JP2023096631A - Conveying screw, powder conveying device, and image forming apparatus - Google Patents

Abstract

A conveying screw, a powder conveying apparatus, and an image forming apparatus capable of suppressing aggregation of powder are provided. A conveying screw such as a nozzle conveying screw 164 includes a shaft portion 164a and a main blade portion 164b such as a blade portion spirally wound around the shaft portion 164a. A drop-off preventing portion 164d is formed as a stepped portion rising one step from the outer peripheral surface of the shaft portion 164a in a direction away from the center of the shaft portion 164a at the downstream end portion in the toner conveying direction, which is one end portion of the blade portion. The drop-off preventing portion 164d is formed outside a region Z from one end of the main blade portion 164b to a position a predetermined distance downstream in the rotational direction of the conveying screw in the circumferential direction. [Selection drawing] Fig. 7

Description

The present invention relates to a conveying screw, a powder conveying device, and an image forming apparatus.

2. Description of the Related Art Conventionally, there has been known a conveying screw that includes a shaft portion and blade portions spirally wound around the shaft portion and that conveys powder.

In Patent Document 1, as the conveying screw, an eccentric screw is provided in which a swinging member that swings in vertical conveying is hooked on the shaft portion of the connecting portion with the vertical conveying path on the downstream side of the conveying direction of the powder by the blade portion. It is described with an eccentric portion. A part of this eccentric portion is eccentric so as to protrude from the shaft portion. A portion of the eccentric portion protruding from the shaft portion forms a stepped portion that is raised by one step from the outer peripheral surface of the shaft portion in a direction away from the center of the shaft portion. The powder conveying downstream end, which is one end of the blade portion, is connected to the powder conveying direction upstream end of the eccentric portion.

However, there is a possibility that the powder aggregates on the downstream side in the rotation direction of the conveying screw at the connecting portion between one end of the blade, such as the downstream end of the powder conveying portion of the blade, and the stepped portion such as the eccentric portion. rice field.

In order to solve the above-described problems, the present invention provides a conveying screw that includes a shaft portion and a blade portion spirally wound around the shaft portion and conveys powder toward one end of the blade portion, A stepped portion is provided at an axial position of one end of the blade portion, the stepped portion rising one step from the outer peripheral surface of the shaft portion in a direction away from the center of the shaft portion, and the stepped portion is located at one end of the blade portion in the circumferential direction. It is characterized in that it is formed outside the area from the part to a position advanced by a predetermined distance downstream in the rotational direction of the conveying screw.

According to the present invention, aggregation of powder can be suppressed.

1 is a schematic configuration diagram of a copier according to the present embodiment; FIG. FIG. 2 is a schematic diagram showing a schematic configuration of an image forming unit corresponding to yellow; (a) is a perspective view showing a state in which the toner container is installed in the toner replenishing device, and (b) is a schematic view. Sectional drawing which shows a part of conveyance nozzle and nozzle conveyance screw, and a vertical conveyance path. The schematic block diagram of the conventional nozzle conveyance screw. FIG. 4 is a diagram showing a state in which toner is aggregated in a wedge-shaped region; 4A and 4B are diagrams showing characteristic portions of the nozzle conveying screw of Example 1. FIG. 3 shows another configuration example of the first embodiment; The figure explaining the position of the circumferential direction of the area|region X which protrudes from the axial part of an eccentric part. FIG. 8 is a diagram showing a characteristic portion of the nozzle conveying screw of Example 2;

An embodiment of the present invention in which the present invention is applied to a copying machine (hereinafter referred to as a copying machine 500) as an image forming apparatus will be described below.
FIG. 1 is a schematic configuration diagram of a copying machine 500 of this embodiment. The copying machine 500 is composed of a copying machine main body (hereinafter referred to as a printer section 100), a paper feed table (hereinafter referred to as a paper feed section 200), and a scanner (hereinafter referred to as a scanner section 400) mounted on the printer section 100. .

In the toner container storage unit 70 provided in the upper portion of the printer unit 100, there are four developer storage containers corresponding to respective colors (yellow, magenta, cyan, and black) and toner containers 32 (Y, M, C, K) are detachably (exchangeably) installed. An intermediate transfer unit 85 is arranged below the toner container accommodating portion 70 .

The intermediate transfer unit 85 includes an intermediate transfer belt 48, four primary transfer bias rollers 49 (Y, M, C, K), a secondary transfer backup roller 82, a plurality of tension rollers, an intermediate transfer cleaning device, and the like. be. The intermediate transfer belt 48 is stretched and supported by a plurality of roller members, and is endlessly moved in the direction of the arrow in FIG. 1 by the rotational driving of a secondary transfer backup roller 82, which is one of the plurality of roller members.

In the printer section 100, image forming sections 46 (Y, M, C, and K), which are four image forming means corresponding to each color, are arranged in parallel so as to face the intermediate transfer belt 48 . Four toner replenishing devices 60 (Y, M, C, K) corresponding to the four toner containers 32 (Y, M, C, K) are arranged below the four toner containers 32 (Y, M, C, K). The toner stored in the toner container 32 (Y, M, C, K) is supplied to the image forming section 46 (Y) corresponding to each color by the toner supply device 60 (Y, M, C, K) corresponding to each color. , M, C, K) are supplied (replenished) into the developing device (powder using section).

