JP2009216972A - Single shaft eccentric screw suction pump, powder toner transfer device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stop a pump when torque increases due to the unpredictable shortage of fine particles, thereby preventing damage to the pump and fine particles. <P>SOLUTION: In a single shaft eccentric suction screw pump 60 which has a stator 62 with a female threaded hole and a male threaded rotor 61 inserted into the threaded hole and turned by the drive shaft 64 connected to the drive source, and is used to carry fine particles from the suction hole to the transfer route, a clutch 66 and a torque limiter 68 are provided between the drive shaft 64 and the motor 67. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a suction-type single-shaft eccentric screw pump, a powder toner conveying device, and an image forming apparatus, and in particular, a stator having a female screw-shaped hole, and a stator disposed in the spiral hole and connected to a driving source. A suction-type single-shaft eccentric screw pump that includes a male screw-shaped rotor that is rotationally driven by a drive shaft and that transports powder from a suction port to a transport path, a powder toner transport device including the pump, and the transport device The present invention relates to an image forming apparatus.

  In general, one of the image forming systems is an electrophotographic copying system, and an apparatus using this system includes an image forming apparatus such as a copying machine, a printer, or a facsimile machine.

  In the electrophotographic copying method, an electrostatic latent image is formed on a photoconductor that forms a uniformly charged image carrier by exposure or optical writing, and this electrostatic latent image is mixed with, for example, a magnetic carrier and toner. A copy is obtained by transferring an image that has been subjected to visible image processing using a two-component developer toner or a one-component developer in which both are integrated to a recording paper or the like.

  The developer used for the visible image processing increases in consumption as the visible image processing continues, and the density at the time of supply decreases. Among the above-described developers, in the case of a two-component developer, the amount of toner decreases with time, the toner concentration in the developer decreases, and a desired image density cannot be obtained.

Therefore, in order to suppress a decrease in image density, when the toner density in the developer becomes a predetermined value or less, the toner is replenished to maintain the toner density in the developer in a stable state. . In order to replenish the toner of such an electrophotographic apparatus, a screw pump is used (see Patent Document 1).
Japanese Patent No. 3434085

  By the way, in a suction type single-shaft eccentric screw pump which is a kind of screw pump used for conveying powder such as powder toner, powder interposed between a rotor and a stator inside the screw pump serves as a lubricant. The driving torque is kept almost constant.

  However, if the powder at the transportation source disappears or the conveyance path is clogged, the powder in the pump becomes insufficient, the friction between the rotor and the stator increases, and the driving torque of the pump increases. In addition, there is a problem that the powder is damaged by the frictional heat generated at this time.

  Further, when the powder is toner, since the resistance to heat is low, there is a problem that the toner melts and adheres to the rotor / stator and the pump cannot be driven.

  Therefore, the present invention provides a suction-type single-shaft eccentric screw pump capable of preventing the powder and the pump from being damaged by stopping the driving of the pump when the torque increases due to an unexpected powder shortage. An object is to provide an apparatus and an image forming apparatus.

  The invention of claim 1 includes a stator having a female screw-like hole, and a male screw-like rotor that is rotationally driven by a drive shaft that is disposed in the spiral hole and connected to a drive source, The suction-type single-shaft eccentric screw pump that transports powder to a transport path includes a torque limiter between the drive shaft and the drive source.

  According to a second aspect of the present invention, in the suction type single-shaft eccentric screw pump according to the first aspect, a clutch is provided between the drive shaft and the drive source.

  A third aspect of the present invention is the suction type single-shaft eccentric screw pump according to the first or second aspect, wherein the set torque value of the torque limiter is set to be substantially the same as the initial drive torque value of the pump. And

  According to a fourth aspect of the present invention, in the suction type single-shaft eccentric screw pump according to any one of the first to third aspects, the rotation state of the drive shaft is detected, and a rotation stop signal is generated when the drive shaft stops. It is characterized by comprising stop detecting means for performing.

  According to a fifth aspect of the present invention, in the suction type single-shaft eccentric screw pump according to the fourth aspect, a rotation stop signal corresponding to the operation of the driving source is coefficiented, and the driving control of the driving source is performed based on the coefficient value. It is characterized by comprising drive control means for performing.

  According to a sixth aspect of the present invention, in the suction type single-shaft eccentric screw pump, the control unit does not drive the driving unit according to a coefficient value of the detection signal.

