JP2008298910A - Developing device and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of preventing a background from being soiled due to entry of paper powder into the developing device or an accumulation of paper powder without increasing the size and cost of the device, and to provide an image forming apparatus using the developing device. <P>SOLUTION: The developing device includes: stir members 19 and 22 for stirring toner supplied inside; a conveying means by which residual toner recovered by a cleaning means 14 used for recovering transfer residual toner on an image carrier 3 is conveyed inside for recycling; and a drive means for rotating the stir members with a prescribed timing in reverse direction to that used for development. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing device and an image forming apparatus using the developing device.

JP 2003-195714 A

  In recent image forming apparatuses, the toner developed on the photosensitive drum remains on the photosensitive drum without being transferred to the paper in view of environmental problems such as reduction of running cost and waste disposal. An apparatus adopting a so-called “reclaim system” in which transfer residual toner is collected by a cleaning device, and the toner collected by the cleaning device is returned to the developing device and reused is used.

  By the way, in the image forming apparatus employing such a “reclaim method”, the toner that has been collected and discarded by the cleaning device can be effectively used again for development, but is once developed on the photosensitive drum. The toner collected later contains paper powder made of additives such as paper fibers and kaolin adhering to the surface of the photosensitive drum. Therefore, in the case of an image forming apparatus adopting the above “reclaim method”, if the paper is used for a long period of time, the paper dust of the paper is collected in the developing unit together with the collected toner, and mixed and accumulated in the developing unit. As a result, background stains (fogging) may occur on the print. Paper dust consisting of the above-mentioned paper fibers and additives tends to be positively charged with the opposite polarity to the toner charged with negative polarity, and the toner is electrostatically attached around the paper dust. When the paper dust mixed / accumulated in the developing device is supplied to the development area, the paper dust adheres to the background portion on the print together with the toner, and dot or line background stain (fogging) occurs. It appears.

  As described above, the background stain (fogging) generated by mixing and accumulating paper dust in the developing device causes the paper dust to enter the developing device as the amount of use of the image forming unit of the image forming apparatus increases. The accumulated paper tends to worsen, and most of the paper dust accumulates between the agitating member such as an auger in the developing device and the bottom surface of the developing device housing, and goes to the development area as the amount of paper dust increases. And cause background stains (fogging).

  The gap between the agitating member such as an auger in the developing device and the bottom surface of the developing device housing is normally set to about 1 to 1.5 mm, and shaft runout during the rotation of the auger, warpage or the like in the developing device housing occurred. Even in such a case, the two are configured so as not to interfere with each other. If the gap is narrowed, a so-called “toner grid” in which the toner is aggregated by receiving mechanical pressure by the auger is likely to occur. For this reason, by setting the gap between the agitator such as an auger and the bottom surface of the developer housing narrow, paper dust that tends to accumulate between the auger in the developer device and the bottom surface of the developer housing is reliably conveyed by the auger. It is also difficult to take measures to suppress the occurrence of background stains (fogging) by making it possible and preventing the accumulation of paper dust.

  The auger is driven to rotate in one direction, and the toner in the developer is pressed toward the bottom of the developer housing according to the shape of the blades of the auger. Easy to accumulate. However, during normal image formation, the paper powder accumulated at the bottom of the developing device housing is less susceptible to the auger transport force, and it is difficult to transport the paper powder with the auger and discharge it to the outside for recovery. is there.

  Furthermore, background stains (fogging) caused by the accumulation of paper dust in the developing device may occur when the image forming apparatus is vibrated by an external force, such as when the main body cover is opened or closed or when the paper feed cassette is replaced. It tends to occur after the image forming apparatus has been left for a long time.

  The reason is that when the image forming apparatus is vibrated by an external force, the paper dust accumulated on the bottom surface of the developer housing is likely to float due to the vibration, and is mixed with the developer present around the auger by the rotation of the auger. This is because the toner is supplied to the developing area by the developing roll and developed on the photosensitive drum.

