JPH1173079A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the life of a screw pump by providing a toner reservoir for accumulating the recovered toner on the upstream side in the toner transfer direction of a toner transfer means, and operating the toner transfer means when the recovered toner in the toner reservoir reaches a designated amount. SOLUTION: Residual toner remaining on a photoreceptor is scraped from a photoreceptor by a cleaning blade or a brush roller of a cleaning means and transported to an outlet 12 of a toner transfer device 20 by a coil. The recovered toner sent to the outlet 12 drops into a toner guide by its dead load to be accumulated in a toner reservoir 21. When the recovered toner accumulated in the toner reservoir part 21 reaches a designated amount, a toner quantity detecting means 15 outputs a detection signal to a control part 14. While a screw pump 30 and an air pump 40 of the toner transfer device 20 are normally stopped, when the control part 14 receives a detection signal, a driving motor 25 and the air pump 40 controlled to operate by the control part 14 are operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital copying machine,
The present invention relates to an electrophotographic image forming apparatus such as a printer, a facsimile, or a multifunction peripheral thereof.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, it is possible to collect toner remaining on an image carrier or the like after a transfer step by a cleaning means, and return the collected toner to a developing means for reuse. It has already been proposed. In an image forming apparatus provided with such a toner recycling mechanism, cleaning means removes toner that has been transferred onto a photoreceptor, but has not been transferred onto a transfer-receiving body, or toner remaining on a transfer belt. And a toner transfer device for transferring the collected toner from the cleaning means to the developing means.

Conventionally, the following main methods have been known for transferring toner. (1) Connect the cleaning device and the destination with a pipe,
(2) a device in which the cleaning device and the destination portion are disposed at close upper and lower positions to transfer the toner mainly by gravity; (3) a device for rotating the toner by a coil screw provided inside the pipe; A screw pump having a rotor for moving the toner of the developer in the axial direction, a fixed stator having a passage wrapping the rotor therein and being in contact with the rotor inside the passage, and a screw pump comprising: A device that uses an air supply unit that supplies air for fluidizing a moving developer to transfer a mixture of toner and air through a flexible pipe (Japanese Patent Laid-Open No. 7-219).
329), and the like.

However, in the transfer method (1), in order to ensure the reliable rotation of the coil screw, it is desirable to secure a toner transfer path so as to enable a linear transfer or a large curved transfer. (The bent transfer path is not allowed.) Furthermore, in this toner transfer method, the friction load between the coil screw and the pipe is very large,
The rotational driving torque of the coil screw is increased, making it difficult to transfer the collected toner over a long distance, and giving a stress to the transferred toner to cause agglomeration, heat fusion, and the like.

In the transfer method (2), although the transfer of the toner can be performed relatively easily, it is necessary to arrange the collected toner storage means or the developing device substantially integrally with the cleaning device. Due to restrictions and restrictions on the amount of stored toner, the types of image forming apparatuses that can be mounted are limited to low-speed machines (or copiers and printers for users who use a small amount of copies and prints).

In the transfer method (3), the stored toner and the collected toner can be transferred via a flexible pipe or the like, so that the installation positions of the toner storage unit and the toner collection unit are not restricted at all. There is an advantage that the transfer of the toner can be reliably performed with a simple configuration. In addition, a toner transfer device using a screw pump can stably transfer the toner by transferring the mixture in a state of being mixed with air by an air supply unit in a fluidized state. Aggregation and thermal fusion of the transferred toner are less likely to occur without applying more stress.

[0007] Under these circumstances, it can be seen that the toner transfer method using a screw pump is particularly excellent.
This screw pump is a single-shaft eccentric screw pump (commonly called a mono pump) composed of a female screw type stator having a double pitch spiral groove therein and a male screw type rotor rotatably fitted in the stator.

[0008]

In a toner transfer device using a screw pump, a metal rotor inserted into the stator rotates while slidingly contacting the stator. The inner diameter gradually increases with time. When the inner diameter of the stator increases and the amount of bite between the rotor and the rotor decreases, a backflow phenomenon occurs in which the air supplied after the discharge of the screw pump passes through the gap between the stator and the rotor and exits to the inlet side of the pump. In some cases, when such a backflow phenomenon occurs, the transfer of the powder is hindered. Therefore, it has been determined that the screw pump has reached the end of its life.

