JP3667925B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to electrophotographic image forming apparatuses such as printers, facsimiles, and copiers using a two-component developer or a one-component developer, and in particular, powders of toner and developer (hereinafter collectively referred to as toner). The present invention also relates to a powder transfer section of an image forming apparatus having a means for transferring.
[0002]
[Prior art]
2. Description of the Related Art In an electrophotographic image forming apparatus, a configuration is known in which a toner supply device is provided separately from the developing device in order to supply toner to a developing unit of the developing device. The technology relating to this toner supply device is as follows: (1) In a developing device using a two-component developer, a toner storage section and a developing section of the toner supply apparatus are connected by a pipe, and a coil screw provided inside the pipe (2) A toner storage container is provided at a position close to the developing unit, and the toner storage container mainly by gravity. There is a technique for supplying toner to the developing unit.
[0003]
Also, in the image forming apparatus, a cleaning device that cleans and collects residual toner after image formation (residual toner on the image forming body such as a photoconductor and an intermediate transfer body and residual toner on a transfer conveyance body such as a transfer belt). 2. Description of the Related Art There is known a recovered toner transfer device that transfers recovered toner to a recovered toner storage unit or a developing device provided separately. As a technique relating to the collected toner transfer device, (1) a collected toner discharge portion of the cleaning device and a collected toner storage means provided separately from the cleaning device are connected by a pipe, and a coil screw provided inside the pipe (Or coil recovery spring) technology for transferring the recovered toner to the recovered toner storage means (Japanese Patent Laid-Open No. 56-46281, etc.), (2) recovered toner storage at a position close to the recovered toner discharge portion of the cleaning device And a technique for transferring the collected toner to the collected toner storage means mainly by gravity (Japanese Patent Laid-Open No. 58-54369).
[0004]
As described above, the powder transfer mechanism used in the conventional toner supply device and the recovered toner transfer device includes a pipe connecting between the devices, a coil screw provided inside the pipe, or a natural drop. A transfer means for transferring toner by using the toner has been used. In these transfer mechanisms, it is necessary to attach the coil screw to the very vicinity of each device, and in order to ensure the reliable rotation of the coil screw, it is preferable to perform linear transfer, at least curved transfer with a large curvature radius. It is necessary to secure the transfer path (in other words, a bent transfer path is not suitable), and there are various restrictions such that it is desirable to install the transfer destination at a lower position than the transfer source. Furthermore, in the conventional powder transfer mechanism, since the friction load with the pipe is large, it is difficult to reduce the load of the coil screw or perform long-distance transfer, and the components become large and the device configuration is complicated. In addition, there are problems such as difficulty in ensuring durability and difficulty in operability during apparatus maintenance. In addition, due to restrictions on the mounting position of the powder transfer mechanism, problems such as an increase in size and complexity of the image forming apparatus and an increase in the cost of the main body have arisen.
[0005]
In order to solve the above problem, the applicant of the present invention has proposed a rotor that moves toner in the axial direction by rotating (spinning) as a toner transfer mechanism that enables reliable toner transfer with a simple and low-cost apparatus configuration. And a screw pump means (powder pump) having a rotating space for the rotor and a stator in contact with the rotor, and the toner moving by the screw pump means flowing A toner transfer device including an air supply means for supplying air to the screw pump means, a toner transfer means from the toner storage means to the development means, a recovery toner storage section or a development device from the cleaning device A technique used as a means for transferring toner to a toner is proposed (Japanese Patent Laid-Open No. 7-219329, Japanese Patent Application No. 7) Nos. 89697, Japanese Patent Application No. Hei 7-339182, Japanese Patent Application No. 8-36111, Japanese Patent Application No. 8-3612, etc.).
[0006]
In the toner transfer device as described above, by using the screw pump means and the air supply means for supplying air to the screw pump means, the collected toner collected by the cleaning device is mixed with air to the developing device. Since it can be transferred, flexible pipes can be used in the transfer path, and the degree of freedom of the transfer path is large and the transfer load is small, so reliable transfer of recovered toner is possible with a simple and low-cost device configuration. It can be.
