JP3499697B2 - Toner transfer pump - 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 transfer pump used in an image forming apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, a facsimile or a compound machine thereof, which visualizes an electrostatic latent image formed on a latent image carrier, the latent image carrier can be used. A powdery toner is often used for visualizing, and it is widely used to visualize an electrostatic latent image as a toner image by the toner.

Such toner is transported from one place to another for various purposes. For example, the toner stored in the toner container of the toner supply device may be transferred to the developing device, or the transfer residual toner recovered from the latent image carrier in the cleaning device may be transferred from the cleaning device to the toner recovery container or the developing device. , Is a typical example.

It is already known to use a toner transfer pump for transferring such toner (Japanese Patent Laid-Open No. 7-2).
19329 gazette). The toner transfer pump has a rotor that is driven to rotate and a fixed stator that is arranged so as to enclose the rotor and that is in contact with and engaged with the rotor. It is transferred by the rotation of the rotor. When such a toner transfer pump is used, powdery toner can be transported with high quantification and the flow rate of the toner can be easily controlled.

However, when the pump is used for transferring the toner as described above, the toner enters the contact interface between the stator and the rotor, and at this time, a large pressure is applied to the toner particle, so that the toner particle is deformed. It may be destroyed. Further, the frictional heat generated at the contact interface between the stator and the rotor may soften the resin forming each toner particle, and the toner particles may be fused and aggregated. When such shape deformation or destruction of toner particles occurs, or toner agglomeration occurs, the charging characteristics of the toner change, and when a toner image is formed by such toner, the image quality thereof deteriorates.

Further, due to the above-mentioned frictional heat, the resin constituting the toner particles is further softened, and when the resin is melted, the molten toner may be solidified. This phenomenon is generally called toner blocking. Further, there may be a sticking phenomenon in which toner softened by frictional heat sticks to the surface of the rotor or the stator. When such toner blocking or toner sticking phenomenon occurs and becomes serious, the rotor and the stator are locked, the rotor cannot rotate, and the toner cannot be transferred. In particular, in recent years, there has been a tendency to use a toner having a low melting point in order to reduce the energy required for fixing a toner image. When such a toner is used, it is particularly difficult to fix the toner on the surface of the rotor or the stator. It tends to occur.

As described above, when the toner transfer pump is used to convey the toner, an excellent advantage can be obtained, but on the other hand, a problem peculiar to the toner transfer pump occurs.

[0008]

SUMMARY OF THE INVENTION The present invention has been made based on the above-mentioned novel recognition, and its purpose is to prevent toner particle deformation, destruction, toner aggregation and toner blocking. It is an object of the present invention to provide a toner transfer pump which can suppress the toner adhesion to the surface of the rotor or the stator effectively.

[0009]

[0010]

[0011]

In order to achieve the above-mentioned object, the present invention comprises a rotor which is rotationally driven and a fixed stator which is arranged so as to enclose the rotor and which is in contact with and engaged with the rotor. In the toner transfer pump that transfers the powdery toner sent into the stator by the rotation of the rotor, the stator has JIS A hardness 6
In addition to comprising an elastic body of 0 or less, the main material of the stator is a non-polar rubber, and the absolute value of the difference between the SP value of the non-polar rubber and the SP value of the main material of the toner is 1 or more. A toner transfer pump is proposed (claim 1).

In this case, in the toner transfer pump according to the above claims, the stator is made of an elastic material containing a softening agent, and | SP value of main stator material-SP value of softening agent material | <| It is advantageous that the SP value of the material−the SP value of the softening material | is satisfied (claim 2).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic sectional view showing a main part of an image forming apparatus having a toner transfer pump. The image forming apparatus shown here is a drum-shaped photoconductor 1 which is an example of a latent image carrier, a developing device 2 placed opposite thereto, and a toner supply for supplying powdery toner to the developing device 2. It has a device 3. In this example, the photoconductor 1 and the developing device 2 are arranged inside the main body of the image forming apparatus (not shown), whereas the toner supply device 3 is arranged outside the main body of the image forming apparatus, The device 3 may be arranged in the main body of the image forming apparatus.