  A seventh aspect of the present invention is a powder toner conveying device comprising the suction type single-shaft eccentric screw pump according to any one of the first to sixth aspects.

  According to an eighth aspect of the present invention, there is provided an image forming apparatus comprising the powder toner conveying device according to the seventh aspect.

  According to the suction type single-shaft eccentric screw pump, the powder toner conveying device, and the image forming apparatus according to the present invention, a torque limiter is provided between the drive shaft that rotates the rotor and the drive source that rotationally drives the drive shaft. As a result, power transmission from the drive source is stopped and the rotor rotation is stopped when the torque of the drive shaft exceeds a predetermined value when powder in the pump is unexpectedly insufficient. In addition, it is possible to prevent the suction type single-shaft eccentric screw pump from being damaged.

  Embodiments as the best mode for carrying out the present invention will be described below with reference to the drawings.

  First, the configuration and operation of the entire image forming apparatus will be described. 1 is an overall configuration diagram illustrating a printer as an image forming apparatus, FIG. 2 is an enlarged view illustrating an image forming unit of the image forming apparatus, and FIG. 3 is a schematic diagram illustrating a toner supply path of the image forming apparatus.

As shown in FIG. 1, the toner container housing 31 above the apparatus main body 100 has four toners corresponding to the respective colors (yellow (Y), magenta (M), cyan (C), and black (K)). The containers 32Y, 32M, 32C, and 32K are detachably (replaceable).
An intermediate transfer unit 15 is disposed below the toner container housing 31. Image forming portions 6Y, 6M, 6C, and 6K corresponding to the respective colors (Y, M, C, and K) are arranged in parallel so as to face the intermediate transfer belt 8 of the intermediate transfer unit 15.

  As shown in FIG. 2, the image forming unit 6Y corresponding to yellow includes a photosensitive drum 1Y, a charging unit 4Y disposed around the photosensitive drum 1Y, a developing device 5Y (developing unit), a cleaning unit 2Y, It is composed of a static eliminator (not shown). Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photosensitive drum 1Y, and a yellow image is formed on the photosensitive drum 1Y.

The other three image forming units 6M, 6C, and 6K have substantially the same configuration as that of the image forming unit 6Y corresponding to yellow except that the color of the toner used is different. A corresponding image is formed. Hereinafter, description of the other three image forming units 6M, 6C, and 6K will be omitted as appropriate, and only the image forming unit 6Y corresponding to yellow will be described.

  The photosensitive drum 1Y is rotationally driven in a clockwise direction in FIG. 2 by a drive motor (not shown). Then, the surface of the photosensitive drum 1Y is uniformly charged at the position of the charging unit 4Y (a charging process). After that, the surface of the photosensitive drum 1Y reaches the irradiation position of the laser beam L emitted from the exposure device 7 (see FIG. 1), and the electrostatic latent image corresponding to yellow by exposure scanning at this position. Is formed (this is an exposure step).

  Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the developing device 5Y, and the electrostatic latent image is developed at this position to form a yellow toner image (developing step). Next, the surface of the photosensitive drum 1Y reaches a position facing the intermediate transfer belt 8 and the first transfer bias roller 9Y, and the toner image on the photosensitive drum 1Y is transferred onto the intermediate transfer belt 8 at this position. (This is a primary transfer step.) At this time, a small amount of untransferred toner remains on the photosensitive drum 1Y.

Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the cleaning unit 2Y, and untransferred toner remaining on the photosensitive drum 1Y is mechanically collected by the cleaning blade 2a at this position (cleaning step). . Finally, the surface of the photosensitive drum 1Y reaches a position facing a neutralization unit (not shown), and the residual potential on the photosensitive drum 1Y is removed at this position.
Thus, a series of image forming processes performed on the photosensitive drum 1Y is completed.

The image forming process described above is performed in the other image forming units 6M, 6C, and 6K in the same manner as the yellow image forming unit 6Y. That is, the laser beam L based on the image information is emitted from the exposure device 7 disposed below the image forming unit onto the photosensitive drums of the image forming units 6M, 6C, and 6K. Specifically, the exposure unit 7 emits laser light L from a light source, and irradiates the photosensitive drum through a plurality of optical elements while scanning the laser light L with a polygon mirror that is rotationally driven.
Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the developing process are transferred onto the intermediate transfer belt 8 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 8.