[0007]
[Problems to be solved by the invention]
By the way, in the image forming apparatus using the screw pump means for toner transfer, the toner collected by the cleaning device is in a certain warming state due to heat from the fixing device and other components in the image forming apparatus. . When such recovered toner enters the screw pump means from the cleaning device, the temperature of the rotor of the screw pump means is further increased due to frictional heat, and the temperature is highest near the outlet of the screw pump means. found. If the conveying operation of the screw pump means is stopped for a long time in such a state, the collected toner near the outlet is hardened, which may cause the lock of the screw pump means and the overflow of the collected toner due to the lock. In addition, a conveyance failure may occur before that due to fluctuations in the drive load of the screw pump. Continued driving without noticing such an abnormality may cause toner scattering due to poor conveyance or damage to the machine.
[0008]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image forming apparatus that can prevent the occurrence of an abnormality due to a temperature rise of a screw pump and prevent a machine from being damaged.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a rotor that moves powder in the axial direction by rotating, and a stator that is disposed so as to wrap around the rotor, has a rotation space for the rotor, and contacts and engages with the rotor. In the image forming apparatus comprising the screw pump means and the air supply means for flowing the powder moving by the screw pump means in a diffused state, a means for detecting the temperature near the outlet of the screw pump means is provided, When the drive of the main body is stopped, when the temperature detected by the temperature detection means is equal to or higher than a predetermined temperature, the forward rotation operation or reverse rotation operation of the rotor is started so that the powder does not stay near the outlet. To do.
[0010]
It is preferable that the rotational drive of the rotor is independent from the main body drive. It is also preferable that the forward / reverse operation of the rotor is performed in a state where the rotational speed is lower than the rotational speed during the forward rotation of the rotor while the main body is being driven. It is preferable to provide a powder storage part upstream of the powder receiving part of the screw pump means.
[0011]
Further, a screw pump means having a rotor that moves powder in the axial direction by rotating, and a stator that is disposed so as to wrap around the rotor and that has a rotation space for the rotor and that is in contact engagement with the rotor; In an image forming apparatus comprising an air supply means for causing the powder moving by the screw pump means to flow in a diffused state, a temperature detection means is disposed at or near the screw pump means, and the temperature detection means The detected temperature is a predetermined first temperature (T ₁ In the case of the above, the above problem can be solved even if the rotational speed of the screw pump means is switched to the slower one.
[0012]
It is preferable that the image forming operation is prohibited when the temperature detected by the temperature detecting means is equal to or higher than a predetermined first temperature. Further, it is preferable that the prohibition of the image forming operation is canceled when the detected temperature is equal to or lower than a predetermined second temperature. And when the detected temperature is below predetermined 2nd temperature, the rotation speed of a screw pump means is switched to an earlier one.
[0013]
It is also preferable to provide a cooling means for cooling the screw pump means.
[0014]
It is convenient to activate the cooling operation when the temperature detected by the temperature detecting means is equal to or higher than a predetermined first temperature. Further, when the detected temperature is equal to or lower than the predetermined second temperature, the cooling operation is stopped. When the machine is stopped, the cooling means may be driven independently of the main body drive based on the detection result by the temperature detecting means.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on the illustrated examples.
An image forming apparatus according to the present invention includes an image carrier such as a photosensitive member, a charging device disposed around the image carrier, an exposure unit (an original image exposure device or an optical writing device corresponding to an image signal), It is equipped with a developing device, a transfer device, a cleaning device, a static eliminator, etc., and forms a toner image on a transfer material such as recording paper through an image forming process by a known electrophotographic method of charging, exposure, development, transfer, In the fixing device, a toner image is fixed on a transfer material to obtain a desired image. Such a configuration is widely known and is not shown for simplicity.
[0016]
This embodiment shows an image forming apparatus configured to collect toner remaining on an image carrier after transfer with a cleaning device, and transfer the collected toner to a waste toner tank with a recovery toner transfer device. The configuration of the collected toner transfer unit will be described in detail below, but the embodiment is an example embodying the present invention and does not limit the technical scope of the present invention. .
