Patent Publication Number: US-7913990-B2

Title: Image forming system, image forming apparatus and program

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an image forming system, an image forming apparatus and a program, and more particularly, it relates to an image forming system having an image forming apparatus to form an image on a recording medium and a finisher to apply a finish processing to the recording medium, wherein the finisher is provided with a stacking tray on which the recording medium ejected from the image forming apparatus are stacked, the image forming apparatus, and a program to control the image forming system. 
     Heretofore, there has been a technology, as an image forming system, that alternately moves matching positions of recording mediums, and for example, a technology that alternately moves the matching positions by a predetermined amount in the ejection of the recording mediums to change the matching positions and stacks ejected recording mediums (see Patent Document 1). Also, a technology that precisely arranges the ejected recording mediums has been disclosed (see Patent Document 2). 
     [Patent Document 1]
         Tokkaihei 10-181981 (Japanese Non-Examined Patent Publication)       

     [Patent Document 2]
         Tokkai 2002-179326 (Japanese Non-Examined Patent Publication)       

     However, with the above background art, when a technology, that carries out an image formation of one group or plural groups of recording mediums relative to a document set and intermingles a recording medium to be finished and a recording medium to be non-finished in a single group, is applied, the matching positions of non-finished recording mediums and the finished recording mediums differ from each other, so that there arises a problem that the ejected recording mediums can not be taken out all together. 
     SUMMARY OF THE INVENTION 
     To overcome the abovementioned drawbacks in conventional image forming systems, it is an object of the present invention to provide an image forming system, an image forming apparatus and a program for controlling a image forming system, which make it possible for a user to operate them in an easy way, when a mixture mode, in which a non-finished recording medium and a finished recording medium are intermingled in a single group, is set. 
     Accordingly, the abovementioned object of the present invention can be attained by an image forming system, an image forming apparatus and a program for controlling an image forming system, described as follow. 
     (1) An image forming system, comprising an image forming apparatus to produce a printing material as one group of recording mediums or plural printing materials as plural groups of recording mediums from a single document set; and a finisher to apply a finish processing to said recording mediums ejected from said image forming apparatus, wherein said finisher is provided with a stacking tray on which said recording mediums, ejected from said image forming apparatus, are stacked, wherein said image forming system includes a controlling section to control so that, if a mixture mode, in which a non-finished recording medium and a finished recording medium are intermingled in a single group, is set, said non-finished recording medium and said finished recording medium within said single group are stacked at a same recording-medium stacking position on said stacking tray.
 
(2) An image forming apparatus for producing a printing material as one group of recording mediums or plural printing materials as plural groups of recording mediums from a single document set, comprising a controlling section to control a finisher which applies a finish processing to a recording mediums ejected from said image forming apparatus, said image forming apparatus is capable of being coupled to said finisher, so that, if a mixture mode, in which a non-finished recording medium and a finished recording medium are intermingled in a single group, is set, said non-finished recording medium and said finished recording medium within said single group are stacked at a same recording-medium stacking position on a stacking tray provided on said finisher.
 
(3) A program for executing controlling operations of an image forming system, which comprises an image forming apparatus to produce a printing material as one group of recording mediums or printing materials as plural groups of recording mediums from a single document set and a finisher to apply a finish processing to said recording mediums ejected from said image forming apparatus, said program comprising the functional step of controlling said image forming system so that, if a mixture mode, in which a non-finished recording medium and a finished recording medium are intermingled in a single group, is set, said non-finished recording medium and said finished recording medium within said single group are stacked at a same recording-medium stacking position on a stacking tray provided on said finisher.
 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which: 
         FIG. 1  is a cross-sectional view showing the general configuration of an image forming system according to an embodiment; 
         FIG. 2  is a view showing the basic setting screen of an operating section according to Embodiment 1; 
         FIG. 3  is a view showing a page setting screen of the operating section according to Embodiment 1; 
         FIG. 4(   a ) and  FIG. 4(   b ) are cross-sectional views showing the configuration of a matching shift section and an ejecting section; 
         FIG. 5(   a ),  FIG. 5(   b ) and  FIG. 5(   c ) are illustrative view of the operation of a matching shift plate in the matching shift section; 
         FIG. 6(   a ),  FIG. 6(   b ) and  FIG. 6(   c ) are views showing recording-medium stacking positions on a stacking tray in Embodiment 1; 
         FIG. 7  is a block diagram of the electrical structure of the image forming system according to Embodiment 1; 
         FIG. 8  is a flow of determining recording-medium stacking positions on the stacking tray according to Embodiment 1; 
         FIG. 9  is a view showing a basic setting screen of the operating section according to Embodiment 2; 
         FIG. 10  is a view showing a page setting screen of the operating section according to Embodiment 2; 
         FIG. 11  is a view showing a page detail setting screen of the operating section according to Embodiment 2; 
         FIG. 12(   a ) and  FIG. 12(   b ) are stacking examples on the staking tray in the case in which offset is always prohibited in a mixture mode setting in Embodiment 2; 
         FIG. 13(   a ),  FIG. 13(   b ),  FIG. 13(   c ) and  FIG. 13(   d ) are stacking example on the stacking tray in the case in which the offset setting is established in the mixture mode setting in Embodiment 2; 
         FIG. 14  is a flow of determining recording-medium stacking positions on the stacking tray according to Embodiment 2; and 
         FIG. 15  is a flow of determining the recording-medium stacking positions on the stacking tray according to Embodiment 2. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, an image forming system, an image forming apparatus and a program of “Embodiment 1” and “Embodiment 2” according to the present invention will be described with reference to the drawings. 
     Embodiment 1 
     The mechanical structure, electrical structure and operation according to the image forming system and the image forming apparatus, as well as the program to control the image forming system will be described. 
     (General Description) 
       FIG. 1  is a cross-sectional view showing the general configuration of the image forming system according to the embodiment. As shown in  FIG. 1 , the image forming system is composed of an image forming apparatus  100  and a finisher  700 . The image forming apparatus  100  is equipped with a controlling section  800   a  in the image forming apparatus side, an operating section  200 A and an operating section  200 B of an external device, a document feeder  600 , a document reading section  300 , a paper feeding section  400 , and an image forming section  500 . The finisher  700  is equipped with a controlling section  800   b  in the finisher side, a recording medium conveyance section  709 , a stapler  704 , a punch unit  711 , a matching shift section  705 , an ejecting section  720 , and a stacking tray  708  on which recording mediums are stacked. 
