JP2024043124A - Developing device and image forming apparatus including the same - Google Patents

Abstract

To provide a developing device and an image forming apparatus that can reduce retention of developer near a paddle roller, and thereby can prevent the occurrence of streak-like unevenness on an image to be formed.SOLUTION: A developing device 2 comprises: a developer tank 21 that stores developer D; a developer carrier 24 that carries the developer D stored in the developer tank 21; and a paddle roller 23 that is provided in a circumferential direction S with a plurality of blades 231(1)-231(n) projecting in projection directions V-V orthogonal to an axial direction E along a rotation axis α1 and extending in the axial direction E, and the developing device sends out the developer D stored in the developer tank 21 toward the developer carrier 24 using the plurality of blades 231(1)-231(n) provided on the paddle roller 23. The plurality of blades 231(1)-231(n) on the paddle roller 23 are respectively provided with a plurality of notch parts 23a in the axial direction E at tip parts in the projection directions V-V.SELECTED DRAWING: Figure 6C

Description

The present disclosure relates to a developing device and an image forming apparatus including the same, such as a copying machine, a multifunction device, a printer, and a facsimile machine.

As a conventional developing device, a paddle roller is provided with a plurality of blades in the circumferential direction that protrude in a protruding direction perpendicular to the axial direction along the rotation axis and extend in the axial direction. There is one that is configured to send the developer contained in a tank toward a developer carrier (see Patent Document 1).

Japanese Patent Application Publication No. 2002-182459

In such a developing device, developer may accumulate near the paddle roller. This will be explained below using a conventional developing device as an example with reference to FIGS. 12 and 13.

FIG. 12 is a sectional view showing a schematic configuration of a conventional developing device 2X. FIG. 13 is a perspective view showing a conventional paddle roller 23X.

As shown in FIG. 12, the developing device 2X includes a developing tank 21 that contains developer D, an agitating member 22 (agitation roller) that agitates the developer D contained in the developing tank 21, a paddle roller 23X that has multiple blades 231X(1) to 231X(n) (n is an integer of 2 or more, n=8 in this example) evenly spaced in the circumferential direction S, and a developer carrier 24 that carries the developer D.

In this example, the stirring member 22 is disposed below the developer carrier 24. The paddle roller 23X is located between the stirring member 22 and the developer carrier 24 so that the rotational axis α1 is located below the virtual straight line β connecting the rotational axis α2 of the stirring member 22 and the rotational axis α3 of the developer carrier 24. It is arranged so that The paddle roller 23X is rotated in a first rotation direction R1 (counterclockwise in the illustrated example). The blades 231X(1) to 231X(n) in the paddle roller 23X protrude in protruding directions V to V perpendicular to the rotational axis α1 (the axial direction E of the rotational axis α1 along), and protrude in the axial direction E of the rotational axis α1. (See Figure 13).

As shown in FIG. 12, in the developing device 2X, the developer D is stirred in the developer tank 21 by the stirring member 22 that is rotated in the second rotation direction R2 (clockwise in the illustrated example). is sent out (sumpped up and conveyed) by the paddle roller 23X, which is rotated in the first rotational direction R1, toward the developer carrier 24, which is rotated in the first rotational direction R1. The developer D delivered to the developer carrier 24 transfers to the surface 3a of the photoreceptor drum 3 rotated in the second rotation direction R2, and the electrostatic latent image formed on the surface 3a of the photoreceptor drum 3 is transferred to the surface 3a of the photoreceptor drum 3. Develop. The developer D after development is moved by the paddle roller 23X between the paddle roller 23X and the lower wall 21a of the developer tank 21, and is returned to the stirring member 22 side, and the above-described series of developing operations is repeated.

At this time, if the transportability of developer D from developer carrier 24 to agitator 22 by paddle roller 23X is reduced, developer D is not sufficiently peeled off from developer carrier 24 due to insufficient transport force of paddle roller 23X, and developer D peeled off from developer carrier 24 is difficult to transport in space SP surrounding developer carrier 24, bottom wall 21a of developer tank 21, and paddle roller 23X, and developer D accumulates near paddle roller 23X, resulting in accumulation G of developer D. When this happens, accumulation G prevents paddle roller 23X from sending developer D to developer carrier 24 (pumping and transporting), which causes streaks in the formed image.

