Abstract:
An image forming apparatus has a plurality of paper feed units setting index sheets. A storage section stores size information and index number information indicating the number of index sheets per set of paper sheet set in each paper feed unit, and a control section automatically changes the paper feed unit to be used from a first paper feed unit to a second paper feed unit and does not automatically change the paper feed unit to a third paper feed unit when the index sheets in the first paper feed unit are exhausted, the size information and the index number information of the first paper feed unit coinciding with those of the second paper feed unit and at least one of the size information and the index number information of the first paper feed unit not coinciding with those of the third paper feed unit.

Description:
FIELD OF THE INVENTION 
   The present invention relates to an image forming apparatus which functions as a printing apparatus, such as a printer, copying apparatus, facsimile apparatus, or multifunction apparatus of them and, more particularly, to an image forming apparatus capable of selectively supplying a paper sheet from any one of a plurality of paper feed portions and printing on it, and a control method therefor. 
   BACKGROUND OF THE INVENTION 
   Widely spread image forming apparatuses such as a copying apparatus, printer, and facsimile apparatus have a paper storage portion (paper feed stage or paper feed portion) such as a cassette or tray which stores print sheets. Such image forming apparatus forms an image on a paper sheet supplied from the paper storage portion, and discharges the paper sheet outside the image forming apparatus. In order to form images on various paper sheets, some image forming apparatuses have a plurality of paper storage portions and can store paper sheets of various sizes and various types in the respective paper storage portions. At present, image forming apparatuses which store many paper sheets of a specific size by storing paper sheets of the same size in a plurality of paper feed stages, and form many images by one paper replenishment have become popular. 
   An image forming apparatus which stores paper sheets of the same size in a plurality of paper feed stages has an auto cassette change (hereinafter referred to as ACC) function of, when all paper sheets in a paper storage portion are consumed but paper sheets of the same paper size are stored in another paper storage portion, keeping feeding paper sheets from the substitute paper storage portion without stopping paper feed operation. Even if paper sheets in a given cassette run out, paper sheets in another cassette can be successively used. This shortens the operation stop time due to the absence of paper sheets, and increases the availability and productivity of the image forming apparatus (see Japanese Patent Laid-Open No. 2002-40881). 
   Japanese Patent Laid-Open No. 2002-40881 also discloses an image forming apparatus which considers the paper type in addition to the paper size. The image forming apparatus determines whether a paper storage portion storing paper sheets of the same size and same paper type as paper sheets which run out is available and, when no such paper storage portion, the auto cassette change for paper sheets which run out is not performed. 
   There is also proposed an image forming apparatus which stores paper sheets called index sheets (tabbed sheets) in the paper storage portion of the image forming apparatus, which may form images (see Japanese Patent Laid-Open No. 8-73110). As disclosed in Japanese Patent Laid-Open No. 8-73110, an index sheet (tabbed sheet) has an index (tab) added to a normal rectangular paper sheet. In general, index positions sequentially shift, the sheets overlap each other, and a plurality of index sheets form one set. The number of index sheets which form one set will be called a division number in this specification. Some image forming apparatuses which feed and deliver index sheets have a function of automatically discharging excessive index sheets out of a bundle of index sheets of one set from the paper storage portion outside the apparatus (see Japanese Patent Laid-Open No. 2002-3063). 
   A printed index sheet is set on a post-processing device called an inserter or collator in a copying apparatus or printer. The index sheet is inserted at a designated position of a printed or copied document, or manually inserted into a document. While a document is printed or copied on normal paper sheets, an index sheet may be conveyed to a designated insertion position from a paper storage portion which supports the index sheet, subjected to printing, and then merged into the printed or copied document. 
   When a paper storage portion whose paper size and paper type coincide with those of a paper storage portion which runs out of paper sheets is designated as the change destination of the ACC function, as disclosed in Japanese Patent Laid-Open No. 2002-40881, an image forming apparatus which feeds index sheets, as disclosed in Japanese Patent Laid-Open No. 2002-3063, performs auto cassette change even with a different index number (division number) of index sheets. Particularly, an index sheet is larger in width by the index than a normal paper sheet. Index sheets may not be stored in a normal paper feed stage, and can only be stored in a limited paper feed stage. 
   For example, in an image forming apparatus shown in  FIG. 2 , cassettes  311  and  312  are paper feed stages which can store many paper sheets but cannot store index sheets. Cassettes  313  and  314  are paper feed stages which can store a smaller number of paper sheets, compared to the cassette  311 , but can store even index sheets. In this case, a user who uses many index sheets can store index sheets in both the cassettes  313  and  314 , perform auto cassette change between index sheets, and use the index sheets. When, for example, the cassette  313  stores index sheets with an index number (division number) of 4 and the cassette  314  stores index sheets with an index number (division number) of 5, these index sheets are of originally different paper types, and auto cassette change between these cassettes is not intended by the user. In this case, it is preferable not to perform auto cassette change. 
   When index sheets with an index number of 4 are stored in both the cassettes  313  and  314 , auto cassette change is preferably performed because of the same index number. 
   SUMMARY OF THE INVENTION 
   The present invention has been made in consideration of the above situation, and has as its object to provide an image forming apparatus which does not perform auto paper feed portion change when the coidentity of index sheets is not held before and after automatic paper feed portion change in printing on an index sheet, for example, when sizes, index numbers, or the shapes of index portions do not coincide with each other, and a control method therefor. 
   To achieve the above object, the present invention has the following arrangement. 
   According to the present invention, an image forming apparatus having a plurality of paper feed portions capable of setting index sheets, comprises 
   a storage section which stores predetermined information on a paper sheet set in each paper feed portion; and 
   a control section which performs processing of automatically changing the paper feed portion between the plurality of paper feed portions on the basis of the predetermined information stored in the storage section, 
   wherein when index sheets are set in the plurality of paper feed portions and pieces of predetermined information on the index sheets set in the paper feed portions coincide with each other, said control section controls the paper feed portions so as to perform change processing between the plurality of paper feed portions in which index sheets are set, and when the pieces of predetermined information do not coincide with each other, controls the paper feed portions so as not to perform change processing. 
   According another aspect of the present invention, the predetermined information stored in said storage section preferably includes information on a size and a type of the paper sheet set in the paper feed portion, and when the paper type is an index sheet, information on the number of index portions and/or a shape of the index portion is further stored. 
