JP6024312B2 - Toner conveying apparatus and printing apparatus - Google Patents

Description

The present invention relates to a toner conveying device and a printing device .

  In an electrophotographic printer, since excess toner is generated in the printing process, a waste toner transport device that transports the waste toner to a waste toner tank is provided.

  A tandem type printer usually includes four developing units, and waste toner discharged from each of the four developing units is collectively conveyed to a waste toner tank through one waste toner pipe. A screw is provided inside the waste toner pipe, and the waste toner is conveyed to a waste toner tank by the rotation of the screw. Similarly, waste toner generated from the transfer belt is discharged to a waste toner tank through the waste toner pipe.

  Since the developing units are sequentially connected to the waste toner pipe, the amount of waste toner flowing in the waste toner pipe is small upstream, but the amount of waste toner increases as going downstream. For this reason, downstream of the rotation of the screw, the transport of the waste toner may not catch up, and the waste toner may accumulate, resulting in a waste toner transport failure.

  In view of this, a technique has been proposed in which by increasing the screw pitch on the downstream side, the waste toner conveyance force is increased on the downstream side where the amount of waste toner increases, thereby preventing the waste toner from staying on the downstream side. (For example, patent document 1).

JP 2006-251114 A

In order to eliminate the retention of waste toner, there is a need for a device that reliably improves the conveyance force on the downstream side of the waste toner pipe where the amount of waste toner increases.
An object of the present invention is to provide a waste toner conveying apparatus having an increased waste toner conveying force on the downstream side.

In order to achieve the above object, the toner conveying device according to the present invention has a plurality of inlets into which toner flows in from the upstream side to the downstream side of the toner conveying, and the inlet located at the most upstream side is provided. A toner conveyance path having a larger cross-sectional area in the region corresponding to the inflow port located on the most downstream side than a cross-sectional area in the corresponding region, and a toner conveyance path provided in the toner conveyance path, for conveying toner flowing in from the inflow port first and second conveying screws, the Bei example of the second conveying screw, together with the formed shorter than the first conveying screw, located below the first transport screw In this way, the toner transport path is disposed at a position biased toward the downstream side in the toner conveyance path .
In the printing apparatus according to the present invention, a plurality of inflow ports into which toner flows in are provided from the upstream side to the downstream side of toner conveyance, and the cross-sectional area of the region corresponding to the inflow port located on the most upstream side A toner conveying path having a larger cross-sectional area in a region corresponding to the inlet located on the most downstream side, and a first and second toner conveying path that are provided in the toner conveying path and convey toner flowing in from the inlet. And the second conveying screw is formed shorter than the first conveying screw, and is positioned below the first conveying screw and in the toner conveying path. It is arranged at a position biased to the downstream side.

  According to the present invention, it is possible to provide a waste toner transport device in which the waste toner transport force on the downstream side of the waste toner transport path is increased.

1 is an external perspective view of a printer 1 that includes a waste toner conveying device 60 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view for explaining an internal configuration of the printer 1. 3 is a perspective view showing a positional relationship of a waste toner conveying device 60 with respect to a drum developing unit 14 (14m, 14c, 14y, 14k) and the like inside the printer 1. FIG. 3 is a cross-sectional view illustrating a main part of a waste toner conveyance device 60 according to the present embodiment. FIG. 6 is a cross-sectional view showing a main part of a conventional waste toner conveying device 160. FIG. 6 is a cross-sectional view showing a main part of a waste toner conveying device 60 according to another example of the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view of a printer 1 including a waste toner conveying device 60 according to an embodiment of the present invention.

  As shown in FIG. 1, the printer 1 includes a front door 3 having a handle at the front, and a paper feed cassette 4 below the front door 3. In addition, the printer 1 includes a paper discharge tray 5 on almost the entire upper surface, and a display panel 6 and an operation unit 7 on the right front side. Hereinafter, the side on which the front door 3 is provided is called the front side, and the opposite side is called the back side.