  Here, as shown in FIG. 1, the intermediate transfer unit 15 includes an intermediate transfer belt 8, four primary transfer bias rollers 9Y, 9M, 9C, and 9K, a secondary transfer backup roller 12, a cleaning backup roller 13, and a tension roller. 14 and the intermediate transfer cleaning unit 10. The intermediate transfer belt 8 is stretched and supported by the three rollers 12 to 14 and is endlessly moved in the direction of the arrow in FIG.

  The four primary transfer bias rollers 9Y, 9M, 9C, and 9K respectively sandwich the intermediate transfer belt 8 with the photosensitive drums 1Y, 1M, 1C, and 1K to form a primary transfer nip. Then, a transfer bias reverse to the polarity of the toner is applied to the primary transfer bias rollers 9Y, 9M, 9C, and 9K.

  The intermediate transfer belt 8 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer bias rollers 9Y, 9M, 9C, and 9K. In this way, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred while being superimposed on the intermediate transfer belt 8.

  Thereafter, the intermediate transfer belt 8 on which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19. At this position, the secondary transfer backup roller 12 sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 to form a secondary transfer nip. The four-color toner images formed on the intermediate transfer belt 8 are transferred onto a transfer material P such as transfer paper conveyed to the position of the secondary transfer nip. At this time, the untransferred toner that has not been transferred to the transfer material P remains on the intermediate transfer belt 8.

  Thereafter, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning unit 10. At this position, the untransferred toner on the intermediate transfer belt 8 is collected. Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

  Here, the transfer material P transported to the position of the secondary transfer nip is transported from a paper feed unit 26 disposed below the apparatus main body 100 via a paper feed roller 27, a registration roller pair 28, and the like. It has been done.

  Specifically, a plurality of transfer materials P such as transfer paper are stored in the paper supply unit 26 in a stacked manner. When the paper feed roller 27 is rotated in the counterclockwise direction in FIG. 1, the uppermost transfer material P is fed between the rollers of the registration roller pair 28.

  The transfer material P conveyed to the registration roller pair 28 is temporarily stopped at the position of the roller nip of the registration roller pair 28 that has stopped rotating. Then, the registration roller pair 28 is rotationally driven in synchronization with the color image on the intermediate transfer belt 8, and the transfer material P is conveyed toward the secondary transfer nip. In this way, a desired color image is transferred onto the transfer material P.

  Thereafter, the transfer material P on which the color image has been transferred at the position of the secondary transfer nip is conveyed to the position of the fixing unit 20. At this position, the color image transferred to the surface is fixed on the transfer material P by heat and pressure generated by the fixing roller and the pressure roller. Then, the transfer material P is discharged out of the apparatus through the rollers of the pair of paper discharge rollers 29. The transferred P discharged from the apparatus by the discharge roller pair 29 is sequentially stacked on the stack unit 30 as an output image. Thus, a series of image forming processes in the image forming apparatus is completed.

  Next, the configuration and operation of the developing device in the image forming unit will be described in more detail. As shown in FIG. 2, the developing device 5Y includes a developing roller 51Y that faces the photosensitive drum 1Y, a doctor blade 52Y that faces the developing roller 51Y, and two transport screws disposed in the developer accommodating portions 53Y and 54Y. 55Y, a density detection sensor 56Y for detecting the toner density in the developer, and the like. The developing roller 51Y includes a magnet fixed inside, a sleeve rotating around the magnet, and the like. In the developer accommodating portions 53Y and 54Y, a two-component developer G composed of a carrier and a toner is accommodated. The developer accommodating portion 54Y communicates with the toner transport pipe 43Y through an opening formed thereabove.

The developing device 5Y configured as described above operates as follows. The sleeve of the developing roller 51Y rotates in the direction of the arrow in FIG. The developer G carried on the developing roller 51Y by the magnetic field formed by the magnet moves on the developing roller 51Y as the sleeve rotates.

  Here, the developer G in the developing device 5Y is adjusted so that the ratio of toner in the developer (toner concentration) is within a predetermined range. Specifically, according to the consumption of toner in the developing device 5Y, the toner stored in the toner container 32Y is supplied into the developer storage portion 54Y via the toner supply device 59 (see FIG. 3). .

  Thereafter, the toner replenished in the developer accommodating portion 54Y is circulated through the two developer accommodating portions 53Y and 54Y while being mixed and stirred together with the developer G by the two conveying screws 55Y (perpendicular to the paper surface in FIG. 2). Direction movement.) The toner in the developer G is attracted to the carrier by frictional charging with the carrier, and is carried on the developing roller 51Y together with the carrier by the magnetic force formed on the developing roller 51Y.

