JP2002333764A - Developing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the blowoff of toner and the blocking thereof in a developing unit caused by the excessive replenishment of the developing unit with the toner from a toner replenishing container in the developing device of an image forming device. SOLUTION: Toner passing holes 42b and 63a are formed on the developing unit 60 and a toner cartridge 62 one by one, and partition plates a1 and a2 respectively dividing the toner passing holes up and down are provided so that a toner replenishing port b1 and a toner restoring port c1 are formed in the toner passing hole 42b of the developing unit and a toner replenishing port b2 and a toner restoring port c2 are formed in the toner passing hole 63a of the toner cartridge by the partition plates. Then, the toner passing holes are coupled and the developing unit is replenished with the toner from the toner cartridge through the toner replenishing ports. When a developing chamber is full of the toner, the toner is restored to the toner cartridge from the developing unit through the toner restoring ports on the contrary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a printer, a facsimile, and a multifunction peripheral thereof.
The present invention relates to an image forming apparatus that records an image on a sheet such as an OHP film. In particular, the present invention relates to an electrophotographic image forming apparatus that transfers an image formed on an image carrier by repeating charging, writing, development, transfer, cleaning, and the like, and records the image on a sheet. And, in such an electrophotographic image forming apparatus, using a one-component developer consisting only of toner or a two-component developer consisting of toner and carrier,
The present invention relates to a developing device that develops an electrostatic latent image formed on a surface of an image carrier.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, an electrostatic latent image is formed on an image carrier by charging and writing, and toner is adhered by a developing device to develop the electrostatic latent image. Since the developing device consumes toner as it is used, a replenishing toner container such as a toner bottle or a toner cartridge is provided, and new toner is supplied from the replenishing toner container.

For example, as shown in FIG. 7, a developing device includes a developing device 1 and a toner cartridge 2 as a replenishing toner container, and a toner replenishing port 3 of the toner cartridge 2 is connected to a toner replenishing port 4 of the developing device 1. connect. The agitator 5 which is a toner stirring member in the toner cartridge 2
6 to rotate the toner supply port 3
4, toner was supplied from the toner cartridge 2 to the developing device 1.

[0004] Reference numeral 7 in FIG. 7 denotes a toner paddle as a toner stirring member of the developing device 1. Reference numeral 8 denotes a developer carrier for developing an electrostatic latent image on the belt-shaped image carrier 9 by attaching toner.

[0005]

However, in such a developing device, there is a possibility that toner is blown out or blocked in the developing device 1 due to excessive toner supply from the toner cartridge 2 to the developing device 1. Was.

In particular, regardless of the amount of toner in the developing device 1,
Such a problem is sufficiently caused in a quantitative replenishment type developing device that constantly replenishes toner from the toner cartridge 2 to the developing device 1 at the time of image recording.

Accordingly, a first object of the present invention is to provide a developing device of such an image forming apparatus which is capable of preventing toner from being blown out or blocked in the developing device due to excessive toner replenishment from a replenishing toner container to the developing device. To avoid.

A second object of the present invention is to facilitate connection of a replenishing toner container to a developing device in such a developing device and to easily prevent toner leakage from the connecting portion.

A third object of the present invention is to reliably supply and return the toner in such a developing device.

A fourth object of the present invention is to clearly distinguish between toner replenishment and toner return in such a developing device and to surely carry out them.

A fifth object of the present invention is to stabilize toner supply and toner return by making toner flow smooth.

A sixth object of the present invention is to provide an image forming apparatus provided with a developing device which achieves the above object.

[0013]

According to the present invention, in order to achieve the first object, a toner supply port of a supply toner container is connected to a toner supply port of a developing device.
In the developing device of the image forming apparatus for supplying toner from the replenishing toner container to the developing device through the toner replenishing port, a toner return port for returning the toner from the developing device to the replenishing toner container is formed in the developing device and the replenishing toner container. It is characterized by that.

According to a second aspect of the present invention, in order to achieve the second object, in the developing apparatus according to the first aspect, one toner passage hole is formed in each of the developing device and the supply toner container. And a partition plate for dividing the toner passage holes into upper and lower portions, and a toner supply port and a toner return port are formed in each of the toner passage holes by the partition plates.

