Abstract:
An image forming apparatus includes: an image forming apparatus main body, a driven member removably disposed in the image forming apparatus main body, a rotary driver that rotates by current flowing, and after the blockage of the current flowing, continuously rotates due to an inertial force, a coupling part that has a driving-side member and a driven-side member, wherein when the driven-side member is mounted to the image forming apparatus main body, the driving-side member and a driven-side member are facing each other, and when the driving-side member and the driven-side member engage each other in the rotating direction, the rotary driver and the driven-side member are coupled to transmit the rotation of the rotary driver to the driven-side member, and a controller that controls so that, when the driven-side member is mounted to the image forming apparatus main body, the current flows to the rotary driver, and after the elapse of a certain period of time the current flow to the rotary driver is blocked.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2009-214468 filed Sep. 16, 2009. 
     BACKGROUND 
     Technical Field 
     The present invention relates to an image forming apparatus. 
     SUMMARY 
     According to an aspect of the invention, there is provided an image forming apparatus including: an image forming apparatus main body, a driven member removably disposed in the image forming apparatus main body, a rotary driver that rotates by current flowing, and after the blockage of the current flowing, continuously rotates due to an inertial force, a coupling part that has a driving-side member and a driven-side member, wherein when the driven-side member is mounted to the image forming apparatus main body, the driving-side member and a driven-side member are facing each other, and when the driving-side member and the driven-side member engage each other in the rotating direction, the rotary driver and the driven-side member are coupled to transmit the rotation of the rotary driver to the driven-side member, and a controller that controls so that, when the driven-side member is mounted to the image forming apparatus main body, the current flows to the rotary driver, and after the elapse of a certain period of time the current flow to the rotary driver is blocked. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  is a cross-sectional view illustrating an entire configuration of an image forming apparatus  10  according to an exemplary embodiment of the present invention, 
         FIG. 2  is a diagram illustrating a hardware configuration of a controller  14  disposed in the image forming apparatus  10 , 
         FIG. 3  is a view illustrating a state where an image forming unit  130  is removed from an image forming apparatus main body  12 , 
         FIG. 4  is an explanatory view explaining the attachment and removal of the image forming unit  130 , 
         FIG. 5  is a view illustrating a periphery of the coupling part between the image forming apparatus main body  12  and an image carrier  70 , 
         FIG. 6  is a perspective view of a coupling  200 , 
         FIG. 7  is a flowchart of a first exemplary embodiment according to the present invention that illustrates an operation (S 10 ) executed by a controller  14  in mounting of the image forming unit  130 , and 
         FIG. 8  is a flowchart of a second exemplary embodiment according to the present invention that illustrates an operation (S 20 ) executed by a controller  14  in mounting the image forming unit  130 . 
     
    
    
     DETAILED DESCRIPTION 
     First Exemplary Embodiment 
     The exemplary embodiment of the present invention will be described below with reference to accompanying drawings. 
       FIG. 1  illustrates an entire configuration of an image forming apparatus  10  according to the exemplary embodiment of the present invention. The image forming apparatus  10  has an image forming apparatus main body  12  which has a controller  14  controlling every part of the image forming apparatus  10 . In the front side of the image forming apparatus main body  12  (the left side face in  FIG. 1 ), an open-close cover  18   a  turnable around a pivot  16   a  is disposed. Further, in the upper side of the image forming apparatus main body  12 , an open-close cover  18   b  turnable around a pivot  16   b  is disposed. The open-close covers  18   a  and  18   b  provide the opening and closing of an opening  19  as shown in  FIG. 3 . An interlock switch  20  serving as an open-close detector is disposed in the free end side of the open-close cover  18   a , and by single-use allows the detection of the opening and closing state of the open-close covers  18   a  and  18   b . A recording medium supply unit  21  which is e.g. an one-stage unit is disposed in the lower part of the image forming apparatus main body  12 . 