   According another aspect of the present invention, the apparatus further comprises an index sheet setting section which sets the information on the number of index portions and/or the shape of the index portion. 
   According another aspect of the present invention, the image forming apparatus further comprises a paper feed portion change setting section which sets whether to automatically enable paper feed portion change processing for each of the plurality of paper feed portions, and when the paper feed portion change setting section performs a setting which permits paper feed portion change processing for the paper feed portions in which the index sheets are set, but the pieces of predetermined information on the index sheets set in the plurality of paper feed portions are determined not to coincide with each other, the control section controls the paper feed portions so as not to perform change processing. 
   Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
       FIG. 1  is a view for explaining the whole configuration of an image input/output system according to an embodiment; 
       FIG. 2  is a sectional view showing a reader section and printer section; 
       FIG. 3  is a view showing an operation section; 
       FIG. 4  is a block diagram showing a control section; 
       FIG. 5  is a chart showing a communication sequence between a control section  110  and a reader section  200 ; 
       FIG. 6  is a chart showing a communication sequence between the control section  110  and a printer section  300 ; 
       FIG. 7  is a view for explaining paper storage portions  311 ,  312 ,  313 , and  314 ; 
       FIG. 8  is a view showing a user mode window; 
       FIG. 9  is a view showing a common specification setting window (1/4); 
       FIG. 10  is a view showing a common specification setting window (2/4); 
       FIG. 11  is a view showing an auto cassette change ON/OFF window; 
       FIG. 12  is a view showing an auto cassette change ON/OFF &amp; copying selection window; 
       FIG. 13  is a view showing a paper type registration window; 
       FIG. 14  is a view showing the second paper type registration window; 
       FIG. 15  is a view showing a paper type registration window and index sheet setting; 
       FIGS. 16A and 16B  are flow charts showing the operation of the control section (controller)  110  according to the present invention; 
       FIG. 17  is a view for explaining ACC for paper sheets with different index numbers; and 
       FIG. 18  is a view for explaining ACC for paper sheets with the same index number. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The whole configuration of an image input/output system according to an embodiment of the present invention will be described with reference to  FIG. 1 . The embodiment will exemplify a copying apparatus which can be utilized as a printer and scanner, i.e., a so-called multifunction apparatus. The present invention can also be applied to a printer, facsimile apparatus, or simple copying apparatus as far as the printing apparatus has a plurality of paper feed cassettes or paper feed trays. 
   &lt;Arrangement of Image Forming Apparatus&gt; 
   In  FIG. 1 , a reader section (image input apparatus)  200  optically reads an original image, and converts it into image data. The reader section  200  comprises a scanner unit  210  having a function of reading an original and an original feed unit  250  having a function of conveying an original sheet to the scanner unit  210 . 
   A printer section (image forming apparatus)  300  conveys a print sheet, prints image data as a visible image on the print sheet, and delivers the print sheet outside the apparatus. The printer section  300  comprises a paper feed unit  310  having a plurality of types of print sheet cassettes, a marking unit  320  having a function of transferring and fixing image data onto a print sheet, and a delivery unit  330  having a function of outputting a printed print sheet outside the apparatus. In the embodiment, the whole multifunction apparatus will be called an image input/output system, and the printer section serving as an image forming function will be called an image forming apparatus. In this sense, the image forming apparatus is not limited to the multifunction apparatus of the embodiment, and is also incorporated in a facsimile apparatus, printer apparatus, or the like. 
   A control section (controller)  110  is electrically connected to the reader section  200  and printer section  300 . The control section  110  is further connected to host computers  401  and  402  via a network  400 . 
   The control section  110  controls the reader section  200  to load original image data, and controls the printer section  300  to form an image on a print sheet on the basis of image data, providing a copying function. The control section  110  also provides a scanner function of converting image data read by the reader section  200  into code data and transmitting the code data to a host computer via the network  400 , and a printer function of converting code data (page description language: PDL) received from the host computer via the network  400  into image data and outputting the image data to the printer section  300 . 
   The PDL defines a command representing a page break for each language. For example, the PDL defines a command “ShowPage” for PostScript available from Adobe Systems and a command “FormFeed” for PCL available from Hewlett-Packard. When such command is sent, the break of one page is first detected. There is also a method of determining the end of a job from time-out after interruption of data transfer from a host computer. 
   An operation section  150  is connected to the control section  110  and formed by a liquid crystal touch panel, and provides a user I/F for operating the image input/output system. 
     FIG. 2  is a sectional view showing the reader section  200  and printer section  300 . The original feed unit  250  of the reader section feeds original sheets one by one from the first page onto a platen glass  211 . At the end of original reading operation, an original sheet on the platen glass  211  is discharged to a discharge tray  219 . When an original sheet is conveyed onto the platen glass  211 , a lamp  212  is turned on, and movement of an optical unit  213  starts to expose and scan the original sheet. Light reflected by the original sheet is guided to a CCD image sensor (to be referred to as a CCD hereinafter)  218  via mirrors  214 ,  215 , and  216  and a lens  217 . The scanned original image is read by the CCD  218 . Image data output from the CCD  218  undergoes predetermined processing, and is transferred to the control section  110 . The reader section  200  comprises of an original detection sensor (not shown), and detects the presence/absence of an original by the original detection sensor. The original detection sensor is formed by a sensor with a lever or an optical sensor. 
   The control section  110  and reader section  200  exchange commands shown in  FIG. 5 . The control section  110  issues “original feed execution request” ( 8001 ) to the reader section  200  in order to feed a set original. After the reader section  200  feeds an original in response to this, the reader section  200  issues “original feed end status notification” ( 8002 ) to the control section  110 . At this time, the reader section  200  detects whether an original exists on the original detection sensor. If an original exists on the original detection sensor, the reader section  200  notifies the control section  110  of “next original exists”; otherwise, “no next original exists”. That is, the presence/absence of an original is detected upon “original feed execution request” ( 8001 ), and the presence/absence of the next original is detected upon “original feed end status notification” ( 8002 ). 