[0009] Since the operating period of the screw pump which reaches the end of its life in this way is considerably short, there is a problem that it is difficult to balance the life of the other parts compared with the life of other parts, and it is difficult to put the screw pump to practical use.

In order to prolong the service life of the screw pump, it is conceivable to increase the amount of bite between the rotor and the stator in advance. In this case, however, due to the rotational friction between the rotor and the stator, the temperature rise during continuous operation causes blocking of the collected toner. In addition, the quality of the image formed due to the deterioration of the toner and the quality of the collected toner conveyed are deteriorated. Furthermore, during the continuous operation of the screw pump, since the air supplied from the air pump is continuously fed into the developing means, a problem of toner scattering due to an increase in the internal pressure in the developing means also occurs.

The present invention has been made in consideration of the above circumstances, and has as its object to provide an image forming apparatus that can extend the life of a screw pump and is less likely to cause toner deterioration and toner scattering in a developing unit. .

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a method in which toner removed / recovered by a cleaning means is combined with a gas flow by the operation of a toner transfer means having a screw pump and an air supply means. In the image forming apparatus that transfers the toner as a mixture to the toner destination, a toner reservoir for storing the collected toner is provided upstream of the toner transporting unit in the toner transport direction, and when the amount of the collected toner in the toner reservoir reaches a predetermined amount. , Wherein the toner transfer means is operated.

According to the present invention, a toner amount detecting means is provided in the toner reservoir, and the toner transferring means is operated by a signal from the toner amount detecting means which detects that the collected toner has reached a predetermined amount. And it is effective.

Further, according to the present invention, when the operation of the toner transfer means is stopped after being continuously performed for a predetermined time,
It is effective. Furthermore, the present invention is effective when the operation of the screw pump is stopped when the predetermined time period is reached after the operation of the toner transfer unit is started, and the operation of the air supply unit is stopped later.

Still further, according to the present invention, when the toner amount detecting means is disposed near the toner intake port of the screw pump and the amount of the toner intake port substantially filled with the collected toner is detected as a predetermined amount, the effect is obtained. It is a target.

Still further, according to the present invention, there is provided a control unit for judging occurrence of abnormal transfer of the collected toner based on a detection signal of the toner amount detecting means after the toner transferring means stops the operation of transferring the collected toner. It is effective if provided.

Further, the present invention is effective when the control unit has a warning unit for issuing a warning when it is determined that the collected toner is abnormally transferred. Further, in order to achieve the above object, the present invention provides a method in which the toner removed / recovered by the cleaning unit is supplied to the toner destination as a mixture with a gas flow by the operation of a toner transfer unit having a screw pump and an air supply unit. In the transferring image forming apparatus, a toner reservoir is provided on the upstream side of the toner transport unit in the toner transport direction, and when the toner in the toner reservoir reaches a predetermined amount, the toner transport unit is operated. It is characterized by.

In the present invention, the number of image forming sheets is counted, and when the counted number reaches a predetermined number, it is considered that the collected toner in the toner reservoir reaches a predetermined amount and the toner transfer means is operated. Is effective.

Further, according to the present invention, there is provided a pixel number detecting means for detecting the number of pixels at the time of image formation, and when the number of pixels counted by the pixel number detecting means reaches a predetermined number, the collection of the toner collecting portion is performed. It is effective to operate the toner transfer means assuming that the toner has reached a predetermined amount.

Further, the present invention is effective when the toner destination to which the collected toner is transferred by the operation of the toner transferring means is a developing means. Still further, the present invention is effective when the toner destination to which the collected toner is transferred by the operation of the toner transfer unit is an agent storage unit for storing toner or developer to be transferred to the developing unit. .

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall schematic diagram showing a digital copying machine as an example of an image forming apparatus according to the present invention.

In FIG. 1, a digital copying machine uses a well-known electrophotographic system, and includes a drum-shaped photosensitive member 1 as an image bearing member inside. Arrow A around photoconductor 1
A charger 2, an exposure unit 3, a developing unit 4, a transfer unit 5,
Cleaning means 6 is provided.

Exposure means 3 includes a document table 7 on the upper surface of the copying machine.
An electrostatic latent image is formed on the photoreceptor 1 based on an image signal read by the reading means 8 from a document placed on the photosensitive member 1. The electrostatic latent image formed on the photoreceptor 1 is developed by a developing unit 4 to form a toner image, and the toner image is electrostatically transferred by a transfer unit 5 onto a transfer material fed from a paper feeding device 9. Transcribed. The transfer material on which the toner image has been transferred by the transfer is conveyed to the fixing unit 10 and after being fixed there,
Emitted outside the machine.

