JP5234400B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.

  Conventionally, in the above image forming apparatus, toner that has not been developed is scattered from the developing opening of the developing apparatus and contaminates the inside of the image forming apparatus main body, thereby degrading the image quality or adhering to the operator during maintenance. There was a problem. In order to solve this problem, Patent Document 1 discloses that an intake unit that sucks air in the developing device, a storage unit that receives air discharged from the intake unit, and a toner that is captured from the air that is supplied to the storage unit. A toner scattering prevention device including an air filter capable of collecting and retaining in a storage unit and allowing air to pass therethrough is described. In this toner scattering prevention device, the suction means sucks air in the developing device, thereby generating a suction air flow in the developing opening of the developing device and sucking in the surrounding air, thereby preventing toner scattering from the developing device. be able to. On the other hand, the air intake means sucks air in the developing device and sucks floating toner floating in the developing device. Therefore, toner is collected from the air discharged from the air sucking means by an air filter and stored in the storage unit. doing.

  Further, Patent Document 1 describes an image forming apparatus provided with a toner recycling unit that returns toner stored in a storage unit to a developing device and reuses it. By providing such toner recycling means, the collected toner can be recycled and the maintenance cost can be reduced. Further, as compared with a case where no toner recycling means is provided, the storage portion where the collected toner is stored can be reduced in size, and there is an advantage in terms of layout.

JP 2002-229331 A

  However, in the case where the toner recycling unit is provided, there is a problem that toner clogging is likely to occur in the toner discharge path for discharging the toner from the storage unit to the developing device. This will be described in detail below.

  In this toner scattering prevention device, a suction air pump is used as the suction means, and the airflow sucked by the suction air pump is sent to a toner tank as a storage unit having an air filter. The airflow sent to the toner tank passes through the air filter and is exhausted. At this time, the toner in the airflow is collected by the filter. The collected toner is stored in a toner tank. Here, in order to obtain a sufficient effect for preventing toner scattering, it is necessary to use a suction air pump having a sufficient flow rate. The internal pressure of the toner tank rises due to the difference between the large flow rate of airflow sent to the toner tank by the operation of the suction air pump and the flow rate exhausted from the toner tank through the air filter. In particular, as the rotation of the developing roller of the developing device becomes faster, a suction air pump with a larger flow rate is required, so that the internal pressure of the toner tank greatly increases. Further, when the exhaust efficiency decreases due to toner adhesion to the filter over time, the internal pressure increases several times compared to the case of the initial stage of the filter. Furthermore, when the filter area cannot be secured large due to restrictions on the layout, or when a fine filter with a small toner particle size must be used, the internal pressure rises significantly.

  From such a toner tank, the toner is discharged to a developing unit, a toner hopper, or the like through a toner discharge path using a suction type powder pump (suction type Mono pump) or a screw as a toner discharge unit. When a suction-type powder pump is used as the toner discharge means, the toner discharge path is narrowed to increase the suction force compared to the toner transport means provided with a screw in the toner discharge path. It is in a filled state. Here, if the toner filled in the toner discharge path is subjected to the increased internal pressure of the toner tank, toner aggregation may occur. In particular, when the suction type powder pump is stopped and the toner in the toner discharge path is filled without moving, if the increased internal pressure of the toner tank is applied, toner aggregation occurs in the toner discharge path and the toner is discharged. There is a risk of toner clogging in the path. When toner clogging occurs in the toner discharge path, even if the powder pump is operated next, the toner discharge performance is lowered, and continuous toner recycling cannot be performed.

  Further, even when the screw is used as the toner discharging means, the suction type powder pump is used when the toner discharge amount is large and the toner is completely filled with respect to the inner diameter of the toner discharge path. There is a possibility that toner clogging similar to the case may occur.

The present invention has been made in view of the above background, and an object of the present invention is to suck air from a developing device and send it to a storage unit, where toner is separated from the air in the storage unit, and the separated toner is converted into toner. An object of the present invention is to provide an image forming apparatus that can suppress a decrease in toner discharge performance due to an internal pressure of a storage section in an image forming apparatus that discharges from a storage section into a developing device through a discharge path.

To achieve the above object, a first aspect of the invention, a developing device that houses the current image agent, an intake means for feeding the reservoir and sucking the air in the developing device, sent into the accumulating portion and separating exhaust means for discharging air after the toner separation with stop separates the toner from the air in the accumulating portion, developing through the toner discharge path the toner fastened to the accumulating portion by the separating exhaust means from the accumulating unit in the image forming apparatus having a toner discharging means for discharging into the apparatus, opening and closing means for switching whether to set cut-off state to the communicating state both between the container portion and the toner discharge path, said switching means And a toner discharge control means for controlling the operation of the toner discharge means. The toner discharge control means is configured to open and close the storage portion and the toner discharge by the opening / closing means only when the intake means is stopped. A road to a communicating state, and is characterized in that the control to actuate said toner discharging means.
Further, the invention of claim 2, the image forming apparatus according to claim 1, said toner discharging control means, the stop after a predetermined time the inlet means, cut off and the container portion and the toner discharge path by said switching means It is characterized by controlling to be in a state.
According to a third aspect of the present invention, in the image forming apparatus according to the second aspect , the toner discharge control means is connected to the storage portion by the opening / closing means after the intake means is stopped based on the usage time of the separation exhaust means. Control is performed so as to change the time for blocking the toner discharge path.
According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, pressure detection means for detecting the pressure of the storage portion is provided, and the toner discharge control means has a pressure detection value by the pressure detection means that is a predetermined value. During the period described above, the opening / closing means controls the storage unit and the toner discharge path to be in a cut-off state.
According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect , when the time until the pressure detection value by the pressure detection means reaches a predetermined value after the stop of the intake means is a predetermined time or more, The operation of the forming apparatus main body is stopped.
According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth aspect , when the pressure detection value by the pressure detection means after a lapse of a predetermined time after the stop of the intake means is a predetermined value or more, The operation of is stopped .
Also, the invention of claim 7 is the image forming apparatus according to claim 2, 3, 4, 5 or 6, characterized in that the said toner discharging means is a suction type powder pump.

In the invention of 請 Motomeko 1 to 7, the toner discharge control unit only when the inlet means has stopped, the reservoir and the toner discharge path and the communicating state by the opening and closing means, performs toner discharge by operating the toner discharging means . Therefore, when the intake means is in operation, there is no possibility that the increased internal pressure of the storage portion is applied to the toner discharge path. Therefore, toner clogging in the toner discharge path is unlikely to occur, and a decrease in discharge performance by the toner discharge unit can be suppressed .

