JP3498005B2 - Toner supply device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner replenishing device for replenishing a developing device in an image forming apparatus such as a copying machine, a printer or a facsimile machine.

[0002]

2. Description of the Related Art An image forming apparatus for forming an image using a two-component developer or a one-component developer comprising a toner and a magnetic carrier has an empty state when the apparatus is installed. When toner is filled in the toner replenishing device, or as a result of repeating the image forming work,
If the toner in the toner replenishing device is exhausted and it is determined that the amount of toner remaining in the toner hopper is almost zero, a specialist engineer or user should use the toner bottle or toner cartridge. Then, a method of replenishing a toner replenished in a predetermined amount in these containers to a toner replenishing device in accordance with a predetermined procedure has become the mainstream.

Here, in the image forming apparatus, a toner having a small particle diameter is frequently used in response to the recent demand for high image quality, and a toner containing various additives is used for the purpose of improving fluidity and charging performance. It is used. Further, before replenishing toner to the toner hopper of the image forming apparatus via the toner bottle or toner cartridge filled with toner, the toner bottle or toner cartridge is shaken several times and then mounted at a predetermined position of the toner replenishing device. As described above, it is described and instructed in the instruction manual of the image forming apparatus.

However, in addition to the fact that the toner has a high charging property even when it is shaken several times at most and the fluidity is improved, when the toner having a small particle size is used originally. When the toner bottle or toner cartridge is attached to the toner replenishing device, the toner behaves almost like a liquid, and the toner leaks from the opening of the toner hopper, or it passes through the opening of the toner hopper at once. Excess toner may flow into the developing device.

In the case of a developing device which is relatively large and accommodates a large amount of developer, even if a large amount of toner flows in, a large amount of developer is retained and the stirring ability is large, so that this adverse effect is suppressed. , It is possible to absorb. However, in a relatively small developing device, if a large amount of toner concentrates at one time during toner replenishment, a serious problem will occur.

That is, in a small developing device, since the absolute amount of the developer that can be stored in the developing device is small, the inside of the developing device is temporarily in an over toner state, and the developing device is agitated with respect to the excessive toner amount. The performance cannot be followed, and the problems such as poor stirring of the developer, toner deterioration, image quality deterioration such as fog, and contamination inside the machine due to toner ejection from the opening of the developing device are likely to occur.

Here, in a developing cartridge in which a toner replenishing device and a developing device are integrated, in order to prevent toner from flowing into the developing device at the time of transportation, cartridge replacement, etc., for example, Japanese Patent Laid-Open No. 5-80653. Japanese Patent Laid-Open No. 6-
As described in Japanese Patent Publication No. 95506, as shown in FIGS. 10 and 11, it is described that a seal member 5 for sealing between the opening 3 communicating with the toner hopper 1 to the developing device 2 and the toner supply roller 4 is provided. The seal member 5 is wound by the rotation of the stirring member 6 in the toner hopper 1 or accommodated in the guide member 8 as the elastic member 7 contracts.

As described above, when the seal member 5 is provided in the toner hopper 1, the structure is simplified, but a large force is required to remove the seal member 5 from the toner replenishing roller 4 when starting the toner replenishment. , Seal member 5 even after extraction
Since the front end portion of the sheet rubs against the inner wall of the toner hopper 1, there arises a problem that the driving force of the apparatus is increased and the toner characteristics are deteriorated due to sliding friction.

When the toner replenishing device and the developing device cannot be integrated due to the structure of the image forming apparatus, the toner replenishing device 10 and the developing device 11 are arranged independently as shown in FIGS. A cylinder 13 is projectingly provided on the bottom of the developing device 11, and the cylinder 13 is extended to above the developing device 11. The toner supply port 14 that is an opening formed in the cylinder 13 communicates with an opening 16 formed on the upper surface of the developing tank 15 of the developing device 11. Toner hopper 12
A screw conveyor 19 having a spiral blade 18 formed along the conveyor shaft 17 is provided at the bottom of the screw conveyor 19, and one end of the screw conveyor 19 is housed in the cylinder 13. The toner stored in the toner hopper 12 is conveyed toward the toner supply port 14 by the rotation of the screw conveying body 19, is discharged from here, and is supplied to the developing device 11. In the figure, 20 is a photosensitive drum, 21 is a developing roller, 22 is a stirring roller, and 23 is a conveying roller.