     When a user set a document set, inputs job contents from the operating section  200 B (or  200 A) and issues an instruction of starting the image forming system, the document D placed on the document feeder  600  is fed out and read as image data in the document reading section  300 . The image data is sent to an exposure section  350  within the image forming section  500  in which a light based on the image data is output, and the output light condenses and images on a photoreceptor drum  504 . The photoreceptor drum  504  is charged on which an electrostatic latent image is formed by irradiating the light, and then the electrostatic latent image is developed by a development unit to form a toner image. A recording medium S fed from the paper feeding section  400  is fed to the image forming section  500  in which the toner image of the photoreceptor drum  504  is transferred onto the recording medium S. The recording medium S with the toner image transferred thereon is separated from the photoreceptor drum  504  by separation electrodes, and the separated recording medium is conveyed by a conveyer  509  to a fixing device  510  and fixed therein. The fixed recording medium S is reversed upside down in a recording-medium reverse section and fed into the finisher  700  from the image forming apparatus  100  by ejecting rollers  511 . 
     Of the recording mediums S conveyed to the finisher  700 , a recording medium S not to be finished is conveyed to a process tray  706  passing through a conveyance route a between a recording medium entry of the finisher  700  and a switching gate  710 , and through a conveyance route b between the upper side of the switching gate  710  and the process tray  706  by the conveyance rollers  701 ,  702 . While a recording medium S to be finished is once conveyed to the conveyance route a and the conveyance route b by the conveyance rollers  701  and  702 , switch backed by the conveyance rollers  702  and conveyed to a conveyance route c between the lower side of the switching gate  710  and the stapler  704  which is an example of the finishing section, and then is sent to the stapler  704 . A predetermined number of recording mediums S to be finished are gathered and stapled. The finished recording mediums S are conveyed to the process tray  706  passing through the conveyance route c and the conveyance route b by the conveyance rollers  703 ,  702 . The recording mediums conveyed to the process tray  706  are matched at a predetermined matching position in the matching shift section  705 , and then stacked at a predetermined recording-medium stacking position within the stacking tray  708  by the ejecting section  720 . 
     In the image forming system of the present embodiment, when a mixture mode in which non-finished recording mediums and finished recording mediums are intermingled within a group is established, the non-finished recording mediums and the finished recording mediums within the group are stacked at the same recording-medium stacking position on the stacking tray  708 . These are the descriptions of the general configuration of the image forming system according to the embodiment. 
     Mechanical Structure of Embodiment 1 
     Next, the mechanical structure of the image forming system according to Embodiment 1 will be described. Of the mechanical structure, the operating sections, the matching shift section  705  of the finisher, the ejecting section  720  and the stacking tray  708  will be described in detail. 
     The operating section  200 A shown in  FIG. 1  is provided in the upper portion of a document reading section  300 , wherein job contents can be established based on the contents operated by an operator. It is also possible to provide an external device (a PC) and job contents can be established based on the job contents sent from the operating section  200 B of the external device (PC). The operating sections  200 A and  200 B are mechanically the same, so that the description will be made about the operating section  200 B below. 
       FIG. 2  is a view showing the basic setting screen of the operating section  200 B according to Embodiment 1, and  FIG. 3  is a view showing a page setting screen in the operating section  200 B according to Embodiment 1. 
     In  FIG. 2  and  FIG. 3 , the operating section  200 B is composed of a keyboard  201 , a mouse  202 , and a liquid crystal section  203 . In the basic setting screen  204  of  FIG. 2 , offset, finish processing contents, a number of copies (a number of sets) and other related contents can be established. In offset, the switching of the matching shift position of recording mediums can be enabled or disabled. Further, the setting of whether to apply a finishing processing for every page can be made in the page setting screen  205  of  FIG. 3 . Incidentally, an example of a set will be described as an example of a group in the embodiment. 
     Herein, in the case of establishing the mixture mode and when inputting a designation of a finish processing to be applied in the basic screen of  FIG. 2 . (designating Stapling in  FIG. 2 ), the operator inputs off of the finish processing designation for the pages not to be finished in the page setting screen of  FIG. 3 . In the example of  FIG. 3 , the operator inputs off of stapling for 1-2 pages. 
     Incidentally, the operator may input a setting of pages to be finished in the page setting screen of  FIG. 3  without inputting the designation of a finish processing to be applied in the basic screen of  FIG. 2  (without checking the checkboxes of stapling and punch of the  FIG. 2 ). In this case, the operator inputs “1 Staple” for stapling of 3-4 pages. 
     Herein, it is assumed that a group of pages not to be finished and a group of pages to be finished are sub-groups respectively. There are two sub-groups of 1-2 pages and 3-10 pages in the embodiment. 
     Next, the matching shift section  705  and the ejecting section  720  will be described. 
       FIG. 4(   a ) and  FIG. 4(   b ) is are cross-sectional views showing the configuration of the matching shift section  705  and the ejecting section  720 , wherein  FIG. 4(   a ) is a cross-sectional view showing the partial configuration of the matching shift section  705  and ejecting section  720  as seen from the left side of the finisher, and  FIG. 4(   b ) is a cross-sectional view showing the configuration of the ejecting section  720  taken along the line A-A shown in  FIG. 4(   a ). Further,  FIG. 5(   a ),  FIG. 5(   b ) and  FIG. 5(   c ) are illustrative views of the operation of the matching shift plate in the matching shift section  705 . 
     In  FIG. 4(   a ), the matching shift section  705  is composed of a first unit  705 Ua shown in the right side of the figure to move one matching shift plate  705   a , and a second unit  705 Ub shown in the left side of the figure to move the other matching shift plate  705   b . Both of these units  705 Ua,  705 Ub have substantially the same configuration, so that the first unit  705 Ua will be described below as representing the two units. 
     The matching shift plate  705   a  is fixed in a carriage  708   a  capable of moving straight forward and backward sliding on a guide bar  707   a . The carriage  708   a  is fixed in a portion of a timing belt  712   a  strung between a drive pulley  713   a  and a driven pulley  714   a . The drive pulley  713   a  is driven and rotated from a drive motor M 3  which is a drive source via a gear g 1  and a gear g 2 . Reference numeral PS 1   a  denotes a home position sensor. Similarly the second unit  705 Ub is driven straight forward and backward by a drive motor M 2  which is another drive source via a train of the gears and the timing belt  712   b . As described above, the matching shift plates  705   a  and  705   b , which are respectively equipped with the dedicated drive motors, can move independently. The drive motors M 1 , M 2 , when operated by a signal from outside, drive the matching shift plates  705   a  and  705   b  to match recording mediums to place them at a predetermined position. 
