JP2021081511A - Toner conveying device and image forming apparatus - Google Patents

Abstract

To provide a technology that can improve toner conveyance efficiency on a toner conveyance path that is affected by the gravity largely on a downstream side compared with an upstream side.SOLUTION: A toner conveying device 14 is used for an image forming apparatus. A downstream side screw 114 is configured such that a downstream end of a rotation shaft 114A is located at a position higher than an upstream end of the rotation shaft 114A in a toner conveyance direction of the screw, and the angle of the rotation shaft 114A with respect to a horizontal plane becomes larger than that of a rotation shaft 105A. A backflow prevention rib 106 is provided which projects toward the axis of rotation 105c of the rotation shaft 105A from an area of a first conveyance path forming part located between a downstream end of a blade part 105B on the most downstream in the toner conveyance direction of an upstream side screw 105 and a connection part of the first conveyance path forming part connected to a second conveyance path forming part and located above the rotation shaft 105A. The backflow prevention rib 106 overlaps the blade part 105B when viewed in the direction of the axis of rotation 105c of the rotation shaft 105A.SELECTED DRAWING: Figure 2

Description

The present invention relates to a toner transfer device for transporting toner and an electrophotographic image forming device including the toner transfer device.

Conventionally, in an image forming apparatus such as a printer, a copier, or a facsimile using an electrophotographic method, a toner accommodating portion for initially storing toner, a toner conveying means for conveying toner, and an image arranged downstream thereof. There is an apparatus configuration composed of three forming portions.
As a toner transfer configuration, a screw having a rotation shaft at the center and spirally extending blades on the outer periphery thereof is arranged and rotated in the transfer path to transfer toner from the upstream to the downstream of the transfer path. There is a configuration to do.
Patent Document 1 describes a configuration in which toner is dropped and transported from a toner bottle arranged on the upper side in the vertical direction from a toner supply port to a developing device via a toner transport path. At this time, as shown in FIGS. 9 and 10 in Patent Document 1, the toner transfer path is composed of a plurality of screws, is connected to each other, changes the transfer direction and height, and supplies desired toner. Transport the toner to the mouth.
For example, in the configuration shown in FIG. 10 in Patent Document 1, two screws are crossed and toner is delivered from upstream to downstream. In the delivery portion, the downstream end of the upstream screw and the upstream end of the downstream screw are arranged so as to intersect each other so as to overlap in the vertical direction. When the toner transported by the upstream screw reaches the downstream end of the upstream screw, it is guided to the downstream screw with the assistance of gravity, and is eventually transported further downstream by the downstream screw. Toner.
Further, Patent Document 2 also discloses a configuration in which two screws are crossed, toner is delivered from an upstream screw to a downstream screw, and toner is conveyed.
As shown in FIG. 5 in Patent Document 2, the upstream screw and the downstream screw intersect each other, and the toner is transported downstream in the transport direction.

Japanese Unexamined Patent Publication No. 2014-157350 Japanese Patent Application Laid-Open No. 2012-230358

In these conventional techniques, gravity applied to the toner is applied in addition to the conveying force of the screw acting on the toner at the transfer portion from the upstream screw to the downstream screw. By the sum of these forces, the toner is pushed out from the path where the upstream screw is arranged and flows into the path where the downstream screw is arranged.
As in the arrangement shown in FIG. 9 in Patent Document 1, even if a space is formed above the horizontally arranged screw when viewed from the axial cross section, the toner does not enter the space and the screw does not enter. Is transported in the axial direction of.
This indicates that the carrying force exerted by the screw on the toner cannot push the toner upward against the gravity. This indicates that the radial carrying force generated by the screw is smaller than the gravity acting on the toner. That is, it can be said that the conveying force acting on the toner when the toner is transferred from the upstream to the downstream screw is the total value, and at least half of it is generated by gravity.
Therefore, under the following conditions where gravity acts as a resistance to toner transfer, there are cases where sufficient toner transfer force cannot be obtained.
(1) When the screw on the downstream side is arranged on the upper side in the vertical direction with respect to the screw on the upstream side As described above, in order to transport toner against gravity, only the radial transport force of the screw is required. Due to the shortage, the toner may not be transferred smoothly.
(2) When the arrangement angle of the downstream screw is inclined so as to increase as it becomes downstream. In particular, in the case of the arrangement configuration in which the downstream screw extends in the vertical direction, the radial direction generated by the downstream screw. It is necessary for the upstream screw to push the toner from the upstream transport path into the downstream transport path through the communication port, overcoming the toner transport force of the above. Therefore, there are cases where the conventional type upstream screw, which does not have a sufficient carrying force, cannot resist the backflow force of the downstream screw.
In the conventional technology, when such a configuration is adopted, the transfer portion between the upstream screw and the downstream screw becomes a bottleneck and the transfer efficiency is lowered, and the system with respect to the maximum transfer force of each screw. The total maximum carrying capacity is reduced.
Conventionally, as an image forming apparatus, the amount of toner required by the process cartridge is set, and in order to satisfy this, the rotation speed of the screw has been increased to satisfy the conveyed amount.
However, while the required transport amount is achieved, the operating noise increases due to the increase in the number of revolutions. In addition, the cumulative number of rotations of the screws in the toner transfer device increases within the product life of the image forming apparatus, so that the device life is shortened.
Further, as a means of increasing the conveying force without increasing the screw rotation speed, it is conceivable to increase the cross-sectional area of the screw, but the volume of the device increases, which affects the size of the entire image forming device.

