JP7837735B2 - Toner transport device and image forming apparatus - Google Patents

Description

This invention relates to a toner transport device and an image forming apparatus equipped with a toner transport device.

Electrophotographic image forming apparatuses (hereinafter referred to as "image forming apparatuses"), such as printers using the electrophotographic process, may be equipped with a toner transport device. For example, a toner transport device may be provided to transport toner supplied to a developing device, or to transport toner remaining on image carriers such as photosensitive drums and transfer belts after image formation. Toner transport devices are known to include stirring members for agitating the toner contained within a toner container, and transport members for transporting the toner in and out of the container.

In the configuration disclosed in Patent Document 1, a film-like stirring member is provided on the rotating shaft inside the toner container. The tip of the stirring member contacts and bends against the inner surface of the toner container, and rotates while sliding against the inner surface of the toner container.

Japanese Patent Publication No. 2019-174724

In this type of configuration, the rotating shaft is often made of resin. However, depending on the rigidity of the rotating shaft, the thickness of the stirring element, and the distance between the tip of the stirring element and the inner surface of the toner container, the rotating shaft may bend due to the reaction force the stirring element receives from the inner surface of the toner container. Furthermore, if the rotating shaft is stored for a long period in a high-temperature environment while the stirring element is receiving this reaction force from the inner surface of the toner container, the rotating shaft may undergo creep deformation. If this creep deformation causes the rotating shaft to bend away from the inner surface of the toner container, the toner transport force provided by the rotating shaft and the transport element may decrease.

Therefore, the object of the present invention is to provide a toner transport device and an image forming apparatus that can stabilize toner transport force over a long period of time.

To achieve the above objective, the toner transport apparatus of the present invention is
A container capable of holding toner,
A rotating member rotatably provided inside the container and extending in the direction of the rotation axis, having a protruding portion that protrudes in a direction perpendicular to the direction of the rotation axis,
A flexible, sheet-like stirring member is provided on the outer circumference of the rotating member, with one end fixed to the rotating member, and the stirring member is capable of stirring the toner as the rotating member rotates.
Equipped with,
The stirring member comes into contact with the inner surface of the container and deforms as the rotating member rotates.
When the rotating member is viewed in a cross-section perpendicular to the axis of rotation, the rotational trajectory formed by the rotation of the rotating member, in which the free end of the stirring member is in contact with the inner surface of the container and is not deformed, has a radius equal to the line segment connecting the free end and the center of rotation of the rotating member.
If the phase in which the free end contacts the inner surface of the container and deforms is defined as the first phase, and the phase in which the free end does not contact the inner surface of the container is defined as the second phase,
When the rotational trajectory is divided into two by a first straight line parallel to the extension direction of the stirring member and passing through the center of rotation of the rotating member, and the free end is positioned in the first phase, the region on the opposite side of the first straight line from the first region where the free end is located is defined as the second region.
The aforementioned protrusion is
The rotating member is partially provided in the circumferential direction, and at least a portion of it is located in the second region where a second straight line perpendicular to the first straight line and passing through the center of rotation of the rotating member intersects the rotation trajectory in the direction of the rotating member,
In the first phase, when the stirring member is deformed, the second position is located in the second region when the third straight line, which is perpendicular to the tangent line passing through the point of contact formed between the inner surface of the container and the stirring member and passes through the center of rotation, is bisected by a third straight line, and the third straight line intersects the rotation trajectory.
It is placed between them ,
The container has a contact portion on its inner surface that comes into contact with the stirring member,
The protruding portion is configured to protrude from the outer circumferential surface of the rotating member toward the inner surface of the container, and to be located in a region substantially opposite to the contact portion on the outer circumference of the rotating member with respect to the axis of rotation, and to contact the inner surface separated from the contact portion when the rotating member is stopped and the stirring member is in contact with the contact portion, and to separate from the inner surface separated from the contact portion while the rotating member is rotating .
To achieve the above objective, the image forming apparatus of the present invention is
An image forming unit including an image carrier that holds a toner image, and a transfer means for transferring the toner image from the image carrier to a transfer target,
A cleaning means for removing toner from the image carrier,
A toner recovery device that recovers the toner removed from the image carrier by the cleaning means,
In an image forming apparatus comprising,
The toner recovery device is characterized by comprising the toner transport device of the present invention.

According to the present invention, the toner transport force of a toner transport device can be stabilized over the long term.

A schematic cross-sectional view showing the general configuration of the image forming apparatus according to this embodiment. A schematic perspective view showing the general configuration of the intermediate transfer unit. Schematic diagram showing the drive side configuration of the intermediate transfer unit. A schematic cross-sectional view showing the general configuration of the cleaning means. A schematic perspective view showing the configuration of the stirring mechanism. A schematic cross-sectional view showing the general configuration of the cleaning means. A schematic cross-sectional view showing toner transport in a cleaning device. A schematic cross-sectional view showing the general configuration of the cleaning means. A diagram showing the stirring shaft and stirring member in Example 1. Schematic diagram showing an example of the shape of the protruding part. A schematic diagram showing an example of the shape of the axis of rotation. A schematic perspective view showing the configuration of the stirring mechanism. Schematic view showing part of the stirring mechanism Schematic perspective view of the container body A schematic enlarged view showing the longitudinal center of the container body. A schematic cross-sectional view showing the configuration of the toner transport unit. Schematic perspective view of the container body Diagram illustrating the formation position of the protrusion in Example 1 A diagram showing the stirring shaft and stirring member in Example 2.

The embodiments for carrying out this invention will be described in detail below with reference to the drawings, based on examples. However, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments should be appropriately modified depending on the configuration and various conditions of the device to which the invention is applied. In other words, the scope of this invention is not intended to be limited to the following embodiments.

(Example 1)
[Image forming apparatus]
Figure 1 is a schematic cross-sectional view showing the configuration of the image forming apparatus 100 in this embodiment. The image forming apparatus 100 in this embodiment is a so-called tandem-type image forming apparatus (full-color laser printer) equipped with multiple image forming units Sa to Sd. The first image forming unit Sa forms an image using yellow (Y) toner, the second image forming unit Sb uses magenta (M), the third image forming unit Sc uses cyan (C), and the fourth image forming unit Sd uses black (Bk) toner. These four image forming units are arranged in a line at regular intervals, and the configuration of each image forming unit is substantially common in many parts, except for the color of the toner they contain. Therefore, in the following description, unless there is a need to distinguish between them, the subscripts a, b, c, and d given to the reference numerals in the figure to indicate that an element is provided for one of the colors will be omitted and the description will be generalized.

The image forming unit S (Sa, Sb, Sc, Sd) comprises a photosensitive drum 1 (1a, 1b, 1c, 1d), which is a drum-shaped photoreceptor; charging rollers 2 (2a, 2b, 2c, 2d) as charging means for charging the photosensitive drum 1; developing means 4 (4a, 4b, 4c, 4d); and drum cleaning means 6 (6a, 6b, 6c, 6d) (cleaning device). In this embodiment, the photosensitive drum 1, charging rollers 2, developing means 4, and drum cleaning means 6 are integrally formed into a process cartridge 19 (19a, 19b, 19c, 19d) that is detachable from the main body of the image forming apparatus 100.

The photosensitive drum 1 is an image carrier that holds the toner image and is driven to rotate at a predetermined process speed in the direction of the arrow R1 shown in the figure. The developing means 4 contains toner as a developer (a non-magnetic single-component developer in this embodiment) and includes developing rollers 41 (41a, 41b, 41c, 41d) as developing members for developing a toner image on the photosensitive drum 1 using the toner, and a developing coating blade (not shown) as a developer regulating member. The toner contained in the developing means 4 is carried on the developing rollers 41 at a position where the developing coating blade and the developing rollers 41 face each other, and then transported to the point where the photosensitive drum 1 and the developing rollers 41 face each other (developing section) as the developing rollers 41 rotate.

The drum cleaning means 6 is a means for recovering toner adhering to the photosensitive drum 1. The drum cleaning means 6 includes cleaning members such as a fur brush or cleaning blade that contact the photosensitive drum 1, and a waste toner container that contains the toner removed from the photosensitive drum 1 by the cleaning members.

The exposure means 3 can be composed of a laser scanner unit that scans laser light using a multifaceted mirror, or an LED array, but in this embodiment, a laser scanner unit is used. As will be described in detail later, the exposure means 3 forms an electrostatic latent image on the surface of the photosensitive drum 1 by irradiating the photosensitive drum 1 with a scanning beam 18 (18a, 18b, 18c, 18d) modulated based on an image signal.

