Patent Publication Number: US-8116644-B2

Title: Image forming apparatus and waste powder transporting method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC §119 from Japanese Patent Application No. 2008-249039 filed Sep. 26, 2008. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to an image forming apparatus and a waste powder transporting method. 
     2. Related Art 
     Some image forming apparatuses are provided with a recovery device that recovers, as a waste toner, a toner that has not been used for image formation. 
     SUMMARY 
     According to an aspect of the present invention, there is provided an image forming apparatus including: an image forming section that forms an image on a recording medium; a storage container that is detachably and attachably provided and that stores waste powder having been discarded and transported from the image forming section; a first transporting section that transports, from the image forming section, the waste powder having been discarded in the image forming section; a transport path through which the waste powder having been transported by the first transporting section is caused to fall down and is transported; a second transporting section that transports, to the storage container, the waste powder having been transported through the transport path; and a controller that stops driving of the second transporting section if an operation set in advance is executed when the storage container is removed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiment(s) of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  is a diagram showing a configuration of a digital color printer as an example of an image forming apparatus; 
         FIG. 2  is a diagram showing the transporting mechanism from the rear side of the image forming apparatus; 
         FIG. 3  is a diagram showing a reciprocation mechanism that causes the coil spring to reciprocate; 
         FIG. 4  is an enlarged diagram showing the fourth transporting mechanism and the fifth transporting mechanism; 
         FIG. 5  is a diagram showing the control block of the controller; 
         FIG. 6  is a diagram showing an operation sequence of the first to the fifth motors provided respectively to the first to the fifth transporting mechanisms as well as the sixth motor that rotationally drives the photoconductor drums; 
         FIG. 7  is a diagram showing a return sequence of the transporting mechanism and the like; and 
         FIG. 8  is a diagram showing another example of the operation sequence of the first to the sixth motors. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 
       FIG. 1  is a diagram showing a configuration of a digital color printer as an example of an image forming apparatus to which the exemplary embodiment is applied. 
     The image forming apparatus  1  of the present exemplary embodiment includes a sheet feeding unit  1 A, an image formation unit  1 B, and a sheet outputting unit  1 C. 
     The sheet feeding unit  1 A includes a first sheet storage part  11  to a fourth sheet storage part  14 , each of which stores paper sheets serving as an example of a recording medium. The sheet feeding unit  1 A further includes sending rolls  15  to  18  provided respectively for the first to fourth sheet storage parts  11  to  14 . The sending rolls  15  to  18  send paper sheets stored in the respective sheet storage parts  11  to  14  to transport paths each connected to the image formation unit  1 B. 
     The image formation unit  1 B is of a so-called tandem type, and includes an image forming process part  20 , a controller  21 , and an image processing part  22 . The image forming process part  20  forms an image on a paper sheet on the basis of image data of each color. The controller  21  controls the image forming process part  20  and the like. The image processing part  22  is connected, for example, to an image reading apparatus  4  and a personal computer (PC)  5 , and performs image processing on image data received from these devices. 
     The image forming process part  20 , as an example of an image forming section, includes six image forming units  30 T,  30 P,  30 Y,  30 M,  30 C, and  30 K (hereinafter, sometimes referred to simply as “image forming units  30 ”) arranged in parallel at intervals. Each image forming unit  30  includes a photoconductor drum  31 , a charging roll  32 , a developing device  33 , and a cleaning unit  34 . An electrostatic latent image is formed on the photoconductor drum  31  while the photoconductor drum  31  is rotating in a direction indicated by an arrow A in the figure. The charging roll  32  electrically charges a surface of the photoconductor drum  31  uniformly. The developing device  33  develops the electrostatic latent image formed on the photoconductor drum  31 . The cleaning unit  34  removes an untransferred toner and the like on the surface of the photoconductor drum  31 . In addition, the image forming process part  20  is provided with a laser exposure device  26  that scans and exposes, with a laser beam, the photoconductor drums  31  of the respective image forming units  30 T,  30 P,  30 Y,  30 M,  30 C, and  30 K. Moreover, the image forming process part  20  includes a motor (not shown in the figure) to rotationally drive the respective photoconductor drums  31  of the image forming units  30 T,  30 P,  30 Y,  30 M,  30 C, and  30 K. Note that, in the specification, the motor to rotationally drive the respective photoconductor drums  31  is referred to as a sixth motor M 6  for the convenience of description. 
     Here, all the image forming units  30  have almost the same configuration except for the toner stored in the respective developing devices  33 . Yellow (Y), magenta (M), cyan (C), and black (K) toner images are formed in the image forming units  30 Y,  30 M,  30 C, and  30 K, respectively. 
