Patent Publication Number: US-9841715-B2

Title: Image forming apparatus, method for controlling image forming apparatus

Description:
INCORPORATION BY REFERENCE 
     This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2015-221967 filed on Nov. 12, 2015, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to an image forming apparatus and a method for controlling an image forming apparatus. 
     An image forming apparatus may include a main body portion and a post-processing device, wherein the main body portion includes an image forming portion and the post-processing device is connected to the main body portion. The post-processing device includes a post-processing portion configured to perform a work on a plurality of overlapped sheets collectively. The post-processing portion is, for example, a staple portion configured to perform a sheet binding work to bind a plurality of sheets, or a sheet folding portion configured to perform a sheet folding work to fold a plurality of sheets. 
     When the post-processing portion executes a process, the image forming portion and a sheet conveying portion that conveys sheets execute a continuous printing process in which images of a plurality of pages are formed on a plurality of sheets. With this process, the plurality of sheets with the images formed thereon are temporarily collected on an intermediate tray in an overlapped state. The post-processing portion executes the post-processing on the plurality of sheets collected on the intermediate tray. 
     SUMMARY 
     An image forming apparatus according to an aspect of the present disclosure includes a sheet supplying portion, a pre-processing portion, an intermediate tray, a discharge tray, a post-processing portion, a jam detecting portion, a discontinuation control portion, a dummy feed control portion, a supplementary printing control portion, and a post-supplementary-process control portion. In the sheet supplying portion, sheets are set. The pre-processing portion includes a sheet conveying portion configured to convey the sheets and an image forming portion configured to form images on the sheets. The pre-processing portion is configured to execute a continuous printing process in which a plurality of pages of images are formed on a plurality of sheets while the plurality of sheets are conveyed one by one from the sheet supplying portion along a predetermined conveyance path. The intermediate tray is provided on a downstream side of the conveyance path in a conveyance direction, and configured to temporarily store the plurality of sheets with the images formed thereon. The discharge tray is provided on a downstream side of the intermediate tray in the conveyance direction, and configured to receive the plurality of sheets. The post-processing portion is configured to execute a post-processing in which to perform a predetermined work collectively on the plurality of sheets collected on the intermediate tray, and to discharge a bundle of sheets on which the work was performed, from the intermediate tray to the discharge tray. The jam detecting portion is configured to detect a paper jam of one or more sheets that has occurred in the conveyance path. The discontinuation control portion is configured to, when the paper jam is detected while the continuous printing process is performed by the pre-processing portion, discontinue the continuous printing process until the paper jam is solved. The dummy feed control portion is configured to, after the paper jam is solved, cause the pre-processing portion to execute a dummy feed process in which sheets as many as a predetermined dummy feed number are conveyed from the sheet supplying portion to the intermediate tray, without formation of images on the sheets. The supplementary printing control portion is configured to, after the dummy feed process, cause the pre-processing portion to execute a supplementary printing process in which images are formed on one or more sheets conveyed from the sheet supplying portion, the images being images of remaining pages that are obtained by excluding pages corresponding to the dummy feed number of sheets starting from a beginning page, from all pages that are a target of the continuous printing process. The post-supplementary-process control portion is configured to, after the supplementary printing process, cause the post-processing portion to execute the post-processing. 
     A method for controlling an image forming apparatus according to another aspect of the present disclosure is a method for controlling an image forming apparatus that includes the sheet supplying portion, the pre-processing portion, the intermediate tray, the discharge tray, the post-processing portion, and the jam detecting portion. The method includes the following steps. One of the steps is a step of, when a paper jam is detected while the continuous printing process is performed by the pre-processing portion, discontinuing the continuous printing process until the paper jam is solved. Another one of the steps is a step of, after the paper jam is solved, causing the pre-processing portion to execute a dummy feed process in which a predetermined dummy feed number of sheets are conveyed from the sheet supplying portion to the intermediate tray, without formation of images on the sheets. A further one of the steps is a step of, after the dummy feed process, causing the pre-processing portion to execute a supplementary printing process in which images are formed on one or more sheets conveyed from the sheet supplying portion, the images being images of remaining pages that are obtained by excluding pages corresponding to the dummy feed number of sheets starting from a beginning page, from all pages that are a target of the continuous printing process. A further one of the steps is a step of, after the supplementary printing process, causing the post-processing portion to execute the post-processing. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description with reference where appropriate to the accompanying drawings. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a configuration diagram of an image forming apparatus according to an embodiment of the present disclosure. 
         FIG. 2  is a configuration diagram of an image reading portion and an image forming portion of the image forming apparatus according to the embodiment of the present disclosure. 
         FIG. 3  is a configuration diagram of a post-processing portion of the image forming apparatus according to the embodiment of the present disclosure. 
