JP2014026231A - Powder conveying device, developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder conveying device which is constituted such that it can prevent powder from clogging in a powder conveyance path with a simple structure, and when toner is used as powder for example, prevent conveyance abnormality of the toner to be conveyed so as to prevent damage to a driving member used for the conveyance due to an increase in load to the driving member and stabilize developing density.SOLUTION: A powder conveying device includes a powder conveyance path 101Y provided between the upstream side 9Y2 and the downstream side 40Y in a powder conveying direction so as to communicate with the upstream side and the downstream side. An amount of powder per unit time on the downstream side in the conveying direction is set to be larger than the introduced amount of powder per unit time on the upstream side in the conveying direction.

Description

  The present invention relates to a powder conveying device, a developing device, a process cartridge, and an image forming apparatus, and more particularly to a configuration that can prevent clogging or the like when conveying toner or the like.

An image forming apparatus is one of apparatuses having a configuration for conveying and using powder.
Examples of the image forming apparatus include a copying machine, a printer, a facsimile apparatus, and a printing machine that use an electrophotographic system.
In the image forming apparatus, the electrostatic latent image formed on the photosensitive member, which is a latent image carrier, is subjected to visible image processing by a developing device, and a recorded output can be obtained by transferring the visible image to a sheet or the like. .

A developing device corresponds to an apparatus using powder in the image forming apparatus.
In the developing device, a two-component developer in which a toner and a carrier are mixed or a one-component developer not containing a carrier is used.

The developing device includes a developer carrier and a developer supply member in a developer tank that forms a developer container, and the developer supply member directs the developer or toner carried on the surface toward the development sleeve. A roller that can be supplied is used.
When using a two-component developer, in addition to the developer supply member that supplies the developer toward the developing sleeve as a developer supply member, the developer is agitated and conveyed and the toner to be supplied is agitated and mixed. A developer stirring and conveying member having a function of maintaining the developer concentration at a predetermined concentration is provided.

  Since storing replenishment toner in a part of the developing device leads to an increase in the size of the developing device, a powder container such as a toner tank is also received at a position different from the developing device. In addition, a configuration is known in which connection is made by a conveyance pipe line using a tube or the like (for example, Patent Document 1).

  By the way, in a powder conveyance device using a conveyance line such as a tube, the case where the above-described toner tank is used will be described. A conveyance line is provided between the discharge port of the toner tank and the developing insertion side of the development device. However, the toner deposited on the discharge port is likely to clog on the upstream side in the transport direction because of poor fluidity and tendency to aggregate.

Therefore, as a configuration for solving the above-described problem, it is conceivable to move the upstream side and the downstream side in the transport direction closer to each other in the transport direction before being aggregated.
However, with this configuration, it can be said that it is difficult due to layout restrictions. For this reason, the transport pipeline connecting the upstream side and the downstream side in the transport direction may be inclined.

In the inclined portion of the conveyance pipeline, the toner that is about to fall at a stretch is prevented from falling by its own weight by using a conveyance member as disclosed in Patent Document 1.
As a result, the toner becomes insufficiently charged due to an increase in fluidity due to an increase in the mixing ratio with air, which is a phenomenon obtained when flowing at a stroke, and a part of the toner due to an increase in moving speed causes excessive fluidity. It is possible to suppress the flow to the developing device side.

However, in the configuration in which the conveyance member is provided in the conveyance pipeline, since the curved path exists in the middle of the conveyance pipeline, the toner accumulated on the upstream side in the toner conveyance direction corresponding to the toner tank side moves along the curved path. Clogged easily due to resistance.
In particular, since downsizing of the apparatus has been desired in recent years, a configuration in which a curved path is provided in the conveyance pipe line is often used, and the above-described toner clogging often occurs. Toner clogging is also caused by an increase in the degree of aggregation due to the influence of temperature and humidity in the vicinity.

