JP2009048112A - Method for controlling conveyance of waste toner for image forming apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent waste toner from overflowing when exchanging a consumable member or the like with simple constitution without shortening of the lives of the consumable member and other equipment constituting an image forming apparatus. <P>SOLUTION: In a method for controlling conveyance of the waste toner for the image forming apparatus 1 which forms an image by an electrophotographic system, the waste toner remaining in conveyance screws 31, 32 and 33 for conveying the waste toner is discharged to the outside by controlling so that driving time of the conveyance screws 31, 32 and 33 may be longer when detecting that the life of an imaging unit U or a transfer belt unit TU attached to be exchangeable in an apparatus main body 10 ends than that in ordinary image forming operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a waste toner conveyance control method and an image forming apparatus in an image forming apparatus that forms an image by electrophotography.

  In an image forming apparatus that forms an image by an electrophotographic method, such as a copying machine, a printer, a facsimile machine, a multifunction machine, or a multi-function machine called MFP (Multi Function Peripherals), an electrostatic image formed on a photosensitive drum is used. The latent image is developed to form a toner image, the toner image is primarily transferred to an intermediate transfer belt, further transferred to a recording sheet, and then fixed, and image formation is performed.

  In such an image forming apparatus, there is an apparatus in which a portion for forming a toner image for each color of Y, M, C, and K is unitized as an imaging unit to facilitate replacement and maintenance. In this case, the imaging units of the respective colors are positioned as independent consumable members (consumables), and are exchanged when the service life is reduced by use.

  Further, the transfer belt unit for performing the intermediate transfer is also positioned as a consumable member like the imaging unit, and is replaced when the lifetime is reached.

  By the use of these imaging units and transfer belt units, waste toner is generated inside. The generated waste toner is discharged to the outside by a toner transport screw (toner recovery screw) provided inside, and a part of the waste toner is further transported by an external transport member and put in a waste toner box.

  However, when the imaging unit, the transfer belt unit, or the like is replaced, there is a possibility that waste toner remaining inside these units spills and stains the inside of the apparatus.

  As a countermeasure, the toner transport screw provided in the imaging unit is designed to prevent residual waste toner from spilling out from the joint with the transport member when the imaging unit is pulled out of the main unit for replacement. A mechanical shutter mechanism is provided.

In addition, in an image forming apparatus having a recycling means for returning the toner collected by the cleaning device to the developing device, it is proposed to provide means for discharging the toner in the recycling means into the developing device when the developer is replaced ( Patent Document 1).
JP-A-10-214012

  However, in the conventional mechanical shutter mechanism described above, when the waste toner is accumulated in the coupling portion, the shutter mechanism is not completely closed when the imaging unit is started to be pulled out from the main body. Accumulated waste toner may spill out and stain the interior of the machine.

  Further, Patent Document 1 features a toner recycling system, which returns toner remaining in a toner conveyance path for recycling into the developing device. Therefore, it is possible to prevent the toner density control from being affected by the toner in the recycling unit, but it is not possible to prevent waste toner from spilling when the imaging unit or the like is replaced.

  In order to cope with this problem, it is conceivable to execute a cleaning mode for discharging waste toner remaining in the toner conveyance path in the apparatus when specific information is written in the backup memory of the imaging unit. . However, there is a problem at what timing such specific information is written. For example, when the cleaning mode is frequently executed, the life of the device is shortened.

  Further, it is conceivable that the toner conveying screw and the conveying member are operated after the waste toner is generated until it is collected in the waste toner box. However, many waste toner transport mechanisms operate using a driving force of a process motor or the like, and operating the process motor only for waste toner transport is from the point of view of the life of the consumable member. Is also not preferred.

  The present invention has been made in view of the above-described problems, and waste toner can be removed when replacing a consumable member or the like with a simple configuration without shortening the life of the consumable member and other devices constituting the image forming apparatus. The purpose is to prevent spills.

  A method according to the present invention is a waste toner conveyance control method in an image forming apparatus that forms an image by an electrophotographic method, and it is detected that a consumable member that is replaceably mounted in the apparatus main body has reached the end of its life. In this case, the driving time of the conveying screw for conveying the waste toner is controlled to be longer than the driving time in the normal image forming operation, thereby discharging the waste toner remaining in the conveying screw to the outside. To do.

