Abstract:
A sheet finishing apparatus including a sheet tray, a pair of jogging fences, and a case. The sheet tray stacks a plurality of sheets that have been sent from an image forming apparatus. The pair of jogging fences hold the sheets stacked in the sheet tray and jog the sheets in a transverse direction relative to a sheet transferring direction. The jogging fences are moved toward and away from each other. The case encloses the apparatus and includes a plate covering the sheet tray from an operator accessible side. The plate has an opening. When the pair of jogging fences is expanded to outward limits, one of the pair of jogging fences at the operator accessible side is passed by the plate through the opening and located at an outside position relative to the plate.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a method and apparatus for sheet finishing, and more particularly to a method and apparatus for sheet finishing which is capable of performing an effective jogging process.  
           [0003]    2. Description of the Related Art  
           [0004]    A sheet finishing apparatus is typically connected to or integral with an image forming apparatus. The sheet finishing apparatus receives a sheet having printed matter thereon from the image forming apparatus in order to provide the printed sheet with various post-image-forming processes including jogging, sorting, stapling, punching, etc. Such an apparatus normally has a complex structure with various mechanisms packed into a single body. As a result, such sheet finishing devices are typically ineffective in preventing paper jams and it is typically difficult to remove paper jams therefrom. Several attempts have been made to improve the paper jam handling of such sheet finishing devices.  
           [0005]    A published Japanese unexamined patent application, No. 7-187479 (1995), describes an apparatus that automatically ejects any sheet left in a jogger unit to an ejection tray and that unifies several post-image-forming functions such as jogging, stapling, ejection in one unit. The sheet left in the jogger unit, however, is normally not used and therefore it should not be mixed with other sheets in the ejection tray. In addition, the unified processes result in a complex mechanism and an increase in manufacturing costs.  
           [0006]    Another published Japanese unexamined patent application, No. 10-129921 (1998), describes an apparatus in which an external cover is unified with a drawing unit in order to decrease manufacturing costs of the apparatus. In fact, however, the cost is relatively high in comparison with an apparatus in which the unit does not include a drawing unit.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention provides a novel sheet finishing apparatus that is configured to be connected with an image forming apparatus. In one example, a novel sheet finishing apparatus includes a sheet tray, a pair of jogging fences, and a case. The sheet tray stacks a plurality of sheets that have been sent from an image forming apparatus. The pair of jogging fences holds the sheets stacked in the sheet tray and jog the sheets in a transverse direction relative to a sheet transferring direction. The pair of jogging fences is controlled to move inwards and outwards (i.e. toward and away from each other). The case encloses the apparatus and includes a plate covering the sheet tray from an operator accessible side. The plate has an opening. When the pair of jogging fences are expanded to outward limits, one of the pair of jogging fences at the operator accessible side is brought to pass by the plate through the opening and to locate at a position outside relative to the plate.  
           [0008]    When a sheet jam occurs in the sheet tray, the pair of jogging fences is expanded to have a predetermined distance away from each other.  
           [0009]    The pair of jogging fences preferably includes a first jogging member for jogging the sheets in a transverse direction relative to the sheet transferring direction and a second jogging member for jogging the sheets in a direction of a sheet thickness. When the pair of jogging fences is expanded to the predetermined distance away from each other, a closest distance between an edge of the second jogging member at a center side of the sheet tray and an edge of the opening of the plate is sufficient for a manual removal of the sheet jammed in the sheet tray.  
           [0010]    The present invention further provides a novel sheet finishing apparatus that is configured to be connected to an image forming apparatus. In one example, a novel sheet finishing apparatus includes a sheet tray, a pair of jogging fences, and a controller. The sheet tray stacks a plurality of sheets that have been sent from an image forming apparatus. The pair of jogging fences holds the sheets stacked in the sheet tray and jogs the sheets in a transverse direction relative to a sheet transferring direction. The controller controls the pair of jogging fences to move inwards and outwards. At a power-on time, the controller controls the pair of jogging fences to move a predetermined distance away from each other and to stop for a predetermined time period when a sheet is detected in the pair of jogging fences.  
           [0011]    When the pair of jogging fences are moved the predetermined distance away from each other, the pair of jogging fences may be positioned at the home position, or they may be positioned at or close to the most expanded position.  