According to a third aspect of the present invention, in order to achieve the third object, in the developing device according to the second aspect of the present invention, the partition plates are respectively projected inward to stir the toner in the developing device and the replenishment toner container. It is inserted into the rotation trajectory of the member,
It is characterized by the following.

According to a fourth aspect of the present invention, in order to achieve the fourth object, in the developing device according to the third aspect, the leading end of the partition plate of the developing device is bent and the developing device is passed through the toner supply port. A toner return preventing portion for preventing toner from returning to the supply toner container is formed.

According to a fifth aspect of the present invention, in order to achieve the fifth object, in the developing device according to the first, second, third, or fourth aspect, the toner of the developing device is supplied from a toner supply port of a supply toner container. The supply port is made larger, and the toner return port of the supply toner container is formed larger than the toner return port of the developing device.

According to a sixth aspect of the present invention, there is provided an image forming apparatus for achieving the sixth object.
A developing device according to 3, 4, or 5 is provided.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall schematic configuration of a color laser printer which is an example of an image forming apparatus.

An image carrier unit 10 is provided substantially in the center of the printer main body A of the illustrated color laser printer. The image carrier unit 10 is provided with an endless belt-shaped image carrier 12 by being wrapped around a plurality of rollers 11. An organic photosensitive layer is formed on the surface of the image carrier 12.

Around the image carrier unit 10, a charging unit 14, a writing unit 15, a multi-stage developing unit 16, an intermediate transfer unit 17, a cleaning unit 1
8 and the like.

The charging unit 14 uniformly charges the surface of the image carrier 12 by applying a high voltage.

The writing unit 15 emits laser light from a laser diode (not shown) based on, for example, a color image signal from a computer, and outputs the laser light via a polygon mirror 20, an f / θ lens 21, a plurality of reflection mirrors 22, and the like. Then, writing corresponding to the image signals of black, cyan, magenta, and yellow is performed, and an electrostatic latent image is formed on the image carrier 12.

The multi-stage developing unit 16 is, as shown in FIG.
As shown in FIG. 2, each of the developing devices 24 containing black, cyan, magenta, or yellow developer in order from the bottom.
K, 24C, 24M, and 24Y are detachably provided in multiple stages. Then, each developing device 24 is selectively brought close to the image carrier 12, and roller-shaped developer carriers 25 K, 25 C, 25 M, and 25 Y provided in each developing device 24 are brought into contact with or close to the image carrier 12. .

The intermediate transfer unit 17 is wound around a plurality of rollers 27 as shown in FIG.
8 And around that, the sheet transport path 3
An intermediate transfer roller 31 is provided between the intermediate transfer belt 28 and a cleaning device 32 for the intermediate transfer belt 28.

Cleaning unit 18 for image carrier 12
Presses the cleaning blade against the image carrier 12. Although not shown, the cleaning device 32 for the intermediate transfer belt 28 similarly has
The cleaning blade is pressed against the surface.

By the way, a paper feed cassette 34 is attached to the bottom of the printer apparatus main body A of this laser printer so that it can be freely taken in and out. The sheet in the paper feed cassette 34 is fed out by the rotation of the paper feed roller 35, sent out to the sheet transport path 30, transported by the transport roller 36, and timed by the registration roller 37 between the intermediate transfer belt 28 and the intermediate transfer roller 31. Send to.

A discharge roller 39 is provided downstream of the sheet conveying path 30 following the fixing unit 38. Further, on the main body A of the printer, there is provided a paper discharge stacking section 40 for stacking printed sheets face down.

When recording is performed by the laser printer, the rollers 11 and 27 are rotated to convey the image carrier 12 and the intermediate transfer belt 28 in the directions indicated by arrows in FIG. Then, the sheet is fed between the intermediate transfer belt 28 and the intermediate transfer roller 31 through the sheet conveyance path 30.

On the other hand, the surface of the image carrier 12 is charged by the charging unit 14, writing is performed by the writing unit 15, and an electrostatic latent image is sequentially formed on the image carrier 12 for each color. Next, the toner is electrostatically attached by the multi-stage developing unit 16 and is visualized for each color. The respective color images are transferred to the intermediate transfer belt 28.
The image is transferred onto each color, and four colors are combined to form a color image.