  An apparatus according to the present invention is an image forming apparatus that forms an image by an electrophotographic method, and is a consumable member that is replaceably mounted in the apparatus main body, and a conveying member that conveys waste toner discharged from the consumable member And a waste toner box for receiving and storing waste toner transported by the transport member, and a control unit for controlling the consumable member and the transport member. When it is detected that the driving time has been reached, control is performed so that the driving time of the conveying member becomes longer than the driving time in a normal image forming operation.

  According to the present invention, waste toner can be prevented from spilling when a consumable member or the like is replaced with a simple configuration without shortening the lifetime of the consumable member and other devices constituting the image forming apparatus.

  FIG. 1 is a sectional front view showing a schematic configuration of an image forming apparatus 1 according to an embodiment of the present invention, FIG. 2 is a diagram showing a configuration of an imaging unit U, FIG. 3 is a perspective view of the imaging unit U, and FIG. FIG. 5 is a cross-sectional view showing the structure of the discharge portion of the shutter of the toner transport screw 31 of the imaging unit U, FIG. 6 is a diagram showing the operation of the shutter of the toner transport screw 31, and FIG. 2 is a block diagram illustrating a configuration of a control system 3 of the forming apparatus 1. FIG.

  In FIG. 1, an image forming apparatus 1 is a digital multi-function peripheral or printer using an electrophotographic system, and has a built-in tandem print engine.

  That is, the image output apparatus 1 includes Y (yellow), M (magenta), C (cyan), and K (black) imaging units UY, UM, UC, UK arranged in a row in a tandem format. Yes.

  Referring also to FIGS. 2 to 4, each of the imaging units UY, UM, UC, UK has a photosensitive drum 11, a charging charger 12 for uniformly charging the surface of the photosensitive drum 11, and an electrostatic latent image, respectively. The developing unit 13 that develops with each color toner to form a toner image, the cleaner 15 that scrapes and cleans the toner remaining on the surface of the photosensitive drum 11, and the imaging unit U that uses the scraped toner as waste toner. A toner conveying screw (toner collecting screw) 31 to be discharged to the outside is included.

  The photosensitive drum 11 is exposed by a laser beam modulated in accordance with image data of each color by an exposure unit 14 provided outside the imaging unit U, and forms an electrostatic latent image on the surface thereof. Further, the toner image formed by the development is transferred to the intermediate transfer belt 18 by the operation of the transfer roller 22 provided at a position facing the photosensitive drum 11.

  In the present specification and drawings, the symbols corresponding to the colors Y, M, C, and K may be suffixed with the symbols Y, M, C, and K, respectively.

  The document image is read by the scanner 21 and necessary processing is performed on the obtained image data, and the laser light of the exposure unit 14 is modulated by the image data. Thus, after each color toner image is formed in each imaging unit U, the toner image is primarily transferred to the intermediate transfer belt 18. The intermediate transfer belt 18 is stretched between two rollers on both sides so as to be along the upper portions of the photosensitive drums 11Y, 11M, 11C, and 11K, and travels by the rotation of the rollers.

  The toner image primarily transferred to the intermediate transfer belt 18 is secondarily transferred onto the recording paper fed from the paper feed cassette 22 by the secondary transfer roller 19. Thereafter, the recording paper is fixed by the fixing unit 23 and discharged to the paper discharge tray 24.

  In addition, in the vicinity of one roller that rotatably supports the intermediate transfer belt 18, a belt cleaner (not shown) that scrapes off toner remaining on the intermediate transfer belt 18, and toner scraped off by the belt cleaner to the outside as waste toner. A toner conveying screw 33 for discharging is provided.

  As can be seen from the above description, each color imaging unit U is unitized, and can be easily attached to and removed from each mounting location in the apparatus main body 10 for each color, making replacement and maintenance easy. is there. That is, in the image forming apparatus 1, the imaging unit U is a consumable member (consumable item), and is replaced with a new one when its life is shortened by use.

  Each imaging unit U is provided with a motor for rotationally driving the photosensitive drum 11, the developing unit 13, the toner conveying screw 31, and the like, and each imaging unit U operates independently. It is possible.