The toner adhered onto the photoreceptor 1 by the above-mentioned development is generally electrostatically transferred to a transfer material by the transfer means 5, but about 10% of the toner remains untransferred on the photoreceptor. This residual toner is scraped off from the photoreceptor 1 by the cleaning blade 6a and the brush roller 6b of the cleaning means 6, and the scraped-off toner is returned to the developing means 4 by a toner transfer device to be described later. Become.

On the other hand, a cleaning means 11 is also provided on the transfer belt 5a of the transfer means 5 for contacting the non-transferred portion or the non-image portion of the photosensitive member 1 and adhering toner. The toner remaining on the transfer belt 5a is scraped off by a cleaning blade 11a which is in sliding contact with the belt. The scraped toner is also transferred to the developing means 6 by a toner transfer device described later.

In the copying machine of this embodiment, the cleaning means 6 for the photosensitive member and the cleaning means 11 for the transfer belt are provided.
A toner transfer device 20 is provided for transferring the toners respectively collected to the developing means 6. The toner transfer device 20 has a screw pump 30 as a toner transfer unit and an air pump 40 as an air supply unit, and a toner reservoir 21 is provided upstream of the screw pump 30 in the toner transfer direction.

The toner reservoir 21 is formed in a hopper shape for storing a certain amount of toner, and has an upper portion communicating with the cleaning means 6 for the photosensitive member and the cleaning means 11 for the transfer belt. Outlet 1
2 and 13 are provided. In this case, the discharge port 12 of the photosensitive member cleaning unit 6 located above the transfer belt cleaning unit 11 communicates with the toner reservoir 21 via the toner guide 22. Toner reservoir 21
A transport screw 23 as a toner transport member is provided near the bottom inside the
One end of the third shaft 24 protrudes outside the toner reservoir 21, and the drive motor 25 and the gears 26, 2
It is drivingly connected via 6a. The transport screw 23 may be drivingly connected to a main motor provided in the image forming apparatus via a clutch.

The screw pump 30 includes a female screw type stator 31 having a double pitch spiral groove made of an elastic material such as rubber, and a male screw type rotor 32 rotatably fitted in the stator 31. And the rotor 32
Are connected so that the other end of the shaft 24 of the transport screw 23 coincides with the axis. Therefore, the driving motor 2
When 5 is driven to rotate, the transport screw 23 and the screw pump 30 operate. Further, the stator 31 is inserted into a holder 33 attached outside the toner reservoir 21. The holder 33 fixes the stator 31 so as to cover the periphery of the stator 31. The holder 33 has a toner discharge port 34 formed therein.
The toner discharge tube 34 is provided with a toner conveying tube 35.
Is inserted at one end. This toner transport tube 35
A flexible hose or the like can be used, and the other end can be easily connected to the developing means 4. Also, the holder 23
For example, between the inner peripheral surface of the
A gap 35 of about mm is provided, and the gap 35 communicates with the toner discharge port 34. The holder 33 is provided with an air supply port 36 communicating with the gap 35, and the air supply port 36 is connected to the air pump 40 via an air supply tube 41.

The drive motor 25 and the air pump 40
The operation of is controlled by a micro processing unit (MPU) 14 as a control unit. Also,
A toner amount detecting means 15 for detecting that a predetermined amount of collected toner has accumulated in the toner accumulation portion 21 is provided.
Is provided, and the toner amount detecting means 15
4 is connected. Incidentally, the toner amount detecting means 1 of this embodiment
Reference numeral 5 denotes a piezoelectric sensor, which detects the presence or absence of toner on the sensor surface and outputs a detection signal to the MPU 14.

Next, the movement of the toner used in the image forming process will be described with reference to FIG. The developing means 4 is a two-component developing device and includes a developing casing 50 containing a developer composed of a carrier and a toner. When the developing unit 4 forms a toner image, the toner is consumed, so that the ratio of the toner of the developer (toner density) decreases. Therefore, in order to suppress a decrease in image density, when the toner density in the developer becomes equal to or lower than a predetermined value, the toner supply roller 53 is rotated to supply toner from the toner hopper 51 and maintain the toner density in the developer. Is done. The toner concentration in the developer is measured by a magnetic permeability sensor 52 attached to the developing casing.

