WO2019083240A1

WO2019083240A1 - Waste toner transport device with elongation apparatus

Info

Publication number: WO2019083240A1
Application number: PCT/KR2018/012514
Authority: WO
Inventors: Katsushi HIGASHIDA
Original assignee: Hp Printing Korea Co., Ltd.
Priority date: 2017-10-27
Filing date: 2018-10-23
Publication date: 2019-05-02
Also published as: JP2019078980A

Abstract

A waste toner transport device includes a housing to collect a waste toner, a waste toner transport member disposed in the housing, and an elongation apparatus located at one axial end of the waste toner transport member. The waste toner transport member transports the waste toner, and the elongation apparatus elongates the waste toner transport member in an axial direction. The elongation apparatus is switched between an elongated state, in which the waste toner transport member is elongated, and a contracted state in which the elongation of the waste toner transport member is relaxed.

Description

WASTE TONER TRANSPORT DEVICE WITH ELONGATION APPARATUS

Imaging systems may utilize a developer containing a toner to form an image on a printing medium. The toner is contained in a tank and carried to a photosensitive body at the time of forming the image. The toner is transferred from the photosensitive body to the printing medium, but part of the toner remains on the photosensitive body. The remaining toner is collected by a cleaning device as a waste toner.

FIG. 1 is a schematic construction view of an example image forming apparatus;

FIG. 2 is an exploded perspective view of an example waste toner transport device;

FIG. 3 is a cross-sectional view illustrating the internal structure of the example waste toner transport device of FIG. 2;

FIG. 4 illustrates the example waste toner transport device of FIG. 2 in a state in which a shutter of the waste toner transport device is closing off a discharge port;

FIG. 5(a) is a drawing illustrating the example waste toner transport device in a state in which the shutter of FIG. 4 has closed off the discharge port;

FIG. 5(b) illustrates an example waste transport device without a waste toner collection container;

FIG. 6 is a drawing illustrating the example waste toner transport device in a state in which the shutter of FIG. 4 has opened the discharge port;

FIG. 7(a) is a drawing illustrating the example waste toner transport device in a state in which the shutter of FIG. 4 has closed off the discharge port, viewed from a direction different than FIG. 6; and

FIG. 7(b) illustrates an example waste transport device without a waste toner collection container.

In the following description, with reference to the drawings, the same reference numbers are assigned to the same components or to similar components having the same function, and overlapping description is omitted.

A toner transport device may be provided with a process cartridge unit. The toner transport device may include a transport path in which a waste toner is transported, a screw-shaped transport member disposed within the transport path for transporting the waste toner, and a drive source for rotating the transport member. The transport path may include a first transport path positioned outside the process cartridge unit, and a second transport path provided inside the process cartridge unit.

When the transport member is driven by the drive source and rotated, the toner inside the second transport path may be transported toward the first transport path, and the toner is discharged to the outside of the toner transport device through the first transport path. The transport member may have a shaft extending along the transport path, and a helical member helically extending in the direction along which the shaft extends. The helical member may be fixed to the shaft at three or more positions, including the ends and a portion located between the ends.

In some toner transport devices in which the helical member is prolonged along the transport path, slack may be caused in the helical member and, because of the slack, the helical member may come in contact with an inner wall surface of the transport path. When the helical member rotates in contact with the inner wall surface, noise may arise from the contact between the helical member and the inner wall surface.

An example waste toner transport device for an image forming apparatus, as discloses herein, may be configured to suppress the generation of noise.

The example waste toner transport device may include a first housing for collecting a waste toner, a screw-shaped waste toner transport member disposed in the first housing for stirring and transporting the waste toner, and a screw elongation apparatus at one axial end of the waste toner transport member for elongating the waste toner transport member in the axial direction. The screw elongation apparatus may be switched between an elongated state, in which the waste toner transport member is elongated, and an elongation released (e.g., contracted) state in which the elongation of the waste toner transport member is released (e.g., allowed to contract or return to a non-elongated state).

The waste toner transport device may include the first housing for collecting the waste toner, and the screw-shaped waste toner transport member is disposed in the first housing. The waste toner transport member can be elongated by the screw elongation member provided at one axial end of the waste toner transport member. In some examples, when the waste toner transport member is elongated by the screw elongation member, slackening of the waste toner transport member can be suppressed and the posture of the waste toner transport member can be stabilized. Accordingly, the suppression of slackening of the waste toner transport member can suppress contact of the waste toner transport member with inner wall surfaces of the associated components, and the generation of noise caused by contact of the waste toner transport member can thus be suppressed.