     Next, in  FIG. 4(   b ), the ejecting section  720  ejects the recording mediums S in the process tray  706  to the stacking tray  708  ( FIG. 1) . A drive motor M 3  drives and rotates a circular disc  721  via a train of gears composed of a gear g 3  and a gear g 4 . An edge of a crank  722  with the other edge thereof supported at an eccentric position of the circular disc  721  is pivotably supported at a portion of a swingable ejection arm  724   a  around a fulcrum shaft  723 . Further, an extrusion arm  724   b  is pivotably supported at an edge of the ejection arm  724   a . The ejection arm  724   a  and the extrusion arm  724   b  are provided with a spring  725  therebetween, so that a spring force acts on the extrusion arm  724   b  in the clockwise direction. The circular disc  721 , which is driven and rotated by the drive motor M 3 , causes the crank  722  to make an eccentric motion and further causes the ejecting arm  724   a  and the extrusion arm  724   b  to swing. This swing motion of the extrusion arm  724   b  pushes a rear end portion of the recording medium S to eject it toward the stacking tray  708  ( FIG. 1 ). Incidentally, when the recording medium moves to the process tray  706 , the extrusion arm  724   b  can tilt in the counterclockwise direction and stand by in the figure. 
     Next, the operation of the matching shift plates  705   a  and  705   b  in the matching shift section  705  will be described.  FIG. 5(   a ) is an illustrative view of the case in which the recording medium is not shifted,  FIG. 5(   b ) is an illustrative view of the case in which the recording medium is shifted to the back side of the image forming apparatus, and  FIG. 5(   c ) is an illustrative view of the case in which the recording medium is shifted to the front side of the image forming apparatus. 
     At first, in  FIG. 5(   a ), the matching shift plates  705   a ,  705   b  move to positions at distances equal to a center line R in the conveyance direction of the recording medium S and match the recording medium at the central position of the image forming apparatus. In  FIG. 5(   b ), when offset with the back side of the image forming apparatus is established, the matching shift plates  705   a ,  705   b  move and stop at positions at different distances from the center line R in the conveyance direction of the recoding medium S and then matches the recording medium by shifting it to the back side of the image forming apparatus. Further, in  FIG. 5(   c ), when offset with the front side of the image forming apparatus is established, the matching shift plates  705   a ,  705   b  move and stop at positions at different distances from the center line R in the conveyance direction of the recording medium S and then matches the recording medium by shifting it to the front side of the image forming apparatus. 
     Next, the description will be made about stacking of the recording mediums on the stacking tray  708 . 
       FIG. 6(   a ),  FIG. 6(   b ) and  FIG. 6(   c ) are views showing the stacking state of recording mediums on the stacking tray  708  in Embodiment 1, wherein  FIG. 6(   a ) shows a portion of the configuration of the above described matching shift section  705 , and  FIG. 6(   b ) shows the state of an example of the recording mediums stacked in the mixture mode. Incidentally, in the embodiment, the stacking state is established by default as shown in  FIG. 6(   b ) in the mixture mode. It is also possible for the recording mediums to be offset for every sub-group and stacked as shown in  FIG. 6(   c ) by the selection setting of the operator even in the mixture mode. 
     In  FIG. 6(   b ), the stacking tray  708  is stacked with recording mediums that are shifted by the matching shift section  705  and ejected from the ejecting section  720  (see  FIG. 4(   a ) and  FIG. 4(   b )), wherein non-finished recording mediums S 1 , S 2  and finished recording mediums S 3  to S 10  constitute a group G 1  which is stacked at a same recording-medium stacking position P 1  of the stacking tray  708 . Similarly, a group G 2  is stacked at a recording-medium stacking position P 2 . Incidentally, the recording medium S 1  is the first recording medium of a job and a recording medium S 11  is the first recording medium of the group G 2  which is the second group. It is assumed that in  FIG. 6(   a ) and  FIG. 6(   b ), G 1  and G 2  are the same job in which the image formation of two sets of G 1  and G 2  is carried out based on the image data. 
     If the offset designation for every sub-group is established by the operator, as shown in  FIG. 6(   c ), the non-finished recording mediums S 1 , S 2  constitute a small group (sub-group) G 1   a  within the first group which is stacked at the recording-medium stacking position P 1 , and the finished recording mediums S 3  to S 10  constitute a small group (sub-group) G 1   b  within the first group (within the set) which is stacked at the recording-medium stacking position P 2 . These small groups G 1   a , G 1   b  constitute the first group G 1 . The same is true in the second group G 2 . 
     Electrical Structure of Embodiment 1 
     Next, electrical structure blocks and a flow of the program involving the recognition of recording-medium stacking positions in the image forming system according to the present embodiment will be described in relation to the electrical structure of the image forming system. 
       FIG. 7  shows the electrical structure blocks of the image forming system according to Embodiment 1. The electrical structure blocks are composed of electrical structure blocks in the image forming apparatus side and in the finisher side. In the electrical structure of the image forming apparatus side, reference numeral  200 AE denotes an electrical structure block of the operating section ( 1 )  200 A, reference numeral  200 BE denotes an electrical structure block of the operating section ( 2 )  200 B, reference numeral  600 E denotes an electrical structure block of the document feeder  600 , reference numeral  300 E denotes an electrical structure block of the document reading section  300 , reference numeral  500 E denotes an electrical structure block of the image forming section  500 , and reference numeral  400 E denotes an electrical structure block of the paper feeding section  400 . A memory M 1  is a memory that memorizes an initial position of the recording-medium stacking position, offset information and other parameters, a memory M 2  is a memory that memorizes page information, paper (recording medium) information and other information. The controlling section  800   a  in the image forming apparatus side controls each of the electrical structure blocks. Further, the controlling section  800   a  has first to fourth recognition sections. 
     The first recognition section  801  recognizes whether the mode is the mixture mode or not based on a finish processing designation which is input in  204  of  FIG. 2  and on the information about the existence or non-existence of the page setting which is input in the page setting screen  205  shown in  FIG. 3  (see F 3  of  FIG. 8  described below). 
     For example, the case of establishing a finish processing for an image formation of a document set composed of 10 pages is exemplified. When the checkbox of “Stapling” is checked in  204  of  FIG. 2 , and in the page setting screen  205  of  FIG. 3 , stapling for the first page is set to OFF and stapling for the fourth to tenth pages is set to OFF, this is the setting in which stapling is applied to the whole group and stapling is OFF for the first page and the fourth to tenth pages that are portions of the group. In other words, the setting is established so that only the second to third pages are stapled while the first page and the fourth to tenth pages are not stapled, thereby the setting is recognized to be the mixture mode in which the first page, the second to third pages, and the fourth to tenth pages constitute small groups respectively. 
     Similarly, when the checkbox of “Stapling” is not checked in  204  of  FIG. 2  and stapling for the second to third pages is set to ON in the page setting screen  205  of  FIG. 3 , this is the setting in which stapling is not applied to the whole group in  204  of  FIG. 2  and stapling is applied only to the second to third pages which are a portion thereof. In other words, similarly to the above example, the setting is established so that only the second to third pages are stapled while the first page and the fourth to tenth pages are not stapled, thereby this case is recognized to be the mixture mode as well. 