[0017]
In FIG. 1, the toner collected by the photoconductor cleaning unit 300 is transferred from a collected toner discharge unit 301 provided in the unit 300 to a toner guide member 321 of a collected toner transfer unit 320 that engages with the discharge unit. . The toner guide member 321 serves as a toner transfer path for sending toner from the photoreceptor cleaning unit 300 to the collected toner transfer powder pump 330. Reference numeral 110 in the drawing denotes a structure of the main body of the image forming apparatus. The support member 339 of the photoconductor cleaning unit 300 and other image forming members, the support member 339 of the collected toner transfer unit 320, and the like are included in the structure 110. It is attached.
[0018]
In FIG. 2 showing the internal structure of the main part of the collected toner transfer unit 320 shown in FIG. 1, a conventionally known screw pump called “Mono pump” is used as the powder pump 330. The powder pump includes a spiral rod-shaped rotor 331 and a stateer 332 that is disposed so as to wrap around the rotor 331 and has a rotation space for the rotor and is in partial contact with the rotor. The rotor 331 is coaxially engaged with one end of a lateral conveying screw 333 for sending the collected toner discharged from the discharge unit of the cleaning unit from the toner guide member 321 to the powder pump. The other end of the lateral conveying screw 333 is supported by a bearing 335 that passes through a seal member 334 and is fixed to a support member 339, and further includes a driven gear 336 outside the hopper. A hopper 337 in which the lateral conveying screw 333 is disposed is supported by a support member 339 and is connected to the toner guide member 321 to constitute a recovered toner transfer path to the powder pump 330.
[0019]
Further, as shown in FIG. 3 illustrating the structure of the collected toner discharge portion 301 of the photosensitive member cleaning unit 300 and the toner guide member 321 of the collected toner transfer unit 320 shown in FIG. The collected toner discharge unit 301 of the cleaning unit 300 is engaged, and a collected toner discharge member 302 such as a coil screw is built in the collected toner discharge unit 301, and the toner collected by the photoconductor cleaning unit 300 is collected. It is used for transfer to the toner guide member 321. The collected toner transferred to the toner guide member 321 falls into the hopper 337 through the toner guide member 321 as recognized in FIG.
[0020]
The powder pump 330 is connected to the hopper 337 side by a holder 338. The drive motor 340 is attached to the support member 339 and has a drive gear 341 at the end of the drive shaft. The drive gear 341 is engaged with the driven gear 336 described above. Accordingly, when the drive motor 340 is driven to rotate, the lateral conveying screw 333 and the rotor 331 are rotated via the driving gear 341 and the driven gear 336, and the collected toner transferred into the hopper 337 via the toner guide member 321 is laterally conveyed. It is transferred to the powder pump 330 by a screw 333. Here, the drive motor 340 is used as the drive means. However, when the operation timing of the screw pump can be synchronized with the main body drive (drive of the photosensitive member, cleaning, etc.), the driven gear 336 is provided via a gear or the like. Can be connected to the main body drive, and the drive motor 340 can be omitted.
[0021]
As described above, the powder pump (Mono pump) 330 includes the rotor 331 connected to the drive motor 340 via the lateral conveying screw 333, the stateer 332 made of an elastic material such as rubber and surrounding the rotor 331, and the stateer. A holder 338 for holding 332 and the like are provided. There is a gap of about 1 mm between the outer peripheral surface of the stateer 332 and the inner peripheral surface of the holder 338, and this gap communicates with the collected toner passage (ejection unit) 350, and is connected to the collected toner passage 350 through the gap. An air supply port 351 is provided so as to blow. The air supply port 351 communicates with the collected toner passage 350 at the inner end thereof, while the outside thereof communicates with the air discharge port 361 and the air supply pipe 362 provided in the air pump 360 as air supply means as can be recognized in FIG. It communicates through. When the air pump 360 is activated, air is blown into the collected toner through the air supply port 351 at a blowing rate of about 0.5 to 1 liter / minute. As a result, fluidization of the collected toner exiting from the passage 350 of the powder pump 330 is promoted, and the collected toner is reliably transferred by the powder pump 330. Then, the collected toner that has passed through the powder pump 330 is transferred to the waste toner tank 200 shown in FIG. 4 via the collected toner transfer pipe 380.
