JP3579601B2 - Image forming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus including an agent transfer device that transfers a powder toner or a developer including a toner and a carrier.
[0002]
[Prior art]
In a conventional image forming apparatus, a toner container such as a toner bottle or a cartridge is disposed in or near a unit having a developing device, and the toner is supplied from the toner container directly into the developing device via a toner hopper. Make up. In this case, the transfer of the toner from the toner storage unit to the developing device is performed by a mechanical auger such as a screw or a paddle.
[0003]
However, when the toner is transferred by the mechanical auger means, the toner storage unit and the toner replenishing device must be installed integrally with the developing device or at a position very close to the developing device because the screw can be arranged only in a substantially straight line. Did not get. This complicates the configuration of the toner replenishing device, hinders high cost, low productivity and mechanical maintenance, makes it difficult to secure and maintain the toner quality characteristics, and also enables the user to easily replace the toner container. Had difficulties.
[0004]
Further, a screw pump having a rotor that moves the toner of the developer in the axial direction by rotating, and a fixed stator that has a passage that encloses the rotor inside and that is in contact with and engaged with the rotor inside the passage, It is known that an air supply means for supplying air for fluidizing the developer moved by the screw pump is used to transfer a mixture of toner and air through a flexible pipe ( JP-A-7-219329).
[0005]
In this transfer method using a screw pump, the stored toner can be transferred via a flexible pipe or the like, so that the installation position of the toner storage unit and the toner collection unit is not restricted at all, and the transfer of the toner is simple. Can be performed reliably. Further, in this toner transfer method, stable transfer of the toner can be obtained by fluidizing the mixture with air by the air supply means and transferring the toner in a state, and unnecessary stress is not applied to the transferred toner more. In addition, the transfer toner is less likely to cause agglomeration and thermal fusion.
[0006]
[Problems to be solved by the invention]
However, a screw pump is necessary even in a transfer method using a screw pump that is optimal for transferring the toner, and it is inevitable that the cost increases accordingly.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide an image forming apparatus capable of transferring an agent without applying unnecessary stress without using a screw pump.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention relates to an image forming apparatus including an agent transfer device that transfers a toner contained in an agent container or an agent obtained by mixing a toner and a carrier to a developing device. The container is a container having a closed structure, and the agent container has an air inlet portion connected to an air inlet means at a lower portion in the direction of gravity and an agent outlet portion connected to the developing device, and Accordingly, the agent is discharged from the agent discharge portion and transferred to the developing device by the pressure of the air flowing into the agent storage container from the air inflow portion and the gravity of the agent itself.
[0009]
The present invention is effective when the air inflow means is an air pump and the amount of the agent transferred to the developing device is controlled by controlling the operation of the air pump .
[0010]
Further, the present invention is effective when the agent storage container is made of a bag-shaped and flexible material.
[0015]
Furthermore, the present invention is effective when the connecting member in which the air inflow portion and the agent discharge portion are formed is provided in the agent container.
[0016]
Furthermore, the present invention is effective when the agent discharge section is connected to the developing device via a transfer member.
Furthermore, the present invention is effective when the transfer member is a flexible tube .
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a configuration diagram showing a toner replenishing mechanism of the image forming apparatus according to the present invention, and FIG. 2 is a cross-sectional view showing a part of a developing device on which the toner is replenished.
[0018]
In FIG. 1, the toner replenishing mechanism of the present embodiment replenishes toner to a developing device 10 which is a predetermined portion. The toner replenishing mechanism is a toner storage container 20 serving as an agent storage container for storing toner. Air inflow means 30 for applying a toner transfer force for transferring the toner to the developing device 10.
[0019]
As shown in FIGS. 1 and 2, the developing device 10 includes a developing sleeve 11 arranged opposite to the photoreceptor 1 as an image carrier, a first stirring screw 12, and a second stirring screw 13. I have. The developer in the developing device 10 is circulated by the first stirring screw 12 from left to right in FIG. 2 and by the second stirring screw 13 from right to left. During this circulation, the electrostatic latent image formed on the photoreceptor 1 is developed by the developer transferred to the developing sleeve 11 in the middle of the transport path.