   The control section  110  issues “scan execution request” ( 8003 ) to the reader section  200  to request reading of an original image. The reader section  200  notifies the control section  110  of “scan execution preparation end notification” ( 8004 ) at the start of actual image reading, and “scan end status notification” ( 8005 ) at the end of image reading. 
   A laser driver  321  of the printer section  300  drives a laser emission portion  322 . The laser driver  321  causes the laser emission portion  322  to emit a laser beam corresponding to image data output from the control section  110 . The laser beam irradiates a photosensitive drum  323 , and a latent image corresponding to the laser beam is formed on the photosensitive drum  323 . A developer mix from a developing unit  324  is attracted to the latent image portion of the photosensitive drum  323 . 
   As paper storage portions, the printer section comprises pullout cassettes  311 ,  312 ,  313 , and  314 , and a manual paper feed portion  315  serving as a tray exposed outside the apparatus. In general, a cassette except the manual paper feed portion  315  is pulled out, replenished with paper sheets, and closed, thereby replenishing, storing, and setting paper sheets. 
     FIG. 7  is a view showing the paper feed mechanism of the cassette  311 . The paper storage cassette  311  comprises a cassette opening/closing sensor  1201  which detects the open/closed state of the cassette, a paper feed roller  1202  for feeding a paper sheet, a separation roller  1203  which separates a paper sheet so as not to feed a plurality of paper sheets, a convey roller  1204  which conveys a separated paper sheet to a convey path, a paper feed sensor  1208  which detects whether paper feed is successful, a lifter  1205  which lifts a paper sheet, a lift position detection sensor  1206  which detects a lift-up position, and a paper detection sensor  1207  which detects whether a paper sheet exists. If the paper detection sensor  1207  detects “no paper sheet exists” in each cassette, the detected state is transmitted to the control section  110 , which will be described later. 
   Similar to the cassette  311 , the paper storage portions, i.e., the cassettes  312 ,  313 , and  314  and the manual paper feed portion  315  have the arrangement shown in  FIG. 7 . At the manual paper feed portion  315 , the paper feed sensor  1208  and paper detection sensor  1207  can also be formed by one sensor. In the use of a size sensor, the control section  110  is notified of the size of paper sheets stored in each paper storage portion without any user designation. 
   At a timing synchronized with the start of laser beam irradiation (i.e., a timing uniquely determined using the laser beam irradiation start timing as a reference), a print sheet is sent to a transfer portion  325  via a convey path  331  from any one of the cassettes  311 ,  312 ,  313 , and  314  and the manual paper feed stage  315 . A developer mix deposited on the photosensitive drum  323  is transferred to the conveyed print sheet. The print sheet on which the developer mix is transferred is conveyed to a fixing portion  327  by a convey belt  326 . The developer mix is fixed onto the print sheet by the heat and pressure of the fixing portion  327 . The print sheet having passed through the fixing portion  327  is discharged onto a discharge tray  328  via convey paths  335  and  334 . When the printed surface is reversed and the print sheet is discharged, the print sheet is guided to convey paths  336  and  338 , then conveyed in an opposite direction, and conveyed via a convey path  337  and the convey path  334 , thereby reversing the printed surface. 
   When double-sided printing is set, the print sheet having passed through the fixing portion  327  is guided from the convey path  336  to a convey path  333  by a flapper  329 . The print sheet is conveyed in an opposite direction, and conveyed via the convey path  338  and a refeed convey path  332  by the flapper  329 . The print sheet guided to the refeed convey path  332  passes through the convey path  331  at the above-mentioned timing, and is conveyed to the transfer portion  325 . The print sheet discharged from the convey path  334  is stacked on the discharge tray  328 . 
     FIG. 6  is a chart schematically showing communication between the control section (controller)  110  and the printer section (printer engine)  300  shown in  FIG. 1 . These communication timings are merely an example, and the control section  110  and printer section  300  properly communicate with each other so as to practice the present invention. 
   To print one page, the control section  110  issues a printing preparation request  9001  to the printer section  300 . The printer section  300  which has received the printing preparation request starts pre-printing processing such as temperature control of the fixing unit or cleaning. Upon the completion of pre-printing processing, the printer section  300  issues a printing preparation status  9002  representing the completion of pre-printing processing to the control section  110 . 
   To request feed of a paper sheet, the control section  110  which has received the printing preparation status  9002  issues a printing execution request  9003  to the printer section  300 . At this time, the control section  110  notifies the printer section  300  which of the cassettes  311 ,  312 ,  313 , and  314  and the manual paper feed portion  315  feeds a paper sheet, or when the apparatus has a plurality of discharge trays (not shown in the embodiment), which of the discharge trays receives a discharged paper sheet. 
   The printer section  300  which has received the printing execution request  9003  starts feeding a paper sheet. After the trailing end of a fed paper sheet is detected by a sensor (sensor corresponding to the paper feed sensor  1208  in  FIG. 7 ) mounted at a paper storage portion which feeds the paper sheet, the printer section  300  issues a paper feed result status  9004  to the control section  110 . When an error such as the absence of a paper sheet occurs, the printer section  300  notifies the control section  110  of the error by the paper feed result status  9004 . 
   When the paper sheet reaches a predetermined position, the printer section  300  which has fed the paper sheet issues printing start permission (printing start preparation completion  9005 ). When an image becomes actually formable, the control section  110  which has received the printing start permission (printing start preparation completion  9005 ) from the printer section  300  issues a printing execution request  9006  to the printer section  300 , thereby requesting formation and fixing of the image. After that, hard signal synchronization of image data is performed between the control section  110  and the printer section  300  (the control section  110  transmits image data to the printer section  300  in synchronism with a pixel clock signal transmitted from the printer section  300  to the control section  110 ), thereby forming and fixing the image. 
   The printer section  300  issues a printing result status  9007  to the control section  110  for single-sided printing at a timing when the paper sheet bearing the image is discharged outside the apparatus after fixing and stacked on the discharge tray  328  designated by the printing execution request  9003 , or for double-sided printing at a timing when single-sided printing is completed. 
   When the paper sheet is discharged outside the discharge tray  328  and no subsequent output image exists, the control section  110  issues a printing end notification  9008  to the printer section  300 , and if necessary, requests the printer section  300  to execute post-printing processing (stapling, sorting, or the like). 
   The operation section  150  will be explained with reference to  FIG. 3 . 
