Patent Publication Number: US-2009232521-A1

Title: Image forming apparatus, method of controlling the image forming apparatus, and storage medium

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image forming apparatus, such as a copying machine provided with a sheet conveying mechanism including a plurality of component rollers, a method of controlling the image forming apparatus, and a storage medium storing a control program for implementing the method. 
     2. Description of the Related Art 
     Conventionally, maintenance of a copying machine or the like apparatus for business use has been carried out by a service person dispatched e.g. to an office where the apparatus is installed. 
     The maintenance work includes replacement of component rollers as consumables provided in the apparatus, and after the replacement of the component rollers, the service person checks whether or not each new component roller is normally operating. 
     The check is generally achieved by configuring settings for enabling a new component roller to operate in the apparatus and then actually operating the component roller. The service person is well informed about a mechanism of the copying machine or the like for operating a new component roller after replacement, so that he/she can configure appropriate settings according to the new component roller and its location, based on his/her technical knowledge (see Japanese Patent Laid-Open Publication No. 2007-072118). 
     Now, it is desired that even an image forming apparatus, such as a copying machine, for business use is configured such that replacement of a component roller can be easily performed by a user him/herself as well. 
     However, not all general users are well informed, as all service persons are, about the mechanism of a copying machine or the like apparatus for operating a new component roller after replacement, and hence some users have difficulty in configuring appropriate settings for checking the operation of the new component roller. 
     For example, in the case of replacing a plurality of component rollers constituting a sheet conveying path e.g. in a copying machine, it is difficult to judge the relationship between settings of sheet feeders, an inverting path, etc. and the operations of the component rollers, for checking determining the operations of the component rollers. 
     SUMMARY OF THE INVENTION 
     The present invention provides an image forming apparatus which enables even a user who is not well informed about the mechanism of the image forming apparatus to easily perform operation check on a component roller, a method of controlling the image forming apparatus, and a storage medium storing a control program for implementing the method. 
     In a first aspect of the present invention, there is provided an image forming apparatus provided with a sheet conveying mechanism including a plurality of component rollers, comprising a selecting unit configured to select a component roller to be subjected to operation check from the component rollers, a determining unit configured to determine a sheet conveying path passing the component roller selected by the selecting unit, and a control unit configured to control the sheet conveying mechanism such that a sheet is conveyed along the conveying path determined by the determining unit. 
     In a second aspect of the present invention, there is provided a method of controlling an image forming apparatus provided with a sheet conveying mechanism including a plurality of component rollers, comprising selecting a component roller to be subjected to operation check from the component rollers, determining a sheet conveying path to pass the selected component roller, and controlling the sheet conveying mechanism such that a sheet is conveyed along the determined conveying path. 
     In a third aspect of the present invention, there is provided a computer-readable storage medium storing a program for causing a computer to execute a method of controlling an image forming apparatus provided with a sheet conveying mechanism including a plurality of component rollers, wherein the method comprises selecting a component roller to be subjected to operation check from the component rollers, determining a sheet conveying path to pass the selected component roller, and controlling the sheet conveying mechanism such that a sheet is conveyed along the determined conveying path. 
     According to the present invention, a conveying path including a component roller targeted for operation check is automatically set. Therefore, it is possible for even a user who is not well informed about the mechanism of the image forming apparatus to easily perform the operation check on the component roller after replacement. 
     The features and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of the appearance of an image forming apparatus according to an embodiment of the present invention. 
         FIG. 2  is a schematic cross-sectional view of the image forming apparatus in  FIG. 1 . 
         FIG. 3  is a block diagram of a controller. 
         FIG. 4  is a schematic view of the appearance of an operating section. 
         FIG. 5  is a schematic view of a liquid crystal operation panel with a standby screen in a normal copy operation mode displayed thereon. 
         FIG. 6  is a schematic view of the liquid crystal operation panel with a component replacement status screen displayed thereon. 
         FIG. 7  is a schematic view of the liquid crystal operation panel with an operation check job configuration screen displayed thereon. 
         FIG. 8  is a diagram of an example of a configuration table for use in configuring settings for component roller operation check. 