  The intermediate transfer belt 18 is unitized as a transfer belt unit TU together with a roller for rotating the belt, a belt cleaner, a toner conveying screw 33, and the like. Therefore, the transfer belt unit TU can also be easily attached to and removed from the apparatus main body 10 and can be easily replaced and maintained. That is, the transfer belt unit TU is also one of the consumable members (consumables), and is replaced with a new one when the life is reached by use. The transfer belt unit TU is provided with a motor for rotationally driving the roller, the toner conveying screw 33, and the like, and can operate independently of other members.

  As shown well in FIG. 4, the apparatus main body 10 includes a second conveying screw (second recovery screw) 32 as a conveying member so as to cross the lower side of each toner conveying screw 31 provided in the imaging unit U. Is provided. The second conveying screw 32 is provided with a motor for rotationally driving it, and can operate independently.

  A waste toner box 34 for receiving and storing waste toner transported by the second transport screw 32 and the toner transport screw 33 is provided below the ends of the second transport screw 32 and the toner transport screw 33.

  The waste toner box 34 has a long shape along the same direction as the longitudinal direction of the imaging unit U, and waste toner inlets 34a and 34b are provided in the vicinity of both ends thereof. The waste toner conveyed by the second conveyance screw 32 falls from the end of the second conveyance screw 32 and enters the inlet 34 a, and the waste toner conveyed by the toner conveyance screw 33 becomes the end of the toner conveyance screw 33. Falls from the section and enters the inlet 34b. Although not shown in the drawing, a cylindrical guide is provided between each end of the second conveying screw 32 and the toner conveying screw 33 and the inlets 34a and 34b so that the waste toner is not scattered outside. It has been.

  When the imaging unit U is pulled out from the apparatus main body 10, the connection between the toner conveying screw 31 and the second conveying screw 32 is disconnected. When the transfer belt unit TU is pulled out from the apparatus main body 10, the connection between the toner conveying screw 33 and the waste toner box 34 is disconnected.

  Although not shown, the waste toner box 34 is provided with a waste toner full sensor 35 (see FIG. 7) for detecting that the waste toner stored therein is full.

  In FIG. 5, the toner conveying screw 31 is provided with a rotating screw 312 rotatably in a casing 311 having a U-shaped cross section. An outlet 313 is provided at the end of the casing 311, and waste toner dropped from the outlet 313 is received by the coupling portion 322 of the second conveying screw 32 below the outlet 313. A shutter mechanism 314 capable of opening and closing the outlet 313 is provided at the end of the casing 311.

  The shutter mechanism 314 includes an opening / closing cover 315 that is slidable in the axial direction along the outer periphery of the casing 311, opens and closes the outlet 313, and a spring 316 that biases the opening / closing cover 315 in the closing direction. The opening / closing cover 315 always closes the outlet 313 by a spring 316, and an engagement member (not shown) provided on the apparatus main body 10 side when the imaging unit U is mounted at a predetermined regular position. Engages with the opening / closing cover 315 and slides it to open the outlet 313.

  The shutter mechanism 314 prevents waste toner remaining in the toner conveying screw 31 from spilling outside when the imaging unit U is pulled out of the apparatus main body 10 for replacement or the like. However, as described above, the waste toner accumulated near the outlet 313 may be spilled as it is.

  That is, as shown in FIG. 6A, when the imaging unit U is mounted at the regular position, all of the waste toner TN that has exited from the outlet 313 enters the coupling portion 322 of the second conveying screw 32 and is removed from the outside. 6B, when the imaging unit U starts to be pulled out, the outlet 313 is displaced from the position of the coupling portion 322, and the shutter mechanism 314 is not completely closed yet. All of the toner TN does not enter the coupling part 322, and a part of the toner TN spills out.

  As shown in FIG. 6C, when the imaging unit U is pulled out, the shutter mechanism 314 completely blocks the outlet 313, and the waste toner TN does not spill thereafter.

  In the present embodiment, the waste toner TN is prevented from spilling from the toner conveying screw 31 to the outside even when the imaging unit U is pulled out from the apparatus main body 10 to be in the state shown in FIG.

  In FIG. 7, the control system 3 of the image forming apparatus 1 includes an engine control unit 101 that controls image forming means such as the imaging unit U, and a controller control unit 102 that controls the engine control unit 101. The engine control unit 101 and the controller control unit 102 are connected by a communication interface 103 to perform communication.

  The engine control unit 101 is connected to and controlled by various motors that are driving sources in the image forming apparatus 1. Examples of the motors include four motors (U motors) M1 of the imaging units U of the respective colors, a motor (transfer belt motor) M3 of the transfer belt unit TU, and a motor (U second motor) for the second conveying screw 32. ) There are M2 and other motors.