   An LCD touch panel  600  allows performing main mode setting operation, status display, and the like. Various settings of an index sheet (to be described later) are also done on the touch panel  600 . A ten-key pad  601  is used to input numerical values of 0 to 9. An ID key  602  is used to input a department number and password code when use limitations based on the department number are posed on the apparatus. 
   A reset key  603  is used to reset a set mode. A guide key  604  is used to display an explanatory window for each mode. A user mode key  605  is used to enter a user mode window. An interrupt key  606  is used to perform interrupt operation. 
   A start key  607  is used to start operation. A stop key  608  is used to stop a job in progress. 
   When a soft power switch  609  is pressed, the backlight of the LCD  600  is turned out, and the apparatus shifts to a low-power state. When a power saving key  610  is pressed, the apparatus shifts to a power saving state, and when the key  610  is pressed again, returns from the power saving state. 
   Function keys  611  and  612  are function switching keys for shifting to a copying function and box function. In  FIG. 3 , the standard window of the copying function is displayed. By pressing the key  612 , the standard window of each function is displayed. 
   An adjustment key  614  is used to adjust the contrast of the LCD touch panel  600 . 
   By pressing a counter confirmation key  615 , a count window which displays the count of copied sheets used is displayed on the LCD  600 . 
   An LED  616  represents printing in execution and image accumulation in the image memory (not shown) of the apparatus. An error LED  617  represents the error state of the apparatus such as a jam or a door open state. A power LED  618  represents that the main switch (not shown) of the apparatus is ON. 
   &lt;Description of Control Section&gt; 
   The functions of the control section  110  will be described with reference to the block diagram shown in  FIG. 4 . The control section  110  to be described later has an illustrative arrangement for explaining the embodiment, and can take any proper arrangement so as to practice the present invention. 
   A main controller  111  is mainly comprised of a CPU  112 , a bus controller  113 , and various I/F controller circuits. 
   The CPU  112  and bus controller  113  control the entire operation of the control section  110 . The CPU  112  is a processor for executing a program or the like loaded from a ROM  114  via a ROM I/F  115 . Operation of interpreting PDL (Page Description Language) code data received from a host computer and expanding the data into raster image data is also described in a program stored in the ROM  114 . Such data is processed by executing this program. The bus controller  113  controls transfer of data input/output to/from each I/F. The bus controller  113  arbitrates contention of data transfer, and controls DMA data transfer. 
   A DRAM  116  is connected to the main controller  111  via a DRAM I/F  117 . The DRAM  116  is used as a work area for various programs to be processed by the CPU  112 , and as an area for accumulating image data. 
   A network controller  121  is connected to the main controller  111  via an I/F  123 . The network controller  121  is connected to an external network via a connector  122 , and controls data exchange with the external network. A general example of the external network is an Ethernet®. 
   A general-purpose high-speed bus  125  is connected to an expansion connector  124  for connecting an expansion board, and an I/O controller  126 . A general example of the general-purpose high-speed bus is a PCI bus. 
   The I/O controller  126  is equipped for two channels with a start-stop synchronous serial communication controller  127  for exchanging control commands with each CPU arranged in the printer section  300 . The serial communication controller  127  is connected to external I/F circuits  140  and  145  via an I/O bus  128 . 
   A panel I/F  132  is connected to an LCD controller  131 . The panel I/F  132  is formed by an I/F for display on the LCD touch panel  600  of the operation section  150 , and a key input/output I/F  130  for controlling input/output of hard keys and touch panel keys. 
   A signal input from the touch panel or hard key of the operation section  150  is transmitted to the CPU  112  via the panel I/F  132 . The LCD touch panel  600  displays image data sent from a panel I/F  520 . 
   A real-time clock module  133  is used to update and save a date and time managed in the apparatus. The real-time clock module  133  is backed up by a backup battery  134 . 
   An E-IDE interface  161  is used to connect an external memory device. A hard disk drive, CD-ROM drive, or the like is connected via this I/F to allow writing and loading programs and image data. 
   Connectors  142  and  147  are respectively connected to the reader section  200  and printer section  300 . The connectors  142  and  147  are formed by start-stop synchronous serial I/Fs ( 143  and  148 ) and video I/Fs ( 144  and  149 ). 
   The scanner I/F  140  is connected to the reader section  200  via the connector  142  and to the main controller  111  via a scanner bus  141 . The scanner I/F  140  has a function of, among others, optimizing an image received from the reader section  200  in accordance with the contents of processing in a subsequent process. The scanner I/F  140  also has a function of outputting to the main controller  111  via the scanner bus  141  a control signal generated on the basis of a video control signal sent from the reader section  200 . 
   Data transfer from the scanner bus  141  to the DRAM  116  is controlled by the bus controller  113 . 
   The printer I/F  145  is connected to the printer section  300  via the connector  147  and to the main controller  111  via a printer bus  146 . The printer I/F  145  has a function of performing smoothing processing for image data output from the main controller  111  and outputting the resultant data to the printer section  300 . The printer I/F  145  also has a function of outputting to the main controller  111  via the printer bus  146  a control signal generated on the basis of a video control signal sent from the printer section  300 . 
   Transfer of raster image data expanded in the DRAM  116  to the printer section  300  is controlled by the bus controller  113 . The expanded data is DMA-transferred to the printer section  300  via the printer bus  146  and video I/F  149 . 
   &lt;User Operation and Corresponding Operation&gt; 
   A means for setting whether to enable automatic paper feed portion change for each paper feed portion in the image forming apparatus according to the present invention, a means for setting a paper type for each paper feed portion, and a means for setting an index number when the paper type is an index sheet will be explained with reference to  FIGS. 8 to 18 . 
   (Selection of User Mode) 
     FIG. 8  is a view showing a window displayed on the liquid crystal screen of the operation section  150  when the user mode key  605  shown in  FIG. 3  is pressed. 