         FIG. 9  is a view of an example of a screen displaying results of component roller operation check. 
         FIG. 10  is a schematic cross-sectional view of the image forming apparatus, in which a conveying path determined for execution of operation check on component rollers is indicated by a dotted line. 
         FIG. 11  is a flowchart of an operation check process executed by the image forming apparatus according to the present embodiment. 
         FIG. 12  is a schematic cross-sectional view of the image forming apparatus, in which a conveying path determined for execution of operation check on different component rollers from the component rollers targeted in  FIG. 10  is indicated by a dotted line. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The present invention will now be described in detail below with reference to the accompanying drawings showing embodiments thereof. 
       FIG. 1  is a view of the appearance of an image forming apparatus according to the embodiment of the present invention.  FIG. 2  is a schematic cross-sectional view of the image forming apparatus in  FIG. 1 . 
     As shown in  FIGS. 1 and 2 , the image forming apparatus according to the present embodiment is comprised of a scanner section  10  and a printer section  20 . 
     In the scanner section  10 , when a user operates an operating section  140  to give an instruction for starting reading of images from originals, the originals fed from an automatic original feeder  142  by a sheet feed roller  950  are sequentially brought onto an original platen glass  901 . 
     An original placed on the original platen glass  901  is irradiated with illuminating light emitted from an original illuminating lamp  902  implemented e.g. by a halogen lamp, and reflected light from the irradiated original is guided to an image pickup element unit  906  via scanning mirrors  903 ,  904 , and  905  reciprocating in the sub scanning direction. 
     The image pickup element unit  906  is comprised of an image pickup element  908  implemented e.g. by a CCD, an imaging lens  907  through which the reflected light from the original is formed on the image pickup element  908 , and a driver  909  for driving the image pickup element  908 . 
     An image output signal from the image pickup element  908  is converted into e.g. 8-bit digital data, and then input to a controller  30 . The controller  30  includes a microcomputer and an image processing section, and performs an image forming operation, described hereinafter, according to an instruction from a man machine interface device  940 . 
     In the printer section  20 , residual charge remaining on a photosensitive drum  910  is removed by a pre-exposure lamp  912  for an image forming operation, whereafter the surface of the photosensitive drum  910  is uniformly charged by a primary electrostatic charger  913 . In this state, the photosensitive drum  910  is irradiated for exposure with a semiconductor laser beam from an exposure unit  917  based on image data processed by the controller  30 , whereby an electrostatic latent image is formed on the surface of the photosensitive drum  910 . 
     The electrostatic latent image is developed into a toner image by a development device  918 . A high voltage is applied to the toner image developed on the photosensitive drum  910  by a pre-transfer charger  919  before the toner image is transferred onto a sheet. 
     On the other hand, a sheet fed from one of a manual feed tray  920  and sheet feeders  922 ,  924 ,  942 , and  944  is conveyed into a conveying path by driving associated one of a conveying roller  921 , and sheet feed rollers  923 ,  925 ,  943 , and  945 . 
     The sheet conveyed into the conveying path is once stopped at a registration roller  926 , and is then conveyed through between the photosensitive drum  910  and a transfer charger  927  in timing synchronous with transfer of the toner image formed on the photosensitive drum  910 . 
     Thus, the toner image formed on the photosensitive drum  910  is transferred onto the sheet, and the sheet having the toner image transferred thereon is separated from the photosensitive drum  910  by a separation charger  928 . Further, residual toner remaining on the surface of the photosensitive drum  910  without being transferred onto the sheet is collected by a cleaner  911 . 
     The sheet separated from the photosensitive drum  910  is conveyed to a fixing device  930  by a conveying belt  929 , and the unfixed toner image on the sheet is fixed e.g. by heat. The sheet having passed through the fixing device  930  is selectively guided into a conveying passage to a discharge roller pair  941  or a conveying passage to an intermediate tray  937  by a switching operation of a flapper  931 . 