Further, maintaining the waste toner transport member in the tensioned state for an extended period of time may result in deformation or creep in components supporting the waste toner transport member. However, the screw elongation member may be switched between the elongated state, in which the waste toner transport member is elongated, and the elongation released state in which the elongation of the waste toner transport member is released. As a result, deformation or creep can be suppressed.

The waste toner transport member can be elongated and contracted in the axial direction, and the outer diameter of the waste toner transport member, upon elongation of the waste toner transport member, may be smaller than the inner diameter of the first housing. In this case, the outer diameter of the waste toner transport member elongated in the axial direction is smaller than the inner diameter of the first housing. As a result, contact of the elongated waste toner transport member with the inner wall surface of the first housing can be suppressed, and the occurrence of noise in the elongated state can also be suppressed.

Further, the screw elongation apparatus may include a second housing for receiving the waste toner stirred and transported by the waste toner transport member, and an open and close member for opening and closing a waste toner discharge port to the second housing. The screw elongation apparatus may elongate the waste toner transport member when the discharge port is opened by the open and close member, and may release the elongation of the waste toner transport member when the discharge port is closed off by the open and close member. In some examples, the elongation of the waste toner transport member by the screw elongation apparatus and the opening or closing of the discharge port may be coordinated.

Further, the waste toner transport member may be elongated under a state where the discharge port is opened and the waste toner transport device is operated to allow for receiving the waste toner. Also, the elongation of the waste toner transport member may be released under a state where the waste toner transport device is rested and the discharge port is closed off. Consequently, the waste toner transport member can be elongated when the waste toner can be discharged through the discharge port and the elongation may be released when the discharge is not available. In this manner, switching between the elongated state and the elongation released state may be performed.

The screw elongation device may include an axially movable screw support member which supports one axial end of the waste toner transport member. The open and close member may be rotated around the axis of the waste toner transport member for opening and closing the discharge port. When the open and close member is rotated to open the discharge port, the screw elongation apparatus may push out the screw support member axially for elongating the waste toner transport member. In this case, the rotary open and close member may be used as the screw elongation apparatus.

Further, the screw elongation apparatus elongates the waste toner transport member by pushing out the screw support member when the discharge port is opened by the rotation of the open and close member. Accordingly, the rotary operation of the open and close member and the elongation and contraction of the waste toner transport member may be coordinated. Consequently, when the rotary open and close member is used, the waste toner transport member may be switched between the elongated state and the elongation released state.

The waste toner transport device may be provided with an elastic body between the open and close member and a duct extending from the first housing and formed with the discharge port. In some examples, the elastic body may be configured to urge the open and close member in a direction to close off the discharge port. In this case, the elastic body urges the open and close member in the direction to close off the discharge port. As a result, the elongation of the waste toner transport member is released as the open and close member performs closing, and a transition to the elongation released state can be made without relying on the elongation of the waste toner transport member. As such, the transition to the elongation released state can be made due to urging by the elastic body, and a deformation or failure of the components due to creep can be suppressed.

Further, a gear unit for rotating the waste toner transport member may be provided at an end of the waste toner transport member opposite to the screw elongation apparatus. Upon rotation, the gear unit may elongate the waste toner transport member in a direction opposite to the direction of elongation of the screw elongation apparatus. In this case, as the waste toner transport member is pulled in a direction opposite to the screw elongation apparatus during rotation of the gear unit, the amount of tensioning of the waste toner transport member can be made larger. Consequently, slackening of the waste toner transport member and contact of the waste toner transport member with the inner wall surfaces can be suppressed.

Further, the gear unit may elongate the waste toner transport member during rotation in the aforementioned elongated state. In this case, as the gear unit is rotated to pull the waste toner transport member while the waste toner transport member is being elongated by the screw elongation apparatus, slackening of the waste toner transport member can be suppressed further during the rotation of the gear unit.

An example image forming apparatus may therefore be provided with the aforementioned waste toner transport device.

An example image forming apparatus 1 may be configured to form color images using magenta, yellow, cyan and black colors. As illustrated in FIG. 1, the image forming apparatus 1 is provided with a recording medium conveyance unit 10 for conveying a paper sheet P, developing devices 20 for developing electrostatic latent images, and a transfer unit 30 for secondarily transferring a toner image to the paper sheet P. Additionally, the image forming apparatus 1 includes photosensitive drums 40 (e.g., electrostatic latent image carriers) on circumferential surfaces of which the images are formed, and a fixing unit 50 for fixing the toner image onto the paper sheet P.