According to the present invention, in the image forming apparatus that sucks air from the developing device and sends it to the storage unit, separates the toner from the air in the storage unit, and discharges the separated toner from the storage unit to the developing device through the toner discharge path. There is an excellent effect that a decrease in toner discharge performance due to the internal pressure of the storage portion can be suppressed.

A first embodiment in which the present invention is applied to a copying machine as an image forming apparatus will be described below. First, the configuration and operation of the copying machine according to the first embodiment will be described.
FIG. 1 is a schematic configuration diagram of the entire copying machine according to the first embodiment. In FIG. 1, reference numeral 10 denotes an image forming unit of a copying machine. FIG. 2 is an enlarged view of a main part of the image forming unit. A drum-shaped image carrier 12 is provided in the image forming unit 10. Around the image carrier 12, a charging device 13, a developing device 14, a transfer / conveyance device 15, a cleaning device 16, a static elimination device 17, and the like are arranged.

  On top of these, a laser writing device 18 is provided. The laser writing device 18 includes a light source 20 such as a laser diode, a scanning rotary polygon mirror 21, a polygon motor 22, a scanning optical system 23 such as an fθ lens, and the like.

  A fixing device 25 is disposed on the left side of the cleaning device 16 in the drawing. The fixing device 25 is provided with a fixing roller 26 incorporating a heater and a pressure roller 27 that presses against the fixing roller 26 from below.

  A document reading device 30 is provided in the upper part of the image forming unit 10. The document reading device 30 is provided with a light source 31, a plurality of mirrors 32, an imaging lens 33, an image sensor 34 such as a CCD.

  On the other hand, a duplex unit 35 is provided in the lower part of the image forming unit 10. A re-feeding path 37 is provided from the duplex unit 35 to the feeding path 36 extending downward from the image carrier 12. The duplex unit 35 is branched from the middle of the sheet discharge path 38 extending from the outlet of the fixing device 25 to form a reverse path 39.

  A contact glass 40 is installed on the upper surface of the image forming unit 10. An automatic document feeder 41 is attached to the image forming unit 10 so as to be openable and closable so as to cover the contact glass 40.

  The image forming unit 10 as described above is placed on the paper feed table 43. In the paper feed table 43, paper feed cassettes 44 are provided in multiple stages. Each paper feed cassette 44 is provided with a corresponding paper feed roller 45. The sheet feeding roller 45 puts the fed sheet into a conveyance path 46 that leads to the sheet feeding path 36. A plurality of pairs of conveyance rollers 47 are provided in the conveyance path 46.

  When copying using such a copying machine, a document is set on the automatic document feeder 41 or the automatic document feeder 41 is opened and a document is set directly on the contact glass 40. Then, a start switch (not shown) is pressed to drive the automatic document feeder 41 to feed the document conveyed on the contact glass 40 or the document set on the contact glass 40 in advance to the document reading device 30. To read pixel by pixel.

  At the same time, an appropriate paper feed roller 45 is rotated to feed out the sheet from the corresponding paper feed cassette 44 among the plurality of paper feed cassettes in the paper feed table 43, put into the transport path 46, and transported by the transport roller 47, The sheet is put in the sheet feed path 36 and is abutted against the registration roller 48 and stopped. Then, the registration roller 48 is rotated in synchronization with the rotation of the image carrier 12, and is sent below the image carrier 12.

  On the other hand, when the start switch is pressed, the image carrier 12 is simultaneously rotated clockwise in the drawing. Then, along with the rotation of the image carrier 12, the surface is first uniformly charged by the charging device 13, and then the laser writing device 18 is irradiated with the laser light L according to the reading content read by the document reading device 30 described above. Then, writing is performed to form an electrostatic latent image on the surface of the image carrier 12, and then the toner is attached by the developing device 14 to make the electrostatic latent image visible.

  Then, as described above, the visible image is transferred by the transfer / conveyance device 15 to the sheet fed below the image carrier 12. The surface of the image carrier 12 after the image transfer is cleaned by removing the residual toner with the cleaning device 16, and with the static eliminator 17, and preparing for subsequent image formation.

  On the other hand, the image-transferred sheet is conveyed by the transfer / conveyance device 15 and put into the fixing device 25, and heat and pressure are applied by the fixing roller 26 and the pressure roller 27 to fix the transferred image. Thereafter, the paper is discharged through a paper discharge path 38 onto, for example, a tray (not shown) attached to the image forming unit 10.

  When recording on the back side of the sheet using this copying machine, after recording on one side, it is put into the duplex unit 35 through the reverse path 39, reversed there, and sent again below the image carrier 12, separately. The image formed on the image carrier 12 is similarly transferred to the back surface, and then discharged onto a tray, for example.

  Next, the developing device 14 will be described in detail with reference to FIG. The developing device 14 includes a developing tank 50 and a developing hopper 60.

  In the developing tank 50, a first developing roller 51, a second developing roller 52, a paddle wheel 53, a stirring roller 54, a conveying screw 55, a separator 56, a doctor blade 57, a toner concentration sensor 58 and the like are provided in a developing case 59. In the developing case 59, a two-component developer composed of carrier and toner is stored.

  In the developing hopper 60, a gear-shaped toner replenishing member 61, a replenishment regulating plate 62, an agitator 63, and the like are provided. The developing hopper 60 contains toner.

  In the developing device 14, the two-component developer in the developing case 59 is stirred and frictionally charged by the rotation of the stirring roller 54, and is flipped up by the rotation of the paddle wheel 53, so that the inside of the first developing roller 51 and the second developing roller 52. These magnets are attracted to the first developing roller 51 and the second developing roller 52.

  The developer adsorbed on the first developing roller 51 and the second developing roller 52 is conveyed by the sleeves on the outer periphery of the first developing roller 51 and the second developing roller 52 and scraped off the excess by the doctor blade 57. The electrostatic latent image on the image carrier 12 is developed by being attached to the image carrier 12 by a developing bias.

  In the developing device 14, when the toner adheres to the image carrier 12 and is consumed, the ratio (toner concentration) decreases. Therefore, when the toner concentration in the developer becomes equal to or lower than a predetermined value with respect to the target value of the toner concentration, the agitator 63 is rotated to stir the toner and transport the toner to the toner supply member 61. The toner supply member 61 is rotated. Then, the replenishment regulating plate 62 is swung to replenish toner from the developing hopper 60 into the developing tank 50 to maintain the toner concentration in the developer.