The toner replenished from the toner hopper 51 is stirred and frictionally charged with the carrier by the stirring member 54 in the developing means 4. The developer including the carrier and the toner is jumped up to the developing roller 56 by the paddle wheel 55, and is attracted to the peripheral surface by the magnet in the developing roller 56. The developer is conveyed by the sleeve on the outer periphery of the developing roller, and the excess is scraped off by the developing doctor 57. The toner in the developer conveyed to the photoreceptor adheres to the electrostatic latent image due to the developing bias.

The toner adhering to the photoreceptor 1 is transferred to a transfer unit 5
Is electrostatically transferred onto a transfer material, of which about 1
0% of the toner is not transferred and remains on the photoconductor. 3 and 4, the residual toner remaining on the photoconductor 1 is scraped off from the photoconductor 1 by a cleaning blade 6a and a brush roller 6b of a cleaning unit 6, and is conveyed to an outlet 12 of a toner transfer device 20 by a coil 6c. Is done. The collected toner sent to the discharge port 12 falls in the toner guide by its own weight, and is stored in the toner storage section 21. Further, the toner remaining on the transfer belt 5 a is also collected by the transfer cleaning unit 11, and this toner is also stored in the toner storage unit 21 via the discharge port 13.

When the amount of the collected toner stored in the toner storing section 21 reaches a predetermined amount, the toner amount detecting means 15 outputs a detection signal to the MPU 14. In the toner transfer device 20 according to the present invention, the operation of the screw pump 30 and the air pump 40 is normally stopped, but when the MPU 14 receives the detection signal, the drive motor 25 and the air pump whose operations are controlled by the MPU 14 40 starts operation. After the operation is started, the operation is controlled so as to be stopped when a predetermined time has elapsed. Therefore, since the screw pump 30 and the air pump 40 are operated intermittently, the collected toner collected by the cleaning unit 6 or 11 is transferred to the rotor 32 of the screw pump 30.
While maintaining the hermeticity between the toner and the stator 31, the mixture can be transferred to the developing means 4 via the toner transport tube 35 as a mixture of air and air.

In the image forming apparatus configured as described above, the screw pump 30 is operated for a predetermined time when a predetermined amount of the collected toner in the toner storage section 21 has accumulated, so that the operation can be suppressed to a necessary minimum. Thus, wear of the stator 31 can be delayed as much as possible. Therefore, the life of the screw pump 30 can be drastically extended. In addition, as compared with the case where the screw pump 30 is constantly driven, the temperature rise due to the rotational friction between the rotor 32 and the stator 31 is reduced, and the blocking and deterioration of the collected toner is reduced, so that high quality can be obtained even when the recycled toner is used. Image can be maintained.

FIG. 5 shows the screw pump 30 and the air pump 4 for the detection timing of the toner amount detecting means 15.
FIG. 7 is a diagram showing a relationship with an operation timing of 0. In the same figure, when the amount of the collected toner stored in the toner collecting section 21 reaches a predetermined amount, a signal indicating that the collected toner is present is output, whereby the air pump 40 is turned on. 0.5 second later, the screw pump 30 is turned on, that is, the rotor 32 is
N. At this time, the ON of the screw pump 30 is turned off after continuing for a predetermined time, 2 seconds in this case, and the air pump 40 is turned off after the screw pump 30 is stopped and further continued for 5 seconds. To
It is controlled by the MPU 14.

By performing such control, even if there is toner remaining in the toner transport tube 35 when the screw pump 30 is stopped, the toner is reliably transported toward the developing means by air. Therefore, the amount of toner remaining in the toner transport tube 35 is reduced, and the risk of toner clogging in the tube is avoided.

In addition, the screw pump 30
After turning off the rotation of the rotor 32, the powder pressure toner sensor as the toner amount detecting means 15 detects the level of no collected toner.

However, if abnormal recovery of the collected toner occurs as a result of the presence of an abnormality in the screw pump 30 or the like, and the collected toner does not decrease, the level of the collected toner remains, and it is determined that the recovered toner is abnormally conveyed. . At this time, the warning means 16 is operated via the MPU 14 so that a warning is displayed on a warning display panel (not shown) provided at an appropriate position of the image forming apparatus so that the operation of the image forming apparatus is stopped. Has become.