     The recording medium supply unit  21  has a recording medium supply unit main body  22  and a recording medium supply cassette  24  storing a recording medium. In the innermost end and approximate upper part of the recording medium supply cassette  24 , a feed roller  26  feeding a recording medium and a separation roller  28  separating a fed recording medium are disposed. 
     A transport path  30  being a recording medium passage from the feed roller  26  to an exit  32  is positioned at the approximate backside of the image forming apparatus main body  12  (the right side face in  FIG. 1 ), and has an approximate vertical part from the recording medium supply unit  21  to a fixing device  120  to be described later. A secondary transfer roller  102  and a secondary transfer backup roller  92  to be described later are arranged in upstream side of the fixing device  120 . Further, a registration roller  40  is arranged in the upstream side of the secondary transfer roller  102  and the secondary transfer backup roller  92 . Furthermore, an exit roller  42  is arranged in the vicinity of the exit  32  along the transport path  30 . 
     Thus, an uppermost recording medium which is fed by the feed roller  26  from the recording medium supply cassette  24  of the recording medium supply unit  21  is separated by the separation roller  28  and is guided to the transport path  30 . The recording medium led to the transport path  30  is temporarily stopped with the registration roller  40 , and is subjected to the transferring of a toner image by passing between the secondary transfer roller  102  and the secondary transfer backup roller  92  at predetermined timing. Subsequently, the transferred toner image is fixed on the recording medium with the fixing device  120 , and further the recording medium is exited through the exit  32  toward an exit part  44 , positioned on an upper part of the open-close cover  18 , with an exit roller  42 . The exit part  44  is configured so as to be tilted upward from the exit  32  side toward the front side of the image forming apparatus  10  (the left side face in  FIG. 1 ). 
     A rotary developing device  50  is disposed at e.g. an approximate central part of the image forming apparatus main body  12 . The rotary developing device  50  has a developing device main body  52 . The developing device  52  has developing units  54 Y,  54 M,  54 C, and  54 K respectively forming each of four color toner images of yellow, magenta, cyan, and black developers. The rotary developing device  50  rotates around a center  56  in the left direction (counterclockwise rotation in  FIG. 1 ). As a typical example of the exemplary embodiment, components forming a yellow toner image are denoted by reference numerals in  FIG. 1 . 
     Each of developing units  54 Y,  54 M,  54 C, and  54 K is applied in two component development method, and has a developer supply member (not shown) supplying a toner to developing containers  58 Y,  58 M,  58 C, and  58 K and developing rollers  60 Y,  60 M,  60 C, and  60 K. The developing units  54 Y,  54 M,  54 C, and  54 K are respectively pressed with each of elastic members  62 Y,  62 M,  62 C, and  62 K consisting of e.g. a coil spring in a normal direction of the developing device main body  52 . 
     The rotary developing device  50  is arranged so as to contact with an image carrier  70  consisting of e.g. a photoreceptor. The developing rollers  60 Y,  60 M,  60 C, and  60 K are respectively arranged in the state where a part of the circumference of each developing roller  60 Y,  60 M,  60 C, and  60 K radially juts out from the circumference of the developing device main body  52  by e.g. 2 mm, but the juts do not abut on the image carrier  70 . Further, each of the developing rollers  60 Y,  60 M,  60 C, and  60 K has, at both ends of the axis, a tracking roller whose diameter is slightly bigger than the diameter of the developing rollers  60 Y,  60 M,  60 C, and  60 K (not shown) to rotates on the same axis as the developing rollers  60 Y,  60 M,  60 C, and  60 K. That is, when the tracking roller abuts on a flange disposed at both ends of the axis of the image carrier  70 , a given interspace is formed between each of the developing rollers  60 Y,  60 M,  60 C, and  60 K and the image carrier  70 , and then, a latent image formed on the image carrier  70  is developed with each color toners. 