  The developer G carried on the developing roller 51Y is conveyed in the direction of the arrow in FIG. 2 and reaches the position of the doctor blade 52Y. The developer G on the developing roller 51Y is conveyed to a position facing the photosensitive drum 1Y (development region) after the developer amount is made appropriate at this position. The toner is attracted to the latent image formed on the photosensitive drum 1Y by the electric field formed in the development area. Thereafter, the developer G remaining on the developing roller 51Y reaches above the developer containing portion 53Y as the sleeve rotates, and is detached from the developing roller 51Y at this position.

  Next, the toner replenishing device 59 that guides the toner stored in the toner container 32Y to the developing device 5Y will be described in detail with reference to FIG. Note that FIG. 3 illustrates the toner container 32Y, the toner transport pipe 43Y, the screw pump 60, the nozzle 70, the tube 71, and the developing device 5Y in different arrangement directions for easy understanding. Actually, in FIG. 3, the toner container 32 </ b> Y and a part of the toner replenishment path are arranged so that the longitudinal direction is perpendicular to the paper surface (see FIG. 1).

  The toner in each of the toner containers 32Y, 32M, 32C, 32K installed in the toner container housing portion 31 of the apparatus main body 100 is a toner replenishment path provided for each toner color according to the toner consumption in the developing device of each color. After that, each developing device is appropriately replenished. The four toner supply paths have substantially the same structure except that the color of the toner used in the image forming process is different.

  When the toner container 32Y is set in the toner container housing portion 31 of the apparatus main body 100, the nozzle 70 of the toner container housing portion 31 is connected to the held portion 34Y of the toner container 32Y. As the container body 33Y of the toner container 32Y is driven to rotate, the toner stored in the container body 33Y is discharged from the toner discharge port, and the toner discharged from the toner discharge port is transferred into the nozzle 70. .

  On the other hand, the other end of the nozzle 70 is connected to one end of a tube 71 as a transport pipe. The tube 71 is made of a flexible material excellent in toner resistance, and the other end is connected to a screw pump 60 (Mono pump) of the toner replenishing device. The tube 71 as the transport tube is formed so that its inner diameter is 4 to 10 mm. As the material of the tube 71, a rubber material such as polyurethane, nitrile, EPDM, or silicon, or a resin material such as polyethylene or nylon can be used. By using such a flexible tube 71, the degree of freedom in the layout of the toner supply path is increased, and the image forming apparatus is downsized.

  Next, the toner replenishing device will be described. FIG. 4 is a schematic diagram illustrating the configuration of the toner supply device according to the embodiment. The screw pump 60 is configured as a suction type uniaxial eccentric screw pump. That is, the screw pump 60 includes a rotor 61, a stator 62, a universal joint 63, and a drive shaft 64. The rotor 61, the stator 62, the universal joint 63, and the drive shaft 64 are accommodated in the case 65.

  The stator 62 is an internally threaded member made of an elastic material such as rubber, and a double pitch spiral groove is formed in the stator 62. The rotor 61 is a male screw-like member formed by spirally twisting a shaft made of a rigid material such as metal, and is fitted into the stator 62 so as to be freely rotatable. One end of the rotor 61 is rotatably connected to the drive shaft 64 via the universal joint 63.

  In the case 65, a clutch 66 having an input gear 66a is connected to the drive shaft 64, and a drive gear 66b for transmitting a rotational driving force from the motor 67 to the clutch 66 is engaged with the input gear 66a. .

  In this example, the rotational force of the motor 67 is transmitted to the drive gear 66b via the torque limiter 68, and the rotational speed of the motor drive shaft 67a is measured by the rotary encoder encoder 69. In this example, the motor 67 is controlled by the control device 110. Note that the control device 110 is provided in the image forming apparatus, can execute the program by a CPU or the like, and can realize its business by a control unit that controls the image forming apparatus.

  The screw pump 60 configured as described above generates a suction force at the suction port 36 by rotating the rotor 61 in the stator 62 in a predetermined direction by the motor 67 (the air in the tube 71 is sent out to the tube). A negative pressure is generated in 71). As a result, the toner in the toner container 32Y is sucked into the suction port through the tube 71 together with air. The toner sucked up to the suction port is fed into the gap between the stator 62 and the rotor 61, and is sent to the other end side along the rotation of the rotor 61. The delivered toner is discharged from the delivery port of the screw pump 60 and replenished into the developing device 5Y through the toner transport pipe 43Y.