     On the other hand, when the checkbox of “Stapling” is not checked in  204  of  FIG. 2  and stapling is set to OFF for the second to third pages in the page setting screen  205  of  FIG. 3 , since the finish processing contents for the second to third pages and for the other pages are identical, in other words, the finish processing contents established between the first to second pages and between the third to fourth pages do not vary from each other, no small group exists within the group, and thereby the case is recognized not to be the mixture mode. 
     The second recognition section  802  recognizes whether the recording medium is the first recording medium of the second or later group of the job in the mixture mode (see F 4  of  FIG. 8 ). The third recognition section recognizes whether the recording medium is the first recording medium of the job (see F 1  of  FIG. 8 ). Further, the fourth recognition section  804  recognizes whether the recording medium is the first recording medium of the second or later group (the second set) or the first recording medium of a separation (see S 3 , S 13  of  FIG. 8   c ) in the non-mixture mode (see F 5  of  FIG. 8 ). 
     Herein, the separation is a boundary of a chapter and the like made by the user other than the group unit. 
     Next, in the electrical structure of the finisher side, reference numeral  709 E denotes an electrical structure block of the recording-medium conveyance section  709 , reference numeral  704 E denotes an electrical structure block of the stapler  704 , reference numeral  705 E denotes an electrical structure block of the matching shift section  705 , reference numeral  720 E denotes an electrical structure block of the ejecting section  720 , and reference numeral  711 E denotes an electrical structure block of the punch unit  711 . A memory M 3  is a memory for the paper feeding information (including the recording-medium stacking position information). The controlling section  800   b  in the finisher side controls each of the blocks in the finisher side. 
     The control of recognizing the recording-medium stacking position of recording mediums to the stacking tray  708  in the image forming system ( FIG. 8 ) is executed by the controlling section  800   a  in the image forming apparatus side, wherein the controlling section  800   a  sends its execution result to the controlling section  800   b  in the finisher side, and the controlling section  800   b  controls the ejection of the recording medium by controlling the matching shift section  705 E and other sections based on the information. 
     Next, the flow of the program involving the recognition of the recording-medium stacking position in the image forming system of Embodiment 1 will be described.  FIG. 8  is a flow of recognizing the recording-medium stacking position on the stacking tray in the image forming system of Embodiment 1. In  FIG. 8 , it is first recognized whether the recording medium is the first recording medium of the job by the third recognition section  803 , and when it is the first recording medium of the job, the process proceeds to the next step F 2 , while it is not the first recording medium of the job, the process proceeds to F 3  (F 1 ). When the recording medium is the first recording medium of the job, herein the initial value of the matching position for the matching shift section  705  is established to a predetermined matching position. Incidentally, the established initial value is stored in a memory M 1  shown in  FIG. 7  (F 2 ). Next, it is recognized whether the mixture mode is established by the first recognition section  801  in F 3 , and when the mixture mode is established (YES), the process proceeds to F 4 , while when the mixture mode is not established (NO), the process proceeds to F 5 . When the mixture mode is established, it is recognized whether the recording medium is the first recording medium of the second or later group by the second recognition section  802  in F 4 , and when the recording medium is the first recording medium thereof (YES), the process proceeds to F 6 , while when it is not the first recording medium thereof, the process proceeds to F 7 . 
     Next, when the mixture mode is not established, it is recognized whether the recording medium is the first recording medium of the second or later group or the first recording medium of the separation by the fourth recognition section  804  in F 5 , and the process proceeds to F 6  when YES, while the process proceeds to F 7  when NO. The established initial value of the matching position is changed in F 6 . In other words, the initial value memorized in the memory M 1  shown in  FIG. 7  is changed (F 6 ). Further, in F 7 , the matching position of the matching shift section is acquired from the memory M 1  shown in  FIG. 7  and recognized according to the recognition result in F 3 , F 4  and F 5  described above (F 7 ). Subsequently, the information about the recognition matching position is sent from the controlling section  800   a  to the controlling section  800   b.    
     Next, the operation of the image forming system of Embodiment 1 is illustrated and described with reference to the above described general configuration, mechanical structure and electrical structure of the image forming system. 
     An example of the case of producing a printing material as two sets (G 1  and G 2 ) relative to a document set, wherein the first and second pages are not finished and the third to tenth pages are applied to finished (stapled) will be described with reference to  FIG. 1  to  FIG. 8 . 
     The document D shown in  FIG. 1  is set in the document feeder  600 , and in the operating section  200 B, stapling is enabled in the basic setting screen  204  shown in  FIG. 2 , the copy number is designated to 2 sets, and offset is enabled. Further, the existence of the finish processing for every page and its position and the other parameters are designated in the page setting screen  205  shown in  FIG. 3 . 
     The recording-medium stacking position information recognized by the set contents of the job is notified to the controlling section  800   b  of the finisher  700 , together with the other paper feeding information, at the paper feeding timing for every recording medium. The finisher  700  temporarily stores the notified paper feeding information (including the recording-medium stacking position information) in the memory M 3 . 
     Herein, when a start button not shown is pressed, the document D is read by the document reader  600  shown in  FIG. 1  and an image formation is carried out. The first and second pages of the first group are fed into the finisher  700  and conveyed to the process tray  706 . The third to tenth pages of the first group are fed into the finisher  700 , stapled by the stapler  704 , and conveyed to the process tray  706 . Subsequently, based on the information about the matching position sent from the controlling section  800   a , the controlling section  800   b  controls the matching shift section  705 E so that the first to tenth pages of the first group on the process tray  706  are at the recording-medium stacking position P 1  and matches the recording-medium bundle position to a position corresponding to P 1  on the process tray  706 . The recording mediums are then ejected at the recording-medium stacking position P 1  of the stacking tray  708  through the ejecting section  720  shown in  FIG. 4(   a ) and  FIG. 4(   b ). 
     Similarly, the first and second pages of the second group are fed into the finisher  700  and conveyed to the process tray  706 . The third to tenth pages of the second group are fed into the finisher  700 , stapled by the stapler  704 , and conveyed to the process tray  706 . Subsequently, based on the information about the matching position sent from the controlling section  800   a , the controlling section  800   b  controls the matching section  705 E, and matches the recording-medium bundle position to a position corresponding to P 2  on the process tray  706  so that the first to tenth pages of the second group are placed at the recording-medium stacking position P 2  on the process tray. The recording mediums are ejected at the recording-medium stacking position P 2  of the stacking tray  708  through the ejecting section  720  (see  FIG. 6(   b )). 
     As described above, with the image forming system of Embodiment 1, non-finished recording mediums and finished recording mediums within a group of recording mediums can be stacked at the same recording-medium stacking position on the stacking tray. The recording-medium stacking position is changeable for every group of recording mediums, so that the separation of every group is easily identifiable. Incidentally, the recognition by the first recognition section, second recognition section and third recognition section allow a simple and reliable control of the recognition of recording-medium stacking positions. With the image forming apparatus, the above described advantage can be achieved by combining with the above described finisher. Further, with the program, a program capable of controlling the image forming system will be realized, and particularly when the mixture mode is established, the image forming system can be controlled so that the non-finished recoding mediums and the finished recording mediums within the group are stacked at the same recording-medium stacking position on the stacking tray. 
