Patent Document

[0001]     This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 04075873.2 filed in Europe on Mar. 18, 2004, which is herein incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a method for the post-processing of sheets processed by a sheet processing apparatus provided with a sheet punching device for punching a set of two or more spaced holes in sheets, wherein the method includes the step of punching the set of holes in all sheets of a first batch, in a first, standard, position, wherein the sheets of the first batch have substantially equal size and orientation.  
         [0003]     The present invention also relates to a sheet processing apparatus provided with a sheet punching device for punching holes in a sheet member such as a sheet of paper (hereafter referred to as a sheet).  
         [0004]     Sheet punching devices are typically installed in a sheet processing apparatus such as a printer, a photocopying machine, a facsimile or a sheet post processing apparatus connected with an image processing apparatus. The sheet processing apparatus may perform several post-processing operations including, for example, a stack operation for stacking sheets on an output tray, a staple operation for stapling sets of sheets, and a punching operation for punching a sheet or sheets with the sheet punch device.  
         [0005]     Background sheet punch devices are divided into two types depending on the driving method for driving a punch to create a hole in a sheet, i.e., (1) a press punch method and (2) a rotary punch method. Both types of punch devices can be used in connection with the present invention.  
         [0006]     U.S. Pat. No. 6,120,015 discloses a press punch-type sheet punching device for punching holes in sheets outputted by a printing system, with a common sheet entrance path, two separate but closely vertically superposed sheet paths, a gating system alternately gating the unpunched sheets into one of said two separate sheet paths having respective separate (but shared) components, sheet punching stations with common reciprocally, vertically driven sheet punches. The sheets are alternately stopped and the desired hole patterns are alternately punched, and the sheets ejected, in the two separate sheet paths, individually punched, or punched simultaneously as stacked sets.  
         [0007]     U.S. Pat. No. 6,305,262 discloses a sheet punch device including one or more punching units having a rotatable punch that punches a hole in a sheet, a driving member that drives and rotates the punch member to punch a hole in a conveyed sheet, and in which the punch member punches holes in the conveyed sheet at plural places aligned in a sheet conveying direction. Also included is a control device that controls the driving member such that the punch member punches a predetermined number of holes in the conveyed sheet sequentially at predetermined positions aligned in the sheet conveying direction. The punch units may be displaced to adapt to different paper sizes and/or and hole configurations selected by an operator. The sheet punch device is part of a post processing apparatus of an image forming device. Via a graphical user interface an operator can select the number of holes per sheet from a number of standard configurations (i.e. two, three, four or five holes per sheet). The user interface also allows the operator to choose for the holes to be aligned along the height or along the width of the sheet. These choices are limited to a number of standardized positions.  
         [0008]     Generally, punching holes in documents for filing purposes is governed by a number of national and international standards such as International standard ISO 838, US military standard MIL-STD-1160 (FSC 7530) and German industry standard DIN 821. Other national standards exist and are in use.  
         [0009]     U.S. Pat. No. 6,065,383 also discloses a punching mechanism displaceable to any of a plurality of punching positions in order to correctly punch holes in the standardized positions in different paper sizes.  
       SUMMARY OF THE INVENTION  
       [0010]     Sheets are punched in order to place them subsequently in a ring binder or the like. The document or documents in a ring binder are often organized by dividing or subdividing them into chapters or the like that are separated by inserting tabulation (TAB) or other separating sheets into the stack. These separating sheets are either inserted manually or automatically if the paper processing device is capable of inserting tab sheets automatically. However, inserting separating sheets into a printed set is at the cost of additional sheets and either additional labour or a more complex device control.  
         [0011]     The present invention has determined that by a relatively small adaptation of the punching functionality, sheets can be made to stand out in a stack, thereby obviating any other separating elements.  
         [0012]     On this background, it is an object of the present invention to provide a method of post-processing, i.e., punching, sheets processed by a sheet processing apparatus provided with a sheet punching device with an extended functionality.  
         [0013]     This object is achieved by allowing an operator of the sheet processing apparatus to specify at least one second batch of sheets having substantially the same size and orientation as the sheets of the first batch, and shift the position in which a set of holes is to be punched in the sheets of the second batch to a second position, and punching the set of two or more spaced holes in the second position in the sheets of the second batch, thereby creating a staggered stack of sheets by stacking subsequent first and second batches of sheets with holes aligned, such as by placing them in a ring binder.  