  An object of the present invention is to prevent the powder from clogging in the powder conveyance path with a simple configuration in view of the problems in the conventional powder conveyance structure, for example, when toner is used as powder. Patent application title: POWDER CONVEYING APPARATUS AND DEVELOPING APPARATUS PROVIDED WITH PREVENTION OF CARRIER TONER CONVEYED TO PREVENT DAMAGE DURING INCREASED LOAD ON DRIVE MEMBER USED FOR CONVEYING AND STABILIZED DEVELOPMENT DENSITY Another object is to provide a process cartridge and an image forming apparatus.

In order to achieve this object, the present invention is a powder conveying apparatus provided with a powder conveying path communicating with the upstream side and the downstream side between the upstream side and the downstream side in the powder conveying direction,
In the powder conveying apparatus, the relationship is set such that the amount of powder per unit time on the downstream side in the conveying direction is larger than the amount of powder introduced per unit time on the upstream side in the conveying direction. is there.

  According to the present invention, since the amount of powder on the downstream side in the conveyance direction of the powder is larger than the amount of powder on the upstream side in the conveyance direction, the mobility of the toner in the conveyance path, that is, the upstream It is possible to improve the ease of powder flow on the side. As a result, it is possible to prevent poor conveyance due to stagnation or clogging of powder that easily aggregates, thereby preventing an increase in load on the driving member and insufficient conveyance of the powder.

It is a schematic diagram for explaining one embodiment of an image forming apparatus using a developing device provided with a powder conveyance device according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining a configuration of a process cartridge used in the image forming apparatus shown in FIG. 1. It is a perspective view for demonstrating the principal part structure of the image development apparatus using the powder conveying apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the principal part structure of the powder conveying apparatus shown in FIG. It is a figure for demonstrating one of the characteristics of the powder conveying apparatus which concerns on embodiment of this invention. It is a figure for demonstrating one of the principal part modifications of the powder conveying apparatus shown in FIG. It is a figure for demonstrating another one of the principal part modification of the powder conveying apparatus shown in FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the embodiments shown in the drawings.
FIG. 1 shows a laser printer which is one of image forming apparatuses according to an embodiment of the present invention and can form images of a plurality of colors. The present invention is not limited to a printer as an image forming apparatus, but includes a copying machine, a facsimile machine, a printing machine, and an apparatus that combines these functions.

  In FIG. 1, an image forming apparatus 100 uses an image carrier capable of forming an image as an image corresponding to each color separated into yellow, magenta, cyan, and black. In the configuration shown in FIG. 1, photosensitive drums 20Y, 20M, 20C, and 20Bk as photosensitive drums are used as the image carrier, and each of these photosensitive drums is arranged in a tandem structure.

  In the image forming apparatus 100 shown in FIG. 1, the visible images formed on the photosensitive drums 20Y, 20M, 20C, and 20Bk move in the direction of the arrow A1 while facing the photosensitive drums 20Y, 20M, 20C, and 20Bk. A primary transfer process is performed on an intermediate transfer body (hereinafter referred to as an intermediate transfer belt) 11 using a possible endless belt, and each image is superimposed and transferred to a transfer sheet S on which a recording sheet or the like is used. On the other hand, batch transfer is performed by executing a secondary transfer process.

Around each photosensitive drum, an apparatus for image forming processing is arranged according to the rotation of the photosensitive drum.
Now, with reference to FIG. 2 showing the configuration of a process cartridge, which will be described later, the photosensitive drum 20Y that performs yellow image formation will be described as an object. A primary transfer roller 12Y and a cleaning device 50Y are disposed.

  For writing performed after charging, a writing device 8 described later is used. The photoconductive drum 20Y is also provided with a static eliminator (not shown) that performs static erasure after the residual toner is removed by the cleaning device 50Y.

In the configuration shown in FIG. 2, the photosensitive drum 20Y, the charging device 30Y opposite to the photosensitive drum 20Y, the developing device 40Y including the developing sleeve 40Y1, and the cleaning device 50Y are collectively stored in a process cartridge.
The process cartridge is configured to be detachable from the image forming apparatus 100 so that consumable parts can be exchanged collectively. In FIG. 2, a symbol L indicates a writing laser beam emitted from the writing device 8.