  Further, in a normal use state of the image forming apparatus, the developer in the developing device is stirred by the auger, so that voids exist between the particles of the developer, and the so-called fluffy state has a low bulk density. However, after the image forming apparatus has been left for a long period of time, the developer in the developing device becomes bulky due to its own weight and becomes clogged with the developer, and the paper accumulated on the bottom surface of the developing device housing. This is because the powder is easily moved by the pressure of the developer due to the rotation of the auger and is supplied to the developing roll and is developed on the photosensitive drum.

  Therefore, as a technique capable of preventing background contamination (fogging) due to mixing and accumulation of paper dust in the developing device, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 2003-195714 has already been disclosed. .

  The cleaning device according to Japanese Patent Application Laid-Open No. 2003-195714 develops an electrostatic latent image formed on a photoconductor with toner, electrostatically transfers it to a sheet, and then removes the toner remaining on the photoconductor. In the cleaning device of the image forming apparatus provided with a recovery mechanism that recovers and removes the paper dust of the paper adhered on the photoconductor, a supply mechanism for supplying other toner to the toner recovered by the recovery mechanism is provided. The apparatus further comprises a separating unit for separating the paper dust in the toner collected by the collecting mechanism, and the replenishing mechanism is configured to replenish the toner from which the paper dust has been separated by the separating unit. Is included.

  By the way, the problem to be solved by the present invention is that it is possible to prevent background stains from occurring due to paper dust being mixed and accumulated in the developing device without causing an increase in size and cost of the device. A developing device and an image forming apparatus using the same are provided.

That is, the invention described in claim 1 includes a stirring member that stirs the toner supplied inside,
A transfer means for transferring the transfer residual toner collected by the cleaning means for collecting the transfer residual toner remaining on the image carrier to the inside for reuse;
A developing device comprising drive means for rotating the stirring member at a predetermined timing in a direction opposite to that during development.

According to a second aspect of the present invention, there is provided a developing means for developing an electrostatic latent image formed on an image carrier, comprising a stirring member that stirs the toner supplied inside.
Cleaning means for recovering transfer residual toner remaining on the image carrier;
A transfer means for transferring the transfer residual toner collected by the cleaning means to the inside of the developing means for reuse by the developing means;
An image forming apparatus comprising: a driving unit that rotates the stirring member of the developing unit at a predetermined timing in a direction opposite to that during development.

  Furthermore, the invention described in claim 3 is characterized in that the driving means rotationally drives the stirring member in a direction opposite to that during development at the end of the image forming operation or at the time of non-image formation. The image forming apparatus described in the above.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the driving unit makes the rotational speed of the stirring member different from that during normal image formation. .

  Furthermore, the invention described in claim 5 is characterized in that the driving means changes a rotation amount for rotating the stirring member in a direction opposite to that during development based on a usage amount of the image forming apparatus. An image forming apparatus according to claim 3.

  According to a sixth aspect of the present invention, the drive means changes the rotation time for rotating the stirring member in the reverse direction at a speed different from that during development based on the amount of use of the image forming apparatus. The image forming apparatus according to claim 4.

  Further, in the invention described in claim 7, the driving means drives at least one of the image carrier and the developing means, and at least one of the image carrier and the stirring member is simultaneously developed. The image forming apparatus according to claim 2, wherein the image forming apparatus is driven to rotate in a direction opposite to that of the image forming apparatus.

  The invention described in claim 8 is characterized in that the driving means rotates and drives members excluding the developer carrying member in the direction opposite to that during development. This is an image forming apparatus.

  According to the first aspect of the present invention, the driving member rotates the stirring member in a direction opposite to that at the time of development at a predetermined timing, so that the size of the apparatus is not increased and the cost is not increased. The mixed paper dust can be discharged, and it is possible to prevent background stains from occurring by mixing and accumulating in the developing device.