     When the conveying passage to the intermediate tray  937  is selected, conveying roller pairs  933  to  936  convey the sheet to the intermediate tray  937  after inverting the same (for a multiple overlay printing) or without inverting the same (for double-sided printing). The sheet having conveyed to the intermediate tray  937  is conveyed to the registration roller  926  again by a refeed roller  938 , and an image forming operation is perform in the same way as described above. 
     Next, the controller  30  will be described with reference to  FIG. 3 . 
     The controller  30  is connected to the scanner section  10  and the printer section  20 , and includes a CPU  1201  for controlling the overall operation of the apparatus. 
     The CPU  1201  loads a control program stored in an HDD  1204  into a RAM  1202 , and executes predetermined processes. The RAM  1202  is a system work memory used by the CPU  1202  for operation. The RAM  202  also temporarily stores image data. A ROM  1203  stores a system boot program. The HDD  1204  stores system software, application software, image data, and so forth. 
     An operating section interface  1206  provides interface with the operating section (UI: User Interface)  140 , and outputs to the operating section  140  image data to be displayed on the same. The operating section interface  1206  also outputs information input by the user via the operating section  140  to the CPU  1201 . 
     A network interface  1210  is connected to a LAN  3300 , for input and output of various kinds of data concerning outputting images and information concerning apparatus control. Further, the network interface  1210  receives outputting image data from a host computer  1100  and an outputting image data management apparatus, not shown, on the network according to a user input operation performed via the operating section  140 , and performs image output. 
     A modem  1250  is connected to a public communication line (WAN)  1251 , for input and output of information. A voice input and output unit  500  performs control for outputting voice to a speaker, and outputting and inputting voice to a handset. 
     A wireless LAN  1270  is connected to peripheral apparatuses  1253 , such as a digital camera and a PC, connected by a radio  1252 , for input and output of various kinds of data concerning outputting images and information concerning apparatus control. 
     A scanner/printer communication interface  1208  provides interface for communication with a CPU, not shown, of each of the scanner section  10  and the printer section  20 . Further, instructions for sheet conveyance control, which characterizes the present invention, for operation check on various kinds of rollers are issued via the scanner/printer communication interface  1208 . 
     A timer  1211  functions to perform time setting for the image forming apparatus and the controller  30  and generate an interrupt at predetermined time intervals. The above-mentioned devices are arranged on a system bus  1207 , and the system bus  1207  and an image bus  2008  for high-speed transfer of image data are interconnected by an image bus interface  1205  as a bus bridge for converting data structures. 
     The image bus  2008  is implemented by a PCI bus, an IEEE 1394 bus or the like. On the image bus  2008 , there are arranged a RIP  1260 , a device interface  1220 , a scanner image processing section  1280 , a printer image processing section  1290 , an image rotation section  1230 , and an image compressor  1240 . 
     The RIP (Raster Image Processor)  1260  expands a PDL code into a bitmap image. The device interface  1220  connects the controller  30  to the scanner section  10 , the printer section  20 , etc. to perform synchronous-to-asynchronous or asynchronous-to-synchronous conversion of image data. 
     The scanner image processing section  1280  corrects, processes, and edits input image data. The printer image processing section  1290  performs correction, resolution conversion, etc. of image data to be printed out by the printer  20 . 
     The image rotation section  1230  rotates image data. The image compressor  1240  compresses or expands multi-valued image data by JPEG, and binary image data by JBIG, MMR or MH. 
     Next, the operating section  140  will be described with reference to  FIG. 4 . 
     As shown in  FIG. 4 , on the operating section  140 , there are arranged a liquid crystal operation panel  2301 , a start key  2302 , a stop key  2303 , ten keys  2306 , a clear key  2305 , a reset key  2304 , and so forth. 
     The liquid crystal operation panel  2301  is formed e.g. by a combination of a liquid crystal panel and a touch panel. On the liquid crystal operation panel  2301  are displayed settings, soft keys, etc. The start key  2302  is a hard key used to give an instruction for starting a copy operation or the like. The start key  2302  incorporates green and red LEDs, and the green LED illuminates to indicate that it is possible to start, and the red LED illuminates to indicate that it is impossible to start. 