     Embodiment 2 
     Next, an image forming system, the mechanical structure, electrical structure and operation of an image forming apparatus, and a program to control the image forming apparatus according to Embodiment 2 will be described. Incidentally, the same reference numerals are assigned to the portions functionally and mechanically similar to Embodiment 1 and the description thereof is partially omitted, and mainly the portions different from those in Embodiment 1 will be described. Further, the general configuration of the image forming system according to Embodiment 2 is structurally similar to Embodiment 1, so that its description will be omitted. 
     Mechanical Structure of Embodiment 2 
     Of the mechanical structure in the image forming system, the operating section of the image forming apparatus, and the matching shift section  705 , ejecting section  720  and stacking tray  708  of the finisher according to the present embodiment will be described in detail. 
     Hereinafter, the description will be made about the operating section  200 B as the operating section similarly to Embodiment 1.  FIG. 9  is a view showing a basic setting screen  206  of the operating section according to Embodiment 2,  FIG. 10  is a view showing a page setting screen  207  of the operating section according to Embodiment 2, and  FIG. 11  is a view showing a page detail setting screen  208  according to Embodiment 2. 
     As shown in  FIG. 9 , the setting for a whole job is established in the basic setting screen  206 . The contents of the setting include the document size, print size, print type (one-sided, two-sided), finish processing (staple, punch and the like), offset ON/OFF, offset ON/OFF for every page, copy number and the like. Offset ON or OFF for the whole job can be designated in the checkbox of “offset”. Further, offset ON or OFF for every page can be established in the checkbox of “page offset”. When the offset checkbox is ON, as shown in the lower part of the basic setting screen  206  of  FIG. 9 , a list is displayed from which a mode can be selected from plural modes of how to offset for every page. More particularly, the setting of “page offset” can be selected and established from a first mode to prohibit offset, a second mode to offset for every group, and a third mode to offset for every subset group. 
     Incidentally, in the embodiment, offset is not carried out in the mixture mode, even if the “offset” check or the “page offset” check is ON, in other words, the default setting is established to control offset to be prohibited in the mixture mode. Incidentally, this setting is changeable by an administrator or a user. It is possible to establish the setting to allow the offset control depending on the mode selected from the first to third modes described below even in the mixture mode by selecting “offset in the mixture mode” and establishing in an offset control setting screen in the mixture mode not shown. 
     Further, the page setting screen  207  shown in  FIG. 10  is displayed when the “page setting” tag at the upper part of the basic setting screen  206  is selected. 
     As shown in  FIG. 10 , when the checkbox of “page setting” is ON in the page setting screen  207 , the enable/disable of the finish processing for every page of subset-staple can be established (when ON, a portion displayed in the list within the frame at the bottom thereof will be enabled). 
     Further, the detail setting of the list described above can be established with three buttons (“Add”, “Edit”, and “Delete”) at the lower part of the screen of the page setting screen  207 . 
     “Add” is a button for carrying out a new addition to the list, “Edit” is a button for selecting an item in the list and editing the setting contents, and “Delete” is a button for selecting an item in the list and deleting the selected item. 
     When “Add” or “Edit” is selected, the page detail setting screen  208  shown in  FIG. 11  which is another form for the setting and input is displayed. 
     The contents of the finish processing such as the detailed page designation and the staple designation can be established in the page detail setting screen shown in  FIG. 11 . Incidentally, the setting of the page detail setting screen  208  of  FIG. 11  has priority over the setting of the page setting screen  207  in  FIG. 10 . 
     Herein, as an example of the setting, the case in which a first group (first set) is a 6-page job, wherein staple is disabled for the first to second pages and subset-staple for the third to sixth pages is designated will be described. At first, staple is set to ON in the basic setting screen  206  of  FIG. 9 , and then staple is set to OFF for the first to second pages in the page detail setting screen  208  of  FIG. 11 . Incidentally, the setting can be established by another setting method in which staple is first set to OFF in the basic setting screen  206  of  FIG. 9  and then staple is set to ON for the third to sixth pages in the page detail setting screen of  FIG. 11 . 
     Next, the description will be made about stacking on the stacking tray  708 . Incidentally, the matching shift section  705  and the ejecting section  720  are mechanically the same as Embodiment 1. 
       FIG. 12(   a ) and  FIG. 12(   b ) are examples of stacking on the stacking tray in the case of prohibiting offset in the mixture mode setting, namely, in the default setting.  FIG. 12(   a ) shows a portion of the configuration of the above described matching shift section  705 , in which the matching shift plates  705   a ,  705   b  are provided. 
       FIG. 12(   b ) shows the stacking state of recording mediums, and more particularly, it shows the stacking state in which non-finished recording mediums S 1 , S 2  and finished recording mediums S 3  to S 6  constitute a first group G 1  which is stacked at a recording-medium stacking position P 3  of the stacking tray  708 , and a second group G 2  is similarly stacked at the same recording-medium stacking position P 3  when the mixture mode is established. Incidentally, the recording medium S 1  is the first recording medium of the job, and this embodiment also shows, similarly to Embodiment 1, an example of a set as an example of a group. 
     Next,  FIG. 13(   a ),  FIG. 13(   b ),  FIG. 13(   c ) and  FIG. 13(   d ) are examples of a stacking on the stacking tray in the case of allowing offset in the mixture mode setting, in other words, in the case in which “offset in the mixture mode” is established through the offset control setting screen in the mixture mode not shown, “page offset” of  FIG. 9  is set to ON and a mode is designated from plural modes.  FIG. 13(   a ) shows the general configuration of the matching shift section  705 ,  FIGS. 13(   b ) to  13 ( d ) show the stacking states of the mode designation examples from the first to third mixture modes, wherein  FIG. 13(   a ) is similar to  FIG. 12(   a ) and the description thereof is omitted. 
     In the first mode, as shown in  FIG. 13(   b ), the non-finished recording mediums S 1 , S 2  and the finished recording mediums S 3  to S 6  constitute the first group G 1  which is stacked at the recording-medium stacking position P 3  of the stacking tray  708 , and the second group G 2  is similarly stacked at the same recording-medium stacking position P 3 . Incidentally, the recording medium S 1  is the first recording medium of the job. 
     In the second mode, as shown in  FIG. 13(   c ), the non-finished recording mediums S 1 , S 2  and the finished recording mediums S 3  to S 6  constitute the first group G 1  which is stacked at the recording-medium stacking position P 1  of the stacking tray  708 , and the second group G 2  is stacked at the recording-medium stacking position P 2 . Incidentally, the recording medium S 1  is the first recording medium of the job and the recording medium S 6  is the last recording medium within the group. 