[0020]
As shown in FIG. 2, the developing device 10 is provided with a toner receiving port 14 at a position corresponding to the first stirring screw 12 at the front end of the apparatus, and a connecting member 15 is provided in the toner receiving port 14. A tube 16 as a transfer member is detachably connected to the connection member 15. An air filter 17 is provided on a part of the connection member 15 to evacuate only the air in the mixture of the toner and the air flow from the developing device, thereby preventing toner from escaping from the connecting member 15 and the developing device 10 during toner supply. It is preventing. The toner replenishment position is not limited to one end of the developing device 10 and is arbitrary and is not particularly limited. Further, the developing device 10 is not limited to the illustrated example, but may be of various types requiring toner supply.
[0021]
The toner storage container 20 is configured as a unit separate from the developing device 10, and is disposed at an appropriate position in the image forming apparatus main body so as to maintain a predetermined posture. The space between the toner container 20 and the developing device 10 is connected via the tube 16. As the tube 16, it is very effective to use a flexible tube having a diameter of, for example, 4 to 10 mm and made of a rubber material (eg, polyurethane, nitrile, EPDM, silicon, etc.) having excellent toner resistance. The flexible tube can be piped in any direction of up, down, left and right.
[0022]
FIG. 3 is a partial cross-sectional view showing a toner container as the agent container.
3, the toner container 20 is formed in a bag shape, and a connection member 21 is provided at one end thereof. A toner discharge pipe 22 as a toner discharge portion is inserted into a hole formed in the connection member 21. ing. In this case, the hole of the connection member 21 is formed to have a larger diameter than the outer diameter of the toner discharge tube 22, and a gap is provided between the connection member 21 and the toner discharge tube 22. This gap is an air gap 31 as an air inflow section, and an air pump as air inflow means 30 ( not shown) is connected. The bag-shaped toner storage container 20 is made of a resin such as polyethylene or nylon, and is made of a flexible sheet having a thickness of about 80 to 120 μm in a single-layer or multi-layer configuration. The periphery is welded to form a closed structure. Further, it is effective to deal with static electricity by subjecting the surface of the sheet constituting the toner storage container 20 to aluminum vapor deposition. Furthermore, the connecting member 21 can also be made of resin such as polyethylene or nylon, and if it is set to the same material as the bag portion, it is convenient for recycling.
[0023]
When set in the image forming apparatus, the toner storage container 20 is supported so as to be in the state shown in FIG. Therefore, the toner stored in the toner storage container 20 accumulates on the lower side due to gravity, so that the lower portion of the toner storage container 20 is a toner storage portion. The toner discharge pipe 22 is provided below the toner container 20 and communicates with the toner reservoir. That is, the toner discharge pipe 22 communicates with the toner reservoir without passing through the air layer in the toner container. The air from the air pump flows from the air gap 31 into the toner reservoir of the ner storage container 20. The air pump and the air gap 31 constitute the air flowing means of the present embodiment. Note that an air supply pipe may be provided in place of the air gap 31 so as to be a double pipe with the toner discharge pipe 22, or the air supply pipe may be arranged on the connection member 21 side by side with the toner discharge pipe 22. good.
[0024]
In the toner replenishing device configured as described above, when a toner replenishment signal is issued, the air pump is operated, and air is ejected from the air gap 31 into the container. At this time, since air is blown out from the bottom of the toner storage container 20, the air flows upward while diffusing and fluidizing the stored toner layer. Then, as the air supply is continued, the air pressure in the container increases, and the toner is discharged out of the container by the air pressure and its own gravity. Thereafter, the discharged toner is transferred to the developing device 10 together with the air.