When the control means (not shown) receives an image signal and the image forming operation is started, the photosensitive drum 1 is driven to rotate. During the rotation process, the photosensitive drum 1 is uniformly charged to a predetermined potential (charging potential) with a predetermined polarity (negative polarity in this embodiment) by a charging roller 2 to which a voltage is applied from a charging power supply (not shown), and is irradiated with a scanning beam 18 corresponding to the image signal from the exposure means 3. As a result, electrostatic latent images corresponding to the color component images of the target color image are formed in each image forming unit S. Next, at the development position, these electrostatic latent images are developed by a developing roller 41 to which a voltage is applied from a developing power supply (not shown), and are visualized as a toner image on the photosensitive drum 1.

In this embodiment, the normal charge polarity of the toner contained in the developing means 4 is negative. In this embodiment, the electrostatic latent image is reversed and developed using toner charged with the same polarity as the charge polarity of the photosensitive drum 1 by the charging member 2. However, the present invention can also be applied to an image forming apparatus that performs positive development of the electrostatic latent image using toner charged with the opposite polarity to the charge polarity of the photosensitive drum 1.

The intermediate transfer belt 71 (image carrier), which is an endless and movable intermediate transfer body, is positioned in contact with each photosensitive drum 1 of each image forming unit S and is stretched by three rollers: a drive roller 72, a tension roller 73, and a driven roller 74. The intermediate transfer belt 71 is stretched with a predetermined tension applied by the tension roller 73 and moves in the direction of arrow R2 in the diagram by the rotation of the drive roller 72, which rotates under driving force. As will be described in detail later, the intermediate transfer belt 71 in this embodiment is composed of multiple layers.

The toner image formed on the photosensitive drum 1 is primarily transferred to the intermediate transfer belt 71 during the process of passing through the primary transfer section N1 (N1a, N1b, N1c, N1d) where the photosensitive drum 1 and the intermediate transfer belt 71 come into contact. At this time, a voltage with the opposite polarity to the normal charging polarity of the toner (positive polarity in this embodiment) is applied to the primary transfer rollers 5 (5a, 5b, 5c, 5d) from a primary transfer power supply (not shown). Subsequently, any toner remaining on the photosensitive drum 1 without being primarily transferred to the intermediate transfer belt 71 is removed from the surface of the photosensitive drum 1 by the drum cleaning means 6. Here, the primary transfer rollers 5 are primary transfer members (contact members) positioned corresponding to the photosensitive drum 1 via the intermediate transfer belt 71 and in contact with the inner circumferential surface of the intermediate transfer belt 71.

In this way, the toner images of each color formed in each image forming unit S are sequentially transferred onto the intermediate transfer belt 71 in each primary transfer unit N1. As a result, four toner images corresponding to the desired color image are formed on the intermediate transfer belt 71.

In conjunction with the formation of an electrostatic latent image on the photosensitive drum 1 by the exposure means 3, the transfer material P (recording material), which is loaded in the paper feed cassette 11 (which serves as the storage unit), is fed by the paper feed roller 12 (which serves as the paper feed means) and then transported to the transport roller 13. Then, in time with the moment when the four-color toner images supported on the intermediate transfer belt 71 reach the secondary transfer section N2 formed by the contact between the secondary transfer roller 8 and the intermediate transfer belt 71, the transfer material P is transported to the secondary transfer section N2 by the transport roller 13. Afterward, the four-color toner images supported on the intermediate transfer belt 71 are simultaneously transferred to the surface of the transfer material P, such as paper or an OHP sheet, fed by the paper feed roller 12.

The secondary transfer roller 8 is in contact with the outer circumferential surface of the intermediate transfer belt 71 and is pressed with a force of 50 N against the drive roller 72, which is positioned opposite the secondary transfer roller 8 via the intermediate transfer belt 71, thereby forming the secondary transfer section N2. The four-color toner images supported on the intermediate transfer belt 71 are transferred simultaneously to the surface of the transfer material P as they pass through the secondary transfer section N2. At this time, a voltage with the opposite polarity to the normal charging polarity of the toner (positive polarity in this embodiment) is applied to the secondary transfer roller 8 from a secondary transfer power supply (not shown). This configuration related to secondary transfer corresponds to the transfer means of the present invention.

The transfer material P, onto which the four toner images have been transferred by secondary transfer, is then heated and pressurized in the fixing device 10, which acts as a fixing means. This melts and mixes the four toners, fixing them to the transfer material P. Toner remaining on the intermediate transfer belt 71 after secondary transfer is cleaned and removed by a cleaning means 9 (recovery means) located downstream of the secondary transfer section N2 in the direction of movement of the intermediate transfer belt 71.

The cleaning means 9 is a recovery member that contacts the outer circumferential surface of the intermediate transfer belt 71 at a position opposite the drive roller 72, and has an elastic cleaning blade 91 made of urethane rubber or the like. The toner recovered from the surface of the intermediate transfer belt 71 by the cleaning blade 91 is conveyed toward a recovery container 75 located within the area formed by the inner circumferential surface of the intermediate transfer belt 71, and is collected in the recovery container 75. In the following description, the cleaning blade 91 will be simply referred to as the blade 91. The blade 91 is positioned opposite the drive roller 72 via the intermediate transfer belt 71. Furthermore, the blade 91 contacts the intermediate transfer belt 71 in a counter-direction relative to the direction of movement of the intermediate transfer belt 71. The detailed configuration of the cleaning means 9 and the recovery container 75 will be described later.

In this embodiment of the image forming apparatus 100, a full-color print image is formed by the above operation.

In this embodiment, the image forming apparatus 100 is transported vertically upward relative to the secondary transfer section N2 with respect to gravity. Furthermore, in this embodiment, as shown in Figure 1, the cleaning means 9 is positioned above the drive roller 72 with respect to gravity.

Furthermore, in the image forming apparatus 100 of this embodiment, the intermediate transfer belt 71, cleaning means 9, and recovery container 75 are integrated into a single unit and are configured to be detachably attached to the main body of the image forming apparatus 100 as an intermediate transfer unit 7.

The above explanation of the image forming operation in the image forming apparatus 100 of this embodiment was based on an example using four image forming units Sa to Sd to form an image. However, the image forming apparatus 100 can also form single-color or full-color images by performing image forming using one or more (but not all) desired image forming units S.

[Intermediate Transfer Unit]
The configuration of the intermediate transfer unit 7 will be explained using Figures 2, 3, and 4. Figure 2 is a schematic perspective view showing the general configuration of the intermediate transfer unit 7. For the sake of simplicity, the intermediate transfer belt 71 is omitted from Figure 2. Figure 3(a) is a schematic diagram of the intermediate transfer unit 7 in Figure 2 as viewed from the direction of arrow AA (AA side), and is a simplified exploded schematic diagram explaining the configuration of the cleaning means 9. Figure 3(b) is a schematic cross-sectional view showing the general configuration of the toner transport path from inside the toner transport section 92 through the toner transport path 761 to the inlet 763 of the recovery container 75. Figure 4 is a schematic cross-sectional view of the cross section C of the intermediate transfer unit 7 in Figure 2 as viewed from the direction of arrow BB.

As shown in Figure 2, the intermediate transfer unit 7 supports the intermediate transfer belt 71 by three tension rollers: a drive roller 72, a tension roller 73, and a driven roller 74. The drive roller 72 is rotatably supported at both ends by bearings 721, and rotates when a predetermined rotational driving force is transmitted from the main body of the device to one end in the direction of the rotation axis. In the following description, the side to which the drive is transmitted will be referred to as the drive side (downstream side in the direction of arrow AA in Figure 2), and the opposite side will be referred to as the non-drive side (downstream side in the direction of arrow BB in Figure 2). In this embodiment, the drive roller 72 is a roller obtained by press-fitting metal shafts such as SUS into both ends of a pipe with a diameter of about 25 mm, which is made of an aluminum core covered with rubber in which carbon is dispersed as a conductive agent.

In this embodiment, the tension roller 73 is an aluminum metal rod with a diameter of approximately 25 mm, and bearings 731 are provided at both ends of the tension roller 73 in the direction of its rotational axis. The bearings 731 are biased by a compression spring 732, thereby biasing both ends of the tension roller 73 and applying a predetermined tension to the intermediate transfer belt 71. The driven roller 74 is also an aluminum metal rod, similar to the tension roller 73, and is rotatably supported at both ends by bearings 741.