The photoconductor 1 is rotatably supported by the frame of the main body of the image forming apparatus, and is rotationally driven clockwise in FIG. At this time, the surface of the photoconductor is uniformly charged to a predetermined polarity by a charging device (not shown), and then the charged surface is imagewise exposed to form a predetermined electrostatic latent image on the surface of the photoconductor. . When the electrostatic latent image passes through the developing device 2, it is visualized by powdery toner.

The developer container 12 of the developing device 2 contains a powdery two-component developer D having a toner and a carrier. As the developer, a one-component developer containing no carrier is used. May be used. The developer D is agitated by the agitating members 8 and 9 which are rotationally driven, and at this time, the toner and the carrier are frictionally charged with opposite polarities. The thus charged developer D is carried and carried on the peripheral surface of the developing sleeve 6 which is rotationally driven in the counterclockwise direction in FIG. 6 is conveyed to the developing area between the photosensitive member 1 and the photosensitive member 1. A magnet (not shown) is internally provided in the developing sleeve 6, and the magnetic force of the magnet causes the developer D to develop.
It is carried on the peripheral surface of.

Toner of the developer conveyed to the developing area is electrostatically transferred to the electrostatic latent image formed on the photoconductor 1 as described above, and the latent image is visualized as a toner image. Be converted. The toner image is transferred to a transfer material (not shown) fed to the photoconductor 1 by the transfer device configured as the transfer charger 13. The transfer material is then conveyed to a fixing device (not shown), where the toner image on the transfer material is fixed. On the other hand, after the transfer of the toner image, the toner remaining on the photoreceptor 1 is collected and removed from the surface of the photoreceptor by a cleaning device (not shown).

The developer scraped off the developing sleeve 6 by the developer regulating blade 10 is guided by the separator 11 and falls to the lower portion of the developer container 12.

While the above-described developing operation is being performed, the toner concentration of the developer D is lowered, and when this is detected by a toner concentration sensor (not shown), a toner replenishing case formed integrally with the developer container 12 is formed. 7 to developer container 1
Toner is replenished to 2. The toner supply case 7 is provided with a toner supply port 14 as shown in FIG. 2, and toner is supplied to the toner supply case 7 through the toner supply port 14 as described later. The supplied toner is conveyed by the toner conveying screw 7a shown in FIG. 1 and is replenished into the developer container 12 by the rotation of the toner replenishing roller 7b provided between the toner replenishing case 7 and the developer container 12. .

An air vent hole 7d is formed in the upper plate 7c of the toner supply case 7, and an air filter 15 is placed therein.

On the other hand, as shown in detail in FIG. 3, the toner supply device 3 has a toner container 16 containing a powdery toner T, and the toner is appropriately introduced into the toner container 16 from the upper opening 3a. Supplied. At the time of supply, the lid 17 is opened.

The upper opening of the toner guide duct 4 is connected to the lower opening 3b of the toner container 16, and the toner container 16
The toner T inside is supplied to the toner guide duct 4.
The motor mounting member 22 fixed to the toner container 16 includes:
The motor 20 is supported, and the output shaft of the motor 20 is connected to a screw shaft 21 having screw blades via a sleeve 23. The screw shaft 21 penetrates the toner guide duct 4 from the upper part to the lower part, and the toner supplied to the duct 4 is conveyed downward by the rotation of the screw shaft 21.

A toner transfer pump 5 is connected to the lower end of the toner guide duct 4. The toner transfer pump 5 shown here has a rotor 24 whose outer peripheral surface is formed in a spiral shape.
And a stator 25 arranged so as to enclose the rotor 24 and fixed, the rotor 24 is connected to the motor 20 via the screw shaft 21, and is rotationally driven by the operation of the motor 20. The rotor 24 is made of a rigid body such as metal or resin. The stator 25 is formed in a tubular shape having a space for accommodating the rotor 24 therein, the inner peripheral surface thereof is formed in a double spiral shape, and the inner peripheral surface thereof is brought into contact engagement with the outer peripheral surface of the rotor 24. . Rotor 24
When is rotated, the powdery toner enters the space S formed between the inner peripheral surface of the stator 25 and the outer peripheral surface of the rotor 24, and the toner is transferred.