  The toner concentration in the developer is measured by a toner concentration sensor 58 attached to the developing case 59. The target value of the toner density is set by a value obtained by measuring a measurement toner image (P pattern) created on the image carrier 12 with a photosensor.

  In general, there are often no images on both sides of the sheet. Therefore, in order to prevent the amount of toner on both sides from increasing, toner is replenished from the developing hopper 60 in a toner replenishment area excluding both sides.

  As described above, the toner attached to the image carrier 12 is electrostatically transferred to the sheet by the transfer / conveyance device 15. However, about 10% of the toner remains untransferred and remains on the image carrier 12. Residual toner that has not been transferred and remains on the image carrier 12 is scraped off from the image carrier 12 by a cleaning blade 65 and a brush roller 66 provided in the cleaning device 16.

  The toner scraped off from the image carrier 12 by the cleaning device 16 enters the recovery tank 67 of the cleaning device 16. Then, the toner is conveyed to one side of the cleaning device 16 by the recovery screw 68, discharged from a discharge port (not shown), and led to the toner recycling device.

  As shown in FIG. 1, the copying machine includes a toner scattering prevention device 70 connected to the developing device 14. The toner scattering prevention device 70 includes an intake means 72 that is connected to the developing device 14 by an intake tube 71 and sucks air in the developing device 14, and is further connected by an intake means 72 and an exhaust tube 73 to form toner as a storage unit. A tank 74 is provided.

  The intake tube 71 is formed of a flexible rubber material (for example, silicon rubber), and a suction duct 75 is attached to the tip thereof as shown in FIG. The suction duct 75 has an elongated rectangular shape, has a connection port 76 for connecting one end of the intake tube 71 at the center of the upper surface, and opens a large opening 77 on the lower surface as shown in FIG. However, a sheet member 78 such as Mylar is attached to the lower surface of the developing hopper 60 so as to correspond to the toner replenishment region b to close the center of the opening 77, and suction ports 79 are provided on both sides. Further, a seal member 80 is attached around the opening 77 except for the developing hopper 60 side.

  Then, as shown in FIG. 2, the suction duct 75 is attached to the opening 83 of the developing case 59 by inserting both ends into a guide groove 82 provided opposite to both sides of the developing case 59 in the direction of the arrow. Thereafter, the development hopper 60 is attached to the development tank 50 to prevent it from coming off. A seal member 84 is attached to the developing hopper 60 to seal the space between the suction duct 75 and the developing hopper 60. As a result, the opening 83 of the developing case 59 is completely closed.

  FIG. 5 is an explanatory diagram of a schematic configuration of the toner scattering prevention device 70 and the toner recycling unit 110. As shown in FIG. 5, a suction pump (diaphragm type air pump) having a diaphragm is used as the intake means 72 of the toner scattering prevention device 70. The other end of the intake tube 71 is attached to the intake port 91a of such a suction pump 72, one end of the exhaust tube 73 is attached to the exhaust port 91b, and the air sucked from the duct 75 (the toner floating in the developing device 14 is also sucked simultaneously. ) To the suction suction pump 72. The exhaust tube 73 is made of a flexible rubber material (for example, silicon rubber), and conveys air (toner is also discharged) discharged from the suction pump 72 to the toner tank 74.

  Next, the suction pump 72 will be described in detail. The suction pump 72 includes a pump main body 911, a diaphragm 95, a drive motor 96 for the diaphragm 95, and the like. The pump body 91 is provided with an intake port 91a connected to the intake tube 71 and opened and closed by the intake valve 92, and an exhaust port 91b connected to the exhaust tube 73 and opened and closed by the exhaust valve 93. ing. Further, a diaphragm 95 made of a rubber material is covered in the recess of the pump body 91. Further, a drive motor 96 is provided that expands and contracts the diaphragm 95 to change the internal volume of the pump body 91. Although not shown, the pump body 91 is fixed to the side plate 99 together with the drive motor 96.

  The tip of the diaphragm 95 of the suction pump 72 is connected to one crankshaft 97. One end of the crankshaft 97 is connected to the drive motor 96. Specifically, one end of the crankshaft 97 is connected to an eccentric position on the rotary plate 98 installed on the motor shaft of the drive motor 96. With such a configuration, when the motor shaft of the drive motor 96 rotates, the diaphragm 95 expands and contracts with the eccentric rotational movement of the crankshaft 97 (expansion and contraction in the direction of a double arrow in FIG. 5).

  When the diaphragm 95 swells (when the internal volume of the pump body 91 increases), the exhaust valve 93 closes the exhaust port 91b and the intake valve 92 opens the intake port 91a. Air and floating toner in the device 14 are sucked into the pump main body 91 through the exhaust passage in the intake tube 71. On the other hand, when the diaphragm 95 is contracted (when the internal volume of the pump body 91 is reduced), the exhaust valve 93 opens the exhaust port 91b and the intake valve 92 closes the intake port 91a. Thus, the air sucked into the pump main body 91 and the floating toner are discharged toward the toner tank 74 through the exhaust passage of the exhaust tube 73. Such suction / discharge operation is repeated with the eccentric rotational movement of the crankshaft 97.

  In this manner, when the developing device 14 is operating, the suction pump 72 is operated and the air inside the developing device 14 is sucked in by the toner scattering preventing device 70, whereby the developing opening of the developing case 59 shown in FIG. By generating a suction air flow and sucking in ambient air, toner scattering from the developing device 14 can be prevented.

  In FIG. 5, the description is given using the one in which one pump main body 91 is installed as the intake means 72, but a plurality of pump main bodies are installed and the pump main body is not increased in size and the like. You may use what improved the whole pump capability. In this case, it is possible to prevent loud operating noise and damage to the valve of the pump body, which occurs when the pump body is enlarged.

  In FIG. 5, the exhaust path is formed using the intake tube 71 and the exhaust tube 73, but naturally the exhaust path may be formed using not only the tube but also a pipe or the like.

  Further, as shown in FIG. 5, the toner tank 74 has an inlet 107 for connecting the other end of the exhaust tube 73 on one upper side thereof, and an opening to which a filter 100 as a separation exhaust means is attached on the upper surface thereof. The filter 100 as the separation exhaust means is made by stretching PTFE (polytetrafluoroethylene), which is the most scientifically stable among fluororesins, with a special technique to give a fine continuous porous structure. The toner is collected, separated from the air, and stored in the toner tank 74.