  In the superimposing transfer to the intermediate transfer belt 11, visible images formed on the photosensitive drums 20 </ b> Y, 20 </ b> M, 20 </ b> C, and 20 </ b> Bk are in the same position on the intermediate transfer belt 11 in the process of moving the intermediate transfer belt 11 in the A1 direction. It is transcribed again.

For the superimposing transfer, primary transfer rollers 12Y, 12M, 12C, and 12Bk disposed to face the respective photosensitive drums 20Y, 20M, 20C, and 20Bk with the intermediate transfer belt 11 interposed therebetween are used.
The primary transfer rollers 12Y, 12M, 12C, and 12Bk are applied with a transfer bias by shifting the timing from the upstream side toward the downstream side in the A1 direction.

20Y, 20M, 20C, and 20Bk are arranged in this order from the upstream side in the A1 direction.
Each of the photosensitive drums 20Y, 20M, 20C, and 20Bk is provided in a process cartridge that constitutes an image station for forming yellow, magenta, cyan, and black images, respectively.

  The image forming apparatus 100 includes four image forming stations that perform image forming processing for each color, and an intermediate transfer belt 11 and the above-described primary transfer rollers 12Y and 12Y as transfer devices to which images from the respective image forming stations are transferred. 12M, 12C and 12Bk.

  The intermediate transfer belt 11 and the primary transfer rollers 12Y, 12M, 12C, and 12Bk are incorporated in the transfer belt unit 10, and the transfer belt unit 10 is used for maintenance inspection and replacement of parts of the image forming apparatus main body. It is designed to be detachable.

The image superimposed and transferred onto the intermediate transfer belt 11 is collectively transferred onto a transfer sheet by a secondary transfer roller 5 as a secondary transfer unit that can be rotated around the intermediate transfer belt 11.
After the batch transfer, the intermediate transfer belt 11 is subjected to removal of untransferred toner by an intermediate transfer belt cleaning device 13 disposed opposite thereto.

  The writing device 8 in this embodiment is equipped with a semiconductor laser as a light source, a coupling lens, an fθ lens, a toroidal lens, a mirror, a rotating polygon mirror, and the like.

  Writing light L corresponding to each color from the writing device 8 to each of the photosensitive drums 20Y, 20M, 20C, and 20Bk (in FIG. 2, a reference is given to a process cartridge for yellow image formation. The same applies to process cartridges used in other image stations), and electrostatic latent images are formed on the photosensitive drums 20Y, 20M, 20C, and 20Bk.

The image forming apparatus 100 is provided with a sheet feeding device 61 that transfers toward the arrangement position of the secondary transfer roller 5 and feeds S.
The sheet feeding device 61 is provided with a paper feed cassette on which the transfer paper S is loaded and a registration roller pair 4 disposed in the transfer paper transport path.

  The registration roller 4 is configured to transfer the transfer sheet S fed from the sheet feeding device 61 to each of the photosensitive drums 20Y, 20M, 20C, and 20Bk and the intermediate transfer belt at a predetermined timing in accordance with the toner image formation timing by the image station. 11 is a member that is fed out toward the transfer portion between the two. Although not shown, a sensor for detecting that the leading edge of the transfer paper S has reached the registration roller pair 4 is provided in the conveyance path of the transfer paper S.

  The image forming apparatus 100 includes a fixing device 6 as a heat roller fixing type fixing unit for fixing the toner image onto the transfer sheet S on which the toner image is transferred, and the fixed transfer sheet S of the image forming apparatus 100. A paper discharge roller 7 that discharges to the outside of the main body, and a paper discharge tray 17 that is disposed on the top of the main body of the image forming apparatus 100 and loads the transfer paper S discharged to the outside of the main body of the image forming apparatus 100 by the paper discharge roller 7. Is provided.