  FIG. 2 is a cross-sectional view for explaining the internal configuration of the printer 1. FIG. 2 is an internal configuration diagram of the printer 1 as viewed from the p direction on the front door 3 side in FIG. 1. The printer 1 is a tandem type color image forming apparatus of a secondary transfer system by an electrophotographic system. The printer 1 includes a toner cartridge 10, a drum developing unit 14 (14m, 14c, 14y, 14k), and a transfer belt 18 as main components.

  The toner cartridge 10 replenishes toner to a drum developing unit 14 (14m, 14c, 14y, 14k) disposed in the lower part. The four toner cartridges 10 store magenta (M), cyan (C), yellow (Y), and black (K) toners corresponding to the drum developing units 14 (14m, 14c, 14y, and 14k). Toner is replenished to each drum developing unit 14 (14m, 14c, 14y, 14k) by a toner vertical conveyance pipe 12 disposed obliquely at the bottom.

  The drum developing unit 14 (14m, 14c, 14y, 14k) is an image forming unit, and is arranged in a multistage manner by four drum developing units 14 (14m, 14c, 14y, 14k) from the left to the right in FIG. It is configured. In the following, members corresponding to the respective colors of the drum developing unit 14 (14m, 14c, 14y, 14k) are shown by adding m, y, c, k representing the color to the reference numerals.

  Of the four drum developing units 14 (14m, 14c, 14y, 14k), the three upstream drum developing units 14m, 14c, and 14y are magenta (M ), Cyan (C), and yellow (Y) color toners are formed. The drum developing unit 14k forms a monochrome image using black (K) toner mainly used for dark portions of characters and images.

  Each of the drum developing units 14 (14m, 14c, 14y, 14k) has the same configuration except for the color of the toner stored in the toner cartridge 10. Therefore, the configuration of the drum developing unit 14m will be described as an example.

  The drum developing unit 14m includes a photosensitive drum 16 at the top. The photosensitive drum 16 has a peripheral surface made of, for example, an organic photoconductive material. A charging roller, an optical writing head, a developing roller, and the like are disposed in contact with or around the periphery of the photosensitive drum 16.

  Toner is supplied from the toner cartridge 10 to each drum developing unit 14 (14m, 14c, 14y, 14k) via the toner vertical conveyance pipe 12. The toner replenished to the drum developing unit 14 (14m, 14c, 14y, 14k) is mixed with a carrier in the drum developing unit 14 and developed on the photosensitive drum 16.

  The transfer belt 18 transfers the toner image primarily transferred by the drum developing unit 14 (14m, 14c, 14y, 14k) to a printing medium such as paper (secondary transfer), and transfers the toner image to the printing medium. To the transfer position. The transfer belt 18 is an endless belt extending in a flat loop shape, and moves in the left-right direction in the figure.

  The development layer developed on the photosensitive drum 16 is transferred to the transfer belt 18, transferred to the printing medium at the secondary transfer portion, fixed to the printing medium in the fixing process, and the printed printing medium is The paper is discharged to a paper discharge tray 5 shown in FIG.

  The printer 1 includes a drum cleaning blade 20 (20m, 20c, 20y, 20k), a drum waste toner conveying screw 22 (22m, 22c, 22y, 22k), a main body waste toner conveying path 24, and a belt cleaning for waste toner processing. A blade 26, a belt waste toner conveying screw 28, a waste toner storage box 30 and the like are included.

  The drum cleaning blade 20 (20m, 20c, 20y, 20k) scrapes off the untransferred toner remaining on the photosensitive drum 16, and cleans the surface of the photosensitive drum 16. The drum cleaning blade 20 (20m, 20c, 20y, 20k) is provided on the right side of the photosensitive drum 16 of each drum developing unit 14 (14m, 14c, 14y, 14k).

  The drum waste toner conveying screw 22 (22m, 22c, 22y, 22k) removes the waste toner scraped off by the drum cleaning blade 20 (20m, 20c, 20y, 20k) from the back side (in the drawing, from the front of the drawing). It is conveyed in a direction perpendicular to the back. The drum waste toner conveying screw 22 (22m, 22c, 22y, 22k) is disposed on the right side of each photosensitive drum 16, and is provided so that the rotation axis is parallel to the rear side direction. The drum waste toner transport screw 22 (22m, 22c, 22y, 22k) is provided inside a drum waste toner transport path (not shown) for transporting drum waste toner.