  In this way, by using expanded porous PTFE as a separation and exhaust means, even when air is applied while pressure is applied, unlike other filters such as an electrostatic filter, toner leakage does not occur and toner can be reliably collected. it can.

  The air sent from the suction pump 72 through the exhaust tube 73 is put into the toner tank 74, and the toner is collected by the filter 100 and stored in the toner tank 74. The air after the toner collection passes through the filter 100 to the outside. To discharge.

  Further, toner recycling means 110 is provided for returning the toner stored in the toner tank 74 to the developing device 14 through the toner discharge path for reuse. In FIG. 5, a toner discharge hole 103 is provided at the center of the lowermost portion of the toner tank 74 for storing the collected toner. Further, the toner tank 74 is formed in a shape that tapers toward the toner discharge hole 103 so that the toner hardly remains. A nozzle 101 is connected to the toner discharge hole 103 and communicates with a toner transfer tube 159 as a toner discharge path connected to the other end of the nozzle 101.

  Further, the developing device 14 to which the toner is returned is provided with a sub hopper 161 as a sub toner storing means at the top thereof, and the toner in the toner tank 74 is temporarily stored in the sub hopper 161. On the sub hopper 161, a suction type powder pump (suction type mono pump) 170 is provided as a screw pump for transferring the toner in the toner tank 74 to the sub hopper 161. This powder pump 170 is a uniaxial eccentric screw pump, which is made of a screw rotator 171 eccentric with a material having rigidity such as metal, and an elastic body such as rubber, and is a two-thread screw shape. And a folder 173 made of a resin material or the like that encloses these and forms a powder supply path. In the rotor 171, a driving device 176 that drives a gear 175 integrally connected to a driving shaft 174 connected by a pin joint is drivingly connected to a clutch (not shown). The operation of the powder pump 170 is controlled by turning the clutch on and off under the control of the MPU 105.

  A toner suction part 177 is provided at the tip of the folder 173, that is, the right end of the powder pump 170, and the toner transfer tube 159 is connected to the toner suction part 177. As this toner transfer tube 159, for example, a flexible tube having a diameter of 4 to 10 mm and made of a rubber material having excellent toner resistance (for example, polyurethane, nitrile, EPDM, silicon, etc.) is extremely used. An effective and flexible tube can be easily piped up and down, left and right.

  The sub popper 161 is divided into an upper part and a lower part, and an upper chamber 162 and a lower chamber 163 are provided, and these communicate with each other through a communication port (not shown). The toner transferred by the powder pump 170 is supplied to the upper chamber 162 as indicated by an arrow A, and is moved in the axial direction while being agitated by the rotation of the upper screw 164 provided in the upper chamber 162. Falls to the lower chamber 163 from (not shown). In the lower chamber 163, a lower screw 165 is provided, and the toner supplied from the upper chamber moves in the axial direction while being stirred by the rotation of the lower screw 165, and enters the developing device 14 as indicated by an arrow B. Dropped and replenished. The sub hopper 161 configured as described above temporarily stores the toner supplied by the powder pump 170, and after being stirred by the screws 164 and 165, is transferred to the developing device 14.

  In the toner recycling means 110 configured as described above, the powder pump 170 is operated to generate a negative pressure in the powder pump 170, and the toner in the toner tank 74 is replenished into the sub hopper 161 through the toner transfer tube 159. .

  Here, in the toner scattering prevention device 70, it is necessary to use a suction pump 72 having a sufficient flow rate in order to obtain a sufficient effect for preventing toner scattering. For example, in the developing device 14 of FIG. 2, when the linear velocity of the developing rollers 51 and 52 is about 1000 mm / sec, a suction pump 72 having a flow rate of 6 l / min or more is used in order to obtain a sufficient effect on toner scattering. Need to use. The internal pressure of the toner tank 74 increases due to the difference between the large flow rate sent to the toner tank 74 and the flow rate exhausted from the toner tank 74 through the filter 100. In particular, when the exhaust efficiency decreases due to the toner adhering to the filter 100 over time, the internal pressure increases several times compared to the case of the initial filter. Furthermore, when the filter area cannot be secured large due to restrictions on the layout, or when a fine filter with a small toner particle size must be used, the internal pressure rises significantly.

  When toner is transferred from the toner tank 74 through the toner transfer tube 159 using the powder pump 170 as described above, the internal pressure of the toner tank 74 is applied to the toner in the toner transfer tube 159. When the internal pressure is applied, toner aggregation may occur in the toner transfer tube 159, and toner clogging may occur in the toner transfer tube 159. If toner clogging occurs in the toner transfer tube 159, the toner discharge performance is lowered and continuous toner recycling cannot be performed. In particular, when the powder pump 170 is stopped and the toner in the toner transfer tube 159 is filled without moving, if the increased internal pressure of the toner tank 73 is applied, toner aggregation in the toner tube 159 becomes remarkable. The toner tube 159 may be clogged with toner. If toner clogging occurs in the toner tube 159, even if the powder pump 170 is operated next, the toner discharge performance is lowered and continuous toner recycling cannot be performed.

  Therefore, in the toner recycling means 110 of the first embodiment, the toner tank 74 and the toner transfer tube 159 can be switched to the communication state or the blocking state for the nozzle 101 connecting the toner tank 74 and the toner transfer tube 159. An electromagnetic valve 102 is provided as a possible opening / closing means. Then, the operation and non-operation of the electromagnetic valve 102 and the powder pump 170 are controlled by the MPU 105 which is a copying machine main body control unit having toner discharge control means (not shown). The MPU 105 controls the powder pump 70 to operate when the toner valve 74 and the toner transfer tube 159 are in communication with each other by opening the electromagnetic valve 102, and sucks the toner through the toner transfer tube 159. The toner is discharged from the unit. Here, the powder pump 170 is controlled to operate in synchronization with the electromagnetic valve 102 and operates only when the electromagnetic valve 102 is opened. In other cases, the MPU 105 controls the electromagnetic valve 102 to close, shuts off the toner tank 74 and the toner transfer tube 159, and the internal pressure of the toner tank 74 is applied to the toner in the toner transfer tube 159. Avoid it. As described above, when the powder pump 170 is not operated and the toner is not moving in the toner transfer tube 159, the internal pressure of the toner tank 74 is prevented from being applied to the toner in the toner transfer tube 159. As a result, toner clogging in the toner transfer tube 159 is less likely to occur, and the toner discharge performance can be maintained.