An object of the present invention is to provide a technique capable of improving the toner transfer efficiency in a toner transfer path in which the downstream side is more affected by gravity than the upstream side.

In order to achieve the above object, the toner transfer device of the present invention
A toner transfer device used in an image forming device.
A first transport unit having a first screw having a first rotation shaft and a first blade portion and a first transport path forming portion that surrounds the first screw so as to form a space between the first screw. When,
The second screw having the second rotation shaft and the second blade portion and the second transport path forming portion that surrounds the second screw so as to form a space between the second screw and the second screw. A second transport unit for transporting toner transported by one transport unit, and
With
In the toner transport direction of the second screw, the downstream end of the second rotation shaft of the second screw is higher than the upstream end of the second rotation shaft, and the angle of the second rotation shaft with respect to the horizontal plane is large. It is configured to be larger than that of the first rotation axis.
The said, which is between the downstream end of the first blade portion which is the most downstream in the toner transport direction of the first screw and the connection portion connected to the second transport path forming portion of the first transport path forming portion. A protruding portion is provided that protrudes from the region of the first transport path forming portion above the first rotating shaft toward the rotating axis of the first rotating shaft.
The protruding portion is characterized in that it overlaps with the first blade portion when viewed in the direction of the rotation axis of the first rotation axis.
In order to achieve the above object, the image forming apparatus of the present invention
An image forming part that forms an image on a recording material using toner,
A storage unit that stores toner and
A toner transporting unit that transports toner from the accommodating portion to the image forming unit,
In an image forming apparatus including
The toner transporting unit is the toner transporting device of the present invention.

According to the present invention, it is possible to improve the toner transfer efficiency in the toner transfer path in which the downstream side is more affected by gravity than the upstream side.

Inclined view of the toner transfer device according to the first embodiment of the present invention. Configuration explanatory view of the toner transfer apparatus according to the first embodiment of the present invention. Schematic cross-sectional view of the image forming apparatus according to the embodiment of the present invention. Schematic cross-sectional view of the toner transfer device according to the second embodiment of the present invention. Schematic diagram showing a configuration example of a backflow prevention rib (protruding portion) in an embodiment of the present invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail exemplarily based on examples with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments.

[Example 1]
The image forming apparatus 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view showing the overall configuration of the image forming apparatus 1, and is a cross-sectional view of the image forming apparatus 1 when viewed from the front side. FIG. 3 shows the configuration of the image forming apparatus in a normal installation state in which the image forming apparatus is placed on a horizontal installation surface, and the horizontal direction of the paper surface corresponds to the horizontal direction and the vertical direction of the paper surface corresponds to the vertical direction of the device. .. In the following description with reference to other than FIG. 3, the content of the explanation regarding the directions such as up, down, left, and right is based on FIG.