         [0014]     Accordingly, the thus processed sheets form a staggered stack or a stack with emulated TAB sheets. Different parts of a stack of sheets, the abovementioned batches, such as different documents or different chapters can be separated in this way without the need for inserting TAB sheets, because the different parts have an offset with respect to one another. This makes it far more comfortable for a reader to go through the documents because the borders between the different parts are explicit, which is especially helpful when the different parts are not stapled. The thus processed sheets form an aligned stack with emulated tab sheets if the shift is applied to a single sheet at a time, e.g. the starting page of each document or chapter. The emulated tab sheets can also be formed by additional sheets that are inserted before the start of a new document or chapter. The emulated TAB sheets may be printed with TAB information on the part of the sheet that does not overlap with the stack.  
         [0015]     In a preferred form, the first position mentioned above is the conventional standard position, such as required by the already mentioned industry standards ISO, DIN, etc., and the second, different punching position is a non-standard position.  
         [0016]     The shift can be in the direction of the width or of the height of the (usually) rectangular sheets, or both, and preferably extends over a relatively small distance, such as a few millimeters, but generally not more than 2 cm.  
         [0017]     According to a second aspect of the present invention there is provided a sheet processing apparatus comprising a sheet punching device for punching a set of two or more spaced holes arranged on an imaginary line in sheets processed by the apparatus, and further comprising a processor unit for controlling the apparatus, including the punching device, wherein the processor unit controls the apparatus in punching the set of holes in all sheets of a first batch, in a first, standard, position, the sheets of the first batch having substantially equal size and orientation. The processing apparatus also enables an operator to specify at least one second batch of sheets having substantially the same size and orientation as the sheets of the first batch, and also to specify a shift of the position in which said set of holes is to be punched in the sheets of the second batch, to a second position, and to control the apparatus in punching the set of two or more spaced holes in the second position in the sheets of the second batch, thereby creating a staggered stack of sheets, by stacking subsequent first and second batches of sheets with holes aligned, such as by placing them in a ring binder.  
         [0018]     Accordingly, the sheet processing apparatus is capable of processing a set of sheets that is staggered or provided with TAB emulated sheets when it is afterwards placed in a ring binder—with the advantages as described above.  
         [0019]     Further objects, features, advantages and properties of the methods, apparatus and system according to the present invention will become apparent from the detailed description.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiments shown in the drawings, wherein:  
         [0021]      FIG. 1  illustrates a preferred embodiment of the a sheet processing device,  
         [0022]      FIG. 2  illustrates another preferred embodiment of the a sheet processing device,  
         [0023]      FIG. 3  illustrates the control structure of the sheet processing device,  
         [0024]      FIG. 4 . is a side view of a punching device,  
         [0025]      FIG. 4   a  is a enlarged section of  FIG. 4 ,  
         [0026]      FIG. 5  is a top view of the punching device of  FIG. 4 ,  
         [0027]      FIG. 6  shows a detail of the punching device of  FIG. 4 ,  
         [0028]      FIG. 7  illustrates a staggered stack with aligned punching holes,  
         [0029]      FIG. 8  illustrates the staggered stack of  FIG. 7  placed in a ring binder,  
         [0030]      FIG. 9  illustrates a stack provided with emulated TAB sheets and aligned punching holes,  
         [0031]      FIG. 10  illustrates the stack of  FIG. 9  placed in a ring binder,  
         [0032]      FIG. 11  illustrates a user interface of a control unit on a sheet processing device, and  
         [0033]      FIG. 12  illustrates a user interface of a control unit on a workstation. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]     In the following detailed description, a sheet processing apparatus according to the present invention in the form of a digital printer, scanner and copier will be described by the preferred embodiments.  
         [0035]     The printing apparatus  1  shown in  FIG. 1  comprises means known per se for printing an image on a receiving sheet. These images for printing may be present on original documents which are fed to a scanning station  2  situated on top of the printing apparatus  1 . Images for printing can also be fed in digital form from a workstation  3  connected via a network  4  to a control device  8  of the printing apparatus  1 . A printing cycle for copying an original set fed via the scanning station  2  is started by actuating a start button  6  on the operator control panel  5  of the printing apparatus  1 .  
         [0036]     A printing cycle for printing an image set fed via workstation  3  can be started by actuating a start button  7  provided on the workstation  3 , via control device  8  or by actuating a start button  6  provided on the operator control panel  5  of the printing apparatus  1 .  