     In the third mode, as shown in  FIG. 13(   d ), the non-finished recording mediums S 1 , S 2  constitute a sub-group G 1   a  within the first group, and the sub-group G 1   a  is stacked at the recording-medium stacking position P 1 . Further, the finished recording mediums S 3  to S 6  constitute a sub-group G 1   b  within the first group, and the sub-group G 1   b  is stacked at the recording-medium stacking position P 2 . These sub groups G 1   a , G 1   b  constitute the first group G 1 . The same is true in the second group G 2 . Incidentally, the recording medium S 1  is the first recording medium of the job, and the recording mediums S 2 , S 6  and so on are the last recording mediums of the subset groups. 
     Electrical Structure of Embodiment 2 
     Next, the electrical structure blocs and the flow of the program involving the recognition of the recording-medium stacking position according to the present embodiment, will be described in relation to the electrical structure of the image forming system. 
     The electrical structure blocks of the image forming system according to Embodiment 2 are similar to Embodiment 1 and the description thereof is omitted. 
     The image forming system of Embodiment 2 is designed, similarly to the above described Embodiment 1, that the ejection control of recording mediums to the stacking tray  708  is executed by the above described controlling section  800   a  in the image forming apparatus side, wherein the controlling section  800   a  sends its execution result to the controlling section  800   b , and the controlling section  800   b  in the finisher side controls the ejection of the recording mediums based on the information. 
     Further, the controlling section  800   a  recognizes whether the mode is the mixture mode or not based on the finish processing designation which is input in the setup screen of  FIG. 9  and the information of the existence of the page setting which is input in the page setting screen  207  shown in  FIG. 10 . Incidentally the recognition can be made in a manner similar to Embodiment 1. 
     Next, the description will be made about the flow of the program involving the recognition of the recording-medium stacking positions that is executed by the controlling section  800   a  in the image forming system of Embodiment 2. 
     There are two types of flows, a first flow for the case in which offset is always prohibited in the mixture mode setting and a second flow for the case in which the offset setting is designated in the mixture mode, and the both flows will be described respectively. 
     In the controlling section  800   a , the second flow is selected when “offset in the mixture mode” is established, and the first flow is selected in the default setting in the offset control setting screen in the mixture mode not shown. 
     Incidentally, the recording-medium stacking position information recognized in the flow is notified to the controlling section  800   b  of the finisher, together with the other paper feeding information, at the paper feeding timing for every recording medium. The finisher temporarily stores the notified paper feeding information (including the recording-medium stacking position information) in the memory to control the recording-medium stacking position referring to the information at the ejecting timing. 
     At first, the description will be made about the first flow of the case in which offset is always prohibited in the mixture mode setting, in other words, “page offset” is set to ON and the mode is not established.  FIG. 14  is the first flow that recognizes recording-medium stacking positions on the stacking tray  708  according to Embodiment 2. In  FIG. 14 , it is recognized whether the recording medium is the first recording medium of the job by the third recognition section in F 11 , and when it is the first recording medium of the job, the process proceeds to F 12 . While when the recording medium is not the first recording medium of the job, the process proceeds to F 14 . In F 12 , the offset setting information is acquired. In F 13 , the initial value of the recording-medium stacking position (which is assumed to be the recording-medium stacking position P 1  in the embodiment) is recognized and stored in the memory M 3 . In F 14 , the feed paper (recording medium) information is acquired. In F 15 , the recording-medium stacking position information is acquired from the memory M 3 , and the information is set to the feed paper information of an image memory not shown. 
     In F 16 , it is recognized whether the offset designation exists, and when offset is designated, the process proceeds to F 11 , while when offset is not designated, the process ends here. In F 17 , it is recognized whether the mixture mode designation exists by the first recognition section. When the mixture mode is designated, the process proceeds to F 20 , and when the mixture mode is not designated, the process proceeds to F 18 . In F 18 , it is recognized whether the recording medium is the last recording medium within the group by the second recognition section, and when it is not the last recording medium, the process ends here, while when it is the last recording medium, the process proceeds to F 19 , updating the recording-medium stacking position information (updating the recording-medium staking position from P 1  to P 3 ) and storing the updated information in the memory, and then the process ends. In F 20 , the process changes the recording-medium stacking position of the feeding recording medium information to the fixed value (changes the recording-medium stacking position from P 1  to P 3 ) and then ends. 
     Next, the description will be made about the program (second flow) of the case in which “page offset” is ON in the mixture mode and plural modes are designated.  FIG. 15  is the second flow that recognizes recording-medium stacking positions on the stacking tray  708  according to Embodiment 2. In  FIG. 15 , F 21  to F 25  are the same as F 11  to F 15  shown in  FIG. 14  described above and the description thereof is omitted. In F 26 , it is recognized whether the offset designation exists, and when offset is designated, the process proceeds to F 27 , while when offset is not designated, the process ends here. In F 27 , it is recognized whether the mode is the mixture mode, and when it is the mixture mode, the process proceeds to F 29 , while when not the mixture mode, the process proceeds to F 28 . In F 28 , it is recognized whether the recording medium is the last recording medium within the group by the second recognition section, and when it is not the last recording medium, the process ends here, while when the last recording medium, the process updates the recording-medium stacking position information and stores in the memory in F 32 , and then it ends. In F 29 , the offset designation content of the mixture mode is recognized. More particularly, it is recognized which mode is selected among the first mode, the second mode and the third mode. In the case of the first mode which is the offset prohibition designation, the process changes the recording-medium stacking position of the feed recording medium information to the fixed value (P 3 ) in F 31 , and then ends. In F 29 , when the mode is the third mode which is the offset designation for sub-group in the mixture mode, the process proceeds to F 30  in which it is recognized whether the recording medium is the last recording medium of the subset group, and when it is the last recording medium, the process proceeds to F 32 , while when it is not the last recording medium, the process ends here. Further, in F 29 , when the mode is the second mode which is the offset designation for every group, the process proceeds to F 28 . 
     Next, examples of the operations in the cases in which offset is always prohibited in the mixture mode setting and offset is established in the mixture mode setting will be respectively described with reference to the above described mechanical structure and electrical structure, in relation to the operation of the image forming system of Embodiment 2. 
     As an example, the case of producing a printing material relative to a document set as two sets of recording mediums, wherein the first and second pages of the recording mediums are not finished and the third to sixth pages of the recording mediums are finished (stapled) will be described. 