Therefore, the present disclosure aims to provide a developing device and an image forming device that can reduce the accumulation of developer near the paddle roller, thereby suppressing the occurrence of streaks in the formed image.

In order to solve the above problems, a developing device according to the present disclosure includes a developer tank that stores a developer, a developer carrier that supports the developer stored in the developer tank, and an axis along a rotation axis. a paddle roller provided with a plurality of blades in the circumferential direction that protrude in a protruding direction perpendicular to the projecting direction and extend in the axial direction; A developing device that sends developer toward the developer carrier, wherein a plurality of notches are provided in the axial direction at the tip of the plurality of blades of the paddle roller in the protruding direction. It is characterized by

Further, an image forming apparatus according to the present disclosure is characterized in that it includes the developing device according to the present disclosure.

According to the present disclosure, retention of developer near the paddle roller can be reduced, and thereby it is possible to suppress the occurrence of streaks in the formed image.

FIG. 1 is a schematic cross-sectional view of the image forming apparatus according to the present embodiment viewed from the front. 2 is a cross-sectional view showing a developing device portion of the image forming apparatus shown in FIG. 1 . 2 is a perspective view including a cross section of a developing device portion of the image forming apparatus shown in FIG. 1. FIG. FIG. 2 is an enlarged perspective view showing a front side portion of the paddle roller according to the first embodiment. FIG. 2 is a front view of the paddle roller and an exploded side view of the blades of the paddle roller according to the first embodiment. FIG. 3 is a perspective view showing the front side of a paddle roller portion in a state where stirring is stopped in the developing device according to the first embodiment. FIG. 3 is a perspective view showing the front side of a paddle roller portion in a stirring start state in the developing device according to the first embodiment. FIG. 3 is a perspective view showing the front side of a paddle roller portion in an agitating operation state in the developing device according to the first embodiment. They are a front view of a paddle roller according to a second embodiment, and a side view showing an exploded view of blades in the paddle roller. It is a perspective view which expands and shows the front side of the paddle roller part based on 3rd Embodiment. It is a front view and a top view which expand and show the front side of the paddle roller part concerning a 3rd embodiment. FIG. 3 is an enlarged front view showing a paddle roller portion of the developer tank to which a paddle roller is attached. FIG. 3 is a perspective view showing a state before the paddle roller is attached to the developer tank. FIG. 3 is a perspective view showing a state in which the paddle roller is in the middle of the developer tank. FIG. 3 is a perspective view showing a state after the paddle roller is attached to the developer tank. 1 is a cross-sectional view showing a schematic configuration of a conventional developing device. FIG. 2 is a perspective view showing a conventional paddle roller.

Embodiments according to the present disclosure will be described below with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[Image forming device]
FIG. 1 is a schematic cross-sectional view of an image forming apparatus 100 according to the present embodiment viewed from the front. In the figure, the symbol X represents the left-right direction when viewed from the front of the image forming apparatus 100, and the symbols X1 and X2 represent the left side (one side) and the right side (the other side), respectively. The symbol Y represents the depth direction (front-back direction) orthogonal to the left-right direction X, and the symbols Y1 and Y2 represent the front side (one side, operation side) and the back side (the other side), respectively. The symbol Z represents the up-down direction (vertical direction).

Image forming apparatus 100 according to the present embodiment is a monochrome image forming apparatus for recording sheet P such as paper. The image forming apparatus 100 performs image forming processing according to image data read by the image reading apparatus 90 or image data transmitted from the outside. Note that the image forming apparatus 100 may be a monochrome image forming apparatus of another type. Further, the image forming apparatus 100 may be a color image forming apparatus that forms multicolor and monochrome images.

The image forming apparatus 100 includes an image reading device 90 and an image forming apparatus main body 101. The image forming apparatus main body 101 includes an image forming section 102 and a sheet conveying system 103.

The image reading device 90 is provided at the top of the image forming apparatus main body 101. The image reading device 90 reads an image of a document (not shown), and includes a document conveying section 90a and a document reading section 90b. The image reading device 90 reads the image of the document with the document reading section 90b while conveying the document in the document conveying section 90a, or reads the document placed on the document table of the document reading section 90b. Scan and read. The image of the document read by the image reading device 90 is sent to the image forming apparatus main body 101 as image data.