  The toner supply device including the screw pump 60 is basically controlled by a conventionally known developer concentration detection / control system. This control detects a change in the mixing ratio of the toner and the carrier in the developing device based on a magnetic permeability detector (not shown) provided in a part of the developing device. When the toner amount is detected to be small, the screw pump 60 The drive shaft 64 is driven to rotate by a motor 67. When the toner transferred into the developing device by the screw pump 60 exceeds a certain amount, the drive is cut off by the signal of the magnetic permeability detector and the operation of the screw pump 60 is stopped. As other methods, conventionally known techniques such as a method of detecting the reflection density of the toner image on the photosensitive member and controlling the same toner replenishment amount can be used.

  The sucked toner falls from the toner transport pipe 43Y into the developing device 5Y, and is further transferred to the developing unit by a stirring screw (not shown). When the two-component development method is used, the toner replenished during the transfer process (sucked toner) is agitated and mixed with the developer in the developing device to obtain a uniform agent concentration and an appropriate charge amount.

  Here, the rotor 61 rotates while being in local contact with the stator 62 biting. When the rotor 61 is made of a metal material and the stator 62 is made of a rubber material, a large frictional force is generated when the toner in the pump is insufficient due to the surface property. The toner shortage occurs when powder toner is clogged or the toner cartridge runs out of toner.

  In such a case, heat is generated by friction between the rotor 61 and the stator 62, and the powder toner having low heat resistance is damaged. Although the degree varies depending on the degree of heat, when the aggregate is large, the image is adversely affected, and when the heat is high, the stator and the rotor are fixed and the pump becomes non-rotatable. Further, when the toner powder is completely absent, the stator and the rotor may be abruptly worn and the function as a pump may not be achieved. In this example, the clutch 66 is disposed as one of means for preventing the pump from being driven at the time of high torque due to powder shortage. However, the transmittable torque of the clutch 66 has a large variation in parts, and it is difficult to control it uniformly. In addition, when the drive transmission is controlled by the transmittable torque of the clutch 66, the clutch 66 generates heat, and the heat may be transmitted to the powder to damage the powder.

  Therefore, in this example, a torque limiter 68 is disposed between the screw pump 60 and the motor 67. In the screw pump 60 in this embodiment, the torque varies from 0.06 to 0.22 N · m depending on the characteristics of the powder toner. In this example, the set torque value of the torque limiter 68 is set to 0.24 Nm so that all toners can be used in common. Since the torque when the toner is stuck to the stator 62 and the rotor 61 and cannot be rotated is 0.25 to 0.3 N · m, the rotation of the screw pump 60 is stopped by the torque limiter 68 before reaching this state. it can. The set torque value of the torque limiter 68 is confirmed in advance by an experiment or the like using a new toner and a new screw pump 60 in advance.

  Further, a torque (in this case, 0.25 Nm) at which a developer such as toner of a pump not provided with a torque limiter is fixed to the stator / rotor and cannot be rotated is obtained by an experiment or the like. You may make it take the value between.

  In the above example, since the initial drive torque value is 0.22 Nm, 0.24 Nm is set as a torque value at which the torque limiter is operated with a margin from the confirmed initial drive torque value.

  Also, depending on the performance of the motor, if the screw pump that does not have a torque limiter is not able to be driven due to sticking, etc., the torque limiter value can be set to the point where it can not be driven when the torque is much larger than the initial drive torque. In other words, the motor may continue to drive while a certain amount of load is applied even though the fixation has started. Continuing to use the motor while the load is applied also shortens the life of the motor.In addition, if the motor is continuously driven, the stator and rotor tend to wear down and the torque tends to decrease. In such a case, it is preferable to set the torque limit with a slight margin based on the initial drive torque value.

  The above description relates to the case of conveying and supplying new toner used in an image forming apparatus such as a copying machine, among other powders. By the way, in order to satisfy various demands such as environmental problems and resource recycling in recent years, various toner recycling mechanisms for returning the collected residual toner to the developing device and recycling it as a developer have been proposed. The recycled toner tends to deteriorate and become difficult to flow, and the torque tends to increase. For this reason, the powder pump, the powder replenishing device, and the image forming apparatus of the present invention can target these recycled toners.