The recording medium conveyance unit 10 contains the paper sheet P, i.e., a recording medium on which image is to be formed, and conveys the paper sheet P along a conveyance path R1. The paper sheet P is stacked and contained in a cassette K. The recording medium conveyance unit 10 conveys the paper sheet P to a secondary transfer region R2 through the conveyance path R1 in such a timing that a toner image to be transferred to the paper sheet P arrives at the secondary transfer region R2.

In some examples, four developing devices 20 are provided, one for each of the respective colors. Each of the developing devices 20 is provided with a developer roller 21 for carrying toner to the photosensitive drum 40. In the developing device 20, the toner and carrier are adjusted at a desired mixing ratio, and mixed and stirred to disperse the toner uniformly so as to prepare a developer imparted with an amount of charge. The developer is carried by the developer roller 21. As the developer roller 21 rotates to carry the developer to a region opposing the photosensitive drum 40, toner is moved out of the developer carried on the developer roller 21 and onto the electrostatic latent image formed on the circumferential surface of the photosensitive drum 40 to develop the electrostatic latent image. Further, in the developing device 20, a trickle development scheme is employed for maintaining the charge amount of the contained developer constant, according to which scheme a carrier is supplied into a toner tank N together with the toner during a toner replenishing operation, and a developer which is deteriorated in the developing device 20 is discharged. In the developing device 20, the deteriorated developer is collected in a waste toner collection device.

The transfer unit 30 carries the toner image formed with the developing device 20 to the secondary transfer region R2 where the toner image is secondarily transferred to the paper sheet P. The transfer unit 30 is provided with a transfer belt 31,

support rollers

31a, 31b, 31c and 31d for supporting the transfer belt 31, primary transfer rollers 32 for holding the transfer belt 31 with the photosensitive drums 40, and a secondary transfer roller 33 for holding the transfer belt 31 with the support roller 31d.

The transfer belt 31 is an endless belt circularly moved by the

support rollers

31a, 31b, 31c and 31d. The primary transfer rollers 32 are disposed to press against the photosensitive drums 40 from the inside of the transfer belt 31. The secondary transfer roller 33 is disposed to press against the support roller 31d from the outside of the transfer belt 31.

Four photosensitive drums 40 are provided, one for each of the respective colors. The four photosensitive drums 40 are provided along the direction of movement of the transfer belt 31. Around the circumference of the photosensitive drum 40, the developing device 20, a charge roller 41, an exposure unit 42 and a waste toner transport device 70 including a cleaning unit are arranged. The waste toner transport device 70 will be described in further detail later.

The charge roller 41 uniformly charges the surface of the photosensitive drum 40 at a predetermined potential. The exposure unit 42 exposes the surface of the photosensitive drum 40 charged by the charge roller 41 in accordance with an image to be formed on the paper sheet P. The potential of portions of the surface of the photosensitive drum 40 exposed by the exposure unit 42 is thereby changed to form an electrostatic latent image. The four developing devices 20 each uses the toner supplied from the toner tank N provided opposite to the developing device 20 to develop the electrostatic latent image formed on the photosensitive drum 40 and to create a toner image. The toner tanks N are respectively filled with magenta, yellow, cyan and black toners, together with the carrier.

The fixing unit 50 adheres and fixes onto the paper sheet P the toner image that has been secondarily transferred from the transfer belt 31 to the paper sheet P. The fixing unit 50 is provided with a heater roller 51 for heating the paper sheet P and a pressure roller 52 for pressing the heater roller 51. The heater roller 51 is formed in a cylindrical shape, and the heater roller 51 is internally provided with a heat source such as a halogen lamp. A contact area called a fixing nip is formed between the heater roller 51 and the pressure roller 52, and the toner image is fused and fixed onto the paper sheet P while the paper sheet P is passed through the fixing nip. Further, the image forming apparatus 1 is provided with

discharge rollers

61 and 62 for discharging the paper sheet P on which the toner image has been fixed with the fixing unit 50 to the outside of the apparatus.

Next, an example operation of the image forming apparatus 1 is described. When an image signal of a recording image is input to the image forming apparatus 1, a controller of the image forming apparatus 1 uniformly charges the surface of the photosensitive drum 40 at a predetermined potential by the charge roller 41, based on the received image signal. After that, an electrostatic latent image is formed on the surface of the photosensitive drum 40 by irradiating laser light with the exposure unit 42.