The image forming section 102 includes an exposure device 1 (exposure unit), a development device 2 (development unit), a photosensitive drum 3 that acts as an image carrier, a cleaning device 4 (cleaning unit), a charging device 5, a transfer device 6 (transfer (belt device), a fixing device 7 (fixing unit), and a toner cartridge 8. Further, the sheet conveyance system 103 includes a paper feed tray 9, a discharge roller 10, and a discharge tray 11.

The transfer device 6 transfers the toner image formed on the photoreceptor drum 3 onto the recording sheet P fed from the paper feed tray 9. The cleaning device 4 removes toner (waste toner) remaining on the photosensitive drum 3 without being transferred to the recording sheet P by the transfer device 6.

The image forming apparatus main body 101 is provided with a sheet conveyance path W1. The sheet supply unit 12 supplies the recording sheet P accommodated in the paper feed tray 9 to the sheet conveyance path W1. The sheet conveyance path W1 guides the recording sheet P to the discharge tray 11 via the transfer member 6a of the transfer device 6 (transfer belt in this example), the fixing device 7, and the discharge roller 10. The fixing device 7 heats and fixes the toner image formed on the recording sheet P by the transfer device 6 onto the recording sheet P. A sheet supply section 12, a plurality of conveyance rollers 13 to 13, a registration roller 14, a transfer device 6, a fixing roller 71 and a pressure roller 72 in a fixing device 7, and a discharge roller 10 are arranged near the sheet conveyance path W1. ing.

In the image forming apparatus 100, the recording sheet P supplied from the paper feed tray 9 to the sheet conveyance path W1 by the sheet supply section 12 is conveyed to the registration rollers 14 via conveyance rollers 13 to 13. Next, the recording sheet P is conveyed by the registration rollers 14 to the transfer member 6a of the transfer device 6 at a timing to align the recording sheet P and the toner image on the photoreceptor drum 3, and the transfer device 6 transfers the toner image onto the recording sheet P. transferred on top. Thereafter, the recording sheet P passes through a fixing roller 71 and a pressure roller 72 in the fixing device 7, passes through a conveyance roller 13 and an ejection roller 10, and is ejected onto an ejection tray 11. When forming an image not only on the front side but also on the back side of the recording sheet P, the recording sheet P is conveyed in the opposite direction from the discharge roller 10 to the reversing sheet conveyance path W2. The recording sheet P passes through the reversing conveyance rollers 15 to 15, reverses the front and back sides of the recording sheet P, and is led to the registration rollers 14 again. Then, the recording sheet P is discharged toward the discharge tray 11 after a toner image is formed and fixed on the back surface in the same manner as on the front surface.

In this example, the developing device 2 develops the electrostatic latent image on the photoreceptor drum 3 with a two-component developer (developer) containing toner and carrier as main components. The developing device 2 supplies non-magnetic toner contained in the two-component developer onto the surface 3a of the photosensitive drum 3 by a developing electric field formed between the developing device 2 and the photosensitive drum 3.

[Developing device]
Fig. 2 is a cross-sectional view showing the developing device 2 portion of the image forming apparatus 100 shown in Fig. 1. Fig. 3 is a perspective view including a cross section of the developing device 2 portion of the image forming apparatus 100 shown in Fig. 1. Fig. 4 is an enlarged perspective view showing a front side portion of the paddle roller 23 according to the first embodiment. Fig. 5 is a front view of the paddle roller 23 according to the first embodiment and a side view showing the blades 231(1) to 231(n) of the paddle roller 23 in an exploded view.

The developing device 2 includes a developing tank 21 containing a developer containing toner and carrier. The developer tank 21 extends in the longitudinal direction (depth direction Y), and the developer tank 21 is provided with an opening at a position facing the photoreceptor drum 3 .

The developing device 2 includes a developing tank 21 that contains developer D, an agitating member 22 (agitation roller) that agitates the developer D contained in the developing tank 21, an agitation conveying member 25 (agitation conveying roller), a paddle roller 23 with multiple blades 231(1) to 231(n) (n is an integer of 2 or more, n=4 in this example) evenly arranged in the circumferential direction S, and a developer carrier 24 that carries the developer D.