  In addition, a waste toner full sensor 35 is connected to the engine control unit 101, and a waste toner full detection signal S1 output from the waste toner full sensor 35 is received and a waste toner full determination is performed.

  That is, the engine control unit 101 includes a U life determination unit 111, a transfer belt life determination unit 112, and a waste toner full determination unit 113. The U life determination unit 111 determines whether the imaging unit U has reached the end of its life. The transfer belt life determination unit 112 determines whether the transfer belt unit TU has reached the end of its life. The waste toner full determination unit 113 determines whether the waste toner box 34 is in a waste toner full state, that is, full.

  Consumable members such as the imaging unit U and the transfer belt unit TU are managed based on lifetime management information such as the number of lifetimes and lifetime stored in a nonvolatile memory (for example, EEPROM) provided in the control system 3. . Whether or not these consumable members have reached the end of their life (life determination) is determined by comparing their life management information with counter values such as the actual operation time of the consumable members and the actual number of printed sheets of the image forming apparatus 1. If it is determined that the lifetime has been reached, the engine control unit 101 notifies the controller control unit 102 to that effect.

  When the controller control unit 102 receives a notification that it has reached the end of its life, the controller control unit 102 enters a disposal conveyance mode, and performs disposal conveyance control for discharging the waste toner TN in the consumable member to the outside. In the waste transport control, the drive time of the toner transport screw 31, the second transport screw 32, or the toner transport screw 33 for transporting the waste toner TN at the end of image formation is set to be longer than the drive time in the normal image forming mode. Control to be longer. At the same time, a message prompting the user to replace the corresponding consumable member is displayed on the display surface of an operation panel (not shown) provided in the image forming apparatus 1.

  When the waste toner full determination unit 113 determines that the waste toner is full, the controller control unit 102 is notified of this. As a result, the controller control unit 102 performs waste transport control in the same manner as above, and displays a message prompting the user to replace the waste toner box 34 on the display surface of the operation panel.

  Since the full waste toner box 34 is discarded and replaced with a new one, it can be said that the waste toner box 34 is a consumable member. Also in this specification, the waste toner box 34 can be handled as a consumable member.

  Next, the discard conveyance control will be described. The contents of the discard conveyance control differ depending on the consumable member whose cause is detected.

  FIG. 8 is a timing chart showing the operation of each motor at the end of the image forming operation.

  FIG. 8A shows the operation at the end of the normal image formation mode (normal image formation end control). That is, when the image formation is completed, all of the U motor M1, the transfer belt motor M3, and the U second motor M2 are simultaneously stopped at time t1.

  FIG. 8B shows waste transport control based on the lifetime of the imaging unit U. When the image formation is completed, the transfer belt motor M3 is stopped according to the normal sequence at time t1, but the U motor M1 and the U second motor M2 of the imaging unit U determined to have a lifetime are at time t1. Extend the drive time without stopping.

  That is, the transfer belt motor M3 is stopped at time t1, the U motor M1 is stopped at time t2 when the time T1 has passed, and the U second motor M2 is stopped when time T2 has passed from the time t2. As a result, the driving time is extended by the time T1 for the U motor M1 and the time (T1 + T2) for the U second motor M2. The time T1 is about 2 seconds, for example, and the time T2 is about 1.3 seconds, for example.

  Therefore, the waste toner TN remaining in each toner conveying screw 31 or the second conveying screw 32 is conveyed and discharged to the outside while being driven by the extension, and the toner conveying screw 31 and the second conveying screw 32 The waste toner TN does not remain inside.

  Therefore, after that, when the corresponding imaging unit U is pulled out from the apparatus main body 10 for replacement, the waste toner TN does not remain inside, and therefore, the waste toner TN does not spill.

  FIG. 8C shows waste conveyance control based on the life of the transfer belt unit TU. When the image formation is completed, the U motor M1 and the U second motor M2 are stopped at the time t1, but the driving time is extended without stopping the transfer belt motor M3.

  That is, at time t1, the U motor M1 and the U second motor M2 are stopped, and the transfer belt motor M3 is stopped when time T3 has elapsed from time t1. As a result, the driving time of the transfer belt motor M3 is extended by the time T3. The time T3 is about 3 seconds, for example.