[0025]
The toner stored in the toner storage container 20 in this manner can be transferred to the developing device 10 by air pressure. At this time, the air jetted into the container can smoothly and reliably transfer the toner by air pressure by fluidizing the toner. Further, since the toner container 20 has a funnel shape toward the toner discharge pipe 22, almost all of the toner in the container is discharged without remaining.
[0026]
The inside of the toner storage container 20 is always filled with air, and since the toner storage container 20 is not broken or wrinkled, the frictional resistance of the inner wall surface of the container is reduced. Further, the transfer of the toner by air pressure does not apply mechanical stress to the toner and is fluidized by air, so that the occurrence of toner aggregation, cross-linking phenomenon and the like can be prevented. Further, the transfer of the toner by air pressure is such that the toner properties are always stable regardless of the amount of toner stored in the container, and the stored toner is discharged without remaining in the bag.
[0027]
FIG. 4 is a graph showing the results of an experiment performed using the apparatus of FIG. 3, in which the vertical axis represents the cumulative amount of toner discharged from the toner container, and the horizontal axis represents the cumulative amount of air supplied to the toner container. Supply time.
[0028]
The air pump used in this experiment has a single performance of a maximum static pressure of 18 Kpa and a maximum flow rate of 1.9 L / Min. As the toner container 20, a sheet made of polyethylene and having a thickness of 100 μm was manufactured in a bag shape. The diameter of the toner discharge pipe 22 was 6 mm, and the test was performed in an environment of 25 ° C. and 60% humidity. The toner used was Ricoh color toner type F for (A) and Ricoh PPC toner type 8200 for (B).
[0029]
As a result, as is clear from the graph of FIG. 4, it was confirmed that both of the toners (A) and (B) obtained a toner discharge amount proportional to the air supply time, and that stable toner discharge was possible. Further, in this experiment, it was confirmed that the amount of discharged toner can be controlled by controlling the operation time of the air pump.
[0030]
From the experimental results, the toner replenishing device according to the present invention can perform toner replenishment only by turning on and off the air pump, so that the configuration of the device can be greatly simplified, and a compact and low-cost toner replenishing device can be provided. Can be provided. Further, since no on-off valve or the like is required in the toner transfer path, stable toner transfer performance can be ensured and high durability can be obtained.
[0031]
The drive and control of the toner replenishing apparatus are performed by driving and controlling a drive motor and an air pump by a power outlet (not shown), a power supply, a switch (not shown), and a control circuit. These may use a conventionally well-known technique.
[0032]
In addition, in order to ensure the reliability of toner transfer during toner replenishment, it is important to drive the pump and supply air with the pump at the same time. The supply of air is performed before the pump is driven (air supply after the drive is stopped). It is essential that the process be performed in a better manner. This prevents the toner from remaining in the transfer member (such as a tube), thereby stably supplying the toner.
[0033]
The supply of air into the toner storage container may be the same as the supply timing to the pump, but may be synchronized with the toner supply signal or may be an intermittent supply.
By the way, it is known that the toner used in an electrophotographic image forming apparatus has a very low fluidity and is difficult to transfer.
[0034]
Originally, when transferring the toner, it is not desirable to apply a large mechanical stress to the toner. When an abnormal stress is applied to the toner, blocking (aggregation due to thermal fusion), crushing, etc. of the toner may occur, causing not only deterioration of the toner characteristics and inability to transfer, but also transfer members (coils, screws, pipes, etc.), driving This causes damage to the members. Therefore, when transferring the toner, it is important to devise as little abnormal mechanical stress as possible to the toner.
In the conventional toner replenishing device, since the transfer is performed by the auger and the pipe as described above, the mechanical stress due to the auger and the mechanical stress due to the friction generated between the auger and the pipe must be very large. Did not. In this case, the longer the transfer distance is, the worse the displacement is in the transfer direction. In addition, the torque required to drive the auger becomes very large, and the cost of the driving member and the increase in power consumption cannot be ignored.