[0022]
FIG. 4 is a perspective view showing a collected toner guide portion to the waste toner tank. The collected toner transferred from the photoconductor cleaning unit 300 through the collected toner transfer pipe 380 by the powder pump 330 is introduced from the inlet 260 of the toner collecting device 250 installed at the upper part of the waste toner tank 200, and the waste toner. It is sent into the tank 200. The collected toner is mixed with air during the transfer, but since the air is discharged to the outside by the filter 261 provided at the upper part of the toner collecting device 250, only the collected toner is collected, and the waste toner is collected by gravity. It falls into the tank 200 and is stored.
[0023]
Here, as shown in FIGS. 1 and 2, the present invention is characterized in that the powder pump 330 has a thermistor 400 for temperature detection. In the illustrated example, the thermistor 400 is provided outside the holder 338 of the powder pump 330. However, according to the results of experiments by the present inventors, the portion A near the outlet of the powder pump 330 has the highest temperature. Since it has been found that the toner is likely to be solidified, it is convenient to install the thermistor 400 in the portion.
[0024]
By driving the powder pump independently of the main body drive, the powder pump is normally rotated forward to transfer the collected toner to the waste toner tank via the collected toner transfer pipe 380, and the flow shown in FIG. As shown, the temperature Ta of the powder pump 330 is detected by the thermistor 400 when the machine is stopped (at this time, the powder pump is also stopped), and Ta ≧ T (T is the toner solidification (melting) temperature. ), The forward rotation operation is started, and after Ta <T, the forward rotation operation is continued for a time t. This is because the recovered toner in the high temperature portion is conveyed as far as possible from the portion. After that, the forward rotation is stopped. By such an operation, the toner located in the high temperature portion is conveyed outside the powder pump, and the powder pump can be prevented from being locked in the portion. Of course, waste toner is not discharged from the cleaning unit during this operation.
[0025]
Instead of the forward rotation operation when the machine is stopped, a reverse rotation operation may be performed. When the rotation is reversed as described above, the toner in the rotation space for the recovery toner passage and the rotor is returned to the hopper side in the direction opposite to the recovery toner transport direction from the recovery toner transfer pipe 380 to the waste toner tank. This reversal operation prevents new waste toner from entering the collected toner passage and the rotor rotation space, and it is possible to quickly remove the collected toner in the high temperature part and avoid the powder pump from being locked quickly. It will be possible. However, when such a reverse operation is performed, the collected toner in the hopper is also conveyed in the reverse direction via the toner guide member 321, so that a hopper 337 ′ having a depth is attached as shown in FIG. It is good to leave.
[0026]
In the above forward / reverse operation, the rotation can be slowed. This makes it possible to minimize the generation of frictional heat in the rotor while transferring the recovered toner, and to enable a faster temperature drop and more reliably avoid the occurrence of powder pump locks. can do.
An example of temperature detection and image forming operation control by the thermistor 400 during image formation is shown in FIG. It is assumed that the temperature of the thermistor 400 at the start is set to 20 ° C., for example, and if it is operated as it is without temperature control, it reaches 60 ° C. at which abnormality such as toner fixation (melting) occurs in about 30 minutes. Therefore, T is set as a prohibited temperature for the image forming operation. ₁ Set = 50 ° C. Further, as the prohibition release temperature of the image forming operation, T ₂ Set = 30 ° C. Therefore, in this example, when the temperature of the thermistor 400 reaches 50 ° C., the image forming operation is stopped, and when the temperature of the thermistor 400 becomes 30 ° C. or lower, the prohibition of the image forming operation is canceled. As a result, the machine always operates at 50 ° C. or lower, and the occurrence of abnormality such as toner fixation can be avoided.
[0027]
FIG. 8 shows a block diagram of this control system. In the figure, reference numeral 410 is a ROM for storing a control program, 420 is a RAM for storing control data, and 440 is a microcomputer (μCPU) for performing calculation and controlling each part of the image forming apparatus based on the control program and control data. is there. The temperature detection thermistor 400 provided in the powder pump or in the vicinity thereof sends the temperature detection output to the microcomputer 440 via the A / D converter 450 and the input / output interface 460. The microcomputer 440 controls each part of the image forming apparatus including the main motor and the operation part according to the output of the thermistor 400, and controls the image forming operation as shown in FIG.