  The drum waste toner conveying screw 22 is rotated by a motor (not shown) and conveys the waste toner output from each photosensitive drum 16 in the rear direction of the drum waste toner conveying path.

  The waste toner conveyance path 24 of the main body includes four drum developing units 14 (14m, 14c, 14y, 14k) conveyed to the back side of the printer 1 by drum waste toner conveyance screws 22 (22m, 22c, 22y, 22k). The waste toner for four colors is conveyed together. The main body waste toner conveyance path 24 is disposed on the back side of the printer 1 and is located on the back surface of the drum developing unit 14m, and therefore, the outer shape is indicated by a two-dot chain line.

  The belt cleaning blade 26 scrapes off the untransferred toner remaining on the transfer belt 18 and the development layer of the patch for resist adjustment. The belt cleaning blade 26 is provided on the left side of the left end of the transfer belt 18 on the left side of the drum developing unit 14m on the most upstream side.

  The belt waste toner conveying screw 28 conveys the waste toner scraped off by the belt cleaning blade 26 in the rear side direction. The belt waste toner conveyance screw 28 is provided inside a belt waste toner conveyance path (not shown) for conveying the belt waste toner. The belt waste toner conveying screw 28 is provided in the vicinity of the belt cleaning blade 26 and is provided so that the rotation shaft is parallel to the back side direction.

  The belt waste toner conveyance screw 28 is rotated by a motor (not shown) to convey the waste toner output from the photosensitive drum 16 in the belt waste toner conveyance path in the back direction. The waste toner discharge port of the belt waste toner conveyance path is connected to the main body waste toner conveyance path 24, and the belt waste toner generated from the belt is also discharged to the main body waste toner conveyance path 24.

  The waste toner storage box 30 is connected to the discharge port of the main body waste toner conveyance path 24 and stores drum waste toner generated from the photosensitive drum 16 and belt waste toner generated from the transfer belt 18 together. The waste toner storage box 30 is disposed below the left end of the printer 1 and is configured to be detachable from the printer 1 so that the accumulated waste toner can be discarded appropriately.

  Next, the waste toner conveying device 60 shown in FIG. 3 which is a feature of the present embodiment will be described. The waste toner transport device 60 transports waste toner generated from a plurality of image forming units through a transport path.

  FIG. 3 is a perspective view showing the positional relationship of the waste toner conveying device 60 with respect to the drum developing unit 14 (14m, 14c, 14y, 14k) and the like inside the printer 1. FIG. 2 is a diagram of the inside of the printer 1 as viewed from the upper right direction in FIG. 1. In the drawing, only parts necessary for the description are shown, and other parts are not shown.

  Four drum developing units 14 (14m, 14c, 14y, 14k) are arranged at regular intervals from the left so that the longitudinal direction is parallel to the back side direction. The transfer belt 18 is disposed on the four drum developing units 14 (14m, 14c, 14y, 14k).

  Of the four drum developing units 14 (14m, 14c, 14y, 14k), a waste toner storage box 30 is provided on the left side of the leftmost drum developing unit 14m. The waste toner storage box 30 is an L-shaped box as viewed from the front, and has a length over almost the whole in the rear side direction of the printer 1.

  A waste toner conveying device 60 is provided along the back side of the printer 1. A drum waste toner conveyance path of the drum developing unit 14k is connected to the right end of the waste toner conveyance device 60. The lower part (discharge port) at the left end of the waste toner conveying device 60 is connected to the waste toner storage box 30.

  The main body waste toner transport path 24 is provided with two transport paths of a first waste toner transport path 40 and a second waste toner transport path 50 in a horizontal direction. The first waste toner conveyance path 40 is provided with a length extending from the right end to the left end. The second waste toner transport path 50 has a length from the middle to the left end of the first waste toner transport path 40 and is provided below the first waste toner transport path 40.