         [0037]     The workstation  3  creates print orders and passes them on to printer  1 . A print order contains a digital document and, in addition to digital data which determine the content of the document, can also contain data which specify the appearance of the finally printed document, such as the image supports to be used, for example sheets of paper of a specific size and color, simplex or duplex printing, finishing by stapling, gluing, punching etc.  
         [0038]     Several workstations may be coupled, via a data network, to a print server (a suitably programmed PC), which receives print orders from the workstations, pre-processes them if necessary, and passes them on to one or more printers which are also coupled (not shown).  
         [0039]     In the printing apparatus  1  shown in  FIG. 1 , the sheet transport path  10  forms the path for delivering to a sheet finishing station  11 , the sheets printed in the printing apparatus.  
         [0040]     The finishing station  11  contains a sheet punching device  20  that will be described in more detail later and a sheet collecting tray  12  (not shown in detail) in which a number of printed sheets belonging to a set can be collected and stapled, whereafter discharge roller pairs  13  feed the set to a sheet depositing device  18  forming part of a sheet depositing station.  
         [0041]     The sheet depositing device  18  shown in  FIG. 1  comprises two superposed depositing platforms  16  and  17 , upon which sheets are sequentially stacked. The sheet depositing device  18  is capable of creating staggered stacks.  
         [0042]      FIG. 2 . illustrates another embodiment of the present invention by a stand alone (i.e., not connected to a network) copying machine  1  provided with an operator control unit  15  including a graphical user interface, in which a choice can be made from a number of hole punching positions. These positions include punching holes along the height or along the width of the sheet. The number of holes to be punched and their size can be selected on the operator control unit  15 . The latter may also be equipped with a page programming function by means of which it is possible to make settings for each copy image. The copying machine may be digital, i.e., a combination of a scanner and a printer, but it may also be an analogue machine, i.e., a machine which images an original document directly and prints it on copying sheets.  
         [0043]      FIG. 3  illustrates the control structure of the sheet processing device. The control unit  19 . 1  controls the operation of the printer  1  and interfaces with the user interface  19 . 2 , the scanner  19 . 3 , the input handler  19 . 4 , the print engine  19 . 5 , the sheet punching device  20  and the output unit  11 . The input handler  19 . 4  is connected to the network  4 . Print jobs are received via the network by the input handler. The input handler  19 . 4  sends the job settings, including, e.g., punch settings to the control unit  19 . 1 . The input handler  19 . 4  sends the digital job to the print engine  19 . 5  that prints the images on sheets. The printed sheets are then conveyed to the punching unit  20  that creates holes in the printed sheets in accordance with settings received from the control unit. The sheets are then conveyed to the output unit  11  and are treated (e.g., stapled and/or stacked) by the output unit in accordance with the settings received from the control unit  19 . 1 .  
         [0044]      FIGS. 4, 4   a  and  5  illustrate the sheet punching device  20  in detail. The sheet punching device  20  is placed in the sheet transport path  10 . The sheets enter the punching device one by one via entry rollers  21 . The sheets pass three sequentially spaced punching units  35 , 36  and  37 , and leave the punching device one by one via exit rollers  28 .  
         [0045]     The entrance rollers  21  and exit rollers  28  each include a pair of rollers, and are rotatively supported by respective shafts  22  and  29 . The shafts  22 , 29  extend between a pair of side boards (not shown) provided on each side of the sheet conveying path  10  of the sheet post-processing apparatus  11 , and oppose each other in the direction perpendicular to the sheet conveying direction indicated by an arrow X (hereinafter referred to as a sheet width direction X). The entrance rollers  21  receive a sheet and transfer the sheet in the downstream direction of the sheet conveying path  10 . The exit rollers  29  are provided immediately downstream of the rotary punching units  35 ,  36  and  37 , and transfer the sheet conveyed in the downstream direction of the sheet conveying path  10  towards the sheet collecting tray  12  ( FIG. 1 ).  
         [0046]     The entrance rollers  21  and the exit rollers  29  are in a relationship wherein a rotational force is transmitted to each other via a rotational force transmission device, such as a timing belt (not shown) and a belt pulley (not shown). The entrance rollers  21  and the exit rollers  29  are driven to rotate by a sheet conveying/driving device, such as a stepping motor (not shown).  
         [0047]     An entry sensor  32  connected to the control unit is disposed just downstream of the entry rollers  21  to detect leading and trailing edges of the sheet conveyed from the discharging rollers  21 , and thus serves as a sheet edge detecting device.  