Further, as shown in FIG. 1, the printer section 100 has an exposure device 47 as latent image forming means below the four image forming sections 46 . The exposure device 47 exposes the surface of the photoreceptor 41 (to be described later) based on the image information of the document image read by the scanner unit 400 or the image information input from an external device such as a personal computer. Forms an electrostatic latent image on the surface. The exposure device 47 provided in the printer section 100 uses a laser beam scanner system using a laser diode, but other configurations such as those using an LED array may be used as exposure means.

FIG. 2 is a schematic diagram showing a schematic configuration of the image forming section 46Y for yellow.
The image forming unit 46Y includes a drum-shaped photoreceptor 41Y as an image carrier. Further, the image forming unit 46Y has a structure in which a charging roller 44Y as charging means, a developing device 50Y as developing means, a photoreceptor cleaning device 42Y, a static elimination device, etc. are arranged around the photoreceptor 41Y. Then, an image forming process (charging process, exposure process, development process, transfer process, cleaning process) is performed on the photoreceptor 41Y to form a yellow image on the photoreceptor 41Y.

The other three image forming units 46 (M, C, K) have substantially the same configuration as the image forming unit 46Y for yellow except that the colors of toner used are different. An image of a color corresponding to each toner is formed on the photosensitive member 41 (M, C, K). Hereinafter, description of the other three image forming units 46 (M, C, K) will be appropriately omitted, and only the image forming unit 46Y corresponding to yellow will be described.

The photosensitive member 41Y is rotationally driven clockwise in FIG. 2 by a drive motor. Then, the surface of the photoreceptor 41Y is uniformly charged at a position facing the charging roller 44Y (charging step). After that, the surface of the photoreceptor 41Y reaches the irradiation position of the laser light L emitted from the exposure device 47, and an electrostatic latent image corresponding to yellow is formed by exposure scanning at this position (exposure step). After that, the surface of the photoreceptor 41Y reaches a position facing the developing device 50Y, and the electrostatic latent image is developed at this position to form a yellow toner image (developing step).

The four primary transfer bias rollers 49 (Y, M, C, K) of the intermediate transfer unit 85 sandwich the intermediate transfer belt 48 between them and the photoreceptors 41 (Y, M, C, K) to effect primary transfer. forming a nip. A transfer bias opposite in polarity to the toner is applied to the primary transfer bias rollers 49 (Y, M, C, K).

The surface of the photoreceptor 41Y on which the toner image is formed in the development process reaches the primary transfer nip facing the primary transfer bias roller 49Y with the intermediate transfer belt 48 interposed therebetween. is transferred onto the intermediate transfer belt 48 (primary transfer step). At this time, a small amount of untransferred toner remains on the photoreceptor 41Y. The surface of the photoreceptor 41Y that has transferred the toner image onto the intermediate transfer belt 48 at the primary transfer nip reaches a position facing the photoreceptor cleaning device 42Y. At this opposing position, the untransferred toner remaining on the photoreceptor 41Y is mechanically collected by the cleaning blade 42a (cleaning step). Finally, the surface of the photoreceptor 41Y reaches a position facing the static elimination device, and the residual potential on the photoreceptor 41Y is removed at this position. Thus, a series of image forming processes performed on the photoreceptor 41Y is completed.

Such an image forming process is performed in the other image forming units 46 (M, C, K) in the same manner as in the yellow image forming unit 46Y. That is, from the exposure device 47 arranged below the image forming units 46 (M, C, K), the laser light L based on the image information is emitted to the photoconductors of the image forming units 46 (M, C, K). 41 (M, C, K). More specifically, the exposure device 47 emits a laser beam L from a light source, scans the laser beam L with a rotationally driven polygon mirror, and scans the photoreceptors 41 (M, C, K) through a plurality of optical elements. ) above. After that, the toner images of respective colors formed on the photoreceptors 41 (M, C, K) through the developing process are transferred onto the intermediate transfer belt 48 .

At this time, the intermediate transfer belt 48 travels in the direction of the arrow in FIG. 1 and sequentially passes through the primary transfer nips of the primary transfer bias rollers 49 (Y, M, C, K). As a result, the toner images of the respective colors on the photoreceptors 41 (Y, M, C, K) are primarily transferred onto the intermediate transfer belt 48 so as to form color toner images on the intermediate transfer belt 48 .

The intermediate transfer belt 48 on which the toner images of each color are superimposed and transferred to form a color toner image reaches a position facing the secondary transfer roller 89 . At this position, the secondary transfer backup roller 82 sandwiches the intermediate transfer belt 48 with the secondary transfer roller 89 to form a secondary transfer nip. Then, the color toner image formed on the intermediate transfer belt 48 is transferred onto a recording medium P such as transfer paper conveyed to the position of the secondary transfer nip. At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 48 . After passing through the secondary transfer nip, the intermediate transfer belt 48 reaches the position of the intermediate transfer cleaning device, untransferred toner on its surface is collected, and a series of transfer processes performed on the intermediate transfer belt 48 are completed.

Next, the movement of the recording medium P will be explained.
The recording medium P conveyed to the secondary transfer nip described above passes from a paper feed tray 26 of a paper feed section 200 arranged below the printer section 100 via a paper feed roller 27, a pair of registration rollers 28, and the like. It is to be transported. Specifically, a plurality of sheets of the recording medium P are stored in the paper feed tray 26 while being stacked. 1, the uppermost recording medium P is conveyed toward the roller nip formed by the two rollers of the registration roller pair 28. As shown in FIG.