[0035]
For these reasons, when it is desired to increase the transfer distance or to change the transfer direction, a multistage transfer in which a plurality of augers and pipes are connected must be performed. This has resulted in further deterioration of toner characteristics, an increase in the number of parts, an increase in cost, a decrease in reliability, a reduction in maintenance and productivity of the apparatus, an increase in the installation volume of the toner supply apparatus, and a decrease in operability. .
[0036]
This toner replenishing device only needs to connect a flexible toner transfer pipe to the developing device 10 of the image forming apparatus, and there is no scattering of toner. In addition, since there is no restriction on the installation position and location of the toner replenishing device with respect to the developing device, it is possible to provide the toner replenishing device in a place where the user can easily perform operability when replacing the toner storage (supply) container.
[0037]
Since the toner storage container 20 is flexible, the container is not bulky , has good handleability during transportation and storage, and does not take up a storage space as compared with a conventional hard bottle such as a cartridge or a bottle. In addition, the used toner storage means is taken from the user to the manufacturer and recycled / reused or incinerated.However, since the toner storage container is a flexible bag, it can be folded, The advantage of good handling at the time of storage and no space required at the time of transportation and storage is further enhanced, and the cost of collection and distribution from the user to the manufacturer can be significantly reduced.
[0038]
As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments, and can be variously modified.
For example, the developer storage container is not limited to toner, and may store developer, and the developer may be supplied to the developing device. Further, the configuration of the developing device to which the toner is supplied may be arbitrary, and the present invention can be applied to an apparatus using a one-component developer instead of a two-component developer as in the above-described embodiment.
[0039]
【The invention's effect】
According to the configuration of the first aspect, the agent stored in the agent container is fluidized, so that the agent is easily transferred to the developing device, and the amount of the agent stored in the agent container remaining after transfer is extremely small. Can be.
[0040]
According to the configuration of the second aspect, the transfer amount of the agent can be easily controlled.
According to the configuration of the third aspect, the volume of the storage container can be easily reduced, and the cost of recycling and the like can be reduced.
[0041]
With the fourth feature, one connector at the container air inlet and and the agent may perform discharge monitor, the connecting member is recycled if easily because the minimum number.
According to the configuration of claims 5 and 6, the agent storage container can be arranged at an arbitrary position.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining a configuration of the present invention.
FIG. 2 is a cross-sectional view illustrating a toner receiving unit of the developing device.
FIG. 3 is a cross-sectional view illustrating an example of the toner container of the present invention.
4 is a graph showing an experimental result using the toner container of FIG. 3;
[Explanation of symbols]
10 Developing device
16 Tube 20 Toner Storage Container 22 Toner Discharge Tube 31 Air Gap

Claims (6)

An image forming apparatus including an agent transfer device that transfers a toner or a mixture of a toner and a carrier stored in an agent storage container to a developing device;
The agent storage container is a container having a closed structure, and the agent storage container is provided with an air inflow portion connected to an air inflow means at a lower portion in the direction of gravity and an agent discharge portion communicating with the developing device, An image forming method, wherein an agent is discharged from the agent discharge portion and transferred to the developing device by the pressure of the air introduced into the agent storage container from the air inflow portion by the air inflow portion and the gravity of the agent itself. apparatus. 2. The image forming apparatus according to claim 1, wherein the air inflow means is an air pump, and an amount of the agent transferred to the developing device is controlled by controlling an operation of the air pump. Forming equipment. 2. The image forming apparatus according to claim 1 , wherein the agent storage container is made of a bag-shaped flexible material. 2. The image forming apparatus according to claim 1 , wherein a connection member having the air inflow portion and the agent discharge portion is provided in the agent storage container. 3. 2. The image forming apparatus according to claim 1 , wherein the agent discharge unit is connected to the developing device via a transfer member. The image forming apparatus according to claim 5, wherein the transfer member is a flexible tube.

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