     Meanwhile, in addition to the commonly-used four colors (normal colors), that is, yellow, magenta, cyan, and black, another image forming material is sometimes desired to be used in the forming of an image on a paper sheet. Specifically, there is a case where an image is desired to be formed on a paper sheet by using an image forming material, such as a spot color, that is difficult or impossible to be expressed with the commonly-used four colors. For example, an image is sometimes desired to be formed on a paper sheet by using a toner, such as a toner of a corporate color dedicated to a specific user, a foam toner for Braille, a fluorescent toner, a toner that improves a gloss, a ferromagnetic toner, an invisible toner having sensitivity to the infrared region, or the like. For this reason, the image formation unit  1 B of the present exemplary embodiment is provided with image forming units  30 T and  30 P that achieve image formation using a spot color and the like, in addition to the generally-mounted image forming units  30 Y,  30 M,  30 C, and  30 K. 
     Moreover, the image forming process part  20  includes the intermediate transfer belt  41 , primary transfer rolls  42 , a secondary transfer roll  40 , a belt cleaner  45 , and a fixing device  80 . Onto the intermediate transfer belt  41 , various color toner images formed by the photoconductor drums  31  of the respective image forming units  30  are superimposedly transferred. The primary transfer rolls  42  sequentially transfer (primarily transfer) the various color toner images of the respective image forming units  30  onto the intermediate transfer belt  41  at a primary transfer portion T 1 . The secondary transfer roll  40  transfers (secondarily transfers) the superimposed toner images, which have been transferred onto the intermediate transfer belt  41 , together onto a paper sheet at a secondary transfer portion T 2 . The belt cleaner  45  removes an untransferred toner and the like on the surface of the intermediate transfer belt  41 . The fixing device  80  fixes a secondarily transferred image onto the paper sheet. 
     The image forming process part  20  performs an image forming operation on the basis of control signals sent from the controller  21 . First, image data inputted through the image reading apparatus  4  or the PC  5  are subjected to image processing by the image processing part  22 , and then supplied to the laser exposure device  26 . Then, for example, in the magenta (M) image forming unit  30 M, after the surface of the photoconductor drum  31  is uniformly charged with a potential set in advance, by the charging roll  32 , the photoconductor drum  31  is scanned and exposed by the laser exposure device  26  with a laser beam modulated according to the image data acquired from the image processing part  22 . In this way, an electrostatic latent image is formed on the photoconductor drum  31 . The electrostatic latent image thus formed is developed by the developing device  33 , so that a magenta toner image is formed on the photoconductor drum  31 . In the same manner, yellow, cyan, and black toner images are formed respectively in the image forming units  30 Y,  30 C, and  30 K, and also, toner images of spot colors or the like are formed respectively in the image forming units  30 T and  30 P. 
     These color toner images having been formed in the respective image forming units  30  are electrostatically transferred (primarily transferred) in sequence by the corresponding primary transfer rolls  42  onto the intermediate transfer belt  41  rotating in a direction indicated by an arrow C in  FIG. 1 , so that superimposed toner images are formed on the intermediate transfer belt  41 . 
     On the other hand, the untransferred toner and the like remaining on each photoconductor drum  31  at the primary transfer are removed (discarded) by the cleaning unit  34  disposed downstream of the primary transfer roll  42 . Each cleaning unit  34  includes a transporting member  341  provided along an axial direction of the photoconductor drum  31 . The transporting member  341  transports the removed untransferred toner and the like to a rear side (back part side) of the image formation unit  1 B. The untransferred toner and the like (a waste powder) transported by the transporting member  341  to the rear side of the image formation unit  1 B are then transported by a transporting mechanism  100  to a first storing container  210  or a second storing container  220 . Here, the transporting mechanism  100  is provided also in the rear side of the image formation unit  1 B, while the first and second storing containers  210  and  220  are both detachably and attachably provided in the sheet outputting unit  1 C. 
     Here, in the present exemplary embodiment, two storing containers are provided. Specifically, the two storing containers are the first storing container  210  and the second storing container  220 . Accordingly, for example, even if any one of the storing containers is filled up, this configuration allows an image forming operation to be continuously performed by transporting the untransferred toner and the like to the other one of the storing containers. Moreover, for example, this configuration also allows a reduction in weight of the storing container that contains the untransferred toner and the like therein when the storing container is detached, as compared with a configuration in which the untransferred toner and the like are stored in a single storing container having a large capacity. 