When a toner having a high chargeability, a low density and a small particle diameter is used in the apparatus having the above-mentioned structure, such a toner is shaken a toner bottle or a toner cartridge several times before the toner is replenished. Liquefy easily and behave like a liquid, so that excessive toner flows into the developing device 11 from the toner supply port 14 due to a sudden impact or vibration when replenishing the toner.

In order to prevent the unnecessary inflow of toner, the toner replenishing device 10 is provided with a shutter mechanism for closing the toner supply port 14. In the shutter mechanism, as shown in FIGS. 14 and 15, the cylinder 13 of the toner hopper 12 is
An outer cylinder 24 is provided so as to cover the outer cylinder 24, and an opening 25 is appropriately provided on the peripheral surface of the outer cylinder 24. The outer cylinder 24 is a cylinder so that the opening 25 and the toner supply port 14 of the cylinder 13 are aligned with each other. By rotating around 13 or sliding along the cylinder 13 in the transport axis direction, the toner supply port 1
4 is opened and closed.

When the toner in the toner hopper 12 is in a good fluidity, it is easily affected by vibrations and impacts. Therefore, the shutter mechanism prevents the toner from rapidly flowing into the developing device 11. Toner supply port 14
Is closed, the connection work between the toner hopper 12 and the developing device 11 is completed, and when these start the image forming work, the opening 25 of the outer cylinder 24 is aligned with the toner supply port 14 in accordance with the toner replenishment request. To the toner supply port 14
Open up.

In such a shutter mechanism, whether the outer cylinder is manually moved or a spring or a motor is used, the number of parts is increased, and the number of parts of the apparatus increases. The structure is complicated and large, which is disadvantageous in reducing the size of the entire apparatus. Especially, it is not preferable for application to personal machines and low-end machines.

In view of the above, it is an object of the present invention to provide a toner replenishing device capable of preventing the toner from flowing out of the toner hopper with a simple structure even when using a toner having good fluidity.

[0015]

In order to prevent the toner in the toner hopper from leaking out from the toner supply port formed at the bottom of the toner hopper, a shield portion covering the toner supply port is provided. It is provided to try to block the inside of the toner hopper from the toner supply port. As the shield part, a part of the screw carrier provided at the bottom of the toner hopper is used so that it is not necessary to add another member. That is, the shield portion is a rib integrally provided on the conveying shaft or the spiral blade that constitutes the screw conveying body. Specifically, in a region where the screw transport body faces the toner supply port, a rib is provided so as to project from the transport shaft in the radial direction to form a shield part that blocks a space communicating with the toner supply port.

With this configuration, when the toner having good fluidity is replenished in the toner hopper, since the shield portion covers the toner supply port, the toner does not enter the toner supply port and prevents the toner from flowing out. be able to.
Then, when the toner is supplied to the developing device, when the screw carrier is rotated, the shield part is also rotated and the toner supply port appears, so that the toner carried by the screw carrier is discharged from the toner supply port.

By the way, when toner is supplied from the toner hopper to the developing device while the toner replenishing device is attached to the developing device, the shield portion also rotates. Therefore, when the toner replenishing operation is completed, the toner supply port is shielded by the shield portion. It will not be done. Therefore, when the toner is not being supplied to the developing device, the screw feed member is controlled to be rotated so that the shield portion shields the toner supply port until the shield portion faces the toner supply port. Therefore, the toner supply port is shielded even when toner is replenished in the toner hopper or when vibration is applied.
It is possible to prevent the toner from leaking from the toner hopper.