         FIG. 4  is a block diagram of control-related equipment of the image forming apparatus according to the embodiment of the present disclosure. 
         FIG. 5  is a flowchart showing an example of procedures of a copy-unit control in the image forming apparatus according to the embodiment of the present disclosure. 
         FIG. 6  is a flowchart showing an example of procedures of a paper jam control in the image forming apparatus according to the embodiment of the present disclosure. 
         FIG. 7  is a flowchart showing an example of procedures of a post-jam-solution control in the image forming apparatus according to the embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following describes an embodiment of the present disclosure with reference to the attached drawings. It should be noted that the following embodiment is an example of a specific embodiment of the present disclosure and should not limit the technical scope of the present disclosure. 
     [Configuration of Image Forming Apparatus  10 ] 
     First, a description is given of a configuration of an image forming apparatus  10  according to the embodiment with reference to  FIG. 1  to  FIG. 4 . The image forming apparatus  10  shown in  FIG. 1  is a multifunction peripheral including an image reading function, an image forming function, and a post-processing function. 
     The image forming apparatus  10  includes an image reading portion  1 , a main body portion  2 , and a post-processing portion  5 . The main body portion  2  includes a sheet supplying portion  30 , a sheet conveying portion  3 , and an image forming portion  40 . The image forming apparatus  10  also includes a control portion  8 , an operation display portion  80 , and a plurality of sheet sensors  800  (see  FIG. 2 ). It is noted that the image forming apparatus  10  may not include the image reading portion  1 . 
     [Image Reading Portion  1  and Main Body Portion  2 ] 
     The image reading portion  1  is a device that reads an image from a document sheet. When the image forming apparatus  10  executes a copy job, the image forming portion  40  forms an image on a sheet  9  based on image data of the document sheet, wherein the image data is output from the image reading portion  1 . In addition, when executing a print job received from a terminal (not shown), the image forming portion  40  forms an image on the sheet  9  based on the print job. 
     The sheet supplying portion  30  is a cassette or a tray on which a plurality of sheets  9  are set. In the present embodiment, the image forming apparatus  10  includes a plurality of sheet supplying portions  30 . The plurality of sheet supplying portions  30  include a sheet cassette  30   a  and a manual feed tray  30   b . The sheet  9  is a sheet-like image formation medium such as a sheet of paper. 
     The sheet conveying portion  3  is a mechanism for conveying, along conveyance paths  300  to  305  provided in the apparatus, sheets  9  fed one by one from the sheet supplying portions  30 . The sheet conveying portion  3  is provided in the main body portion  2  and the post-processing portion  5 . 
     The sheet conveying portion  3  includes a plurality of pairs of conveyance rollers  32  and a plurality of route switching portions  33 , wherein the pairs of conveyance rollers  32  convey the sheet  9 , and the route switching portions  33  change, by pivoting, directions in which the sheet  9  is guided. 
     For example, the sheet conveying portion  3  can convey the sheet  9  from the sheet supplying portion  30  along a main conveyance path  300  and a first conveyance path  301 , and discharge it to a first discharge tray  311  (see  FIG. 2 ). 
     In addition, the sheet conveying portion  3  can convey the sheet  9  from the sheet supplying portion  30  along the main conveyance path  300 , a second conveyance path  302  and a third conveyance path  303 , to an intermediate tray  60  in the post-processing portion  5  (see  FIG. 2  and  FIG. 3 ). It is noted that the third conveyance path  303  and a part of the second conveyance path  302  are formed in the post-processing portion  5 . 
     In addition, the sheet conveying portion  3  can convey the sheet  9  from the sheet supplying portion  30  along the main conveyance path  300  and the second conveyance path  302 , to a fourth conveyance path  304  or a fifth conveyance path  305  (see  FIG. 2  and  FIG. 3 ). 
     The image forming portion  40  shown in  FIG. 2  executes an image forming process by the electrophotography. In this case, the image forming portion  40  includes a drum-like photoconductor  41 , a charging portion  42 , a laser scan unit  43 , a developing portion  44 , a transferring portion  45 , and a fixing portion  46 . It is noted that the image forming portion  40  may perform the image forming process by another method such as the ink jet method. 
     The image forming portion  40  forms an image on the surface of the sheet  9  while the sheet  9  is moving along the main conveyance path  300 . Hereinafter, the sheet conveying portion  3  and the image forming portion  40  are referred to as a pre-processing portion  4 . 