The recording medium P conveyed to the registration roller pair 28 is temporarily stopped at the roller nip position of the registration roller pair 28 whose rotational drive is stopped. Then, the registration roller pair 28 is rotationally driven in time with the timing when the color toner image on the intermediate transfer belt 48 reaches the secondary transfer nip, and the recording medium P is conveyed toward the secondary transfer nip. Thereby, a desired color toner image is transferred onto the recording medium P. FIG.

The recording medium P onto which the color toner image has been transferred at the secondary transfer nip is conveyed to the position of the fixing device 86 . In the fixing device 86, the color toner image transferred to the surface is fixed on the recording medium P by heat and pressure from the fixing belt and pressure roller. After passing through the fixing device 86 , the recording medium P passes between the rollers of the paper discharge roller pair 29 and is discharged outside the device. The recording medium P ejected outside the apparatus by the paper ejection roller pair 29 is sequentially stacked on the stack section 30 as an output image. Thus, a series of image forming processes in copier 500 are completed.

Next, the configuration and operation of the developing device 50 in the image forming section 46 will be described in more detail. Although the image forming unit 46Y corresponding to yellow will be described as an example here, the same applies to the image forming units 46 (M, C, K) for other colors.

The developing device 50Y, as shown in FIG. 2, comprises a developing roller 51Y, a doctor blade 52Y, two developer conveying screws 55Y, a toner density detection sensor 56Y, and the like. The developing roller 51Y faces the photoreceptor 41Y, and the doctor blade 52Y faces the developing roller 51Y. Also, the two developer conveying screws 55Y are arranged in the two developer accommodating portions (53Y, 54Y). The developing roller 51Y is composed of a magnet roller fixed inside, a sleeve rotating around the magnet roller, and the like. A two-component developer G composed of carrier and toner is accommodated in the first developer accommodation portion 53Y and the second developer accommodation portion 54Y. The second developer container 54Y communicates with the outlet 66 (see FIG. 3) of the toner replenishing device through an opening formed above. Further, the toner concentration detection sensor 56Y detects the toner concentration in the developer G inside the second developer container 54Y.

The developer G in the developing device 50 circulates between the first developer storage portion 53Y and the second developer storage portion 54Y while being agitated by the two developer transport screws 55Y. The developer G in the first developer containing portion 53Y is supplied onto the surface of the sleeve of the developing roller 51Y by the magnetic field formed by the magnet roller in the developing roller 51Y while being conveyed to one side of the developer conveying screw 55Y. be done. The sleeve of the developing roller 51Y is driven to rotate counterclockwise as indicated by the arrow in FIG. 2, and the developer G carried on the developing roller 51Y moves on the developing roller 51Y as the sleeve rotates. At this time, the toner in the developer G is charged to a potential opposite in polarity to the carrier by triboelectrification with the carrier in the developer G, and is electrostatically attracted to the carrier, and is formed on the developing roller 51Y. It is carried on the developing roller 51Y together with the carrier attracted by the magnetic field.

The developer G carried on the developing roller 51Y is transported in the direction of the arrow in FIG. 2 and reaches the doctor portion where the doctor blade 52Y and the developing roller 51Y face each other. The amount of the developer G on the developing roller 51Y is adjusted to an appropriate amount when passing through the doctor portion, and is then conveyed to the developing area facing the photoreceptor 41Y. In the development area, the toner in the developer G is attracted to the latent image formed on the photoreceptor 41Y by the development electric field formed between the development roller 51Y and the photoreceptor 41Y. As the sleeve rotates, the developer G remaining on the surface of the developing roller 51Y that has passed through the developing area reaches above the first developer container 53Y and is separated from the developing roller 51Y at this position.

The developer G in the developing device 50Y is adjusted so that the toner density is within a predetermined range. Specifically, according to the amount of toner contained in the developer G in the developing device 50Y consumed by development, the toner contained in the toner container 32Y is supplied to the second developer containing portion via the toner replenishing device 60Y, which will be described later. 54Y is replenished.
The toner replenished in the second developer containing portion 54Y is mixed and agitated with the developer G by the two developer conveying screws 55Y, and flows through the first developer containing portion 53Y and the second developer containing portion 54Y. circulate between

The toner in each toner container 32 (Y, M, C, K) installed in the toner container housing portion 70 of the printer section 100 is consumed by the toner in the developing device 50 (Y, M, C, K) of each color. Accordingly, it is replenished appropriately into each developing device 50 (Y, M, C, K). At this time, the toner in each toner container 32 (Y, M, C, K) is replenished by the toner replenishing device 60 (Y, M, C, K) provided for each toner color.

Next, the toner supply device 60 (Y, M, C, K) will be described.
FIG. 3(a) is a perspective view showing a state in which the toner container 32 is installed in the toner replenishing device 60, which is a powder conveying device, and FIG. 3(b) is a schematic view. Although the toner transport direction of the intermediate transport path 65 is originally a direction perpendicular to the paper surface of FIG. 3B, in FIG. The direction is set to be the same direction as the carrier nozzle 61 . Note that the four toner replenishing devices 60 (Y, M, C, K) and the toner containers 32 (Y, M, C, K) have substantially the same structure except that the toner colors used in the image forming process are different. . Therefore, the color codes Y, M, C, and K will be omitted from the description below.