Here, in order to further enhance the shield effect, it is only necessary to close all voids leading to the toner supply port. For example, if the rib is connected to a spiral blade or a disk or rib protruding in the circumferential direction, the toner can be prevented from flowing in the axial direction. Further, a seal member is provided for the gap between the bottom of the toner hopper and the rib. As the seal member, the developer may be magnetically or electrostatically adsorbed to the ribs, and a wall is formed by the developer to close the gap and exert a shield effect. Where 2
In the case of the component developer, the developer in the developing device is magnetically attracted through the toner supply port to form a seal member. In the case of a one-component developer, the magnetic toner in the toner hopper is magnetically attracted to form a seal member. The charged toner may be adsorbed electrostatically. Alternatively, a sealing member may be provided so as to contact the bottom of the toner hopper to close the gap.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A toner replenishing device 10 according to this embodiment is detachably mounted on a developing device 11 as shown in FIG. 1, and is different from the conventional one shown in FIGS. Since the basic configuration is the same, detailed description will be omitted. Therefore, a characteristic configuration of the toner supply device 10 of the present embodiment will be described. In the toner replenishing device 10, the screw conveying body 19 is provided with a shield portion 30 that blocks the interior of the toner hopper 12 and the toner supply port 14 to prevent toner leakage from the toner supply port 14.

The screw carrier 19 has a spiral shaft 18 formed on the carrier shaft 17, and is integrally manufactured by resin molding. One side of the screw conveying body 19 is housed in a cylinder 13 protruding from the toner hopper 12, and one side of the conveying shaft 17 is rotatably supported by a side wall of the cylinder 13.
The other side is rotatably supported on the side wall of the toner hopper 12. The transport shaft 17 is connected to a motor via a transmission mechanism such as a gear, and the screw transport body 19 is drive-controlled by a control device provided in the image forming apparatus.

Then, as shown in FIGS.
The spiral blade 18 is not formed in the area of 7 facing the toner supply port 14, and the shield portion 30 is provided there. The shield part 30 is composed of ribs 31 radially protruding from the transport shaft 17 in a radial direction. Rib 31
Are integrally formed on the transport shaft 17 in two rows in parallel along the axial direction and at a constant angle θ in the circumferential direction. Two
The central angle θ formed by one rib 31 is set so that the distance between the tips of both ribs 31 is larger than the circumferential length of the toner supply port 14, and at least one rib 31 has an axial length. The length is larger than the axial length of the toner supply port 14. At this time, a resin molded product is often used as the screw carrier 19, and a 4-way slide mold structure that is advantageous in terms of cost is used. (On the contrary, in order to express the minimum screw shape, it is necessary to make a 4-way slide.) In this case, it is preferable to set the central angle θ of the rib 31 to 90 degrees, which makes the rib 31 easy and inexpensive. Can be formed.

As shown in FIG. 4 (a), the two ribs 31 have spiral blades 18 on the other side communicating with the toner hopper 12.
And the one side facing the side wall of the cylinder 13 is connected to
It is connected to the disk 32 formed in the. Therefore,
A space surrounded by the two ribs 31, the spiral blade 18 and the disc 32 is formed, and the size of this space is larger than the size of the toner supply port 14 so that the toner supply port 14 can be completely covered. . Here, as shown in FIG. 4B, the two ribs 31 are not connected to the spiral blade 18,
If the ends of both ribs 31 are open, the arrow C
There is a case where toner flows along with the toner, and the toner may flow out. As shown in FIG.
Or by connecting to a disc,
The toner outflow along the arrow C is prevented by the spiral blade 18. In this way, the end portions of the ribs 31, especially the toner hopper 1
It is desirable that the end on the second side is connected to the spiral blade 18 or the disc and is closed. Even if the end of the rib 31 is not connected to the spiral blade 18 or the like, the end of the rib 31 is opposed to the spiral blade 18 and the position where the rib 31 is formed is reduced so that the gap becomes smaller. It should be set appropriately. Alternatively, the other end of the rib 31 may be bent in the circumferential direction. That is, in order to prevent the toner from flowing in the axial direction, the spiral blade 18 or the disk is used, or the rib 31 is used.
The shape of

Then, the spiral blade 1 of the screw carrier 19
A gap L is formed between the radial tip of 8 and the inner surface of the cylinder 13 to prevent the spiral blade 18 from coming into contact with each other when it rotates, thereby reducing the rotational load. Therefore, the rib 31 has the same height as the spiral blade 18, and a gap L is similarly formed between the tip of the rib 31 and the cylinder 13. In order to prevent the toner from flowing out from the space L, a seal member is provided at least near the tip of the rib 31.