A primary transfer roller 5 is provided at a position corresponding to the photosensitive drum 1, sandwiching the intermediate transfer belt 71. The primary transfer roller 5 is supported at both ends in the direction of its rotational axis by bearings 51 (51a, 51b, 51c, 51d). It is biased toward the intermediate transfer belt 71 with a predetermined force by compression springs 52 (52a, 52b, 52c, 52d) via the bearings 51, and rotates in conjunction with the rotation of the intermediate transfer belt 71. In this embodiment, the primary transfer roller 5 is made of a metal shaft, such as SUS, with a diameter of approximately 6 mm. At least one of the bearings 51 at both ends is made of a conductive material. By applying a positive voltage to the primary transfer roller 5 from a primary transfer power supply (not shown), the toner image is primarily transferred from the photosensitive drum 1 to the intermediate transfer belt 71.

Furthermore, rubber, resin, or other materials can be used as the material for the intermediate transfer belt 71. In this embodiment, the intermediate transfer belt 71 was an endless belt-shaped film molded from a resin material having a medium resistance of approximately 60 μm in thickness in the thickness direction perpendicular to the movement direction of the intermediate transfer belt 71 and the rotation axis direction of each tension roller.

The frame 76 is the frame of the intermediate transfer unit 7 for supporting each tension roller, and is made of molded resin material. The bearings 51 at both ends supporting the primary transfer roller 5, and the bearings 731 at both ends supporting the tension roller 73, are supported on the frame 76 in a manner that allows them to move relative to the frame 76 in the direction of pressure application of each compression spring.

Near the drive roller 72 supported by the frame 76, support plates 77 and 78 are provided, respectively, to rotatably support the drive roller 72 and the driven roller 74 via bearings. Support plates 77 and 78 are fixed to the frame 76 by screws or the like at both ends in the direction of the drive roller 72's rotation axis, positioning them accordingly. In this embodiment, press-formed sheet metal is used for support plates 77 and 78.

As will be described in detail later, as shown in Figures 2 to 4, the cleaning means 9, as a toner recovery device, includes a blade 91 as a cleaning member and a toner transport unit 92 that recovers and transports the toner removed from the intermediate transfer belt 71 by the blade 91. The blade 91 and the toner transport unit 92 are fixed in a positioned manner on support plates 77 and 78, respectively.

The toner removed from the intermediate transfer belt 71 by the blade 91 is temporarily stored inside the toner transport unit 92. Then, as shown in Figure 3(b), after being transported inside the toner transport unit 92, it is collected into the recovery container 75 via the toner transport path 761 provided on the drive side of the frame 76. As shown in Figure 3(a), the toner transport path 761 is sealed by fastening the transport path cover 762 to the container body 94 with screws or the like, preventing toner from leaking to the outside in the intermediate transfer unit 7.

The toner collection container 75 is constructed from molded resin parts, with multiple resin parts bonded together to form a sealed container. The collection container 75 is fixed to the frame 76 by screws or the like. The collection container 75 is also equipped with a detection means (not shown), such as an optical sensor, to detect when the container is full of toner. This allows the user to be notified when it is time to replace the collection container 75. When the collection container 75 is full, it can be replaced with a new one by a service technician or the user by replacing the intermediate transfer unit 7.

[Cleaning methods]
As shown in Figures 2 to 4, the cleaning means 9, as described above, includes a blade 91 as a cleaning member and a toner transport unit 92 for temporarily storing the toner removed from the intermediate transfer belt 71 by the blade 91 and transporting it to the collection container 75. As shown in Figure 4, the blade 91 has an elastic urethane rubber 91a and a retaining sheet metal 91b to which the urethane rubber 91a is bonded. With respect to the longitudinal direction of the urethane rubber 91a (the direction of the rotation axis of the drive roller 72), the length of the urethane rubber 91a is set to be wider than the image forming region on the intermediate transfer belt 71 in which a toner image can be carried. The blade 91 is also positioned in pressure contact with the intermediate transfer belt 71 and is capable of removing toner remaining on the intermediate transfer belt 71.

To reliably remove the toner, the blade 91 must be pressed against the intermediate transfer belt 71 at a predetermined pressure. In this embodiment, the predetermined pressure is ensured by positioning the blade 91 opposite at least one of the tension rollers that tension the intermediate transfer belt 71. More specifically, the blade 91 is positioned downstream of the secondary transfer section N2 in the direction of movement of the intermediate transfer belt 71, and above the drive roller 72 in the direction of gravity, so as to be in contact with the drive roller 72.

With respect to the longitudinal direction of the blade 91, both ends of the retaining sheet metal 91b are provided with holes 91c for rotatably supporting the blade 91, and spring attachment points 91d for attaching a pressure spring to press the blade 91 against the intermediate transfer belt 71. The blade 91 engages with metal blade support shafts 77a and 78a, respectively, crimped to the support plates 77 and 78, via the holes 91c at both ends, and is supported in a rotatable state, freely moving toward and away from the intermediate transfer belt 71.

Furthermore, the spring attachment portions 91d provided at both longitudinal ends of the blade 91 and the spring attachment portions 94d provided at both longitudinal ends of the container body 94 constituting the toner transport section 92 engage with hooks 93a and 93b provided at both ends of the tension spring 93 in the direction of extension and contraction, respectively. More specifically, as shown in Figures 3 and 4, the spring attachment portion 91d engages with hook 93a, and the spring attachment portion 94d engages with hook 93b, so that the spring attachment portions 91d and 94d are connected by the tension spring 93. As a result, the tension spring 93 generates a moment around the hole 91c on the blade 91, causing it to press against the intermediate transfer belt 71 with a predetermined pressure.

In the toner transport section 92, to prevent toner recovered from the intermediate transfer belt 71 from leaking out of the container body 94, several sealing members (not shown) are attached to the container body 94 using double-sided tape or the like. Furthermore, regarding the direction of movement of the intermediate transfer belt 71, a sheet member 44 is provided upstream of the cleaning section CL where the blade 91 and the intermediate transfer belt 71 come into contact, to contact the intermediate transfer belt 71 and seal the gap between the toner transport section 92 and the intermediate transfer belt 71. The sheet member 44, acting as a sealing member, extends in the width direction of the intermediate transfer belt 71. With these configurations, the toner temporarily contained in the toner transport section 92 is transported to the recovery container 75 without leaking out of the cleaning means 9.

<Toner transport in the toner transport section>
As shown in Figure 4, the toner transport unit 92, which serves as a toner transport device, comprises a container body 94, a stirring means 97, and a screw 98. The container body 94 is configured to temporarily contain the toner removed by the blade 91. The stirring means 97 consists of a rotating shaft 95 as a rotating member rotatably provided inside the container body 94, and a flexible sheet-like stirring member 96, and stirs and transports the toner contained in the container body 94. The screw 98 has a rotating shaft 98a arranged parallel to the rotating shaft 95 of the stirring means 97, and a blade portion 98b that extends spirally around the outer circumference of the rotating shaft 98a relative to its axis (see Figure 3(b)). The screw 98 is a transport member that, by rotating, transports the toner contained in the container body 94 to the collection container 75.

After passing through the secondary transfer section N2, the toner removed from the intermediate transfer belt 71 by the blade 91 accumulates in the toner transport section 92, specifically in the cleaning section CL where the blade 91 and the intermediate transfer belt 71 come into contact, and around the sheet member 44. The toner accumulated in the toner transport section 92 is then agitated by the rotating agitator 97 and supplied to the screw 98.

The configuration of the stirring means 97 will be described with reference to Figure 5. Figure 5 is a perspective view of the stirring means 97. As mentioned above, the stirring means 97 consists of a rotating shaft 95 and a stirring member 96. The rotating shaft 95 is made of a resin material and has a hole 95b on one end in the direction of rotation that engages with an unshown shaft provided in the container body 94, and an engagement portion 95c on the other end that engages with the gear 82 shown in Figure 2. The rotating shaft 95 rotates in the clockwise direction in Figure 4 by sequentially transmitting driving force from gears 80, 81, and 82, which are arranged on an axis parallel to the drive roller 72. As shown in Figure 4, the rotating shaft 95 has at least one flat portion a1 which is a flat portion parallel to the axial direction, and one end of the stirring member 96 is fixed to the flat portion a1 by double-sided tape or the like (not shown). The stirring member 96 is a flexible sheet material such as PET with a thickness of approximately 80 μm, extending throughout the entire interior of the toner transport section 92 in the longitudinal direction of the blade 91, and rotating together with the rotating shaft 95. Furthermore, a projection 95a is provided approximately in the center of the rotating shaft 95 in the longitudinal direction, extending in a portion of the circumferential direction.