The stator 25 is held by an upper holder 26 and a lower holder 27, and the cylindrical upper holder 26 is fixed to the lower portion of the toner guide duct 4.
The stator 25 is fitted and fixed in a lower holder 27 formed in a tubular shape, and the upper portion of the lower holder 27 is detachably connected to the upper holder 26 to be integrated. A toner passage 30 is formed in a lower portion of the lower holder 27, and the toner passage 30 is provided with a toner transfer pipe 32.
It is connected to the toner supply port 14 of the toner supply case 7 shown in FIG. In FIG. 1, the toner transfer pipe 32 is shown in a simplified manner by the alternate long and short dash line.

As described above, the toner transfer pump 5 shown as an example in the drawing is constituted as a screw pump known as a mono pump, and is of a rotary displacement type and a pressure transfer type.

When a toner remaining amount sensor (not shown) detects that the amount of toner in the toner replenishing case 7 is below a certain amount, the motor 20 starts to rotate by a command based on this, and the screw Shaft 21 and rotor 2
4 are rotationally driven together. In this way, the toner that has flowed down from the toner storage portion formed of the toner container 16 to the toner guide duct 4 is conveyed downward by the rotation of the screw shaft 21 and further downward by the rotation of the rotor 24. In this way, the toner transfer pump 5 transfers the powdery toner sent into the stator 25 by the rotation of the rotor 24.

The toner discharged from the toner transfer pump 5 passes through the toner passage 30 of the lower holder 27 and the toner transfer pipe 32, and the toner supply port 1 of the toner supply case 7 shown in FIG.
The toner conveyed to the case 4 and fed into the case 7 is conveyed by the toner conveying screw 7a shown in FIG.

During the above-described toner conveying operation, the fan 28 arranged above the motor 20 shown in FIG. 3 is rotationally driven by the operation of the motor 20. As a result, the outside air is sucked through the air intake port 28a provided in the upper portion of the fan 28, the air is discharged through the air discharge ports 28b and 28c, and then the air supply port is passed through the pipe schematically shown by a chain line in FIG. It is introduced into the upper holder 26 and the lower holder 27 from 29 and 31. The air supply amount at this time is a small amount of, for example, about 0.5 to 2 liters / minute, and the air flow promotes fluidization of the toner, and the toner transfer pump 5 reliably transfers the toner. . This air contributes to the transfer of toner and then
And is discharged to the outside through the air filter 15 shown in FIG.

As described above, the powdery toner is conveyed to the developing device 2 by the toner transfer pump 5. By using the pump 5, it becomes possible to control the flow rate of the conveyed toner with high accuracy and high accuracy.

The above is the configuration and operation common to the toner transfer pump 5 described below, and is a configuration example common to claims 1 and 2.

Here, the rotor 24 constituting the toner transfer pump 5 is made of a rigid body such as metal or resin as described above. On the other hand, conventionally, the stator 25 is also usually made of a rigid body such as metal or ceramics. However, the rotor 24
When both the stator 25 and the stator 25 are made of a rigid body, when the transported toner enters the contact interface between the rotating rotor 24 and the fixed stator 25, a large pressure is applied to the toner particles. Therefore, in the conventional toner transfer pump, the toner particles under pressure may be deformed or destroyed, and the frictional heat generated at the contact interface between the stator and the rotor softens the resin of the toner particles, This may cause aggregation of the toner.

Since such a toner changes in characteristics such as charge amount, when such a toner is used for visualizing the electrostatic latent image formed on the photoconductor 1, the toner image formed by the toner is formed. Image quality deteriorates.