     The stop key  2303  is a hard key used to stop an operation. The ten keys  2306 , the clear key  2305 , and the reset key  2304  are also provided as a hard key group. 
       FIG. 5  shows the liquid crystal operation panel  2301  with a standby screen in a normal copy operation mode being displayed thereon. The standby screen shown in  FIG. 5  is a standard screen displayed in a case where no rollers to be replaced are detected when the power of the image forming apparatus is turned on. 
     On the standby screen are arranged operating mode selection keys, i.e. a COPY key  2420 , a SEND key  2421 , a BOX key  2422 , and a SCAN key  2423 . When one of the operating mode selection keys is pressed, the standby screen is switched to a screen for a mode associated with the pressed key. 
     Further, on the standby screen are arranged a setting display section  2411 , a zoom soft key group  2412 , a sorter key  2414 , a double-sided printing key  2415 , a sheet selection key  2416 , a density designation key group  2417 , an application mode key  2418 , and a character/photograph key  2419 . 
     In the setting display section  2411  are displayed a current operation status of the image forming apparatus, a magnification, a sheet type, and the number of copies, which are currently set. The zoom soft key group  2412  is comprised of a 100% magnification key, an enlargement key, a reduction key, and a zoom key as soft keys concerning the magnification in copying. 
     The 100% magnification key is pressed to set the copy magnification to 100%. The reduction key and the enlargement key are pressed to perform fixed-ratio reduction and enlargement, respectively. The zoom key is pressed to perform unfixed-ratio reduction and enlargement in steps of 1%. 
     The sorter key  2414  is used to designate a method of processing printed sheets The double-sided printing key  2415  is used to designate double-sided printing for an original or an output method. The sheet selection key  2416  is used to perform transition to a screen for designating the size, color, material, etc. of printing sheets. In the present embodiment, sheet feed control is performed based on sheets selected using the sheet selection key  2416 . 
     The density designation key group  2417  is used to adjust the density of a read image or a printed image. The application mode key  2418  is used to perform transition to an application mode screen. 
       FIG. 6  shows the liquid crystal operation panel  2301  with a component replacement status screen  3001  displayed thereon. The component replacement status screen  3001  is displayed on the liquid crystal operation panel  2301  when roller replacement is detected upon power-on of the image forming apparatus. 
     On the component replacement status screen  3001  are arranged detected roller display boxes  3003  for displaying a list of rollers of which replacement has been detected, status display boxes  3002  each indicating whether or not operation check is required, and check boxes  3004  for selecting rollers to be subjected to operation check. 
     Further, on the component replacement status screen  3001  are arranged an operation check button  3005  used to give an instruction for execution of operation check and display an operation check job configuration screen, and a cancel button  3006  used to switch to a normal operation. 
     For selection of a component roller to be subjected to operation check, such a cross section of the apparatus as shown in  FIG. 2  may be displayed on the component replacement status screen  3001  in  FIG. 6  in place of the list of rollers of which replacement has been detected. 
       FIG. 7  shows the liquid crystal operation panel  2301  with an operation check job configuration screen  4001  displayed thereon. 
     The operation check job configuration screen  4001  is displayed when a roller whose operation is to be checked is selected by entering a check mark in an associated check box  3004  on the component replacement status screen  3001  and then the operation check button  3005  is pressed, for determining a conveying path including the selected roller. 
     On the operation check job configuration screen  4001 , there are arranged a sheet feeder-setting display box  4002 , a single-sided/double-sided printing-setting display box  4003 , a discharger-setting display box  4004 , and a printing sheet count display box  4005 . Further, there is disposed an OK button  4006  used for giving an instruction for executing operation check based on settings configured using the boxes  4002 ,  4003 ,  4004 , and  4005 . 
       FIG. 8  shows an example of a configuration table for use in configuring settings for component roller operation check. 
     This configuration table determines in advance the relationship between each of the component rollers and a conveying path associated therewith. The configuration table is recorded and stored in a storage unit, such as the RAM  1202 . 