The toner replenishing device 60 has a conveying nozzle 61 as a first conveying path, a vertical conveying path 64 as a connecting conveying path, and a relay conveying path 65 as a second conveying path. When the toner container 32, which is a powder container, is attached to the toner container accommodating portion 70 of the printer section 100, the conveying nozzle 61 of the toner replenishing device 60 is inserted from the tip side of the toner container 32 in conjunction with the attachment operation. be. Thereby, the inside of the toner container 32 and the inside of the conveying nozzle 61 are communicated with each other.

The toner container 32 is a substantially cylindrical toner bottle. It is mainly composed of a container front end cover 34 that is non-rotatably held in the toner container accommodating portion 70 and a container main body 33 integrally formed with a container gear 301 . The container body 33 is held relatively rotatably with respect to the container front end side cover 34 .

The container body 33 is rotationally driven by inputting rotational drive from the driving device to the container gear provided in the container body 33 . As the container main body 33 rotates, the toner accommodated inside the container main body 33 is moved along the longitudinal direction of the container main body 33 by the helical projections 302 formed in a spiral shape on the inner peripheral surface of the container main body 33 . transported to 61.

A scooping portion is provided on the container tip side cover side of the container body 33 to scoop up the toner conveyed to the container tip side cover side by the rotation of the container body 33 . This scooping-up portion scoops up the toner above the conveying nozzle 61 inserted into the toner container, and drops it into a nozzle opening 62 as an intake port provided at the end of the conveying nozzle 61 on the side of the toner container, whereby the toner is conveyed. Toner is supplied into the nozzle 61 .

A nozzle conveying screw 164 serving as a first conveying member is arranged in the conveying nozzle 61, and a rotational drive is input from a driving device to a first screw gear 98 fixed to the shaft portion of the conveying nozzle 61, thereby rotating the nozzle. The conveying screw 164 rotates to horizontally convey the toner supplied into the conveying nozzle 61 . The conveying direction downstream end of the conveying nozzle 61 is connected to the vertical conveying path 64 , and the toner conveyed by the nozzle conveying screw 164 drops down the vertical conveying path 64 under its own weight and is conveyed to the intermediate conveying path 65 .

A relay conveying screw 165 as a second conveying member is arranged in the relay conveying path 65, and rotational drive is input from a driving device to a second screw gear 96 fixed to the shaft portion of the relay conveying screw 165. , the relay conveying screw 165 rotates and conveys the toner supplied into the relay conveying path 65 in the horizontal direction. A discharge port 66 is provided at the downstream end of the relay conveying path 65 in the conveying direction.

The relay conveying path 65 is made of an elastic material such as elastomer rubber, and the relay conveying screw 165 is also made of an elastic material such as elastomer rubber, so that the relay conveying path 65 is elastically deformable. .

The diameter of the relay conveying path 65 is shorter than the diameter of the conveying nozzle 61 . Further, the number of rotations of the nozzle conveying screw 164 is 189 rpm, and the number of rotations of the intermediate conveying screw 165 is 237 rpm. . Note that the number of revolutions of each conveying screw is an example, and may be appropriately set according to the configuration of the apparatus.

FIG. 4 is a sectional view showing part of the transport nozzle 61 and the nozzle transport screw 164 and the vertical transport path 64. As shown in FIG.
As shown in FIGS. 3B and 4, a coil-shaped swinging member 166 is arranged in the vertical transport path 64 . An eccentric portion 164c is provided at the portion where the nozzle conveying screw 164 is connected to the vertical conveying path 64, and the hook portion 166a of the rocking member 166 is hooked on this eccentric portion 164c. By rotating the nozzle conveying screw 164 , the rocking member 166 moves up and down, and the toner in the vertical conveying path 64 can be loosened.

FIG. 5 is a schematic configuration diagram of a conventional nozzle conveying screw 164. As shown in FIG.
As shown in FIG. 5, the nozzle conveying screw 164 has a shaft portion 164a and an eccentric portion 164c. A main blade portion 164b and a reverse winding blade portion 164e are spirally wound around the shaft portion 164a. The main blade portion 164b is arranged on the left side of the eccentric portion 164c in the drawing and conveys the toner taken in from the nozzle opening 62 toward the right side in the drawing. The reverse winding blade portion 164e is arranged on the left side of the eccentric portion 164c in the drawing, and conveys the toner that has not fallen into the vertical conveying path 64 toward the right side in the drawing.

A portion of the eccentric portion 164c is larger than the outer diameter of the shaft portion 164a, and is eccentric in such a manner that a portion of the eccentric portion 164c protrudes from the shaft portion 164a. A sufficient swinging amount of the swinging member 166 is ensured.

Since part of the eccentric portion 164c projects from the shaft portion 164a, the hook portion 166a of the rocking member 166 hooked on the eccentric portion 164c falls off the eccentric portion 164c during assembly. There is a risk of Therefore, drop-off preventing portions 164d are provided at both ends of the eccentric portion 164c so as to protrude from the eccentric portion 164c. The drop-off preventing portion 164d serves as a stepped portion raised one step outward with respect to the shaft portion 164a.