In this example, the stirring member 22 is disposed below the developer carrier 24. In this example, the paddle roller 23 includes a blade portion 232 and a rotating shaft 233. The blade portion 232 is composed of a plurality of blades 231(1) to 231(n) and a cylindrical portion 232a to which the plurality of blades 231(1) to 231(n) are fixed evenly in the circumferential direction S. , the cylindrical portion 232a is fitted onto the rotating shaft 233. The plurality of blades 231(1) to 231(n) constituting the paddle roller 23 and the cylindrical portion 232a are integrally formed.

The paddle roller 23 has its rotational axis α1 located below the rotational axis α3 of the developer carrier 24, specifically, between the stirring member 22 and the developer carrier 24, the rotational axis α1 is located below the rotational axis α2 of the stirring member 22. and the rotational axis α3 of the developer carrier 24. The blades 231(1) to 231(n) of the paddle roller 23 protrude in protruding directions V to V orthogonal to the axial direction E along the rotational axis α1 and extend in the axial direction E.

Specifically, the developer carrier 24 is a magnetic roller, and is arranged along an opening provided in the developer tank 21 at a position facing the photoreceptor drum 3 . The developer carrier 24 includes a sleeve portion (not shown) formed in a non-magnetic cylindrical shape and rotatable around the rotational axis α3, and a cylindrical, magnetic and rotatable sleeve portion disposed inside the sleeve portion. It is equipped with a mag roll part that does not work. A plurality of magnetic poles each having a single polarity are formed on the circumferential surface of the developer carrier 24 due to the magnetism of the mag roll portion. The developer carrier 24 is supported by the developer tank 21 at a position facing the photoreceptor drum 3 so as to be spaced from the photoreceptor drum 3 by a predetermined distance. The developer carrier 24 supports the developer D contained in the developer tank 21 on its surface, and the sleeve portion rotates in the first rotation direction R1 (centering on the rotation axis α3 arranged along the longitudinal direction (Y)) It is configured to rotate in a clockwise direction (in FIG. 2).

The developer D supported on the surface of the developer carrier 24 is regulated to a predetermined thickness by a regulating blade 212 provided in the developer tank 21, and is rotated in the second rotation direction R2 (inverted in FIG. 2) about the rotation axis α4. The photoreceptor drum 3 is conveyed to the surface 3a of the photoreceptor drum 3, which is rotated in a clockwise direction. In the development region where the photoreceptor drum 3 and the developer carrier 24 face each other, the electrostatic latent image formed on the surface 3a of the photoreceptor drum 3 is developed by the toner in the developer D.

The developer tank 21 is provided with a first chamber 21c and a second chamber 21d. The first chamber 21c and the second chamber 21d are provided on one side X1 and the other side X2 of the developer tank 21 in the left-right direction X, respectively, and accommodate the developer D. The first chamber 21c and the second chamber 21d form a long space along the longitudinal direction (Y) (axial direction E). The second chamber 21d is provided above the first chamber 21c on the photosensitive drum 3 side. The first chamber 21c is provided with an agitation conveyance member 25 on the toner supply side and an agitation member 22 closer to the photoreceptor drum 3 than the agitation conveyance member 25. A paddle roller 23 and a developer carrier 24 closer to the photosensitive drum 3 than the paddle roller 23 are arranged in the second chamber 21d. The developer tank 21 is provided with a lower wall 21a that is inclined with respect to the vertical direction Z between the paddle roller 23 and the photoreceptor drum 3.

In the first chamber 21c, the agitation conveyance member 25 agitates the developer D at a location where the toner from the toner cartridge 8 is replenished through the toner replenishment port 21e of the developer tank 21. The stirring conveyance member 25 rotates in the first rotation direction R1 about the rotation axis α5. Thereby, the stirring conveyance member 25 can move the developer D to the stirring member 22 while stirring the developer D. The stirring member 22 on the photosensitive drum 3 side, in other words, the paddle roller 23 side of the stirring conveyance member 25 on the toner supply side stirs the developer D from the stirring conveyance member 25 . The stirring member 22 rotates in the second rotation direction R2 about the rotation axis α2. Thereby, the stirring member 22 can move the developer D to the paddle roller 23 in the second chamber 21d while stirring the developer D.