In the developing device 20, the electrostatic latent image is developed to form a toner image. The toner image is initially transferred from the photosensitive drum 40 to the transfer belt 31 in the region at which the photosensitive drum 40 and the transfer belt 31 are opposed. The toner images formed on the four photosensitive drums 40 are successively overlaid to form a single overlaid toner image on the transfer belt 31. Then, the overlaid toner image is secondarily transferred onto the paper sheet P conveyed from the recording medium conveyance unit 10 in the secondary transfer region R2 at which the support roller 31d and the secondary transfer roller 33 are opposed. The paper sheet P, with the secondarily transferred overlaid toner image, is conveyed to the fixing unit 50. The overlaid toner image is fused and fixed onto the paper sheet P while the paper sheet P is made to pass under heat and pressure between the heater roller 51 and the pressure roller 52. After that, the paper sheet P is discharged to the outside of the image forming apparatus 1 by the

discharge rollers

61 and 62.

Next, the waste toner transport device 70 will now be described. As illustrated in FIG. 2, the waste toner transport device 70 is provided with a cleaning blade 71. The cleaning blade 71 collects the toner remaining on the photosensitive drum 40, after the toner image formed on the photosensitive drum 40 has been initially transferred to the transfer belt 31.

As illustrated in FIG. 2 and FIG. 3, the waste toner transport device 70 includes a housing 72 (first housing) for containing the waste toner collected by the cleaning blade 71, a screw-shaped coil auger 73 (waste toner transport member) for transporting the waste toner in the housing 72, a gear unit 74 for rotating the photosensitive drum 40 and the coil auger 73, and a cylindrical duct 75 extending from the housing 72 opposite to the gear unit 74.

The housing 72 is in the form of a box extending in an axial direction D of the photosensitive drum 40. The axial direction D is a direction along which the photosensitive drum 40 and the screw-shaped coil auger 73 extend, and coincides with the direction along which a virtual rotational axis L of the coil auger 73 extends. The housing 72 receives the waste toner scraped off by the cleaning blade 71 from the photosensitive drum 40 and contains the waste toner.

The coil auger 73 is rotated around the rotational axis L for transporting the waste toner contained in the housing 72 in the axial direction D. The coil auger 73 can be elongated and contracted in the axial direction D. The coil auger 73 is made of metal. The coil auger 73 extends in the axial direction D within the housing 72, and extends from the housing 72 in the axial direction D. For example, one end 73a of the coil auger 73 in the axial direction D is extended to the outside of the housing 72. Further, upon elongation the outer diameter of the coil auger 73 is smaller than the inner diameter of the housing 72. In some examples, the coil auger 73 comprises a shaftless screw having the shape of a screw, and helically formed of a wire member.

The gear unit 74 includes an input gear 74a that rotates around the same axis as the rotational axis of the photosensitive drum 40, an idler gear 74b engaging the input gear 74a, and a screw gear 74c engaging the idler gear 74b for rotating the coil auger 73. The input gear 74a receives a rotary driving force from a motor and is rotated thereby and, in response to this rotation, the photosensitive drum 40 and the idler gear 74b are rotated.

The idler gear 74b is rotated in a direction opposite to the input gear 74a, and the screw gear 74c is rotated in response to the rotation of the idler gear 74b. The screw gear 74c is rotated in a direction opposite to the idler gear 74b, and is rotated around the rotational axis L of the coil auger 73. The idler gear 74b or the screw gear 74c of the gear unit may include a helical gear which generates a thrust force in a direction to pull the coil auger 73. In this case, the coil auger 73 can be elongated during rotation of the gear unit.

The duct 75 projects from the housing 72 in the axial direction D. The coil auger 73 passes through the inside of the duct 75, for containing the waste toner transported from the housing 72 by the coil auger 73. The duct 75 includes a first tubular portion 75a extending from the housing 72, a flange portion 75b enlarged from the first tubular portion 75a, and a second tubular portion 75c positioned on a side of the flange portion 75b opposite to the first tubular portion 75a. The second tubular portion 75c has a discharge port 75d for discharging the waste toner from within the duct 75. In some examples, the discharge port 75d may be rectangular. On the side closer to the flange portion 75b than the discharge port 75d, a shutter opening and closing spring 80 (elastic body), described later in further detail, is wound around the outer circumference of the second tubular portion 75c.