[0028]
Next, a collected toner transfer device according to another configuration will be described. 9 showing the recovered toner transfer device and FIG. 10 showing the internal structure of the recovery transfer unit 320, the configuration and structure of the recovery toner transfer unit 320 itself are the same as those shown in FIGS. Further, the structures of the collected toner discharge portion 301 of the photosensitive member cleaning unit 300 and the toner guide member 321 of the collected toner transfer unit 320 are the same as those shown in FIG. 3, and the configuration on the waste toner tank side is also shown in FIG. The configuration and operation are the same as those described above, and a description thereof is omitted here.
[0029]
In this embodiment, as shown in FIGS. 9 and 10, the temperature detection thermistor 400 is provided in the powder pump 330 and the cooling fan 405 for cooling the powder pump 330 is provided. Yes. In the illustrated example, the cooling fan 405 is disposed below the powder pump 330. However, if the fan can be cooled by blowing air on the holder 338 of the powder pump 330, the arrangement position is Be free.
[0030]
FIG. 11 shows an example of temperature detection by the thermistor 400 and operation control of the cooling fan 405 during image formation. It is assumed that the temperature of the thermistor 400 at the start is set to 20 ° C., for example, and if it is operated as it is without temperature control, it reaches 60 ° C. at which abnormality such as toner fixation (melting) occurs in about 30 minutes. Therefore, as the operating temperature of the cooling fan 405, T ₁ Set = 50 ° C. Further, as a stop temperature of the cooling fan 405, T ₂ Set = 30 ° C. Therefore, in this example, the operation of the cooling fan 405 is started when the temperature of the thermistor 400 becomes 50 ° C., and the operation of the cooling fan 405 is stopped when it becomes 30 ° C. or less. As a result, the machine always operates at a temperature of 50 ° C. or less, and it is possible to avoid the occurrence of abnormalities such as toner fixation, and it is possible to prevent noise and wasteful power consumption without the cooling fan continuing to operate except when necessary.
[0031]
FIG. 12 shows a block diagram of the control system. In the figure, reference numeral 410 is a ROM for storing a control program, 420 is a RAM for storing control data, and 440 is a microcomputer (μCPU) for performing calculation and controlling each part of the image forming apparatus based on the control program and control data. is there. The temperature detection thermistor 400 provided in the powder pump or in the vicinity thereof sends the temperature detection output to the microcomputer 440 via the A / D converter 450 and the input / output interface 460. The microcomputer 440 controls the driver of the cooling fan 405 according to the output of the thermistor 400, and controls the operation of the cooling fan 405 as shown in FIG.
[0032]
In the example in FIG. 9 and subsequent figures, the temperature control during the image forming operation is performed by turning the cooling fan 405 on and off. However, when the machine is stopped, the powder pump 330, particularly the forward / reverse rotation of the rotor, is detected based on the temperature detection. In the first example of avoiding the lock of the powder pump, the cooling fan 405 can be driven during the forward / reverse operation so as to efficiently lower the temperature of the powder pump portion.
[0033]
In the collected toner transfer device that performs another control, the control will be described. This controls the number of rotations of the driving means of the rotor based on the result of temperature detection. In the following example, the number of revolutions is switched in two steps, but it is not limited to this control, and the number of revolutions is switched steplessly in multiple steps as needed or in accordance with the temperature. Of course it is good. FIG. 13 shows an example of temperature detection by the thermistor 400 and operation control of the rotor driving means 340 during image formation. It is assumed that the temperature of the thermistor 400 at the start is set to 20 ° C., for example, and if it is operated as it is without temperature control, it reaches 60 ° C. at which abnormality such as toner fixation (melting) occurs in about 30 minutes. Therefore, as the first rotation switching (early → slow) temperature, T ₁ Set = 50 ° C. As the second rotation switching (slow → early) temperature, T ₂ Set = 30 ° C. Therefore, in this example, when the temperature of the thermistor 400 reaches 50 ° C., the rotational speed of the driving means decreases, and when the temperature of the thermistor 400 reaches 30 ° C. or lower, the rotational speed is increased again. As a result, the machine always operates at a temperature of 50 ° C. or less, and it is possible to avoid the occurrence of abnormality such as toner sticking, and to effectively utilize the performance of the powder pump.
