the upper surface of the intermediate transfer belt unit 33.

  The cleaning unit 65 abuts on the upper surface of the transfer belt 44 and scrapes off and removes the waste toner. The cleaning unit 65 collects the waste toner in a temporary storage unit of a belt cleaner unit (not shown). The inside is conveyed to the upper part, and sent to the waste toner collecting container 51 through a dropping cylinder.

  As shown in FIG. 2, the image forming apparatus 1 does not directly transfer a toner image onto a conventional sheet, but an intermediate transfer belt on a sheet that is vertically conveyed by a standby conveyance roller pair 55 to a secondary transfer unit. The toner image is transferred via 44.

  Therefore, in the maintenance process for recovering from a problem such as a paper jam occurring in the paper conveyance path, it is possible to deal with it by simply opening the right side of FIG.

  Since troubles such as a paper jam do not occur in the arrangement portion of the kits, the operation of attaching / detaching consumables such as kits concentrated on the left side of FIG. 2 is performed by opening the front door 22 and exchanging in the longitudinal direction. It is configured to be good with just a small space.

  Thereby, the dimension between kits is reduced as much as possible, and size reduction of the whole apparatus main body is achieved. Further, the optical writing head 41 itself is also downsized, and is configured to be closer to the photosensitive drum 37.

  FIG. 3 is a perspective view showing the appearance of only one image forming unit 36 taken out. As shown in FIG. 3, the image forming unit 36 includes a developing kit 42 that is held by the exterior frame 66 and a drum kit 67 that is integrated with the developing kit 42 and is held by the exterior frame 66. .

  The drum kit 67 is formed with an elongated groove-like long hole 68, and the upper surface of the photosensitive drum 37 is positioned below the long hole 68. When the image forming unit 36 is installed in the printer main body, the light emitting portion at the tip of the optical writing head 41 is positioned in the long hole 68, and preparation for image formation is completed.

  Further, a side cover 69 is provided which rises in the vertical direction from the lower part of the drum kit 67 (the lower part of the cleaner 38 in FIG. 2) and extends in the horizontal direction along the developing kit 42. A conveyance pipe, which will be described later, is disposed inside the side cover 69.

  FIG. 4 is a cross-sectional view of the image forming unit 36 described above. As shown in FIG. 4, the photosensitive drum 37, the cleaner 38, and the charging roller 39 shown in FIG. 2 are integrated as a drum kit 67 into the exterior frame 66 integrally with the developing kit 42.

  The developing kit 42 is divided into an upper toner hopper 71 and a lower developing tank 72. The toner hopper 71 includes a toner supply unit 73 in a lower part connected to the developing tank 72. When the amount of toner in the developing tank 72 becomes a predetermined amount or less, a toner supply port (not shown) of the toner supply unit 73 is opened. Then, the toner is supplied to the developing tank 72.

  In addition to the developing roller 43 and the supply roller 49 already described, the toner tank supplied from the supply roller 49 onto the developing roller 43 has a constant thickness. A doctor blade and a stirring member are provided.

  Further, the drum kit 67 includes a cleaning blade 74 that contacts the photosensitive drum 37 in the cleaner 38, and includes a rotary screw 75 exposed at the bottom of the cleaner and a conveying gear 76 that rotationally drives the rotary screw 75. Yes.

  The portion of the rotary screw 75 exposed in the cleaner 38 is composed of a screw shaft directly connected to the conveyance gear 76 and a fin that is integrally formed with the screw shaft and rotates. Consists of.

  The rotary screw 75 (that is, the fin) is disposed in a transport pipe 77 in a side cover 69 that rises from the end of the cleaner 38 and extends in the horizontal direction (the depth direction in FIG. 4) along the development kit 42. It is connected integrally with the fin.

  The end of the transport pipe 77 communicates with a kit connection transport pipe, which will be described later, which is not visible in FIG. 4, which is connected to a lower opening transport pipe 78 disposed above the toner hopper 71.

  FIG. 5A is a cross-sectional view schematically showing a conveying pipe 77 routed in the side cover 69 and a rotating screw 75 that is exposed in the cleaner 38 and extends from the start end to the end of the conveying pipe 77. FIG. 5 (b) is a cross-sectional view of the up-down direction conveyance path for conveying waste toner, FIG. 5 (c) is an enlarged view of the lower bent portion thereof, and FIG. 5 (d) is a diagram showing waste toner in an excessive state. Sectional drawing of the up-down direction conveyance path in conveyance, FIG.5 (e) is an enlarged view of the lower bending part.

  In FIG. 5A, the same components as those shown in FIGS. 2 to 4 are denoted by the same reference numerals as those shown in FIGS. The lower part of the developing kit 42 is behind the drum kit 67 in FIG.

  As shown in FIG. 5 (a), a rotary screw 75 is exposed from the left end portion to the right end portion of the cleaner 38 where waste toner is accumulated. The rotary screw 75 is driven to rotate by the conveying gear 76 and conveys the waste toner accumulated on the bottom of the cleaner 38 toward the left end in the drawing.

  From the left end of the cleaner 38, as shown in FIGS. 3 and 4, the side cover 69 is bent upward by 90 degrees to rise to form a vertical side cover, and further bent by 90 degrees to the left. It turns to form a horizontal side cover along the upper end of the toner hopper 71 of the developing kit 42 to the left end.

  Arranged inside the side cover, the conveying pipe 77 forms a vertical conveying path 77a and a horizontal conveying path 77b. A rotary screw 75 exposed at the bottom of the cleaner 38 enters the transport pipe 77 and extends through the vertical transport path 77a to the end of the horizontal transport path 77b.