The color image formed on the intermediate transfer belt 28 is transferred to a sheet by the intermediate transfer roller 31. After fixing the transferred image on the sheet after the image transfer, the sheet is discharged onto a discharge stack unit 40 by a discharge roller 39 and stacked there.

After image transfer, the image carrier 12 is removed by a cleaning blade of a cleaning unit 18 to remove transfer residual toner, and is ready for the next image formation. Also, the intermediate transfer belt 28 after the image transfer is prepared for the next image formation by removing the transfer residual toner by the cleaning blade of the cleaning device 32.

Each developing device 24 includes a developing device 60 and a toner cartridge 62, as shown in FIG.
And The developing device 60 has improved durability and can be used repeatedly by replacing the toner cartridge with a new one even when the toner in the toner cartridge 62 runs out.

The developing device 60 forms a developing chamber 41 and a toner cartridge storage chamber 43 in a developing case 42.
In the developing chamber 41, a roller-shaped developer carrier 25 is provided. The developer carrier 25 is connected to the developing opening 4 of the developing case 42.
It faces the image carrier 12 through 2a and rotates in the same direction as the image carrier 12 at the facing position. A roller-shaped developer regulating member 44 is pressed against the developer carrier 25.

A developer regulating member 44 is also provided in the developing chamber 41, and as shown in FIG. 4, the shaft 45 is supported by the developing case 42 via a bearing 46, and the bearing 46 is urged by an urging member 47. And is pressed against the developer carrier 25. Then, at the pressing position, the developer carrier 25 rotates in the counter direction with respect to the developer carrier 25.

As shown in FIG. 3, the tip of a scraping member 48 is pressed against the developer regulating member 44. The scraping member 48 scrapes off the developer adhering to the surface of the developer regulating member 44.

A roller-shaped developer supply member 50 is brought into contact with the developer carrier 25 with a predetermined nip.
The developer supply member 50 is also provided in the development chamber 41 and is made of a foam material 51 such as polyurethane, silicon, EPDM, or polycarbonate, and a metal core 52. The contact position may be any direction, but in the illustrated example, it rotates in the counter direction with a linear velocity difference relative to the developer carrier 25. A partition 54 is provided below the developer supply member 50.

On the back side (left side in the figure) of the developing chamber 41,
A toner paddle 56 is provided as a toner stirring member, and stores a developer. The toner paddle 56 has a plurality of blades 56a, such as a mylar, and rotates counterclockwise in the drawing in the illustrated example.

The boundary 57 between the developing chamber 41 and the toner cartridge storage chamber 43 of the developing case 42
One toner passage hole 42b is opened.

On the other hand, in the toner cartridge storage chamber 43, the toner cartridge 62 is detachably pulled out from the near side.
To store. The toner cartridge 62 includes two agitators 64 on the left and right sides as a toner stirring member in a cartridge case 63, and stores black, cyan, magenta, and yellow toners, respectively. Agitator 6
4 has a plurality of blades 64a made of a mylar or the like, and may rotate in any direction.

The cartridge case 63 has one toner passage hole 63a. When the toner cartridge 62 is mounted in the toner cartridge storage chamber 43, the toner passage hole 63a faces the toner passage hole 42b of the boundary wall 57 described above. At this time, a seal member 65 is interposed between the peripheral edges of the toner passage holes 63a and the toner passage holes 42b.

At the time of image recording, the toner paddle 5
At 6, the developer is conveyed while being stirred, pumped up on the partition table 54, and adheres to the developer supply member 50. While rotating, the developer supply member 50 rubs the developer, preliminarily triboelectrically charges, adheres it by Coulomb force, and supplies it to the developer carrier 25.

The developer carrier 25 carries the toner while rotating, and transfers the carried toner to the developer regulating member 44.
And the developer regulating member 4
4 to make it thinner. Then, the thinned toner is adhered to the image carrier 12 to visualize the latent image on the image carrier 12.

In the illustrated example, a belt-shaped image carrier 12 is used. However, if the surface hardness of the developer carrier 25 is kept low, a drum-shaped image carrier 12 can be used. .