[0034]
FIG. 14 shows a block diagram of the control system. In the figure, reference numeral 410 is a ROM for storing a control program, 420 is a RAM for storing control data, and 440 is a microcomputer (μCPU) for performing calculation and controlling each part of the image forming apparatus based on the control program and control data. is there. The temperature detection thermistor 400 provided in the powder pump or in the vicinity thereof sends the temperature detection output to the microcomputer 440 via the A / D converter 450 and the input / output interface 460. The microcomputer 440 controls the driver of the powder pump drive motor 340 based on the output of the thermistor 400 to switch and control the rotational speed of the rotor as shown in FIG.
[0035]
【The invention's effect】
According to the image forming apparatus of the first aspect, there is provided means for detecting the temperature in the vicinity of the outlet where the temperature in the screw pump means can be highest when the machine is stopped, and when the main body drive is stopped, the temperature detecting means When the detected temperature is equal to or higher than a predetermined temperature, the forward rotation operation or the reverse rotation operation of the rotor is started so that the powder does not stay near the outlet, so that unnecessary rotation operation is omitted, or It is possible to perform as many rotational operations as necessary, and to efficiently prevent locking by the means or problems associated therewith.
[0036]
By making the rotational drive of the rotor independent from the main body drive, it is possible to avoid supplying powder into the screw pump means. If the forward / reverse operation of the rotor is performed in a state lower than the rotational speed during the forward rotation of the rotor while the main body is being driven, the generation of frictional heat can be suppressed and the temperature can be lowered more quickly. If a powder storage part is provided upstream of the powder receiving part of the screw pump means, it is possible to avoid overflow of powder during reverse rotation.
[0037]
According to the image forming apparatus of the present invention, the temperature detecting means is disposed at or near the screw pump means, and the rotational speed of the screw pump is controlled based on the detection result. Since the screw pump rotation speed is switched to the slower one when the temperature is higher than the temperature, poor conveyance due to fluctuations in the drive load of the screw pump means can be avoided, and the performance of the screw pump means can be effectively achieved without any mechanical abnormality. It can also be used to prevent toner scattering and machine damage due to poor conveyance.
[0038]
By prohibiting the image forming operation when the temperature detected by the temperature detecting means is equal to or higher than a predetermined first temperature, the operation can be stopped before the screw pump means becomes abnormal. When the detected temperature is equal to or lower than the predetermined second temperature, the operation of the screw pump unit can be controlled within the temperature range where no abnormality occurs by canceling the prohibition of the image forming operation.
[0039]
Furthermore, by providing the cooling means for cooling the screw pump means, it is possible to quickly avoid the occurrence of abnormality due to the temperature rise of the screw pump means.
[0040]
When the temperature detected by the temperature detecting means is equal to or higher than the predetermined first temperature, the cooling operation is started. When the temperature is equal to or lower than the predetermined second temperature, the cooling operation is stopped. The operation can be limited only when necessary, and the side effects (noise and power consumption) due to the cooling operation can be minimized while suppressing the temperature rise. If the cooling means is driven independently of the main body drive based on the detection result by the temperature detecting means when the machine is stopped, the temperature can be lowered efficiently.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a configuration example of a collected toner transfer device in an image forming apparatus according to the present invention.
FIG. 2 is a cross-sectional view of the main part of the recovered toner transfer device showing the structure of the recovered toner transfer unit shown in FIG.
3 is a cross-sectional view of an essential part showing a structural example of a collected toner discharge portion of the photosensitive member cleaning unit and a toner guide member of the collected toner transfer unit shown in FIG. 1;
FIG. 4 is a perspective view illustrating a collected toner discharge unit to a waste toner tank.
FIG. 5 is a diagram showing a flow for controlling the forward rotation operation of the powder pump when the drive of the machine is stopped.
FIG. 6 is a cross-sectional view of a principal part of the collected toner transfer device showing a hopper suitable for the reverse rotation operation of the powder pump when the machine is stopped.