  Next, the timing for controlling the MPU 105 to open the electromagnetic valve 102 and perform the toner discharging operation in order to suppress the influence of the toner tank internal pressure on the toner discharging performance more efficiently will be described. FIG. 9A is a graph showing changes in the internal pressure of the toner tank when the suction pump 72 is operated. 9B and 9C are operation timing charts of the suction pump 72, the electromagnetic valve 102, and the powder pump 170 controlled by the MPU 105. FIG.

  As shown in FIG. 9A, the internal pressure of the toner tank 74 is increased by the operation of the suction pump 72. However, since the air in the toner tank 74 is gradually discharged through the filter 100, the pressure increases when the suction pump 72 is stopped. The internal pressure is reduced and gradually returns to the original state before the suction pump 72 is operated.

  As shown in FIGS. 9B and 9C, the MPU 105 controls to open the electromagnetic valve 102 and operate the powder pump 170 when the suction pump 72 is stopped. Otherwise, the electromagnetic valve 102 is closed and the powder pump 170 is controlled to stop. As a result, when the internal pressure rises while the suction pump 72 is operating, the toner tank 74 and the toner transfer tube 159 are disconnected from each other so that the increased internal pressure is not applied to the toner in the toner transfer tube 159. By controlling the operation of the suction pump 72, the electromagnetic valve 102, and the powder pump 170 at such timing, it is possible to efficiently eliminate the influence due to the increase in the internal pressure of the toner tank.

  Further, particularly in FIG. 9 (c), the MPU 105 closes the electromagnetic valve 102 during the operation of the suction pump 72 and for a predetermined time after the stop, shuts off the toner tank 74 and the toner transfer tube 159, and removes the powder. The pump 170 is controlled to stop. Then, after a predetermined time has elapsed, at a timing when the internal pressure of the toner tank 74 decreases and approaches the original state, control is performed so that the electromagnetic valve 102 is opened and the powder pump 170 is operated.

  The magnitude of the change in the internal pressure of the toner tank 74 is determined by the difference between the flow rate of air sent to the toner tank 74 and the flow rate exhausted from the toner tank 74 through the filter 100. It is greatly affected. Specifically, as shown in FIG. 9 (a), at the initial stage after replacement of the filter 100, the discharge efficiency of the filter 100 is good, so the increase in internal pressure is small, and the increased internal pressure returns to the original state in a relatively short time. On the other hand, since the toner clogging occurs in the filter 100 with the passage of time after the replacement of the filter 100, the increase in the internal pressure increases, and the increased internal pressure requires a long time to return to the original state.

  Therefore, in particular, in FIG. 9B, control is performed so that the electromagnetic valve 102 is opened and the powder pump 170 is operated at different times after the suction pump 72 is stopped after the filter 100 has been replaced and when it has elapsed. . Specifically, the MPU 105 calculates the usage time of the filter and the like, taking into account the time until the increased internal pressure returns to the original state. After the suction pump 72 is stopped, the electromagnetic valve 102 is opened and the powder pump 170 is operated. Decide the time to start. In the initial stage after the replacement of the filter 100, when it is determined that the internal pressure reduction rate after the suction pump 72 is stopped is high, the solenoid valve 102 is opened in a short time after the suction pump is stopped, and the operation of the powder pump 170 is started. ing.

  In FIG. 9B, the powder pump 170 is controlled to operate in synchronization with the electromagnetic valve 102 and operates only when the electromagnetic valve 102 is opened. However, when the MPU 105 opens the electromagnetic valve 102 and operates the powder pump 170 only when the suction pump 72 is stopped, the powder pump 170 does not necessarily operate in synchronization with the electromagnetic valve 102. It is not necessary to control to do. As shown in FIG. 10, the electromagnetic valve 102 may be controlled to remain open after the powder pump 170 is stopped and to shut off the electromagnetic valve 102 when the next suction pump 10 is operated. In this case, there is no possibility that the increased toner tank internal pressure when the suction pump 72 is operated will be applied to the toner transfer tube 159. Therefore, the toner clogging in the toner transfer tube 159 is less likely to occur, and a decrease in discharge performance by the powder pump 170 can be suppressed.

  FIG. 6 is an explanatory diagram of a device provided with a pressure sensor 104 for detecting the internal pressure of the toner tank 74. In FIG. 6, in order to more surely eliminate the influence on the toner discharge performance due to the increase in the internal pressure of the toner tank 74, the pressure sensor 104 detects the internal pressure of the toner tank, and the detected internal pressure is below a predetermined value. After confirmation, the electromagnetic valve 102 is opened, and the MPU 105 controls to start the operation of the powder pump 170. In the control based on the detected internal pressure, the operation of the powder pump 170 is initially performed after the filter replacement, as compared with the control based on the predetermined time after the suction pump 72 is stopped as shown in FIGS. 9B and 9C. There is a merit of starting early. It is also possible to control to extend the filter replacement cycle over time.

  However, if it takes too much time for the internal pressure to become a predetermined value or less, a problem that affects the timing of the next image formation start occurs. For this reason, when the time until the pressure reaches the predetermined pressure after stopping the suction pump 72 becomes a predetermined value or more, a filter replacement message is issued and the machine is stopped immediately, or the machine is stopped after the predetermined operation time. desirable. The control based on the detected internal pressure is such that the electromagnetic valve 102 is opened and the operation of the powder pump 170 is started depending on whether or not the pressure detection value at a predetermined time after the suction pump 72 is stopped is equal to or less than a predetermined value. But you can.

  FIG. 7 is an explanatory diagram of a toner discharge unit using a screw 150 instead of the powder pump 107 shown in FIG. In FIG. 6, a toner transfer path 151 as a toner discharge path is connected to the other end of the nozzle 101 connected to the toner discharge hole 103 at the bottom of the toner tank 74. In the toner transfer path 151, a screw 150 as a toner discharging means is disposed, and a driving device 152 for driving the screw 150 is drivingly connected to a clutch (not shown). The operation of the screw 150 is controlled by turning the clutch on and off under the control of the MPU 105.

  The toner transfer path 151 is in communication with the developing device 14, and the toner transferred through the toner transfer path 151 by the screw 150 is supplied to the developing device 14 through an opening 153 that is in communication with the developing device 14. . A sub hopper (not shown) may be provided between the toner transfer path 151 and the developing device 14.

  As described above, even when the screw 150 is used as the toner discharging means, if the toner discharge amount is large and the toner is completely filled with respect to the inner diameter of the toner transfer path 151, the powder shown in FIGS. There is a possibility that toner clogging similar to the case of using the pump 170 may occur. Further, when the toner conveyance amount is small and there is a space in the toner transfer path 151, the internal pressure of the toner tank increases the internal pressure of the developing device 14 and the sub hopper as the transfer destination.