     [Post-Processing Portion  5 ] 
     The post-processing portion  5  is configured to perform processing on sheets  9  that are conveyed from the main body portion  2  after image formation thereon. The post-processing portion  5  includes the intermediate tray  60  on the downstream side of the third conveyance path  303  in the conveyance direction such that a plurality of sheets  9  with images formed thereon are temporarily collected on the intermediate tray  60 . The intermediate tray  60  is formed in an inclined state with respect to the horizontal direction. A second discharge tray  312  is provided on the downstream side of the intermediate tray  60  in the conveyance direction. 
     In the example shown in  FIG. 3 , the post-processing portion  5  includes a sheet binding portion  6 . The sheet binding portion  6  includes a stapling portion  61 , a sheet aligning portion  62 , and a pair of discharge rollers  63 . 
     The sheet binding portion  6  executes a sheet binding work to bind a plurality of sheets  9  collected on the intermediate tray  60 . For example, the sheet binding portion  6  is a stapler that binds the plurality of sheets  9  by a metal staple or the like. 
     The pair of discharge rollers  63  are configured to discharge a bundle of sheets  9  that have been bound together by the sheet binding work, from the intermediate tray  60  to the second discharge tray  312 . The pair of discharge rollers  63  are switched between a closed state and an open state by one of the pair of discharge rollers  63  being displaced, wherein in the closed state, the two rollers are located close to each other, and in the open state, the two rollers are separate from each other. 
     In the present embodiment, the post-processing portion  5  includes a plurality of second discharge trays  312  on the downstream side of the intermediate tray  60  in the conveyance direction. The plurality of second discharge trays  312  are supported by a lifting and lowering mechanism  312   a  so as to be movable up and down. 
     The lifting and lowering mechanism  312   a  lifts and lowers the plurality of second discharge trays  312  all at once so that one of the plurality of second discharge trays  312  is disposed at a position where it can receive the sheets  9  discharged by the pair of discharge rollers  63 . This makes it possible to select, from among the plurality of second discharge trays  312 , a discharge destination of the sheets  9  from the intermediate tray  60 . 
     When a sheet  9  is conveyed from the third conveyance path  303  to the intermediate tray  60 , the sheet  9  falls on the intermediate tray  60  while a part of the front side of the sheet  9  goes into between the pair of discharge rollers  63  in the open state. 
     The sheet aligning portion  62  aligns the lower edge of the sheet  9  with the lower edge of the intermediate tray  60  by pivoting while contacting the sheet  9  that fell on the intermediate tray  60 . The sheet aligning portion  62  pivots at a position facing the intermediate tray  60 . The sheet aligning portion  62  is, for example, an elastic member such as a plate-like rubber member. 
     The pair of discharge rollers  63  move from the open state to the closed state in a state where one or more sheets  9  are present on the intermediate tray  60 , and then rotate such that the one or more sheets  9  are discharged from the intermediate tray  60  onto the second discharge tray  312 . 
     In the following description, a sheet binding process refers to a process in which the sheet binding portion  6  performs the sheet binding work to collectively bind a plurality of sheets  9  stored on the intermediate tray  60 , and the pair of discharge rollers  63  discharge a bundle of sheets  9  that have been bound together by the sheet binding work, from the intermediate tray  60  to the second discharge tray  312 . It is noted that the sheet binding process is an example of the post-processing, and the sheet binding portion  6  is an example of the post-processing portion. 
     When the sheet binding portion  6  executes the sheet binding process, the pre-processing portion  4  executes a continuous printing process. In the continuous printing process, a plurality of sheets  9  are conveyed one by one from the sheet supplying portion  30  along the main conveyance path  300 , the second conveyance path  302  and the third conveyance path  303 , and a plurality of pages of images are formed on the plurality of sheets  9 . 
     In the following description, the number of sheets  9  that are processed in one continuous printing process is referred to as a unit number of sheets. When the unit number of sheets  9  are collected on the intermediate tray  60 , the sheet binding portion  6  performs the sheet binding process. 
     In addition, the pre-processing portion  4  may execute a copy-unit printing process in which the continuous printing process is repeated as many times as a specified number of copies that has been set in advance. In this case, the sheet binding portion  6  executes a copy-unit sheet binding process. In the copy-unit sheet binding process, the sheet binding process is performed each time the unit number of sheets  9  are collected on the intermediate tray  60  in the copy-unit printing process. It is noted that the copy-unit sheet binding process is an example of the copy-unit post-processing. 
     In the example shown in  FIG. 3 , the post-processing portion  5  also includes a punching portion  5   x  and a sheet folding portion  7 . The punching portion  5   x  performs a punching work to form a punching hole in each sheet  9  that is being conveyed in the second conveyance path  302 . Another intermediate tray  70  is provided on the downstream side of the fifth conveyance path  305 , and a third discharge tray  313  is provided on the downstream side of the intermediate tray  70  in the conveyance direction. 