  On the other hand, the developing device 40Y provided in the process cartridge shown in FIG. 2 uses a developing tank 40A in which a space capable of storing the developer is partitioned in the horizontal direction. A supply member 40D and a developer stirring / conveying member 40E are respectively disposed.

The developer supply member 40D and the developer agitating / conveying member 40E are configured by a screw auger, and the developer supply member 40D is made to rise like a brush by a magnetic pole provided inside the developer sleeve 40Y1 that is a developer carrier. Supply developer.
The developer stirring / conveying member 40E stirs and conveys the developer overflowing from the space on the developer supply member 40D side at the partition in the developing tank.

In the space where the developer agitating and conveying member 40E is arranged, replenishment toner is introduced from a toner tank 9Y corresponding to a separately provided powder container.
The developer stirring and conveying member 40E mixes and mixes the developer including the replenished toner, and introduces the developer maintained at a predetermined concentration into the space of the developer supplying member 40C.

  In FIG. 2, reference numeral 110 denotes a density sensor, which outputs the result of detection of the toner density in the developer to the control unit based on a change in inductance. In the control unit, when the density is insufficient according to the detection result from the density sensor 110, the toner tank 9Y is rotated to replenish new toner.

  FIG. 3 is a diagram illustrating a configuration of a powder conveyance device for conveying toner from toner tanks 9Y, 9M, 9C, and 9Bk, which are powder containers, to the developing devices 40Y, 40M, 40C, and 40Bk.

  In FIG. 3, the toner discharge ports of the toner tanks 9Y, 9M, 9C, and 9Bk and the developer accommodating portions on the developing devices 40Y, 40M, 40C, and 40Bk side (in this case, the developer stirring and conveying member 40E (see FIG. 2)). Are connected to each other), and conveying pipelines 101Y, 101M, 101C, and 101Bk forming a part of the powder conveying apparatus are respectively connected.

FIG. 4 is a diagram showing a connection structure on the upstream side in the conveyance direction of toner, which is powder, in a conveyance pipeline (for convenience, denoted by reference numeral 101 but denoted by reference numeral 101Y).
In the drawing, the upstream side of the transport direction of the toner in the transport pipeline 101 is located in a front end resin case 9Y1 provided at the front end of the toner tank.
The front end resin case 9Y1 has a toner reservoir 9Y2 that communicates with a toner discharge port (not shown) on the toner tank side, and is a conveying member for delivering toner in the toner reservoir 9Y2. A conveying screw 9Y3 is arranged.

  In FIG. 4, reference numeral 9Y4 is an opening formed in the front end resin case 9Y1, and reference numeral 9Y5 is a toner passage provided in a nozzle (not shown) attached to the front end resin case 9Y1 and communicating with the toner reservoir 9Y2. .

  The conveying screw 9Y3 has a configuration in which a coil 9Y3A is mounted on the circumferential surface of the rotating shaft, and a driven gear G2 that transmits the rotation of the driving gear G1 provided on the driving shaft 9Y6 supported by the tip resin case 9Y1. It is a member that can be rotated by being provided in the shape of a rotation shaft, and the toner in the toner reservoir 9Y2 can be fed out toward the transport pipeline 101 by rotating in conjunction with the rotation of the toner tank 9Y.

A coil spring 102 is disposed in the transport pipeline 101 as a transport means having one longitudinal end connected to the transport screw 9Y3.
The coil spring 102 has an outer diameter in which a gap necessary for rotation between the coil spring 102 and the inner wall surface of the conveyance pipeline is set, and a developing tank on the downstream side in the conveyance direction from the position of the tip resin case 9Y1 on the upstream side in the toner conveyance direction It is arranged over the entire longitudinal direction up to 40A.

The features of the present invention will be described with the above configuration as an object.
The first feature of the present invention is that a relationship is set such that the amount of powder on the downstream side in the toner transport direction, that is, the amount of toner is larger than the amount on the upstream side in the toner transport direction.