  Therefore, as in FIGS. 5 and 6, as an opening / closing means capable of switching the toner tank 74 and the toner transfer path 151 to the communication state or the blocking state to the nozzle 101 connecting the toner tank 74 and the toner transfer path 151. The electromagnetic valve 102 is provided. The operations of the electromagnetic valve 102 and the screw 150 are controlled by an MPU 105 which is a copying machine main body control unit having toner discharge control means (not shown).

  The MPU 105 controls the screw 150 to operate when the electromagnetic valve 102 is opened and the toner tank 74 and the toner transfer path 151 are in communication with each other, and the toner is discharged from the toner tank 74 through the toner transfer path 151. . In other cases, the MPU 105 controls the electromagnetic valve 102 to be closed to shut off the toner tank 74 and the toner transfer path 151 so that the internal pressure of the toner tank 74 is not applied to the toner transfer path 151. To. Thus, the electromagnetic valve 102 is provided to prevent the internal pressure of the toner tank 74 from being applied to the toner transfer path 151. As a result, even when the amount of toner transfer is large, toner clogging in the toner transfer path 151 does not easily occur, and a decrease in toner discharge performance can be suppressed. Further, even when the toner conveyance amount is small, it is possible to prevent an increase in internal pressure of the developing device 14 and the sub hopper.

  Further, as described above, the MPU 105 controls the electromagnetic valve 102 to open and the screw 150 to operate when the suction pump 72 is stopped. In other cases, control is performed so that the electromagnetic valve 102 is closed and the screw 150 is stopped. Thus, when the internal pressure rises while the suction pump 72 is in operation, the toner tank 74 and the toner transfer path 151 are disconnected from each other so that the increased internal pressure is not applied to the toner transfer path 151. By controlling the operation of the suction pump 72, the electromagnetic valve 102, and the screw 150 at such timing, it is possible to efficiently eliminate the influence of the increase in the internal pressure of the toner tank.

  Further, the MPU 105 controls the electromagnetic valve 102 to be closed, the toner tank 74 and the toner transfer path 151 are shut off, and the screw 150 is stopped while the suction pump 72 is in operation and for a predetermined time after the stop. Then, after the predetermined time has passed, the electromagnetic valve 102 may be opened and the screw 150 may be operated at the timing when the internal pressure of the toner tank 74 decreases and approaches the original state. Further, it may be controlled to open the electromagnetic valve 102 and operate the screw 150 at different times after the suction pump 72 is stopped at the initial stage after replacement of the filter 100 and over time.

  Further, as shown in FIG. 6, a pressure sensor 103 for detecting the internal pressure of the toner tank 74 may be provided, and control based on the detected internal pressure may be performed.

  Next, a second embodiment in which the present invention is applied to a copying machine as an image forming apparatus will be described. The entire operation of the copying machine and the toner scattering prevention device according to the second embodiment are the same as the overall operation of the copying machine and the toner scattering prevention device according to the first embodiment. Omitted. Here, an apparatus for suppressing a decrease in toner discharge performance due to the internal pressure of the toner tank 74 of the toner recycling means, which is a characteristic part of the copying machine according to the second embodiment, will be described.

  FIG. 8 is an explanatory diagram of a schematic configuration of the toner scattering prevention device 70 and toner recycling means employed in the copying machine according to the second embodiment. In FIG. 8, a toner amount sensor 105 for detecting the toner amount in the toner tank 74 is provided. The operation of the powder pump 170 is controlled by a toner discharge control means (not shown) of the MPU 105 which is a copying machine main body control unit. Unlike the first embodiment, an electromagnetic valve that switches the toner tank 74 and the toner transfer tube 159 to the communication state or the cutoff state is not provided. In FIG. 8, the toner amount in the toner tank 74 is detected by the toner amount sensor 106, and the operation of the powder pump 170 as the toner discharging means is controlled so that the toner amount does not become a predetermined amount or less. That is, the MPU 105 operates the powder pump 170 only when the toner amount sensor 106 determines that the toner amount in the toner tank 74 is greater than a certain level. Thus, a certain amount of toner is stored so as to cover the upper part of the discharge hole 103 communicating with the toner transfer tube 159 below the toner tank 74. The fixed amount of toner stored in the lower portion of the toner tank 74 functions as a buffering means for buffering so that the internal pressure of the toner tank 74 is not directly applied to the thin toner transfer tube 159. As described above, since the internal pressure of the toner tank 74 is less likely to be directly applied to the toner transfer tube 159, toner clogging in the toner transfer tube 159 is less likely to occur, and a decrease in toner discharge performance can be suppressed.

  FIG. 11 is an operation timing chart of the suction pump 72 and the powder pump 170 controlled by the MPU 105 based on the detection value of the toner amount sensor 106. In FIG. 8, when the toner amount sensor 106 detects that the toner amount in the toner tank 74 is less than a certain amount, the toner transfer by the powder pump 170 is stopped. When the toner amount sensor 106 detects that the toner amount in the toner tank 74 is larger than a certain amount, the powder pump 170 is operated to transfer the toner. In the example of FIG. 11, in order to reduce the number of times the powder pump 170 is turned ON / OFF to ensure durability, the toner amount sensor 105 detects the powder after a predetermined time when the toner amount is detected to be greater than a certain amount. The body pump 170 is operating. In this case, the toner recovery amount per unit time is set smaller than the powder pump conveyance capacity.

  In the first and second embodiments, the present invention has been described using the filter 100 as the separation exhaust means. However, even when a cyclone having a toner separation function is used as the separation exhaust means instead of the filter 100, there is a possibility that a problem due to an increase in toner tank internal pressure may occur. In the case of using a cyclone as the separation exhaust means, there are a positive pressure type cyclone that connects the suction air pump to the cyclone inlet side and a negative pressure type cyclone that connects the suction air pump to the cyclone outlet side. In the case of a positive pressure type cyclone, there is a possibility that toner clogging may occur in the toner discharge path as in the above-described filter. On the other hand, in the case of a negative pressure type cyclone, the negative pressure on the toner tank side becomes larger than the negative pressure generated by the powder pump, and there is a possibility that the toner cannot be transferred. As described above, the present invention can also be applied to the case where a cyclone is used as the separation exhaust means, and the same effect can be obtained.