The waste toner transport device 70 is further provided with a waste toner collection container 76 (second housing) having an inlet port 76a for receiving the waste toner transported by the coil auger 73, and a screw holder 77 (screw support member) for supporting one end of the coil auger 73. Additionally, the waste tone transport device 70 may include a tension cam 78 (screw support member) for moving the screw holder 77 in the axial direction D, a rotary shutter 79 (open and close member) for opening and closing the discharge port 75d, and the aforementioned shutter opening and closing spring 80.

As illustrated in FIG. 3 and FIG. 4, the waste toner collection container 76 may be formed in the shape of a box, and receives the waste toner transported by the coil auger 73 through the inlet 76a. The waste toner collection container 76 has a projection 76b projecting toward the housing 72, and a recess 76c depressed in the axial direction D at the inlet port 76a. A projected end 76d of the projection 76b and a bottom surface 76e of the recess 76c are angled with respect to the axial direction D. The bottom surface 76e is curved in an extended arch.

The screw holder 77 is supported movably in the axial direction D and rotatably fixed with respect to the waste toner collection container 76. The screw holder 77 is disposed inside the waste toner collection container 76 and supports the one end 73a of the coil auger 73 in the axial direction D. The screw holder 77 has a plate portion 77a extending along a plane orthogonal to the axial direction D, and a protrusion 77b projecting from the plate portion 77a toward the housing 72. The one end 73a of the coil auger 73 is wound around and fixed to the protrusion 77b.

As illustrated in FIG. 4, FIG 5(a) and FIG. 5(b), the tension cam 78 is of a cylindrical shape and contains the screw holder 77 therein. The screw holder 77 is fitted into the tension cam 78. The tension cam 78 is movable in the axial direction D along with the screw holder 77 and is rotatably fixed with respect to the waste toner collection container 76. The tension cam 78 includes a sloping surface 78c to which the shutter 79 abuts from the side of the housing 72.

The shutter 79 covers an end of the duct 75 in the axial direction D and is rotatably mounted to the duct 75 but unmovable along the axial direction D. The shutter 79 includes a tube portion 79a through which the coil auger 73 and the duct 75 are passed, a first fit portion 79b for fitting with the waste toner collection container 76, and a second fit portion 79c for fitting with the tension cam 78. The tube portion 79a is formed in a cylindrical shape and has an opening 79e (see FIG. 2 and FIG. 3) to communicate with the discharge port 75d upon rotation. The opening 79e is, for example, in a rectangular shape.

The first fit portion 79b is formed on the side of the housing 72 of the tube portion 79a, and the second fit portion 79c is formed on the side of the tension cam 78 of the tube portion 79a. The first fit portion 79b fits with the recess 76c of the waste toner collection container 76, and the waste toner collection container 76 is attached to the shutter 79 by the first fit portion 79b. The first fit portion 79b has a sloping surface 79d for making surface contact with the bottom surface 76e of the recess 76c. The second fit portion 79c has a sloping surface 79f for making surface contact with the sloping surface 78c of the tension cam 78 and sloped with respect to the axial direction D.

The shutter 79 may include a rotary type shutter which is rotated to open and close the discharge port 75d of the waste toner to the waste toner collection container 76. FIG. 4, FIG 5(a) and FIG. 5(b) illustrate states in which the discharge port 75d is closed off by the shutter 79, and FIG. 6, FIG. 7(a) and FIG. 7(b) illustrate states in which the shutter 79 opens the discharge port 75d. As illustrated in FIG. 4, FIG 5(a) and FIG. 5(b), the shutter 79 closes off the discharge port 75d when the waste toner collection container 76 is separated from the shutter 79. In some examples, the position of the opening 79e and the position of the discharge port 75d in the rotational direction are displaced from each other. At that time, the tube portion 79a of the shutter 79 covers the discharge port 75d and the sloping surface 79f of the second fit portion 79c makes surface contact with the sloping surface 78c of the tension cam 78.

The shutter opening and closing spring 80 is wound around the outer circumference of the second tubular portion 75c of the duct 75, as described above. The shutter opening and closing spring 80 may include, for example, a torsional spring that urges the shutter 79 in a rotational direction. The shutter opening and closing spring 80 urges the shutter 79 in a direction to close off the discharge port 75d.

The waste toner transport device 70 is provided with a screw elongation apparatus 90 for switching between an elongated state, in which the coil auger 73 is elongated, and an elongation released state in which the elongation of the coil auger 73 is released. The screw elongation apparatus 90 includes the aforementioned waste toner collection container 76, the screw holder 77, the tension cam 78 and the shutter 79.