The mechanism for supplying toner to the screw 98 by the stirring means 97 will be explained using Figures 6, 7(a), and 7(b). Figure 6 is a schematic cross-sectional view showing the moment when the free end of the stirring member 96 separates from the inner wall 94h, which is part of the container body 94, when viewed from the direction of the rotation axis of the rotating shaft 95. This corresponds to the cross-section C in Figure 2 when viewed from the direction of the arrow BB. Figures 7(a) and 7(b) are schematic cross-sectional views illustrating toner transport when viewed from the same direction as Figure 6. Figure 7(a) shows the state in which the inner wall 94h, which is part of the container body 94, and the stirring member 96 are in contact, i.e., the first phase (sliding phase), and Figure 7(b) shows the state in which contact between the inner wall 94h and the stirring member 96 is released, i.e., the second phase (non-sliding phase).

The inner surface of the container body 94 (toner transport section 92) that forms the toner transport path (toner storage section) has a shape in which the distance between it and the rotation axis of the rotating shaft 95 in a direction perpendicular to the rotation axis of the rotating shaft 95 changes around the rotation axis (in the direction of rotation of the rotating shaft 95). Due to this change in the inner surface shape of the container body 94, the stirring member 96 has a first phase (sliding phase) in which the tip (other end), which is the free end opposite to the fixed end (one end) attached to the rotating shaft 95, contacts the inner surface of the container body 94, and a second phase (non-sliding phase) in which it does not contact.
It is configured to allow for the following:

The circle Rm shown in Figure 6 is the virtual trajectory of the free end, which is the end (tip) of the stirring member 96 that is not fixed to the rotation axis 95, when the stirring member 96 rotates together with the rotation axis 95. In other words, it is the virtual rotation trajectory of the free end, represented by a circle with a radius equal to the distance from the rotation center of the rotation axis 95 to the free end of the stirring member 96, when the stirring member 96 is not subjected to external forces due to contact with surrounding parts. The inner wall 94h has a concave curved surface portion 94r centered on the rotation center of the rotation axis 95, where _rh is the radius of the curved surface portion 94r. In the state shown in Figure 6, at the moment the free end of the stirring member 96 separates from the inner wall 94h, the free end is on the rotation trajectory Rm, and in the phase where the free end does not contact the container body 94 (non-sliding phase), the free end rotates clockwise along the rotation trajectory Rm. On the other hand, a portion of the upper surface of the urethane rubber 91a and a portion of the inner wall 94h and inner wall 94i of the container body 94 are located inside the rotation trajectory Rm as contact points. Therefore, as shown in Figure 7(a), in a phase (sliding phase) where the upper surface of the urethane rubber 91a and the inner wall 94h are located inside the rotation trajectory Rm opposite the free end of the stirring member 96, the stirring member 96 comes into contact with them and rotates while bending.

The free end of the stirring member 96, which is in contact with the inner wall 94h, rotates in a deformed state (first state) that is deformed upstream with respect to the rotational direction of the stirring member 96. At this time, since the stirring member 96 rotates while remaining in contact with the inner wall 94h, the toner on the upper surface of the stirring member 96 is scooped up while being prevented from falling from the inner wall 94 side. In other words, the stirring member 96 scoops up the toner accumulated on the sheet member 44 that is radially inward of the rotational trajectory Rm, and scrapes off the toner accumulated on the upper surface of the urethane rubber 91a. While holding the recovered toner, the stirring member 96 rotates along the inner wall 94h.

On the other hand, toner accumulated near the sheet member 44, radially outside the rotation trajectory Rm, continues to remain on the upper side of the sheet member 44 in the direction of gravity. When toner is further collected by the blade 91 in this state, the toner remaining on the sheet member 44 is pushed upward in the direction of gravity by the toner removed from the intermediate transfer belt 71 by the blade 91. When the toner reaches the inside of the rotation trajectory Rm, it is scooped up by the rotating agitator 96. In this way, the toner remaining on the sheet member 44 is sequentially replaced.

Then, as the stirring member 96 rotates further clockwise from the position shown in Figure 7(a), it reaches the phase shown in Figure 6 (non-sliding phase), and the tip of the free end separates from the inner wall 94h. The free end of the stirring member 96, separated from the inner wall 94h, enters a free state (second state) where the deformation caused by contact with the inner wall 94h is released due to the switch from the sliding phase to the non-sliding phase. Then, as shown in Figure 7(b), some of the toner T scooped up by the stirring member 96 is propelled from the stirring member 96 towards the screw 98 by the reaction of the stirring member 96 returning from the deformed state to the free state. After reaching the screw 98, the propelled toner T is transported towards the toner transport path 761 by the transport section 60 of the rotating screw 98. Furthermore, any toner that did not fly away due to the recoil of the stirring member 96 returning to its free state falls onto the top surface of the urethane rubber 91a, as indicated by the arrow in Figure 7(b), and is then scooped up again by the rotating stirring member 96.

In the transport section 60, the toner T transported in the direction of arrow BB in Figure 2 with respect to the rotation axis of the screw 98 reaches the toner transport path 761. As shown in Figure 3(a), the toner transport path 761 is formed with a slope angle greater than the angle at which the toner T falls under its own weight. As a result, as shown in Figure 3(b), the toner T transported to the toner transport path 761 by the rotation of the screw 98 falls under the inlet 76 of the collection container 75 under its own weight.
The toner is transported up to 3. The toner T that has been transported up to the inlet 763 is then diffused and filled inside the collection container 75 by a toner diffusion member (not shown) placed in the collection container 75 in order to fill the inside of the collection container 75 with toner.

<Creep deformation of stirring means>
As described above, the stirring member 96 comes into contact with the inner wall 94h and wall 94i that constitute the toner transport section 92 within the rotational trajectory Rm, and deforms. At this time, the stirring member 96 and the rotating shaft 95 receive reaction forces from these walls. As described above, since the rotating shaft 95 is made of resin, it may undergo creep deformation if stored at high temperatures for a long period of time while subjected to reaction forces. When the rotating shaft is driven under such circumstances, the rotating shaft 95 rotates with a deflection approximately opposite to the contact point between the stirring member 96 and the wall 94i that receives the reaction force.

Figure 8(a) is a schematic cross-sectional view showing the stirring member 96 in contact with the inner wall 94i and receiving a reaction force F. Figure 8(b) is a schematic cross-sectional view showing the situation when creep deformation occurs in the rotating shaft 95 in that state. Point O in Figures 8(a) and 8(b) is the rotation center of the rotating shaft 95 when creep deformation has not occurred.

As mentioned above, a portion of the inner wall 94i is positioned on the inside of the rotation trajectory Rm. This is because the conveying unit 60 is positioned close to the rotating shaft 95 in order to efficiently transfer the toner T flying from the stirring member 96 toward the screw 98 to the conveying unit 60. The inner wall 94i, which is continuous with the conveying unit 60, is configured such that its upstream end in the rotational direction of the rotating shaft 95 is positioned on the inside of the rotation trajectory Rm.

As shown in Figure 8(a), when the stirring member 96 receives a reaction force from the inner wall 94i, the rotating shaft 95 to which the stirring member 96 is fixed also receives a force via the stirring member 96. Here, since the rotating shaft 95 is made of resin, if it is stored at high temperatures for a long period of time in this state, it may undergo creep deformation. In that case, it is thought that the axial center of the rotating shaft 95 will bend in approximately the same direction as the reaction force F, starting from both axial ends that are rotatably supported. This state is shown in Figure 8(b), which is a cross-section at the point where the amount of axial deflection is greatest. Since the deformation of the rotating shaft 95 is due to the reaction force of the force with which the deformed stirring member 96 tries to restore itself, point OO, which is the center of the rotating shaft 95 in the cross-section of Figure 8(b), is pushed approximately opposite to the free end of the stirring member 96. When the rotating shaft 95 rotates in this state, the rotating shaft 95 in the cross-section of Figure 8(b) will rotate with its center shifted by the distance between point O and point OO. When the rotating shaft 95 rotates with this shifted center, the amount of penetration into the inner walls 94h, 94i and the upper surface of the urethane rubber 91a, which were in contact with the free end of the stirring member 96 during rotation, will decrease by the amount of the shift in the center of rotation.

The circle Rmx shown in Figure 8(b) represents the virtual movement trajectory of the free end of the stirring member 96 when the stirring member 96 rotates with the rotation axis 95 in the cross-section shown in Figure 8(b), with point O as the center. That is, it represents the virtual rotation trajectory of the free end, represented by a circle with a radius equal to the distance from the rotation center of the rotation axis 95 to the free end of the stirring member 96, when the stirring member 96 is not subjected to external forces due to contact with surrounding parts in the cross-section shown in Figure 8(b). The radius of the rotation trajectory Rmx is smaller than the rotation trajectory Rm by the distance between point O and point OO, which is the displacement of the rotation center.