FIG. 6 is a view showing an example of the arrangement of a collected toner supply unit 60 for supplying toner to the developing means 4 and a new toner supply unit 61. The collected toner (T) is connected via the transport tube 35, and the recovered toner (T) is mixed with the gas (air) supplied from the air pump 40 by the screw pump 30 as described above.
The toner is transported in the toner transport tube 35. On the other hand, the new toner (NT) is supplied to the container 62 of the new toner supply unit 61.
Stored in advance. To supply toner to the toner hopper 51, first, the supply blade 6 of the new toner supply unit 61 is used.
3 and a new toner (NT) is supplied to the toner hopper 51.
When the sensor 64 detects that the toner has been replenished, the supply blade 65 of the collected toner supply unit 60 operates, and the collected toner (T) is supplied to the toner hopper 51. Then, the new toner (NT) and the recovered toner (T) are transported in the illustrated arrow B direction while being stirred by the transport screw 66, supplied to the developing casing 50 of the developing unit 4, and reused as recycled toner. A high quality image is formed.

The recovered toner supply unit 60 shown in FIG.
Is located downstream of the new toner supply unit 61 in the transport direction, and the transport screw 66 disposed immediately below both units 60 and 61 stirs the new toner (NT) and the recovered toner (T). While being transported in the direction of arrow B in FIG. The collected toner supply unit 60 is connected to the toner conveying tube 35, and the collected toner is supplied to the inside thereof. The MPU 14 adjusts the supply amount of the collected toner by using the screw pump 3
0 and / or by controlling the air pump 40. Further, the supply amount may be adjusted by rotating the supply blade 65.

The new toner supply amount in the new toner supply unit 61 is adjusted, for example, by controlling the rotation of the supply blade 63 so that the toner hopper 5
This is realized by adjusting the amount of new toner to be supplied into the printer.

Incidentally, it is difficult to set a predetermined amount of the toner reservoir 21 at which the screw pump 30 starts operating. The collected toner is agglomerated by being scraped off by the cleaning blade, and has a low fluidity because the temperature is increased by frictional heat. If the collected toner having poor fluidity is excessively accumulated in the toner accumulation section 21, even if the toner around the conveyance screw 23 is not conveyed, the phenomenon that the toner is cross-linked at the upper portion easily occurs. When toner cross-linking occurs in the toner reservoir 21, the toner reservoir 21 is filled to fill the toner in the cleaning device, causing a cleaning failure or causing toner to overflow from the nip portion of the photoconductor. Occur.

Therefore, in another embodiment of the present invention shown in FIG. 7, a toner amount detection sensor 15 for detecting a predetermined amount is disposed at a position for detecting a recovered toner amount at a level at which the toner intake port of the screw pump 30 is filled. ing. More specifically, the position at which the toner amount detection sensor 15 is installed is as follows: the distance a from the stator 31 is 20 to 30 mm;
In the height direction, the distance b from the upper end of the toner intake port of the stator 31 is arranged in a range of 0 to 10 mm.

If the toner amount detection sensor 15 is installed at a position filling the entrance of the screw pump 30 as described above and the collected toner is transferred by the toner detection signal of the sensor, the toner can be transferred to the entrance of the screw pump 30. Is sealed, and a load is applied to the air to be back-flowed, so that the backflow of the air can be prevented to some extent, so that the margin of the screw pump 30 is increased.

In the above-described embodiment, the toner transfer device 20 is operated by intermittently driving the toner transfer device 20 when the toner amount detecting means 15 detects that the toner in the toner reservoir 21 has reached a predetermined amount. However, the intermittent driving of the toner transfer device 20 may be performed assuming that the amount of the collected toner in the toner reservoir 21 has reached a predetermined amount.
FIGS. 7 and 8 are flowcharts showing different embodiments for intermittently driving the toner transfer device 20 on the assumption that the amount of collected toner in the toner reservoir 21 has reached a predetermined amount.

In the example shown in FIG. 7, the toner transfer device 20 is controlled so as to be intermittently driven based on the number of images formed, and the image forming apparatus is provided with a counter (not shown) for counting the number of images formed. The count number from the counter is output to the MPU 14, and it is determined whether or not the number has reached a predetermined number (step 1). When the number of image formation reaches a predetermined number, the screw pump 3
The 0 rotor 32 and the air pump 40 are turned on (step 2). Two seconds later, the rotor 32 is turned off (step 3), and after another five seconds from the stop of the drive, the air pump 40 is turned off (step 4), and the operation of transporting the collected toner ends.