     In addition, in the present exemplary embodiment, a first sensor S 1  and a second sensor S 2  are provided. The first sensor S 1  performs detection on the first storing container  210 , while the second sensor S 2  performs detection on the second storing container  220 . A third sensor S 3 , which outputs a signal set in advance when the untransferred toner and the like reach an upper portion of the first storing container  210  (when the first storing container  210  is filled up with the untransferred toner and the like), is also provided. Further, a fourth sensor S 4 , which outputs a signal set in advance when the untransferred toner and the like reach an upper portion of the second storing container  220  (when the second storing container  220  is filled up with the untransferred toner and the like), is provided. Furthermore, in the present exemplary embodiment, a temperature sensor S 5  and a humidity sensor S 6  are provided. The temperature sensor S 5  measures the inside temperature of the image forming apparatus  1 , while the humidity sensor S 6  measures the inside humidity of the image forming apparatus  1 . Note that, although the first storing container  210  and the second storing container  220  are provided in the sheet outputting unit  1 C in the present exemplary embodiment, these storing containers may be provided alternatively in the image formation unit  1 B. 
     On the other hand, the superimposed toner images formed on the intermediate transfer belt  41  are transferred, according to the movement of the intermediate transfer belt  41 , toward the secondary transfer portion T 2  in which the secondary transfer roll  40  and a backup roll  49  are disposed. Meanwhile, the paper sheet is transferred to a position of a registration roll  74  after being taken out of, for example, the first sheet storage part  11  by the sending roll  15  and then passing through the transport path. 
     At the timing when the superimposed toner images are transported to the secondary transfer portion T 2 , the paper sheet is fed to the secondary transfer portion T 2  from the registration roll  74 . Then, the superimposed toner images are electrostatically transferred (secondarily transferred) together onto the paper sheet by the action of a transfer electric field formed between the secondary transfer roll  40  and the backup roll  49  at the secondary transfer portion T 2 . 
     Thereafter, the paper sheet having the superimposed toner images electrostatically transferred thereon is peeled from the intermediate transfer belt  41 , and then, is transported to the fixing device  80 . The unfixed toner images on the paper sheet having been transported to the fixing device  80  are subjected to a fixing process with heat and pressure by the fixing device  80  so as to be fixed onto the paper sheet. Then, the paper sheet having a fixed image formed thereon passes through a curl correcting part  81  provided in the sheet outputting unit  1 C, and then, is transported to an outputted-sheet stacking unit (not shown in the figure). 
     On the other hand, the untransferred toner and the like remaining on the surface of the intermediate transfer belt  41  after the secondary transfer are removed (discarded) by the belt cleaner  45 , which is disposed in contact with the intermediate transfer belt  41 , after the completion of the secondary transfer. The belt cleaner  45  includes a transporting member  451  that is provided to extend from the front side to the rear side of the image formation unit  1 B, and that transports the untransferred toner and the like thus removed to the rear side of the image formation unit  1 B. Then, the untransferred toner and the like (waste powder) transported to the rear side of the image formation unit  1 B by the transporting member  451  are transported to the first storing container  210  or the second storing container  220  by the transporting mechanism  100 . Note that, in the specification, the untransferred toner and the like transported from the cleaning unit  34  and the belt cleaner  45  to the transporting mechanism  100  are hereinafter referred to as a waste toner. 
     Subsequently, the transporting mechanism  100  will be described in detail. 
       FIG. 2  is a diagram showing the transporting mechanism  100  from the rear side of the image forming apparatus  1 . 
     As shown in  FIG. 2 , the transporting mechanism  100  includes first transporting mechanisms  110  that are provided corresponding to the respective image forming units  30 , and that transport the waste toner from the cleaning units  34 . In addition, the transporting mechanism  100  includes a discharging part  170  to which the waste toner from the belt cleaner  45  is discharged. Moreover, the transporting mechanism  100  includes a second transporting mechanism  120 , a third transporting mechanism  130 , a fourth transporting mechanism  140 , and a fifth transporting mechanism  150 . The second transporting mechanism  120  transports the waste toner having been transported by the first transporting mechanisms  110  and the waste toner having been discharged from the discharging part  170 . The third transporting mechanism  130  transports the waste toner having been transported by the second transporting mechanism  120 . The fourth transporting mechanism  140  transports the waste toner having been transported by the third transporting mechanism  130 , and the fifth transporting mechanism  150  transports, to the first storing container  210  or the second storing container  220 , the waste toner having been transported by the fourth transporting mechanism  140 . 
     Note that the transporting member  341  (see  FIG. 1 ), the first transporting mechanisms  110  and the second transporting mechanism  120  in the present exemplary embodiment may be taken as a first transporting section that transports the waste toner (waste powder) from the image forming process part  20  functioning as an image forming section. The fourth transporting mechanism  140  and the fifth transporting mechanism  150  in the present exemplary embodiment may be taken as a second transporting section that transports, to the first storing container  210  and the like, the waste toner transported via the transport path, which is formed by the tubular member  131  (which will be described later). 