     The sheet folding portion  7  performs a sheet folding work to fold a plurality of sheets  9  collected on the intermediate tray  70 , and discharge a bundle of sheets  9  that have been folded by the sheet folding work to the third discharge tray  313 . The sheet folding portion  7  includes a blade  71 , a pair of sheet folding rollers  72 , and a pair of discharge rollers  73 . The blade  71  pushes a plurality of overlapped sheets  9  into a nip portion of the pair of sheet folding rollers  72 , and the pair of sheet folding rollers  72  form a fold on the sheets  9 . The pair of discharge rollers  73  discharge a bundle of sheets  9  that have been passed through the pair of sheet folding rollers  72  onto the third discharge tray  313 . 
     The plurality of sheet sensors  800  are configured to detect each sheet  9  that is being conveyed along the conveyance paths. The sheet sensors  800  may be, for example, reflection-type photosensors or transmission-type photosensors. 
     The plurality of sheet sensors  800  are disposed at a plurality of locations along a route from the sheet supplying portion  30  to the intermediate tray  60  via the main conveyance path  300 , the second conveyance path  302  and the third conveyance path  303 . In the example shown in  FIG. 2  and  FIG. 3 , the sheet sensors  800  are provided also in the first conveyance path  301 , the fourth conveyance path  304  and the fifth conveyance path  305 . 
     The sheet sensors  800  can detect a paper jam of one or more sheets  9 . In addition, at least one sheet sensor  800  is provided in the third conveyance path  303 . The third conveyance path  303  is located at a position where a sheet  9  passes through before going above the intermediate tray  60 . The sheet sensor  800  of the third conveyance path  303  can also detect the number of sheets  9  collected on the intermediate tray  60 . 
     The operation display portion  80  includes an operation portion and a display portion, wherein the operation portion receives operations of inputting information and the display portion displays information. For example, the operation portion and the display portion may be a touch panel unit that includes a touch panel and a display panel on which the touch panel is formed. 
     The control portion  8  controls the image reading portion  1 , the pre-processing portion  4 , the post-processing portion  5  and the operation display portion  80 . Furthermore, the control portion  8  performs various types of determination processes and calculation processes based on detection results of the sheet sensors  800 . 
     As one example, the control portion  8  may include a MPU (Micro Processor Unit) and a RAM (Random Access Memory), wherein the MPU executes programs stored in a nonvolatile, computer-readable storage portion (not shown). In addition, the control portion  8  may be a combination of one or more of the MPU, an ASIC (Application Specific Integrated Circuit), and a DSP (Digital Signal Porcessor). 
     In the control portion  8 , an UI control portion  81  controls the operation display portion  80 . In addition, a paper jam determining portion  82  of the control portion  8  determines whether or not a paper jam has occurred and the location of the paper jam, based on a successive detection time period of a sheet  9  by the sheet sensors  800 . 
     Specifically, when a certain sheet sensor  800  detects a sheet  9  successively for over a predetermined upper-limit time period, the paper jam determining portion  82  determines that a paper jam has occurred at a position where the sheet sensor  800  is located. 
     The plurality of sheet sensors  800  and the paper jam determining portion  82  are an example of the paper jam detecting portion that detects a paper jam of one or more sheets  9  in the conveyance paths  300  to  305 . 
     In addition, in the control portion  8 , a progress determining portion  83  determines a progress state of the continuous printing process and the copy-unit printing process. As one example, the progress determining portion  83  determines the number of sheets  9  collected on the intermediate tray  60  by counting the number of times that the sheet sensor  800  of the third conveyance path  303  detected a passage of a sheet  9  after the pair of discharge rollers  63  had last discharged sheets  9 . 
     The count value of the number of times that the sheet sensor  800  of the third conveyance path  303  detected a passage of a sheet  9 , is reset each time it reaches the unit number of sheets. Each time the count value reaches the unit number of sheets, the progress determining portion  83  outputs an event for the operation of the pair of discharge rollers  63 . 
     Furthermore, while the copy-unit printing process and the copy-unit sheet binding process are executed, each time the count value reaches the unit number of sheets, the progress determining portion  83  counts up the number of copies that were bound together by the sheet binding process. This enables the progress determining portion  83  to calculate the number of copies on which the sheet binding process was completed. 
     In addition, in the control portion  8 : a pre-processing control portion  84  controls the pre-processing portion  4  that includes the sheet conveying portion  3  and the image forming portion  40 ; and a post-processing control portion  85  controls the sheet binding portion  6 , the punching portion  5   x  and the sheet folding portion  7 . 
     Meanwhile, in general, when a paper jam of one or more sheets  9  is detected while the continuous printing process is executed, the continuous printing process is discontinued. In a conventional image forming apparatus, after the user removes all of the sheets  9  from the apparatus and the paper jam is solved, the continuous printing process is performed again from the beginning. 