  Accordingly, the waste toner TN remaining on the toner transport screw 33 is transported and stored in the waste toner box 34 while being driven by the extension, and no waste toner TN remains in the toner transport screw 33. Become.

  Accordingly, after that, when the transfer belt unit TU is pulled out from the apparatus main body 10 for replacement, the waste toner TN does not remain in the interior, and therefore, the waste toner TN does not spill.

  FIG. 8D shows waste conveyance control when the waste toner box 34 becomes full of waste toner. When the image formation is completed, the U motor M1 stops at time t1, but the driving time is extended without stopping the U second motor M2 and the transfer belt motor M3.

  That is, the U motor M1 is stopped at the time t1, and the U second motor M2 or the transfer belt motor M3 is stopped when the time T4 or the time T5 has elapsed from the time t1. As a result, the driving time of the transfer belt motor M3 is extended by the time T3. The time T3 is about 3 seconds, for example.

  Accordingly, the waste toner TN remaining on the toner transport screw 33 is transported and stored in the waste toner box 34 while being driven by the extension, and no waste toner TN remains in the toner transport screw 33. Become.

  Therefore, after that, when the transfer belt unit TU is pulled out from the apparatus main body 10 for replacement, the waste toner TN does not remain in the interior, so that the waste toner TN does not spill.

  The times T1 to T5 may be set to the minimum time necessary for discharging the remaining waste toner TN to the outside.

  Next, the discard conveyance control will be described with reference to a flowchart.

  9 is a flowchart showing a main routine in image formation, FIG. 10 is a flowchart showing waste transport control based on the life of the imaging unit U, FIG. 11 is a flowchart showing waste transport control based on the life of the transfer belt unit TU, and FIG. 10 is a flowchart showing waste transport control when the box becomes full of waste toner.

  In FIG. 9, the engine control unit 101 manages the life determination counter information for the imaging units U of each color of YMCK and the transfer belt unit TU. During printing operation (image formation) (# 12), if any counter exceeds the threshold for determining the life or toner full is detected, after the printing operation is finished (# 13), the waste transport to the corresponding consumable member Control (# 15, 17, 19) is performed.

  In FIG. 10, for the imaging unit U whose life has been detected, the U toner M1 is rotationally driven by the U motor M1 to discharge the remaining waste toner TN (# 21). When the discharge is completed after a predetermined time has elapsed (# 22), the U motor M1 is stopped (# 23). The second waste screw TN is discharged by rotating the second conveying screw 32 by the U second motor M2 (# 24). When the discharge is completed after a predetermined time has elapsed (# 25), the U second motor M2 is stopped (# 26).

  In FIG. 11, the transfer belt motor M3 rotates the toner conveying screw 33 to discharge the remaining waste toner TN (# 31). When the discharge is finished after a predetermined time has elapsed (# 32), the transfer belt motor M3 is stopped (# 33).

  In FIG. 12, the second conveying screw 32 is rotationally driven by the U second motor M2, and the toner conveying screw 33 is rotationally driven by the transfer belt motor M3, and the remaining waste toner TN is discharged (# 41). When the discharge is finished (# 42), the finished U second motor M2 or transfer belt motor M3 is stopped (# 43), and when all the waste toner TN is discharged, all the motors are stopped and finished (#). 44).

  According to the image forming apparatus 1 of the above-described embodiment, when the life or full state of the consumable member is detected, the corresponding toner conveying screw 31 and second conveying screw 32 after the normal image forming sequence ends. Alternatively, the toner conveying screw 33 is extended and rotated to discharge the remaining waste toner TN to the outside. As a result, the waste toner TN does not remain inside the imaging unit U or the transfer belt unit TU that has reached the end of life, or the second conveyance screw 32 or the toner conveyance screw 33 that feeds the waste toner TN to the waste toner box 34. The waste toner TN is not spilled when they are exchanged.

  As described above, according to this embodiment, the life of consumable members and other devices constituting the image forming apparatus 1 is not shortened, and waste toner is spilled when the consumable members are replaced with a simple configuration. Can be prevented.

  Further, when the waste toner box 34 is removed for replacement, even if the user forgets to install a new waste toner box 34 and the image forming apparatus 1 is turned on and started up, the second conveying screw 32 is then turned on. In addition, since the waste toner TN is not accumulated in the toner conveying screw 33, the waste toner TN is not spilled.