     Each of the first transporting mechanisms  110  includes a tubular member  111 , a coil spring  112 , and a first motor M 1 . The tubular member  111  forms a transport path for the waste toner having been transported by the transporting member  341  (see  FIG. 1 ) provided to the cleaning unit  34 . The coil spring  112 , which is an example of a breaking member, is provided inside the tubular member  111  and breaks down the waste toner adhering to an inner wall surface of the tubular member  111  by reciprocating along the tubular member  111 . The first motor M 1  rotationally drives the transporting member  341  and causes the coil spring  112  to reciprocate. 
     Each tubular member  111  is provided to extend in the up and down direction (the approximately vertical direction). Accordingly, the waste toner having been transported by the transporting member  341  falls down (free-falls) inside this tubular member  111 . 
     Each coil spring  112  is formed of a wire, and has a helical (coil) shape. Specifically, each coil spring  112  does not have a rotational shaft unlike a transporting member  142  (see  FIG. 4 ) having a rotational shaft  142 A, which will be described later and has a shape allowing the waste toner to pass through the center portion thereof. In other words, the shape of each coil spring  112  allows the waste toner to fall down in the tubular member  111 . Each coil spring  112  is caused to reciprocate inside the tubular member  111  by the first motor M 1  so as to break down the waste toner having been agglomerated inside the tubular member  111  or to remove the waste toner from the inner wall of the tubular member  111 . 
     The second transporting mechanism  120  includes a tubular member  121 . The tubular member  121  is disposed to extend in an arrangement direction of the image forming units  30 T,  30 P,  30 Y,  30 M,  30 C, and  30 K (in the horizontal direction, approximately), is connected to the tubular members  111  and the discharging part  170 , and forms a transport path for the waste toner. In addition, the second transporting mechanism  120  further includes the transporting member  122  and a second motor M 2 . The transporting member  122  is disposed inside the tubular member  121 , and transports the waste toner having been transported from the first transporting mechanisms  110  and the waste toner having been discharged from the discharging part  170 . The second motor M 2  rotationally drives the transporting member  122 . Incidentally, the transporting member  122  is configured similarly to the transporting member  142  and the transporting member  152  (see  FIG. 4 ), both of which will be described later. 
     The transporting member  341  (see  FIG. 1 ) in the present exemplary embodiment may be taken as an upstream-side transporting mechanism that transports the waste toner (waste powder) from the image forming process part  20  functioning as an image forming section. The transport path of the waste toner formed by the tubular member  111  may be taken as a falling-down transport path through which the waste powder falls down so as to be transported. Moreover, the second transporting mechanism  120  may be taken as a downstream-side transporting mechanism that transports the waste toner having been transported through the falling-down transport path to the transport path of the waste toner formed by the tubular member  131 . 
     The third transporting mechanism  130  includes a tubular member  131  that is provided to extend in the up and down direction (the approximately vertical direction), that is connected to the tubular member  121 , and that forms a transport path for the waste toner. In addition, the third transporting mechanism  130  includes a coil spring  132  and a third motor M 3 . The coil spring  132  is provided inside the tubular member  131 , and is reciprocatable along the tubular member  131 . The third motor M 3  causes the coil spring  132  to reciprocate. 
     The tubular member  131  is provided to extend in the up and down direction (the approximately vertical direction). Accordingly, the waste toner having been transported by the second transporting mechanism  120  falls down (free-falls) inside this tubular member  131 . 
     The coil spring  132  is formed of a wire, and also has a helical (coil) shape, as in the case of the coil spring  112 . In addition, the coil spring  132  does not have a rotational shaft, and has a shape allowing the waste toner to pass through the center portion thereof, as in the above-described case. In other words, the shape of the coil spring  132  allows the waste toner to fall down in the tubular member  131 . The coil spring  132  is caused to reciprocate inside the tubular member  131  by the third motor M 3  so as to break down the waste toner having been agglomerated inside the tubular member  131  or to remove the waste toner from the inner wall of the tubular member  131 . 
     Note that, the reciprocation of the coil spring  132  is achieved by, for example, a configuration shown in  FIG. 3 . 
     Here,  FIG. 3  is a diagram showing a reciprocation mechanism that causes the coil spring  132  to reciprocate. As shown in  FIG. 3 , the third transporting mechanism  130  includes a rotating member  133  and a driving member  134 . The rotating member  133  is rotated by the third motor M 3  (see  FIG. 2 ). One end portion of the driving member  134  is attached to the rotating member  133 , while an upper end portion of the coil spring  132  is attached to the driving member  134 . The driving member  134  is formed in a crank shape. In addition, the driving member  134  is configured so that an attachment portion thereof to which the coil spring  132  is attached passes a position eccentric to the center of the axis of the rotating member  133  when the third motor M 3  is driven. Accordingly, once the third motor M 3  is started to be driven, the coil spring  132  is caused to reciprocate along the tubular member  131  (see an arrow D) by the driving member  134 . Note that, although a description has been omitted above, each of the coil springs  112  in the first transporting mechanisms  110  (see  FIG. 2 ) is also caused to reciprocate by the same mechanism as that shown in  FIG. 3 . 