     (The Case in Which Offset is Always Prohibited in the Mixture Mode Setting) 
     The document D shown in  FIG. 1  is set in the document feeder  600 . The job contents are set in the operating section  200 B. More particularly, offset is enabled, stapling is enabled, and the copy number is designated as  2  sets in the basic setting screen  206  shown in  FIG. 9 . Next, the page setting is enabled, and “Add” is selected in the page setting screen shown in  FIG. 10 . Further, 1 Staple is designated and the page number is designated as 3-6 pages in the page detail setting screen  208  shown in  FIG. 11 . 
     The recording-medium stacking position information recognized by the set contents of the job is notified to the controlling section  800   b  of the finisher  700 , together with the other paper feeding information, at the paper feeding timing for every recording medium, and the finisher  700  temporarily stores the notified paper feeding information (including the recording-medium stacking position information) in the memory M 3 . 
     Next, when the start button not shown is pressed, the document D is read by the document reader  600  and the image formation is carried out. The first and second pages of the first group are fed into the finisher  700 . They are conveyed to the process tray  706 . Further, the third to sixth pages of the first group are fed into the finisher  700 , stapled by the stapler  704  and conveyed to the process tray  706 . 
     The controlling section  800   b  recognizes the recording-medium stacking position based on the paper feeding information temporarily stored in the memory M 3 , controlling the matching shift  705 E, matching the recording-medium bundle position to a position corresponding to P 3  on the process tray  706  to eject the recording mediums at the recording-medium stacking position P 3  of the stacking tray  708  through the ejecting section  720 . 
     Similarly, the first and second pages of the second group are fed into the finisher  700  and conveyed to the process tray  706 . Next, the third to sixth pages of the second group are fed into the finisher  700  and stapled by the stapler  704 . The stapled recording mediums are conveyed to the process tray  706 , ejected at the same recording-medium stacking position P 3  of the stacking tray  708  and then stacked as shown in  FIG. 12(   b ). 
     Incidentally, when the mixture mode is not designated, the recording-medium stacking positions are matched on the process tray  706  so that the first group is stacked at the recording-medium stacking position P 1  and the second group is stacked at the recording-medium stacking position P 2 . 
     (The Case of Establishing Offset in the Mixture Mode) 
     The offset selection setting is made by selecting one from the above described “first mode”, “second mode”, and “third mode”. 
     At first, the operation of the “first mode” will be described. 
     The document D shown in  FIG. 1  is set in the document feeder  600 . The job contents are set in the operating section  200 B. More particularly, staple is enabled and the copy number is designated as  2  sets in the basic setting screen  206  shown in  FIG. 9 . Further, offset is enabled, page offset is enabled and the first mode is designated. Page setting is enabled and “Add” is selected in the page setting screen  207  shown in  FIG. 10 . Further, 1 Staple is designated and the page number is designated as 3-6 pages in the page detail setting screen  208  shown in  FIG. 11 . 
     The recording-medium stacking position information recognized by the set contents of the job is notified to the controlling section  800   b  of the finisher  700 , together with the other paper feeding information, at the paper feeding timing for every recording medium. The finisher  700  temporarily stores the notified paper feeding information (including the recording-medium stacking position information) in the memory M 3 . 
     When the start button not shown is pressed, the document D is read by the document reader  600  and the image formation is carried out. The first and second pages of the first group are fed into the finisher  700 . They are conveyed to the process tray  706 . The third to sixth pages of the first group are fed into the finisher  700 , stapled by the stapler  704 , and conveyed to the process tray  706 . The recording-medium stacking position is recognized based on the paper feeding information which is temporarily stored in the memory M 3 , the matching shift  705 E is controlled to match the recording-medium bundle position to a position corresponding to P 3 , and the recording mediums are ejected at the recording-medium stacking position P 3  of the stacking tray  708  through the ejecting section  720 . Similarly, the first and second pages of the second group are fed into the finisher  700 . They are conveyed to the process tray  706 . The third to sixth pages of the second group are fed into the finisher  700  and stapled by the stapler  704 . They are conveyed to the process tray  706 . The recording-medium stacking position is recognized based on the paper feeding information which is temporarily stored in the memory M 3 , the matching shift  705 E is controlled to match the recording-medium bundle position to the position corresponding to P 3  on the process tray  706 , and the recording mediums are ejected at the same recording-medium stacking position of the stacking tray  708  through the ejecting section and then stacked as shown in  FIG. 13(   b ). 
     Next, the operation of the “second mode” will be described. 
     The document D is set in the document feeder  600  shown in  FIG. 1 . The job contents are set in the operating section  200 B. More particularly, stapling is enabled and the copy number is designated as  2  sets in the basic setting screen  206  shown in  FIG. 9 . Further, offset is enabled, page offset is enabled and the second mode is selected. Page setting is enabled and “Add” is selected in the page setting screen  207  shown in  FIG. 10 . Further, 1 Staple is designated and the page number is designated as 3-6 pages in the page detail setting screen  207  shown in  FIG. 11 . 
     The recording-medium stacking position information recognized by the set contents of the job is notified to the controlling section  800   b  of the finisher  700 , together with the other paper feeding information, at the paper feeding timing for every recording medium. The finisher  700  temporarily stores the notified paper feeding information (including the recording-medium stacking position information) in the memory M 3 . 
     When the start button not shown is pressed, the document D is read by the document reader  600  and the image formation is carried out. The first and second pages of the first group are fed into the finisher  700 . They are conveyed to the process tray  706 . The third to sixth pages of the first group are fed into the finisher  700 , stapled by the stapler  704  and conveyed to the process tray  706 . The recording-medium stacking position is recognized based on the paper feeding information which is temporarily stored in the memory M 3 , the matching shift  705 E is controlled to match the recording-medium bundle position to the position corresponding to P 1  on the process tray  706 , and then the recording mediums are ejected at the recording-medium stacking position P 1  on the stacking tray  708  through the ejecting section  720 . Similarly, the first and second pages of the second group are fed into the finisher  700 . They are conveyed to the process tray  706 . The third to sixth pages of the second group are fed into the finisher  700 , and stapled by the stapler  704 . The stapled recording mediums are conveyed to the process tray  706 . The recording-medium stacking position is recognized based on the paper feeding information which is temporarily stored in the memory M 3 , the matching shift  705 E is controlled to match the recording-medium bundle position to the position corresponding to P 2  on the process tray  706 , and then the recording mediums are ejected at the recording-medium stacking position P 2  of the stacking tray  708  through the ejecting section  720  and stacked as shown in  FIG. 13(   c ). 
     Finally, the operation of the “third mode” will be described. 
     The document D is set in the document feeder  600  (see  FIG. 1 ). The job contents are set in the operating section  200 B. More particularly, stapling is enabled and the copy number is designated as  2  sets in the basic setting screen  206  of  FIG. 9 . Further, offset is enabled and the third mode is selected. Page setting is enabled and “Add” is selected in the page setting screen  207  shown in  FIG. 10 . 1 Staple is designated and the page number is designated as 3-6 pages in the page detail setting screen  208  shown in  FIG. 11 . 