   The user mode window has several selection buttons for various settings. For example, as for an item which must be set commonly between apparatuses, the user selects a common specification setting button  1301  to interactively perform setting. In addition, the user mode window includes a timer setting button for changing to a window having setting items for setting the time or the like when the apparatus shifts to the power saving mode, an adjustment/cleaning button for changing to a window having setting items and the like for adjusting a position such as a staple position, a report output button for changing to a window having setting items and the like for printing out an apparatus state, a system management setting button for changing to a window having items and the like for performing network settings, a copying use setting button for changing to a setting window having setting items and the like associated with a copying-unique function, a transmission/reception specification setting button for changing to a setting window having setting items and the like for a facsimile or Internet facsimile, a box specification setting button for changing to a setting window having setting items associated with, e.g., a box function of storing, in the memory of the apparatus, scanned image data or print data transmitted from a host computer serving as an information processing apparatus, and a destination cover sheet setting button for registering in advance the transmission destination of the above-mentioned facsimile or Internet facsimile. The user mode window also has a close button  1302  for closing the window of  FIG. 8  and changing to a previous window. 
   (Common Specification Settings) 
     FIG. 9  is a view showing a common specification setting window displayed on the liquid crystal screen of the operation section  150  in response to the click of the common specification setting button  1301  in the user mode window shown in  FIG. 8 . 
   The common specification setting window displays buttons and the like for selecting setting items associated with the whole apparatus regardless of copying, printer, box, and facsimile functions. One window displays buttons corresponding to setting items of five types (in  FIG. 9 , “initial function setting button”, “function button after auto clear”, “buzzer ON/OFF button”, “inch input button”, and “auto cassette change ON/OFF button  1402 ”). To select a setting item button other than currently displayed buttons, a next window selection button  1401  is selected. A display “1/4” on the right to the next window selection button  1401  means that four windows exist for common specification settings and the first window is currently displayed. The common specification setting window also has a close button  1403  for closing the window and changing to a window before the common specification setting window, similar to the description of  FIG. 8 . 
     FIG. 10  is a view showing the second common specification setting window displayed on the liquid crystal screen of the operation section  150  in response to the click of the next window selection button  1401  in the common specification setting window shown in  FIG. 9 . 
   The common specification setting window in  FIG. 10  has a “paper type registration button”  1503  for registering a paper type (plain paper, recycled paper, colored paper, OHP, index sheet, or the like) stored in each paper feed portion, a “power saving mode change button” for changing the power saving mode, a “sleep power consumption button” for setting power consumption during sleep, and when a plurality of discharge trays exist, a “dedicated tray setting button” for setting a discharge tray to which a paper sheet bearing an image is discharged for each job type (copying, box, print, facsimile, or the like). The common specification setting window also has a next window selection button  1501  serving as a button for displaying a window for displaying a button associated with the common specification setting items of the next window, similar to the next window setting button shown in  FIG. 9 , and a previous window selection button  1502  for displaying a previous window (the window of  FIG. 9  for the window of  FIG. 10 ). A display “2/4” on the right to the next window selection button  1501  means that four windows exist for common specification settings and the second window is currently displayed. The common specification setting window also has a close button  1504  for closing the window and changing to a window before the common specification setting window, similar to the description of  FIG. 9 . 
   (Designation of Auto Cassette Change) 
     FIG. 11  is a view showing an auto cassette change ON/OFF window displayed on the liquid crystal screen of the operation section  150  in response to the click of the auto cassette change (ACC: =automatic paper feed portion change function described above) ON/OFF button  1402  in the common specification setting window (1/4) shown in  FIG. 9 . The auto cassette change ON/OFF window displays setting items for selecting a paper feed portion which can be automatically selected by the image forming apparatus for each job type (copying, printer, box, print, facsimile, or the like). 
   In the example of  FIG. 11 , buttons for respective job types are displayed. For example, this window has a copy button  1601  for setting a paper feed portion which can be automatically selected for the copying function, a printer button  1602  for setting a paper feed portion which can be automatically selected for the printing function, a box button  1603  for setting a paper feed portion which can be automatically selected for the box function, a reception button  1604  for setting a paper feed portion which can be automatically selected for the facsimile or Internet facsimile function, and another button  1605  for setting a paper feed portion which can be automatically selected for a job not included in the above-described job types. This window also has a close button  1606  for closing the current auto cassette change ON/OFF window and changing to the common specification setting window. 
     FIG. 12  is a view showing a paper type registration window for a copying job displayed on the liquid crystal screen of the operation section  150  in response to the click of the copy button  1601  which allows the user to designate a paper feed portion selectable by the control section  110  for a copying job in the auto cassette change ON/OFF window shown in  FIG. 11 . 
   Icons  1701  to  1705  formed by symbols and characters represent set paper types (displayed by symbols) and paper sizes (displayed by standards) for the pullout cassettes  311 ,  312 ,  313 , and  314  serving as paper storage portions in the printer section  300 , and the manual paper feed portion  315  serving as a tray exposed outside the apparatus. The icon  1701  represents a paper type and paper size set for the manual paper feed portion  315 . In the example of  FIG. 12 , no setting is registered. 
   The icon  1702  represents a paper type and paper size set for the cassette  311 . In the example of  FIG. 12 , LTR-size plain paper is registered as a paper type. The icon  1703  represents a paper type and paper size set for the cassette  312 . In the example of  FIG. 12 , B5-size plain paper is registered. The icon  1704  represents a paper type and paper size set for the cassette  313 . In the example of  FIG. 12 , an A4-size index sheet is registered. The icon  1705  represents a paper type and paper size set for the cassette  314 . In the example of  FIG. 12 , an A4-size index sheet is registered. 
   An ON/OFF button representing whether each paper feed portion is selected as an auto cassette change candidate (ON) or not (OFF) is displayed on the right of the display (each of the icons  1701  to  1705 ) representing a paper size and paper type set for the paper feed portion. For example, an OFF button  1710  is selected for the icon  1701  corresponding to the manual paper feed portion  315 . This means that the manual paper feed portion  315  is not designated as an auto cassette change target for a copying job. Either the OFF or ON button is selected. When the OFF button is selected, no ON button is selected; when the ON button is selected, no OFF button is selected. 
   ON buttons  1711 ,  1712 ,  1713 , and  1714  are selected for the icons  1702 ,  1703 ,  1704 , and  1705  corresponding to the paper feed cassettes  311 ,  312 ,  313 , and  314 . This means that the paper feed portions (cassettes  311  to  314 ) are designated as auto cassette change targets for a copying job. 