         [0048]     Each punching unit  35 , 36 , 37  includes pairs of cooperating rollers  26 , 30  between which the sheets pass. The rollers  26 , 30  of a pair are spaced sufficiently apart for the sheets to pass in between without the rollers getting a grip on the sheets. The upper roller  26  is provided with a punch  27  and the lower roller  30  forms a die member with recess  27   a . As shown in more detail in  FIG. 4   a , the recess  27   a  is placed in the rim  30   a  of the roller  30 , and allows punching dust (not shown), that is produced when a sheet is punched, to leave the die.  
         [0049]     The upper roller  26  is placed on a drive shaft  24 , driven by an electric punch motor, such as a stepper motor (not shown) connected to the control unit. The lower roller  30  is placed on a drive shaft  31  that is connected to drive shaft  24  by a set of equally sized gearwheels (not shown). Rotations of the punch motor cause the upper roller  26  and the lower roller  30  to rotate in opposite directions respectively synchronizing with each other. The rotational position and speed of the rollers  26 ,  30  can be accurately controlled with the punch motor.  
         [0050]     Punching unit  35  is provided with two pairs of rollers  26 , 30  and is configured for punching two holes simultaneously. Punching unit  36  is provided with three pairs of rollers  26 , 30  and is configured for punching three holes simultaneously and punching unit  37  is provided with four pairs of rollers  26 , 30  and is configured for punching four holes simultaneously.  
         [0051]     The punching units can be provided with any other desirable number of sets of rollers in order to produce other numbers of holes simultaneously.  
         [0052]     The sheet punching device can also be provided with a punching unit with a single pair of rollers (not shown), preferably the first punching unit after the entry rollers, that is, capable of punching several holes on an imaginary line aligned with the sheet conveying direction X in a sequential manner by two or more rotations of the punching unit concerned.  
         [0053]     A container  33  below the punching units  35 , 36  and  37  receives the punch dust.  
         [0054]     A moving mechanism using e.g. an electromagnet (not shown) associated with each of the punching units  35 , 36  and  36  moves the punching unit concerned in the sheet height direction Y, i.e., perpendicular to the sheet conveying direction X. The moving mechanism is connected to the control unit and the axial position of the punching units can be changed with a signal form the control unit to the moving mechanism of the punching unit concerned.  
         [0055]      FIG. 6  shows in detail how the punching unit  35  can be shifted from a first punching position, illustrated by the dashed line style, to a second punching position illustrated by the solid line style, in the direction of the arrow Y by the moving mechanism. A sheet  30  punched with the punching unit  35  in the first position is illustrated in the dashed line style. This position corresponds to a conventional standard punching position, such as defined in ISO 383 or other industry standards. A sheet  30  punched with the punching unit  35  in the second position is illustrated in the solid line style. The two holes are punched on an imaginary line  49 . A set of crosses indicates the first (standard) punching position, in which each hole is placed at an equal distance from the sheet symmetry line along arrow X. The second punching position is displaced downwards with respect to the standard punching position, such that the sheet will stick out of the stack upwardly, when placed in a ring binder. Of course, other shifts may be chosen.  
         [0056]     The sheets enter the punching device one by one through exit rollers  21  and sheets do not stop during the punching operation but move along the sheet conveying path at normal speed. When it is chosen to have two holes in the document, punching unit  35  with the two punches  27  is active. The other punching units  36  and  37  are not active, so their punch  27  is in an upper position as show in  FIG. 4 .  
         [0057]     The control unit synchronizes the activation of the punching unit  35 —on the basis of the signal from the entry sensor  32 —with the movement of the sheet along the sheet conveying path  10 , to place the holes correctly in the X-direction. The punching position can be shifted in the X-direction by changing the synchronization, i.e. by delaying the activation of the punching unit, the punching position moves to the left, and by advancing the activation of the punching unit the punching position moves to the right.  
         [0058]     If an offset in the Y-direction is needed the punching unit concerned is moved along its longitudinal axis by the moving mechanism with the offset distance needed. The offset can also be in both the X-and the Y-direction (not shown).  
         [0059]      FIG. 7  illustrates a stack  40  of sheets processed by the printing apparatus  1 . The sheet depositing device  18  has created a staggered stack so that different parts of the stack can be easily identified. The stack comprises parts  42  that are not shifted and parts  43  that are shifted to the left (as in  FIG. 7 ).  