     Referring back to  FIG. 2  again, the transporting mechanism  100  will be further described. 
     The fourth transporting mechanism  140  includes a tubular member  141  that forms a transport path for the waste toner. The tubular member  141  is disposed to intersect (to be orthogonal to) the tubular member  131  in the third transporting mechanism  130 . In other words, the tubular member  141  is arranged to extend in the approximately horizontal direction. Moreover, the fourth transporting mechanism  140  includes a transporting member  142  that is disposed inside the tubular member  141 , and that transports the waste toner from the third transporting mechanism  130 . Further, the fourth transporting mechanism  140  includes a fourth motor M 4  that rotationally drives the transporting member  142 . 
     The fifth transporting mechanism  150  includes a tubular member  151  that forms a transport path for the waste toner. The tubular member  151  is disposed below the tubular member  141  in the fourth transporting mechanism  140 , and also is arranged parallel to the tubular member  141 . The fifth transporting mechanism  150  further includes a transporting member  152  and a fifth motor M 5 . The transporting member  152  is disposed inside the tubular member  151 , and transports the waste toner from the fourth transporting mechanism  140 . The fifth motor M 5  rotationally drives the transporting member  152 . 
     Here,  FIG. 4  is an enlarged view showing the fourth transporting mechanism  140  and the fifth transporting mechanism  150 . With reference to  FIG. 4 , the fourth transporting mechanism  140  and the fifth transporting mechanism  150  will be further described. 
     The transporting member  142  in the fourth transporting mechanism  140  includes: a rotational shaft  142 A that is rotated by the fourth motor M 4  (see  FIG. 2 ); and ridge portions  142 B each provided to project from an outer peripheral surface of the rotational shaft  142 A. The ridge portions  142 B are provided in the form of fins around the rotational shaft  142 A, and also provided in a helical (screw) shape along the axis of the rotational shaft  142 A. 
     In addition, the tubular member  141  in the fourth transporting mechanism  140  includes a discharge outlet  141 A at a lower portion in an end portion on the fifth transporting mechanism  150  side. Through the discharge outlet  141 A, the waste toner having been transported by the transporting member  142  is discharged to the tubular member  151  in the fifth transporting mechanism  150 . 
     On the other hand, as is the case with the transporting member  142 , the transporting member  152  in the fifth transporting mechanism  150  also includes: a rotational shaft  152 A that is rotated by the fifth motor M 5  (see  FIG. 2 ); and ridge portions  152 B each provided to project from the rotational shaft  152 A. The ridge portions  152 B are provided in the form of fins around the rotational shaft  152 A, and also provided in a helical (screw) shape along the axis of the rotational shaft  152 A. Here, the transporting member  152  is provided along the transport path for waste toners formed by the tubular member  151 . Moreover, the transporting member  152  is also provided to extend from the first discharge outlet  151 A to the second discharge outlet  151 B, both of which will be described later. 
     In addition, the tubular member  151  in the fifth transporting mechanism  150  includes a receiving port  151 C that receives the waste toner from the discharge outlet  141 A in the fourth transporting mechanism  140 . Moreover, the tubular member  151  includes the first discharge outlet  151 A. Through the first discharge outlet  151 A, the waste toner having been received by the receiving port  151 C and transported by the transporting member  152  is discharged to the first storing container  210  (see  FIG. 2 ). Furthermore, the tubular member  151  includes the second discharge outlet  151 B. Through the second discharge outlet  151 B, the waste toner having been received by the receiving port  151 C and transported by the transporting member  152  is discharged to the second storing container  220  (see  FIG. 2 ). 
     Here, in the present exemplary embodiment, the first discharge outlet  151 A is provided at a lower portion in one end portion of the tubular member  151 , while the second discharge outlet  151 B is provided at a lower portion in the other end portion of the tubular member  151 . Meanwhile, the receiving port  151 C is provided at an upper portion of the tubular member  151  between the first discharge outlet  151 A and the second discharge outlet  151 B. 
     Here, for example, when the fifth motor M 5  (see  FIG. 2 ) in the fifth transporting mechanism  150  is rotating in the forward direction, the forward rotation of the fifth motor M 5  causes the transporting member  152  to be rotationally driven so as to transport the waste toner from the discharge outlet  141 A to the second discharge outlet  151 B. The waste toner thus transported to the second discharge outlet  151 B falls down through the second discharge outlet  151 B into the second storing container  220  located below the second discharge outlet  151 B. Then, for example, if the second storing container  220  is filled up with the waste toner or removed, the controller  21  causes the fifth motor M 5  to rotate in the reverse direction. The reverse rotation of the fifth motor M 5  causes the transporting member  152  to be rotationally driven in the reverse direction so as to transport the waste toner from the discharge outlet  141 A to the first discharge outlet  151 A. The waste toner thus transported to the first discharge outlet  151 A falls down through the first discharge outlet  151 A into the first storing container  210  located below the first discharge outlet  151 A. 