     Down the image carrier  70 , a charging device  72  consisting of e.g. a charging roller and uniformly charging the image carrier  70  is disposed. Further an image carrier cleaner  74  is positioned short of the charging device  72  in the rotating direction of the image carrier  70  so as to contact with the image carrier  70 . The image carrier cleaner  74  consists of e.g. a cleaning blade  76  for scraping off toner particles remaining on the image carrier  70  and a waste toner bottle  78  for collecting the scrapped toner particles. 
     Down the rotary developing device  50 , an optical writing device  80  for writing a latent image to the image carrier  70  charged by the charging device  72 , with beam such as laser, is arranged. Above the rotary developing device  50 , an intermediate transfer device  82  which allows a toner image visualized with the rotary developing device  50  to be firstly transferred at a primary transfer position and subsequently sends the transferred toner image to a secondary transfer position is disposed. 
     The intermediate transfer device  82  consists of e.g. an intermediate transfer member  84  such as an intermediate transfer belt, a primary transfer roller  86 , a wrap-in roller  88 , a wrap-out roller  90 , a secondary transfer backup roller  92 , a scraper backup roller  94 , and a brush backup roller  96 . 
     The intermediate transfer member  84  having e.g. elasticity is approximately flatly tightened so as to have a longer side and a shorter side above the rotary developing device  50 . The longer side part of the upper surface of the intermediate transfer member  84  is formed so as to be approximate parallel relative to the exit part  44  disposed in the upper part of the image forming apparatus main body  12 . Further on the under side of the longer side of the intermediate transfer member  84 , a primary transfer part which contacts the image carrier  70  in a wrapping manner between the wrap-in roller  88 , arranged upstream of the primary transfer roller  86 , and a wrap-out roller  90 , arranged downstream of the primary transfer roller  86  is disposed. The intermediate transfer member  84  wraps around the image carrier  70  only over a predetermined range to rotate according to the rotary of the image carrier  70 . 
     As described above, the intermediate transfer member  84  is subjected to the primary transfer by superposing each color toner image, e.g. yellow, magenta, cyan, and black, of the image carrier  70 , in order with the primary transfer roller  86 . The toner image superposed by the primary transfer is transported toward a secondary transfer roller  102  to be described later. 
     Note that the wrap-in roller  88  and the wrap-out roller  90  are separated from the image carrier  70 . 
     In the back side of the intermediate transfer member  84  (the right side face in  FIG. 1 ), a flat portion (the shorter side part) is formed by the wrap-out roller  90  and the secondary transfer backup roller  92 . The flat portion serving as a secondary transfer part faces to the transfer path  30 . 
     The scraper backup roller  94  allows a scraper  106  to be descried later to scrape off a toner particles remaining on the intermediate transfer member  84  after a secondary transfer. The brush backup roller  96  allows the brush roller  108  to be described later to scrap off a toner particles remaining on the intermediate transfer member  84  after the secondary transfer. 
     An intermediate transfer sensor  100  such as a reflective photosensor is disposed above the longer side of the intermediate transfer member  84 . The intermediate transfer sensor  100  reads plural marks, e.g. two position marks P arranged on the intermediate transfer member  84  to detect to the rotary motion and the rotary direction of the intermediate transfer member  84 . That is, the intermediate transfer sensor  100  determines the rotary motion of the intermediate transfer member  84  from the interval of time between the detection of a first position mark P and the detection of a second position mark P. 
     The secondary transfer backup roller  92  of the intermediate transfer device  82  and the secondary transfer roller  102  are arranged so as to sandwich the transport path  30  and to be opposite each other. The secondary transfer position of the secondary transfer part is between the secondary transfer roller  102  and the secondary transfer backup roller  92 , and at the secondary transfer position, the secondary transfer roller  102  performs the secondary transfer by using the toner image superposed on the intermediate transfer  84  by the primary transfer, onto a recording medium with the secondary transfer back-up roller  92 . While the intermediate transfer member  84  rotates e.g. three times, that is, during the transportation of three toner images with yellow, magenta, and cyan color toners, the secondary transfer roller  102  separates from the intermediate transfer member  84 . Further, after completion of transfer of the black toner, the secondary transfer roller  102  contacts the intermediate transfer member  84 . 