           [0012]    The present invention further provides a novel method of sheet jogging. In one example, a novel method of sheet jogging includes the step of providing a power to a sheet finishing apparatus. The method includes a step of determining whether a sheet remains in a sheet tray for stacking a plurality of sheets that have been sent from an image forming apparatus. The method also includes a step of moving a jogging member a predetermined distance when a sheet is detected in the sheet tray, where the jogging member holds sheets stacked in the sheet tray and jogs the sheets in a transverse direction relative to a sheet transferring direction. The method further includes the step of stopping the jogging member for a predetermined time period.  
           [0013]    When the jogging member is moved the predetermined distance, the jogging member may be positioned at the home position, or may be positioned at or close to the most expanded position. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:  
         [0015]    [0015]FIG. 1 is a schematic cross-sectional view of a sheet finishing apparatus according to an embodiment of the present invention;  
         [0016]    [0016]FIG. 2 is a schematic view explaining a stapling tray of the sheet finishing apparatus of FIG. 1;  
         [0017]    [0017]FIG. 3 is a schematic view explaining how a sheet is transferred into a trailing edge fence;  
         [0018]    [0018]FIG. 4 is a perspective view depicting the trailing edge fence;  
         [0019]    [0019]FIG. 5 is a perspective view depicting a position at which a jogging fence is located outside a case of the apparatus of FIG. 1;  
         [0020]    [0020]FIG. 6 is a perspective view depicting a position at which the jogging fence is located inside the case of the apparatus of FIG. 1;  
         [0021]    [0021]FIG. 7 is a schematic view explaining an ejection of a stack of sheets by a lifting belt;  
         [0022]    [0022]FIG. 8 is a block diagram of a microcomputer circuit of the sheet finishing apparatus of FIG. 1;  
         [0023]    [0023]FIG. 9 is a schematic diagram for explaining a shift mechanism for shifting an ejection tray of the sheet finishing apparatus of FIG. 1;  
         [0024]    [0024]FIG. 10 is a perspective view of an elevation mechanism for elevating the ejection tray; and  
         [0025]    [0025]FIG. 11 is a flowchart of an exemplary procedure of an initial remaining sheet checking process performed by the sheet finishing apparatus of FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]    In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the present invention is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents which operate in a similar manner.  
         [0027]    Throughout the various figures like reference numerals are used to designate identical or corresponding parts.  
         [0028]    [0028]FIG. 1 depicts a sheet finishing apparatus  1  according to a preferred embodiment of the present invention. As shown in FIG. 1, the sheet finishing apparatus  1  includes a sheet inlet  101  that is connected to an image forming apparatus  2 . A sheet passage following the sheet inlet  101  is provided with an inlet sensor  136 , a pair or inlet rollers  115 , and a branch pawl  108 . The branch pawl  108  switches the directions of advancing sheets either to an ejection tray  112  or to a stapling apparatus  111 . A sheet passage connected to the ejection tray  112  is provided with upper passage rollers  102 , an ejection sensor  138 , an ejection roller  103 , a shift roller  107 , a sheet level lever  113 , and a sheet level sensor  133 . A sheet passage connected to the stapling apparatus  111  is provide with lower passage rollers  104 , an ejection sensor  137 , and sheet feed rollers  106  (i.e., brush rollers). The lower passage rollers  104  are driven by a motor, i.e., a feed motor  54  (described below and depicted in FIG. 8), and the ejection tray  112  is moved in horizontal and vertical directions by motors, for example, a vertical motor  51  and a shift motor  52  (both described below).  
         [0029]    The stapling unit  111  is mounted under a stapling tray  121 . The stapling tray  121  is provided with jogger fences  109  for jogging a stack of sheets stacked on the stapling tray  121 , a return roller  105 , and a lifting belt  110  for lifting a stack of stapled sheets. The lifting belt  110  is arranged behind the jogger fences  109  and includes a lifting pawl  110   a.  In FIG. 1, reference numeral  119  denotes a trailing edge fence and reference numeral  139  denotes a sheet detecting sensor.  
         [0030]    [0030]FIG. 2 depicts a jogging mechanism of the sheet finishing apparatus  1 . As shown in FIG. 2, the jogger fences  109  are configured to travel leftward and rightward due to the clockwise and counterclockwise rotation of a jogger belt  149  driven by a jogger motor  126 , which is rotated in forward and backward directions. The return roller  105  is moved back and forth by a return solenoid  130  so as to move away from the surface of the sheet in a transferring process. Reference numeral  147  denotes a driving belt which transmits a driving force generated by the feed motor  54  to one of the sheet feed rollers  106  and to one of the lower passage rollers  104  (FIG. 1).  