         [0060]     The punching device  20  has punched the holes  45  in different positions for the different parts of the stack. Parts  42  have been punched at the central standard two hole-punching position. Parts  43  have been punched with a shift from the central standard two hole-punching position in the Y-direction to the right (right as in  FIG. 7 ). Also contemplated within the scope of the present invention is shifting each of the two punching positions over an equal distance in opposite directions from the standard position, which results in a more central placing of the overall stack in the binder.  
         [0061]     Obviously, the punching displacement does not necessarily have to be equal to the stacker offset, but if it is, it brings convenience to the user who wants to put the complete pack in a ring binder or the like.  
         [0062]     The offset between the parts  42  and  43  is equal to the distance between the two punching positions. The holes in the sheets are therefore aligned for the complete stack.  
         [0063]      FIG. 8  illustrates the stack  40  placed in a ring binder  50 . The offset between the parts  42  and  43  is maintained in the ring binder  50  and the parts  42  and  43  of the stack can be conveniently identified by a user without having to add TAB sheets.  
         [0064]      FIG. 9  illustrates a stack in which only single sheets have been punched in a different punching position, in order to allow them to emulate TAB sheets.  FIG. 10 . illustrates the stack of  FIG. 9  placed in a ring binder  50 .  
         [0065]      FIG. 11  illustrates the user interface of the control unit  5  ( FIG. 1 ) or  15  ( FIG. 2 ). The control unit comprises a display  60 , and a keypad. The keypad comprises a line of six keys  61  placed under the display and a star shaped set of keys including four triangular navigation keys  62  and a round selection key  63 .  
         [0066]     The controller unit displays a control menu and information about the status of the printing unit on the display. The control menu gives access to the settings of the printing apparatus via a number of sub-menus. The punching settings sub-menu is shown in  FIG. 11 . The punching settings sub-menu comprises six columns  64 , 65 , 66 , 67 , 68  and  69 , one above each key  61 . Each column relates to a different aspect of the punching settings and is vertically divided into five fields. By pressing the key  61  below a column the marked setting changes from field to field in an endless loop manner.  
         [0067]     Column  64  relates to the activation of the hole punching feature. The lowest field of the column contains an “on” setting, the field there above contains an “off” setting.  
         [0068]     Column  65  relates to the number of holes per sheet and the associated hole size. The lowest field of the column contains a “2-holes, 5 mm” setting, the field there above contains a “3-holes, 9 mm” setting and the field there above contains a “4-holes, 5 mm” setting.  
         [0069]     Column  66  relates to the shift in punching position. The lowest field of the column contains a “none” setting, in which the holes are punched in the central standard position. The field thereabove contains a “TAB right” setting in which selected sheets in a print job are punched with a punching position that is shifted in the X-direction relative to the other sheets in the print job concerned. The distance of the shift between the standard position and the shifted position may be a pre-programmed manufacturer setting of the printer, or may be a device default, set by a key operator, and should be in the order of a few millimeters. In order to prevent the holes from tearing, the shift should not be more than about 6 mm. The field thereabove contains a “TAB up” setting in which selected sheets in a print job are punched with a punching position that is shifted in the Y-direction relative to the other sheets in the print job concerned. Generally, the shift distance would again be a pre-programmed setting. There can also be offered several shifted positions in one and the same direction, e.g. 6 mm up relative to the standard position and 12 mm up relative to the standard position.  
         [0070]     The highest field contains a “manual” setting. Upon activating this setting a pop up window (not shown) appears showing the X- and Y-shift distance. The X- and Y-shift distances can be adjusted by using the triangular navigation keys  62 . When the desired settings have been reached the setting can be activated by pressing the round selection key  63 .  
         [0071]     Column  67  relates to the selection of the sheets to be punched in the shifted position. The lowest field of the column contains an “all sheets” setting, in which all the holes are punched in a shifted position. This feature is, e.g., useful when a document needs to be added to a conventional stack of sheets within a ring binder, because the shifted punching position will let it easily be identified as the “added” document. The field thereabove contains a “enter numbers” setting for selecting the page numbers at which a shift in punching position has to take place. Upon activating this setting a window pops up prompting the user to enter the desired sheet numbers with a numerical keypad (not shown). After completing the numeric entry the setting is activated by pressing the round selection key  63 . The field there above contains a “bookmarks” setting. This setting informs the sheet punch device to shift punching position at every bookmark in the printing job. After activating this feature a pop up window displaying the page numbers of the bookmarked pages appears for providing feedback to an operator.  