The image forming apparatus 1 horizontally sets the image forming stations 6Y, 6M, 6C, and 6K corresponding to the toners (developer) for each color of yellow (Y), magenta (M), cyan (C), and black (K). An image forming unit 6 is provided as an image forming means arranged side by side in a row. The image forming unit 6 includes the photoconductor drums 7Y, 7M, 7C, 7K (hereinafter unified as the photoconductor drum 7), which are image carriers, and charging devices 8Y, 8M, 8C that uniformly charge the surface of the photoconductor drum 7. , 8K (charging device 8) is installed internally. Further, developing devices 9Y, 9M, 9C, 9K (developing device 9) that adhere toner to the electrostatic latent image and develop it as a toner image (developer image) are installed internally. Further, a photoconductor cleaning blade 10Y, 10M, 10C, and 10K (photoreceptor cleaning blade 10) for removing residual toner remaining on the photoconductor drum 7 are provided internally. The developing apparatus 9 is provided with developing rollers 11Y, 11M, 11C, and 11K (developing rollers 11) corresponding to each color so as to be in contact with and separated from each photoconductor drum 7. The life of the developing roller 11 is improved by bringing the developing rollers 11 into contact with each other and separating them according to the electrostatically imaged image, that is, depending on whether or not development is necessary. A scanner unit 12 that irradiates a laser beam based on the image information to form an electrostatic latent image on the photoconductor drum 7 is provided at the lower part of the image forming unit 6. The image forming stations 6Y, 6M, 6C, and 6K are configured as process cartridges to be detachably attached to the main body of the image forming apparatus 1. The process cartridge includes a developing device 9 provided with a developing roller 11 and a photoconductor unit provided with a photoconductor drum 7, a charging device 8, and a cleaning blade 10, individually or integrally with the device body. It is configured to be removable. In this embodiment, the developing device 9 has its own toner storage chamber, but the toner supplied from the replenishment toner container (toner cartridge) 13 described later is replenished in the toner storage chamber. Here, the apparatus main body of the image forming apparatus 1 refers to a constituent portion excluding a configuration that is detachable from the image forming apparatus 1 such as the process cartridge described above and the replenishing toner container 13 described later.

On the other hand, the cassette 2 is retractably housed in the lower part of the image forming apparatus 1. A recording material 4 such as paper or a sheet is stored in the cassette 2. As the cassette paper feed unit 3 arranged near the tip of the recording material 4 rotates, the recording material 4 is separately fed one by one. After that, it is conveyed downstream by the resist roller 5.

An intermediate transfer unit 16 is provided above the developing device 9. The intermediate transfer unit 16 is arranged substantially horizontally with the side (primary transfer unit 20 side) facing each image forming station (image forming unit) 6 facing downward. The intermediate transfer belt 18 facing each photoconductor drum 7 is a rotatable endless belt, and is stretched on a plurality of tension rollers. Primary transfer rollers 19Y, 19M, 19C, 19K (primary transfer roller 19) are arranged as primary transfer members on the inner surface side of the intermediate transfer belt 18. Each primary transfer roller 19 is arranged at a position where each photoconductor drum 7 and the primary transfer portions 20Y, 20M, 20C, and 20K (primary transfer portion 20) are formed via the intermediate transfer belt 18. In each primary transfer unit 20, the toner image is transferred from each photoconductor drum 7 to the intermediate transfer belt 18 by the primary transfer roller 19 to which a voltage is applied. In this embodiment, a unit including an intermediate transfer belt 18, a plurality of tension rollers for tensioning the intermediate transfer belt 18, and each primary transfer roller 19 is provided as an intermediate transfer unit 16 so as to be detachable from the apparatus main body.
The toner image developed at each image forming station is transferred to the intermediate transfer belt 18 by the primary transfer unit 20, and by continuously transferring each color, a toner consisting of four colors is transferred to the surface of the intermediate transfer belt 18. An image is formed and conveyed to the secondary transfer unit 17.

A replenishment toner container (toner replenishment cartridge) 13Y, 13M for replenishing toner to each image forming station (image forming unit) 6 between the scanner unit 12 and the cassette 2 in the lower part of the image forming unit 6. , 13C, 13K (replenishment toner container 13) are arranged substantially horizontally and detachably. The inside of the replenishment toner container 13 is filled with replenishment toner corresponding to each color. The toner transfer devices 14Y, 14M, 14C, and 14K (toner transfer device 14) transfer the toner received from the replenishment toner container 13 upward in accordance with the toner consumption in the image forming unit 6, and transfer the toner to the developing device 9. Supply. The toner transfer device 14 is driven by the toner transfer drive devices 15Y, 15M, 15C, and 15K (toner transfer drive device 15) as drive means arranged below the toner transfer device 14. The toner transfer drive device 15 is a power source for providing a driving force for rotationally driving each screw of the toner transfer device 14 to the toner transfer device 14 via an upstream drive gear 103, a downstream drive gear 112, etc., which will be described later. It is equipped with a motor and a gear as a drive transmission means.

The secondary transfer roller 21, which is a secondary transfer member, comes into contact with the intermediate transfer belt 18 and forms a secondary transfer portion 17 with a roller on the opposite side via the intermediate transfer belt 18. The toner image transferred on the intermediate transfer belt 18 by the secondary transfer unit 17 is secondarily transferred to the recording material 4. The toner that cannot be completely transferred to the recording material 4 by the secondary transfer and remains on the intermediate transfer belt 18 is removed by the cleaning unit 22. The toner removed by the cleaning unit 22 is transported to the toner collection container 24 via the toner transport unit 23 and accumulated.