Furthermore, if the amount of deflection of the rotating shaft 95 and the amount of displacement of the center of rotation are large, and the inner wall 94h does not enter the inside of the rotation trajectory Rmx, then in the cross-section of Figure 8(b), the stirring member 96 and the inner wall 94h will not be in contact, and a gap will be created. Moreover, not limited to the above cross-section, a gap may also be created between the stirring member 96 and the wall 94h in similar cross-sections at positions where the deflection due to creep deformation of the rotating shaft 95 is large. In such cases, the toner transportability that was maintained by the stirring member 96 contacting the inner wall 94h will be impaired, and there is a risk that the toner transport force will decrease.

Here, for example, it is conceivable to suppress creep deformation by providing a bearing shape to support the rotating shaft 95 in the portion of the rotating shaft 95 that has a large deflection. However, since toner melting and solidification will occur when the toner exceeds a certain temperature, it is preferable to keep the sliding parts that generate frictional heat to a minimum. In the rotating shaft 95 within the toner transport section 92, toner that has entered the gap between the supported portion and the bearing portion of the rotating shaft 95 may melt due to frictional heat as it is continuously rubbed. Then, when the melted toner solidifies again, toner may adhere to the rotating shaft 95, potentially hindering normal rotation.

Therefore, in this embodiment, as shown in Figure 8, a projection 95a is provided on the rotating shaft 95 at a position approximately opposite the contact point between the stirring member 96 and the inner wall 94i of the toner transport section 92 (container body 94). The projection 95a protrudes toward the inner wall surface of the toner transport section 92 at a position approximately opposite the rotation axis of the rotating shaft 95 to the position where the stirring member 96, in its sliding phase, contacts the inner wall surface of the toner transport section 92. This configuration ensures that even if the rotating shaft 95 receives a reaction force from a part of the toner transport section 92 via the stirring member 96, the projection 95a contacts the inner wall 94h of the toner transport section 92, preventing further deformation.

The deflection deformation of the rotating shaft 95 is not limited to deformations that become fixed over time, such as the creep deformation described above, but may also include temporary deflection deformations that occur only while the stirring member 96 is receiving a reaction force from the inner wall of the toner transport section 92. In other words, due to the thickness, length, and material of the rotating shaft 95, the thickness and material of the stirring member 96, the shape and dimensions of the inner wall of the toner transport section 92, etc., the rotating shaft 95 may deflect significantly when it receives a reaction force from the inner wall of the toner transport section 92 when rotation stops. In particular, a deformation posture may be formed in which the longitudinal center of the rotating shaft 95 deflects relatively significantly. In such cases, the protrusion height from the outer surface of the rotating shaft 95 and its width in the direction of rotation may be set so that the protrusion 95a can contact the inner wall 94h of the toner transport section 92 to suppress the deflection described above or reduce the degree of deflection. On the other hand, the protruding portion 95a may be configured such that, for example, when rotation is resumed, the stirring member 96 no longer receives a reaction force from the inner wall of the toner transport section 92, thereby eliminating or reducing the deflection of the rotating shaft 95, and thus not coming into contact with (being separated from) the inner wall 94h, or the degree of contact with the inner wall 94h is reduced compared to when the unit is stopped. Alternatively, in cases where deflection occurs in the rotating shaft 95 regardless of whether the unit is stopped or rotating, the protruding portion 95a may be configured to always be in contact with the inner wall 94h while the stirring member 96 receives a reaction force from the inner wall of the toner transport section 92. In other words, while an elastic force is generated in the stirring member 96 due to the reaction force received from the inner wall of the toner transport section 92, the protruding portion 95a may always be configured to brace against and support the inner wall 94h. In such cases, it is preferable that the range in which the protrusion 95a is formed relative to the rotating shaft 95 (the range in which the protrusion 95a slides against the inner wall of the toner transport section 92), that is, the size and position of the protrusion 95a, be limited to the minimum necessary, so as not to obstruct the rotation of the rotating shaft 95.

Figure 18 is a schematic diagram illustrating the formation position and range of the protrusion 95a, showing a cross-section perpendicular to the rotation axis of the rotation axis of the rotation axis 95 at the longitudinal position (rotation axis direction position) where the protrusion 95a is provided on the rotation axis 95. The protrusion 95a is provided on the outer circumference of the rotation axis 95 in a region substantially opposite to the rotation axis (point O) with respect to the inner wall 94i that forms the contact portion (contact point) with the stirring member 96. More specifically, the protrusion 95a is formed so as to be located in a region opposite to the side where the contact portion is located, with respect to a second imaginary line C2 that is perpendicular to a first imaginary line C1 passing through the contact portion with the stirring member 96 on the inner wall 94i and the rotation axis (point O). Note that the protrusion 95a only needs to be formed to include at least the portion located in the region on the opposite side, and the shape of the other regions is arbitrary as long as it does not hinder the rotation of the rotation axis 95. Furthermore, in this embodiment, the projection 95a is formed with a width in the circumferential direction on the outer circumference of the rotating shaft 95 that is greater than 90 degrees in a phase range DD. That is, it is formed such that the angle between one end 95a1 and the other end 95a2 in the outer circumference direction is greater than 90 degrees around the axis of rotation (point O). Therefore, the projection 95a is formed to intersect the first imaginary line C1 and contacts the inner wall 94h at a position substantially opposite to the position where the stirring member 96 contacts the inner wall 94i, with the axis of rotation (point O) in between.

The configuration of the protrusion 95a shown here is merely an example. At a minimum, the protrusion 95a should be located in a region opposite to the side where the contact portion is located relative to the second imaginary line C2, and should be configured to contact the inner wall of the toner transport section 92 in such a way that the stirring member 96 can generate a force (including a component force acting in the opposing direction) that counteracts the reaction force F from the inner wall 94i of the toner transport section 92. Therefore, the configuration of the protrusion 95a can also be such that, for example, it does not intersect with the first imaginary line C1 but is formed near the second imaginary line C2, and still generate the opposing force. Such a configuration can also be adopted as the configuration of the protrusion 95a.

In this embodiment, the protruding portion 95a is configured to contact the curved portion 94r, which is part of the inner wall 94h, when the rotating shaft 95 receives a reaction force F from the inner wall 94i via the stirring member 96. The radius of Rm - r _h shown in Figure 6 is set to be greater than the clearance between the protruding portion 95a and the curved portion 94r when the stirring means 97 is not deformed. Here, the radius of Rm - r _h is the amount of penetration of the stirring member 96 into the curved portion 94r when the stirring means 97 is not deformed.

In other words, when r _a is the radial distance from the center of rotation to the contact point between the curved surface portion 94r of the protruding portion 95a,
(Rm radius - _{r h} ) > (r _h - _{r a} ) ... (1)
r _a > (radius of 2r _h - Rm) ... (2)
Set it so that it becomes like this.

By configuring the system as described above, even if the rotating shaft 95 receives a reaction force from a part of the toner transport section 92 and bends due to creep deformation, as shown in Figure 8(b), the stirring member 96 is ensured to reliably contact the curved surface 94r provided on the inner wall 94h.

Furthermore, as mentioned above, since toner melts above a certain temperature, it is preferable to minimize the amount of sliding parts that generate frictional heat. In particular, in this embodiment, since the fixing device 10 is directly above the cleaning unit 9, the toner in the toner transport unit 92 is susceptible to the heat generated in the fixing means. Therefore, it is necessary to further suppress the heat applied to the toner in the toner transport unit 92. In this embodiment, by making the protrusion 95a a portion rather than the entire length in the rotational direction, frictional heat caused by friction between the protrusion 95a and the toner transport unit 92, and between the toner interposed between the toner transport unit 92, is suppressed. In other words, when the rotation axis 95 is viewed from a cross-section perpendicular to the rotation axis, the central angle corresponding to the range of the protrusion 95a provided on the outer circumference of the rotation axis 95 is set to be smaller than 360°.

Here, as mentioned above, the rotating shaft 95 is pushed approximately opposite to the free end of the stirring member 96 by the reaction force F when the deformed stirring member 96 attempts to return to its original shape. Figure 9 shows an example of the state of the stirring shaft 95 and stirring member 96 when the stirring member 96 is in contact with the inner wall 94i. Figure 9(b) is a partial enlarged view of Figure 9(a). Figure 9(c) is an explanatory diagram of the area in which the protrusion 95a is provided in this embodiment.