     In the present exemplary embodiment, the amount of the waste toner to be transported per unit time in the fourth transporting mechanism  140  is set to be not less than the amount of the waste toner to be transported per unit time in the second transporting mechanism  120 . Accordingly, during a normal operation, the waste toner is basically not accumulated inside the tubular member  131 . In other words, during the normal operation, the tubular member  131  has enough space for the accumulation of the waste toner. In addition, in the present exemplary embodiment, the amount of the waste toner to be transported per unit time in the second transporting mechanism  120  is set to be larger than the amount of the waste toner to be transported per unit time by the transporting members  341  (see  FIG. 1 ) provided in the respective cleaning units  34 . Accordingly, as in the case of the tubular member  131 , during the normal operation, the tubular member  111  of each of the first transporting mechanisms  110  has enough space for the accumulation of the waste toner. 
     Here,  FIG. 5  is a diagram showing the control block of the controller  21 . Note that,  FIG. 5  shows only the block concerning the transportation of the waste toner. 
     The controller  21  includes a central processing unit (CPU)  211 , a read only memory (ROM)  212 , and a random access memory (RAM)  213 . The CPU  211  of the controller  21  performs processing described below while exchanging data with the RAM  213 , in accordance with a program stored in the ROM  212 . 
     Here, the controller  21  receives outputs from the first to fourth sensors S 1  to S 4 , the temperature sensor S 5 , and the humidity sensor S 6 , via an input/output interface  214 . In addition, the controller  21  acquires, from the image processing part  22 , image data inputted to the image processing part  22 . Moreover, the controller  21  controls the first to sixth motors M 1  to M 6  via the input/output interface  214 . 
     Subsequently, the process of transporting the waste toner performed by the controller  21  will be described in detail. 
       FIG. 6  is a diagram showing an operation sequence of the first to fifth motors M 1  to M 5  provided respectively to the first to fifth transporting mechanisms  110  to  150  as well as the sixth motor M 6  (not shown in the figure) that rotationally drives the photoconductor drums  31 . Note that, as an example of this operation sequence, an operation when the second storing container  220  is further removed with the first storing container  210  having already been removed will be described. In short, the operation when both of the first and second storing containers  210  and  220  are removed will be described as an example. 
     As shown in  FIG. 6 , upon detecting that the second storing container  220  is removed on the basis of the output from the second sensor S 2 , the controller  21  stops the driving of the third motor M 3  in the third transporting mechanism  130 , the fourth motor M 4  in the fourth transporting mechanism  140 , and the fifth motor M 5  in the fifth transporting mechanism  150 . As a result, the transportation of the waste toner by the transporting member  152  is stopped, so that the waste toner is prevented from being discharged from the second discharge outlet  151 B in a state where the second storing container  220  is not mounted. In addition, the transportation of the waste toner to the fifth transporting mechanism  150  having been stopped is stopped, while the reciprocation of the coil spring  132  in the third transporting mechanism  130  is also stopped. 
     Here, in the present exemplary embodiment, when removal of the second storing container  220  is detected, the driving of the third motor M 3  and the like is stopped as described above. Incidentally, another configuration may be employed, for example, in which a cover member (not shown in the figure) or the like that is designed to be opened for the removal of the second storing container  220  is provided, and the driving of the third motor M 3  and the like is stopped upon detection of the opening of the cover member. 
     On the other hand, the controller  21  continues the driving of the first motors M 1  in the respective first transporting mechanisms  110 , the second motor M 2  in the second transporting mechanism  120 , and the sixth motor M 6  until a time T 1  passes after stopping the driving of the third motor M 3 , the fourth motor M 4 , and the fifth motor M 5 . In this event, until the time T 1  passes, the discharge of the waste toner from the cleaning units  34  (see  FIG. 1 ) is continued, and also, the transportation of the waste toner to the tubular member  131  in the third transporting mechanism  130  is continued. 
     Then, the waste toner having been transported to the tubular member  131  falls down inside the tubular member  131 , and is deposited inside the tubular member  131 . In other words, the waste toner is accumulated inside the tubular member  131 . Then, unless any one of the first and second storing containers  210  and  220  is mounted before the time T 1  passes, the controller  21  stops the driving of the first and second motors M 1  and M 2  so as to stop the transportation of the waste toner, and also stops the driving of the sixth motor M 6  so as to stop the image forming operation. Note that, in the present exemplary embodiment, if any one of the first and second storing containers  210  and  220  is not mounted before the time T 1  passes, the first motor M 1  and the like are stopped. Alternatively, another configuration may be employed, for example, in which a sensor or the like is provided to a side portion or the like of the tubular member  131 , and the first motor M 1  and the like are stopped if the sensor or the like detects that the waste toner reaches a predetermined position inside the tubular member  131 . 