  FIG. 5 is a cross-sectional view showing a main part of a conventional waste toner conveying device 160. Before describing the waste toner conveying device according to the present embodiment, the structure of a conventional waste toner conveying device will be briefly described.

  FIG. 5 is a diagram viewed from the same direction as the internal configuration diagram shown in FIG. 2, but in order to illustrate a conventional main body waste toner conveyance path 124 provided on the back side of the printer 1, FIG. 14 (14m, 14c, 14y, 14k), the transfer belt 18 and the like are shown in a transmissive state.

  The conventional main body waste toner conveyance path 124 is mainly formed in a pipe shape having an elongated circular cross section, and is disposed substantially horizontally on the back side of the printer 1 as described above. Inside the main body waste toner conveyance path 124, a conveyance screw 142 for conveying the waste toner is provided. The length of the conveying screw 142 is a length over almost the entire length of the main body waste toner conveying path 124. The conveying screw 142 is rotatably fitted to bearings (not shown) provided at the left and right ends inside the main body waste toner conveying path 124.

  A motor 144 for rotating the conveying screw 142 is attached to the outside of the right end of the main body waste toner conveying path 124. The shaft of the conveying screw 142 is coupled to the rotating shaft of the motor 144 directly or via a transmission member.

  Drum waste toner conveyance screws 22 (22k, 22y, 22c, 22m) are arranged in order from the right to the left with respect to the main body waste toner conveyance path 124. Since the waste toner is conveyed from the right to the left in the main body waste toner conveyance path 124, the right side is referred to as upstream and the left side is referred to as downstream in the following waste toner conveyance.

  A recovery port 166 (166k, 166y, 166c, 166m) that collects the waste toner that is transported to the back side by each drum waste toner transport screw 22 (22k, 22y, 22c, 22m) and collects in the main body waste toner transport path 124. ) Are provided as recovery ports 166k, 166y, 166c, 166m in order from the upstream. The collection ports 166 (166k, 166y, 166c, 166m) are arranged at the upper part of the main body waste toner conveyance path 124 at a constant interval in the direction of the rotation axis of the drum waste toner conveyance screw 22 (22k, 22y, 22c, 22m). Provided.

  A belt waste toner collection port 167 for collecting belt waste toner is provided further downstream of the collection port 166m of the main body waste toner conveyance path 124. The belt waste toner is transported to the back side by the belt waste toner transport screw 28 and dropped to the belt waste toner collection port 167.

  A discharge port 164 for discharging the waste toner is provided downward at the left end portion on the downstream side of the main body waste toner conveyance path 124. The waste toner conveyed to the left end, which is the most downstream by the rotation of the conveyance screw 142, falls from the discharge port 164 and is stored in the waste toner storage box 30.

  Since the drum waste toner accumulates (combines) downstream of the main body waste toner conveyance path 124, the amount of waste toner increases compared to the upstream. Further, in the vicinity of the most downstream side of the main body waste toner conveyance path 124, belt waste toner is added in addition to each drum waste toner, so that the total amount of waste toner further increases.

  As described above, in the conventional waste toner conveyance device, although the amount of waste toner increases on the downstream side, the conveyance force is almost constant from upstream to downstream. Was produced.

  FIG. 4 is a cross-sectional view showing a main part of the waste toner conveying device 60 according to the present embodiment. 4 is also a view in the same direction as the internal configuration shown in FIG. 4 shows the drum developing unit 14 (14m, 14c, 14y, 14k) in a transmissive state in order to illustrate the waste toner conveying device 60 provided on the back side of the printer 1.

  The waste toner transport device 60 includes a first waste toner transport path 40, a first transport screw 42, a first motor 44, a second waste toner transport path 50, a second transport screw 52, a second motor 54, and the like.

  As described above, the main body waste toner transport path 24 is formed of at least two waste toner transport paths of the first waste toner transport path 40 and the second waste toner transport path 50. The first waste toner conveyance path 40 is a waste toner conveyance path formed over the entire length of the main body waste toner conveyance path 24, and is disposed horizontally at a position on the back side of the printer 1. The second waste toner conveyance path 50 is a conveyance path formed on the downstream side of the main body waste toner conveyance path 24 and is provided below the first waste toner conveyance path 40.