Conventionally, the drop-off prevention portion 164d is provided around the shaft. An end portion of the main blade portion 164b on the side of the eccentric portion 164c is connected to the fall prevention portion 164d. Therefore, as shown in FIG. 6B, a wedge-shaped region A is formed downstream of the end of the main blade portion 164b on the side of the eccentric portion 164c in the direction of rotation of the screw. That is, as the axial width between the downstream side surface of the main blade portion 164b in the rotation direction and the upstream end surface in the toner conveying direction of the drop-off preventing portion 164d increases toward the upstream side in the screw rotation direction, the main blade portion 164b and the drop-off preventing portion 164d increase in width. It is a region where the interval between

The toner conveyed to the wedge-shaped area A by the main blade portion 164b is prevented from being conveyed by the falling-off prevention portion 164d as a stepped portion raised from the shaft portion 164a and stays there. As the nozzle conveying screw 164 rotates, the stagnant toner moves to a portion where the gap between the main blade portion 164b and the drop prevention portion 164d in the wedge-shaped region A becomes narrower, and the toner stagnant in the region A There was a problem that pressure was applied and aggregation as shown in FIG. 6 occurred. When this aggregated toner eventually falls off and is replenished to the developing device, there is a risk of causing abnormal images such as white spots and white streaks. In addition, there is a risk of clogging starting from this aggregated toner, and in the worst case, the aggregated toner prevents the conveying screw from rotating, and damages the conveying screw and the driving device that drives the conveying screw. I was afraid.

In particular, as shown in FIG. 4, when the height of the toner in the conveying nozzle is higher than the shaft portion 164a, toner aggregation in the wedge-shaped region A is likely to occur.

Therefore, in the present embodiment, a stepped portion is formed in the circumferential direction other than the portion corresponding to the region A where aggregation may occur. Hereinafter, the characteristic part of this embodiment will be described as Example 1 with reference to the drawings.

[Example 1]
FIG. 7 is a diagram showing a characteristic portion of the nozzle conveying screw of Example 1. FIG.
In FIG. 7, a portion of the drop-off preventing portion 164d is cut away, and the drop-off preventing portion 164d is not provided. With the configuration shown in FIG. 7, there is no stepped portion that hinders toner transportation in the region Z, which is a predetermined distance downstream in the rotational direction W from the end of the main blade portion 164b. As a result, the toner conveyed by the main blade portion 164b moves to the eccentric portion 164c and drops into the vertical conveying path 64 without staying. As a result, it is possible to suppress the occurrence of aggregation of toner on the upstream side in the toner conveying direction of the drop-off preventing portion 164d. In addition, since the drop-off preventing portion 164d is provided outside the region Z, it is possible to effectively prevent the swinging member 166 hooked on the eccentric portion 164c from dropping off from the eccentric portion 164c.

Note that the area Z may be appropriately determined according to the area where the pressure is applied to the toner by the step portion and the main blade portion 164b. For example, when the screw pitch of the main blade portion 164b is narrow and the inclination of the main blade portion 164b is steep, the narrow space between the main blade portion 164b and the step becomes longer in the circumferential direction. Therefore, the area sandwiched between the steps and the main blade portion 164b to apply pressure to the toner becomes longer in the circumferential direction. Therefore, in this case, the region Z is set longer in the circumferential direction than when the screw pitch of the main blade portion 164b is wide.

Moreover, if the drop-off preventing portion 164d is provided at an angle of 180° or more in the circumferential direction, the swinging member 166 can be prevented from dropping off from the eccentric portion 164c. Therefore, for example, as a configuration in which the drop-off preventing portion 164d is not provided even in a region of the main blade portion 164b advanced by a predetermined distance to the upstream side in the rotation direction W of the nozzle conveying screw, a step of a predetermined range is provided on both sides in the rotation direction of the main blade portion 164b. It is good also as a structure without.

FIG. 8 shows another configuration example of the first embodiment.
8, the shaft portion 164a is mounted from the downstream side in the rotation direction W of the nozzle conveying screw so that the outer diameter of the shaft portion corresponding to the wedge-shaped region A is the same as the outer diameter of the drop-off prevention portion 164d. gradually increase the outer diameter of the Specifically, the region α between the end surface of the falling prevention portion 164d of the shaft portion 164a on the upstream side in the toner conveying direction and the side surface of the main blade portion 164b on the downstream side in the screw rotation direction corresponds to the wedge-shaped region A. , the outer diameter dimension gradually increases in the circumferential direction.
With such a configuration as well, it is possible to eliminate a stepped portion that hinders the transportation of toner in the region Z, which is a predetermined distance from the end of the main blade portion 164b in the rotational direction. As a result, the toner conveyed by the main blade portion 164b moves to the eccentric portion 164c and drops into the vertical conveying path 64 without staying. As a result, it is possible to suppress the occurrence of toner agglomeration in front of the fall prevention portion 164d.

FIG. 9 is a diagram illustrating the circumferential position of the region X protruding from the shaft portion 164a of the eccentric portion 164c. FIG. 9 is a cross-sectional view of the main blade portion 164b at the downstream end position in the toner conveying direction. 9(a) and 9(b) show the case where the eccentric portion 164c does not have the anti-falling portion 164d at both ends, and FIGS. 9(c) and 9(d) show It shows the case where there is a drop-off preventing portion 164d.
As shown in FIG. 9A, if a region X protruding from the shaft portion 164a of the eccentric portion 164c overlaps a region Z downstream of the end of the main blade portion 164b by a predetermined distance in the rotational direction W. The wedge-shaped region A is formed by the stepped portion of the eccentric portion 164c protruding from the shaft portion 164a and the main blade portion 164b.