In the image forming apparatus configured as described above, the average value of the amount of toner consumed in forming an image per a predetermined unit number of sheets is substantially constant, and about 10% of the amount of collected toner is collected toner. The amount of toner accumulated in the section 21 can be substantially known. Therefore, it is easy to estimate from the number of image formations that the amount of toner in the toner reservoir 21 reaches the predetermined amount, so that the toner transfer device 20 can be controlled from the number of image formations. With this configuration, as is apparent from FIG. 9 corresponding to FIG. 2, the toner amount detecting unit 15 can be eliminated, and a more inexpensive image forming apparatus can be provided.

A device that considers that the amount of collected toner in the toner reservoir 21 has reached a predetermined amount based on the number of image formation is effective for a page printer or the like that prints almost only characters, but is a device that can obtain a large number of solid images. In some cases, there is a large variation and good control cannot be performed.

The example shown in FIG. 8 can reduce such a problem. The screw pump 30 is intermittently operated via the MPU 14 by a pixel number detection signal for counting the number of pixels for writing a latent image on the photosensitive member 1. . Also in this example, first, the pixel count number is set to MPU1 by the pixel number detection means of the image forming apparatus.
4 to determine whether the number of pixels has reached a predetermined number (step 1). Then, when the number of pixels reaches a predetermined number, the rotor 32 of the screw pump 30 and the air pump 40 are turned on (step 2). Two seconds later, the rotor 32 is turned off (step 3), and after another five seconds from the stop of the drive, the air pump 40 is turned off (step 4), and the operation of transporting the collected toner ends.

In the image forming apparatus configured as described above, the toner transfer device 20 is controlled based on the number of pixels, so that a more reliable amount of collected toner can be known, and more stable control can be obtained.

Although the preferred embodiment of the present invention has been described above, the present invention should not be limited to the above embodiment. For example, in the above-described embodiment, the collected toner is returned to the developing unit. It can also be configured to send to means.

In the above embodiment, the apparatus for transferring the toner collected by the photosensitive member cleaning means and the transfer cleaning means together has been described.
The present invention may be configured such that only one of the photoconductor cleaning unit and the transfer cleaning unit transfers the collected toner. In particular, since the collected toner of the transfer cleaning unit contains foreign matter such as paper dust, the collected toner may be returned to the waste toner tank without being recycled.

[0053]

According to the first to third aspects of the present invention, the operation time is shortened as compared with the continuous operation, and the temperature rise due to the rotational friction between the rotor and the stator of the screw pump can be reduced, thereby blocking and deteriorating the collected toner. Can be prevented. Furthermore, since the operation time of the screw pump can be greatly reduced as compared with the continuous operation, the life of the screw pump can be dramatically increased.

According to the fourth and twelfth aspects, even if there is toner remaining in the toner transport tube when the screw pump is stopped, the toner is reliably transported toward the developing means by air. Therefore, since the amount of toner remaining in the toner transport tube is reduced, the risk of toner clogging in the tube is avoided.

According to the fifth aspect of the invention, by collecting the collected toner upstream of the screw pump, the intake port of the screw pump can be closed and air leakage can be prevented. Performance can be maintained.

According to the configuration of the sixth aspect, even if an abnormality occurs in the toner transfer by the screw pump or the like, the abnormality can be easily known without providing any special detecting means. According to the configuration of claim 7, it is possible to notify the user of the toner transfer abnormality of the screw pump or the like.

According to the eighth and eleventh aspects of the present invention, the operation time is reduced as compared with the continuous operation without using a means for detecting the amount of collected toner, and the temperature due to the rotational friction between the rotor and the stator of the screw pump is reduced. The rise can be reduced and blocking and deterioration of the collected toner can be prevented.
Furthermore, since the operation time of the screw pump can be greatly reduced as compared with the continuous operation, the life of the screw pump can be dramatically increased.

According to the ninth aspect, the operation of the screw pump and the air pump can be controlled by counting the number of image formation sheets. According to the configuration of claim 10, more accurate and stable operation control of the screw pump and the air pump than in claim 9 can be obtained.

According to the arrangements of claims 13 and 14, since the collected toner is recycled, the toner can be used without waste and the running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram illustrating an example of an image forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view illustrating an example of the toner transfer device of the present invention.

FIG. 3 is a cross-sectional view illustrating an image forming unit of the present invention.

FIG. 4 is a perspective view showing an example of the toner transfer device of the present invention.