     An intermediate transfer cleaner  104  is disposed so as to contact with the end of the intermediate transfer  84 , which is opposite the one end adjacent to the image carrier  70 . The intermediate transfer cleaner  104  consists of e.g. a scraper  106  for scraping a toner particles remaining on the intermediate transfer member  84  after the secondary transfer to clean the intermediate transfer member  84 , a brush roller  108  for further scraping toner particles remaining following the cleaning by the scraper  106 , and a waste toner bottle  110  for collecting the toner particles scraped by the scraper  106  and the brush roller  108 . 
     The scraper  106  is made of e.g. a thin sheet of a stainless steel, and is supplied the opposite polarity relative to the toner voltage supply. The brush roller  108  is made of e.g. an acrylic brush subjected to conductive treatment. The scraper  106  and the brush roller  108  are arranged so as to be separate from the intermediate transfer member  84  during the transportation of the toner image by the intermediate transfer member  84 , and at a predetermined timing contact the intermediate transfer member  84  in an integrated manner. 
     A fixing device  120  is arranged above the secondary transfer position. The fixing device  120  has a heating roller  122  and a pressure roller  124  for transporting a recording medium, on which the toner image is fixed after completion of the secondary transfer, toward the exit roller  42 . 
     An image forming unit  130  is configured by integrating the intermediate transfer device  82 , the image carrier  70 , the charging device  72 , the image carrier cleaner  74 , and the intermediate transfer cleaner  104 . The image forming unit  130  is arranged below proximal the exit part  44  of the open-close cover  18   b , and is removable against the image forming apparatus main body  12  with the open-close cover  18   a  and  18   b  opened or closed. 
     A touch panel  132  for inputting and displaying by and to an operator is disposed in the front side of the image forming apparatus main body  12  (The left side face in  FIG. 1 ). The touch panel  132  is controlled by a user interface (UI)  140  to be described later. 
     If an image is continuously formed on a recording medium with a resolution that is below a predetermined value, since each developer of the developing units  54 Y,  54 M,  54 C, and  54 K circulate long time, and has high charge, the toner on the image carrier  70  deteriorates and thereby the image deterioration causes. The image forming apparatus  10  is configured so that the deteriorated toner is exited from the developing units  54 Y,  54 M,  54 C, and  54 K for preventing the image deterioration. 
     The image forming apparatus  10  is configured so that the deteriorated toner is exited (removed) from each of the developing units  54 Y,  54 M,  54 C, and  54 K, for instance, by using a controller  14  which provides the superposition of each predetermined color toner image on a predetermined section of the image carrier  70  and controls the image carrier cleaner  74  to scrap the toner image with the deteriorated toner particles. 
     The image forming apparatus  10  further may be configured so that the deteriorated toner is exited (removed) from each of the developing units  54 Y,  54 M,  54 C, and  54 K, by using a controller  14  which provides the superposition of each predetermined color toner image on a predetermined section of the image carrier  70  and controls the image carrier cleaner  104  to scrap the toner image with the deteriorated toner particles. 
       FIG. 2  shows a hardware configuration of the controller  14 . The controller  14  has a CPU  134 , a memory  136 , a storage device  138  such as a hard-disk drive, the UI  140 , and a switch  142  for turning on or off a rotary driver  206  to be described later. The above components are connected to each other via a bus  144  so as to be capable of inputting and outputting information each other. 
     Next, the attachment and removal of the image forming unit  130  will be described below. 
       FIG. 3  shows a diagram illustrating the image forming unit  130  is removed from the image forming apparatus main body  12 . The image forming unit  130  is removed through the opening  19 , which is opened at the time where the open-close covers  18   a  and  18   b  entirely open in order, in a diagonally forward direction of the image forming apparatus main body  12  (The left diagonally upward side in  FIG. 3 ). 