  As described above, the main body waste toner conveyance path 24 has an elongated shape from the upstream (right end) to a middle position, and has a shape swelled downward by the second waste toner conveyance path 50 from the downstream to the left end. Yes.

  That is, the main body waste toner transport path 24 is formed so that the cross-sectional area is larger on the downstream side than on the upstream side in the waste toner transport direction. As will be described below, a plurality of corresponding conveying screws are also provided so that the number of the conveying screws increases toward the downstream side.

  In the upper part of the first waste toner conveyance path 40, collection ports for collecting waste toner are provided as collection ports 66k, 66y, 66c, 66m in order from the upstream at regular intervals. The collection ports 66k, 66y, 66c, and 66m are collection ports that collect waste toner that is transported to the back side by the drum waste toner transport screw 22 (22k, 22y, 22c, and 22m) and falls.

  Further, a belt waste toner collection port 67 is provided in the first waste toner conveyance path 40. The belt waste toner collection port 67 is formed in a cylindrical shape that protrudes upward from the upper left end of the first waste toner conveyance path 40 and extends directly below the belt waste toner conveyance screw 28.

  The first waste toner conveyance path 40 has an elongated hollow pipe shape, and the inside is formed in a substantially circular cross section. A first conveying screw 42 for conveying the waste toner is provided inside the first waste toner conveying path 40. The length of the first conveying screw 42 is substantially the entire length inside the first waste toner conveying path 40 and is a length extending from the upstream side to the downstream side. The first conveying screw 42 is rotatably supported by bearings (not shown) provided at the left and right ends of the first waste toner conveying path 40.

  A first motor 44 for rotating the first conveying screw 42 is attached outside the right end of the first waste toner conveying path 40. The shaft of the first conveying screw 42 is coupled to the rotating shaft of the first motor 44 directly or via a transmission member.

  A second waste toner conveyance path 50 is provided in a lower portion on the downstream side of the first waste toner conveyance path 40. The second waste toner transport path 50 is provided in parallel with the first waste toner transport path 40 from the position corresponding to the recovery port 66m to the left end position of the first waste toner transport path 40.

  The second waste toner conveyance path 50 is also in the shape of an elongated hollow pipe, and the inside is formed in a substantially circular cross section. Inside the second waste toner conveyance path 50, a second conveyance screw 52 for conveying the waste toner is provided. The length of the second conveying screw 52 is the length over almost the entire length of the second waste toner conveying path 50. The second conveying screw 52 is rotatably supported by bearings (not shown) provided at the left and right ends of the second waste toner conveying path 50.

  A second motor 54 for rotating the second conveying screw 52 is attached outside the right end of the second waste toner conveying path 50. The shaft of the second conveying screw 52 is coupled to the rotating shaft of the second motor 54 directly or via a transmission member.

  A partition plate 62 is provided at an appropriate interval between the second waste toner transport path 50 and the first waste toner transport path 40, and the second waste toner transport path 50 is in a range other than the partition plate 62 in the first range. The waste toner conveyance path 40 communicates with the upper and lower sides. A discharge port 64 is provided at the end (left end) of the second waste toner conveyance path 50 downward.

  The waste toner transported to the vicinity of the recovery port 66m by the first transport screw 42 and a part of the waste toner supplied from the recovery port 66m and the belt waste toner recovery port 67 are appropriately second waste toner from the upper and lower communication points. It falls on the conveyance path 50.

  As a result, in the downstream area from the recovery port 66m to the discharge port 64, waste toner flows through both the first transport screw 42 of the first waste toner transport path 40 and the second transport screw 52 of the second waste toner transport path 50. Be transported. Then, the waste toner conveyed to the left end in each of the first waste toner conveyance path 40 and the second waste toner conveyance path 50 falls from the discharge port 64 to the waste toner storage box 30 and is discharged.