A magnet 33 is used as the seal member and is attached near the tip of the rib 31 without contacting the inner surface of the cylinder 13. Here, it is desirable that the magnets 33 are provided radially, and a plurality of rod-shaped magnets 33 are arranged along the ribs 31 and bonded to the ribs 31. The magnetic force direction of the magnet 33 coincides with the radial direction, and the magnetic force causes the developer in the developing tank 15 to be adsorbed from the opening 16 of the developing tank 15 communicating with the toner supply port 14. And a magnetic shield is formed between the inner surface of the cylinder 13 and
The magnetic shield prevents the toner from passing through the gap L. Therefore, the rib 31 blocks the toner flow in the arrow A along the circumferential direction, and the seal member blocks the toner flow in the arrow B through the gap,
Since the toner cannot reach the toner supply port 14, the toner can be prevented from flowing out.

The two-component developer toner used in the developing device 11 has a high charging property, a low density and a small particle size. Specifically, the charging amount is 40 μc / g or more, The average density is 0.3 g / cm ³ or less and the average toner particle size is less than 7 μm. The gap L is set to a size 20 to 100 times the toner particle size. If the gap L is smaller than this, the conveyed toner is solidified and becomes resistance, and the screw conveying body 19 cannot rotate smoothly. If the gap L is larger than this, the screw L rotates smoothly, but the gap L
The amount of toner that can pass through is increased and the magnetic shield effect is diminished. With respect to such a gap L, the magnetic force of the magnet 33 is 600 to 9 so as not to increase the rotational load of the screw carrier 19 while having an appropriate magnetic shield effect.
It is adjusted to 00 Gauss, and this magnet 33
of mg / mm ² ~5mg / mm ² of the developer can be adsorbed. That is, when the magnetic force is weaker than this, a sufficient magnetic shield effect cannot be obtained, and when the magnetic force is stronger than this, the developer is excessively adsorbed, which becomes a resistance to the rotation of the screw transport body 19, and the rotational load increases.

As another form of the seal member, instead of using the magnet 33, a soft material such as felt or a low friction material such as Teflon sheet can be used, as shown in FIG. 5 (a). A sealing member 34 is provided in the radial direction, and the tip of the sealing member 34 is brought into contact with the inner surface of the cylinder 13.
Alternatively, as shown in FIG. 3B, the sealing member 34 is provided at the tip of the rib 31 and is brought into contact with the inner surface of the cylinder 13.
The seal member 34 is adhered to the rib 31 or directly attached to the transport shaft 17. Such a seal member 34
Thus, the gap L between the rib 31 and the cylinder 13 can be closed, and the toner can be prevented from entering. Moreover, since the seal member 34 is easily deformed or has a low friction coefficient, it does not become a resistance when the screw transport body 19 rotates, and thus does not increase the rotational load.

In the toner replenishing device 10 having the above structure,
At the time of shipment, as shown in FIG. 3, if the screw conveying body 19 is positioned in advance so that the shield part 30 covers the toner supply port 14, the toner supply port 14 is cut off from the inside of the toner hopper 12. Therefore, even if vibration or shock is applied, the toner cannot reach the toner supply port 14, and the toner can be prevented from leaking. Then, the toner replenishing device 10 is attached to the developing device 11, and the developing device 11
When toner shortage occurs, the toner is replenished, but when the motor is driven to rotate the screw transport body 19, the shield portion 30 also rotates and the toner supply port 14 is in communication with the inside of the toner hopper 12, and the spiral The toner conveyed in the axial direction by the blades 18 is discharged from the toner supply port 14 and supplied to the developing tank 15. At this time, since the toner is pushed away in the circumferential direction by the ribs 31 protruding in the radial direction, the toner can be smoothly discharged from the toner supply port 14.