       FIG. 4  shows a configuration diagram of the attachment and removal of the image forming unit  130 . The image forming unit  130  is attached or removed to or from the image forming unit main body  12  by a main guide unit  152  and an auxiliary guide unit  154  in a predetermined direction. 
     The main guide unit  152  consists of e.g. a guide groove  156  disposed in the image forming apparatus main body  12  and a main projection  158  disposed in the image forming unit  130 . The main projection  158  is formed, for instance, cylindrically on the same axis as the image carrier  70 , so as to fit in the guide groove  156 , and move along the guide groove  156 . 
     The auxiliary guide unit  154  consists of e.g. an auxiliary groove  160  disposed in the image forming apparatus main body  12  and an auxiliary projection  162  disposed in the image forming unit  130 . The auxiliary projection  162  is formed, for instance, cylindrically so as to fit in the auxiliary groove  160  and move along the auxiliary groove  160 . The auxiliary groove  160 , in which the upper side is wider than the lower side, facilitates fitting of the auxiliary projection  162  to the auxiliary groove  160 . 
     The guide groove  156  has a contacting and departing guide groove  164  formed in the lower part of the guide groove  156  at an angle A from the horizontal, and a displacing guide groove  166  formed in the upper part of the guide groove  156  at an angle B from the horizontal. The auxiliary groove  160  has a contacting and departing auxiliary guide groove  168  formed in the lower part of the auxiliary groove  160  at an angle A from the horizontal, and a displacing auxiliary guide groove  170  formed in the upper part of the auxiliary groove  160  at an angle B from the horizontal. The angle A is e.g. 70-degree, and the angle B is e.g. 55-degree. Therefore, the main projection  158  and the auxiliary projection  162  respectively move along the contacting and departing guide groove  164  and the contacting and departing auxiliary guide groove  168  each other, thereby the image forming unit  130  in the approximate tangential direction of the rotary developing device  50  is moved toward the direction for contacting and departing to and from the image forming apparatus main body  12 . 
     In addition, the main projection  158  and the auxiliary projection  162  respectively move along the displacing guide groove  166  and the displacing auxiliary guide groove  170  each other, thereby the image forming unit  130  is moved toward the approximate tangential direction in which the image forming unit  130  passes thorough the developing position of the rotary developing device  50 . 
     As described above, the main projection  158  and the auxiliary projection  162  respectively move along the guide groove  156  and the auxiliary groove  160  each other, thereby the image forming unit  130  is attached or removed to or from the image forming apparatus main body  12  in a predetermined posture in the approximate tangential direction having the developing portion of the rotary developing device  50 . 
     The lower end of the guide groove  156  is formed so that the shaft (center) corresponding to both of the image carrier  70  and the main projection  158  is positioned in the normal line extending from a center  56  of the rotary developing device  50  at an angle C from the horizontal, and the image carrier  70  and the main projection  158  are received thereon. The angle C is e.g. 25-degree. Thus, the image carrier  70  is located at a predetermined developable position with the main projection  158  received on the lower end of the guide groove  156 , so as to avoid displacement caused by the press of the rotary developing device  50 . 
     In the removal of the image forming unit  130 , the open-close covers  18   a  and  18   b  open together, and as a result, the opening  19  is entirely opened. 
     When the image forming unit  130  is located at a predetermined developable position (an appropriate position), the open-close covers  18   a  and  18   b  are capable of closing. That is, the open-close covers  18   a  and  18   b  appropriately close, and an interlock switch  20  detects the completion of the closing of the open-close covers  18   a  and  18   b  when the image forming unit  130  is located at an appropriate position. 
     When the image forming unit  130  is inappropriately located, it is configured that the open-close covers  18   a  and  18   b  are unable to appropriately close due to the insufficient attachment of the image forming unit  130 . That is, when the image forming unit  130  is inappropriately located, the interlock switch  20  detects the insufficient closing of the open-close covers  18   a  and  18   b.    