  According to the second aspect of the present invention, the agitating member is rotationally driven in a direction opposite to that during development at a predetermined timing by the driving means, so that the size of the apparatus is not increased and the cost is not increased. The mixed paper dust can be discharged, and it is possible to prevent background stains from occurring by mixing and accumulating in the developing device.

  According to the third aspect of the present invention, paper dust mixed in the developing device can be discharged without increasing the size and cost of the device and without affecting the image forming operation. It is possible to prevent background stains from occurring by mixing and accumulating in the developing device.

  According to the invention described in claim 4, paper dust mixed in the developing device can be discharged more efficiently without causing an increase in size and cost of the device, and mixed and accumulated in the developing device. As a result, it is possible to prevent background stains from occurring.

  According to the invention described in claim 5, paper dust mixed in the developing device can be discharged in accordance with the amount of toner collected without increasing the size and cost of the device. It is possible to prevent the occurrence of background stains by mixing and accumulating.

  According to the invention described in claim 6, paper dust mixed in the developing device can be discharged according to the amount of toner collected without causing an increase in size and cost of the device. It is possible to prevent the occurrence of background stains by mixing and accumulating.

  According to the seventh aspect of the invention, it is possible to remove the toner and the like accumulated in the cleaning means, and it is possible to maintain good cleaning performance.

  According to the eighth aspect of the present invention, it is possible to prevent a problem from occurring when the developer carrying member is driven to rotate in the direction opposite to that during development.

  Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1
FIG. 2 shows a monochrome printer as an image forming apparatus to which the developing device according to Embodiment 1 of the present invention is applied.

  In FIG. 2, reference numeral 1 denotes a printer main body, and a process cartridge 2 as an image forming unit is disposed inside the printer main body 1. The process cartridge 2 is configured to be detachable from the printer main body 1 in order to improve maintenance by the user, and can be easily replaced by the user.

  As shown in FIG. 1, the process cartridge 2 includes a photoconductive drum 3 as an image carrier. The photoconductive drum 3 is coated with a photoconductive material such as OPC on the outer peripheral surface of a metal cylinder. It is configured as described above, and is driven to rotate at a predetermined speed along the direction of the arrow by a driving means described later. The surface of the photosensitive drum 3 is uniformly charged to a predetermined potential by the charging roll 4, and then subjected to image exposure according to the image data by the writing device 5, and an electrostatic latent image corresponding to the image data is generated. It is formed. The electrostatic latent image formed on the photosensitive drum 3 is visualized by the developing device 6 to become a toner image, and the toner image is transferred onto the paper 8 by the transfer roll 7. The paper 8 is supplied in a state in which a predetermined size and a predetermined material are separated from the paper feed tray 9 one by one by a pair of paper feed rolls 10, and is passed through a resist roll (not shown) and a photosensitive drum. 3 is transferred to the transfer position 3 at a predetermined timing.

  The paper 8 on which the toner image has been transferred is separated from the surface of the photosensitive drum 3 and then conveyed to the fixing device 11, where the unfixed toner image is transferred onto the paper 8 by heat and pressure. And discharged onto the discharge tray 13 provided at the upper end of the printer main body 1 with the image surface down.

  Further, the transfer residual toner remaining on the surface of the photosensitive drum 3 without being transferred onto the paper 8 is removed by the cleaning blade 15 of the cleaning device 14 and, as will be described later, is transferred to the developing device 6 through the conveying means. The printer is transported and used again in the development process, and the printer according to the present embodiment employs a so-called “reclaim system”.

  FIG. 1 shows the main part of the process cartridge.