     In the  FIG. 8  example, boxes associated with component rollers selected for operation check by entering check marks in the respective checkboxes  3004  associated therewith in the  FIG. 6  component replacement status screen  3001  are shown in a shaded manner. 
     For example, for a sheet feed roller  3 , “sheet feeder  3 ” is designated by sheet feeder-setting, “single-sided” by single-sided/double-sided printing-setting, and “discharge tray  1 ” by discharger setting. 
     As described above, in executing operation check by conveying a sheet such that it passes each component roller selected in the component replacement status screen  3001 , settings for operating the component roller are recorded and stored in the RAM  1202  in a tabulated form. 
     This table is shown only by way of example, and component rollers and settings associated therewith are by no means limited to examples shown in  FIG. 8 . 
       FIG. 9  shows an example of a screen displaying results of component roller operation check. 
     On an operation check result display screen  5001 , which corresponds to the component replacement status screen  3001  in  FIG. 6 , the result of operation check performed on each of the selected component rollers is displayed as “OK” or “NG” in an associated operation check box  5002  (corresponding to the status display box  3002  in  FIG. 6 ). 
     Further, on the operation check result display screen  5001 , there are arranged an OK button  5004  used to show recognition of the results of operation check and terminate the check operation, and a re-check button  5003  used to give an instruction for executing re-check when “NG” is displayed in any operation check box  5002 . 
       FIG. 10  is a schematic cross-sectional view of the image forming apparatus, in which a conveying path  990  determined for execution of a component roller check operation is indicated by a dotted line. 
     In  FIG. 10 , components corresponding to the component rollers selected for operation check using the associated checkboxes  3004  on the component replacement status screen  3001  in  FIG. 6  are displayed in a shaded manner, and the conveying path  990  is configured such that a sheet passes these component rollers. 
     The cross-sectional view of the image forming apparatus in which the conveying path  990  is shown as described above may be displayed on the liquid crystal operation panel  2301  in place of the operation check job configuration screen  4001  in  FIG. 7 . 
       FIG. 12  is a schematic cross-sectional view of the image forming apparatus, in which a conveying path  991  determined so as to perform a check operation on different component rollers from the shaded ones in  FIG. 10  is indicated by a dotted line. 
     In the present example, “conveying roller  1 ” and “discharge roller pair” are designated as targeted component rollers for operation check. In  FIGS. 10 and 12 , components are displayed by further adding reference numerals to related component names for ease of understanding of the description of the present embodiment. 
     Next, an operation check process executed by the image forming apparatus of the present embodiment will be described with reference to  FIG. 11 . In the operation check process of the present embodiment, a conveying path to pass the component rollers to be subjected to operation check is automatically set. The operation check process in  FIG. 11  is executed by the CPU  1201  based on the control program loaded into the RAM  1202  from a storage unit (i.e. the ROM  1203  or the HDD  1204 ). 
     First, in a step S 1001 , the CPU  1201  determines whether or not there is a component roller requiring operation check. In the present embodiment, the determination is performed based on a signal (detection result) from a replacement detecting unit, not shown, for detecting component roller replacement. 
     Alternatively or additionally, the user may designate a component roller requiring operation check via the operating section  140  to cause the CPU  1201  to determine, based on the input information, that the component roller requires operation check. 
     If the CPU  1201  determines that there is a component roller requiring operation check, the process proceeds to a step S 1002 , whereas if not, the process proceeds to a step S 1011 , wherein a normal image forming operation is carried out. 
     In the step S 1002 , based on the determination in the step S 1001  that there is a component roller requiring operation check, the CPU  1201  controls the operating section interface  1206  to display the component replacement status screen  3001  (see  FIG. 6 ) on the liquid crystal operation panel  2301 . On the component replacement status screen  3001  are displayed a list of component rollers requiring operation check, and the above-mentioned elements, etc. as described above. 
     Next, in a step S 1003 , the CPU  1201  accepts selection of component rollers requiring operation check from the list displayed on the component replacement status screen  3001 . The selection of the component rollers is performed by the user who checks ones to be selected of the checkboxes  3004  provided on the component replacement status screen  3001 . 