   For jobs other than a copying job, the window of  FIG. 12  is similarly displayed by clicking a button representing a job type in the window of  FIG. 11 . A cassette subjected to auto cassette change in print-out can be designated by the above-described procedures. 
   A “paper type consideration button”  1715  in  FIG. 12  further allows the user to designate conditions in selecting a paper feed portion subjected to auto cassette change. 
   The “paper type consideration button ( 1715 )” is used to set whether to consider the paper type in auto cassette change. Whether to consider the paper type in auto cassette change can be designated for each job type. When consideration of the paper type in auto cassette change is designated for a given job, whether not only paper sizes but also paper types coincide with each other (or compatible) is determined in auto cassette change. If both paper sizes and paper types coincide with each other, the paper feed portion is changed. For example, when plain paper sheets in a paper feed portion used by a given job run out, paper sheets equal in size to those in the paper feed portion are stored in another paper feed portion, but the paper type of this paper feed portion is not plain paper, no paper feed operation is done from this paper feed portion. 
   When consideration of the paper type in auto cassette change is not designated for a given job, no paper type is considered in auto cassette change. In this case, the paper feed portion is changed if paper sizes before and after cassette change coincide with each other. 
   When an OK button  1708  is clicked, a cassette subjected to auto cassette change and whether to consider the paper type, which are designated in the above manner, are designated by, for example, an identifier representing the cassette, and stored in the control section  110  for each job. A paper size is detected by a size sensor, and the detected size is stored in the control section  110  for each cassette. Alternatively, a paper size may be designated by the user for each cassette. When a cancel button  1707  is clicked, the window returns to a previous one without registering the above-mentioned settings in the window. 
   If paper sheets run out in printing and the auto cassette change function is to be performed, the control section  110  refers to, among others, the identifiers of cassettes serving as change destinations in accordance with the type of job in execution, and refers to the sizes of paper sheets set in cassettes corresponding to the identifiers. The control section  110  compares paper sizes corresponding to these paper feed portions with a paper size corresponding to the paper feed portion which runs out of paper sheets. 
   When consideration of the paper type is designated, the control section  110  determines whether a paper type corresponding to a paper feed portion determined to have the same paper size and a paper type corresponding to the paper feed portion which runs out of paper sheets are compatible. This sequence will be explained in more detail later. Note that the paper type is set as follows. 
   (Registration of Paper Type) 
     FIG. 13  is a view showing a paper type registration window displayed on the liquid crystal screen of the operation section  150  in response to the click of the paper type registration button  1503  in the common specification setting window (2/4) shown in  FIG. 10 . 
   The paper type registration window displays buttons corresponding to the pullout cassettes  311 ,  312 ,  313 , and  314  serving as paper storage portions in the printer section  300 , and the manual paper feed portion  315  serving as a tray exposed outside the apparatus. 
   To register a paper type corresponding to the cassette  313 , the user clicks a paper feed portion  3  button  1801 . A window for setting the paper type of paper sheets in a paper feed portion corresponding to the cassette  313  is displayed in response to the click of the button  1801 . To register a paper type corresponding to the cassette  314 , the user clicks a paper feed portion  4  button  1802 . A window for setting the paper type of paper sheets in a paper feed portion corresponding to the cassette  314  is displayed in response to this operation. This also applies to the remaining paper feed portions. 
   Each button represents the paper size and paper type of paper sheets set in a corresponding paper feed portion. For example, paper sheets with a paper size “LTR” and a paper type “plain paper” are set in the cassette  311 . Paper sheets with a paper size “B5” and a paper type “plain paper” are set in the cassette  312 . Paper sheets with a paper size “A4” and a paper type “index sheet” are set in the cassette  313 . Paper sheets with a paper size “A4” and a paper type “index sheet” are set in the cassette  314 . 
   When a button  1803  for closing the current paper type registration window is clicked, the window of  FIG. 13  returns to a previous window, or, the common specification setting window. 
     FIG. 14  is a view showing a paper type registration window displayed on the liquid crystal screen of the operation section  150  in response to the click of the paper feed portion  3  button  1801  for registering a paper type corresponding to the cassette  313  in the paper type registration window shown in  FIG. 13 . This also applies to the remaining cassettes or trays. 
   The paper type registration window displays buttons corresponding to registerable paper types in order to register a paper type corresponding to the cassette  313 . Any one of plain paper ( 1901 ), recycled paper ( 1902 ), colored paper ( 1903 ), and an index sheet  1906  can be selected by clicking any button. The plain paper, recycled paper, and colored paper are recognized as plain paper for whether “to consider the paper type” in auto cassette change. That is, these paper sheets are determined as compatible ones in auto cassette change between these types. When the paper type consideration button  1715  shown in  FIG. 12  is ON, the control section  110  can change a paper feed portion which runs out of paper sheets (auto cassette change) even if the paper type changes such that plain paper changes to recycled paper or recycled paper changes to colored paper. 
   As special types of paper, paper types such as thick paper  1904 , intermediate print  1905 , and the index sheet  1906  can also be registered. For these special types of paper, a paper feed portion which runs out of paper sheets is not changed between different paper types. That is, auto paper feed portion change is not executed between different paper types, such as between thick paper and plain paper, recycled paper and intermediate print, or index sheet and thick paper. Auto paper feed portion change is done between paper sheets of the same type, for example, between thick paper and thick paper, intermediate print and intermediate print, and index sheet and index sheet. 
   In  FIG. 14 , the user registers the paper type of a paper feed portion selected in  FIG. 13  by selecting the buttons  1901  to  1906  representing paper types. To register the selected paper type (i.e., store it in the control section  110  for each paper feed portion), the user selects an OK button  1908 . To return to a previous window without any registration, the user selects a cancel button  1907 . 
   The index sheet takes various division numbers (index numbers) even for the same size. When the index sheet is selected, its division number is also set. 
     FIG. 15  is a view showing an index sheet setting window displayed on the liquid crystal screen of the operation section  150  in response to the click of the index sheet button  1906  in the paper type registration window shown in  FIG. 14 . 
   An index sheet has an index portion on a tab, and the index portion extends from a normal paper size to allow chaptering of a paper bundle. Several division numbers can be set for the index portion, and the division number can be set in the index number setting window for the index sheet in  FIG. 15 . In  FIG. 15 , the division number is 5, as displayed in a display window  2003 . This division number can be set from a minimum of 1 to a maximum of 10. A + button  2002  is selected to increase the division number, and a − button  2001  is selected to decrease the division number. The maximum value of the division number is not limited to this. When a button  2004  is clicked, designation of the division number (index number) ends, and the current window returns to the paper type registration window. 