FIG. 5 is a timing chart illustrating the operation of each unit of the image forming apparatus according to the present invention.

FIG. 6 is a cross-sectional view illustrating an example of a toner supply unit according to the present invention.

FIG. 7 is a cross-sectional view illustrating another toner transfer device of the present invention.

FIG. 8 is a flowchart showing another embodiment of the present invention.

FIG. 9 is a flowchart showing still another embodiment of the present invention.

FIG. 10 is a sectional view showing still another toner transfer device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photoconductor 4 Developing means 6, 11 Cleaning means 14 MPU 15 Toner amount detecting means 20 Toner transfer device 21 Toner reservoir 30 Screw pump 31 Stator 32 Rotor

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ichiro Komuro 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Takashi Hojima 1-3-6 Nakamagome, Ota-ku, Tokyo Share Inside Ricoh Company (72) Inventor Nobuo Kasahara 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Company (72) Inventor Satoshi Muramatsu 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Company

Claims (14)

[Claims] 1. An image forming apparatus for transferring toner removed / recovered by a cleaning unit to a toner destination as a mixture with a gas flow by operating a toner transfer unit having a screw pump and an air supply unit. An image forming apparatus, wherein a toner reservoir for storing the collected toner is provided on the upstream side in the toner transport direction of the transporter, and the toner transporter is operated when the amount of toner collected in the toner reservoir reaches a predetermined amount. . 2. The image forming apparatus according to claim 1, wherein a toner amount detecting unit is provided in the toner reservoir, and the toner transfer unit determines that the amount of the collected toner of the toner amount detecting unit has reached a predetermined amount. An image forming apparatus which is activated by a detected signal. 3. The image forming apparatus according to claim 1, wherein the operation of the toner transfer unit is continuously performed for a predetermined time and then stopped. 4. The image forming apparatus according to claim 1, wherein the operation of the screw pump is stopped when the predetermined time has elapsed after the start of the operation of the toner transfer unit, and the operation of the screw pump is delayed. Wherein the operation of the air supply means is stopped. 5. The image forming apparatus according to claim 2, wherein the toner amount detecting means is disposed near a toner intake of the screw pump, and the toner intake is set to a level at which the toner intake is substantially filled with the collected toner. An image forming apparatus characterized in that detection is performed as a fixed amount. 6. The image forming apparatus according to claim 1, wherein the toner transfer unit stops a transfer operation of the collected toner and detects a toner amount based on a detection signal of the toner amount detection unit. An image forming apparatus, comprising: a control unit for determining occurrence of abnormal transfer of collected toner. 7. The image forming apparatus according to claim 6, wherein the control unit includes a warning unit that issues a warning when the control unit determines that the collected toner is abnormally transferred. 8. An image forming apparatus for transferring toner removed / recovered by a cleaning unit to a toner destination as a mixture with a gas flow by operating a toner transfer unit having a screw pump and an air supply unit. An image forming apparatus comprising: a toner reservoir provided upstream of a transport unit in a toner transport direction; and operating the toner transport unit when it is determined that the toner in the toner reservoir has reached a predetermined amount. 9. The image forming apparatus according to claim 8, wherein the number of formed images is counted, and when the counted number reaches a predetermined number, it is considered that the collected toner in the toner reservoir has reached a predetermined amount. An image forming apparatus, wherein the toner transfer unit is operated. 10. The image forming apparatus according to claim 8, further comprising: a pixel number detecting unit that detects the number of pixels at the time of forming an image.
When the number of pixels counted by the number-of-pixels detecting means reaches a predetermined number, it is considered that the amount of the collected toner in the toner reservoir has reached a predetermined amount, and the toner transfer means is operated. 11. The image forming apparatus according to claim 8, wherein the operation of the toner transfer unit is stopped after being continuously performed for a predetermined time. apparatus. 12. The image forming apparatus according to claim 8, wherein the operation of the screw pump is stopped when the predetermined time period is reached after the operation of the toner transfer unit is started, and thereafter the toner transfer unit is delayed. Wherein the operation of the air supply means is stopped. 13. The image forming apparatus according to claim 1, wherein a toner destination to which the collected toner is transferred by operation of the toner transfer unit is a developing unit. Forming equipment. 14. The image forming apparatus according to claim 1, wherein the toner destination to which the collected toner is transferred by the operation of the toner transfer unit is a toner for transferring to a developing unit. An image forming apparatus, which is an agent storage unit that stores a developer.