     However, there may be a case where one or more sheets  9  with images formed thereon have been collected on the intermediate tray  60  before the continuous printing process is discontinued. In this case, if both the sheets  9  involved in the paper jam and the sheets  9  collected on the intermediate tray  60  are discarded, the process resumed after the paper jam solution consumes sheets  9 , developer and time wastefully. 
     In the image forming apparatus  10 , too, when a paper jam occurs, the continuous printing process is discontinued and the post-processing that is performed on a plurality of sheets  9  collected on the intermediate tray  60  during the continuous printing process, is also discontinued. However, with the adoption of the image forming apparatus  10 , a control described below is executed, and it is possible to prevent the process resumed after the paper jam solution from consuming sheets  9 , developer and time wastefully. 
     [Copy-Unit Control] 
     Next, an example of the procedures of a copy-unit control executed by the control portion  8  is described with reference to the flowchart shown in  FIG. 5 . In the following description, S 101 , S 102 , . . . are identification signs representing the steps executed by the control portion  8 . 
     &lt;Step S 101 &gt; 
     When a start event for the copy-unit printing process and the copy-unit sheet binding process occurs, the control portion  8  starts the copy-unit control. The start event is that a predetermined start operation is performed on the operation portion of the operation display portion  80 , or that a job is received from an external apparatus via a communication interface (not shown). 
     The copy-unit control is a control in which the pre-processing control portion  84  causes the pre-processing portion  4  to execute the copy-unit printing process, and the post-processing control portion  85  causes the sheet binding portion  6  to execute the copy-unit sheet binding process. It is noted that the pre-processing control portion  84  and the post-processing control portion  85  that execute the copy-unit control are an example of the copy-unit control portion. 
     &lt;Step S 102 &gt; 
     While the copy-unit control is performed, the progress determining portion  83  determines a progress state of the continuous printing process and the copy-unit printing process. 
     &lt;Step S 103 &gt; 
     Furthermore, while the copy-unit control is performed, the paper jam determining portion  82  determines whether or not a paper jam has occurred. 
     &lt;Step S 104 &gt; 
     When the progress determining portion  83  determines that the copy-unit printing process and the copy-unit sheet binding process have been completed without occurrence of a paper jam, the pre-processing control portion  84  and the post-processing control portion  85  end the copy-unit control. 
     &lt;Step S 105 &gt; 
     On the other hand, when a paper jam is detected while the continuous printing process is performed during the copy-unit printing process, the control portion  8  executes a paper jam control described below. Thereafter, the control portion  8  ends the copy-unit control. 
     [Paper Jam Control] 
     Next, an example of the procedures of a paper jam control executed by the control portion  8  is described with reference to the flowchart shown in  FIG. 6 . In the following description, S 201 , S 202 , . . . are identification signs representing the steps executed by the control portion  8 . 
     &lt;Step S 201 &gt; 
     When a paper jam is detected while the continuous printing process is performed, the pre-processing control portion  84  discontinues the continuous printing process that has been performed by the pre-processing portion  4 , until the paper jam is solved. The pre-processing control portion  84  that executes the process of step S 201  is an example of the discontinuation control portion. 
     It is noted that if the unit number of sheets  9  have been collected on the intermediate tray  60  when the paper jam is detected, the post-processing control portion  85  causes the sheet binding process that has been started and is in the middle of the process, to be completed, or causes the sheet binding process that has not yet been started, to be started and completed. 
     &lt;Step S 202 &gt; 
     The UI control portion  81  outputs an error notification that represents a paper jam occurrence status, to the display portion of the operation display portion  80 . 
     &lt;Step S 203 &gt; 
     The progress determining portion  83  determines whether or not one or more sheets  9  less than the unit number of sheets are present in the intermediate tray  60 . It is noted that the number of sheets  9  that are present in the intermediate tray  60  in step S 203  is the number of sheets  9  that had been conveyed to the intermediate tray  60  during the continuous printing process before the process was discontinued. 
     When the progress determining portion  83  determines that no sheet  9  is present in the intermediate tray  60 , steps S 204  and S 205  are skipped, and the process moves to step S 206 . 
     &lt;Step S 204 &gt; 
     When, in step S 203 , the progress determining portion  83  determines that one or more sheets  9  less than the unit number of sheets are present in the intermediate tray  60 , the post-processing control portion  85  executes a remaining sheet discharge control. The remaining sheet discharge control is a control to cause the sheet binding portion  6  not to perform the sheet binding process, but to discharge the sheets  9  remaining in the intermediate tray  60 , to the second discharge tray  312 . 