Further, as shown in FIG. 9C, even when the drop-off preventing portion 164d is notched and the drop-off preventing portion 164d is not provided in the region Z, the region X protruding from the shaft portion 164a of the eccentric portion 164c is the main part. When the blade portion 164b overlaps with the region Z downstream of the rotational direction W by a predetermined distance from the end portion of the blade portion 164b, the above-mentioned A wedge-shaped region A is formed.

In this way, when the region X protruding from the shaft portion 164a of the eccentric portion 164c overlaps with the region Z, which is a predetermined distance from the end of the main blade portion 164b in the rotational direction, the wedge-shaped region A is formed. As described above, toner aggregation may occur.

Therefore, as shown in FIGS. 9(b) and 9(d), in the circumferential direction, the region X protruding from the shaft portion 164a of the eccentric portion 164c is located downstream in the rotation direction W from the end portion of the main blade portion 164b. The eccentric portion 164c is configured so as not to enter the region Z advanced by a predetermined distance. As a result, the wedge-shaped region A is not formed by the blade portion and the stepped portion formed by the region X projecting from the shaft portion 164a of the eccentric portion 164c. As a result, the toner conveyed by the main blade portion 164b moves to the eccentric portion 164c and drops into the vertical conveying path 64 without staying. As a result, it is possible to suppress the occurrence of toner agglomeration in front of the fall prevention portion 164d.

Next, another technique for suppressing toner aggregation at the upstream end portion of the drop-off preventing portion 164d in the toner conveying direction will be described as a second embodiment.

[Example 2]
FIG. 10 is a diagram showing a characteristic portion of the nozzle conveying screw of Example 2. FIG.
As shown in FIG. 10, in the second embodiment, a predetermined gap d is provided in the axial direction between the toner conveying direction downstream end portion 164b1 of the main blade portion 164b and the stepped portion formed by the fall prevention portion 164d. It is a thing. A gap d between the downstream end portion 164b1 of the main blade portion 164b in the toner conveying direction and the stepped portion formed by the fall prevention portion 164d is preferably 2 mm or more. Further, if the downstream end 164b1 of the main blade portion 164b in the toner conveying direction is located in the vertical conveying path 64, the toner can be conveyed to the vertical conveying path 64 by the main blade portion 164b. Therefore, the axial length from the end of the eccentric portion 164c on the main blade portion side to the side wall of the vertical conveying path 64 on the main blade portion 164b side is set to 2 mm or more. As a result, the gap d can be increased by 2 mm or more, and the toner can be conveyed to the vertical conveying path 64 by the main blade portion 164b.

In the second embodiment, a gap for releasing toner is formed on the upstream side in the rotation direction of the screw in the wedge-shaped area A that narrows the gap between the main blade portion 164b and the drop prevention portion 164d. As a result, toner that has been stagnated due to obstruction of transportation by the stepped portion of the drop-off preventing portion 164d passes through the gap d between the downstream end portion 164b1 of the main blade portion 164b in the toner transport direction and the stepped portion of the drop-off preventing portion 164d. As a result, it is possible to suppress an increase in the pressure applied to the toner in the wedge-shaped region A, and it is possible to suppress the occurrence of toner aggregation in the wedge-shaped region A.

As for the reverse winding blade portion 164e, the amount of toner conveyed to the eccentric portion 164c is small. Therefore, the height of the toner in the region of the reverse winding blade portion 164e is equal to or less than the shaft portion 164a. Therefore, the toner conveyed by the reverse winding blade portion 164e is hardly blocked by the steps of the fall prevention portion. Therefore, the toner is less likely to aggregate in the wedge-shaped region formed by the step between the reverse winding blade portion 164e and the drop-off preventing portion 164d. Therefore, in this embodiment, the configurations of Examples 1 and 2 are not adopted in the area of the reverse winding blade portion 164e. However, when there is a possibility that the toner aggregates in the wedge-shaped region formed by the step between the reverse winding blade portion 164e and the fall prevention portion 164d, the configurations of the first and second embodiments described above are appropriately applied. may

In the above-described embodiment, an example in which the present invention is applied to a toner replenishing device that conveys toner in a toner container to a developing device has been described. The present invention can also be applied to conveying devices.