         [0031]    The trailing edge fence  119  is arranged under the jogger fences  109  to receive the trailing edge of the sheet after the completion of the transferring process. In this case, the sheet is sent downwards by the return roller  105 , driven by the return solenoid  130 , and the sheet feed rollers  106  along the jogger fences  109 . Thereby, the sheets are jogged at the trailing edge sides by the trailing edge fence  119 , as shown in FIG. 3.  
         [0032]    As shown in FIG. 4, the trailing edge fence  119  includes a left fence  119   a,  a right fence  119   b,  and a center fence  119   c  that are arranged at left, right, and center sides, respectively, and are movably engaged with the stapling unit  111  in a manner independent of one another.  
         [0033]    The ejection sensor  137  is arranged at a position such that the return roller  105  contacts the trailing edge surface of the sheet when the ejection sensor  137  detects the trailing edge of the sheet and the return solenoid  130  activates the return roller  105 .  
         [0034]    The stapling unit  111  is moved in the left and right directions, as shown in FIG. 4, by the rotary movement of a stapling belt  150  driven by a stapler shift motor  127 , which is rotated in the forward and backward directions. The stapling unit  111  performs a stapling operation in a variety of ways such as a single front stapling, a single deep-inside stapling, a double stapling, etc. In FIG. 4, reference numeral  122  is a home position sensor for detecting a home position of the stapling unit  111 .  
         [0035]    [0035]FIG. 5 shows positions of the jogger fences when the sheets are jogged in the stapling tray  121  and FIG. 6 shows positions of the jogger fences when the jogger fences are moved at the most external position to allow the user to pick up the sheets. As shown in FIGS. 5 and 6, the stapling tray  121  is mounted on the sheet finishing apparatus  1  and the jogger fences  109  are moved back and forth along shafts  151  and  152 . The jogger fences  109  can be located at three different positions: a widest expanding position for the jogger fences  109  shown in FIG. 5; a sheet jogging position shown in FIG. 6; and a home position. The home position is arranged close to the widest expanding position. The widest expanding position is arranged to maintain at least a distance L between the jogger fence  109  and a front-and-side plate  153  which is a part of a housing of the apparatus so that the sheets is easily taken out from an opening  154 .  
         [0036]    Each jogger fence  109  includes a first regulating portion  109   a  for jogging the sheet in a direction perpendicular to the sheet transferring direction and a second regulating portion  109   b  for regulating the sheets stacked in the stapling unit  121  in the direction of thickness of the sheet. The above-mentioned distance L is defined as a distance between an edge portion  109   c  inside the second regulating portion  109   b  and an edge portion  154   a  of the opening  154 , which faces most closely the edge portion  109   c.    
         [0037]    The lifting belt  110  is moved by a reverse-rotatable lifting belt motor  157  in the sheet transferring direction, as shown in FIG. 7. That is, the lifting belt  110  is moved upwards when the stack of sheets is lifted up for ejection and downwards when the stack of sheets is in a process of jogging in the sheet transferring direction. In addition to the jogging operation with the return roller  105  and the trailing edge fence  119 , the leading edge jogging is also performed when the sheets are in one size. That is, a lower edge portion  110   b,  which is a rear side of the lifting pawl  110   a,  is brought into contact with the leading edge of the stack of sheets. When a multiple sheet transfer is performed, the return roller  105  is moved to contact the first sheet and therefore the above-mentioned jogging by the lower edge portion  110   b  is needed.  
         [0038]    Next, an exemplary configuration of a microcomputer circuit  3  provided in the sheet finishing apparatus  1  is explained with reference to FIG. 8. As shown in FIG. 8, the microcomputer circuit  3  includes a central processing unit (CPU)  70  to which signals from various switches of a control panel (not shown) and the sensors are input via an input and output (I/O) interface  60 . In response to the input signals, the CPU  70  activates the vertical motor  51 , the shift motor  52 , a branch solenoid  53 , the sheet feed motor  54 , an ejection motor  55 , the jogger motor  126 , the stapler shift motor  127 , the return solenoid  130 , a stapling motor  156 , the reverse-rotatable lifting belt motor  157 , and a punch motor (not shown). Pulse signals generated by the sheet feed motor  54  are input to and counted by the CPU  70 . In response to a value of this count, the return solenoid  130  is controlled. A synchronous control means includes the CPU  70  and a variety of operation programs including a program explained later and shown in FIG. 11.  