When the toner supply is completed, the shield portion 30
The screw carrier 19 at a position where the toner carrier port 14 is covered.
To stop the rotation of. For this, for example, the rotational position of the transport shaft 17 or the gear may be detected, and the rotation control of the screw transport body 19 may be performed based on the position information. In this way, the toner supply port 14 is shielded except when toner is being replenished, and unnecessary toner outflow can be prevented even if vibration or the like is applied. Also, the toner hopper 12
Since the shield portion 30 covers the toner supply port 14 even when toner is replenished to the developing device 11, the toner flows out from the toner supply port 14 as it is and flows into the developing device 11 even if the toner having good fluidity is used. There is nothing to do.

The present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made to the above embodiment within the scope of the present invention. For example, in the above-described embodiment, the toner supply port 14 is located at the end of the toner hopper 12, but as shown in FIG. 6, the toner supply port 14 is located at the center of the bottom of the toner hopper 12 so that the toner is conveyed from both sides. When the spiral blade 18 is formed, two ribs 31 are formed so as to connect the spiral blades 18 on both sides.
Should be formed.

Further, instead of connecting the two ribs 31 to the spiral blade 18, as shown in FIG. 7, a rib 35 or a disc connecting the ends of the two ribs 31 is formed in the circumferential direction, The shield portion 30 may be configured by the four ribs 31 and 35, or the shield portion 30 may be formed by forming an annular rib. As a result, it is possible to easily deal with the toner supply port 14 at any position, and it is also possible to easily deal with the shape of the toner supply port 14.

Further, instead of the shield portion 30 surrounding the toner supply port 14, as shown in FIG. 8, the curved piece 3 is provided at the tip of the rib 31 so as to directly block the toner supply port 14.
6 may be integrally formed to form the shield part 30. Alternatively, the toner supply port 14 may be directly closed by integrally forming a curved piece that connects a part of the tips of the adjacent spiral blades 18. It is more effective to provide a seal member on the surface of each of the curved pieces 36.

As shown in FIG. 9, the rib 31 may be used as it is as a seal member, and a notch 37 or a thin portion may be formed on the tip side of the side surface opposite to the rotating direction of the rib 31. Thus, the tip of the rib 31 is made bendable and brought into contact with the inner surface of the cylinder 13. Since the tips of the ribs 31 rotate while coming into contact with the cylinder 13 while bending, they do not hinder the rotation of the screw transport body 19 and block the gap L between the rib 31 and the cylinder 13. Can be prevented and the toner will not flow out.
This eliminates the need for the sealing member as a separate member, thus eliminating the need for mounting work and allowing resin molding to form them all at once, facilitating the manufacture of the screw carrier 19.

[0033]

As is apparent from the above description, according to the present invention, the toner supply port is closed with a simple structure without using a complicated mechanism by providing a shield part on a part of the screw carrier. Therefore, the toner does not enter the toner supply port, and it is possible to reliably prevent the toner from flowing out from the toner supply port. Since the screw conveyor is positioned so that the shield part always closes the toner supply port except when the toner is supplied to the developing device, the toner supply port is opened to supply the toner to the developing device. Can be supplied, and at other times, the toner can be prevented from leaking from the toner hopper even if the toner is replenished in the toner hopper or vibration is applied. Therefore, since the excess toner does not flow into the developing device, the image quality is not deteriorated and the inside of the machine is not contaminated.
Toner can be replenished.

Further, by providing the seal member for the rib, it is possible to prevent the toner leaking from the gap between the screw carrier and the toner hopper, and to further enhance the shielding effect. Here, if a seal member that magnetically adsorbs the developer to form a shield, or a seal member made of a flexible material or a low friction material is used, it has a shield effect and a rotation resistance of the screw carrier. I won't.

By using such a toner replenishing device, it is possible to prevent the toner from excessively flowing into the developing device, and this toner replenishing device is suitable for a small developing device that uses toner having good fluidity. There is.