  As shown in FIG. 1, the process cartridge 2 includes a photosensitive drum 3, a charging roll 4, a developing device 6, and a cleaning device 14. As shown in FIG. 1, the developing device 6 is provided with a developing roller 18 as a developer carrying member that is rotatable in an arrow direction in an opening 17 provided on the photosensitive drum 3 side of the developing housing 16. A supply auger 19 is disposed on the back side of the developing roll 18 as stirring means for transporting the developer while stirring, and a partition plate 20 is provided on the back side of the supply auger 19. A stirring auger 22 is provided as a stirring means for transporting the developer 21 while stirring the developer 21. The developer 21 may be a one-component developer composed only of toner or a two-component developer composed of toner and carrier. In this embodiment, the developer 21 includes two components composed of toner and carrier. The component developer 21 is used.

  Further, as shown in FIG. 1, a toner cartridge 23 for supplying toner to the developing device 6 is disposed on the back side of the developing housing 16 of the developing device 6. Is detachably mounted on a cartridge receiver 24 disposed inside the housing. The toner cartridge 23 communicates with a toner supply notification 25 for supplying toner into the developing housing 16 via a shutter (not shown) provided on the bottom surface of the toner cartridge 23 so as to be freely opened and closed. Is opened at the upper end on the back side of the developing housing 16. Further, a toner supply member 26 made of an agitator or the like is rotatably disposed inside the toner supply passage 25, and the toner supply member 26 is rotated to drive the toner supply passage 25 from the toner cartridge 23. In this way, the toner is supplied to the inside of the developing housing 16 of the developing device 6 at a predetermined timing.

  In the developing device 6, the toner supplied from the toner cartridge 23 is conveyed to the downstream side in the conveying direction of the stirring auger 22 while being stirred with the developer 21 in the developing housing 16 by the stirring auger 22. The developer 21 delivered to the supply auger 19 and supplied to the supply auger 19 is supplied to the developing roll 18 while being agitated and conveyed by the supply auger 19. The developer 21 supplied to the developing roll 18 is transported to a developing area facing the photosensitive drum 3 as the developing roll 18 rotates after the layer thickness is regulated by the layer thickness regulating member 16a. Thus, the electrostatic latent image formed on the surface of the photosensitive drum 3 is visualized.

  Further, as shown in FIG. 1, the cleaning device 14 is provided inside the cleaning device 14 when the amount of residual toner removed from the surface of the photosensitive drum 3 by the cleaning blade 15 reaches a predetermined amount. By rotating the transport auger 27, the transfer residual toner collected in the cleaning device 14 is transported to one end of the cleaning device 14 in the longitudinal direction (direction perpendicular to the drawing).

  Further, as shown in FIG. 3, the transfer residual toner collected by the cleaning device 14 is conveyed to one end portion in the longitudinal direction of the cleaning device 14 into the developing housing 16 of the developing device 6 for reuse. A recovery toner conveyance path 28 serving as a conveyance means is provided in communication with the interior of the cleaning device 14, and a collection toner conveyance member 29, also serving as a conveyance means, rotates inside the collection toner conveyance path 28. It is arranged to be possible. The lower end portion of the collected toner conveyance passage 28 is opened above the supply auger 19 of the developing housing 16.

  The opening 28 a provided in the developing housing 16 is provided corresponding to the most downstream portion of the supply auger 19 along the toner conveyance direction, and is supplied from the collected toner conveyance passage 28 to the inside of the development housing 16. The collected toner is transferred from the supply auger 19 to a stirring auger 22 through a passage (not shown) provided in the partition wall 20, and conveyed to the opposite side in the axial direction by the stirring auger 22. 22 is delivered to the supply auger 19 through a passage (not shown) provided in the partition wall 20.

  Further, the collected toner conveying member 29 provided in the collected toner conveying path 28 is composed of an agitator or the like, and rotates the collected toner conveying member 29 to rotate from the cleaning device 14 via the collected toner conveying path 28. Thus, the collected toner is conveyed to the inside of the developing housing 16 of the developing device 6 at a predetermined timing.

  4 and 5 are a sectional view and a perspective view showing the drive mechanism of the printer. This drive mechanism is provided on the printer body 1 side.