         [0039]    An operation of the sheet finishing apparatus  1  in a non-stapling mode is explained below. A sheet sent from the image forming apparatus  2  and which has therefore been subjected to the image forming process is received by the sheet inlet  101  and is sent to the upper passage by the branch pawl  108 . The sheet is then fed by the sheet passage rollers  102  and is ejected by the ejection roller  103 . The sheet is jogged by the shift roller  107  in the sheet transferring direction and is stacked in the ejection tray  112 . The rotation speed of the shift roller  107  is reduced when the ejection sensor  137  detects the trailing edge of the sheet so as to make sure that the sheet is ejected into the ejection tray  112 . As a plurality of the sheets are stacked in the ejection tray  112 , the sheet level lever  113  and the sheet level sensor  133  detect the height of the sheet surface and, in accordance with this height, the vertical motor  51  is driven so that the height of the sheet surface is kept at a predetermined level.  
         [0040]    During a sorting mode and a stacking mode, the microcomputer circuit  3  receives a sheet separation signal from a control circuit of the image forming apparatus  2  and, in accordance with the sheet separation signal, instructs the shift motor  52  to move the ejection tray  112  so that the ejection tray  112  shifts in the direction transverse relative to the sheet transferring direction from time to time until the job is ended. The shift operation is performed such that an end fence  123  is slid with a cylindrical cam  124  and a cam follower  123   a  driven by the shift motor  52 , as shown in FIG. 9. A stop position of the ejection tray  112  is detected by a shift sensor  135 . The ejection tray  112  is moved down for approximately thirty millimeters when the job is ended.  
         [0041]    An operation of the sheet finishing apparatus  1  in a stapling mode is explained below. When the stapling mode is selected, the jogger fences  109  are moved from their home positions to standby positions approximately seven millimeters away from the edges of the sheet, as shown in FIG. 2. The sheet is transferred by the lower passage rollers  104  which are driven by the sheet feed motor  54 . When the trailing edge of the sheet passes the position of the ejection sensor  137 , the jogger fences  109  perform the jogging process towards the inside directions relative to positions five millimeters away from the standby positions. The ejection sensor  137  detects the trailing edge of the passing sheet and sends a signal to the CPU  70  which will then start to count the pulses generated by the sheet feed motor  54  and drives the return solenoid  130  when the count number reaches a predetermined value. The return roller  105  is moved back and forth by the on-and-off motion of the return solenoid  130 . When the return solenoid  130  is turned on, the return roller  105  touches the sheet to move it down. The sheet is thus dropped and stopped by the trailing edge fence  119 . As a result, the sheets are jogged. During the above operation, when the inlet sensor  136  detects the sheet, it sends a signal to the CPU  70  which will count the number of this signal and regards it as information indicating a number of sheets stacked in the ejection tray  121 .  
         [0042]    In a predetermined time period after the return solenoid  130  is turned off, the jogger fences  109  are moved 2.6 mm inside by the jogger motor  126  and are stopped there, thereby completing the jogging in the directions transverse relative to the sheet transferring direction. The jogger fences  109  are then moved backwards again for 7.6 mm and are stopped to wait for the next sheet.  
         [0043]    The above-described operations are repeated in each sheet handling cycle until the last sheet of the job is finished. During the operation for the last sheet of the job, the jogger fences  109  are caused to perform the 7.6 mm jogging operation again at the end of the process so as to hold both sides of the stack of sheets in preparation for the stapling process. At a predetermined time after this repeated jogging process, the stapling unit  111  begins to perform the stapling process. When the stapling unit  111  is in the double stapling mode, after the first stapling process is ended, the stapling unit  111  is moved by the stapler shift motor  127  to the second stapling position along the trailing edge of the sheet so as to perform the second stapling process.  
         [0044]    After the stapling operation, the lifting belt motor  157  is driven to move the lifting belt  110 . At the same time, the ejection motor  55  is also driven so that the stack of sheets lifted up by lifting pawl  110   a  is received. The jogger fences  109  are controlled to differently perform the jogging operation depending upon the size of the sheet and the number of sheets to be stacked. For example, when the size of the sheet is smaller than a predetermined size or when the number of sheets to be stacked is smaller than a predetermined number, the stack of sheets is held at both sides thereof by the jogger fences  109  and is lifted up at the trailing edge thereof by the lifting pawl  110   a.  In a certain time period corresponding to a predetermined number of pulses counted by a home sensor (not shown) for the lifting belt  110 , the jogger fences  109  are moved outwards 2.6 mm away from the present positions to release the stack of sheets. This predetermined number of pulse counts is defined as a number to correspond a time period from a time the trailing edge of the sheet touches the lifting pawl  110   a  to a time the lifting pawl  110   a  is moved above the jogger fences  109 . When the size of the sheet is greater than a predetermined size or when the number of sheets to be stacked is greater than a predetermined number, the jogger fences  109  is initially moved outwards 2.6 mm away from the present positions and the stack of sheets is then lifted up at the trailing edge thereof by the lifting pawl  110   a.  In any case when the stack of sheets is moved above the jogger fences  109 , the jogger fences  109  are moved further outwards back to the standby positions for the next sheet. The force of the jogger fences  109  used to hold the stack of sheets can be changed by adjusting the distance of the jogger fences  109  relative to the stack of sheets. The above series of the processes are repeated to the last sheet.  