   The means for setting whether to enable paper feed portion change for each paper feed portion according to the present invention, the means for setting a paper type for each paper feed portion, and the means for setting an index number when the paper type is an index sheet have been described with reference to  FIGS. 8 to 15 . 
   Parameters registered in the control section  110  by the above operations and the sensor of the image forming apparatus are as follows.
         (1) Setting of a paper feed portion subjected to auto cassette change for each job type   (2) Designation of whether to consider the paper type in auto cassette change for each job type   (3) Paper size for each paper feed portion   (4) Paper type for each paper feed portion   (5) Division number for each paper feed portion when the paper type is an index sheet       

   Other parameters can also be set and read by the sensor. In  FIG. 16  to be described later, these parameters are referred to. 
   &lt;Automatic Paper Feed Portion Change Sequence&gt; 
   The sequence of an automatic paper feed portion change function (auto cassette change function) by the image forming apparatus according to the embodiment will be explained with reference to  FIGS. 16A and 16B . 
   As shown in  FIG. 6 , the control section  110  and printer section  300  exchange paper feed/delivery control commands. As shown in  FIG. 6 , the control section  110  notifies the printer section  300  which paper feed portion is to feed a paper sheet when the control section  110  issues the printing execution request  9003  to the printer section  300 . This notification is sent by determining a paper feed portion for use by the control section  110  in accordance with a paper size and paper type designated by the operation panel  150  or a host computer, and notifying the printer section  300  of the determined paper feed portion. When no paper sheet exists in the notified paper feed portion, the printer section  300  notifies the control section  110  of the paper feed result status  9004  as a “no paper sheet” error.  FIGS. 16A and 16B  show a sequence performed by the control section  110  which has received the “no paper sheet” error. 
   In  FIGS. 16A and 16B , the control section  110  which has notified the printer engine of a given paper feed portion to try printing and has received the “no paper sheet” error from the printer engine executes the processing from step S 2102 . 
   In step S 2102 , the control section  110  determines whether the current paper feed portion which runs out of paper sheets is a paper feed portion subjected to auto cassette change (ACC) designated in the window of  FIG. 12 . This determination is done by referring to the parameter (1). If YES in step S 2102 , the flow advances to step S 2103 ; if NO, to step S 2115 . 
   For control of specifying a paper feed portion subjected to auto cassette change, the embodiment defines the priority order of paper feed portions, and paper feed portion selection processing is performed in accordance with the priority order. The criterion of determining the priority order is based on, e.g., a paper feed portion with a short convey path or a paper feed portion with a large paper feed capacity, but the present invention is not limited to this. In the embodiment, priorities are given to the cassettes  311 ,  312 ,  313 , and  314  and manual paper feed portion  315  serving as paper feed portions of the printer section  300  sequentially from a paper feed portion with a shorter convey path to the transfer portion  325 . The priority order of paper feed portions in the printer section  300  shown in  FIG. 2  is an order of the cassettes  311 ,  312 ,  313 , and  314  and manual paper feed portion  315 . 
   In step S 2103 , the control section  110  selects a paper feed portion having a higher priority among the paper feed portions on the basis of a predetermined priority order. 
   In step S 2104 , the control section  110  determines whether no other paper feed portion exists except a paper feed portion which runs out of paper sheets in selecting a paper feed portion in accordance with the priority order, or whether all paper feed portions have already been selected. If no other paper feed portion exists or all paper feed portions have already been selected, the flow advances to step S 2115 . If NO in step S 2104 , the flow advances to step S 2105 . 
   In step S 2105 , the control section  110  determines whether the selected paper feed portion is a paper feed portion subjected to auto cassette change (ACC) designated in  FIG. 12 . This determination is done on the basis of whether the paper feed portion of interest is set in the parameter (1). If YES in step S 2105 , the flow advances to step S 2106 ; if NO, the flow returns to step S 2103  to select a paper feed portion having the next priority. 
   In step S 2106 , the control section  110  determines whether paper sheets exist in the selected paper feed portion. If YES in step S 2106 , the flow advances to step S 2107 ; if NO, the flow returns to step S 2103  to select a paper feed portion having the next priority. 
   In step S 2107 , the control section  110  determines whether the size of paper sheets stored in the paper feed portion which runs out of paper sheets coincides with the size of paper sheets stored in the selected paper feed portion. If YES in step S 2107 , the flow advances to step S 2108 ; if NO, the flow returns to step S 2103  to select a paper feed portion having the next priority. 
   In step S 2108 , the control section  110  determines whether the paper type of the paper feed portion which runs out of paper sheets coincides with that of the selected paper feed portion. The paper type is the paper type of each paper feed portion that is registered in the paper type registration windows shown in  FIGS. 13 and 14 . If YES in step S 2108 , the flow advances to step S 2109 ; if NO, the flow advances to step S 2111 . 
   In step S 2109 , the control section  110  determines whether the paper type of the paper feed portion which runs out of paper sheets and that of the selected paper feed portion are an index sheet. If YES in step S 2109 , the flow advances to step S 2110 ; if NO, the flow advances to step S 2114 . 
   If the paper type is an index sheet, the control section  110  determines in step S 2110  whether the index number of the index sheet in the paper feed portion which runs out of paper sheets and that of the index sheet in the selected paper feed portion coincide with each other. The determined index number is based on registration of the index number shown in  FIG. 15 . If YES in step S 2110 , the flow advances to step S 2114 ; if NO, the flow returns to step S 2103  to select a paper feed portion having the next priority. 
   In step S 2111  to which the flow advances when the paper types are determined in step S 2108  not to coincide with each other, the control section  110  determines for the current job whether consideration of the paper type has been designated. Designation of considering the paper type is set by the “paper type consideration button  1715 ” shown in  FIG. 12 . If YES in step S 2111 , the flow advances to step S 2112 ; if NO, the flow returns to step S 2103  to select a paper feed portion having the next priority. 