  The end of the horizontal conveyance path 77b of the conveyance pipe 77 communicates with the start end of the kit connection conveyance pipe 79 connected to the lower opening conveyance pipe 78 of the toner hopper 71 shown in FIG. The waste toner that has been carried out of the cleaner 38 by the rotating screw 75, conveyed in the vertical conveyance path 77a, and conveyed to the end of the horizontal conveyance path 77b is pulled to the kit connection conveyance pipe 79.

  FIG. 5B is a cross-sectional view of the vertical conveyance path 77a that conveys a normal amount of waste toner 81. As shown in the enlarged view of FIG. 5 (c), a plurality (four in the illustrated example) of wedge-shaped ribs 82 are formed on the outer inner wall of the lower bent portion 77c of the vertical conveyance path 77a.

  If such a conveyance pipe 77 is injection-molded into a vertically divided shape, and the two parts are bonded together to form a pipe, a wedge-shaped rib 82 is formed on the inner wall of one of the two parts (the outer side of the bent portion). It is easy to do.

  When the normal amount of waste toner 81 shown in FIG. 5 (b) is being conveyed, the rotary screw 75 is attracted to the inside of the bent portion due to friction between the fin 83 and the conveyance pipe 77 due to the rotation of the rotary screw 75. The fin 83 does not contact the rib 82.

  In this configuration, the waste toner 81 adhering to the back side of the cleaning blade 74 and the inner wall surface of the cleaner 38 is peeled off from the adhering portion by, for example, vibration of the image forming unit 36 and is conveyed at once by the rotating screw 75 of the exposed portion. Then, as shown in FIG. 5D, the waste toner 81 in the up-down direction conveyance path 77a becomes excessive.

  However, in this example, as shown in the enlarged view of FIG. 5E, even if the rotary screw 75 in the vertical conveyance path 77a receives a downward compression force due to the conveyance resistance of the waste toner 81 that has become excessive, as shown in FIG. Since the rotary screw 75 pushed downward is pushed outward at the bent portion, the fin 83 engages with the rib 82 and the fin 83 is supported by the rib 82 as shown by being surrounded by a circle e. Is not compressed downward.

  Therefore, the entire length of the rotary screw 75 is not shortened, so that the waste toner 81 can be transported to the end of the horizontal transport path 77b, and the transport of the waste toner 81 to the kit connection transport pipe 79 is taken over at the end. Can do.

  As described above, according to this embodiment, even if the waste toner 81 is excessive in the vertical conveyance path 77a, the rotation screw 75 is not contracted to cause a conveyance failure, and the image forming unit 36 or the like is broken. Is prevented.

  The present invention can be used in a waste toner transport mechanism that efficiently transports waste toner collected from a toner image carrier to a collection unit.

DESCRIPTION OF SYMBOLS 1 Image forming unit 2 Developing kit 3 Drum kit 4 Side frame 5 Cleaner part 6 Cleaning blade 7 Rotating screw 8 Vertical conveyance part 9 Developing part 11 Toner hopper 12 Horizontal conveyance part 13, 14 Conveying pipe 15 Conveying gear 16 Waste toner 20 Printer 21 Handle 22 Front door 23 Paper feed cassette 24 Paper discharge tray 25 Display panel 26 Operation part 30 Printer 32 Image forming part 33 Intermediate transfer belt unit 34 Paper feed part 35 Double-sided printing transport unit 36 (36M, 36C, 36Y, 36K) ) Image forming unit 37 Photosensitive drum 38 Cleaner 39 Charging roller 41 Optical writing head 42 Developing kit 43 Developing roller 44 Transfer belt 45 Drive roller 46 Driven roller 47 Belt position control mechanism 48 Primary transfer roller 49 Roller 51 Waste toner collecting container 52 Paper take-out roller 53 Feed roller 54 Rolling roller 55 Standby transport roller pair 56 Secondary transfer roller 57 Belt-type heat fixing device 58 Unloading roller pair 61 Discharge roller pair 62a Start return path 62b Intermediate return path 62c End return path 63a, 63b, 63c, 63d Return roller pair 65 Cleaning section 66 Exterior frame 67 Drum kit 68 Long hole 69 Side cover 71 Toner hopper 72 Developer tank 73 Toner supply section 74 Cleaning blade 75 Rotating screw 76 Conveying gear 77 Conveyance Pipe 77a Vertical conveyance path 77b Horizontal conveyance path 78 Lower opening conveyance pipe 79 Kit connection conveyance pipe 81 Waste toner 82 Rib 83 Fin

Claims (3)

A transport pipe including a vertical transport path following the bent portion;
A rotating screw built in the transport pipe for transporting waste toner along the transport pipe;
A plurality of wedge-shaped ribs formed on the outer inner wall of the bent portion of the transport pipe;
Have
The rib does not come into contact with the rotating screw when the rotating screw is conveying the waste toner in a normal conveying state, and an excessive amount of the waste toner is transported due to the transport resistance of the waste toner. When the rotary screw receives a compressive force in the conveyance upstream direction at the bent portion, the rotary screw comes into contact with a fin of the rotary screw to prevent the rotary screw from being compressed.
A waste toner conveying mechanism characterized by the above.   The transport pipe is provided on the side cover side of the drum kit of the image forming unit including the developing kit and the drum kit, and is 90 degrees upward from the waste toner discharge port at the horizontal end of the cleaner unit of the drum kit. 2. The waste toner conveying mechanism according to claim 1, wherein a bent vertical conveying path and a horizontal conveying path bent by 90 degrees and turned are formed.   3. The waste toner transport mechanism according to claim 2, wherein the end of the horizontal transport path communicates with a start end of a transport pipe on the development kit side.