As described above, according to the first embodiment, the suction pump 10 as the suction unit that sucks the air in the developing device 14 and sends it to the toner tank 74 as the storage unit, and the toner from the air sent to the toner tank 74. A filter 100 serving as a separation exhaust unit for separating and retaining in the toner tank 74 and exhausting the air from which the toner has been separated, and a toner for discharging the toner retained in the toner tank 74 through a toner transfer tube 159 serving as a toner discharge path. A powder pump 170 is provided as a discharging means. An electromagnetic valve 102 as an opening / closing means for switching the toner tank 74 and the toner transfer tube 159 to a communication state or a blocking state, and an MPU 105 having a toner discharge control means for controlling the operation of the electromagnetic valve 102 and the powder pump 170 Is provided. The MPU 105 switches between communication and blocking of the toner tank 74 and the toner transfer tube 159 by the electromagnetic valve 102 according to the operation and non-operation of the powder pump 170. Specifically, when the powder pump 170 is operated, the toner tank 74 and the toner transfer tube 159 are brought into communication with each other by the electromagnetic valve 102 and the toner is discharged through the toner transfer tube 159. When the powder pump 170 is not operated, the toner tank 74 and the toner transfer tube 159 are shut off by the electromagnetic valve 102 so that the internal pressure of the toner tank 74 is not applied to the toner transfer tube 159. That is, when the powder pump 170 is not operated and the toner is not moving in the toner transfer tube 159, there is no possibility that the internal pressure of the toner tank 74 is applied to the toner in the toner transfer tube 159. Therefore, toner clogging in the toner transfer tube 159 is unlikely to occur, and a decrease in discharge performance by the powder pump 170 can be suppressed.
Further, the MPU 105 controls the electromagnetic valve 102 to be opened and the powder pump 170 to be operated when the suction pump 72 is stopped. In other cases, the electromagnetic valve 102 is closed and the powder pump 170 is controlled to stop. As a result, when the internal pressure increases while the suction pump 72 is operating, the toner tank 74 and the toner transfer tube 159 are shut off so that the increased internal pressure is not applied to the toner in the toner transfer tube 159. By controlling the operation of the suction pump 72, the electromagnetic valve 102, and the powder pump 170 at such timing, there is no possibility that the increased internal pressure of the toner tank 74 is applied to the toner transfer tube 159 when the suction pump 72 is operated. . Therefore, toner clogging in the toner transfer tube 159 is unlikely to occur, and a decrease in discharge performance by the toner discharge unit can be suppressed.
Further, the MPU 105 opens the electromagnetic valve 102 to bring the toner tank 74 and the toner transfer tube 159 into communication so that the powder pump 170 is operated when the suction pump 72 is stopped. Further, when the suction pump 72 is operating, the powder pump 170 is also inactivated, the toner tank and the toner transfer tube 159 are shut off by the electromagnetic valve 102, and the toner transfer tube 159 is not moving. The toner tank pressure that has risen is not applied to the toner. By controlling in this way, toner clogging in the toner transfer tube 159 is less likely to occur, and a decrease in discharge performance by the powder pump 170 can be suppressed.
Further, the MPU 105 controls the electromagnetic pump 102 to be closed, the toner tank 74 and the toner transfer tube 159 are shut off while the suction pump 72 is in operation and for a predetermined time after the stop, and the powder pump 170 is stopped. . Then, after a predetermined time has elapsed, at a timing when the internal pressure of the toner tank 74 decreases and approaches the original state, control is performed so that the electromagnetic valve 102 is opened and the powder pump 170 is operated. In this way, when the internal pressure rises during the operation of the suction pump 72 and during a predetermined time after the stop, the toner tank 74 and the toner transfer tube 159 are shut off so that the increased internal pressure is not applied to the toner in the toner transfer tube 159. To do. By controlling the operations of the suction pump 72, the electromagnetic valve 102, and the powder pump 170 at such timing, it is possible to more efficiently suppress a decrease in toner discharge performance due to the internal pressure of the toner tank 74.
In addition, control is performed so that the electromagnetic valve 102 is opened and the powder pump 170 is operated at different times after the suction pump 72 is stopped at an initial stage after the replacement of the filter 100 and over time. Here, the magnitude of the change in the internal pressure of the toner tank 74 is determined by the difference between the flow rate of air sent to the toner tank 74 by the suction pump 72 and the flow rate of air exhausted from the toner tank 74 through the filter 100. The filter 100 is greatly affected by the discharge efficiency. Specifically, at the initial stage after replacement of the filter 100, the discharge efficiency of the filter 100 is good, so that the increase in internal pressure is small, and the increased internal pressure returns to the original state in a relatively short time. On the other hand, since the toner clogging occurs in the filter 100 with the passage of time after the replacement of the filter 100, the increase in the internal pressure increases, and the increased internal pressure requires a long time to return to the original state. Therefore, the MPU 105 calculates the usage time of the filter 100 and the time until the increased internal pressure returns to the original state is taken into account. After the suction pump 72 is stopped, the electromagnetic valve 102 is opened and the powder pump 170 is operated. Decide the time to start. By controlling the operations of the suction pump 72, the electromagnetic valve 102, and the powder pump 170 at such timing, it is possible to more efficiently suppress a decrease in toner discharge performance due to the internal pressure of the toner tank 74.
Further, a pressure sensor 104 that detects the internal pressure of the toner tank 74 is provided, and the internal pressure is detected by the pressure sensor 104. Then, after confirming that the detected internal pressure is equal to or lower than the predetermined value, the MPU 105 opens the electromagnetic valve 102 and controls to start the operation of the powder pump 170. In the control based on the detected internal pressure, the influence on the toner discharge performance due to the increase in the internal pressure of the toner tank 74 can be more reliably excluded as compared with the control based on the predetermined time after the suction pump 72 is stopped. In addition, there is also an advantage that the operation of the powder pump 170 can be started early at the initial stage after the filter replacement. It is also possible to control to extend the filter replacement cycle over time.
Also, in the control based on the detected internal pressure, if it takes too much time for the internal pressure to become a predetermined value or less, a problem that affects the timing of the next image formation start occurs. For this reason, when the time until the pressure reaches the predetermined pressure after stopping the suction pump 72 becomes a predetermined value or more, a filter replacement message is issued and the machine is stopped immediately, or the machine is stopped after the predetermined operation time. Further, as control based on the detected internal pressure, control is performed to open the electromagnetic valve 102 and start the operation of the powder pump 170 depending on whether or not the pressure detection value at a predetermined time after the suction pump 72 is stopped is equal to or less than a predetermined value. But you can.
The same effect can be obtained by using a screw 150 instead of the powder pump 170 as the toner discharging means. When the screw 150 is used as the toner discharging means, if the toner discharge amount is large and there is a portion where the toner is completely filled with respect to the inner diameter of the toner transfer path 151, the same as when the powder pump 170 is used. There is a possibility of toner clogging. Further, when the toner conveyance amount is small and there is a space in the toner transfer path 151, the internal pressure of the toner tank 74 may increase the internal pressure of the developing device 14 or the sub hopper as the transfer destination. Therefore, the nozzle 101 that connects the toner tank 74 and the toner transfer path 151 is provided with an electromagnetic valve 102 that can switch the toner tank 74 and the toner transfer path 151 to a communication state or a blocking state. Further, by performing the above-described control by the MPU 105, even when the toner transfer amount is large, the toner clogging in the toner transfer path 151 is difficult to occur, and a decrease in toner discharge performance can be suppressed. Further, even when the toner conveyance amount is small, it is possible to prevent an increase in internal pressure of the developing device 14 and the sub hopper.
Further, according to the second embodiment, the suction pump 10 as the suction unit that sucks the air in the developing device 14 and sends it to the toner tank 74 as a storage unit, and the toner from the air sent to the toner tank 74. The toner is discharged through a filter 100 serving as a separation exhaust unit that collects and retains the toner in the toner tank 74 and exhausts the air that has collected the toner, and a toner transfer tube 159 serving as a toner discharge path that is retained in the toner tank 74. A powder pump 170 is provided as toner discharging means. Then, an MPU 105 having a toner amount sensor 106 for detecting the amount of toner stored in the toner tank 74 and a toner discharge control means for controlling the operation of the powder pump 170 is provided. The MPU 105 controls to stop the operation of the powder pump 170 when the toner amount detected by the toner amount sensor 106 is equal to or less than a predetermined value, and secures a certain amount of toner storage in the toner tank 74. A certain amount of toner stored in the toner tank 74 functions as a buffering means for buffering so that the internal pressure of the toner tank 74 is not directly applied to the toner transfer tube 159. As described above, since the internal pressure of the toner tank 74 is less likely to be directly applied to the toner transfer tube 159, toner clogging in the toner transfer tube 159 is less likely to occur, and a decrease in discharge performance by the powder pump 170 can be suppressed.
Further, in the case where the toner discharging means is the powder pump 170 and the conveying means is not disposed in the toner discharging path such as a screw, the toner transfer tube 159 as the toner discharging path becomes thin, so that the toner discharging performance is deteriorated. A great effect for suppression is obtained.