   In step S 2112 , the control section  110  determines whether the paper type of the paper feed portion which runs out of paper sheets is a paper type selectable when paper types do not coincide with each other. The paper type selectable even when paper types do not coincide with each other includes plain paper, recycled paper, and colored paper described with reference to  FIG. 14 . If YES in step S 2112 , the flow advances to step S 2113 ; if NO, the flow returns to step S 2103  to select a paper feed portion having the next priority. 
   In step S 2113 , the control section  110  determines whether the paper type of the selected paper feed portion is a paper type selectable when paper types do not coincide with each other. The paper type selectable even when paper types do not coincide with each other includes plain paper, recycled paper, and colored paper described with reference to  FIG. 14 . If YES in step S 2113 , the flow advances to step S 2114 ; if NO, the flow returns to step S 2103 . 
   In step S 2114 , the control section  110  determines that paper feed operation can continue from the selected paper feed portion, and thus continues paper feed operation from the selected paper feed portion. The flow advances to step S 2116  and ends. 
   In step S 2115 , the control section  110  determines that paper feed operation cannot continue from a paper feed portion other than the paper feed portion which runs out of paper sheets. The control section  110  stops paper feed operation, displays a window representing the absence of paper sheets on the operation section  150 , and ends the flow. 
     FIG. 17  shows an example when no auto cassette change is executed by the above sequence for an index sheet.  FIG. 18  shows an example when auto cassette change is executed. 
   By the sequence shown in  FIGS. 16A and 16B , even an image forming apparatus having an auto cassette change function of changing a predetermined paper feed portion to another one and continuing printing when the predetermined paper feed portion runs out of paper sheets during printing (which includes not only printing operation in a printer, but also printing operation in an image forming apparatus having a printing function such as a copying apparatus or facsimile apparatus) does not execute automatic paper feed portion change if not only paper sizes but also index numbers do not coincide with each other for an index sheet. This can prevent output of a printed material not intended by the user. In other words, this can prevent selecting paper sheets with different index numbers such as an index sheet with an index number of 4 and an index sheet with an index number of 5, as identical paper sheets subjected to auto cassette change. 
   In the embodiment, a paper feed portion subjected to auto cassette change is designated in advance. The present invention is also effective in an image forming apparatus in which no paper feed portion subjected to auto cassette change can be designated but all cassettes or trays are subjected to auto cassette change. 
   In the embodiment, auto cassette change is executed when a paper feed portion runs out of paper sheets. The present invention is, however, not limited to this. 
   As described above, the present invention can shorten the operation stop time and increase the apparatus availability and printing processing productivity by successively using a plurality of paper feed portions. At the same time, when a plurality of paper feed portions store index sheets but their types do not coincide with each other, auto paper feed portion change processing is controlled not to be performed. This can prevent any output result not intended by the user. 
   First Modification to Embodiment 
   Index sheets are different not only in size and division number, but also in the shape of the index portion. Also in this case, auto cassette change is preferably inhibited. In  FIG. 15 , only the index division number is set. Further, other differences such as the shape of the index portion are set, which can increase the auto cassette change precision of index sheets. In this setting, the user can assign and register a type number or the like for causing the control section  110  to recognize, among others, the shape of the index sheet. In this case, the type number means an index representing that auto cassette change can be performed if type numbers coincide with each other. Instead of step S 2110  in  FIG. 16 , or when the determination result of step S 2110  is “YES”, the type numbers of index sheets set in a paper feed portion serving as the change source of auto cassette change and a (selected) paper feed portion serving as the change destination are compared with each other. When these type numbers coincide with each other, step S 2114  is executed; otherwise, the flow returns to step S 2103 . 
   With this processing, whether the numbers of index portions as well as shapes or the like coincide with each other, can be determined. If the types of index sheets do not coincide with each other, the auto cassette change function can be disabled. 
   Second Modification to Embodiment 
   In the embodiment, the user sets the paper type, index number, and the like. The present invention can, however, also be practiced when these parameters are detected by sensors and automatically set without any labor of the user. 
   Other Embodiments 
   Note that the present invention can be applied to an apparatus comprising a single device or to system constituted by a plurality of devices. 
   Furthermore, the invention can be implemented by supplying a software program (shown in  FIG. 16 ), which implements the functions of the foregoing embodiments, directly or indirectly to a system or apparatus, reading the supplied program code with a computer of the system or apparatus, and then executing the program code. In this case, so long as the system or apparatus has the functions of the program, the mode of implementation need not rely upon a program. 
   Accordingly, since the functions of the present invention are implemented by computer, the program code itself installed in the computer also implements the present invention. In other words, the claims of the present invention also cover a computer program for the purpose of implementing the functions of the present invention. 
   In this case, so long as the system or apparatus has the functions of the program, the program may be executed in any form, e.g., as object code, a program executed by an interpreter, or scrip data supplied to an operating system. 
   Example of storage media that can be used for supplying the program are a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a magnetic tape, a non-volatile type memory card, a ROM, and a DVD (DVD-ROM and a DVD-R). 
   As for the method of supplying the program, a client computer can be connected to a website on the Internet using a browser of the client computer, and the computer program of the present invention or an automatically-installable compressed file of the program can be downloaded to a recording medium such as a hard disk. Further, the program of the present invention can be supplied by dividing the program code constituting the program into a plurality of files and downloading the files from different websites. In other words, a WWW (World Wide Web) server that downloads, to multiple users, the program files that implement the functions of the present invention by computer is also covered by the claims of the present invention. 
   Further, it is also possible to encrypt and store the program of the present invention on a storage medium such as a CD-ROM, distribute the storage medium to users, allow users who meet certain requirements to download decryption key information from a website via the Internet, and allow these users to decrypt the encrypted program by using the key information, whereby the program is installed in the user computer. 
   Furthermore, besides the case where the aforesaid functions according to the embodiments are implemented by executing the read program by computer, an operating system or the like running on the computer may perform all or a part of the actual processing so that the functions of the foregoing embodiments can be implemented by this processing. 
   Furthermore, after the program read from the storage medium is written to a function expansion board inserted into the computer or to a memory provided in a function expansion unit connected to the computer, a CPU or the like mounted on the function expansion board or function expansion unit performs all or a part of the actual processing so that the functions of the foregoing embodiments can be implemented by this processing. 
   As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.