The recording material 4 to which the unfixed toner image is transferred in the secondary transfer unit 17 is conveyed further downstream, and is pressurized and heated by the heating unit 25a and the pressure roller 25b of the fixing device 25 to melt the toner. The toner image is fixed on the recording material 4. After that, the recording material 4 is conveyed by the discharge roller pair 26 and discharged to the paper discharge tray 27. By these series of operations, an image is formed on the surface of the recording material 4.

(Toner transfer device)
FIG. 1 is a schematic perspective view showing an outline configuration of a toner transfer device 14 mounted on the image forming apparatus of this embodiment. In FIG. 1, a part of the shape is removed to show the internal configuration of the toner transfer device 14.

The toner transfer device 14 is roughly divided into an upstream side transfer unit 100 and a downstream side transfer unit 110.

A supply port 101 is arranged on the upper surface of the upstream side transport unit 100, and the toner supplied from the replenishment toner container 13 shown in FIG. 3 passes through the supply port 101 and is on the upstream side inside the upstream side transport unit 100. It is supplied into the first toner transfer path formed by the wall surface 104. The supplied toner is conveyed by rotating the upstream screw 105 as the first screw arranged so as to be covered by the upstream side wall surface 104 inside the upstream conveying portion 100. The upstream screw 105 is rotationally driven by transmitting a rotational driving force from the toner transfer driving device 15 to the upstream drive gear 103, and the upstream screw 105 transfers toner in the direction of the downstream transfer unit 110. It has become.

The upstream side transport unit 100 forms a first transport path forming portion that forms the first toner transport path 108 on the upstream side and a second transport path forming portion that forms a part of the upstream side of the second toner transport path 109 on the downstream side. The unit has a communication port 107 that communicates the first toner transfer path 108 and the second toner transfer path 109.
The upstream screw 105 has a rotation shaft 105A as a first rotation shaft, and a blade portion 105B formed so as to spirally wind around the outer circumference of the rotation shaft 105A.
The upstream screw 105 can be rotated in a substantially horizontal arrangement in the first toner transport path 108 formed by the first transport path forming portion among the transport paths formed by the upstream transport portion 100. It is provided. In the upstream screw 105, the end of the rotary shaft 105A on the side that is driven and connected to the upstream drive gear 103 (the upstream end of the upstream transport portion 100 in the toner transport direction) is attached to the casing of the upstream transport portion 100. It is rotatably supported.
The communication port 107 is provided so as to be connected to the first toner transfer path 108 along the axial direction of the rotation shaft 105A of the upstream screw 105.
A part of the upstream side of the second toner transfer path 109 formed by the second transfer path forming portion in the upstream transfer portion 100 is an upstream end at the tip (downstream side) of the communication port 107 along the axial direction of the rotating shaft 105A. There is, and it extends upward (in the direction against gravity) from there.
That is, the transport path formed by the upstream transport section 100 is formed in a substantially L shape including the first toner transport path 108, the communication port 107, and a part of the upstream side of the second toner transport path 109. Will be done.

The downstream transport section 110 has a second transport path forming section that forms a second toner transport path 109 that extends substantially vertically (in a direction against gravity) downstream of the first toner transport path 108. The second transport path forming portion included in the downstream transport section 110 is a second transport path forming section excluding a part 109a on the upstream side of the second toner transport path 109 formed by the second transport path forming section of the upstream transport section 100. Most of the toner transport path 109 is formed 109b. That is, in the second toner transport path 109, a part 109a on the upstream side is formed by the upstream transport portion 100, and a portion 109b on the downstream side is formed by the downstream transport portion 110. That is, the second transport path forming portion forming the second toner transport path 109 is provided so as to straddle the upstream side transport section 100 and the downstream side transport section 110.
The second transport path forming portion of the upstream transport section 100 has an opening for opening the second toner transport path 109 upward, and the lower end (upstream side) of the second transport path forming portion of the downstream transport section 110. The end) is inserted into the opening from above and connected. By such connection, the second toner transport path 109a of the upstream transport section 100 and the second toner transport path 109b of the downstream transport section 110 communicate with each other to form one second toner transport path 109.
The first toner transfer path 108 is a space formed between the upstream side wall surface 104 of the upstream side transfer portion 100 and the upstream side screw 105.
The second toner transport path 109 is a space formed between the downstream side wall 113 connected between the upstream transport portion 100 and the downstream transport portion 110 and the downstream screw 114.