The elongated state of the coil auger 73 attained by the screw elongation apparatus 90 is now described in further detail. As illustrated in FIG. 4, FIG. 5(a) and FIG. 5(b), the coil auger 73 is in the elongation released state when the waste toner collection container 76 is separated from the shutter 79. Then, when attaching the waste toner collection container 76 to the shutter 79, the projection 76b of the waste toner collection container 76 abuts against the first fit portion 79b of the shutter 79. In response to the abutment, the sloping surface 79d of the first fit portion 79b is moved relative to the projected end 76d of the projection 76b, and the shutter 79 is thereby rotated relative to the duct 75.

As illustrated in FIG. 6, FIG. 7(a) and FIG. 7(b), as the shutter 79 is rotated, the first fit portion 79b fits with the recess 76c, and the opening 79e is made to communicate with the discharge port 75d so that the shutter 79 opens the discharge port 75d. Accordingly, the attachment of the waste toner collection container 76 and the opening of the discharge port 75d are made in a coordinated manner.

Further, as the shutter 79 is rotated, the sloping surface 79f of the second fit portion 79c rotates relative to the sloping surface 78c of the tension cam 78, so that the shutter 79 pushes out the tension cam 78 in the axial direction D (to the right on the sheet of FIG. 6, FIG. 7(a) and FIG. 7(b)). When the tension cam 78 is pushed out in the axial direction D, the screw holder 77 is pushed out in the axial direction D together with the tension cam 78, and the coil auger 73 is elongated in the axial direction D by the pushing out of the screw holder 77.

As described above, when the shutter 79 is rotated relative to the duct 75 and the tension cam 78, and the tension cam 78 and the screw holder 77 are pushed out in the axial direction D, the screw elongation apparatus 90 elongates the auger 73 and transitions to the elongated state. At that time, the gear unit 74 is rotated so that the gear unit 74 elongates the coil auger 73 in a direction opposite to the direction of elongation of the screw elongation apparatus 90.

On the other hand, when removing the waste toner collection container 76 from the shutter 79 for replacement or the like of the waste toner collection container 76, the shutter 79 is rotated by the urging force of the shutter opening and closing spring 80 in the direction of elongation of the screw elongation apparatus 90, thereby closing off the discharge port 75d and pulling the tension cam 78 and the screw holder 77 back to the side of the shutter 79. In response to the pulling, the screw elongation apparatus 90 releases the elongation of the coil auger 73, and transitions to the elongation released state. At that time, as the elongation of the coil auger 73 is released and the coil auger 73 contracts, the waste toner in the housing 72 and the duct 75 can be stirred.

Next, an example operation of the waste toner transport device 70 and the image forming apparatus 1 will be explained in further detail. The image forming apparatus 1 and the waste toner transport device 70 comprise the housing 72 for collecting the waste toner, and the screw-shaped coil auger 73 is disposed in the housing 72. The coil auger 73 can be elongated by the screw elongation apparatus 90 provided at one end in the axial direction D of the coil auger 73. As such, when the coil auger 73 is elongated by the screw elongation apparatus 90, slackening of the coil auger 73 can be suppressed and the posture of the coil auger 73 can be stabilized.

Accordingly, the suppression of slackening of the coil auger 73 can suppress contact of the coil auger 73 with inner wall surfaces of the associated components, and the generation of noise caused by contact of the coil auger 73 can thus be suppressed. Further, maintaining the coil auger 73 in the tensioned state for a prolonged period of time may result in deformation or failure due to creep that occurs in components supporting the coil auger 73. However, the screw elongation device 90 is switched between the elongated state, in which the coil auger 73 is elongated, and the elongation released state in which the elongation of the coil auger 73 is released, such that deformation or failure of the components due to creep can be suppressed.

Further, the coil auger 73 can be elongated and contracted in the axial direction D, and the outer diameter of the elongated coil auger 73 is smaller than the inner diameter of the housing 72. In other words, the outer diameter of the coil auger 73 elongated in the axial direction D is smaller than the inner diameter of the housing 72. As a result, contact of the elongated coil auger 73 with the inner wall surface of the housing 72 can be suppressed, and the occurrence of noise in the elongated state can be suppressed.