The restoring force of the rotating shaft 95 at this time acts between the direction normal to the stretching direction of the undeformed stirring sheet 96 (dashed line s in Figure 9(b)) and the direction normal to the tangent at the contact end (contact point) α when the stirring member 96 contacts the inner wall 94i. Therefore, the protruding portion 95a only needs to be provided within the following range. That is, a straight line v passing through the center O of the rotating shaft 95 and perpendicular to the stretching direction of the undeformed stirring sheet 96 (dashed line s in Figure 9(b)) contacts the rotation trajectory Rm on the opposite side of the contact point (contact point) α between the stirring member 96 and the inner wall 94i and the center point O of the rotating shaft 95, and this point is called D (the first position). Then, a straight line w perpendicular to the tangent line (dotted line t in Figure 9(b)) at the contact point (contact point) α when the stirring member 96 contacts the inner wall 94i, contacts the rotation trajectory Rm on the opposite side of the contact point of the stirring member 96 from the center point O of the rotation axis 95, and this point is defined as E (the second position). When set in this way, the protruding portion 95a only needs to be at least partially between line segment OE and line segment OD in the rotation direction of the rotation axis 95.

Here, the greater the deflection of the stirring member 96, the larger the angle between line segment OE and line segment OD. In this embodiment, the stretching direction of the undeformed stirring sheet 96 is parallel to the flat portion a1, and the tangent at the contact point (contact point) of the stirring member 96 in the most deflected state, when the stirring member 96 is in contact with the inner wall 94i, is approximately perpendicular to the flat portion a1 shown in Figure 4. Therefore, the protrusion 95a in this embodiment is provided at the position described below. That is, as shown in Figure 9, on the outer circumference of the rotation shaft 95, on the side opposite to the center O of the rotation shaft 95 in a direction perpendicular to the flat portion a1, the protrusion 95a is provided in a range of approximately 90° from a position perpendicular to the center O with respect to the flat portion a1, in the direction opposite to the rotation direction of the stirring member 96, to the flat portion a1.

Furthermore, the range in which the protrusion 95a is provided will be explained in a different way. In Figure 9(c), let u be a line passing through the center O of the rotation axis 95, parallel to line s, and perpendicular to line w. Let the line passing through the center O of the rotation axis 95 and containing line u be the first line A, the line passing through the center O of the rotation axis 95 and containing line v be the second line B, the line passing through the center O of the rotation axis 95 and containing line w be the third line C, and the line passing through the center O of the rotation axis 95 and perpendicular to line C be D1. Furthermore, when line A is used as the boundary to divide the area into two, the region containing the planar portion a1 is defined as the first region, and the region extending from the first region across line A but not containing planar portion a1 is defined as the second region. In this case, the aforementioned first position D and second position E are located within the second region. Therefore, in this second region, as described above, it is sufficient that at least a part of the protrusion 95a is in the range DE between line segment OE and line segment OD.

While the fuser unit 10, equipped with a heating element such as a heater, represents a particularly typical heat source configuration within the image forming apparatus 100, the heat source that influences the toner in the image forming apparatus 100 is not limited to the fuser unit 10. For example, the motor used as a drive source, or the control unit equipped with a CPU and memory, can also be cited as heat sources.

Toner melts at temperatures above a certain level and solidifies again when the temperature drops. Therefore, toner adhering to moving parts can lead to damage to individual parts or the entire device. In contrast, the configuration of the stirring means 97 in this embodiment prevents heat generation due to friction, making it less likely for the toner inside the toner transport unit 92 to solidify, even when the ambient temperature around the toner transport unit 92 is high.

The protruding portion 95a is provided in a phase range that includes a phase opposite to the direction of action of the reaction force that the stirring member 96, which is in the sliding phase, receives from the inner surface of the toner transport section 92, in the rotational phase of the rotating shaft 95, across the rotational axis. In this embodiment, the protruding portion 95a protrudes from the outer circumferential surface of the rotating shaft 95 in a direction substantially perpendicular to the rotational axis, and is provided so as to extend along the rotational direction of the rotating shaft 95 on the outer circumferential surface of the rotating shaft 95. The side surface of the protruding portion 95a is a surface perpendicular to the rotational axis of the rotating shaft 95. Note that the shape of the protruding portion 95a is not limited to the shape adopted in this embodiment, and modified shapes such as those shown in Figures 10(a) to 10(c) are also acceptable.

The protrusion 95a1 of the modified example 1 shown in Figure 10(a) is provided so as to extend on the outer surface of the rotating shaft 95, inclined in a substantially helical manner with respect to the axis of rotation, taking into consideration the axial transport of toner, and its side surface is a curved surface that becomes part of the screw. The rotating shaft 95 rotates counterclockwise around the axis of rotation when viewed in the opposite direction (direction of arrow AA in Figure 2 (second direction)) to the direction in which the screw 98 transports toner (direction of arrow BB in Figure 2 (first direction)). The protrusion 95a1 is inclined such that its position in the rotational direction of the rotating shaft 95 changes from the upstream side to the downstream side as it moves in the opposite direction.

The protrusion 95a2 of Modified Example 2 shown in Figure 10(b) is provided on the outer circumferential surface of the rotating shaft 95, extending in a substantially helical manner relative to the rotational direction of the rotating shaft 95, similar to the protrusion 95a1 of Modified Example 1 in Figure 10(a), taking into consideration the axial transport of toner. The side surface of the protrusion 95a2 is composed of a plane extending in a direction inclined with respect to both the direction of the rotational axis and the direction perpendicular to the rotational axis, when viewed from a direction perpendicular to the rotational axis of the rotating shaft 95. The inclination direction of the side surface of the protrusion 95a2 is designed to consider the mold removal direction, and is parallel to the mold removal direction, which is perpendicular to the rotational axis. The shape of the protrusion 95a2 of Modified Example 2 in Figure 10(b) will be described in detail in Embodiment 2.

The protruding portion 95a3 of Modification 3 shown in Figure 10(c) has an uneven shape in which multiple protrusions are arranged in the direction of extension, such that multiple peaks of protrusion height are formed in the direction extending along the outer circumferential surface of the rotating shaft 95. While the number of protrusions is two in the configuration example shown in Figure 10(c), three or more may be provided, and the spacing between the protrusions (length of the recesses) in the direction of extension of the protruding portion 95a3 may be set as appropriate. This uneven shape may also be applied to the protruding portion 95a of Modification 1 shown in Figure 10(a) and the protruding portion 95a2 of Modification 2 shown in Figure 9(b).

Furthermore, in this embodiment, the protrusion 95a is provided at the center of the rotation axis 95 in the longitudinal direction (rotation axis direction), but this is not limited to this configuration. As shown in Figures 11(a) and 11(b), multiple protrusions 95a may be provided. That is, as shown in Figure 11(a), multiple protrusions may be provided not only at the center in the longitudinal direction, but also on both sides of the longitudinal direction at intervals in the longitudinal direction. Alternatively, as shown in Figure 11(b), multiple protrusions may be provided between the center and both ends in the longitudinal direction. From the viewpoint of preventing deflection of the rotation axis 95, it is preferable to provide them near the center, away from both ends in the longitudinal direction.

In the configuration shown in Figure 11(a), multiple protrusions 95a are arranged in the same phase, while in the configuration shown in Figure 11(b), multiple protrusions are arranged in different phases. According to the configuration in Figure 11(b), when the rotating shaft 95 receives a reaction force from the inner wall 94i of the toner transport section 92 via the stirring member 96, instead of a single protrusion 95 contacting the inner wall 94h to prevent deformation, multiple protrusions contact the inner wall 94h at different phases. This reduces toner friction per protrusion. The shape of the multiple protrusions is not limited to the shape of the protrusions 95a in this embodiment; the shapes of the modified protrusions shown in Figures 10(a) to 10(c) may also be adopted. Furthermore, a configuration combining multiple protrusions 95a from this embodiment with the modified protrusions shown in Figures 10(a) to 10(c) may also be used.

In this way, according to this embodiment, deformation of the rotating shaft can be suppressed in a stirring means equipped with a stirring member on the rotating shaft. This makes it possible to provide a toner transport device and an image forming apparatus that enable efficient toner stirring and transport, and that are less prone to toner solidification even in high-temperature environments.

In this embodiment, the configuration of this stirring means was applied to a cleaning means for the intermediate transfer belt in an image forming apparatus, but it is not limited to that. It can also be applied to configurations that contain toner and require stirring, such as cleaning means for developing devices or drums equipped with toner containers.

Furthermore, in this embodiment, the case where the free end of the stirring member 96 contacts a portion of the inner wall 94i of the toner transport unit 92, as this portion is located inside the rotation trajectory Rm, was described. It goes without saying that similar effects can be obtained when the free end of the stirring member 96 contacts a portion of the upper surface of the urethane rubber 91a or the inner wall 94h of the container body 94.