In the second chamber 21d, the paddle roller 23 stirs the developer D from the stirring member 22. The paddle roller 23 rotates in a first rotation direction R1 about the rotation axis α1. Thereby, the paddle roller 23 can feed (pump up and convey) the developer D to the developer carrier 24 while stirring the developer D.

(First embodiment)
6A to 6C are perspective views showing the front side of the paddle roller 23 portion in the agitation stop state, agitation start state, and agitation operation state in the developing device 2 according to the first embodiment, respectively.

As shown in Figures 4 to 6C, a plurality of notches 23a are provided in the axial direction E at the tips of the blades 231(1) to 231(n) of the paddle roller 23 in the protruding direction V.

In the developing device 2 according to the present embodiment, the developer D is stirred in the developer tank 21 by the stirring member 22 rotated in the second rotation direction R2, and the stirred developer D is rotated in the first rotation direction R1. The developer carrier 24 (see FIG. 2) is rotated in the first rotation direction R1 by the paddle roller 23 that rotates the developer. The developer D sent to the developer carrier 24 moves to the surface 3a of the photoreceptor drum 3 (see FIGS. 2 and 3), which is rotated in the second rotation direction R2, and is deposited on the surface 3a of the photoreceptor drum 3. Develop the electrostatic latent image formed on the surface. The developer D after development is moved by the paddle roller 23 between the paddle roller 23 and the lower wall 21a of the developer tank 21, and is returned to the stirring member 22 side, and the above-described series of developing operations is repeated.

At this time, the surface pressure acting on the developer D present in the area corresponding to the notches 23a-23a of the paddle roller 23 rotating in the first rotation direction R1 is lower than the surface pressure acting on the developer D present in the area corresponding to the blade portion where the notches 23a-23a are not provided, so the developer D that passes through the notches 23a-23a due to the rotation of the paddle roller 23 is blown out in the blowing direction F-F (see FIG. 6C) and moves to both sides in the axial direction E. In this way, the rotation of the paddle roller 23 can apply a shear force to the developer D passing through the notches 23a-23a provided in the blades 231(1)-231(n) of the paddle roller 23, and therefore, a stirring force in the axial direction E can be applied to the developer D that passes through the notches 23a-23a at the tip end in the protruding direction V-V of the blades 231(1)-231(n).

That is, by providing multiple notches 23a-23a in the axial direction E, multiple regions in the axial direction E where the stirring force in the axial direction E acts can be provided. This allows the developer D puddle G (see FIG. 12) peeled off from the developer carrier 24 to be effectively broken down. This makes it possible to suppress the developer D from accumulating, and the developer D can be smoothly transported downstream in the first rotation direction R1 by the paddle roller 23. In this example, the developer D puddle G (see FIG. 12) peeled off from the developer carrier 24 in the space SP surrounding the developer carrier 24, the lower wall 21a of the developer tank 21, and the paddle roller 23 can be effectively broken down, reducing the accumulation of the developer D near the paddle roller 23, and sequentially transporting the developer D to the stirring member 22 side.

As described above, according to the present embodiment, a plurality of notches 23a are provided in the axial direction E at the tips of the plurality of blades 231(1) to 231(n) of the paddle roller 23 in the protruding directions V to V. Therefore, it is possible to reduce the retention G of the developer D near the paddle roller 23 (see FIG. 12), and thereby it is possible to suppress the occurrence of streaks in the formed image.

In this embodiment, as shown in FIG. 5, the notches 23a to 23a are adjacent blades [231(1), 231(2)], [231(2), 231(3)] in the circumferential direction S. , ..., [231(n), 231(1)] are provided at different positions in the axial direction E.

By doing so, the position (in the axial direction E) of the developer D that is cut off by the notches 23a to 23a can be sequentially changed by the rotation of the paddle roller 23. Thereby, the accumulation of the developer D can be effectively broken up, and the developer D can be further smoothly conveyed toward the downstream side in the first rotation direction R1 in the paddle roller 23.