FIG. 3 is a schematic configuration diagram of an entire copying machine according to first and second embodiments. FIG. 2 is an enlarged view of a main part of an image forming unit of a copying machine. The perspective view of a suction duct. The perspective view which looked at the suction duct from the lower surface side. FIG. 3 is a schematic configuration explanatory diagram of a toner scattering prevention device and a toner recycling unit according to the first embodiment. FIG. 6 is a schematic configuration explanatory diagram of a modified example of a toner scattering prevention device and a toner recycling unit. FIG. 7 is a schematic configuration explanatory diagram of another modified example of the toner scattering prevention device and toner recycling means. FIG. 6 is a schematic configuration explanatory diagram of a toner scattering prevention device and toner recycling means according to a second embodiment. FIG. 4 relates to toner recycling means according to the first embodiment, wherein (a) is a graph showing changes in the internal pressure of the toner tank due to operation of the suction pump, and (b) and (c) are operation timing charts. The modification of the operation timing chart of a suction pump, an electromagnetic valve, and a powder pump. 10 is an operation timing chart regarding toner recycling means according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming part 12 Image carrier 14 Developing device 70 Toner scattering prevention device 71 Intake tube 72 Suction pump 73 Exhaust tube 74 Toner tank 75 Suction duct 79 Suction port 86 Suction pump 91 Pump body 91a Suction port 91b Exhaust port 92 Suction valve 93 Exhaust valve 95 Diaphragm 96 Drive motor 97 Crankshaft 98 Rotating plate 100 Filter 101 Nozzle 102 Electromagnetic valve 103 Discharge hole 104 Pressure sensor 105 MPU
106 Toner amount sensor 110 Toner recycling means 159 Toner transfer tube 161 Sub hopper 170 Powder pump 176 Powder pump drive device

Claims (7)

A developing device that houses the current image, toners separated with fastening and inlet means for feeding the reservoir and sucking the air in the developing device, the the accumulating portion to separate the toner from the air sent to the accumulating portion An image forming apparatus comprising: separation exhaust means for discharging the subsequent air; and toner discharge means for discharging toner retained in the storage portion by the separation exhaust means from the storage portion into the developing device through a toner discharge path. In
And switching means for switching whether to set cut-off state both to the communication state between the reservoir and the toner discharge path, and a toner discharge control means for controlling operation of said opening and closing means and said toner discharging means provided The toner discharge control means controls the operation of making the toner discharge means operate by bringing the reservoir and the toner discharge path into communication with each other only when the intake means is stopped. Image forming apparatus. 2. The image forming apparatus according to claim 1 , wherein the toner discharge control unit controls the storage unit and the toner discharge path to be cut off by the opening / closing unit for a predetermined time after the intake unit is stopped. An image forming apparatus. 3. The image forming apparatus according to claim 2 , wherein the toner discharge control unit is configured to shut off the storage unit and the toner discharge path by the opening / closing unit after the intake unit is stopped based on a usage time of the separation exhaust unit. An image forming apparatus that controls to change the time for The image forming apparatus according to claim 1, further comprising a pressure detection unit configured to detect the pressure of the storage unit, wherein the toner discharge control unit is configured to perform the opening / closing unit while the pressure detection value by the pressure detection unit is equal to or greater than a predetermined value. An image forming apparatus, wherein the storage unit and the toner discharge path are controlled to be cut off. 5. The image forming apparatus according to claim 4 , wherein the operation of the main body of the image forming apparatus is stopped when the time until the pressure detection value by the pressure detecting means reaches a predetermined value after the stop of the intake means is a predetermined time or more. An image forming apparatus. 5. The image forming apparatus according to claim 4 , wherein the operation of the main body of the image forming apparatus is stopped when a pressure detection value by the pressure detection means after a predetermined time has passed after the intake means is stopped, when the pressure detection value is a predetermined value or more. Image forming apparatus . The image forming apparatus 請 Motomeko 1,2,3,4,5 or 6, the image forming apparatus characterized by the above toner discharging means is a suction type powder pump.

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