Further, in the conventional toner transfer pump,
The molten toner solidifies and causes toner blocking, or the molten toner adheres to the surface of the stator or rotor,
There is a possibility that the rotor cannot be rotated and toner cannot be transferred.

Further, when both the rotor and the stator of the toner transfer pump are made of a rigid body, the strong frictional contact between them causes the materials constituting them to be slightly scraped off, and these become foreign matters and enter the toner. When such toner is conveyed to a developing device and used for development,
The mixed foreign matter scratches the photoconductor and the agent regulating blade, which also deteriorates the image quality of the toner image.

Further, if the rotor and the stator are made of a rigid body, the frictional force between them becomes large, so that the driving torque for rotationally driving the rotor becomes large, and the motor for driving the rotor must be made large.

As shown in Japanese Patent Laid-Open No. 7-219329, it is known that the stator is made of an elastic material. However, if the stator is simply made of an elastic material, the above-mentioned problems cannot be avoided. Can not.

Therefore, in the toner transfer pump 5 of the present embodiment, the stator 25 is not limited to the elastic body, but is formed of the elastic body having JIS A hardness of 60 or less. The stator 25 is made of a soft elastic material such as rubber.

The reason why the stator 25 is set to JIS A hardness of 60 or less will be clarified later, but when the stator 25 is made of such a soft elastic body, the rotor 24 is made of a rigid body as described above. However, when the toner particle size passes between the rotor 24 and the stator 25, the stator portion pressed by the rotor 24 elastically deforms, so that the external force applied to the toner particle becomes small, and The applied stress can be reduced. Therefore, it is possible to prevent the toner particles from being deformed or destroyed. In addition, since the stator 25 elastically deforms when the rotor 24 rotates, the heat generated by the friction between the two can be suppressed to an extremely low level, which can prevent the toner from aggregating. Since the toner image is formed on the photoconductor 1 by the toner, the image quality can be improved. Also, when the toner collected and removed from the photoconductor by the cleaning device is used again for visualizing the electrostatic latent image, a high quality toner image can be formed by the toner.

Moreover, since it is possible to suppress the generation of frictional heat, the toner is melted and causes blocking as in the conventional case, and the melted toner is fixed to the outer peripheral surface of the rotor 24 and the inner peripheral surface of the stator 25. Can be prevented,
The rotor 24 can always be rotated in a normal state.

Furthermore, when the rotor 24 rotates, the stator 2
Since 5 is elastically deformed, the frictional force acting on the rotor 24 is reduced, and the rotor 24 can be rotated with a small driving torque. Therefore, a small motor 20 can be used. In addition, the rotor 24 and the screw shaft 21
If the main motor of the image forming apparatus and the rotor 24 are drivingly connected and the rotor 24 is rotated by the main motor instead of using a dedicated motor for use in the image forming apparatus, the cost of the image forming apparatus can be reduced. Since the main motor is loaded with a large number of elements, it is necessary to reduce the load of each individual element. When the material of the stator 25 is set as described above, the driving torque of the rotor 24 can be reduced. Therefore, even if the rotor 24 is driven by the main motor, the load on the main motor can be reduced, and this configuration is hindered. Can be adopted without.

Further, since the stator 25 is made of a soft elastic material, the frictional force acting on the stator 25 and the rotor 24 is reduced, so that the constituent material of the rotor 24 is scraped when the rotor 24 rotates. However, it is possible to effectively suppress the problem that the powdery small particles are mixed in the toner, and it is possible to form a high-quality toner image.

Next, in the toner transfer pump 5 of this example, the main material of the stator 25 is made of non-polar rubber,
The absolute value of the solubility index of the nonpolar rubber, that is, the difference between the SP value and the SP value of the main material of the toner is 1 or more. The difference in SP value between the two is 1 or more.
Here, this configuration is referred to as a second configuration, and the stator is JI.
The above-mentioned structure, which is constituted by an elastic body having an SA hardness of 60 or less, will be referred to as a first structure.