     Then, in a step S 1004 , the CPU  1201  determines whether or not the operation check button  3005  on the component replacement status screen  3001  has been pressed. If the operation check button  3005  has been pressed, the CPU  1201  judges that component rollers requiring operation check have been designated, and the process proceeds to a step S 1005 . 
     In the step S 1005 , the CPU  1201  reads out settings associated with the component rollers which are determined in the step S 1004 , by referring to information in the configuration table shown in  FIG. 8 , and determines a conveying path based on the read-out settings. Then, the process proceeds to a step S 1006 . 
     In the step S 1006 , the CPU  1201  controls the operating section interface  1206  to display the operation check job configuration screen  4001  shown in  FIG. 7  on the liquid crystal operation panel  2301 , and then the process proceeds to a step S 1007 . 
     In the step S 1007 , the CPU  1201  determines whether or not the OK button  4006  on the operation check job configuration screen  4001  has been pressed. If the OK button  4006  has been pressed, the process proceeds to a step S 1008 . 
     In the step S 1008 , the CPU  1201  controls a conveyance mechanism including the component rollers such that sheet feed, conveyance, and discharge are performed along the conveying path determined based on the operation check job settings determined in the step S 1005 . 
     At this time, the CPU  1201  detects sheet conveyance status, such as conveying timing and the number of times of retrial, via various sensors, not shown, arranged on the conveying path. Then, the CPU  1201  performs comparison between the results of the detection and associated threshold values to determine whether or not sheet conveyance has been normally performed. By doing this, the CPU  1201  checks the operations of the component rollers. 
     Next, in a step S 1009 , the CPU  1201  controls the operating section interface  1206  to display the operation check result display screen  5001  (see  FIG. 9 ) showing the operation check results obtained in the step S 1008  in association with the respective component rollers, on the liquid crystal operation panel (display section)  2301 . 
     When the operation of a component roller is normal, “OK” is displayed in an associated one of the operation check fields  5002  on the operation check result display screen  5001 , whereas when the operation of a component roller is not normal, “NG” is displayed in an associated one of the operation check fields  5002 . Further, when the operation check results obtained in the step S 1008  include at least one displayed as “NG”, i.e. when the operation of at least one component roller is not normal, the CPU  1201  controls the operating section interface  1206  to display the re-check button  5003  on the operation check result display screen  5001 . 
     Then, in a step S 1010 , the CPU  1201  determines whether or not the OK button  5004  on the operation check result display screen  5001  has been pressed. If the OK button  5004  has been pressed, the process is terminated, whereas if not, the process proceeds to a step S 1012 . 
     In the step S 1012 , the CPU  1201  determines whether or not the re-check button  5003  has been pressed. If the re-check button  5003  has been pressed, the process proceeds to a step S 1013 . 
     In the step S 1013 , the CPU  1201  executes component roller operation check again under the same conditions as the settings configured for operation check in the step S 1008 , and then the process proceeds to a step S 1014 . 
     In the step S 1014 , the CPU  1201  determines whether or not the number of times of depression of the re-check button  5003  has reached a predetermined number. If the number of times of depression of the re-check button  5003  has not reached the predetermined number, the process proceeds to a step S 1015 , whereas if the number of times of depression of the re-check button  5003  has reached the predetermined number, the process proceeds to a step S 1017 . 
     In the step S 1017 , the CPU  1201  determines whether or not operation check results obtained in the step S 1013  include at least one displayed as “NG”, i.e. whether or not the operation of at least one component roller is not normal. If the operation of at least one component roller is not normal, the process proceeds to a step S 1018 , whereas if the operations of all the component rollers are normal, the process proceeds to the step S 1015 . 
     In the step S 1018 , the CPU  1201  controls the operating section interface  1206  to display service call instructions e.g. on the liquid crystal operation panel  2301 . 
     In the step S 1015 , the CPU  1201  controls the operating section interface  1206  to display the operation check result display screen  5001  (see  FIG. 9 ) showing the operation check results obtained in the step S 1013  on the liquid crystal operation panel  2301  similarly to the step S 1009 . 