     It is noted that the remaining sheet discharge control (S 204 ) is executed at least before the next step S 205  (a dummy feed process) is executed. The post-processing control portion  85  that executes the process of step S 204  is an example of the remaining sheet discharge control portion. 
     On the sheets  9  discharged in step S 204 , images of pages starting from the starting page, among all pages that are the target of the continuous printing process, have been formed. The sheets  9  discharged in step S 204  are not discarded, but used effectively later. The use form is described below. 
     &lt;Step S 205 &gt; 
     The progress determining portion  83  sets, as a dummy feed number, the number of sheets  9  that were determined to be present in the intermediate tray  60  in step S 203 . The dummy feed number is referred to in step S 306  of  FIG. 7  described below. The progress determining portion  83  that executes the process of step S 205  is an example of the dummy feed number automatic setting portion. 
     When the unit number of sheets is five, for example, and a paper jam occurs after the second sheet  9  is conveyed and before the third sheet  9  is conveyed to the intermediate tray  60  in the continuous printing process, the dummy feed number is set to two. 
     &lt;Step S 206 &gt; 
     The progress determining portion  83  calculates the succeeding number of copies. The succeeding number of copies is obtained by subtracting, from the specified number of copies, the number of copies that is obtained by adding one to the number of copies on which the sheet binding process had been completed before the continuous printing process was discontinued. 
     The succeeding number of copies is referred to in step S 301  of  FIG. 7  that is described below. It is noted that the progress determining portion  83  that executes the process of step S 206  is an example of the succeeding copy number calculating portion. 
     Suppose that the specified number of copies is four, and a paper jam occurs after binding of two copies of sheets have been completed and before the unit number of sheets  9  are collected on the intermediate tray  60  during the copy-unit sheet binding process, then the succeeding number of copies is calculated as one from (4−(2+1)). 
     &lt;Step S 207 &gt; 
     The paper jam determining portion  82  determines whether or not the paper jam has been solved. The discontinuation of the continuous printing process is maintained until the paper jam determining portion  82  determines that the paper jam has been solved. 
     It is noted that the paper jam is solved when the user remove the sheets  9  that were involved in the paper jam, from the conveyance paths  300  to  305 . 
     &lt;Step S 208 &gt; 
     When the paper jam determining portion  82  determines that the paper jam has been solved, the control portion  8  executes a post-jam-solution control. With the execution of the post-jam-solution control, the paper jam control is completed. 
     [Post-Jam-Solution Control] 
     Next, an example of the procedures of the post-jam-solution control executed by the control portion  8  is described with reference to the flowchart shown in  FIG. 7 . In the following description, S 301 , S 302 , . . . are identification signs representing the steps executed by the control portion  8 . 
     &lt;Step S 301 &gt; 
     After the paper jam is solved, the control portion  8  executes a succeeding control. In the succeeding control, the pre-processing control portion  84  and the post-processing control portion  85  cause the pre-processing portion  4  and the sheet binding portion  6  to perform the copy-unit printing process and the copy-unit sheet binding process on the succeeding number of copies calculated in step S 206 . 
     In other words, during step S 301 , the pre-processing control portion  84  and the post-processing control portion  85  cause the pre-processing portion  4  and the sheet binding portion  6  to perform the copy-unit printing process and the copy-unit sheet binding process, with the succeeding number of copies being set as the specified number of copies. 
     It is noted that the pre-processing control portion  84  and the post-processing control portion  85  that execute the process of step S 301  are an example of the succeeding control portion. 
     As explained above, when the specified number of copies is four, and a paper jam occurs after binding of two copies of sheets have been completed and before the unit number of sheets  9  are collected on the intermediate tray  60  during the copy-unit sheet binding process, the succeeding number of copies is calculated as one. In this case, the copy-unit printing process and the copy-unit sheet binding process are performed, with 1 (one) being set as the specified number of copies. 
     During the succeeding control performed in step S 301 , the post-processing control portion  85  causes the sheet binding portion  6  to discharge a bundle of sheets  9  to a second discharge tray  312  that is different from the second discharge tray  312  to which the sheets  9  were discharged during the remaining sheet discharge control (S 204  of  FIG. 6 ). 
     That is, the post-processing control portion  85  switches between the second discharge trays  312  as the discharge destinations, by controlling the lifting and lowering mechanism  312   a , and then causes the sheet binding portion  6  to execute the process of discharging the bundle of sheets  9 . 
     For example, there may be a case where, during the copy-unit control (S 101  of  FIG. 5 ) and the remaining sheet discharge control (S 204  of  FIG. 6 ), sheets  9  are discharged from the intermediate tray  60  to a same second discharge tray  312 . When the second discharge tray  312  in that case is the first-tier tray, sheets are discharged from the intermediate tray  60  to the second discharge tray  312  of the second-tier during the succeeding control (S 301 ). 