What has been described above is only an example, and each of the following aspects has a unique effect.
(Aspect 1)
A conveying screw such as a nozzle conveying screw 164 which has a shaft portion 164a and a blade portion such as a main blade portion 164b spirally wound around the shaft portion 164a and conveys powder such as toner toward one end of the blade portion. has a stepped portion such as a drop-off prevention portion 164d raised one step from the outer peripheral surface of the shaft portion 164a in a direction away from the center of the shaft portion 164a at one end portion in the axial direction such as the downstream end portion of the blade portion in the toner conveying direction. The stepped portion is formed outside the region Z from one end of the blade portion in the circumferential direction to a position a predetermined distance downstream in the rotational direction of the conveying screw.
A shaft portion 164a extends away from the center of the shaft portion 164a in a region (region Z shown in FIG. 7B) from one end of the blade portion such as the main blade portion 164b to a predetermined position on the downstream side in the rotation direction of the conveying screw. When a stepped portion that is one step higher than the outer peripheral surface of the blade is formed, the space formed by the end surface of the stepped portion on the upstream side in the conveying direction and the side surface of the blade portion on the downstream side in the conveying direction becomes the following space. . That is, a wedge-shaped space (Fig. 5 is a wedge-shaped region A). Powder such as toner that has moved into the wedge-shaped space as the conveying screw rotates is prevented from moving in the axial direction by the stepped portion, and stays in the wedge-shaped space. As the conveying screw rotates, the powder accumulated in the wedge-shaped space enters into a portion where the width in the axial direction between the end surface of the stepped portion of the wedge-shaped space and the side surface of the blade portion is narrower and exerts pressure. receive. As a result, there is a possibility that the powder aggregates in this wedge-shaped space.
On the other hand, in Mode 1, no stepped portion is formed in the region Z from one end of the blade portion to the position a predetermined distance downstream in the rotational direction of the conveying screw, so the above-described wedge-shaped space is not formed. . Thereby, it is possible to suppress the occurrence of agglomeration of the powder.

(Aspect 2)
In Aspect 1, an eccentric portion 164c that partially protrudes and is eccentric with respect to the outer peripheral surface of the shaft portion 164a is provided at one end portion, which is the downstream end portion in the toner conveying direction, of the blade portions such as the main blade portion 164b. and a region X protruding from the outer peripheral surface of the shaft portion 164a of the eccentric portion 164c. The positions in the circumferential direction are different from each other.
According to this, as described with reference to FIG. 9, the portion of the eccentric portion 164c protruding from the outer peripheral surface of the shaft portion 164a extends from the outer peripheral surface of the shaft portion 164a in the direction away from the center of the shaft portion 164a. It becomes a step part that goes up one step. Therefore, the region X protruding from the outer peripheral surface of the shaft portion of the eccentric portion 164c extends from one end of the blade portion such as the main blade portion 164b to a position a predetermined distance downstream in the rotation direction of the conveying screw. When overlapped with the region Z, a wedge-shaped region A is formed by the blade portion and the stepped portion formed by the portion of the eccentric portion 164c protruding from the outer peripheral surface of the shaft portion. As a result, the wedge-shaped region A may cause aggregation of the powder.
On the other hand, in mode 2, a region Z from one end of the blade portion to a position advanced by a predetermined distance downstream in the rotational direction of the conveying screw and a region Z protruding from the outer peripheral surface of the shaft portion 164a of the eccentric portion 164c. Since the position in the circumferential direction of the region X is different from each other, the region Z does not have a stepped portion. As a result, the wedge-shaped region A described above is not formed, and the powder can be conveyed by the blades without the toner remaining. As a result, it is possible to suppress the occurrence of agglomeration of powder.

(Aspect 3)
In Aspect 2, the eccentric portion 164c is provided at both ends in the axial direction with drop-off prevention portions 164d that prevent the swinging member 166 that protrudes from the eccentric portion 164c and is hooked on the eccentric portion 164c from dropping off from the eccentric portion 164c. The drop-off prevention portion 164d formed at the blade-side end of the main blade portion 164b or the like is located outside the region Z from the blade portion to a position a predetermined distance downstream in the rotational direction of the conveying screw in the circumferential direction. formed.
According to this, as described with reference to FIG. 7, the drop-off preventing portion 164d becomes a stepped portion that rises by one step from the outer peripheral surface of the shaft portion 164a in the direction away from the center of the shaft portion 164a. Therefore, the drop-off prevention portion 164d is formed in a region Z from one end of the blade portion such as the main blade portion 164b on the downstream side in the toner conveying direction to a predetermined position advanced downstream in the rotation direction of the conveying screw. As a result, a wedge-shaped area A is formed by the stepped portion formed by the fall prevention portion 164d and the blade portion. As a result, the wedge-shaped region A may cause aggregation of the powder.
On the other hand, in mode 3, the drop-off prevention portion 164d formed at the blade portion side end portion, such as the end portion of the eccentric portion 164c on the downstream side in the toner conveying direction, is moved from one end portion of the blade portion toward the downstream side in the rotation direction of the conveying screw. It is formed in areas other than the area Z up to a position advanced by a predetermined distance. As a result, there is no stepped portion due to the drop-off prevention portion 164d in the region Z, and the wedge-shaped region A described above is not formed. Therefore, the powder can be conveyed by the blade portion without the toner staying. As a result, it is possible to suppress the occurrence of agglomeration of powder.

(Aspect 4)
In Mode 1, from one end of the blade portion of the shaft portion 164a between the side surface of the blade portion such as the main blade portion 164b on the downstream side in the rotation direction of the conveying screw and the end surface of the stepped portion on the upstream side in the powder conveying direction The outer diameter of the shaft portion is gradually increased in the circumferential direction so that the outer diameter of the conveying screw to a position a predetermined distance downstream in the rotational direction is the same as the outer diameter of the stepped portion. rice field.
According to this, as described with reference to FIG. 8, there is no step in the region Z from the blade portion to the position a predetermined distance downstream in the rotational direction of the conveying screw, and the above-described wedge-shaped region A is not formed. . As a result, the fluted powder can be conveyed by the blades without the toner staying. As a result, it is possible to suppress the occurrence of agglomeration of powder.