As shown in detail in FIG. 5, a partition plate a1 is formed in the toner passage hole 42b of the developing device 60 so as to be integrally formed with the developing case 42 and divides the toner passage hole 42b into upper and lower portions. A toner supply port b1 is provided below the plate a1.
To form a toner return port c1 on the upper side. Then, the partition plate a1 projects inward and enters the rotation locus of the toner paddle 56, and bends the tip downward to form a toner return blocking portion d at the tip.

On the other hand, in the toner passage hole 63a of the toner cartridge 62, a partition plate a formed integrally with the cartridge case 63 and dividing the toner passage hole 63a into upper and lower parts.
2, a toner supply port b2 is formed below the partition plate a2, and a toner return port c2 is formed above the partition plate a2. And the partition plate a2
Protrudes inward and enters the rotation locus of the agitator 64.

At the time of image recording, the agitator 64 is rotated to agitate and transport the toner, and the toner is supplied from the toner cartridge 62 to the developing device 60 through the toner supply ports b2 and b1. At this time, the blade 64a of the agitator 64 is brought into contact with the partition plate a2 to reliably supply the toner to the toner supply port b2.
Let's lead to.

When the inside of the developing chamber 41 is full of toner, the toner is returned from the developing device 60 to the toner cartridge 62 through the toner return ports c1 and c2 by the rotation of the toner paddle 56. At this time, the blades 56a of the toner paddle 56 are brought into contact with the partition plate a1, so that the toner is reliably guided into the toner return port c1.

At this time, the toner is prevented from returning from the developing device 60 to the toner cartridge 62 through the toner supply ports b1 and b2 by being blocked by the toner return blocking portion d. As a result, toner supply and toner return can be clearly distinguished and both can be reliably performed.

By doing so, it is possible to avoid the occurrence of toner blowing or blocking in the developing device 60 due to excessive toner supply from the toner cartridge 62 to the developing device 60.

In the above-described example, the opening area of the toner supply port b1 provided in the developing device 60 is made substantially equal to the opening area of the toner supply port b2 provided in the toner cartridge 62, and the toner return port c1 provided in the developing device 60 is provided. Opening area and toner return port c provided in toner cartridge 62
The opening areas of No. 2 were made substantially equal.

However, as shown in FIG. 6, the opening area of the toner supply port b1 provided in the developing device 60 is larger than the opening area of the toner supply port b2 provided in the toner cartridge 62. The toner return port c2 provided in the toner cartridge 62 from the opening area of c1
May be formed to have a larger opening area.

This makes it possible to smooth the flow of toner and stabilize toner supply and toner return. In FIG. 6, the reference numerals used for the corresponding parts in FIG. 5 are used as they are.

In the above-described example, the developing device 60 and the toner cartridge 62 each have one toner passage hole 42 b.
3a, and partition plates a1 and a2 for vertically dividing the toner passage holes 42b and 63a, respectively, are provided, and the toner passage holes 42b and 63 are formed by the partition plates a1 and a2.
a, toner supply ports b1, b2 and toner return ports c1, c2
And formed.

Thus, when the toner cartridge 62 is connected to the developing device 60, one toner passage hole 42b
It is only necessary to match 63a, and it is only necessary to seal around 63a, so that toner leakage from the connecting portion can be easily prevented.

Of course, one toner passage hole 42b is not partitioned to form a toner supply port b1 and a toner return port c1. Instead, one toner passage hole 63a is partitioned to form a toner supply port b2 and a toner return port c2. Instead of forming the toner supply port b1 and the toner return port c1 separately from each other in the developing device 60, the toner supply port b2 and the toner return port c2 may be provided in the toner cartridge 62. They may be separately provided separately.

In the above-described example, the case where the box-type toner cartridge 62 is used as the supply toner container has been described. However, the supply toner container is not limited to a box shape, and may be, for example, a bottle-shaped toner bottle.

Further, in the above-described example, the case where the present invention is applied to a color laser printer which is an example of an image forming apparatus has been described. However, the present invention is not limited to a color printer, is not limited to a laser printer, and is limited to a printer. However, the present invention can be naturally applied to other image forming apparatuses.

[0059]

As described above, according to the first aspect of the present invention, the toner return port for returning the toner from the developing device to the supply toner container is formed in the development device and the supply toner container. When full, toner is returned from the developing unit to the replenishment toner container through the toner return port, thereby avoiding toner blowing and blocking at the developing unit due to excessive toner supply from the replenishment toner container to the developing unit. can do.