Further, the screw elongation device 90 includes the waste toner collection container 76 for receiving the waste toner stirred and transported by the coil auger 73, and the shutter 79 for opening and closing the waste toner discharge port 75d to the waste toner collection container 76. The screw elongation device 90 elongates the coil auger 73 when the discharge port 75d is opened by the shutter 79, and releases (relaxes) the elongation of the coil auger 73 when the discharge port 75d is closed off by the shutter 79. As a result, the resulting elongation and contraction of the coil auger 73 by the screw elongation device 90 and the opening or closing of the discharge port 75d can be coordinated.

Further, the coil auger 73 can be elongated under a state where the discharge port 75d is opened and the waste toner transport device 70 is operated to allow for receiving the waste toner. Also, the elongation of the coil auger 73 can be released (relaxed) under a state where the waste toner transport device 70 is rested and the discharge port 75d is closed off. Consequently, the coil auger 73 can be elongated when the waste toner can be discharged through the discharge port 75d and can be allowed to contract or return to a non-elongated state when the discharge is not available. Accordingly, switching between the elongated state and the elongation released (relaxed) state can be performed.

Further, the screw elongation device 90 includes the screw holder 77 and the tension cam 78 that support one end in the axial direction D of the coil auger 73. The shutter 79 is rotated around the axis of the coil auger 73 for opening and closing the discharge port 75d. When the shutter 79 is rotated to open the discharge port 75d, the screw elongation device 90 pushes out the tension cam 78 in the axial direction D for elongating the coil auger 73. In this manner, the rotary shutter 79 can be used as the screw elongation device 90.

Further, the screw elongation device 90 elongates the coil auger 73 by pushing out the tension cam 78 when the discharge port 75d is opened by the rotation of the shutter 79. Accordingly, the rotary operation of the shutter 79 and the elongation and contraction of the coil auger 73 can be coordinated. Consequently, when the rotary shutter 79 is used, the coil auger 73 can be switched between the elongated state and the elongation released (e.g., contracted) state.

Further, the waste toner transport device 70 is provided with the shutter opening and closing spring 80 for urging the shutter 79 in a direction to close off the discharge port 75d. In some examples, the shutter opening and closing spring 80 is provided between the shutter 79 and the duct 75 extending from the housing 72 and formed with the discharge port 75d. The shutter opening and closing spring 80 urges the shutter 79 in the direction to close off the discharge port 75d. As a result, the elongation of the coil auger 73 is released as the shutter 79 performs closing, and a transition to the elongation released state can be made without relying on the elongation of the coil auger 73. As such, the transition to the elongation released state can be made due to urging by the shutter opening and closing spring 80, and deformation or failure of the components due to creep can be suppressed.

Further, the gear unit 74 for rotating the coil auger 73 is provided at an end of the coil auger 73 opposite to the screw elongation device 90. Upon rotation, the gear unit 74 elongates the coil auger 73 in a direction opposite to the direction of elongation of the screw elongation device 90. Therefore, as the coil auger 73 is pulled in a direction opposite to the screw elongation device during rotation of the gear unit 74, the amount of tensioning of the coil auger 73 can be made larger. Consequently, slackening of the coil auger 73 and contact of the coil auger 73 with the inner wall surfaces can be suppressed.

Further, the gear unit 74 elongates the coil auger 73 during rotation in the aforementioned elongated state. Accordingly, as the gear unit 74 is rotated to pull the coil auger 73 while the coil auger 73 is being elongated by the screw elongation device 90, slackening of the coil auger 73 can be suppressed further during the rotation of the gear unit 74.

It is to be understood that not all aspects, advantages and features described herein may necessarily be achieved by, or included in, any one particular example. Indeed, having described and illustrated various examples herein, it should be apparent that other examples may be modified in arrangement and detail is omitted.

For example, while the gear unit 74 may be provided with the input gear 74a, the idler gear 74b and the screw gear 74c, in other examples the construction of the gear unit for rotationally driving the coil auger 73 may be changed with respect to the number, shape, size, material and arrangement of the gears in the gear unit.

Further, while the duct 75 may include the first tubular portion 75a, the flange portion 75b, and the second tubular portion 75c and the waste toner collection container 76 having the projection 76b and the recess 76c, in other examples the shape, size, material and arrangement of the duct and the waste toner collection container may also be changed.

Further, while the screw elongation device 90 may be provided with the waste toner collection container 76, the screw holder 77, the tension cam 78 and the shutter 79, the construction of the screw elongation device may be changed. Further, the shape, size, material and arrangement of the screw holder, the tension cam and the shutter may also be changed. Furthermore, an integral screw support member may be provided in place of the screw holder 77 and the tension cam 78, and a non-rotary type shutter may be provided in place of the shutter 79. Also, the shape, size, number, material and arrangement of the shutter opening and closing spring may be changed.