The above-mentioned second structure can be adopted separately from the first structure. It is also possible to employ both the first and second configurations, which is particularly advantageous. That is, the stator 25 has JIS A hardness of 60.
In addition to the following elastic body, the main material of the stator 25 is made of non-polar rubber, and the absolute value of the difference between the SP value of the non-polar rubber and the SP value of the main material of the toner is 1 or more. Of. This is the third configuration.

Also in the above-mentioned second structure, the stator 2
Since the main material forming the member 5 is made of rubber, it is possible to eliminate the drawbacks found in the conventional toner transfer pump in which both the stator and the rotor are made of rigid bodies, and the same effects as the first structure can be obtained. It is possible. Moreover,
According to the second configuration, the main material of the stator 25 is generally made of non-polar rubber having excellent releasability, and the S
The absolute value of the difference between the P value and the SP value of the toner main material, which is usually a resin, is 1 or more, and the SP values of the two are greatly separated, so the releasability of the stator 25 from the toner is greatly improved. To be Therefore, even if the toner transfer pump 5 is operated for a long time, it is possible to effectively prevent the toner transferred in the stator 25 from sticking to the inner peripheral surface of the stator 25. As a result, the rotor 24 can be rotated in a stable state, and the reliability of the toner transfer pump can be improved. In addition, this second configuration and the above-mentioned first configuration
According to the third configuration in which the above configurations are combined, it is possible to further improve the image quality of the toner image and the reliability of the toner transfer pump.

The toner is usually composed of a polar resin as a main material, but as a base polymer of the stator 25,
By using a non-polar rubber as described above, the releasability of the toner can be improved.
Examples of such non-polar resins include butadiene rubber (SP value 8.4), ethylene propylene rubber (SP value 8.0), natural rubber (SP value around 8), isoprene rubber (SP value 8.1). , Silicone rubber (SP value 7.3 to 7.6) and the like.
5 can be used as the main material.

However, the silicone rubber is slightly inferior in abrasion resistance to the other rubbers exemplified above, and when the stator 25 is formed by using this as a main material, the stator 25 is constituted by friction with the rotating rotor 24. The main material is slightly scraped off, and this may be mixed into the toner as foreign matter. Therefore, as shown in FIG. 1, in the case of the toner transfer pump 5 that transfers toner used for visualizing an electrostatic latent image, use of silicone rubber as the main material of the stator 25 should be avoided. Is safe.

The toner transfer pump transfers the toner image formed on the photoconductor to a transfer material, removes the toner remaining on the photoconductor by a cleaning device, and collects the removed and collected toner in a toner recovery container. The toner can be used even when it is conveyed, and in the toner transfer pump used for such a purpose, silicone rubber can be used as a main material of the stator without any trouble. Even if some foreign matter is mixed in the transferred toner, the toner is transported to the toner collection container and is not used for visualizing the electrostatic latent image and is discarded. Therefore, it does not cause any problem.

Fluorine rubber (SP value 7.3) is a polar rubber, but since it has excellent releasability, even if this fluorine rubber is used as the main material of the stator 25, the toner adheres to it. Can be prevented. However, fluororubber is extremely expensive, has a difficulty in its workability, and there is no effective means for lowering the hardness. Considering these points, fluororesin alone is used as the main material of the stator. There is no merit to use.

Here, the experimental results concerning the toner releasability of the non-polar rubber and the polar rubber will be introduced. As the base polymer, a stator made of non-polar rubber ethylene propylene rubber and butadiene rubber and a stator made of polar rubber nitrile rubber (SP value 9.5) were prepared. In all cases, pure rubber was compounded with almost only the vulcanizing agent, and the factors of other mixtures were minimized.