     On the other hand, if any one of the first and second storing containers  210  and  220  is mounted before the time T 1  passes, the controller  21  restarts the driving of the third to fifth motors M 3  to M 5  (illustration thereof is omitted). In addition, during this period, the controller  21  does not stop but continues the driving of the first, second, and sixth motors M 1 , M 2 , and M 6 . With this configuration, the transportation of the waste toner having been accumulated inside the tubular member  131  to the storing container is started, while the transportation of the waste toner in the first and second transporting mechanisms  110  and  120  as well as the image forming operation are continued. As described above, in the present exemplary embodiment, the image forming operation is allowed to be continued without interruption if any one of the first and second storing containers  210  and  220  is mounted before the time T 1  passes. Suppose the case where the cover member is provided as described above. In this case, a configuration may be employed in which, if the cover member is closed before the time T 1  passes, for example, the driving of the third to fifth motors M 3  to M 5  is restarted while the driving of the first, second, and sixth motors M 1 , M 2 , and M 6  is continued. 
     Consider the case where the driving of the third to fifth motors M 3  to M 5  is restarted in response to any one of the first and second storing containers  210  and  220  being mounted before the time T 1  passes. Even in this case, since the transportation of the waste toner from the second transporting mechanism  120  is continued, the state where the waste toner is being accumulated inside the tubular member  131  may still be maintained. In other words, the state where the space available for accumulating the waste toner is being reduced inside the tubular member  131  may be maintained. For this reason, the waste toner may be discharged from the tubular member  131  by driving the third to fifth motors M 3  to M 5  at the timing when the image forming operation is not performed. 
     Note that, in the present exemplary embodiment, the reciprocation of the coil spring  132  is stopped by stopping the driving of the third motor M 3  when the removal of the second storing container  220  is detected. Alternatively, the reciprocation of the coil spring  132  may be continued even in this case. However, if the reciprocation of the coil spring  132  is continued, the waste toner inside the tubular member  131  is pressed by the coil spring  132 , thus being likely to be agglomerated. For this reason, at the same time when the driving of the fourth and fifth motors M 4  and M 5  is stopped, the reciprocation of the coil spring  132  may be stopped. Note that, although the configuration where the coil spring  132  is provided has been illustrated as the example in the present exemplary embodiment, the coil spring  132  may be omitted. 
     Moreover, the controller  21  may change the time T 1  depending on the environment inside the image forming apparatus  1 . For example, if the temperature or humidity in the image forming apparatus  1  is high, the fluidity of the waste toner decreases, so that the waste toner is less likely to fall down inside the tubular member  131 . In other words, such an environment may cause a situation where the waste toner is less likely to be accumulated inside the tubular member  131 . Then, if the transportation of the waste toner is continued under such condition, the clogging or the like of the waste toner may occur inside the tubular member  121 , for example. For this reason, the controller  21 , functioning also as a changing section, changes the time T 1  to a shorter time, for example, if the temperature or humidity (examples of environmental information) inside the image forming apparatus  1  is larger than a predetermined value, for example. On the other hand, if the temperature or humidity in the image forming apparatus  1  is low, the waste toner is more likely to flow. For this reason, the controller  21  changes the time T 1  to a longer time if the temperature or humidity inside the image forming apparatus  1  is lower than a predetermined value, for example. Note that, the controller  21  finds out the temperature and humidity on the basis of the outputs from the temperature sensor S 5  and the humidity sensor S 6 . 
     Furthermore, the controller  21  may change the time T 1  depending on the amount of the waste toner to be transported to the tubular member  131  (the amount of the waste toner to be discarded in the image forming process part  20 ). For example, the controller  21  changes the time T 1  to a shorter time if the amount of the waste toner to be transported to the tubular member  131  is larger than a predetermined amount. On the other hand, for example, the controller  21  changes the time T 1  to a longer time if the amount of the waste toner to be transported to the tubular member  131  is smaller than a predetermined amount. Note that, for example, the controller  21  may find out a density of an image on the basis of image data outputted to the image processing part  22  from the image reading apparatus  4  or the PC  5 , and then find out the amount of the waste toner to be transported to the tubular member  131  on the basis of the density of the image thus found out. 
     Here,  FIG. 7  is a diagram showing a return sequence of the transporting mechanism  100  and the like. 