The downstream screw 114 as the second screw is rotatably provided in the second toner transport path 109 in a vertically extending arrangement, and is provided inside the downstream transport portion 110 (109b) and on the upstream transport portion 100. It is housed across the interior (109a).
The downstream screw 114 is arranged inside the downstream transport portion 110 so as to be covered with the downstream side wall surface 113 thereof. The most upstream portion of the downstream transport unit 110 is connected to the most downstream portion of the upstream transport unit 100, and the toner conveyed by the upstream screw 105 of the upstream transport unit 100 passes through the communication port 107. After that, it is conveyed by the downstream screw 114. The downstream screw 114 is rotationally driven by transmitting a rotational driving force from the toner transfer driving device 15 to the downstream drive gear 112, and the downstream screw 114 transfers toner in the direction opposite to gravity. In the downstream screw 114, the end portion of the rotating shaft 114A on the side driven and connected to the downstream driving gear 112 (the upstream end portion in the toner transport direction in the downstream transport portion 110) rotates in the casing of the downstream transport portion 110. It is possible to support the axis. The toner conveyed in the direction opposite to gravity by the downstream screw 114 is further conveyed by the discharge screw 116 as the third screw, and is discharged from the downstream transfer unit 110 via the discharge port 111. The discharge screw 116 is in contact with the upstream end of the blade portion so as to be driven and connected to the downstream end of the blade portion of the downstream screw 114, and is rotated by the driving force received from the rotating downstream screw 114. To do. The toner discharged from the discharge port 111 by the discharge screw 116 is supplied (supplied) to the developing device 9 shown in FIG.

FIG. 2 is a diagram illustrating a detailed configuration of a connection portion (communication port 107) between the first toner transfer path 108 and the second toner transfer path 109 described above, and FIG. 2A is a top view of the toner transfer device 14; b) is an AA'cross-sectional view of (a) showing only the periphery of the connection portion of the toner transfer device 14, and (c) is a BB' cross-sectional view of (a).

As shown in FIG. 2B, a degassing member 102 is arranged on the upper surface of the upstream transport portion 100. The degassing member 102 is made of a non-woven fabric, and uses a material that allows air to pass through without passing toner. Without the degassing member 102, when toner is supplied from the replenishment toner container 13 shown in FIG. 3, the air pressure in the space inside the upstream transport unit 100 increases. When this air pressure increases, a pressure difference with the replenishment toner container 13 occurs, and toner is no longer supplied from the replenishment toner container 13 to the inside of the upstream transport unit 100.

The toner supplied from the replenishment toner container 13 is first conveyed by the upstream screw 105, and then conveyed by the downstream screw 114. A gap is provided in the axial direction of the rotating shaft 105A between the downstream end 105a of the rotating shaft 105A of the upstream screw 105 and the outer diameter end 104a of the blade portion 114B of the downstream screw 114. The area provided with this gap may be regarded as the communication port 107. The length of the gap (communication length of the communication port 107) is such that the toner in the gap (inside the communication port 107) is conveyed to the second toner transfer path 109 downstream by the rotational transfer force of the upstream screw 114. The length that can be used is appropriately set according to the device specifications and the like.

In the second toner transport path 109 downstream of the gap (communication port 107), the downstream screw 114 conveys toner in the direction opposite to gravity, and at the same time, the upstream screw 105 is rotationally driven to the downstream screw 114. Toner is supplied toward. At this time, toner may flow back from the downstream screw 114 side to the upstream screw 105 side. That is, the toner that has descended from the second toner transport path 109 due to gravity may flow back to the first toner transport path 108 through the gap (communication port 107). This backflow of toner may reduce the efficiency of delivering toner from the upstream screw 105 to the downstream screw 114.
The force for transporting toner by the upstream screw 105 extending in the horizontal direction is mainly generated in a region below the rotation axis 105c of the rotation shaft 105A. Therefore, the backflow of toner mainly occurs in the region above the rotation axis 105c, and at the same time, the toner flows from the upstream screw 105 to the downstream screw 114 in the region below the rotation axis 105c. ..