According to the present invention, one toner passage hole is formed in each of the developing device and the supply toner container,
A partition plate for dividing the toner passage holes into upper and lower portions is provided, and a toner supply port and a toner return port are formed in each of the toner passage holes by the partition plates. Since only one toner passage hole needs to be aligned and only the periphery thereof needs to be sealed, leakage of toner from the connection portion can be easily prevented.

According to the third aspect of the present invention, the partition plates protrude inwardly and enter the rotation locus of the toner stirring member of the developing device and the supply toner container. The toner can be reliably guided into the toner supply port by contacting the plate, and the toner can be reliably guided into the toner return port by contacting the toner stirring member of the developing device to the partition plate.

According to the fourth aspect of the present invention, the tip of the partition plate of the developing device is bent to form a toner return preventing portion for preventing the toner from returning from the developing device to the supply toner container through the toner supply port. Therefore, the toner is prevented from returning from the developing device to the replenishing toner container through the toner replenishing port by being blocked by the toner return preventing portion, so that toner replenishment and toner return can be clearly distinguished and both can be reliably performed.

According to the fifth aspect of the invention, the toner supply port of the developing device is larger than the toner supply port of the supply toner container, and the toner return port of the supply toner container is larger than the toner return port of the developing device. Since the toner is formed, the flow of the toner can be made smooth and the toner replenishment and the toner return can be stabilized.

According to the invention of claim 6, according to claim 1,
Since the image forming apparatus includes the developing device described in 2, 3, 4, or 5, it is possible to provide an image forming apparatus including the developing device having the above-described effects.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram of a color laser printer as an example of an image forming apparatus.

FIG. 2 is a schematic configuration diagram of a multi-stage developing unit provided in the color laser printer.

FIG. 3 is a schematic configuration diagram of one developing device used in the multi-stage developing unit.

FIG. 4 is a diagram illustrating a state in which a developer regulating member is pressed against a developer carrier in the developing device.

FIG. 5 is a partially enlarged view near a toner passage hole of the developing device.

FIG. 6 is a partially enlarged view of the vicinity of a toner passage hole of another example.

FIG. 7 is a schematic longitudinal sectional view of a conventional developing device.

[Explanation of symbols]

Reference Signs List 16 Multi-stage developing unit 24 Developing device 41 Developing chamber 42 Developing case 42b Toner passing hole of developing device 56 Toner paddle (toner stirring member of developing device) 56a Toner paddle blade 60 Developing device 62 Toner cartridge (supplemented toner container) 63 Cartridge case 63a Toner passage hole of toner cartridge 64 Agitator (toner stirring member of toner cartridge) 64a Blade of agitator a1 Partition plate of developer unit a2 Partition plate of toner cartridge b1 Toner supply port of developer unit b2 Toner supply port of toner cartridge c1 Developing unit C2 toner return port of toner cartridge d toner return blocking section

Claims (6)

[Claims] 1. A developing device of an image forming apparatus, wherein a toner supply port of a supply toner container is connected to a toner supply port of a developing device, and toner is supplied from the supply toner container to the developing device through the toner supply ports. Conversely, a developing device, wherein a toner return port for returning toner from the developing device to the supply toner container is formed in the development device and the supply toner container. 2. A toner passing hole is formed in each of the developing device and the replenishing toner container, and a partition plate for dividing the toner passing hole into upper and lower portions is provided. The developing device according to claim 1, wherein the toner supply port and the toner return port are formed in the toner supply port. 3. The developing device according to claim 2, wherein each of the partition plates protrudes inward so as to enter a rotation locus of a toner stirring member of the developing unit and the supply toner container. 4. A toner return preventing portion for bending a tip of the partition plate of the developing device to prevent toner from returning from the developing device to the replenishing toner container through the toner replenishing port. The developing device according to claim 3. 5. The toner supply port of the developing device is formed larger than the toner supply port of the supply toner container, and the toner return port of the supply toner container is formed larger than the toner return port of the developer device. The developing device according to claim 1, 2, 3, or 4. 6. An image forming apparatus comprising the developing device according to claim 1, 2, 3, 4, or 5.