         [0072]     Column  68  relates to the insertion of extra sheets when single TAB sheets are emulated. The lowest field of the column contains a “use document” setting, in which the TAB sheets are created from sheets of the document to be printed. The field thereabove contains an “insert blanks” setting in which the TAB sheets are created from sheets that are added to the document to be printed.  
         [0073]     Column  69  relates to the alignment of the printed images. The lowest field of the column contains a “paper” setting, in which the images are aligned with the paper, i.e. in the resulting staggered stack in a ring binder the printed images will, like the sheets, shift relative to the ring binder. The field thereabove contains a “document” setting in which the images are aligned with the document, i.e. in the resulting staggered stack in a ring binder the printed images of all pages will be aligned with the ring binder, and not shift like the sheets. This is achieved by shifting the position of printed image in the same direction and over the same distance as the shift in the punching position of the holes so that the images on all the sheets in the stack are aligned when the holes of all the sheets are aligned. A reader browsing the stack will thus not experience any jumps in image position.  
         [0074]     The same settings as described with reference to  FIG. 11  can be specified at the workstation  3 . Since the same settings are involved, the effect of the settings will not again be explained in detail.  FIG. 12  illustrates a user interface of a control unit on a workstation  3  in the form of a window  70  of the printer driver that pops-up after clicking with a mouse button on a “Punching” option in the printer driver. The pop-up window is divided in a “Simple hole punching” settings section  72  on the left and an “Advanced hole punching” setting section  73  on the right.  
         [0075]     The “Simple hole punching” settings section  72  contains an “On/Off” check box  74  for specifying if the hole punching feature is to be activated and a “Number of holes” selection box  75 .  
         [0076]     The “Advanced hole punching settings” section  73  contains a “Sheets” selection item  77  with a numeric entry box  78  and a “Bookmark” selection item  79  with a page display area showing the operator which pages in the print job are bookmarked. Finally, the selection item  99  (“All Sheets”) allows the operator to select a punch position shift for the entire document.  
         [0077]     The “Advanced hole punching settings” section  73  contains further a “Stagger offset” sub-section  80  and a “Sheets” subsection  87 . The “Stagger offset” sub-section  80  contains a “0” item  81  for selecting the standard position, a “TAB up” item  82 , a “TAB right” item  83 , and a “Manual” item  84  with a “Horizontal” selection box  85  and a “Vertical” selection box  86 . These items correspond in function to the items in column  66  of  FIG. 11 . The “Sheets” subsection  87 , which corresponds to column  68  of  FIG. 11 , contains an “Insert blanks” item  88  and a “Use document” item  89 , and an “Images” sub-sub-section  90 , which corresponds to column  69  of  FIG. 11  and contains an “Align to document” item  91  and a “Align to physical page” item  92 .  
         [0078]     When the operator has specified all the punching settings he/she can return to the printer driver by clicking on the “OK” button  93  and the punching settings are programmed into the print order. Alternatively, the operator clicks on the “Cancel” button  94  and any changes to the settings are not stored.  
         [0079]     The invention has been disclosed with reference to a single feed sheet processing device. The invention can however equally be applied to continuous feed sheet processing devices.  
         [0080]     The shape of holes does not need to be round, e.g., squared holes can be used. The number of holes per sheet is not limited to the numbers described in the above embodiments, e.g. 5, 17 and 23 holes per page can also be used. The holes do not need to be on one imaginary line, and the holes do not need to be placed near the edge of the sheet, e.g. a set of holes can be punched close to each side of a symmetry line of a sheet that is placed in a ring binder while folded over on the symmetry line concerned.  
         [0081]     The present invention can also be used in a punching device that also applies plastic reinforcing rings on the sheets around the holes, to prevent tearing of the punched holes.  
         [0082]     Although the invention has been disclosed with reference to a rotary punching device, a press punch device with a displaceable punching position could also be used. As in the rotary punching device, a punching position shift in the direction perpendicular to the sheet transport direction would be accomplished by a physical shift of the punching device in that direction, whereas a punching position shift in the direction of the sheet transport can easily be accomplished by a timing shift.  
         [0083]     While the preferred embodiments of the devices and methods have been described with reference to the environment in which they were developed, they are merely illustrative of the principles of the invention. Thus, other embodiments and configurations may be devised without departing from the spirit and scope of the appended claims.

Technology Category: 7