Furthermore, if the protrusion 95a comes into contact with the inner wall 94h due to the deflection of the rotating shaft 95, when the rotation of the rotating shaft 95 resumes, the downstream end of the protrusion 95a may interfere with the upstream end of the inner wall 94i, which is downstream of the inner wall 94h. However, since the protrusion 95a is provided in a configuration that covers only a very small area in the longitudinal direction of the rotating shaft 95, the reaction force received from the upstream end of the inner wall 94i and the rotational force of the rotating shaft 95 cause it to ride up onto the inner wall 94i, and it does not hinder the rotation of the rotating shaft 95. In other words, the protrusion 95a applies a force to the rotating shaft 95 that returns point OO, the rotation center of the rotating shaft 95, which had shifted due to deflection over time, back to point O, thereby eliminating the deflection of the rotating shaft 95.

(Example 2)
Embodiment 2 of the present invention will be described using Figures 12 to 17 and Figure 19. Note that Embodiment 2 differs from Embodiment 1 only in the shape of the container body and stirring means within the toner transport means 92; all other parts are the same as in Embodiment 1. The configurations common to Embodiment 1 will not be described.

In this embodiment, the toner transport unit is designated as the toner transport unit 920, the container body as the container body 940, the stirring means as the stirring means 970, the rotating shaft as 950, the protruding part corresponding to 95a in Embodiment 1 as 950a, and the parts corresponding to 95b and 95c as 950b and 950c.

Figure 12 is a schematic perspective view of the stirring means 970, and Figure 13 is a view taken from the direction of arrow d shown in Figure 12. The rotating shaft 950 is provided with a projection 950a at its longitudinal center. The projection 950a has the same shape as shown in Figure 10(b) of Embodiment 1. As shown in Figure 13, the projection 950a consists of a curved surface 950a1 coaxial with the axis of the rotating shaft 950 when viewed from the axial direction of the rotating shaft 950, and planes 950a2 and 950a3 inclined with respect to the axis of rotation when viewed from a direction perpendicular to the axis (direction of arrow d).

Figure 14 is a schematic perspective view of the container body 940. Figure 15 is an enlarged view of the longitudinal center of the container body 940, and Figure 16 is a schematic cross-sectional view of the toner transport section 920 as seen from the rotation axis direction of the stirring member 96, and is a cross-sectional view seen from the same direction as Figures 6 to 8 of Embodiment 1. As shown in Figures 12 to 16, in this embodiment, a gently protruding shape 940k (convex portion) is provided on the longitudinal portion of the inner wall 940h of the container body 940 that faces the protruding portion 950a. In this embodiment, the protruding shape 940k has a curved surface coaxial with the inner wall 940h, and its radius is denoted as r _k .

As described above, in Example 1, the radius of Rm - r _h is made larger than the clearance between the protruding portion 95a and the wall 94h. In other words,
(Rm radius - _{r h} ) > (r _h - _{r a} ) ... (1)
r _a > (radius of 2r _h - Rm) ... (2)
This configuration ensures that even if the rotating shaft 95 receives a reaction force from a part of the toner transport section 92 and bends due to creep deformation, the stirring member 96 will reliably contact the wall 94h at the desired phase.

In this embodiment, by providing the protruding shape 940k, when creep deformation as described in Embodiment 1 occurs, the protruding portion 950a comes into contact with the protruding shape 940k before coming into contact with the inner wall 940h, and is unable to deform any further. Therefore, in this embodiment, r _h can be replaced with r _k in equation (2).
r _a > (radius of 2r _k - Rm) ... (3)

Since the radius r _k of the protruding shape 940 k from the center O is smaller than the radius r _h of the inner wall 94 h, providing the protruding shape 940 k makes it possible to reduce the amount of protrusion of the protruding part 950 a, that is, the radius r _a of the protruding part 950 a.

As mentioned above, since toner melts above a certain temperature, it is preferable that the toner transport unit 920 is not configured in such a way that the toner is continuously rubbed against the minute gap between the rotating shaft 950 and the opposing member, thereby accumulating frictional heat.

As in this embodiment, by partially protruding the inner wall 940h, the amount of protrusion of the protruding portion 950a that contacts the inner wall 940h when the amount of deformation due to creep exceeds a certain amount can be reduced. This increases the clearance between the protruding portion 950a and the inner wall 940h other than the protruding shape 940k, and the surrounding internal components of the toner transport section 920 in the radial direction relative to the rotation axis of the rotating shaft 950, thereby preventing an increase in frictional heat.

Furthermore, in order to increase the clearance with the protruding portion 950a during rotation and reduce frictional heat, it is preferable that the range of the protruding shape 940k in the rotational direction be kept to the minimum necessary. In other words, only the portion of the toner transport section 920 that comes into contact with the protruding portion 950a during creep deformation needs to be made to protrude. Specifically, in the toner transport section 920, the stirring member 96 should be in contact with the inner wall 940i at locations where the distance from the rotating shaft 950 is close and creep deformation of the rotating shaft 950 is a concern. The stirring member 96 should then be in a direction that causes the rotating shaft 950 to bend due to the reaction force generated by this contact, that is, in a direction that pushes it approximately opposite to the free end of the stirring member 96.

Figures 19(a) and 19(b) show the rotation shaft 950 and the stirring member 96 when the stirring member 96 is in contact with the inner wall 940i. This is one of the phases in this embodiment where creep deformation is a concern. Figure 19(b) is a partially enlarged view of Figure 19(a). The restoring force of the rotation shaft 950 at this time acts between the direction normal to the extension direction (dashed line s) of the stirring member 96 in its undeformed state and the direction normal to the tangential line at the contact point (contact point) when the stirring member 96 contacts the inner wall 940i.

Therefore, the protruding shape 940k should be located within the following range. Specifically, a straight line v, passing through the center O of the rotation axis 950 and perpendicular to the extension direction of the undeformed stirring member 96 (dashed line s in Figure 19(b)), contacts the aforementioned contact portion of the stirring member 96 with the rotation trajectory Rm on the opposite side of the center point O of the rotation axis 950. Then, a straight line w, perpendicular to the tangent line at the contact point (dotted line t in Figure 19(b)) when the stirring member 96 is in contact, contacts the aforementioned contact portion of the stirring member 96 with the rotation trajectory Rm on the opposite side of the center point O of the rotation axis 950. With this setting, the protruding shape 940k should be located between line segment OG and line segment OFF in the rotation direction of the rotation axis 950.

In this embodiment, the phase in which creep deformation is a concern due to the close distance to the rotating shaft 950 is the entire phase in which the stirring member 96 contacts 940i. Therefore, it is preferable that the protruding shape 940k is within the above range in each of these phases. As a result, in this embodiment, the protruding shape 940k is provided as shown in Figure 19.

Furthermore, as shown in Figure 13, the protrusion 950a is configured to be inclined rather than perpendicular to the axial direction of the rotating shaft 950, and thus possesses a toner transport force in the axial direction. As the rotating shaft 950 rotates, the downstream side surface 950a2 of the protrusion 950a in the direction of rotation pushes away the surrounding toner, preventing the toner that has been rubbed between the protrusion 950a and the toner transport section 920 and generated frictional heat from being rubbed again. At this time, by making the direction in which the toner is pushed away and transported by the protrusion 950a the same as the direction of toner transport by the screw 98, it becomes possible to transport the toner towards the toner transport path 761 more efficiently.

Furthermore, as shown in Figures 14 and 15, the inner wall 940i has a surface 940j in the longitudinal direction, opposite to the protrusion 950a, which is angled away from the rotation axis 950 compared to 940i. This further ensures clearance between the protrusion 950a and the inner wall of the container body 940. On the other hand, as shown in Figure 14, since the surface 940j is located in a part of the central longitudinal section, the orientation of the stirring member 96 does not change significantly due to the influence of surface 940j.

In this embodiment, the shape of the protruding shape 940k is gently formed so that when the stirring member 96 passes over the protruding shape 940k during rotation, the free end of the stirring member 96 deforms longitudinally and conforms to the shape of the protruding shape 940k. This ensures that the tip of the stirring member 96 rotates without separating from the inner wall 940h and the protruding shape 940k, thus preventing a decrease in toner transport efficiency.