  Further, in this example, the control device 110 performs drive control based on monitoring the number of rotations of the motor 67 by the rotary encoder encoder 69. That is, as described above, in this example, the rotary encoder encoder 69 that monitors the rotational drive of the motor drive shaft 67a is disposed downstream of the torque limiter 68, and the rotational speed of the motor 67 is monitored.

  In this example, the control device 110 monitors the stop state of the motor 67 from the rotational speed of the rotary encoder 69 and performs the following control.

  That is, when the motor drive shaft 67a on the downstream side of the torque limiter 68 is not rotating despite the motor 67 being driven, the drive of the motor drive shaft 67a is temporarily stopped and the drive is started again. Here, the control device 110 includes a counting unit that counts the number of times one cycle from detection to stop is performed.

  When the count means counts a predetermined number of times (for example, 3 times), the control device 110 performs control so that the motor 67 is not driven and the image is displayed even if the driving conditions of the motor 67 are met. A warning is displayed by the display means of the forming apparatus main body. By performing such control, in the case where temporary sticking occurs in the pump, such as when it has not been used for a long period of time, the motor drive is tried until a predetermined number of times (three times) until an abnormality is determined. Thus, it is possible to operate without making an abnormality determination in a temporary torque increase.

  If an abnormality has actually occurred due to sticking, depletion, or the like, the motor is not recovered when the motor is driven a predetermined number of times, so that an abnormality is notified.

1 is an overall configuration diagram illustrating a printer as an image forming apparatus. FIG. 3 is an enlarged view showing an image forming unit of the image forming apparatus. FIG. 3 is a schematic diagram illustrating a toner supply path of the image forming apparatus. 1 is a schematic diagram illustrating a configuration of a toner supply device according to an embodiment.

Explanation of symbols

1Y, 1M, 1C, 1K Photosensitive drum 2Y Cleaning unit 2a Cleaning blade 4Y Charging unit 5Y Developing devices 6Y, 6M, 6C, 6K Image forming unit 7 Exposure device 8 Intermediate transfer belts 9Y, 9M, 9C, 9K Primary transfer bias Roller 10 Intermediate transfer cleaning unit 12 Secondary transfer backup roller 13 Cleaning backup roller 14 Tension roller 15 Intermediate transfer unit 19 Secondary transfer roller 20 Fixing unit 26 Paper feed unit 27 Paper feed roller 28 Registration roller pair 29 Paper discharge roller pair 30 Stack Section 31 Toner container storage section 32Y, 32M, 32C, 32K Toner container 33Y Container body 34Y Holding section 36 Suction port 43Y Toner transport pipe 51Y Developing roller 52Y Doctor blade 53Y, 54Y Developer storage section 55Y Conveyance screw 56Y Concentration detection Sensor 59 Toner supply device 60 Screw pump 61 Rotor 62 Stator 63 Universal joint 64 Drive shaft 65 Case 66 Clutch 66a Input gear 66b Drive gear 67 Motor 67a Motor drive shaft 68 Torque limiter 69 Rotary encoder encoder 70 Nozzle 71 Tube 100 Device main body 110 Control apparatus

Claims (8)

A stator provided with a female screw hole and a male screw rotor that is rotationally driven by a drive shaft that is disposed in the spiral hole and connected to a drive source, and conveys powder from the suction port to the conveyance path In the suction type single-shaft eccentric screw pump,
A suction type single-shaft eccentric screw pump comprising a torque limiter between the drive shaft and the drive source.   The suction type single-shaft eccentric screw pump according to claim 1, further comprising a clutch between the drive shaft and the drive source.   The suction type single-shaft eccentric screw pump according to claim 1 or 2, wherein a set torque value of the torque limiter is set to be substantially the same as an initial drive torque value of the pump.   4. The suction type uniaxial eccentric according to claim 1, further comprising stop detecting means for detecting a rotation state of the drive shaft and generating a rotation stop signal when the drive shaft stops. Screw pump.   5. The suction-type single-axis eccentricity according to claim 4, further comprising drive control means for calculating a rotation stop signal corresponding to the operation of the drive source and performing drive control of the drive source based on the coefficient value. Screw pump.   The suction type single-shaft eccentric screw pump according to claim 4, wherein the control means does not drive the driving means when a coefficient value of the rotation stop signal exceeds a predetermined value.   A powder toner conveying device comprising the suction type uniaxial eccentric screw pump according to any one of claims 1 to 6. An image forming apparatus comprising the powder toner conveying device according to claim 7.