     When the open-close covers  18   a  and  18   b  open, a recording medium placed on the exit part  44  never falls down because one end of the recording medium moving relative to opening or closing motion of the open-close cover  18   b  is supported at a pivot  16   b  side of the open-close cover  18   b  (the exit part  44 ). 
     The attachment of the image forming unit  130  is performed in the reverse procedure to the removal of the image forming unit  130 . 
     Next, a perimeter configuration of a portion where the image forming apparatus main body  12  and the image carrier  70  of the image forming unit  130  connect together will be described. 
       FIG. 5  shows a diagram of the perimeter configuration of the coupling portion where the image forming apparatus main body  12  and the image carrier  70  connect together, and  FIG. 6  shows a perspective view of a coupling  200 . 
     The image carrier  70  of the image forming unit  130  has at least a part of the coupling  200  being an example of a coupling device associated with the image forming apparatus main body  12 . The coupling  200  has a coupling member  202  disposed in the image forming apparatus main body  12  and a coupled member  204  disposed in the image carrier  70 . The coupling member  202  and the coupled member  204  are removably coupled together. 
     When a coupling projected part  202   a  of the coupling member  202  and a coupled projected part  204   a  of the coupled member  204  abut together at the laterals facing in a circumferential direction of both of the coupling member  202  and the coupled member  204 , the coupling between the coupling member  202  and the coupled member  204  occurs. 
     In contrast, when the coupling projected part  202   a  and the coupled projected part  204   a  abut together at the surfaces facing in the rotary axis direction of both the coupling member  202  and the coupled member  204 , the coupling between the coupling member  202  and the coupled member  204  is inappropriate. 
     The coupling member  202  is connected to a rotary driver  206  providing the rotation of the coupling member  202 . At the coupling  200 , the rotation driven by the rotary driver  206  is transmitted to the image carrier  70 . 
     The rotary driver  206  consists of e.g. a DC motor or the like, and is connected to the switch  142  for turning on or off a rotary driver  206  by controlled with the controller  14 . When the switch  142  is turned on, the rotary driver  206  drives to rotate the coupling member  202  at a certain speed. When the switch  142  is turned off, the rotary driver  206  stops the driving. After the stop of the driving, the coupling member  202  rotates several times (around 1 to 5 rotations) due to an inertial force. 
     An urging part  208  such as a spring is mounted on the coupling member  202 . The urging part  208  is configured so as to work with opening or closing motion of the open-close covers  18   a  and  18   b . Specifically, when the open-close covers  18   a  and  18   b  close after the completion of the appropriate attachment of the image forming unit  130 , the urging part  208  urges the coupling member  202  in the direction of the image carrier  70  (the direction of the coupled member  204 ) in conjunction with the closing. When the open-close covers  18   a  and  18   b  open, the urging part  208  stops urging the coupling member  202  in the direction of the image carrier  70 . 
     When the rotary driver  206  drives and subsequently stops the driving during the closing of the open-close covers  18   a  and  18   b , the coupling member  202  is urged in the direction of the coupled member  204  to rotate due to the inertial force. 
     During the rotation due to the inertial force, the coupling member  202  has a rotary speed which is slower than the rotary speed during the rotation driven by the rotary driver  206 . Accordingly, compared with the case where the coupling member  202  rotates by the driving of the rotary driver  206 , the coupling member  202  easily engages to the coupled member  204  in the case where the coupling member  202  rotates due to the inertial force. That is, the coupling portion and surrounding components thereof are configured so as to avoid a situation that the coupling member  202  rotates with the coupling projected part  202   a  and the coupled projected part  204   a  abutting together at the surfaces facing in the rotary axis direction of both the coupling member  202  and the coupled member  204 , i.e. an idling. 
     Next, the operation in the mounting of the image forming unit  130  will be described below. 