In the present embodiment, in the individual blades 231(1) to 231(n), the widths d(1) to d(n) (see FIG. 5) in the axial direction E of the notch 23a are the widths of the notches 23a in the axial direction E. It is smaller than the intervals w(1) to w(n) (see FIG. 5) between (23a, 23a), . . . , (23a, 23a). In this example, the widths d(1) to d(n) are all equal, and the intervals w(1) to w(n) are all equal.

By doing so, the agitation performance of the developer D can be improved without degrading the transport performance of the developer D by the paddle roller 23 as much as possible.

In this example, the shapes of the notches 23a to 23a are rectangular. However, the shape of the notches 23a to 23a is not limited to a rectangular shape.

(Second embodiment)
FIG. 7 is a front view of the paddle roller 23 according to the second embodiment and an exploded side view showing the blades 231(1) to 231(n) in the paddle roller 23.

In this embodiment, each of the notches 23a to 23a has a different depth k between one end and the other end in the axial direction E. Specifically, the depth k of each of the notches 23a to 23a becomes shallower in the axial direction E from the center toward both outer sides. In this case, the shapes of the notches 23a to 23a include, for example, a curved shape, an arc shape, a semicircular shape, a semielliptical shape, a U-shape, a V-shape, and the like. In FIG. 7, it has a semicircular shape.

In this way, by varying the depth k of the notches 23a-23a in the protruding directions V-V in the axial direction E, the widths d(1)-d(n) of the notches 23a-23a in the axial direction E can be configured to be wider toward the tip in the protruding directions V-V. In other words, the amount of developer D that slips through the notches 23a-23a can be increased toward the tip in the protruding directions V-V, and the amount of developer D that slips through the notches 23a-23a can be decreased toward the rotation axis α1 side. This makes it possible to change the amount of developer D that slips through the blades 231(1)-231(n) in the protruding directions V-V, and as a result, the stirring force for the developer D in the protruding directions V-V can be changed. This makes it possible to effectively break down the developer D that has accumulated on the developer carrier 24 side and transport it more smoothly to the stirring member 22 side.

For example, the shape and number of the notches 23a to 23a are changed, and/or in the case where the notches 23a to 23a are U-shaped or V-shaped, the opening angle of the U-shape or V-shape is sharpened or blunted. Thus, the shearing force and conveying force for the developer D can be adjusted according to the shape of the developer tank 21 and the characteristics of the developer D.

(Third embodiment)
FIG. 8 is an enlarged perspective view showing the front side of the paddle roller 23 portion according to the third embodiment. FIG. 9 is an enlarged front view and a plan view showing the front side of the paddle roller 23 portion according to the third embodiment. Note that in FIG. 9, the side plate 211 is shown in cross section, and the state in which the paddle roller 23 is being attached to the developer tank 21 is shown.

In the third embodiment, the number n of the blades 231(1) to 231(n) is eight, and the cutouts 23a to 23a are formed along a virtual spiral γ centered on the rotation axis α1. This is similar to the first embodiment and the second embodiment. Note that the shape of the notches 23a to 23a is rectangular.

In the third embodiment, the same components as those in the first and second embodiments are given the same reference numerals, and the description thereof is omitted.

In this embodiment, the notches 23a to 23a are adjacent blades [231(1), 231(2)], [231(2), 231(3)], ..., [231(n)] in the circumferential direction S. ), 231(1)] partially overlap each other in the axial direction E.

By doing this, it is possible to partially overlap the notches 23a and 23a in the axial direction E that are adjacent to each other in the circumferential direction S, thereby reducing the agitation force in the axial direction E by the notches 23a to 23a to the developer. D can be applied continuously in the axial direction E.

Figure 10 is an enlarged front view of the paddle roller 23 portion of the developing tank 21 to which the paddle roller 23 is attached. Figures 11A to 11C are perspective views showing the state before, during, and after the paddle roller 23 is attached to the developing tank 21, respectively.

Through holes 211a, 211a penetrating in the axial direction E are provided in the side plates 211, 211 on both sides of the developer tank 21 in the axial direction E, respectively. The side plates 211, 211 extend along a direction (left-right direction X) orthogonal to the rotation axis α2 of the developer carrier 24.