  In FIG. 4, reference numeral 31 denotes an output gear of the first drive motor 30 as a drive source. The output gear 31 of the first drive motor is attached to the end of the photosensitive drum 3 in the axial direction. A photosensitive drum drive gear 32 having a large diameter is engaged. The output gear 31 of the first drive motor is meshed with a developing roll drive gear 35 attached to an end of the developing roll shaft 34 of the developing roll 18 via an idler gear 33, and a supply auger. A supply auger drive gear 36 attached to 19 axial ends is meshed. Further, the supply auger drive gear 36 is engaged with a stirring auger drive gear 37 attached to an end portion of the stirring auger 22 in the axial direction.

  At the time of image formation, the output gear 31 of the first drive motor 30 is rotationally driven along the direction of arrow A by rotating the first drive motor 30, and the output gear of the first drive motor 30 is driven. The photosensitive drum drive gear 32 meshed with 31 rotates the photosensitive drum 3 along the arrow A direction at a predetermined rotational speed.

  Further, by rotating the first drive motor 30, the developing roll drive gear 35, the supply auger drive gear 36, and the stirring auger drive gear 37 that are meshed with the output gear 31 of the first drive motor 30 via the idler gear 33. The developing roll 18, the supply auger 19, and the stirring auger 22 are driven to rotate along the arrow A direction.

  Further, as shown in FIG. 4, a developing roll driving gear 35 is attached to the end of the developing roll shaft 34 of the developing roll 18 via a one-way bearing 38. The one-way bearing 38 can rotate the developing / developing roll shaft 34 so as to transmit the rotational driving force to the developing / developing roll shaft 34 only when the developing roll driving gear 35 is rotationally driven along the arrow A direction. The shaft is supported so that when the developing roll driving gear 35 is rotationally driven in the direction opposite to the arrow A direction, the rotational driving force is not transmitted to the developing and developing roll shaft 34.

  In the above configuration, in a printer to which the developing device according to this embodiment is applied, as shown below, paper dust is mixed and accumulated in the developing means without causing an increase in size and cost of the device. It is possible to prevent background stains from occurring.

  In this printer, as shown in FIG. 2, after the surface of the photosensitive drum 3 is uniformly charged to a predetermined potential by the charging roll 4, the writing device 5 performs image exposure according to the image data. An electrostatic latent image corresponding to the data is formed. The electrostatic latent image formed on the photosensitive drum 3 is visualized by the developing device 6 to form a toner image, and the toner image formed on the photosensitive drum 3 is transferred from the paper feed tray 9. After being transferred onto the paper 7 fed at a predetermined timing by the transfer roll 7, it is fixed by the fixing device 11 and discharged onto the paper discharge tray 13.

  Then, the untransferred toner remaining on the photosensitive drum 3 without being transferred onto the sheet 7 is collected by the cleaning blade 15 of the cleaning device 14 and accumulated inside the cleaning device 14, and is then shown in FIG. As shown in FIG. 3, the toner is transported along the axial direction of the photosensitive drum 3 by the collected toner transport member 27 disposed inside the cleaning device 14, and is disposed at the end of the cleaning device 14 as shown in FIG. The collected toner conveying member 29 is conveyed to the inside of the developing housing 16 of the developing device 6 through the collected toner conveying passage 28.

  By the way, the collected toner that is transported into the developing device 6 and used again in the developing process is removed from the surface of the photosensitive drum 3, and the surface of the photosensitive drum 3 is transferred with a toner image. Since it sometimes comes into contact with the paper 7, the recovered toner is mixed with paper powder made of fibers, additives, and the like of the paper 7 in contact with the surface of the photosensitive drum 3. Therefore, in the developing device 6, together with the collected toner, paper powder made of fibers, additives, and the like of the paper 7 mixed in the collected toner is collected and accumulated as it is.

  Therefore, in the printer according to this embodiment, every time the printing operation is completed, the stirring auger 22 of the developing device 6 is rotationally driven in the direction opposite to that during normal image formation, and then the printer stops. Yes.