  Further, since the shutter mechanism 314 in the toner conveying screw 31 can be omitted, the structure of the toner conveying screw 31 is simplified accordingly, leading to cost reduction.

  Furthermore, since driving is performed using the optimum means and time according to the consumable member whose life has been detected, the influence on the waiting time and the life of other consumable members can be suppressed.

  In the above-described embodiment, the individual U motors M1 are provided for the imaging units U of the respective colors. However, the imaging units U of the respective colors can be driven in conjunction with each other using the common U motor M1. However, in that case, waste conveyance control is performed not only in the imaging unit U that has reached the end of life but also in all the imaging units U, and the toner conveyance screw 31 operates for an extended period of time. There is sex. However, since the waste conveyance control is performed only when the lifetime is reached, the lifetime is not greatly affected by limiting the time required to remove the waste toner TN.

  In the above embodiment, the toner conveying screw 31, the second conveying screw 32, the toner conveying screw 33, the waste toner box 34, the imaging unit U, the transfer belt unit TU, or the structure or shape of the whole or each part of the image forming apparatus 1, The arrangement, material, number, contents of control, and the like can be variously changed in addition to those described above.

1 is a cross-sectional front view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the structure of an imaging unit. It is a perspective view of an imaging unit. It is a perspective view showing a toner conveyance mechanism. FIG. 6 is a cross-sectional view illustrating a structure of a discharge portion of a shutter of a toner conveying screw. FIG. 6 is a diagram illustrating an operation of a shutter of a toner conveying screw. 2 is a block diagram illustrating a configuration of a control system of the image forming apparatus. FIG. FIG. 6 is a timing chart showing the operation of each motor at the end of the image forming operation. 3 is a flowchart showing a main routine in image formation. It is a flowchart of the waste conveyance control by the lifetime of an imaging unit. It is a flowchart of waste conveyance control by the life of a transfer belt unit. 10 is a flowchart of waste transport control when the waste toner is full.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Control system (control part)
10 Device Body 11 Photosensitive Drum (Photoconductor)
13 Development section (developing device)
31 Toner conveying screw (conveying screw, toner recovery screw)
32 Second conveying screw (conveying member, conveying screw)
33 Toner conveying screw (conveying screw)
34 Waste toner box (consumable member)
101 Engine control unit (control unit)
102 Controller control unit (control unit)
U Imaging unit (consumable member)
TU transfer belt unit (consumable member)
TN waste toner

Claims (6)

A waste toner conveyance control method in an image forming apparatus for forming an image by an electrophotographic method,
When it is detected that the consumable member that is replaceably mounted in the apparatus main body has reached the end of its life, the driving time of the conveying screw for conveying the waste toner becomes longer than the driving time in the normal image forming operation. The waste toner remaining in the conveying screw is discharged to the outside.
A waste toner conveyance control method in an image forming apparatus. An image forming apparatus for forming an image by electrophotography,
A consumable member that is replaceably mounted in the apparatus body;
A transport member for transporting waste toner discharged from the consumable member;
A waste toner box for receiving and storing waste toner conveyed by the conveying member;
A controller that controls the consumable member and the transport member,
The control unit performs control so that when the consumable member has reached the end of its life, the driving time of the transport member is longer than the driving time in a normal image forming operation.
An image forming apparatus. The consumable member is an imaging unit including a photoreceptor, a developing device, and a toner collecting screw for conveying waste toner generated inside to the outside,
The controller extends the drive time of the toner recovery screw when it is detected that the imaging unit has reached the end of its life, and further, the transport member is driven after the drive of the toner recovery screw is completed. So as to extend the driving time of the conveying member,
The image forming apparatus according to claim 2. The imaging unit is provided for each of the colors Y, M, C, and K, and whether or not the lifetime of each color imaging unit has been reached is detected.
The control unit extends the driving time of the toner recovery screw for the color imaging unit detected to have reached the end of its life,
The image forming apparatus according to claim 3. The consumable member is a transfer belt unit including a transfer belt and a toner conveying screw for conveying waste toner generated from the transfer belt to the outside.
The controller extends the driving time of the toner conveying screw when it is detected that the transfer belt unit has reached the end of its life.
The image forming apparatus according to claim 2. The controller extends the drive time of the transport member and the toner transport screw when it is detected that the waste toner box is full.
The image forming apparatus according to claim 2.

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