By the way, when attaching the paddle roller 23 to the developer tank 21 by inserting the paddle roller 23 from the outside of the through hole 211a on one side Y1 (front side in this example) without using the notches 23a to 23a, a plurality of blades It is necessary to make the diameter φ3 of the rotation trajectory of 231(1) to 231(n) (outer diameter of the paddle roller 23) (see FIG. 10) smaller than the diameter φ2 of the through hole 211a (see FIG. 10). In this case, as the diameter φ3 of the blades 231(1) to 231(n) is reduced, the conveyance of the developer D is reduced. From the viewpoint of improving the transportability of the developer D, it is possible to increase the diameter φ2 of the through hole 211a, but in this case, from the viewpoint of reducing the strength of the developer tank 21, the diameter φ2 of the through hole 211a may be increased. There are limits to what you can do.

In this embodiment, the paddle roller 23 is attached to the developing tank 21 by inserting the paddle roller 23 from the outside of the through hole 211a on one side Y1 (the front side in this example) using the notches 23a-23a. That is, the notches 23a-23a in the multiple blades 231(1)-231(n) are formed along a virtual spiral γ centered on the rotation axis α1. In detail, as shown in FIG. 9, in each blade 231(1)-231(n), the widths d(1)-d(1), ..., d(n)-d(n) of the notches 23a-23a in the axial direction E are all equal, and the intervals w(1)-w(1), ..., w(n)-w(n) between the notches 23a, 23a in the axial direction E are all equal. The cutouts 23a-23a are offset in the axial direction E between adjacent blades [231(1), 231(2)], [231(2), 231(3)], ..., [231(n), 231(1)] by a predetermined pitch T-T. The pitch T-T is smaller than the width d(1)-d(1), ..., d(n)-d(n) of the cutouts 23a-23a in the axial direction E.

As shown in FIG. 10, in the paddle roller 23, the diameter φ1 of the rotation locus of the bottom 23a1 of the notch 23a in the plurality of blades 231(1) to 231(n) is smaller than the diameter φ2 of the through hole 211a, and The diameter φ3 of the rotation trajectory of the plurality of blades 231(1) to 231(n) is larger than the diameter φ2 (FIG. 10) of the through hole 211a (φ1<φ2<φ3).

Specifically, as shown in FIG. 9, the paddle roller 23 has respective widths e(1) to e(1), . e(n) to e(n) are larger than the thickness h of the side plate 211 (the side plate through which the paddle roller 23 is inserted) provided with the through hole 211a. In this example, both side walls 23a2, 23a2 of the notches 23a to 23a in the helical orthogonal direction H are along the helical direction M.

In addition, the paddle roller 23 has a diameter φa1 in the spiral direction M of the rotation trajectory of the bottom 23a1 of the notch 23a of the multiple blades 231(1) to 231(n) that is smaller than the diameter φ2 of the through hole 211a, and a diameter φa3 in the spiral direction M of the rotation trajectory of the multiple blades 231(1) to 231(n) that is larger than the diameter φ2 of the through hole 211a (φa1<φ2<φa3).

In the paddle roller 23 described above, when attaching it to the developer tank 21 (see FIG. 11A), the paddle roller 23 is moved in the first rotation direction R1 while engaging the notches 23a to 23a along the virtual spiral γ into the through hole 211a. Rotate (see Figure 11B). Then, the paddle roller 23 moves to the other side Y2 (back side in this example) in the depth direction Y while rotating in a predetermined rotation direction (first rotation direction R1 in this example), and is housed in the developer tank 21 (see FIG. 11C).

As described above, in the paddle roller 23 according to the present embodiment, when the paddle roller 23 is attached to the developer tank 21 by inserting the paddle roller 23 from the outside of the through hole 211a on one side Y1 (front side in this example). , while rotating the paddle roller 23 in a predetermined rotational direction (R1), it can be moved to the other side Y2 in the depth direction Y and housed in the developer tank 21. Therefore, even if the diameter φ2 of the through hole 211a is maintained considering the strength of the developer tank 21, the diameter φ3 (φa3) of the blades 231(1) to 231(n) can be increased. Transportability can be improved. Therefore, while applying the agitation force by the notches 23a to 23a to the developer D, it is possible to simultaneously improve the transportability of the developer D and the strength of the developer tank 21.