The above-mentioned three types of stators were immersed in toner powder, left at 45 ° C. for 3 days, and then taken out.
When the toner was removed by air-blowing on each of the stators, toner adhesion was not observed on the stator made of ethylene propylene rubber or butadiene rubber. On the other hand, the toner was fixed on the entire surface of the stator made of nitrile rubber. From this, it can be understood that by using the non-polar rubber as the main material of the stator, it is possible to prevent the problem that the toner adheres to the non-polar rubber.

In the first to third configurations of the stator 25 described above, in order to make the stator a soft elastic body, the stator is usually made of an elastic material containing a softening agent. A softening agent is used to control the hardness of rubber to a low level, and depending on the type of the softening agent, this may exude to the rubber surface. If the stator 25 is made of an elastic material containing such a softening agent, the softening agent oozes out to the inner peripheral surface of the stator during its use, which causes toner to adhere to the stator, which causes It may interfere with the rotation.

Therefore, in this embodiment, in the toner transfer pump 5 having the above-mentioned first to third structures, the stator 25 is made of an elastic material containing a softening agent, and |
The SP value of the main stator material-the SP value of the softening agent material | <| the SP value of the main toner material-the SP value of the softening agent material | The absolute value of the difference between the SP value of the main material of the stator and the SP value of the softening material is set smaller than the absolute value of the difference between the SP value of the main toner material and the SP value of the softening material. This is the fourth configuration.

If the stator 25 is constructed as described above,
The softening agent is more easily dissolved in the main material of the stator than in the main material of the toner, and the softening agent can be prevented from bleeding toward the toner. Therefore, even when the toner transfer pump is operated for a long time, the softening agent can be prevented from oozing out from the stator 25, the toner can be prevented from sticking to the stator 25, and the rotation of the rotor 24 can be prevented from being hindered. it can. According to the fourth structure, the stator 25 can be softened by the softening agent, and thus the function and effect described above in relation to the first structure can be obtained, and the stator 25 is contained. The softening agent can prevent the toner from sticking to the stator.

Next, the meaning of each numerical value defined as described above will be clarified by introducing a part of many experiments conducted by the present inventor.

First, JIS A hardness is 30, 40, 5
A stator was made of each material showing 0, 60, 70 and 80. As the base polymer, a non-polar rubber butadiene rubber was used, and a softening agent was added to the butadiene rubber to form a soft JIS A hardness 30 stator. Also JIS
For each of the stators having A hardness of 50, 60, 70 and 80, carbon was added to the base polymer and the hardness of each stator was adjusted by the amount thereof. JIS A hardness 4
The No. 0 stator contains neither softener nor carbon. Paraffin-based process oil (P400 manufactured by Fuji Kosan Co., Ltd.) was used as a softening agent.

Each of the stators manufactured as described above is combined with a rotor to form a toner transfer pump, and the rotor is rotationally driven at a rotational torque (250 rpm) of a certain condition.
The powdery toner was transferred by the pump. FIG. 4 shows the drive torque value of the rotor in each toner transfer pump at this time. The vertical axis of this figure shows the drive torque (N · m), and the horizontal axis shows the hardness of each stator. From this figure, it can be understood that the drive torque of the rotor increases as the hardness of the stator increases. The torque value is influenced by the shape of the rotor (cross-sectional area, eccentricity), the shape of the inner surface of the stator, and the combined condition of the rotor and the stator (bite depth).
It is clear that the torque value increases.

Further, each of the toner transfer pumps was continuously operated, and the operating time and the toner temperature at this time were measured. The results are shown in Table 1 below.

[0058]

[Table 1]

In a toner transfer pump having a stator having JIS A hardness of 70 and 80, the toner was blocked near the toner outlet of the pump after continuous operation for about 50 hours, and the rotation of the rotor was stopped. This is because, as can be seen from Table 1, the temperature on the outlet side of the toner transfer pump had risen to 60 ° C. or higher, and it is considered that the frictional force between the rotor and the stator had an effect. No toner blocking was observed in toner transfer pumps with stators of other hardness.

When a large number of similar experiments were repeated, the common result is that if the stator is made of an elastic body having JIS A hardness of 60 or less, toner blocking does not occur even when the toner transfer pump is operated for a long time. Became clear.