  As described above, in this embodiment, waste toner from each image forming unit is sequentially discharged from the upstream side to the downstream side in the transport direction to the transport path, and the amount of waste toner increases cumulatively on the downstream side. However, in response to this, a plurality of conveying screws are provided.

  According to the embodiment described above, since the cross-sectional area of the waste toner conveyance path is increased and a plurality of conveyance screws are provided on the downstream side where the amount of waste toner increases, the waste toner conveyance force is increased downstream. Can be made. Thereby, it is possible to prevent stagnation of waste toner on the downstream side.

  Further, since the number of conveying screws is two, specifically, the conveying force of the waste toner is improved about twice, and the waste toner can be smoothly conveyed. In addition, since there are two conveying screws and the volume of the pipe is increased, the agitation effect of waste toner in the pipe can also be expected, preventing the toner from staying on the wall of the pipe, preventing toner sticking to the screw, and reducing the conveying torque. it can.

  The cross-sectional shape of the second waste toner transport path 50 may be substantially the same as the cross-sectional shape of the first waste toner transport path 40, but it may be a different shape or size.

  Further, the pitch of the blades of the second conveying screw 52 may be larger than that of the first conveying screw 42. By increasing the pitch of the blades of the second waste toner transport screw 52, the waste toner transport force on the downstream side where the waste toner increases can be further increased. Of course, the pitch of the blades of the second conveying screw 52 may be the same as that of the first conveying screw 42.

  In the above embodiment, the second waste toner conveyance path 50 is provided from the position of the fourth collection port 66m. However, the present invention is not limited to this. The actual amount of waste toner may naturally be set such that the position of the start point of the second waste toner conveyance path 50 is set to the third collection port 66c before that, or conversely the position after the collection port 66m. Depending on the situation, it may be selected appropriately.

  Further, the number of transport paths is not limited to two. For example, the total length of the transport path may be divided into three, and the transport path may be provided while being increased stepwise so that there is one upstream, two from the middle stream, and three from the downstream. In the above-described embodiment, one second waste toner conveyance path 50 is added on the downstream side, but two conveyance paths may be added on the downstream side.

  In addition, the example in which the second waste toner conveyance path 50 is provided in the lower part of the first waste toner conveyance path 40 has been described. You may do it.

  Furthermore, in the said embodiment, although the example which provides the 1st motor 44 for rotating the 1st conveyance screw 42 and the 2nd motor 54 for rotating the 2nd conveyance screw 52 was shown, it does not restrict to this. Absent. For example, the motor for rotating the first conveying screw 42 and the motor for rotating the second conveying screw 52 may be the same.

  Moreover, the 2nd conveyance screw 52 like the said embodiment does not need to be provided. For example, as shown in FIG. 6, the waste toner conveyance formed so that the cross-sectional area at the position corresponding to the most downstream collection port is larger than the cross-sectional area at the position corresponding to the most upstream collection port. The first conveying screw 42 for conveying the waste toner from the upstream side to the downstream side in the waste toner conveying path is provided in the same manner as in the above embodiment, but the number of conveying screws is not two, but the first In the waste toner conveyance path having only one conveyance screw 42 and having a large downstream sectional area, the diameter of the blade of the first conveyance screw 42 may be increased.

  As mentioned above, although embodiment of this invention was described, this invention is contained in the invention described in the claim, and its equal range. Hereinafter, the invention described in the scope of claims at the beginning of the filing of the present patent application will be added.

[Appendix 1]
A cross-sectional area at a position corresponding to the most upstream side of the recovery port has a transport path for transporting from the upstream side to the downstream side, and a plurality of recovery ports for recovering waste toner are provided from the upstream side to the downstream side. A waste toner conveyance path formed so that a cross-sectional area at a position corresponding to the recovery port on the most downstream side is larger than
A conveying screw provided in the waste toner conveying path for conveying the waste toner from the upstream side to the downstream side;
A waste toner conveying device comprising:

[Appendix 2]
The number of the transport screws in the waste toner transport path at a position corresponding to the most downstream collection port is the number of the transport screws in the waste toner transport path at a position corresponding to the most upstream recovery port. The waste toner conveying device according to appendix 1, wherein the number of conveying screws is larger than the number of conveying screws.