Further, although the elongation and contraction of the coil auger 73 may be performed by the screw elongation device 90 coordinated with the opening and closing of the discharge port 75d, in other examples the elongation and contraction of the coil auger 73 may not be coordinated with the opening and closing of the discharge port 75d. Rather, in some examples the elongation and contraction of the coil auger 73 may be coordinated with other operations associated with the waste toner transport device or the image forming apparatus. Further, the elongation and contraction of the coil auger 73 may not be coordinated with other operations and may be performed individually.

Further, although the waste toner transport member may include the coil auger 73 made of a metal wire, other examples include a different shape, size, material, number and arrangement of the waste toner transport member. For example, a waste toner transport member in which metal plates are helically arranged may be provided in place of the coil auger 73.

Claims

A waste toner transport device comprising:

a housing to collect a waste toner;

a screw-shaped waste toner transport member disposed in the housing, the waste toner transport member to stir and transport the waste toner; and

a screw elongation apparatus located at one axial end of the waste toner transport member, the screw elongation apparatus to elongate the waste toner transport member in an axial direction,

wherein the screw elongation apparatus is switched between an elongated state, in which the waste toner transport member is elongated, and an elongation released state in which the elongation of the waste toner transport member is relaxed.
The waste toner transport device according to claim 1, the waste toner transport member to switch between being elongated and contracted in the axial direction, and

wherein an outer diameter of the waste toner transport member in the elongated state is smaller than an inner diameter of the housing.
The waste toner transport device according to claim 1,

wherein the screw elongation apparatus includes a second housing to receive the waste toner stirred and transported by the waste toner transport member, and an open and close member to open and close a waste toner discharge port to the second housing,

the screw elongation apparatus to elongate the waste toner transport member when the discharge port is opened by the open and close member, and to relax the elongation of the waste toner transport member when the discharge port is closed off by the open and close member.
The waste toner transport device according to claim 3,

wherein the screw elongation apparatus includes a screw support member which supports one end in the axial direction of the waste toner transport member and is movable in the axial direction,

the open and close member to rotate around the axis of the waste toner transport member for opening and closing the discharge port, and

when the open and close member is rotated to open the discharge port, the screw elongation apparatus to push out the screw support member in the axial direction for elongating the waste toner transport member.
The waste toner transport device according to claim 3, further comprising an elastic body to urge the open and close member in a direction to close off the discharge port, the elastic body provided between the open and close member and a duct extending from the housing.
The waste toner transport device according to claim 1, further comprising gearing to rotate the waste toner transport member, the gearing provided at an end of the waste toner transport member opposite to the screw elongation apparatus, and

upon rotation, the gearing to elongate the waste toner transport member in a direction opposite to the direction of elongation of the screw elongation apparatus.
The waste toner transport device according to claim 6, the gearing to elongate the waste toner transport member during rotation in the elongated state.
An image forming apparatus comprising the waste toner transport device according to claim 1.
A waste toner transport device, comprising:

a housing to collect a waste toner;

a waste toner transport member disposed in the housing, the waste toner transport member to transport the waste toner; and

an elongation apparatus located at one axial end of the waste toner transport member, the elongation apparatus to elongate the waste toner transport member in an axial direction,

wherein the elongation apparatus is switched between an elongated state, in which the waste toner transport member is elongated, and a contracted state in which the elongation of the waste toner transport member is relaxed.
The waste toner transport device according to claim 9, wherein the waste tone transport member comprises a screw-shaped waste toner transport member.
The waste toner transport device according to claim 10, the screw-shaped waste toner transport member to both stir and transport the waste toner.
The waste toner transport device according to claim 9, wherein the elongation apparatus comprises a screw elongation apparatus.
The waste toner transport device according to claim 9, wherein an outer diameter of the waste toner transport member in the elongated state is smaller than an inner diameter of the housing.
The waste toner transport device according to claim 9, wherein the screw elongation apparatus includes a second housing to receive the waste toner transported by the waste toner transport member, and an open and close member to open and close a waste toner discharge port to the second housing.
The waste toner transport device according to claim 14, the screw elongation apparatus to elongate the waste toner transport member when the discharge port is opened by the open and close member, and to relax the elongation of the waste toner transport member when the discharge port is closed off by the open and close member.