Further, even after continuously operating the respective toner transfer pumps having the stators of the respective hardnesses shown in Table 1, the toner did not adhere to the stator. this is,
The toner used is a polystyrene resin base, and the SP value of polystyrene is 9.6, whereas the SP value of the butadiene rubber, which is the main material of the stator, is 8.4, and the two values greatly differ from each other. This is because the butadiene rubber and the polystyrene resin are hard to melt.

When a large number of similar experiments were repeated, the common result was that the main material of the stator consisted of non-polar rubber, the SP value of the non-polar rubber and the SP of the main material of the toner.
It has been found that when the absolute value of the difference between the values is 1 or more, it is possible to effectively prevent the toner from sticking to the stator.

Among the hardnesses shown in Table 1, JIS
A stator having an A hardness of 30 was obtained by adding 12 parts of a softening agent to 100 parts of butadiene rubber, but no bleeding of the softening agent was observed even after a toner transfer pump having such a stator was continuously operated. This is because the SP value of the process oil used as the softening agent is 6.5, and the softening agent is more easily soluble in the butadiene rubber which is the main material of the stator than the polystyrene which is the base resin of the toner. Conceivable.

When a large number of similar experiments were repeated, the common result was that the stator was composed of an elastic material containing a softening agent, and | SP value of main stator material-SP value of softening material | <| It was confirmed that when the SP value of the toner main material-the SP value of the softening agent material is satisfied, there is no bleeding of the softening agent and it is possible to prevent the toner from sticking to the stator. In the above experimental example, the SP value of butadiene rubber, which is the main material of the stator, is 8.4, and the SP value of the softening agent is 6.
5, since the SP value of the toner main material is 9.6, (8.
4-6.5) <(9.6-6.5).

The present invention can be widely applied to a toner transfer pump of an image forming apparatus other than the image forming apparatus of the type shown in FIGS.

[0066]

[0067]

[0068]

According to the toner transfer pump of the first aspect of the present invention, since the stator is made of the elastic body of low hardness,
It is possible to prevent the toner from being deformed, destroyed, and agglomerated due to the contact pressure with the rotor, and to prevent the toner from sticking to the stator and the rotor. Moreover, since the releasability of the stator from the toner can be improved, it is possible to prevent the toner from sticking to the stator even when the pump is operated for a long time. Therefore, it is possible to prevent problems that hinder the rotation of the rotor and improve the reliability of the pump.

According to the toner transfer pump of the second aspect, even when the softening agent is used to reduce the hardness of the stator, it is possible to prevent the toner from sticking to the stator, thereby impairing the rotation of the rotor. Can be prevented and the reliability of the pump can be improved.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an image forming apparatus having a toner transfer pump.

FIG. 2 is an external perspective view of a toner supply case.

FIG. 3 is a vertical cross-sectional view of a toner supply device.

FIG. 4 is a diagram showing an example of the relationship between the hardness of the stator and the drive torque of the rotor.

[Explanation of symbols]

5 Toner transfer pump 24 rotor 25 stator T toner

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-219329 (JP, A) JP-A-8-202130 (JP, A) JP-A-4-70683 (JP, A) JP-A-7- 92794 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/08 112 G03G 15/08 507

Claims (2)

(57) [Claims] 1. A rotary driven rotor, and a fixed stator which is arranged so as to enclose the rotor and is in contact with and engaged with the rotor. In the toner transfer pump that transfers by rotation of the rotor, the stator is made of an elastic body having JIS A hardness of 60 or less, the main material of the stator is made of non-polar rubber, and the SP value of the non-polar rubber and the main material of toner are The toner transfer pump is characterized in that the absolute value of the difference from the SP value is 1. 2. A stator is made of an elastic material containing a softening agent, and | SP value of stator main material-SP value of softening material | <| SP value of toner main material-SP value of softening material | The toner transfer pump according to claim 1, wherein: