JP3940238B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an image forming apparatus, and in particular, a printer that forms an image by supplying toner as an air-fuel mixture to an electrostatic latent image formed on an image carrier in an electrophotographic system from a position away from a development position. The present invention relates to an image forming apparatus such as a facsimile machine, a copying machine, or a complex machine of these.
[0002]
[Prior art]
  In an image forming apparatus such as an electrophotographic printer, a facsimile machine, a copying machine or a composite machine using a dry one-component or two-component developer, a toner hopper is connected to the developing device to store toner. It is known to perform a toner supply operation by a toner replenishing roller based on a detection signal of a pressure sensor that detects the pressure of toner in the area between the developing roller and the layer forming member in the section (Japanese Patent Laid-Open No. 7-253709). See the publication). In addition to replenishing new toner, the recovered toner obtained by recovering the toner remaining on the image carrier after the transfer process is returned to the developing device as an air-fuel mixture and reused to form an image. In an image forming apparatus equipped with a toner recycling mechanism, toner that has been transferred to a photosensitive member of an image bearing member but has not been transferred onto a transfer member or toner that remains on a transfer belt. After being collected by the cleaning means, recycle development is performed in which it is returned to the developing device and reused. However, the collected recovered toner contains foreign particles such as aggregated toner resulting from toner aggregation over time and paper dust adhering to the photoreceptor of the image carrier, and during the cleaning process and the recovery process. Foreign particles are formed when toners are coarsened while agglomerating and solidifying, but these foreign materials generate black spots or the like on the formed image and deteriorate the quality of the formed image. Therefore, it is not possible to pass the collected toner through a cyclone separator to eliminate paper dust and coarse particles, or to separate the toner from other particles using multiple filters with different mesh eyes. Known (see Japanese Patent Laid-Open Nos. 58-163978, 61-67074, and 7-77906). Or, since the collected toner is often deteriorated in characteristics such as chargeability and fluidity compared to the new toner, the collected toner is conveyed little by little to the developing device and stirred with a large amount of new toner. There is also a known technique in which the amount of new toner used is reduced and the cost per transfer sheet is reduced. For example, the toner recovered by the cleaning means is returned to the developing device by rotating the screw conveyor in the transport pipe, and the mixing ratio with the new toner is controlled so that the deteriorated recovered toner is used. A developing device in which defects are less likely to occur is known (see Japanese Laid-Open Patent Publication No. 6-175488).
[0003]
  Further, a toner storage unit, a toner supply unit, a toner transfer unit, and the like are arranged at arbitrary positions apart from the developing unit, respectively, and a rotor that moves the toner of the developer in the axial direction by rotating, and a path that encloses the rotor A screw pump having a rotor and a fixed stator that contacts and engages inside the passage, and an air supply means for supplying air for fluidizing the developer moved by the screw pump. A technique is also known in which an air-fuel mixture composed of toner and air is transported from a toner storage unit into a developing unit through a tube made of an elastic body of a transport unit (Japanese Patent Laid-Open No. 7-219329). See). Such a screw pump takes advantage of the downsizing and space saving of the toner conveying device and the ability to convey toner in the vertical vertical direction, improving the flexibility of the main unit and unit layout, assembling and maintenance. Not only is it used for transporting new toner due to its improved performance and low cost, but it can also be used for transporting recycled toner that can be reused by returning the recovered toner collected by the cleaning means to the developing means. It has been proposed by the inventor of the same applicant. In a conventional image forming apparatus using a screw pump of a gas flow transfer means for moving such toner as a gas mixture, the toner and gas mixture is moved in an elastic tube that conveys the gas mixture by movement or vibration. There is a possibility that the toner is clogged and the toner cannot be conveyed. At this time, when the maximum pressure of the gas supply device is lower than the pressure resistance of the screw pump of the gas flow transfer means, the toner enters the gas supply device, and the toner scatters into the device and locks the screw pump of the gas flow transfer means. Occurs and breaks. On the contrary, when the maximum pressure of the gas supply device is higher than the pressure resistance of the screw pump of the gas flow transfer means, the gas supplied to the screw pump of the gas flow transfer means puts the toner upstream of the screw pump of the gas flow transfer means. The toner flows backward, and the toner accumulates upstream of the screw pump of the gas flow transfer means. In this case, it can be detected by providing a toner remaining amount detecting means on the upstream side, but the abnormality cannot be detected until the toner is accumulated to some extent. Also, when an abnormality occurs in the gas supply device, the toner cannot be transported in the same manner, so that the toner enters the gas supply device, the toner scatters into the device, and the screw pump lock of the gas flow transfer means occurs. Each device is damaged. Accordingly, in such a conventional image forming apparatus, even if an abnormal conveyance of toner to the developing unit occurs, it is difficult to detect and slow, so that the toner scatters and the gas flow transfer unit locks and breaks. Has occurred.
[0004]
[Problems to be solved by the invention]
  Such a conventional image forming apparatus described above has a problem that it is difficult to detect even if abnormal conveyance of toner to the developing unit occurs, and the toner is scattered and broken due to the lock of the gas flow transfer unit. It was happening. Therefore, an object of the present invention is to solve such problems. That is, the running cost to prevent the occurrence of toner scattering, gas flow transfer means locking, and device damage accidents by determining the occurrence of abnormal toner conveyance to the developing means and the replacement timing of the surplus gas flow discharge means easily and early. An object of the present invention is to provide an image forming apparatus having a low image quality.
[0005]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention of claim 1 forms an image by supplying toner to the electrostatic latent image formed on the image carrier as a gas mixture with gas from a position away from the development position. In an electrophotographic image forming apparatus, an image carrier that carries a formed image, a developing unit that visualizes an electrostatic latent image formed on the image carrier and forms a toner image, and a developing unit A toner hopper for replenishing toner, an air-fuel mixture transport path for transporting a mixture of toner and gas to the toner hopper, a gas flow transfer means for transporting toner to the air-fuel mixture transport path as a gas mixture, and Gas supply means for supplying gas to the gas flow transfer means, and detecting the internal pressure in the toner hopperPressure sensorAnd comprisingFrom the pressure sensorThe main feature is that it has an abnormal conveyance discrimination control means for discriminating the occurrence of abnormal conveyance of the mixture of toner and gas by the internal pressure detection signal.
  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the gas flow transfer means is an image forming apparatus that transfers the collected toner collected by the cleaning means after image formation. .
  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the cleaning means is an image forming apparatus that collects toner remaining on the image carrier.
  According to a fourth aspect of the present invention, in the image forming apparatus according to the first, second, or third aspect,Above pressure sensorThe main feature is that the internal pressure in the toner hopper is detected from the time of operation of the gas flow transfer means and the gas supply means.
  According to a fifth aspect of the present invention, in the image forming apparatus according to the first, second, third, or fourth aspect, the internal pressure in the toner hopper is detected.Pressure sensorIs arranged above the position of the toner accumulated in the toner hopper.
  According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect,the aboveAbnormal conveyance discrimination control meansbyThe main feature is that it has a warning means for warning the determination result of abnormal conveyance.
  The main feature of the present invention of claim 7 is that the toner hopper is an image forming apparatus having surplus gas flow discharge means for discharging a surplus gas flow.
  The main feature of the present invention of claim 8 is that the surplus gas flow discharge means is an image forming apparatus which is a gas filter.
  The present invention of claim 9Abnormal conveyance discrimination control meansThe main feature is to determine the replacement time of the gas filter.
[0006]
[Action]
  In the image forming apparatus configured as described above, in claim 1, the toner is applied to the developing unit that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms a toner image. In the toner hopper to be replenished, the gas is supplied to the gas flow transfer means and the gas flow transfer means for transferring the toner as a gas mixture to the gas mixture transfer path and the gas mixture transfer path in the toner hopper to be replenished. When the toner is transported from a position away from the development position by the gas supply means, the internal pressure in the toner hopper is reduced.Pressure sensorThus, it is possible to provide an image forming apparatus that can easily detect the occurrence of abnormal conveyance of toner to the developing unit and prevent the occurrence of toner scattering, gas flow transfer unit locking, and device damage accidents. Make it possible. Further, in the toner hopper that replenishes the toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms the toner image, the toner is mixed with the gas, When the toner is transported from a position away from the developing position by the gas flow transfer means for transferring the toner to the gas mixture transfer path and the gas mixture transfer path and the gas supply means for supplying the gas to the gas flow transfer means. The internal pressure in the toner hopperPressure sensorWhen detected withbothBy detecting the abnormal conveyance of the mixture of toner and gas based on the detection signal of the internal pressure of the pressure sensor by the abnormal conveyance determination control means, it is possible to more easily determine the occurrence of abnormal conveyance of the toner conveyance to the developing means. Thus, it is possible to provide an image forming apparatus that prevents the occurrence of toner scattering, gas flow transfer means locking, and device damage accidents.
  3. The image forming apparatus according to claim 2, wherein the electrostatic latent image formed on the image carrier that carries the formed image is visualized and the toner is supplied to the developing unit that supplies toner to the toner hopper after the image is formed. Gas supply means for supplying the gas to the gas flow transfer means and the gas flow transfer means for transferring the toner collected as a gas mixture to the gas mixture transfer path and the gas mixture transfer path When the toner is transported from a position away from the development position by the means, the internal pressure in the toner hopper is reduced.Pressure sensorAs a result, the amount of new toner used is reduced by reusing the recovered toner, the cost per transfer sheet is reduced, and the occurrence of abnormal transport of toner transport to the developing means can be easily determined. It is possible to provide an image forming apparatus that prevents the occurrence of scattering and locking of a gas flow transfer means and damage to the apparatus.
  According to a third aspect of the present invention, the electrostatic latent image formed on the image carrier that carries the formed image is visualized and the toner hopper that supplies toner to the developing means that forms the toner image is provided on the image carrier. Gas flow transfer means and gas for transporting toner as a gas mixture to the air-fuel mixture transport path and the air-fuel mixture transport path using the collected toner that is unlikely to contain foreign matters such as residual paper dust as a gas mixture When the toner is transported from a position away from the development position by the gas supply means for supplying the gas to the flow transfer means, the internal pressure in the toner hopper is detected by the pressure sensor so that the recovered toner can be reused. High quality image, low amount of new toner used, low cost per transfer paper, easy determination of abnormal transport of toner transport to developing means, toner scattering and gas flow transport means It is to be able to provide an image forming apparatus to prevent the occurrence of lock and device damage accident.
[0007]
  According to a fourth aspect of the present invention, toner is supplied to a gas in a toner hopper that replenishes toner to a developing means that visualizes an electrostatic latent image formed on an image carrier that carries a formed image and forms a toner image. As an air-fuel mixture, a toner is transferred from a position away from the developing position by a gas flow transfer means for transferring toner to the air-fuel mixture transfer path and a gas mixture transfer path as a gas mixture and a gas supply means for supplying gas to the gas flow transfer means. When transporting, the internal pressure in the toner hopperPressure sensorAnd detecting the internal pressure in the toner hopper from the time of operation of the gas flow transfer means and the gas supply means, so that the occurrence of abnormal conveyance of the toner conveyance to the developing means can be determined easily and at an early stage. In addition, it is possible to provide an image forming apparatus that prevents the gas flow transfer means from being locked and the occurrence of damage to the apparatus.
  According to a fifth aspect of the present invention, the toner is gas-filled in a toner hopper that replenishes toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms a toner image. As an air-fuel mixture, a toner is transferred from a position away from the developing position by a gas flow transfer means for transferring toner to the air-fuel mixture transfer path and a gas mixture transfer path as a gas mixture and a gas supply means for supplying gas to the gas flow transfer means. When transporting, the internal pressure in the toner hopperPressure sensorWhen detected withbothA pressure sensor for detecting the internal pressure in the toner hopper is arranged above the position of the toner to be accumulated in the toner hopper so that the occurrence of abnormal conveyance of the toner conveyance to the developing means can be easily and accurately determined. It is possible to provide an image forming apparatus that prevents the occurrence of toner scattering, gas flow transfer means locking, and apparatus damage accidents.
[0008]
  According to a sixth aspect of the present invention, the toner is supplied with gas in a toner hopper that replenishes toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms the toner image. As an air-fuel mixture, a toner is transferred from a position away from the developing position by a gas flow transfer means for transferring toner to the air-fuel mixture transfer path and a gas mixture transfer path as a gas mixture and a gas supply means for supplying gas to the gas flow transfer means. When transporting, the internal pressure in the toner hopperPressure sensorIf you detect withbothThe abnormal conveyance determination control means alerts the abnormal conveyance determination result by a warning means, and it is easy to determine the occurrence of abnormal conveyance of the toner conveyance to the developing means, so that the toner scatters and the gas flow transfer means is locked or the device is damaged. An image forming apparatus capable of reliably preventing an accident from occurring can be provided.
  8. The surplus gas flow discharge for discharging the surplus gas flow for replenishing toner to the developing means for visualizing the electrostatic latent image formed on the image carrier carrying the formed image to form a toner image. In the toner hopper having the means, the gas is supplied to the gas flow transfer means and the gas flow transfer means for transferring the toner as a gas mixture to the gas mixture transfer path and the gas mixture transfer path. When the toner is transported from a position away from the development position by the gas supply means, the internal pressure in the toner hopper is reduced.Pressure sensorIn this way, it is possible to easily detect the occurrence of abnormal conveyance of toner to the developing means, and to prevent the occurrence of toner scattering due to the pressure increase in the toner hopper, the lock of the gas flow transfer means, and the damage of the apparatus. To be able to provide the device.
  9. The surplus gas flow discharge for discharging the surplus gas flow for replenishing the toner to the developing means for visualizing the electrostatic latent image formed on the image carrier carrying the formed image and forming the toner image. In a toner hopper having a gas filter of the means, a gas flow transfer means and a gas flow transfer means for transferring the toner as a mixture with the gas to the mixture transfer path and the mixture transfer path as a mixture with the gas When the toner is transported from a position away from the development position by the gas supply means for supplying the gas, the internal pressure in the toner hopper is reduced.Pressure sensorBy detecting the occurrence of abnormal toner conveyance to the developing means, it is possible to easily determine the occurrence of toner scattering due to the pressure increase in the toner hopper, the locking of the gas flow transfer means, and the device damage accident at a low cost. An image forming apparatus capable of preventing the problem can be provided.
  According to a ninth aspect of the present invention, the toner is supplied with gas in a toner hopper that replenishes toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms the toner image. As an air-fuel mixture, a toner is transferred from a position away from the developing position by a gas flow transfer means for transferring toner to the air-fuel mixture transfer path and a gas mixture transfer path as a gas mixture and a gas supply means for supplying gas to the gas flow transfer means. When transporting, the internal pressure in the toner hopperPressure sensorWhen detected withbothBy determining the appropriate replacement time due to clogging of the gas filter by the abnormal transport discrimination control means, it is possible to easily determine the occurrence of abnormal transport of the toner transport to the developing means and the replacement time of the gas filter, and to scatter the toner and gas It is possible to provide an image forming apparatus having a low running cost by preventing the lock of the flow transfer means and the occurrence of an apparatus breakage accident and increasing the replacement interval of the gas filter.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
  Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall schematic diagram showing a digital copying machine of an image forming apparatus as an embodiment of the present invention. This digital copying machine uses a well-known electrophotographic system and has a drum-like image carrier 1 inside. A photoconductor is provided. Around the drum-shaped photosensitive member of the image carrier 1, a charger 11, an exposure unit 12, a developing unit 2, a transfer unit 13, and a cleaning unit that perform an electrophotographic copying process along a rotation direction indicated by an arrow A shown in the drawing. An image carrier cleaning means 9a and a transfer means cleaning means 9b of means 9 are arranged. The exposure means 12 is an electrostatic latent image on the drum-like photosensitive member of the image carrier 1 based on the image signal read by the reading means 15 on the document placed on the document placing table 14 on the upper surface of the apparatus body 0. Form. The electrostatic latent image formed on the drum photoreceptor of the image carrier 1 is visualized by the developing means 2 to form a toner image. On the developing means 2, new toner (Tn) replenished from the new toner container 19, recovered toner (t) recovered by the image carrier cleaning means 9a of the cleaning means 9 and reused, or these A toner hopper 3 that mixes and replenishes the toner is disposed. Waste toner (tt) collected by the cleaning means 9b of the transfer means is collected in the waste toner container 20 and discarded. With the powder screw pump of the gas flow transfer means 5, the new toner (Tn) or the recovered toner (t) is mixed with the gas sent from the gas pump of the gas supply means 6 via the mixture transfer path 4. The toner hopper 3 is transported and conveyed.Inside Pressure detector 7 (pressure sensor 7a)However, when the internal pressure in the toner hopper 3 is detected and the new toner (Tn) or the recovered toner (t) is transported into the toner hopper 3 as a gas mixture with the gas, abnormal transport or excess gas is generated. The exchange time of the flow discharge means 10 is determined. The toner image formed on the drum photoconductor of the image carrier 1 is electrostatically transferred by the transfer means 13 onto the transfer sheet (P) transferred from the paper feeder 16. The transfer sheet (P) to which the toner image is transferred is conveyed and fixed to the fixing means 17 and then discharged to the discharge tray 18 for storage.
[0010]
  FIG. 2 is an enlarged view of the image forming unit, and FIG. 3 is an external perspective view of the developing unit. The developing unit 2 is a two-component developing device and includes a developer composed of a carrier and toner (T) in a developing tank 2a. ing. When the two-component developing device of the developing unit 2 forms a toner image, the toner (T) of the developer is consumed, and the toner density corresponding to the ratio of the toner (T) in the developer is reduced. Therefore, in order to suppress a decrease in image density, when the toner density in the developer becomes a predetermined value or less, the toner (T) is replenished from the toner hopper 3 disposed on the developing means 2 and the developer is contained in the developer. The toner density is maintained. The toner concentration in the developer is measured by a magnetic permeability sensor 2b disposed below the developing tank 2a. The toner (T) replenished from the toner hopper 3 through the replenishing roller 2c is agitated and frictionally charged with the carrier by the agitating member 2d in the developing tank 2a. The developer composed of the carrier and the toner (T) is splashed up to the developing roller 2f by the paddle wheel 2e, and is attracted onto the developing roller 2f by the magnet in the developing roller 2f. The developer is conveyed by the sleeve on the outer periphery of the developing roller 2f, and the excess is scraped off by the developing doctor 2g. The toner (T) in the developer conveyed to the drum-shaped photoconductor side of the image carrier 1 adheres to the electrostatic latent image by a developing bias. The toner (T) adhering to the drum-shaped photoconductor of the image carrier 1 by the development of the developing unit 2 is electrostatically transferred to the transfer paper of the transfer target (P) by the transfer unit 13. About 10% of the toner (T) remains untransferred and remains on the drum-shaped photoconductor of the image carrier 1. Untransferred toner (T) is scraped off from the drum-shaped photosensitive member of the image carrier 1 by the cleaning blade 9a1 of the image carrier cleaning means 9a and the brush roller 9a2 of the cleaning means 9. The untransferred toner (T) thus scraped off falls by its own weight from the discharge port 9a3 to be reused as the recovered toner (t) for recycling, and the powder of the gas flow transfer means 5 is discharged by the toner guide member 9a4. The mixture is transported as a collected toner (t) to the body screw pump and transferred as a mixture with the gas sent from the gas pump of the gas supply means 6 through the mixture conveyance path 4 communicating with the collection toner port 3a. It is conveyed into the toner hopper 3. The toner guide member 9a4 serves as a recovery toner transfer path for sending the recovery toner (t) from the cleaning means 9a of the cleaning means 9 to the screw pump of the gas flow transfer means 5.
[0011]
  In the toner hopper 3, the collected toner port 3 a connected to the air-fuel mixture transport path 4 at the entrance of the collected toner (t), the new toner supply port 3 b for supplying new toner (Tn), and the toner hopper 3 In order to discharge the surplus gas flow, the internal pressure in the toner hopper 3 such as the gas filter 10a of the surplus gas flow discharge means 10 disposed on the upper surface is detected.Pressure sensor7a is provided.By the abnormal conveyance discrimination control means 7b,A detection signal of the internal pressure in the toner hopper 3 of the pressure sensor 7a, which is disposed above the position of the toner (T) accumulated in the toner hopper 3 and prevents erroneous detection. When the toner (T) of the collected toner (t) is transported into the toner hopper 3 as a gas mixture with the gas, it is less expensive than the on / off valve (not shown) of the abnormal gas generation or the surplus gas flow discharge means 10. The replacement time due to the clogging of the gas filter 10a for preventing the scattering of toner is set.Detect and by warning means 7cA warning sound is generated or a warning is displayed.On the other hand,Since the toner (T) adheres to the transfer belt 13a of the transfer means 13 in contact with the drum-shaped photosensitive member of the image carrier 1 in the non-transferred portion or non-image portion, the cleaning means 9 A cleaning means 9b for the transfer means is provided. Residual toner (T) on the transfer belt 13a is scraped off by a cleaning blade 9b1 which is in sliding contact with the transfer belt 13a. Since the toner (T) scraped off from the transfer belt in this way is likely to contain foreign matters such as paper dust, in this example, the toner (T) is not recycled and is discarded as waste toner (tt) from the discharge port 9b2. It falls by its own weight and is collected and discarded into the waste toner container 20 through the toner guide 9b3.
[0012]
  FIG. 4 is an explanatory diagram of the structure of the frame and developing means constituting the skeleton of the image forming apparatus of the present invention, and FIG. 5 is a perspective view of the main part centering on the toner recycling mechanism. A powder screw pump is provided as the gas flow transfer means 5 for transferring the collected toner (t) collected by the image carrier cleaning means 9 a of the cleaning means 9 to the developing means 2. Yes. The powder screw pump as the gas flow transfer means 5 is also referred to as a Mono pump, and is rotated intermittently through the timing belt 0a by the rotational drive from the apparatus main body 0 to collect the recovered toner (t ) And the gaseous air supplied by the gas pump of the gas supply means 6 and is controlled to be intermittently conveyed to the developing means 2 via the mixture conveyance path 4. Has been. For the air-fuel mixture transport path 4, an elastic tube or a somewhat rigid bendable pipe can be advantageously used, but an elastic tube that can be easily installed and can be freely arranged is particularly advantageous.By abnormal conveyance discrimination control means 7bThe new toner replenishing port is a detection signal of the internal pressure in the toner hopper 3 of the pressure sensor 7a which is arranged above the position of the toner (T) accumulated in the toner hopper 3 to prevent erroneous detection. When the new toner (Tn) replenished from 3b or the toner (T) of the recovered toner (t) is transported into the toner hopper 3 as an air-fuel mixture, the occurrence of abnormal transport or the excess gas flow The time for replacement due to clogging of the gas filter 10a of the discharge means 10 is determined.AndA warning sound is generated or a warning is displayed by the warning means 7c arranged on the operation panel 0b.
[0013]
  FIG. 6 is a cross-sectional view of the powder screw pump. The powder screw pump as the gas flow transfer means 5 is also called a mono pump, and includes a stator 5b fixed to a holder 5a and the stator. A rotor 5c that moves the collected toner in the axial direction by rotating in contact with 5b, and the stator 5b is disposed so as to wrap around the rotor 5c. The rotor 5c is engaged with the shaft of the lateral conveying screw 5d. The other end of the lateral conveying screw 5d engages with a seal member 5e, a bearing 5f, and a clutch 5g, and rotational driving from the apparatus main body 0 is performed via the timing belt 0a, timing pulley 5h, and clutch 5g. 5c, the horizontal conveying screw 5d is driven to rotate. The powder screw pump as the gas flow transfer means 5 starts to rotate by the ON operation of the micro processing unit (MPU) 5i, starts the transfer operation of the recovered toner (t), and then rotates for a predetermined time. Control is performed so that the recovered toner transfer operation is intermittently performed by driving to stop and intermittently rotating to stop the recovery toner transfer operation. The stator 5b is made of an elastic body such as a rubber material, and the inner peripheral surface wraps around the rotor 5c. There is a gap 5j of about 1 mm between the outer peripheral surface and the inner peripheral surface of the holder 5a, and leads to the toner passage 5k. Yes. The mixture passage 4 connected to the developing means 2 is connected to the toner passage 5k. As the air-fuel mixture transport path 4, an elastic tube or a somewhat rigid bendable pipe can be used advantageously, but an elastic tube that is easy to install and can be freely arranged is particularly advantageous. The powder screw pump as the gas flow transfer means 5 is provided with a gas supply port 5l for blowing gaseous air sent from the gas pump of the gas supply means 6 into the toner passage 5k from the gap 5j. ing. In the above configuration, when the powder screw pump 5 and the gas supply means 6 are operated, the mixture of the collected toner and air is conveyed to the toner hopper 3, so that the internal pressure in the toner hopper 3 increases at a stroke during normal operation. . The pressure sensor 7 a detects the pressure in the toner hopper 3. For example, when the internal pressure is 2 kPa or less, the signal is low, and when the internal pressure is 2 kPa or more, the signal is set to low → The signal changes to “high → low” as the operation of the gas supply unit 6 ends. Such signal changes occur during normal operation. On the other hand, when toner conveyance is abnormal, the internal pressure in the toner hopper does not change due to toner clogging, air backflow, gas flow supply means failure, and the like. Therefore, even if the gas flow supply means is turned ON / OFF, if the signal remains low, it is determined that the toner conveyance is abnormal, and the machine is stopped and an abnormality is displayed. Further, the filter 10 plays a role of releasing excess air flow, and prevents toner scattering due to an abnormal increase in internal pressure in the toner hopper 3. When the filter becomes clogged, the internal pressure in the hopper 3 rises more than usual, and the decrease time of the internal pressure after the gas supply means 6 stops becomes longer, and the signal from the pressure sensor 7a also has a high time. It becomes longer than usual. At this time, it is determined that the magnetic field of the filter is changed, and a display for prompting the replacement of the filter is performed.
[0014]
  FIG. 7 is a flowchart showing an example of the toner transfer operation by the gas flow transfer means and the pressure detection operation associated therewith. The image forming operation is performed, and the toner (T) is mixed into the toner hopper 3 as a gas mixture. The occurrence of abnormal conveyance during conveyance and the determination of the replacement time of the gas filter 10a of the surplus gas flow releasing means 10 are performed so that warning sound is generated or displayed on the warning means 7c.Abnormal conveyance discrimination control means 7bWorks. That is, the powder screw pump as the gas flow transfer means 5 starts (ON) the toner transfer operation for starting the rotation drive by the micro processing unit (MPU) 5i and transferring the toner (T). (Step 1), the gas pumping operation for blowing gas into the powder screw pump as the gas flow transfer means 5 by the gas pump of the gas supply means 6 is started (ON) (see FIG. 8a). (Step 2), it is detected whether the detection signal of the pressure sensor 7a is “high” (Step 3). For example, when the internal pressure in the toner hopper 3 is 2 kPa or less, “Low”, 2 kPa or more If the detection signal of the pressure sensor 7a is “low”, the toner (T) is clogged, the gas flows backward, the gas pump of the gas supply means 6 is set. Since the internal pressure in the toner hopper 3 does not change due to a failure or the like, it is determined as “toner abnormal conveyance” (see c in FIG. 8), and the powder screw pump as the gas flow transfer means 5 is The powder screw pump as the gas flow transfer means 5 is stopped (OFF) by stopping the toner transfer operation for transferring the toner (T) by stopping the rotational drive by the micro processing unit (MPU) 5i (step 4). The gas blowing operation for blowing the gas into is stopped (OFF) (step 5), and the warning means 7c arranged on the operation panel 0b generates a warning sound or displays a warning. (Step 6), the process ends.
[0015]
  However, if step 3 is Yes, that is, if the detection signal of the pressure sensor 7a is “high”, it is determined as “normal operation” (see FIG. 8b), and the powder as the gas flow transfer means 5 is determined. The screw pump stops the rotational drive by controlling the micro processing unit (MPU) 5i for 2 seconds and then stops the toner transfer operation for transferring the toner (T), and then stops (step 7). . Moreover, the gas supply means 6 stops, after continuing gas blowing operation for blowing gas into a powder screw pump for 6 seconds (step 8). Then, it is determined whether or not the detection signal of the pressure sensor 7a is “low” (step 9). Here, when the detection signal is “low”, the gas filter 10 a of the surplus gas flow releasing means 10 serves to release the surplus air flow, and the toner scatters due to an abnormal increase in internal pressure in the toner hopper 3. Is preventing. When the gas filter 10a becomes clogged, the internal pressure in the toner hopper 3 rises more than usual, and the internal pressure after the toner transfer operation of the powder screw pump as the gas flow transfer means 5 is stopped. , The detection time of the pressure sensor 7a becomes “high”, and the “high” time becomes longer than usual. Therefore, at this time, the detection signal of the pressure sensor 7a is detected to be “low”, and the process ends. However, when the detection signal of the pressure sensor 7a is detected as "high" and the "replacement time" due to the clogging of the gas filter 10a is determined (see d of FIG. 8), it is arranged on the operation panel 0b. A warning sound is generated or displayed on the warning means 7c for “replacement” of the gas filter 10a (step 10), and the process ends.
[0016]
【The invention's effect】
  Since the present invention is configured as described above, according to the first aspect of the present invention, a toner image is formed by developing an electrostatic latent image formed on an image carrier that carries a formed image. In the toner hopper for supplying toner to the developing means, the gas flow transfer means and the gas flow transfer for transferring the toner as a mixture with the gas to the mixture transfer path and the mixture transfer path as a mixture with the gas. When the toner is transported from a position away from the development position by the gas supply means for supplying gas to the means, the internal pressure in the toner hopper is reduced.Pressure sensorTherefore, it is possible to provide an image forming apparatus that can easily determine the occurrence of abnormal conveyance of toner to the developing unit and prevent the occurrence of toner scattering, gas flow transfer unit locking, and device damage accidents. Can be done. Further, in the toner hopper that replenishes the toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms the toner image, the toner is mixed with the gas, When the toner is transported from a position away from the developing position by the gas flow transfer means for transferring the toner to the gas mixture transfer path and the gas mixture transfer path and the gas supply means for supplying the gas to the gas flow transfer means. The internal pressure in the toner hopperPressure sensorWhen detected withbothThe abnormal conveyance discrimination control means discriminates the occurrence of abnormal conveyance of the mixture of toner and gas from the detection signal of the internal pressure of the pressure sensor, so it is easier to determine the occurrence of abnormal conveyance of toner conveyance to the developing means. As a result, it is possible to provide an image forming apparatus that prevents the occurrence of toner scattering, gas flow transfer means locking, and apparatus damage accidents.
  According to the second aspect of the present invention, image formation is performed in the toner hopper that replenishes toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms the toner image. The recovered toner collected by the cleaning means later is used as a gas mixture, and gas is supplied to the gas mixture transfer path and the gas mixture transfer path to supply gas to the gas flow transfer means and the gas flow transfer means. When the toner is transported from a position away from the development position by the gas supply means, the internal pressure in the toner hopper is reduced.Pressure sensorBecause the amount of new toner used is reduced by reusing recovered toner and the cost per transfer sheet is reduced, it is easy to determine the occurrence of abnormal transport of toner to the developing means. It has become possible to provide an image forming apparatus that prevents the occurrence of toner scattering, gas flow transfer means locking, and apparatus damage accidents.
  According to the third aspect of the present invention, the image carrier is provided in the toner hopper that replenishes toner to the developing means that visualizes the electrostatic latent image formed on the image carrier carrying the formed image and forms the toner image. Gas flow transfer that transports toner as an air-fuel mixture to the air-fuel mixture transport path and the air-fuel mixture transport path using the recovered toner that is unlikely to contain foreign matters such as paper dust remaining on the body as a gas-air mixture When the toner is transported from a position away from the developing position by the gas supply means for supplying gas to the means and the gas flow transfer means, the internal pressure in the toner hopper isPressure sensorTherefore, even if the collected toner is reused, the formed image is high quality, the amount of new toner used is small, the cost per transfer sheet is low, and the toner transport to the developing means is abnormal. Thus, it is possible to provide an image forming apparatus that can easily determine the occurrence of toner and prevent the occurrence of toner scattering, gas flow transfer means locking, and apparatus damage accidents.
[0017]
  According to the fourth aspect of the present invention, the toner is put in the toner hopper that replenishes toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms the toner image. Separated from the development position by the gas supply means for supplying the gas to the gas flow transfer means and the gas flow transfer means for transferring the toner as the gas mixture to the gas mixture transfer path and the gas mixture transfer path as the gas mixture with the gas When transporting toner from the position, the internal pressure in the toner hopperPressure sensorWhen detected withbothSince the internal pressure in the toner hopper is detected from the time of operation of the gas flow transfer means and the gas supply means, the occurrence of abnormal conveyance of the toner conveyance to the developing means can be easily and early determined to determine toner scattering and gas flow. It has become possible to provide an image forming apparatus that prevents the locking of the transfer means and the occurrence of an apparatus damage accident.
  According to the fifth aspect of the present invention, the toner is placed in the toner hopper that replenishes the toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms the toner image. Separated from the development position by the gas supply means for supplying the gas to the gas flow transfer means and the gas flow transfer means for transferring the toner as the gas mixture to the gas mixture transfer path and the gas mixture transfer path as the gas mixture with the gas When transporting toner from the position, the internal pressure in the toner hopperPressure sensorWhen detected withbothSince the pressure sensor that detects the internal pressure in the toner hopper is arranged above the position of the toner that accumulates in the toner hopper, it can easily and accurately determine the occurrence of abnormal conveyance of toner to the developing means. Thus, it is possible to provide an image forming apparatus that prevents the occurrence of toner scattering, gas flow transfer means locking, and apparatus damage accidents. According to the sixth aspect of the present invention, the toner is put in the toner hopper that replenishes toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms the toner image. Separated from the development position by the gas supply means for supplying the gas to the gas flow transfer means and the gas flow transfer means for transferring the toner as the gas mixture to the gas mixture transfer path and the gas mixture transfer path as the gas mixture with the gas When transporting toner from the position, the internal pressure in the toner hopperPressure sensorIf you detect withbothSince the abnormal conveyance determination result of the abnormal conveyance determination control means is warned by the warning means, the occurrence of abnormal conveyance of toner conveyance to the developing means can be easily determined to lock the toner scattering and gas flow transfer means and the device It has become possible to provide an image forming apparatus that reliably prevents the occurrence of damage accidents.
[0018]
  According to the seventh aspect of the present invention, the surplus gas flow for replenishing the toner to the developing means for visualizing the electrostatic latent image formed on the image carrier carrying the formed image and forming the toner image is discharged. In a toner hopper having a gas flow release means, a gas flow transfer means and a gas flow transfer means for transferring toner as a gas mixture to a gas mixture transfer path and a gas mixture transfer path as a gas mixture with a gas When the toner is transported from a position away from the development position by the gas supply means for supplying the gas, the internal pressure in the toner hopper is reduced.Pressure sensorTherefore, it is easy to determine the occurrence of abnormal transport of toner to the developing means, and to prevent the occurrence of toner scattering due to pressure increase in the toner hopper, the lock of the gas flow transport means, and the damage of the device. A forming apparatus can be provided.
  According to the eighth aspect of the present invention, the surplus gas flow for replenishing the toner to the developing means for visualizing the electrostatic latent image formed on the image carrier carrying the formed image and forming the toner image is discharged. In a toner hopper having a gas filter of a gas flow releasing means, a gas flow transfer means and a gas flow for transferring toner as a mixture with a gas to a mixture transfer path and a mixture transfer path as a mixture with a gas. When the toner is transported from a position away from the development position by the gas supply means for supplying gas to the transfer means, the internal pressure in the toner hopper is reduced.Pressure sensorTherefore, it is possible to easily determine the occurrence of abnormal toner conveyance to the developing unit and reliably prevent toner scattering due to pressure increase in the toner hopper, gas flow transfer unit locking, and device damage accidents at low cost. It is now possible to provide an image forming apparatus that prevents the above.
  According to the ninth aspect of the present invention, the toner is placed in the toner hopper that replenishes the toner to the developing means that visualizes the electrostatic latent image formed on the image carrier that carries the formed image and forms the toner image. Separated from the development position by the gas supply means for supplying the gas to the gas flow transfer means and the gas flow transfer means for transferring the toner as the gas mixture to the gas mixture transfer path and the gas mixture transfer path as the gas mixture with the gas When transporting toner from the position, the internal pressure in the toner hopperPressure sensorWhen detected withbothSince the proper conveyance timing due to the clogging of the gas filter is determined by the abnormal conveyance discrimination control means, the occurrence of abnormal conveyance of the toner conveyance to the developing means and the replacement timing of the gas filter can be easily determined to determine whether the toner is scattered. It has become possible to provide an image forming apparatus having a low running cost by preventing the occurrence of a gas flow transfer means lock and an apparatus breakage accident, and a longer gas filter replacement interval.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating an outline of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view for explaining a main part of an image forming apparatus showing an embodiment of the present invention.
FIG. 3 is a perspective view illustrating another main part of the image forming apparatus according to the embodiment of the present invention.
FIG. 4 is a perspective view for explaining another main part of the image forming apparatus according to the embodiment of the present invention.
FIG. 5 is a developed perspective view illustrating another main part of the image forming apparatus according to the embodiment of the present invention.
FIG. 6 is an explanatory diagram illustrating another main part of the image forming apparatus according to the embodiment of the present invention.
FIG. 7 is a flowchart for explaining the operation of another main part of the image forming apparatus according to the embodiment of the present invention.
G.
FIG. 8 illustrates the operation timing of other main parts of the image forming apparatus according to the exemplary embodiment of the present invention.
Timing chart.
[Explanation of symbols]
  0 Device body, 0a Timing belt, 0b Operation panel
  1 Image carrier
  2 developing means, 2a developing tank, 2b magnetic permeability sensor, 2c replenishing roller, 2d stirring member, 2e paddle wheel, 2f developing roller, 2g developing doctor
  3 Toner hopper, 3a Collected toner port, 3b New toner supply port
  4 Mixture transport path
  5 Gas flow transfer means, 5a holder, 5b stator, 5c rotor, 5d lateral conveying screw, 5e seal member, 5f bearing, 5g clutch, 5h timing pulley, 5i micro processing unit (MPU), 5j clearance, 5k toner passage 5 l Gas supply port
  6 Gas supply means
  7a Pressure sensor, 7b Abnormal conveyance discrimination control means, 7c Warning means
  DESCRIPTION OF SYMBOLS 9 Cleaning means, 9a Image carrier cleaning means, 9a1 cleaning blade, 9a2 brush roller, 9a3 discharge port, 9a4 toner guide member, 9b Transfer means cleaning means, 9b1 cleaning blade, 9b2 discharge port, 9b3 toner guide member
10 Excess gas flow discharge means, 10a Gas filter
11 Charger
12 Exposure means
13 Transfer means, 13a Transfer belt
14 Document table
15 Reading means
16 Paper feeder
17 Fixing means
18 Output tray
19 New toner container
20 Waste toner container

Claims (9)

In an electrophotographic image forming apparatus that forms an image by supplying toner as a gas mixture with an electrostatic latent image formed on an image carrier from a position away from the development position, the image carrier that carries the formed image A developing means for visualizing the electrostatic latent image formed on the image bearing member to form a toner image, a toner hopper for supplying toner to the developing means, and a toner hopper for supplying toner and gas to the toner hopper. An air-fuel mixture transport path for transporting an air-fuel mixture, a gas flow transport means for transporting toner to the air-fuel mixture transport path as a gas mixture, a gas supply means for supplying gas to the gas flow transport means, and the toner A pressure sensor for detecting the internal pressure in the hopper,
An image forming apparatus comprising: an abnormal conveyance determination control unit configured to determine occurrence of abnormal conveyance of a mixture of toner and gas based on an internal pressure detection signal from the pressure sensor.   2. The image forming apparatus according to claim 1, wherein the gas flow transfer unit transfers the collected toner collected by the cleaning unit after image formation.   3. The image forming apparatus according to claim 2, wherein the cleaning unit collects toner remaining on the image carrier.   4. The image forming apparatus according to claim 1, wherein the pressure sensor detects an internal pressure in the toner hopper from the time of operation of the gas flow transfer means and the gas supply means. apparatus.   5. The image forming apparatus according to claim 1, wherein a pressure sensor for detecting an internal pressure in the toner hopper is disposed above a position of toner accumulated in the toner hopper. Image forming apparatus.   6. The image forming apparatus according to claim 5, further comprising a warning unit that warns of an abnormal conveyance determination result by the abnormal conveyance determination control unit.   7. The image forming apparatus according to claim 1, wherein the toner hopper includes a surplus gas flow discharge unit that discharges a surplus gas flow.   8. The image forming apparatus according to claim 7, wherein the surplus gas flow discharge means is a gas filter. 9. The image forming apparatus according to claim 8, wherein a replacement time of the gas filter is determined by the abnormal conveyance determination control means.

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