  In the printer, as shown in FIG. 6, every time the printing operation is completed, the first drive motor 30 is driven to rotate for a predetermined time in the B direction opposite to the normal printing operation for a predetermined time. After being stopped. When the first drive motor 30 is rotationally driven in the arrow B direction which is the reverse direction, the first drive motor output gear 31 is rotationally driven by the first drive motor 30 along the arrow B direction. The photosensitive drum 3 is rotationally driven along the arrow B direction by the photosensitive drum driving gear 32 meshed with the output gear 31 of the first driving motor.

  Then, as shown in FIG. 1, the transfer residual toner or the like sandwiched between the surface of the photosensitive drum 3 and the edge of the cleaning blade 15 of the cleaning device 14 causes the photosensitive drum 3 to rotate along the arrow B direction. As it is driven, it is removed from the edge portion of the cleaning blade 15 and is again collected by the cleaning blade 15 when the photosensitive drum 3 is rotationally driven in the direction of arrow A, which is the forward direction. Therefore, as compared with the case where the photosensitive drum 3 is always rotated only along the direction of arrow A, it is possible to simultaneously prevent the transfer residual toner from adhering to the edge of the cleaning blade 15 for a long period of time. It becomes possible to do.

  Further, by rotating the first drive motor 30, a developing roll drive gear 35, a supply auger drive gear 36 and a stirring auger drive gear 37 meshed with an output gear 31 of the first drive motor via an idler gear 33. The supply auger 19 and the stirring auger 22 are rotationally driven along the arrow B direction.

  Therefore, the paper dust collected together with the collected toner inside the developing device 6 is between the supply auger 19 and the stirring auger 22 and the bottom surface of the developing housing 16, particularly between the stirring auger 22 on the back side and the bottom surface of the developing housing 16. Although the paper dust stays between them, the paper auger 19 and the stirring auger 22 are rotationally driven in the direction of the arrow B, unlike the normal development shown in FIG. As shown in b), the paper dust staying in the vicinity of the bottom surface of the developing housing 16 by the blades of the stirring auger 22 and the like is stirred and mixed in the reverse direction together with the developer 21 and stirred together with the developer 21 in the subsequent developing process. It is conveyed to the downstream side of the auger 22, supplied to the developing roll 18 through the supply auger 19, developed in small amounts, and discharged to the outside.

  As a result, the paper dust collected together with the collected toner in the developing device 6 is stirred together with the developer 21 each time the supply auger 19 and the stirring auger 22 are rotationally driven along the direction of arrow B, and the subsequent development Since it is discharged outside the developing device 6 in the process, it is not accumulated inside the developing device 6. Since the amount of paper dust discharged to the outside of the developing device 6 is very small, even if the paper dust adheres to the background portion on the print together with the toner, the dotted or linear background portion stains It does not appear as (cover).

  Since the developing roll 18 is attached to the developing roll drive gear 35 via the one-way bearing 38, the developing roll 18 is not rotationally driven in the direction of the arrow B and remains stopped. Therefore, the developing roll 18 is driven to rotate in the direction opposite to that during normal development, and the developer does not leak outside.

  In the first embodiment, at the end of the image forming operation, the supply auger 19 and the stirring auger 22 are configured to rotate in the reverse direction. At the time of image formation, the supply auger 19 and the stirring auger 22 may be configured to be rotationally driven in opposite directions.

Embodiment 2
FIG. 8 shows a second embodiment of the present invention. The same parts as those in the first embodiment will be described with the same reference numerals. In the second embodiment, an image carrier is used as a developing device. It is comprised so that it may drive with a different drive source.

  That is, in the second embodiment, as shown in FIG. 8, the photosensitive drum 3 is driven by a second drive motor (not shown) different from the developing device 6. When a drive motor (not shown) is rotationally driven in the direction of arrow A, the second drive motor output gear 41 provided on the output shaft 40 of the second drive motor is rotationally driven along the direction of arrow A, and the second The photosensitive drum 3 is rotationally driven along the arrow A direction by the photosensitive drum driving gear 32 meshed with the output gear 41 of the driving motor.