       FIG. 7  illustrates a flowchart of the operation executed by the controller  14  when the image forming unit  130  is mounted (S 10 ). 
     In a step  102  (S 102 ), the controller  14  receives the determination, whether the open-close covers  18   a  and  18   b  close, from the interlock switch  20 , and then waits until the open-close covers  18   a  and  18   b  close. When the open-close covers  18   a  and  18   b  close, the processing is advanced to a step  104  (S 104 ). 
     In the step  104  (S 104 ), the controller  14  turns the switch  142  on. Thereby, the rotary driver  206  drives to allow the coupling member  202  to rotate (an initial rotation). 
     In a step  106  (S 106 ), the controller  14  determines the elapse of a certain period of time, and then waits until a certain period of time elapses. When the controller  14  determines that a certain period of time elapses, the processing is advanced to a step  108  (S 108 ). The certain period of time means a time while, for instance, the coupling member  202  rotates several times (around 1 to 5 times) by the rotary driver  206 . 
     In the step  108  (S 108 ), the controller  14  turns the switch  142  off. Thereby, the rotary driver  206  stops driving, and the coupling member  202  rotates due to the inertial force. 
     In a step  110  (S 110 ), the controller  14  determines the elapse of a certain period of time, and waits until the predetermined time elapses. After the determination that the predetermined time elapses, the processing is advanced to a step  112  (S 112 ). The predetermined time in the step  110  means a stopping time until, for instance, the coupling member  202  stops rotating due to the inertial force. 
     In the step  112  (S 112 ), the controller  14  turns the switch  142  on again. Thereby, the rotary driver  206  drives to allow the coupling member  202  to rotate (re-rotation). 
     In a step  114  (S 114 ), the controller  14  receives the determination from the intermediate transfer sensor  100  whether or not the intermediate transfer member  84  rotates. When the determination that the intermediate transfer member  84  is rotating has been done, that is, when the coupling member  202  and the coupled member  204  connect together, the operation (S 10 ) of the controller  14  in the mounting of the image forming unit  130  normally exits. 
     On the other hand, when the determination that the intermediate transfer member  84  is rotating has not been done, that is, when the coupling member  202  and the coupled member  204  loosely connect, the controller  14  make the touch panel  132  to display the notice of the error with the UI  204 . 
     The exemplary embodiment herein described is configured so that the controller  14  allows the rotary driver  206  to drive in the manner where the determination that the open-close covers  18   a  and  18   b  close is detected by the interlock switch  20  (S 102 ), but not to be limited to the configuration, the driving in the step  104  (S 104 ) may start by operating the touch panel  132  by an operator. 
     Second Exemplary Embodiment 
     Next, the second exemplary embodiment will be described below. 
       FIG. 8  illustrates a flowchart of the operation executed by the controller  14  (S 20 ) when the image forming unit  130  is mounted. In the second exemplary embodiment, the processing in a step  214  is executed after the processing in the above steps S 102  to S 112 . 
     In the step  214  (S 214 ), the controller  14  receives the determination from the intermediate transfer sensor  100  whether or not the intermediate transfer member  84  rotates. When the intermediate transfer member  84  is rotating, that is, when the coupling member  202  and the coupled member  204  connect together, the operation (S 20 ) by the controller  14  in the mounting of the image forming unit  130  normally exits. 
     On the other hand, when the intermediate transfer member  84  is not rotating, that is, when the coupling member  202  and the coupled member  204  loosely connect, the processing is returned to the step  104  (S 104 ). 
     In the second exemplary embodiment, the processing in the steps  104  to  112  (S 104 -S 112 ) and the step  214  (S 214 ) repeat until the determination that the intermediate transfer member  84  rotates has done, that is, until the coupling member  202  and the coupled member  204  connect together. 
     The foregoing description of the exemplary embodiment 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 modification and variations will be apparent to practitioners skilled in the art. The exemplary embodiment was 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 suites to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.