     Further, when the operation check results obtained in the step S 1013  include at least one displayed as “NG”, i.e. when the operation of at least one component roller is not normal, the CPU  1201  controls the operating section interface  1206  to display the re-check button  5003  on the operation check result display screen  5001 . 
     Then, in a step S 1016 , the CPU  1201  determines whether or not the OK button  5004  on the operation check result display screen  5001  has been pressed. If the OK button  5004  has been pressed, the operation check process is terminated. 
     On the other hand, if the OK button  5004  has not been pressed on the operation check result display screen  5001 , the process returns to the step S 1012 , and the same processing as described above is repeatedly carried out. 
     In the image forming apparatus of the present embodiment, when a plurality of component rollers targeted for operation check exist, it is sometimes impossible to perform operation check on all the component rollers via a single conveying path. 
     In this case, a plurality of conveying paths are set such that the number of sheets to be fed is minimized so as to suppress consumption of sheets. 
     For example, if all the component rollers described with reference to  FIGS. 10 and 12  are simultaneously targeted for operation check, it is impossible to perform operation check on all the component rollers only by feeding a single sheet. 
     For this reason, when these component rollers are all simultaneously targeted for operation check, operation check is performed twice by dividing sheet feed operation into two such that one sheet is fed from the sheet feeder  3 ( 942 ) and one sheet from the manual feed tray  920 . Therefore, in this case, a total of two sheets is the minimum number of sheets to be fed. 
     For another example, in the conveying path  990  shown in  FIG. 10 , a conveying roller pair  4  and the discharge roller pair have been replaced with new ones, respectively. 
     In this case, a conveying path passing the discharge roller pair and a conveying path passing the conveying roller pair  4  are configured not as two independent paths, but as a single path. In other words, a conveying path is determined such that component roller operation check can be performed by feeding only one sheet. 
     As described above, according to the present embodiment, a conveying path to pass component rollers targeted for operation check is automatically configured, which enables the user to easily check the operation of each component roller even if the user is not well informed about the mechanism of the image forming apparatus. This makes it easy for the user to replace component rollers by him/herself. 
     It should be noted that the present invention is not limited to the above-described embodiment, but it can be practiced in various forms, without departing from the spirit and scope thereof. 
     For example, although in the above described embodiment, the present invention is applied to an electrophotographic image forming apparatus using a photosensitive drum and the like, the present invention may be applied to an inkjet image forming apparatus which directly prints an image on a sheet by jetting ink onto the sheet from an array of small nozzles. 
     Further, it is to be understood that the present invention may also be accomplished by supplying a system or an apparatus with a storage medium in which a program code of software, which realizes the functions of the above described embodiment, is stored, and causing a computer (or CPU or MPU) of the system or apparatus to read out and execute the program code stored in the storage medium. 
     In this case, the program code itself read from the storage medium realizes the functions of the above described embodiment, and therefore the program code and the storage medium in which the program code is stored constitute the present invention. 
     Examples of the storage medium for supplying the program code include a floppy (registered trademark) disk, a hard disk, a magnetic-optical disk, an optical disk, such as a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, a DVD-RW, or a DVD+RW, a magnetic tape, a nonvolatile memory card, and a ROM. Alternatively, the program may be downloaded via a network. 
     Further, it is to be understood that the functions of the above described embodiment may be accomplished not only by executing the program code read out by a computer, but also by causing an OS (operating system) or the like which operates on the computer to perform a part or all of the actual operations based on instructions of the program code. 
     Further, it is to be understood that the functions of the above described embodiment may be accomplished by writing a program code read out from the storage medium into a memory provided on an expansion board inserted into a computer or a memory provided in an expansion unit connected to the computer and then causing a CPU or the like provided in the expansion board or the expansion unit to perform a part or all of the actual operations based on instructions of the program code. 
     While the present invention has been described with reference to an exemplary embodiment, it is to be understood that the invention is not limited to the disclosed exemplary embodiment. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures and functions. 
     This application claims priority from Japanese Patent Application No. 2008-067881 filed Mar. 17, 2008, which is hereby incorporated by reference herein in its entirety.