     The recording-medium stacking position information recognized by the set contents of the job is notified to the controlling section  800   b  of the finisher  700 , together with the other paper feeding information, at the paper feeding timing for every recording medium. The finisher  700  temporarily stores the notified paper feeding information (including the recording-medium stacking position information) in the memory M 3 . 
     When the start button not shown is pressed, the document D is read by the document feeder  600  and the image formation is carried out. The first and second pages of the first group are fed into the finisher  700 . They are conveyed to the process tray  706 . The matching position is recognized based on the paper feeding information which is temporarily stored in the memory M 3 , the matching shift  705 E is controlled to match the recording-medium bundle position to the position corresponding to P 1  on the process tray  706 , and the recording mediums are ejected through the ejecting section  720  at the recording-medium stacking position P 1  of the stacking tray  708 . The third to sixth pages of the first group are fed into the finisher  700 , stapled by the stapler  704  and conveyed to the process tray  706 . The recording-medium stacking position is recognized based on the paper feeding information which is temporarily stored in the memory M 3 , the matching shift  705 E is controlled to match the recording-medium bundle position to the position corresponding to P 3  on the process tray  706 , and then the recording mediums are ejected at the recording-medium stacking position P 3  on the stacking tray  708  through the ejecting section  720 . Similarly, the first and second pages of the second group are fed into the finisher  700 . They are conveyed to the process tray  706 . The recording-medium stacking position is recognized based on the paper feeding information which is temporarily stored in the memory M 3 , the matching shift  705 E is controlled to match the recording-medium bundle position to the position corresponding to P 1  on the process tray  706 , and then the recording mediums are ejected at the recording-medium stacking position P 1  of the stacking tray  708  through the ejecting section  720 . The third to sixth pages of the second group are fed into the finisher  700  and stapled by the stapler  704 . They are conveyed to the process tray  706 . The recording-medium stacking position is recognized based on the paper feeding information which is temporarily stored in the memory M 3 , the matching shift  705 E is controlled to match the recording-medium bundle position to the position corresponding to P 3  on the process tray  706 , and the recording mediums are ejected at the recording-medium stacking position P 3  of the stacking tray  708  through the ejecting section  720  and then stacked as shown in  FIG. 13(   d ). 
     As described above, with the image forming system of Embodiment 2, when the mixture mode is established, non-finished recording mediums and finished recording mediums within a group of recording mediums can be stacked at the same recording-medium stacking position on the staking tray, so that the recording mediums will be easily taken out all together. When the mixture mode is established, even if the offset designation is established, the non-finished recording mediums and the finished recording mediums within the group of recording mediums can be stacked at the same recording-medium stacking position on the stacking tray, so that the convenience will be improved. 
     In the default setting, when the mixture mode is established, offset is prohibited even if the offset designation is established, so that when further setting the output material of the whole job in an offline finisher or packing it in a box in batch, the user will not need to rearrange the output material. 
     Further, when “offset in the mixture mode” is selected and established in the offset control setting screen in the mixture mode, offset by group and offset by sub-group are allowed even in the mixture mode. Thus, the recording medium bundle can be offset for every user or every job with a separation reflecting the user&#39;s intention, so that the convenience can be improved. 
     Incidentally, the recognitions of the first recognition section, second recognition section and third recognition section allow the simple and reliable control of the recognition of the recording-medium stacking positions. With the image forming apparatus, it will be possible to achieve the above described advantage by combining with the finisher. Further, with the program, a program capable of controlling the image forming system will be realized, and in particular, when the mixture mode is established, the image forming system will be controllable so that the non-finished recoding mediums and the finished recording mediums within the group are stacked at the same recording-medium stacking position on the stacking tray. 
     It is to be understood that Embodiments 1 and 2 were described above, but the invention is not limited to these embodiments, and for example, although the recording-medium stacking position is changed by shifting the recording mediums using the matching shift section of the finisher in the embodiments, the recording-medium stacking position may be changed by shifting the stacking tray itself. The recognition of the boundary of groups may be made by recognizing whether the recording medium is the first recording medium of the second or later group, or by recognizing whether the recording medium is the last recording medium of the group. As for the finish processing for recording mediums, a processing applied to the recording mediums is preferred, and particularly, the finish processing that performs stapling, punching or folding is effectively applied to the embodiments. The mixture mode was described by taking a typical example of the case in which plural non-stapled recording mediums and one stapled bundle are intermingled within the single group, but for example, plural stapled bundles may exist within a single group. Further, Embodiment 1 was described by taking an example of the case in which when the mixture mode is established, the non-finished recording mediums and the finished recoding mediums within the group are stacked at the same recording-medium stacking position on the stacking tray, and the recording-medium stacking position is shifted to two places in the front side and the back side as seen from the front of the image forming system, but for example, the recording-medium stacking position may be switched to three or more places. 
     According to the above embodiments, the following effects can be attained. 
     Since the non-finished recording medium and the finished recording medium within the single group are stacked at the same recording-medium stacking position on the stacking tray if the mixture mode is set, it becomes possible to easily take out the recording mediums of a group, even if the mixture mode is set. 
     It becomes possible to change the recording-medium stacking position for every group of recording mediums too. Accordingly, it is possible to easily recognize each boundary of the group, even if the mixture mode is established. 
     It becomes possible to set the recording-medium stacking positions of the plural groups of all printing materials at the same position within the stacking tray. Accordingly, it becomes possible to easily take out the plural groups as a single unity, and to easily pack them into a box after taking out them from the stacking tray. 
     Even if the mixture mode is set, it becomes possible to select any one of the first mode, the second mode and the third mode depending on the usage, resulting in an improvement of usability. 
     While the mixture mode is set, the non-finished recording medium and the finished recording medium in the same group can be stacked at a same recording-medium stacking position within the stacking tray, even if a change command of the recording-medium stacking position is set. Accordingly, it is possible to simplify the taking-out operation, even if the recording-medium stacking position is already set irrespective of the user&#39;s intention. 
     It becomes possible to surely control the recording-medium stacking position, simply based on the recognition results outputted by both the first recognition section and the second recognition section. 
     It becomes possible to surely control the recording-medium stacking position, simply based on the recognition result of the first recognition section, the recognition result of the second recognition section and the recognition result of the third recognition section. 
     If handling recording mediums, which are ejected from the image forming apparatus and to which various kinds of processing, such as a staple processing, a punching processing, etc., are to be applied, the present embodiments can be more effectively implemented. 
     Since a number of the plural groups corresponds to a number of sets of the plural printing materials to be produced from the single document set, the abovementioned effects are exhibited within this number of the plural printing materials. 
     While the preferred embodiments of the present invention have been described using specific term, such description id for illustrative purpose only, and it is to be understood that changes and variations may be made without departing from the spirit and scope of the appended claims.