  In the second embodiment, as shown in FIG. 9, the second drive motor is stopped when the first drive motor 30 that drives the developing device 6 is rotationally driven in the direction of arrow B, which is the reverse direction. Thus, the photosensitive drum 3 remains in a stopped state.

  Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.

Embodiment 3
10 thru | or shows Embodiment 2 of this invention, The same code | symbol is attached | subjected and demonstrated to the part same as the said Embodiment 1, In this Embodiment 2, a drive means is a stirring member. Is rotated based on the amount of use of the image forming apparatus.

That is, in this third embodiment, as shown in FIG. 10, background stains generated by the accumulation of paper dust in the developing device 6, as understood from the first embodiment described above,
From the start of use of the process cartridge 2 as the image forming unit until the amount of use reaches a certain amount, the amount of paper dust accumulated in the developing device 6 is small, and the background stain level is below the allowable level. It has been found by experiments of the present inventors that the level of background contamination exceeds the allowable level when the amount of the process cartridge 2 used exceeds a predetermined amount.

  Therefore, in the third embodiment, as shown in FIG. 10, the usage amount of the process cartridge 2 as an image forming unit, for example, in the printer shown in FIG. 2, the number of prints and the number of rotations of the photosensitive drum 3 are counted. A counter is provided, and the time for rotationally driving the first drive motor 30 in the direction of arrow B, which is the reverse direction, is changed as shown in FIG. It is configured.

  In the third embodiment, as shown in FIG. 12, until the usage amount of the process cartridge 2 reaches the first threshold value, the first drive motor 30 is in the reverse direction even at the end of the printing operation. When the time for rotating the first drive motor 30 in the arrow B direction, which is the reverse direction, is set to zero without rotating in the arrow B direction, and the usage amount of the process cartridge 2 exceeds the first threshold value In addition, the first drive motor 30 is configured to rotate in the reverse direction for a predetermined time T1.

  In addition, after the usage amount of the process cartridge 2 reaches the first threshold value, the first drive motor 30 is moved in the reverse direction for a predetermined time T1 at the end of the printing operation until the usage amount reaches the second threshold value. The first drive motor 30 is rotated in the reverse direction for a predetermined time T2 at the end of the printing operation after the usage amount of the process cartridge 2 reaches the second threshold value. .

  The rotation control of the first drive motor 30 is executed by a control circuit such as a CPU that controls the operation of the printer.

  Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.

Embodiment 4
FIG. 13 shows a fourth embodiment of the present invention. The same parts as those in the first embodiment will be described with the same reference numerals. In the fourth embodiment, an image carrier and a developing device will be described. The developer carrying member is driven by a different drive source.

  That is, in the fourth embodiment, as shown in FIG. 13, the photosensitive drum 3 and the developing roll 18 of the developing device 6 are driven by the first drive motor 30, and the supply auger 19 of the developing device 6 and the agitation are stirred. The auger 22 is configured to be driven by a second drive motor output gear 50 of a second drive motor (not shown).

  In the fourth embodiment, as shown in FIG. 14, at the end of the printing operation, only the second drive motor (not shown) is rotated at a rotation speed different from that during the printing operation, for example, a speed higher than that during the printing operation. The first drive motor 30 is stopped while being rotated in the reverse direction.

  Therefore, in the fourth embodiment, as shown in FIG. 14, the photosensitive drum 3 and the developing roll 18 of the developing device 6 are not driven in the opposite directions, so that the developer is prevented from leaking. be able to.

  In the fourth embodiment, since the supply auger 19 and the stirring auger 22 can be independently driven, only the supply auger 19 and the stirring auger 22 are driven and developed even when the printer is in a standby state. The agent 21 can be stirred.