[Brief description of drawings]

FIG. 1 is a sectional view of a toner supply device according to an embodiment of the present invention.

FIG. 2 is a view of the toner replenishing device as seen from the toner supply port side.

FIG. 3 is a sectional view of the shield part.

FIG. 4A is a diagram showing ribs connected to a spiral wing;
(B) is a diagram showing ribs not connected to the spiral blade

FIG. 5 is a diagram showing a seal member.

FIG. 6 is a diagram showing shield parts provided at different positions of the screw carrier.

7A and 7B show modified examples of ribs, FIG. 7A is a plan view, and FIG.
Cross section

FIG. 8 is a sectional view showing a modified example of the rib.

FIG. 9 is a view showing a modified example of the seal member.

FIG. 10 is a sectional view of a conventional developing cartridge.

FIG. 11 is a sectional view of a conventional developing cartridge.

FIG. 12 is a perspective view of a toner replenishing device and a developing device.

FIG. 13 is a sectional view of the toner replenishing device.

FIG. 14 is a cross-sectional view of a toner replenishing device including a shutter mechanism in a closed state.

FIG. 15 is a cross-sectional view of a toner replenishing device including a shutter mechanism in an open state.

[Explanation of symbols]

10 Toner supply device 11 Developing device 12 toner hopper 13 cylinder 14 Toner supply port 17 Transport axis 18 spiral wings 19 screw carrier 30 Shield 31 ribs 33 magnets 34 Seal member L void

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-51868 (JP, A) JP-A-9-325589 (JP, A) JP-A-8-334977 (JP, A) JP-A-3- 64782 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/08 112 G03G 15/08 505 G03G 15/08 507

Claims (9)

(57) [Claims] 1. An opening communicating with a developing device is formed at the bottom of a toner hopper, and a spiral blade for conveying toner toward the opening when toner is replenished is formed in the toner hopper.
Screw conveying member is rotatably provided with the subscription
A pair of ribs project from the transport axis of the carrier in the radial direction.
And the circle formed on the rib and the spiral blade or the transport shaft.
A space surrounded by a plate is formed, and the space is
It is larger than the size of the opening so as to completely cover the opening,
A toner replenishing device characterized in that the inside of the toner hopper and the opening are shut off from each other . 2. The rib is formed parallel to the axial direction,
The ends of the ribs are closed to prevent the axial flow of toner.
The toner replenishing device of claim 1, wherein the Flip was. 3. The developing device is connected to the bottom of the toner hopper.
An opening is formed in the toner hopper when replenishing toner.
A spiral wing that conveys toner toward the opening is formed in
The screw conveyor is rotatably installed,
A pair of ribs project from the transport axis of the carrier in the radial direction.
And the rib is a circle formed on the spiral blade or the transport shaft.
Connected to the plate by the rib and spiral wing or disc
The inside of the toner hopper is blocked from the opening, and
The space surrounded by the bu and the spiral wing or disc is
It is larger than the size of the opening and completely covers the opening.
A toner replenishing device characterized by the above. 4. The rib faces the opening of the screw carrier.
It is characterized in that it is provided in the part without spiral wings in the area
The toner replenishing device according to claim 1, 2, or 3. From the gap between the wherein the bottom of the ribs and the toner hopper to the toner is prevented from flowing out, claims 1-4 Neu, characterized in that the sealing member is provided on the rib
The toner replenishing device according to any one of the above. 6. The toner replenishing device according to claim 5, wherein the seal member is formed of a material that magnetically adsorbs the developer and is arranged near the tip of the rib. 7. The toner replenishing device according to claim 5, wherein the sealing member is arranged so as to project from the tip of the rib so as to come into contact with the bottom of the toner hopper. 8. An image forming apparatus, wherein the developing device is detachably provided with the toner replenishing device according to any one of claims 1 to 7. 9. A control device is provided which rotates the screw carrier when replenishing the toner to the developing device and positions the ribs of the screw carrier so as to shield the opening of the toner hopper except when replenishing the toner. The image forming apparatus according to claim 8.