     As described above, if any one of the first and second storing containers  210  and  220  is not mounted within the time T 1 , the first motor M 1  and the like are stopped, so that the transportation of the waste toner by the transporting mechanism  100  is stopped.  FIG. 7  shows an operation of returning from the state where the transportation is stopped. 
     Upon detecting that the second storing container  220 , for example, is mounted, the controller  21  first starts the driving of the third to fifth motors M 3  to M 5 . The discharge of the waste toner to the second storing container  220  is thus restarted, and also, the waste toner having been accumulated inside the tubular member  131  starts to be discharged to the outside of the tubular member  131 . 
     Thereafter, the controller  21  starts the driving of the first, second, and sixth motors M 1 , M 2 , and M 6  after a time T 2  passes from the restart of the driving of the third motor M 3  and the like. The transportation of the waste toner having been located inside the first and second transporting mechanisms  110  and  120  is thus restarted, and also, the photoconductor drums  31  are rotationally driven to allow the image forming operation. 
     Note that, the time T 2  may be set to be not less than a time required for the waste toner inside the tubular member  131  to be discharged to the outside of the tubular member  131 . In other words, the driving of the first, second, and sixth motors M 1 , M 2 , and M 6  may be restarted after the waste toner inside the tubular member  131  is discharged to the outside of the tubular member  131 . If the driving of the first motor M 1  and the like is restarted before the waste toner inside the tubular member  131  is discharged to the outside of the tubular member  131 , the state where the waste toner is accumulated inside the tubular member  131  is maintained in some cases. In other words, the state where the space available for accumulating the waste toner is small inside the tubular member  131  is maintained in some cases. 
     Here,  FIG. 8  is a diagram showing another example of the operation sequence of the first to sixth motors M 1  to M 6 . Note that, also as an example of this operation sequence, an operation when the second storing container  220  is further removed with the first storing container  210  having already been removed will be described. In short, the operation when both of the first and second storing containers  210  and  220  are removed will be described as an example. 
     Upon detecting that the second storing container  220  is removed, the controller  21  stops the driving of the third to fifth motors M 3  to M 5  as in the case described above. Thereafter, the controller  21  stops the driving of the second motor M 2  after a time T 3  passes from the detection of the removal of the second storing container  220 , for example. Subsequently, the controller  21  stops the driving of the first and sixth motors M 1  and M 6  after the time T 1  passes from the detection of the removal of the second storing container  220 , for example, as in the case described above. 
     In the transporting mechanism  100  in the present exemplary embodiment, the tubular member  111  in each of the first transporting mechanisms  110  also has space allowing the waste toner to be accumulated therein. In the processing, the waste toner is accumulated also in the space in the tubular member  111 . This configuration increases the amount of the waste toner to be accumulated. As a result, the time T 1 , which serves as the reference for the timing to stop the first and sixth motors M 1  and M 6  (to stop the image forming operation), may be extended as compared with the aforementioned processing shown in  FIG. 6 . 
     To be more specific, the driving of the second motor M 2  is continued until the time T 3  passes after the detection of the removal of the second storing container  220 . The continuous driving of the second motor M 2  first causes the waste toner to be accumulated inside the tubular member  131 . Then, in the processing, while the driving of the second motor M 2  is stopped after the time T 3  passes, the driving of the first and sixth motors M 1  and M 6  is continued. This configuration causes the waste toner having been transported by the transporting member  341  of each cleaning unit  34  to be accumulated inside the corresponding tubular member  111 . 
     Note that, in the return sequence, for example, the driving of the third to fifth motors M 3  to M 5  is first started so as to discharge the waste toner from the tubular member  131 . Thereafter, the driving of the second motor M 2  is started so as to discharge the waste toner from the tubular members  111 . Subsequently, the driving of the first motor M 1  as well as the driving of the sixth motor M 6  are started so as to restart the image forming operation. Note that, the driving of the second motor M 2  may be started after the waste toner is discharged from the tubular member  131 , as in the case described above. In addition, the driving of the first and sixth motors M 1  and M 6  may be started after the waste toner is discharged from the tubular members  111 . 
     Note that, in the above description, after the driving of the third to fifth motors M 3  to M 5  is started, the driving of the second motor M 2  is started, and subsequently, the driving of the first motor M 1  is started. However, both of the first and second motors M 1  and M 2  may be started to be driven after the driving of the third to fifth motors M 3  to M 5  is started. 
     Moreover, a motor (not shown in the figure) (hereinafter, referred to as a “seventh motor M 7 ”), which drives the coil spring  112  in each tubular member  111  may be separately provided. In this case, in the return sequence, the driving of the third to fifth motors M 3  to M 5  is first started, for example. Subsequently, the driving of the second and seventh motors M 2  and M 7  is started. After that, the driving of the first and sixth motors M 1  and M 6  is started. 
     The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The exemplary embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.