(Aspect 5)
A conveying screw that includes a shaft portion 164a and a blade portion such as a main blade portion 164b spirally wound around the shaft portion 164a, and conveys powder toward one end of the blade portion. It has a stepped portion that rises one step from the outer peripheral surface of the shaft portion 164a in the direction, and has a predetermined gap d between one end of the blade portion and the stepped portion.
According to this, as described with reference to FIG. 10, the powder whose transportation is hindered by the stepped portion passes through the gap d between the blade portion and the stepped portion, and is moved downstream in the rotation direction of one end of the blade portion. stagnation of the powder can be suppressed on the downstream side of the blade, and aggregation of the toner on the downstream side in the rotation direction of the one end of the blade can be suppressed.

(Aspect 6)
In a powder conveying device such as a toner replenishing device 60 having a conveying screw such as a nozzle conveying screw 164 inside and a conveying path such as a conveying nozzle 61 for conveying powder,
As the conveying screw, the conveying screw according to any one of Modes 1 to 5 was used.
According to this, it is possible to suppress the occurrence of agglomeration of powder in the conveying path.

(Aspect 7)
In mode 6, the height of the powder in the conveying path such as the conveying nozzle 61 is higher than the shaft portion 164a of the conveying screw.
According to this, as described in the embodiment, it is possible to suppress the occurrence of agglomeration of powder in the conveying path.

(Aspect 8)
In an image forming apparatus comprising an image forming means such as an image forming unit 46 for forming a toner image and a toner conveying device such as a toner replenishing device for conveying toner, the powder according to any one of aspects 1 to 7 is used as the toner conveying device. A body transfer device was used.
According to this, aggregation of the toner can be suppressed.

32 : Toner container 33 : Container main body 34 : Container tip side cover 46 : Imaging unit 50 : Developing device 60 : Toner replenishing device 61 : Conveying nozzle 62 : Nozzle opening 64 : Vertical conveying path 65 : Relay conveying path 66 : Discharge port 70: Toner container accommodating portion 100: Printer portion 164: Nozzle conveying screw 164a: Shaft portion 164b: Main blade portion 164b1: Toner conveying direction downstream side end portion 164c: Eccentric portion 164d: Falling prevention portion 164e: Reverse winding blade portion 165: Relay Conveying screw 166: Swinging member 166a: Hook portion 301: Container gear 302: Spiral projection 400: Scanner portion A: Wedge-shaped region Z: Region d up to a predetermined distance downstream in the rotational direction from the main blade portion: Main blade portion Axial clearance between the downstream end of the toner conveying direction and the step

JP 2019-159129 A

Claims (8)

a shaft;
and a blade portion spirally wound around the shaft portion,
In the conveying screw for conveying powder toward one end of the blade,
a stepped portion raised by one step from the outer peripheral surface of the shaft portion in a direction away from the center of the shaft portion at an axial position of one end portion of the blade portion;
The conveying screw, wherein the stepped portion is formed outside a region extending in the circumferential direction from one end of the blade portion to a position a predetermined distance downstream in the rotational direction of the conveying screw. In the conveying screw according to claim 1,
An eccentric part protruding partly from the outer peripheral surface of the shaft part is provided at one end of the blade part,
a position in the circumferential direction of a region from one end of the blade portion to a position a predetermined distance downstream in the rotational direction of the conveying screw; A conveying screw characterized in that the circumferential positions of the conveying screws are different from each other. In the conveying screw according to claim 2,
At both ends of the eccentric portion in the axial direction, drop-off prevention portions are provided to prevent the swinging member, which protrudes from the eccentric portion and is hooked on the eccentric portion, from dropping off from the eccentric portion,
The drop-off prevention portion formed at the end of the eccentric portion on the blade portion side is formed outside a region in the circumferential direction from the blade portion to a position downstream in the rotational direction of the conveying screw by a predetermined distance. A conveying screw, characterized in that In the conveying screw according to claim 1,
Downstream in the rotation direction of the conveying screw from one end of the blade portion of the shaft portion between the side surface of the blade portion on the downstream side in the rotation direction of the conveying screw and the end surface of the stepped portion on the upstream side in the powder conveying direction A conveying screw characterized in that the outer diameter dimension of the shaft portion is gradually increased so that the outer diameter dimension up to a position a predetermined distance to the side is the same as the outer diameter dimension of the stepped portion. a shaft;
and a blade portion spirally wound around the shaft portion,
In the conveying screw for conveying powder toward one end of the blade,
having a stepped portion raised by one step from the outer peripheral surface of the shaft portion in a direction away from the center of the shaft portion;
A conveying screw characterized by having a predetermined gap between one end of the blade portion and the stepped portion. In a powder conveying device provided with a conveying screw inside and a conveying path for conveying powder,
A powder conveying apparatus, wherein the conveying screw according to any one of claims 1 to 5 is used as the conveying screw. In the powder conveying device according to claim 6,
The conveying path is a horizontal conveying path that conveys the powder in a horizontal direction,
A powder conveying apparatus, wherein the height of the powder in the horizontal conveying path is higher than the lower end of the shaft portion of the conveying screw. an image forming means for forming a toner image;
In an image forming apparatus comprising a toner conveying device that conveys toner,
8. An image forming apparatus using the powder conveying device according to claim 6 or 7 as the toner conveying device.

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