     In addition, there may be a case where, during the copy-unit control (S 101  of  FIG. 5 ), sheets  9  are discharged from the intermediate tray  60  to the second discharge tray  312  of the first-tier, and during the remaining sheet discharge control (S 204  of  FIG. 6 ), sheets  9  are discharged from the intermediate tray  60  to the second discharge tray  312  of the second-tier. In this case, during the succeeding control (S 301 ), sheets  9  may be discharged from the intermediate tray  60  to the second discharge tray  312  of the first-tier. 
     This prevents the sheets  9  discharged in step S 204  on which the sheet binding process has not been performed, from being embedded under bundles of sheets  9  that are discharged later after being bound together by the sheet binding process. 
     &lt;Step S 302 &gt; 
     While the succeeding control is performed, the progress determining portion  83  determines a progress state of the continuous printing process and the copy-unit printing process. 
     &lt;Step S 303 &gt; 
     While the succeeding control is performed, the paper jam determining portion  82  determines whether or not a paper jam has occurred. 
     &lt;Step S 304 &gt; 
     When the progress determining portion  83  determines that the succeeding control has been completed without occurrence of a paper jam, the control portion  8  executes the processes of steps S 306  to S 308  that are described below. It is noted that the succeeding control ends when the copy-unit printing process and the copy-unit sheet binding process end. 
     During a period from the start of the copy-unit control (S 101 ) to the end of the succeeding control (S 301 ), bundles of sheets  9  that have each been bound together by the sheet binding process are discharged to the second discharge tray  312 , the bundles of sheets  9  corresponding to the number of copies that is obtained by subtracting one from the specified number of copies. 
     In addition, the sheets  9  discharged in step S 204  of  FIG. 6  are set in the sheet supplying portion  30  by the user at least until the succeeding control ends. 
     In the present embodiment, the sheets  9  discharged in S 204  are set in a sheet supplying portion  30  that is different from a sheet supplying portion  30  used in the continuous printing process (S 101 , S 301 ) and a supplementary printing process (S 307 ) that is described below. More specifically, the sheet cassette  30   a  is used in the continuous printing process (S 101 , S 301 ) and the supplementary printing process (S 307 ) that is described below, and the sheets  9  discharged in step S 204  are set in the manual feed tray  30   b.    
     &lt;Step S 305 &gt; 
     On the other hand, when a paper jam is detected in the middle of the continuous printing process in the copy-unit printing process, the control portion  8  executes the paper jam control (see  FIG. 6 ). This allows the succeeding control to be discontinued (step S 201  of  FIG. 6 ). After the paper jam control, the control portion  8  ends the post-jam-solution control. 
     It is noted that after the post-jam-solution control ends, the processes from step S 301  are executed again. 
     &lt;Step S 306 &gt; 
     When the succeeding control ends after the paper jam is solved, the pre-processing control portion  84  causes the pre-processing portion  4  to execute the dummy feed process. In the dummy feed process, sheets  9  as many as a predetermined dummy feed number are conveyed from the sheet supplying portion  30  to the intermediate tray  60 , without images being formed on the sheets  9 . It is noted that the pre-processing control portion  84  that performs the process of step S 306  is an example of the dummy feed control portion. 
     In the present embodiment, the pre-processing control portion  84  of step S 306  causes the pre-processing portion  4  to convey sheets  9  from the manual feed tray  30   b . It is noted that, as described above, in the continuous printing process (S 101 , S 301 ) and the supplementary printing process (S 307 ) described below, sheets  9  are conveyed from the sheet cassette  30   a.    
     &lt;Step S 307 &gt; 
     After the dummy feed process, the pre-processing control portion  84  causes the pre-processing portion  4  to execute the supplementary printing process. In the supplementary printing process, images are formed on one or more sheets  9  conveyed from the sheet supplying portion  30 , the images formed being images of remaining pages that are obtained by excluding pages corresponding to the dummy feed number of sheets  9  starting from the beginning page, from all pages that are the target of the continuous printing process. 
     In the supplementary printing process, sheets  9  are conveyed from the sheet cassette  30   a  that is different from the manual feed tray  30   b  from which sheets  9  are supplied in the dummy feed process (S 306 ). With this configuration, it is possible to avoid such a problematic situation where sheets  9  used in the supplementary printing process are smeared by contacting sheets  9  on which images have been formed. It is noted that the pre-processing control portion  84  that executes the process of step S 307  is an example of the supplementary printing control portion. 