FIG. 7 is a diagram illustrating an example of temperature detection and image forming operation control by a thermistor that is a temperature detection unit.
FIG. 8 is a block diagram illustrating an example of a control system of the image forming apparatus including the collected toner transfer device illustrated in FIG.
FIG. 9 is a perspective view of a collected toner transfer device showing an example according to another configuration.
10 is a cross-sectional view of the main part of the recovered toner transfer device showing the structure of the recovered toner transfer unit shown in FIG. 9;
11 is a diagram showing an example of temperature detection by a thermistor and operation control of a cooling fan in the apparatus shown in FIG.
12 is a block diagram illustrating an example of a control system of an image forming apparatus including the collected toner transfer device illustrated in FIG.
FIG. 13 is a diagram illustrating an example of temperature detection by a thermistor and drive switching control of a powder pump in a collected toner transfer device according to still another configuration.
14 is a block diagram illustrating an example of a control system of an image forming apparatus including the collected toner transfer device illustrated in FIG.
[Explanation of symbols]
200 Waste toner tank
300 Photoconductor cleaning unit
320 Collected toner transfer unit
321 Toner guide member
330 Powder pump (screw pump means)
331 rotor
332 Stater
333 Horizontal conveying screw
337 Hopper
350 Collected toner passage
360 Air pump (air supply means)
380 Collected toner transfer pipe
400 thermistor (temperature detection means)
405 Cooling fan (cooling means)

Claims (12)

A screw pump means having a rotor for moving powder in the axial direction by rotation, a stator disposed so as to wrap around the rotor, a rotation space for the rotor, and a contactor engaging with the rotor; and the screw In an image forming apparatus comprising an air supply means for causing powder that moves by a pump means to flow in a diffuse state,
A means for detecting the temperature in the vicinity of the outlet of the screw pump means is provided, and when the temperature detected by the temperature detecting means is equal to or higher than a predetermined temperature when the main body is stopped, the rotor is rotated forward or reverse An image forming apparatus characterized in that the apparatus is configured so as to prevent powder from staying in the vicinity of the outlet.   The image forming apparatus according to claim 1, wherein the rotational drive of the rotor is independent from the main body drive.   The image forming apparatus according to claim 1, wherein the forward / reverse operation of the rotor is performed in a state lower than a rotational speed at the time of forward rotation of the rotor while the main body is being driven.   The image forming apparatus according to claim 1, further comprising a powder storage unit upstream of the powder receiving unit of the screw pump unit. A screw pump means having a rotor for moving powder in the axial direction by rotation, a stator disposed so as to wrap around the rotor, a rotation space for the rotor, and a contactor engaging with the rotor; and the screw In an image forming apparatus comprising an air supply means for causing powder that moves by a pump means to flow in a diffuse state,
When the temperature detecting means is disposed at or near the screw pump means, and the temperature detected by the temperature detecting means is equal to or higher than a predetermined first temperature (T ₁ ), the rotational speed of the screw pump means is set. An image forming apparatus that switches to a slower one. The image forming apparatus according to claim 5, wherein the image forming operation is prohibited when the temperature detected by the temperature detecting unit is equal to or higher than a predetermined first temperature (T ₁ ). The image forming apparatus according to claim 5, wherein the prohibition of the image forming operation is canceled when the temperature detected by the temperature detecting unit is equal to or lower than a predetermined second temperature (T ₂ ). 8. The image formation according to claim 7, wherein when the temperature detected by the temperature detecting means is equal to or lower than a predetermined second temperature (T ₂ ), the rotational speed of the screw pump means is switched to an earlier one. apparatus.   6. The image forming apparatus according to claim 5, further comprising cooling means for cooling the screw pump means. 10. The image forming apparatus according to claim 9, wherein the cooling operation is activated when the temperature detected by the temperature detection unit is equal to or higher than a predetermined first temperature (T ₁ ). The image forming apparatus according to claim 10, wherein the cooling operation is stopped when the temperature detected by the temperature detection unit is equal to or lower than a predetermined second temperature (T ₂ ).   The image forming apparatus according to claim 9, wherein when the machine is stopped, the cooling unit is driven independently of the main body drive based on a detection result by the temperature detection unit.

Images