Note that when inserting the paddle roller 23 through one of the through holes 211a, in this example, the rotational axis α1 of the paddle roller 23 is made oblique to the rotational axis α2 of the developer carrier 24, and the paddle is inserted from the inside of the developer tank 21. The roller 23 is inserted into the developer tank 21 (see FIG. 9), switched back, and then installed so that it fits inside the developer tank 21. In addition, the part of the side plate 211 through which the paddle roller 23 is inserted (the part near the through hole 211a) It may be configured to be inclined with respect to the side plate 211. Alternatively, the rotational axis α1 of the paddle roller 23 may be aligned with the rotational axis α2 of the developer carrier 24, so that the part of the side plate 211 through which the paddle roller 23 is inserted (the part near the through hole 211a) is inclined with respect to the side plate 211. It may be configured as follows. By doing so, even when the pitches T to T of the notches 23a to 23a are widened, the paddle roller 23 can be inserted through the through hole 211a and reliably attached to the developer tank 21.

The present disclosure is not limited to the embodiments described above, and can be implemented in various other forms. Therefore, such embodiments are merely illustrative in all respects, and should not be interpreted in a limiting manner. The scope of the present disclosure is indicated by the claims, and is not restricted in any way by the main text of the specification. Furthermore, all modifications and changes that come within the scope of equivalents of the claims are intended to be within the scope of the present disclosure.

100 Image forming apparatus 2 Developing device 21 Developer tank 211 Side plate 211a Through hole 21a Lower wall 22 Stirring member 23 Paddle roller 231 Blade 232 Blade portion 233 Rotating shaft 23a Notch 23a1 Bottom portion 23a2 Both side walls 24 Developer carrier 25 Stirring conveyance member 3 Photosensitive drum (an example of an image carrier)
3a Surface D Developer E Axial direction F Blowout direction G Retention H Helical orthogonal direction M Helical direction P Recording sheet R1 First rotation direction R2 Second rotation direction S Circumferential direction SP Space T Pitch V Projection direction X Lateral direction Y Depth direction Z Vertical direction d Width e Width h Thickness k Depth w Interval α1 Rotation axis α2 Rotation axis α3 Rotation axis α4 Rotation axis α5 Rotation axis β Virtual straight line γ Virtual spiral φ1 Diameter φ2 Diameter φ3 Diameter φa1 Diameter φa3 Diameter

Claims (7)

A developer tank that accommodates a developer, a developer carrier that supports the developer stored in the developer tank, and a blade that protrudes in a protruding direction perpendicular to an axial direction along a rotational axis and extends in the axial direction. The developing device includes a plurality of paddle rollers provided in a circumferential direction, and sends out the developer contained in the developer tank toward the developer carrier by the plurality of blades provided on the paddle roller. hand,
A developing device characterized in that a plurality of notches are provided in the axial direction at the tip portions of the plurality of blades of the paddle roller in the protrusion direction. The developing device according to claim 1,
The developing device is characterized in that the cutout portions are provided at different positions in the axial direction between the adjacent blades in the circumferential direction. The developing device according to claim 1,
A developing device characterized in that, in each of the blades, a width of the notch in the axial direction is smaller than an interval between the notches in the axial direction. The developing device according to claim 1,
The developing device, wherein each of the notches has a different depth between one end and the other end in the axial direction. The developing device according to claim 1,
The developing device is characterized in that the cutout portions partially overlap each other in the axial direction between the blades adjacent in the circumferential direction. 2. The developing device according to claim 1,
a through hole penetrating in the rotation axis direction is provided in each of the two side plates of the developing tank in the axial direction,
the notches in the plurality of blades are formed along an imaginary spiral centered on the rotation axis,
The paddle roller is characterized in that each width of the notch in a direction perpendicular to the helical direction of the virtual spiral is greater than a thickness of the side plate in which the through hole is provided, the diameter of the rotation locus of the bottom of the notch of the multiple blades in the helical direction is smaller than the diameter of the through hole, and the diameter of the rotation locus of the multiple blades in the helical direction is greater than the diameter of the through hole. An image forming apparatus comprising the developing device according to any one of claims 1 to 6.

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