  FIG. 5 is a diagram for explaining this configuration. In FIG. 5, the relationship between the above-described powder amount, that is, the toner amount, is as shown in FIGS. 5B and 5C. The opening area at the upstream side of the toner transport direction in 101, that is, the downstream side of the opening direction at the opening position at the position indicated by A in FIG. 5 and the opening area at the position indicated by B in FIG. It is obtained by setting.

In the configuration shown in FIG. 5, the opening on the upstream side in the conveying direction is configured with a circular cross section having a diameter R1, and the downstream opening is set to have the diameter R1 described above for the length of the vertical piece and the length of the horizontal piece R2. It consists of a rectangular cross section.
By making the opening on the downstream side in the transport direction a rectangular cross section, the thickness of the peripheral wall of the transport conduit 101 can be prevented from becoming extremely thin, and the strength of the transport conduit can be secured.

  Since the present embodiment is configured as described above, the amount of toner that moves in the transport pipeline 101 is larger on the downstream side than on the upstream side in the transport direction, and therefore the upstream in the transport direction in the transport pipeline 101Y. Since the toner can easily move from the side, the retention of toner on the upstream side in the transport direction is eliminated, and clogging can be eliminated.

Next, the second feature of the present invention will be described.
A second feature of the present invention is that the above-described powder amount settings on the upstream side and the downstream side in the transport direction are set by a transport screw that is an existing component member.
That is, in FIG. 2, the screw pitch of the conveying screw 9Y3 disposed in the front end resin case 9Y1 on the toner tank 9Y side is reduced as compared with the case where it is used as an existing member.
Thereby, the conveyance amount per rotation of the conveyance screw is reduced.

  In the present embodiment, the amount of toner delivered from the toner tank located upstream in the toner conveyance direction can be made smaller than the conveyance amount by the coil spring 103Y located in the conveyance pipeline 101Y. The toner amount on the downstream side in the transport direction described in the above can be made larger than the toner amount on the upstream side in the transport direction. As a result, the toner easily flows in the transport pipeline, particularly in the upstream in the transport direction, and clogging is eliminated.

Next, the third feature of the present invention will be described.
A third feature of the present invention is that the above-described toner amount relationship is set by the configuration of a coil spring that is an existing component member.
In other words, in the longitudinal direction of the coil spring 103Y disposed in the transport pipeline 101Y, the helical pitch is increased from the upstream side to the downstream side in the toner transport direction.

FIG. 6 is a diagram for explaining the helical pitch of the coil spring 103Y described above.
In the drawing, the helical pitch (L1, L2) of the coil spring 103Y increases from the toner reservoir 9Y2 located on the upstream side in the transport direction to the toner discharge port located on the downstream side in the transport direction (L2> L1). It is related.

In the present embodiment, the amount of conveyance per one rotation of the coil spring 103Y increases on the downstream side in the conveyance direction as it goes from the upstream side to the downstream side in the toner conveyance direction. That is, the amount of movement while scooping with the coil blades during one rotation increases.
As a result, the toner can easily move on the upstream side in the conveyance direction, and clogging can be eliminated.

The following describes the fourth feature of the present invention.
The fourth feature of the present invention is that the helical pitch of the coil spring 103Y is the same as that when the coil spring 103Y is used as an existing welfare member, and the toner that is conveyed is repelled and loosened on the downstream side in the toner conveying direction. The elastic member that can be used is arranged.

  In other words, when the toner conveyed by the coil spring 103Y rotates in conjunction with the rotation of the coil spring 103Y, the elastic member causes a collision with the stationary elastic member in the shearing direction or the thickness direction of the elastic member. It will be loosened by being played. As a result, the toner can easily fall to the toner discharge port side, thereby promoting the movement of the toner in the conveyance pipeline. As a result, the toner can easily flow into the conveyance pipeline on the upstream side in the conveyance direction.