[Appendix 3]
The conveying screw has blades that convey the waste toner from the upstream side to the downstream side by rotation,
The conveyance screw has a first conveyance screw provided from the upstream side to the downstream side of the waste toner conveyance path, and a second conveyance screw provided on the downstream side of the waste toner conveyance path.
The waste toner conveying device according to appendix 1 or 2, wherein

[Appendix 4]
The waste toner transport path includes a first waste toner transport path having the first transport screw therein and a second waste toner transport path having the second transport screw therein, and the second waste toner transport path. 4. The waste toner transport device according to appendix 2 or 3, wherein the transport path is provided at a lower position on the downstream side of the first waste toner transport path so as to communicate with the first waste toner transport path.

[Appendix 5]
The waste toner collected from the collection port is waste toner generated from a plurality of image forming units and / or waste toner generated from a transfer belt that conveys a toner image to a transfer position to a printing medium,
Waste toner from the plurality of image forming units is sequentially discharged from the upstream side to the downstream side in the conveyance direction in the waste toner conveyance path,
The waste toner transport device according to any one of appendices 1 to 4, wherein the transport screw is provided so as to correspond to the cumulative increase in the waste toner on the downstream side.

[Appendix 6]
The waste toner conveying device according to any one of appendices 2 to 5, wherein the pitch of the blades of the second conveying screw is larger than the pitch of the blades of the first conveying screw.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, all the constituent elements shown in the embodiments may be appropriately combined. Furthermore, constituent elements over different embodiments may be appropriately combined. It goes without saying that various modifications and applications are possible without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Printer 10 Toner cartridge 12 Toner vertical conveyance pipe 14 (14m, 14c, 14y, 14k) Drum developing unit 16 Photoconductor drum 18 Transfer belt 20 (20m, 20c, 20y, 20k) Drum cleaning blade 22 (22m, 22c, 22y) 22k) Drum waste toner transport screw 24 Main body waste toner transport path 26 Belt cleaning blade 28 Belt waste toner transport screw 30 Waste toner storage box 40 First waste toner transport path 42 First transport screw 44 First motor 50 Second waste toner Conveying path 52 Second conveying screw 54 Second motor 60 Waste toner conveying device 62 Partition plate 64 Discharge port 66 (66k, 66y, 66c, 66m) Recovery port 67 Belt waste toner recovery port

Claims (5)

A plurality of inlets into which the toner flows are provided from the upstream side to the downstream side of the toner conveyance, and the inlets located on the most downstream side of the cross-sectional area of the region corresponding to the inlets located on the most upstream side are provided. A toner conveyance path having a larger cross-sectional area in the corresponding region;
First and second conveying screws provided in the toner conveying path for conveying toner flowing in from the inlet;
Bei to give a,
The second conveying screw is formed to be shorter than the first conveying screw, and is positioned below the first conveying screw and biased to the downstream side in the toner conveying path. toner conveying apparatus characterized by being arranged to. The toner conveying apparatus according to claim 1, wherein the second conveying screw is disposed so as to be parallel to the first conveying screw . The toner conveyance path includes: a first pipe that accommodates the first conveyance screw; and a second pipe that is disposed in parallel below the first pipe and accommodates the second conveyance screw. the toner conveying device according to claim 1 or 2, characterized in that. The toner conveying apparatus according to claim 3, wherein the second pipe is formed shorter than the first pipe . A plurality of inlets into which the toner flows are provided from the upstream side to the downstream side of the toner conveyance, and the inlets located on the most downstream side of the cross-sectional area of the region corresponding to the inlets located on the most upstream side are provided. A toner conveyance path having a larger cross-sectional area in the corresponding region;
First and second conveying screws provided in the toner conveying path for conveying toner flowing in from the inlet;
Bei to give a,
The second conveying screw is formed to be shorter than the first conveying screw, and is positioned below the first conveying screw and biased to the downstream side in the toner conveying path. A printing apparatus characterized by being arranged in