Therefore, a backflow prevention rib (protruding portion) 106 is provided at the communication port 107 which is a connecting portion between the first toner transport path 108 and the second toner transport path 109. The backflow prevention rib 106 extends from the inner wall surface 113 forming the second toner transport path 109 to the rotation shaft 114A of the downstream screw 114 so as to cover the outer diameter end (outer peripheral end) 114a of the blade portion 114B of the downstream screw 114. It is formed continuously along the direction of the rotation axis of. Further, the backflow prevention rib 106 is a region (inner wall surface) of the inner wall surface 104 forming the first toner transport path 108, which covers the upper end of the outer diameter end (outer peripheral end) 105b of the blade portion 105B of the upstream screw 105 in the gravity direction. It is formed so as to protrude from the upper end of 104). That is, the backflow prevention rib 106 projects from the inner wall surface 104 toward the rotation axis 105c in a direction orthogonal to the rotation axis 105c of the rotation axis 105A. The backflow prevention rib 106 is provided so as to overlap the blade portion 105B when viewed in the direction of the rotation axis 105c of the rotation shaft 105A. Due to the backflow prevention rib 106, the width of the connection portion (communication port 107) between the first toner transfer path 108 and the second toner transfer path 109 is larger than that of the downstream end of the rotary shaft 105A in the first toner transfer path 108. It is smaller than the size of the space on the downstream side.

The amount of protrusion of the backflow prevention rib 106 from the inner wall surface 104 penetrates the rotation center axis 105c side of the outer diameter end 105b of the upstream screw 105 when viewed in the direction of the rotation axis (rotation center axis) 105c. Moreover, it is important that it is located vertically above the rotation center axis 105c. By forming the backflow prevention rib 106 within the protrusion amount range, the toner reverse flow rate from the downstream side screw 114 to the upstream side screw 105 side can be reduced without reducing the toner transfer amount from the upstream side screw 105 to the downstream side screw 114. It can be reduced.

The backflow prevention rib 106 is continuously formed by one rib, but may be intermittently formed by a plurality of ribs. Further, in the first embodiment, the tip of the backflow prevention rib 106 is a horizontal straight line along the rotation axis 105c as shown in FIG. 2C, but may be an arc or an oblique straight line.

According to this embodiment, even in a transport path configuration in which the influence of gravity is stronger on the downstream side than on the upstream side and it is difficult to transport toner, the toner transport direction is changed so that the influence of gravity is stronger. It is possible to prevent the toner transfer efficiency at the joint of the transfer path from being lowered, and to prevent disadvantages such as an increase in operating noise and a decrease in durable life. That is, according to the present embodiment, when at least two screws are connected, the toner to be conveyed can be efficiently delivered to the downstream screw by using the conveying force of the upstream screw at the transfer portion of the toner to be conveyed. .. Therefore, the number of rotations of the screw can be minimized with respect to the required toner transfer amount, so that power saving and low noise can be realized. Similarly, since the outer diameter of the screw can be minimized with respect to the required toner transfer amount, the size of the entire device can be reduced.

[Example 2]
Example 2 of the present invention will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view showing a detailed configuration of a connection portion (communication port 107) between the first toner transfer path 108 and the second toner transfer path 109 in the toner transfer device according to the second embodiment.
In the configuration of the image forming apparatus and the toner transfer apparatus according to the second embodiment, the same reference numerals are given to the configurations common to the apparatus configuration according to the first embodiment, and the description thereof will be omitted again. Matters not specifically described here in the second embodiment are the same as those in the first embodiment.

In the second embodiment, unlike the first embodiment, the backflow prevention rib 106 forms the first toner transfer path 108 independently (not continuously) from the inner wall surface 113 forming the second toner transfer path 109. The structure is formed so as to project from the wall surface 104. This assumes that the backflow prevention rib 106 cannot be formed continuously with the inner wall surface 113 due to the mold restrictions for forming the upstream transport portion 100 and the downstream transport portion 110. According to the second embodiment, the reverse flow rate of toner from the downstream screw 114 to the upstream screw 105 is reduced without reducing the amount of toner delivered from the upstream screw 105 to the downstream screw 114 regardless of the mold restriction. be able to.

[Structure example of backflow prevention rib (protruding part)]
A configuration example of the backflow prevention rib 106 will be described with reference to FIG. FIG. 5 shows the inside of forming the rotation shaft 105A of the upstream screw 105, the backflow prevention rib 106, the communication port 107, and the first toner transfer path 108 when viewed from the rotation axis 105c of the rotation shaft 105A of the upstream screw 105. It is a schematic diagram which showed the structure of the wall surface 104. FIG. 5A shows the configuration of the single backflow prevention rib 106 shown in the above embodiment, and FIG. 5B shows the configuration in which a plurality of backflow prevention ribs 106 are provided. FIG. 5C shows a configuration in which the backflow prevention rib 106 is eliminated and the backflow of toner is reduced by devising the positional relationship of the communication port 107 with the rotating shaft 105A.