FIG. 7 shows a configuration for this purpose.
In FIG. 7, an elastic member 200 made of a single member having a thickness of about 0.15 mm is fixed in the vicinity of the toner discharge port on the downstream side in the toner conveyance direction in the conveyance pipeline 101Y. The elastic member 200 is disposed at the diameter position with almost no gap between the inner surface of the transport pipeline 101Y.

  In the present embodiment, the toner conveyed to the downstream side in the conveyance direction is easily bounced and loosened by the elastic member 200, so that it easily flows to the discharge port, and the toner fluidity on the downstream side in the conveyance direction in the conveyance pipeline 101Y is good. As a result, the flow of toner on the upstream side in the conveyance direction is improved, and stagnation and clogging are prevented.

In the above embodiments, the flow state of the toner, which is powder, on the downstream side in the conveyance direction is improved. As a result, the flow of toner in the entire area of the conveyance pipeline 101Y is improved, and the toner easily flows on the upstream side in the conveyance direction. As a result, the conveyance abnormality can be resolved, an increase in the load on the drive member and insufficient conveyance of the powder can be prevented, and further, the density reduction of the image can be prevented.
In the above-described embodiment, toner is used as the powder. However, the present invention is not limited to this as long as it is a substance included in the concept of powder.

9Y Toner tank 9Y1 Tip resin case 9Y2 Toner reservoir 9Y3 Conveying screw 100 Image forming apparatus 101Y Conveying line 102 Coil spring A Toner amount on the upstream side in the toner conveying direction B Toner amount on the downstream side in the toner conveying direction R1 One of the openings Diameter R2 set to one Length used for the cross-sectional area of the rectangular cross-sectional opening

JP-A-2005-24665

Claims (9)

A powder conveying apparatus provided with a powder conveying path communicating with the upstream side and the downstream side between the upstream side and the downstream side in the powder conveying direction,
A powder conveying apparatus characterized in that a relationship is set such that the amount of powder per unit time on the downstream side in the conveying direction is larger than the amount of powder introduced per unit time on the upstream side in the conveying direction.   The setting of the powder amount on the upstream side and the downstream side in the transport direction makes the cross-sectional area of the powder discharge part located on the downstream side in the transport direction larger than the cross-sectional area of the powder introduction part located on the upstream side in the transport direction The powder conveying apparatus according to claim 1, wherein the powder conveying apparatus is set as described above.   The relation setting of the powder amount between the upstream side and the downstream side in the transport direction is set by making the transport amount by the transport member on the upstream side in the transport direction smaller than the transport amount by the transport means on the downstream side in the transport direction. The powder conveying apparatus according to claim 1, wherein   The screw member is used as the conveying member on the upstream side in the conveying direction, the coil spring is used as the conveying member on the downstream side in the conveying direction, and the screw pitch of the screw member is set smaller than the helical pitch of the coil spring. The powder conveyance device according to claim 3, wherein the powder conveyance device is provided.   One of the Claims 1 thru | or 3 by which the setting of the relationship of the powder amount of the said conveyance direction upstream and downstream is set by the coil spring which became large helical pitch as it was sufficient in the conveyance direction downstream. The powder conveying apparatus as described in one.   6. An elastic member capable of repelling the conveyed powder is disposed in the vicinity of the powder discharge portion located on the downstream side in the conveying direction. The powder conveying apparatus described in 1. A developing device used for supplying a developer containing powder to an electrostatic latent image formed on an electrostatic latent image carrier to process a visible image,
A toner tank as a powder container is connected to the developer supply section separately from the developer supply section, and the connection section is connected to the developer supply section. A developing device characterized in that the powder conveying device described in claim 1 is used. A process cartridge capable of accommodating at least a latent image carrier and a developing device,
7. A process cartridge, wherein the developing device is equipped with the powder conveying device according to claim 1. An image forming apparatus including an image forming station capable of forming an image of at least one color,
9. The image forming apparatus according to claim 8, wherein the image forming station uses a process cartridge according to claim 8.

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