The shapes of the protruding shape 940k and the protruding portion 950a in this embodiment are not limited to the shapes described above. For example, the protruding shape 940k of this embodiment may be combined with the protruding portion 95a shown in Embodiment 1. Furthermore, the protruding shape 940k shown in Figure 17 does not have a gentle slope like the protruding shape 940k shown in Figure 14, and only the portion that contacts the protruding portion protrudes; however, this may be combined with the shapes of the protruding portions 95a and 950a.

Furthermore, the protruding portion shapes of each modified example shown in Figures 10(a) to 10(c) may also be adopted in this embodiment. Additionally, a configuration with multiple protruding portion shapes 940k may be adopted, corresponding to the multiple protruding portion configurations shown in Figures 11(a) and 11(b).

In this way, according to this embodiment, deformation of the rotating shaft can be suppressed in a stirring means equipped with a stirring member on the rotating shaft. This makes it possible to provide a toner transport device and an image forming apparatus that enable efficient toner stirring and transport, and that are less prone to toner solidification even in high-temperature environments.

The configurations of each embodiment and each modified example described above may be combined with each other, as long as no technical inconsistencies arise. In this embodiment, an example of a container configuration was described in which the inner surface forming the toner storage space in the toner container can have a sliding phase in which it slides with the stirring member and a non-sliding phase in which it does not slide. However, the container configuration to which the present invention can be applied is not limited to this. For example, the present invention is also suitably applicable to toner transport devices with a container inner surface configuration without a non-sliding phase, i.e., a container configuration in which the sliding member is always in contact with the inner surface of the container.

9...Cleaning device, 71...Intermediate transfer belt, 92...Toner transport section, 94...Container body, 95...Rotating shaft, 95a...Protruding part, 96...Agitation member, 97...Agitation means, 98...Screw

Claims (22)

A container capable of holding toner,
A rotating member rotatably provided inside the container and extending in the direction of the rotation axis, having a protruding portion that protrudes in a direction perpendicular to the direction of the rotation axis,
A flexible, sheet-like stirring member is provided on the outer circumference of the rotating member, with one end fixed to the rotating member, and the stirring member is capable of stirring the toner as the rotating member rotates.
Equipped with,
The stirring member comes into contact with the inner surface of the container and deforms as the rotating member rotates.
When the rotating member is viewed in a cross-section perpendicular to the axis of rotation, the rotational trajectory formed by the rotation of the rotating member, in which the free end of the stirring member is in contact with the inner surface of the container and is not deformed, has a radius equal to the line segment connecting the free end and the center of rotation of the rotating member.
If the phase in which the free end contacts the inner surface of the container and deforms is defined as the first phase, and the phase in which the free end does not contact the inner surface of the container is defined as the second phase,
When the rotational trajectory is divided into two by a first straight line parallel to the extension direction of the stirring member and passing through the center of rotation of the rotating member, and the free end is positioned in the first phase, the region on the opposite side of the first straight line from the first region where the free end is located is defined as the second region.
The aforementioned protrusion is
The rotating member is partially provided in the circumferential direction, and at least a portion of it is located in the second region where a second straight line perpendicular to the first straight line and passing through the center of rotation of the rotating member intersects the rotation trajectory in the direction of rotation of the rotating member,
In the first phase, when the stirring member is deformed, the second position is located in the second region when the third straight line, which is perpendicular to the tangent line passing through the point of contact formed between the inner surface of the container and the stirring member and passes through the center of rotation, is bisected by a third straight line, and the third straight line intersects the rotation trajectory.
It is placed between them ,
The container has a contact portion on its inner surface that comes into contact with the stirring member,
The toner transport device is characterized in that the protruding portion protrudes from the outer circumferential surface of the rotating member toward the inner surface of the container, is provided in a region substantially opposite to the contact portion on the outer circumference of the rotating member with respect to the axis of rotation, and is configured such that when the rotating member is stopped and the stirring member is in contact with the contact portion, the protruding portion contacts the inner surface separated from the contact portion, and while the rotating member is rotating, the protruding portion separates from the inner surface separated from the contact portion . The toner transport device according to claim 1, characterized in that the protruding portion includes a portion located in a region opposite to the side where the contact portion is located, with respect to a second imaginary line that is perpendicular to a first imaginary line passing through the contact portion and the rotation axis, in a cross- section perpendicular to the rotation axis. The toner transport device according to claim 2 , characterized in that the portion of the protruding part intersects with the first imaginary line. The toner transport device according to claim 2 or 3 , characterized in that the portion of the protruding part has an angle greater than 90 degrees between one end and the other end in the circumferential direction of the outer circumference of the rotating member and the angle made with respect to the axis of rotation. The toner transport device according to any one of claims 1 to 4, characterized in that the inner surface of the container has a shape that changes the distance between it and the axis of rotation in a direction perpendicular to the axis of rotation of the rotating member, so that the stirring member can take on a first phase and a second phase due to the rotation of the rotating member. The toner transport device according to any one of claims 1 to 5 , characterized in that the protrusion is provided at a position away from the end of the rotating member in the direction of the rotation axis. The toner transport device according to any one of claims 1 to 6 , characterized in that the protruding portion is provided approximately in the center of the rotating member in the direction of the rotation axis. The toner transport device according to any one of claims 1 to 7 , characterized in that a plurality of protrusions are provided at intervals in the direction of the rotation axis. The toner transport device according to any one of claims 1 to 8 , characterized in that the protrusion is provided on the outer circumferential surface of the rotating member so as to extend along the rotational direction of the rotating member. The toner transport device according to any one of claims 1 to 9 , characterized in that the protrusion is provided on the outer circumferential surface of the rotating member so as to extend in a direction inclined with respect to the rotational direction of the rotating member. The toner transport device according to any one of claims 1 to 9 , characterized in that the protrusion is provided on the outer circumferential surface of the rotating member so as to extend helically with respect to the axis of rotation. The toner transport device according to claim 10 or 11 , characterized in that the side surface of the protruding portion is a curved surface that forms part of a screw having transport properties for transporting toner in the direction of the rotation axis. The toner transport device according to claim 10 or 11 , characterized in that the side surface of the protruding portion is composed of a surface extending in a direction inclined with respect to the direction of the rotation axis and a direction perpendicular to the rotation axis. The container further comprises a transport member that transports toner in a first direction parallel to the axis of rotation inside the container,
The rotating member rotates counterclockwise around the axis of rotation when viewed in the second direction, which is the opposite direction to the first direction.
The toner transport device according to any one of claims 10 to 13, characterized in that the protruding portion is inclined such that its position in the rotational direction changes from the upstream side to the downstream side as it moves toward the second direction. The toner transport device according to any one of claims 1 to 14, characterized in that the protruding portion has a plurality of convex portions arranged in the extending direction such that a plurality of peaks in the protruding height are formed in the direction extending on the outer circumferential surface of the rotating member . The inner surface of the container has a convex portion that protrudes toward the axis of rotation at a position corresponding to the protrusion in the direction of the axis of rotation,
The toner transport device according to any one of claims 1 to 15 , characterized in that the convex portion faces the protruding portion when the stirring member is in contact with the contact portion. In a cross-section perpendicular to the axis of rotation,
Let Rm be the radial distance from the axis of rotation to the free end, when the stirring member is not deformed by an external force applied to the free end.
When the stirring member is in contact with the contact portion, the radial distance from the axis of rotation to the position where the stirring member contacts the inner surface of the stirring member is denoted as r _h .
When the radial distance from the axis of rotation to the tip of the protrusion is denoted as r _a ,
(Rm-r _h )>(r _h -r _a )...(1)
r _a > (2r _h - Rm)...(2)
A toner transport device according to any one of claims 1 to 16 , characterized in that it satisfies the following conditions. An image forming unit including an image carrier that holds a toner image, and a transfer means for transferring the toner image from the image carrier to a transfer target,
A cleaning means for removing toner from the image carrier,
A toner recovery device that recovers the toner removed from the image carrier by the cleaning means,
In an image forming apparatus comprising,
The image forming apparatus is characterized in that the toner recovery device comprises a toner transport device according to any one of claims 1 to 17 . The toner recovery device includes a recovery container for containing the toner removed from the image carrier by the cleaning means.
The image forming apparatus according to claim 18 , characterized in that the toner transport device transports the toner removed by the cleaning means from the image carrier to the collection container. The image forming apparatus according to claim 18 or 19 , characterized in that the toner transport device is arranged near a heat source in the image forming apparatus. The device includes a fixing device that heats the toner image transferred to the recording material, which is the transfer target, to fix it to the recording material,
The image forming apparatus according to any one of claims 18 to 20 , characterized in that the toner transport device is arranged in the vicinity of the fixing device. The image forming apparatus according to any one of claims 18 to 21 , characterized in that the image carrier is an intermediate transfer belt.