The specific configuration of the backflow prevention rib 106 is not limited to the configuration of the above embodiment. That is, in the communication port 107, the flow of toner in the region above the rotation axis 105c of the rotation shaft 105A of the upstream screw 105 where toner backflow is likely to occur is hindered, but the flow of toner in the region below the rotation axis 105c is not hindered. If so, various configurations may be adopted. That is, if the area of the communication port 107 above the rotation axis 105c can be made narrower than the area below the rotation axis 105c, another configuration that does not use the backflow prevention rib 106 is used. It may be. For example, as shown in FIG. 5C, the degree of opening of the communication port 107 is shown in the embodiment by configuring the region above the rotation axis 105c to be narrower than the region below the rotation axis 105c. The same effect as the configuration using the backflow prevention rib 106 can be obtained. Although FIG. 5 shows a case where the communication port 107 is formed in a rectangular shape, it goes without saying that the shape is not limited to such a shape. It may be configured in various shapes such as a circle and a polygon. The same applies to the shape of the backflow prevention rib 106.

[Other]
The combination configuration (divided position of the upstream transport unit 100 and the downstream transport unit 110) of the members forming the first toner transport path, the communication port, and the second toner transport path is limited to the configuration of the above-described embodiment. is not it.

For example, the upstream side transport unit 100 and the downstream side transport unit 110 may be divided at the communication port 107. That is, the upstream side transport section 100 is provided with a first opening that opens at the downstream end of the first toner transport path 108, and the downstream side transport section 110 is provided with a first opening that opens at the upstream end of the second toner transport path 109. The two openings are provided so as to be continuous with the first opening along the axis of the rotation shaft 105A of the upstream screw 105. By doing so, the communication port 107 can be formed by the first opening and the second opening that are connected along the axis of the rotation shaft 105A of the upstream screw 105. Then, the toner backflow rate is reduced by providing a backflow prevention rib (protruding portion) at the edge of at least one of the first opening and the second opening and by making the width of the opening different. It can be configured as possible.

Further, the portion of the communication port 107 is regarded as a third toner transfer path having a short transfer distance, and the third transfer path forming portion forming the third toner transfer path is the first transfer path forming the first toner transfer path 108. It may be composed of a member different from the forming portion and the second transport path forming portion forming the second toner transport path 109. In this case, for example, the width of the third toner transport path formed by the third transport path forming portion is larger than the width of the opening on the downstream side of the first toner transport path 108 of the first transport path forming portion. It may be configured to be narrow in the region above the rotation axis of. Further, in this case, the third toner transport path is a toner transport path in which a transport means such as a screw is not provided. Therefore, the length of the third toner transfer path is such that the toner in the third toner transfer path is transferred to the downstream second toner transfer path 109 by the rotational transfer force of the first screw arranged in the upstream first toner transfer path 108. It is the length that can be transported to.

In the toner transport device of this embodiment, an example has been made of a configuration in which the upstream side is a transport path for transporting toner in the horizontal direction and the downstream side is a transport path for transporting toner in the vertical upward direction. Is not limited to this. That is, the present invention can be suitably applied to a transport path in which the influence of gravity on toner transport becomes stronger toward the downstream side of the transport path, similar to the transport path shown in this embodiment. For example, in the configuration of this embodiment, the first toner transport path 108 (rotational shaft 105A of the upstream screw 105) may have a slight angle (elevation angle) with respect to the horizontal plane. Further, in that case, even if the second toner transport path 109 (rotation axis 114A of the downstream screw 114) has a slight angle with respect to the vertical direction, the angle (elevation angle) from the horizontal plane is determined. If the angle is larger than the angle of the first toner transfer path 108 (rotation axis 105A of the upstream screw 105), the transfer path configuration is such that the influence of gravity becomes stronger on the downstream side. Even in such a configuration, the present invention can be suitably applied, and the same effects as those in the above examples can be obtained. Further, the change in the angle of the transport path from the horizontal plane is not limited to one change from horizontal to vertical as in this embodiment, but changes in a configuration or a curved shape that gradually changes two or more times. The present invention can be suitably applied even if it has a configuration.

The toner transport device of the present invention can be used not only for transporting new toner as in the above-described embodiment, but also for transporting waste toner such as transfer residual toner. In that case, the powder to be transported may include not only waste toner but also powder such as paper dust generated from a recording material or the like, but the main transport target is waste toner. Therefore, with the same configuration as in the above embodiment, it is possible to efficiently transport the powder to be transported as in the above embodiment.