  Further, in the fourth embodiment, the time for rotationally driving the supply auger 19 and the stirring auger 22 in different directions at different rotational speeds varies according to the amount of the process cartridge 2 used, as in the third embodiment. It is configured to let you.

  Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.

FIG. 1 is a configuration diagram showing a main part of a printer as an image forming apparatus to which a developing device according to Embodiment 1 of the present invention is applied. FIG. 2 is a block diagram showing a printer as an image forming apparatus to which the developing device according to Embodiment 1 of the present invention is applied. FIG. 3 is a block diagram showing a main part of a printer as an image forming apparatus to which the developing device according to Embodiment 1 of the present invention is applied. 4 is a block diagram showing a drive mechanism of a printer as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 5 is a perspective configuration diagram showing the drive mechanism of the printer as the image forming apparatus according to Embodiment 1 of the present invention. FIG. 6 is an explanatory view showing the operation of a printer as an image forming apparatus to which the developing device according to Embodiment 1 of the present invention is applied. FIG. 7 is an explanatory view showing the operation of a printer as an image forming apparatus to which the developing device according to Embodiment 1 of the present invention is applied. FIG. 8 is a configuration diagram showing a main part of a printer as an image forming apparatus to which the developing device according to Embodiment 2 of the present invention is applied. FIG. 9 is a block diagram showing a main part of a printer as an image forming apparatus to which the developing device according to Embodiment 2 of the present invention is applied. FIG. 10 is a graph showing the state of the printer before applying the developing device according to Embodiment 3 of the present invention. FIG. 11 is a graph showing the operation of a printer to which the developing device according to Embodiment 3 of the present invention is applied. FIG. 12 is a graph showing a state of a printer to which the developing device according to Embodiment 3 of the present invention is applied. FIG. 13 is a block diagram showing a main part of a printer as an image forming apparatus to which the developing device according to Embodiment 4 of the present invention is applied. FIG. 14 is a block diagram showing a main part of a printer as an image forming apparatus to which a developing device according to Embodiment 4 of the present invention is applied.

Explanation of symbols

  2: process cartridge, 3: photosensitive drum, 6: developing device, 19: supply auger, 20: stirring auger, 30: first drive motor (drive means).

Claims (8)

A stirring member for stirring the toner supplied to the inside;
A transfer means for transferring the transfer residual toner collected by the cleaning means for collecting the transfer residual toner remaining on the image carrier to the inside for reuse;
A developing device comprising drive means for rotating the stirring member in a direction opposite to that during development at a predetermined timing. A developing unit that has a stirring member that stirs the toner supplied inside, and that develops the electrostatic latent image formed on the image carrier;
Cleaning means for recovering transfer residual toner remaining on the image carrier;
A transfer means for transferring the transfer residual toner collected by the cleaning means to the inside of the developing means for reuse by the developing means;
An image forming apparatus comprising: a driving unit that rotates the stirring member of the developing unit at a predetermined timing in a direction opposite to that during development. The image forming apparatus according to claim 2, wherein the driving unit rotationally drives the stirring member in a direction opposite to that during development at the end of the image forming operation or during non-image formation. The image forming apparatus according to claim 2, wherein the driving unit makes the rotation speed of the stirring member different from that during normal image formation. The image forming apparatus according to claim 3, wherein the driving unit changes a rotation amount for rotating the stirring member in a direction opposite to that during development based on a usage amount of the image forming apparatus. The image forming apparatus according to claim 4, wherein the driving unit changes a rotation time for rotating the stirring member in a reverse direction at a speed different from that during development based on a use amount of the image forming apparatus. apparatus. The driving unit drives at least one of the image carrier and the developing unit, and simultaneously drives at least one of the image carrier and the stirring member to rotate in a direction opposite to that during development. The image forming apparatus according to claim 2. 8. The image forming apparatus according to claim 2, wherein the driving unit rotationally drives a member excluding the developer carrying member in a direction opposite to that during development.

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