     Suppose that the unit number of sheets is five, for example, and the dummy feed number is two. In that case, in the supplementary printing process, images are formed on three sheets  9  conveyed from the sheet cassette  30   a , wherein the images formed are images of remaining pages obtained by excluding pages corresponding to two sheets  9  starting from the beginning sheet  9  from all pages corresponding to the unit number of sheets, five. 
     At the time when the processes of steps S 306  and S 307  are completed, the unit number of sheets  9  have been collected on the intermediate tray  60 . More specifically, first, one or more sheets  9  have been collected on the intermediate tray  60  (step S 306 ) when the continuous printing process is discontinued and on which images of pages starting from the beginning page have been formed. In addition, one or more sheets  9  are collected on the intermediate tray  60  on which images of succeeding pages have been formed by the supplementary printing process (S 307 ). 
     &lt;Step S 308 &gt; 
     After the supplementary printing process, the post-processing control portion  85  causes the sheet binding portion  6  to execute the sheet binding process. This allows a bundle of sheets  9  which is the last copy of the sheet binding process, to be discharged to the second discharge tray  312 . 
     With the end of step S 305  or step S 308 , the post-jam-solution control ends. It is noted that the post-processing control portion  85  that executes the process of step S 308  is an example of the post-supplementary-process control portion. 
     It is noted that the pre-processing control portion  84  and the post-processing control portion  85  perform the succeeding control (S 301 ) to the pre-processing portion  4  and the sheet binding portion  6  after the paper jam is solved and before the dummy feed process (S 306 ) is executed. 
     With the adoption of the image forming apparatus  10 , if the continuous printing process is discontinued by an occurrence of a paper jam, sheets  9  with images formed thereon collected on the intermediate tray  60  are effectively used in a process that is resumed after the paper jam is solved (S 306 ). As a result, compared to a case where the sheets  9  are discarded from the intermediate tray  60 , it is possible to eliminate the wasteful consumption of sheets  9 , developer and time. 
     The execution of the remaining sheet discharge control (S 204 ) makes it possible to eliminate the effort and time of the user to take out the sheets  9  with images formed thereon from the intermediate tray  60 . 
     Application Examples 
     According to the image reading portion  10  described above, the dummy feed number is automatically set by the progress determining portion  83  (S 205 ). On the other hand, the dummy feed number may be set by an operation of the user. In this case, the user confirms the number of sheets  9  that had been discharged to the second discharge tray  312  when a paper jam occurred, and performs an operation of inputting that number. 
     As one example, the UI control portion  81  may set the dummy feed number in accordance with an operation performed on the operation portion of the operation display portion  80 . The UI control portion  81  that executes this process is an example of the dummy feed number manual setting portion. 
     For example, the setting process may be executed before the process of step S 301  or before the process of step S 304 . 
     In addition, in the image forming apparatus  10 , the remaining sheet discharge control (S 204  of  FIG. 6 ) may be omitted. In this case, the user takes out the sheets  9  with images formed thereon from the intermediate tray  60  when the user performs a work of solving the paper jam. The sheets  9  taken out are set in the sheet supplying portion  30  before the dummy feed process (S 306  of  FIG. 7 ) is executed. 
     In addition, in the case where, for example, the image forming apparatus  10  includes only one second discharge tray  312 , there may be a case where the discharge destination of sheets  9  in the remaining sheet discharge control (S 204 ) and the discharge destination of sheets  9  in the succeeding control (S 301 ) are the same. 
     In addition, a same sheet supplying portion  30  may be used in the continuous printing process (S 101 , S 301 ) and the supplementary printing process (S 306  of  FIG. 7 ). For example, the manual feed tray  30   b  may be used in both processes. 
     In addition, in a case where the sheet folding portion  7  performs the sheet binding work on a plurality of sheets  9  collected on the intermediate tray  70  by the continuous printing process, the control shown in  FIG. 5  to  FIG. 7  may be applied. In this case, the sheet binding process is an example of the post-processing, and the sheet folding portion  7  is an example of the post-processing portion. 
     When, in the control shown in  FIG. 5  to  FIG. 7 , the process of the sheet folding portion  7  is adopted in place of the process of the sheet binding portion  6 , during the post-processing, the sheet folding work is performed on the plurality of sheets  9  collected on the intermediate tray  70 , and a bundle of sheets  9  folded by the sheet folding work are discharged to the third discharge tray  313 . In this case, the remaining sheet discharge control (S 204  of  FIG. 6 ) may be omitted. 
     It is noted that the image forming apparatus and the method for controlling the image forming apparatus of the present disclosure may be configured by freely combining, within the scope of claims, the above-described embodiments and application examples, or by modifying the embodiments and application examples or omitting a part thereof. 
     It is to be understood that the embodiments herein are illustrative and not restrictive, since the scope of the disclosure is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.