         [0045]    As shown in FIG. 10, the ejection tray  112  is hung with lifting belts  148 . The lifting belts  148  are driven by the vertical motor  51 , each via a series of gears and a timing belt. The lifting belts  148  are moved upwards and downwards according to the forward and reverse rotations of the vertical motor  51 . The home position and the travel position of the ejection tray  112  is detected by the sheet level sensor  133  with the sheet level lever  113 . A lower limit sensor (not shown) is used to detect when the ejection tray  112  is filled with the stack of sheets. Further, when the ejection tray  112  touches the shift roller  107  during the elevation, it is detected by an upper limit sensor (not shown) and the vertical motor  51  is stopped so as not to overrun.  
         [0046]    [0046]FIG. 11 shows an exemplary procedure of an initial remaining sheet checking process for checking if any sheet remains in the stapling tray  121  at a power-on time. This process is performed by the above-described sheet finishing apparatus  1 . In the process diagramed in FIG. 11, the stapling tray  121  is checked when the power is switched on and, if it detects an event that a sheet is present in the stapling tray  121 , the jogger fences  109  are moved outwards so that the sheet can be taken out manually by the user. The detection of the sheet inside the stapling tray  121  is performed by the sheet detecting sensor  139 .  
         [0047]    In Step S 1  of FIG. 11, the CPU  70  checks whether a power-on flag is high, wherein when the power is on the power-on flag is high and when the power is off the power-on flag is low. When the power-on flag is low, the process ends. When the power-on flag is high, the power-on flag is reset to low, in Step S 2 . The power-on flag is normally preset to high before the program enters a main routine after the CPU  70  is initialized when the main power is switched on.  
         [0048]    Then, in Step S 3 , the CPU  70  checks the status of the sheet detecting sensor  139 . If the sheet detecting sensor  139  is off and the check result of Step S 3  is NO, the process ends. If the sheet detecting sensor  139  is on and the check result of Step S 3  is YES, a jogging sub-routine for performing the jogging process is initiated, in Step S 4 . By performing the jogging sub-routine, the jogger fences  109  of the stapling tray  121  are moved outwards. As described above, the jogger fences  109  are driven by the jogger motor  126  so as to move away from each other. In this process, it is preferable that the jogger fences  109  are expanded for a sufficient distance for the user to be able to pick up the sheet present in the stapling tray  121 , for example. It is also preferable that the jogger fences  109  are moved outwards until it comes close to the home position sensor  122  for the stapling unit  111 . The home position sensor  122  for the stapling unit  111  is mounted at or close to the home position of the jogger fences  109  where the jogger fences  109  are expanded outwards for the maximum extent, as describe above.  
         [0049]    With the above arrangement, the user is provided with sufficient space to remove a jammed sheet, for example, without the need for unifying the stapling tray  121  and the stapling unit  111  into one unit in order to be drawn out to remove the jammed sheet. The present embodiment provides for the movement of the jogger fences  109  towards the operation side (the left side in FIG. 5) for a distance sufficient to extend through the opening  154  such that the operator can remove the paper jam without having to pull the stapling tray  121  and stapling unit  111  out of the sheet finishing apparatus. Such a configuration is not present in the related art structures, which require the stapling tray and stapling unit be provided in one unit in order to facilitate removal of a paper jam.  
         [0050]    When the stapling mode is cancelled during the execution of the stapling mode, or when a power-down is caused before a paper jam error is cleared, the sheet erroneously remains in the apparatus and the jammed sheet is needed to be removed from the apparatus when the power is next turned on. In such a case, if the jogger fences  109  are located at the most outward positions as described above, the user can easily recognize that a sheet remains in the apparatus by checking the position of the jogger fences  109  and can easily remove the remaining sheet through the reserved opening  154 .  
         [0051]    Obviously, numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.  
         [0052]    This document is based on Japanese Patent Application No. JPAP2000-188059 filed on Jun. 22, 2000, in the Japanese Patent Office, the entire contents of which are incorporated herein by reference.