1 ... Image forming device, 6 ... Image forming unit, 13 ... Replenishing toner container, 14 ... Toner transfer device, 100 ... Upstream transfer unit, 101 ... Supply port, 102 ... Degassing member, 103 ... Upstream drive gear, 104 ... upstream side wall surface, 105 ... upstream screw, 105A ... rotating shaft, 105B ... blade, 105a ... upstream screw downstream end, 105b ... upstream screw outer diameter, 105c ... upstream screw rotation center shaft, 106 ... backflow prevention Ribs (protruding parts), 107 ... communication port, 108 ... first toner transport path, 109 ... second toner transport path, 110 ... downstream side transport section, 111 ... discharge port, 112 ... downstream drive gear, 113 ... downstream side Wall surface, 114 ... downstream screw, 114A ... rotating shaft, 114B ... blade, 114a ... downstream screw outer diameter

Claims (12)

A toner transfer device used in an image forming device.
A first transport unit having a first screw having a first rotation shaft and a first blade portion and a first transport path forming portion that surrounds the first screw so as to form a space between the first screw. When,
The second screw having the second rotation shaft and the second blade portion and the second transport path forming portion that surrounds the second screw so as to form a space between the second screw and the second screw. A second transport unit for transporting toner transported by one transport unit, and
With
In the toner transport direction of the second screw, the downstream end of the second rotation shaft of the second screw is higher than the upstream end of the second rotation shaft, and the angle of the second rotation shaft with respect to the horizontal plane is large. It is configured to be larger than that of the first rotation axis.
The said, which is between the downstream end of the first blade portion which is the most downstream in the toner transport direction of the first screw and the connection portion connected to the second transport path forming portion of the first transport path forming portion. A protruding portion is provided that protrudes from the region of the first transport path forming portion above the first rotating shaft toward the rotating axis of the first rotating shaft.
A toner transfer device characterized in that the protruding portion overlaps with the first blade portion when viewed in the direction of the rotation axis of the first rotation shaft. The protrusion has a width of the connection portion on the downstream side of the downstream end portion of the first rotation shaft in the toner transport direction of the first screw in the space formed by the first transport path forming portion. The toner transfer device according to claim 1, wherein the toner transfer device is projected so as to be narrower than the area of the area. The claim is characterized in that the protruding portion is located on the downstream side of the downstream end of the first rotating shaft in the direction of the rotating axis of the first rotating shaft in the toner transport direction of the first screw. The toner transfer device according to 1 or 2. The toner transfer device according to any one of claims 1 to 3, wherein the protruding portion protrudes in a direction orthogonal to the rotation axis of the first rotation axis. The protruding portion is a rotation axis of the first rotation axis in a direction orthogonal to the rotation axis of the first rotation axis with respect to a wall surface forming a space between the first transport path forming portion and the first screw. The toner transfer device according to any one of claims 1 to 4, wherein the toner is projected toward. The toner transfer device according to any one of claims 1 to 5, wherein a plurality of the protruding portions are provided. The protruding portion is a region of the first blade portion spirally provided on the outer periphery of the first rotation shaft above the rotation axis of the first rotation shaft, and the direction of the rotation axis of the first rotation shaft. The toner transfer device according to any one of claims 1 to 6, wherein the toner transfer device is characterized by facing the above. The protruding portion includes a downstream end portion of the first rotary shaft in the direction of the rotation axis of the first rotary shaft in the toner transport direction of the first screw and the second end portion of the second screw in the toner transport direction of the second screw. The toner transfer device according to any one of claims 1 to 7, wherein the toner transfer device is located between the upstream end of the rotating shaft and the rotary shaft. Any one of claims 1 to 8, wherein the protruding portion is formed so as to be continuous with a wall surface forming a space between the second transport path forming portion and the second rotating shaft. The toner transfer device according to the section. The first axis of rotation extends substantially horizontally.
The second rotary shaft according to any one of claims 1 to 9, wherein the second rotation shaft extends from the upstream side to the downstream side in the toner transport direction of the second screw in a direction opposite to the direction of gravity. Toner transfer device. The toner according to any one of claims 1 to 10, wherein the first transport path forming portion has a degassing portion for releasing pressure in a space formed between the first transport path forming portion and the first rotating shaft. Conveyor device. An image forming part that forms an image on a recording material using toner,
A storage unit that stores toner and
A toner transporting unit that transports toner from the accommodating portion to the image forming unit,
In an image forming apparatus including
An image forming apparatus according to any one of claims 1 to 11, wherein the toner transporting unit is the toner transporting device.

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