Abstract:
There is provided an image forming apparatus including a digital printing device that prints an image according to image signals and a digital scanning device, connectable to the digital printing device, that scans an image and converts the image into electric signals. The digital printing device includes a first nonvolatile memory for storing first parameters that optimize performance of the digital printing device. The digital scanning device includes a second nonvolatile memory for storing second parameters that optimize performance of the digital scanning device. The digital printing device includes a section for modifying the second parameters when the digital scanning device is connected to the digital printing device.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an image forming apparatus, such as a printer, a copier, a fax machine.  
           [0003]    2. Description of the Related Art  
           [0004]    A digital duplicating machine may have functions of a digital scanner and a digital printer, and a digital duplicating machine may even be formed by including both a digital scanner portion and digital printer portion. Digital scanners and digital printers have their own characteristic parameters, with which they are set to work at the best performance. For example, in a digital duplicating machine including a digital scanner portion and digital printer portion, the characteristic parameters of the digital scanner and digital printer are determined when they are fabricated in the factory and are usually stored in a non-volatile memory installed in the digital printer which usually works under sequential control.  
           [0005]    Even when a digital scanner and a digital printer are fabricated separately, furthermore, even after the digital scanner and the digital printer are shipped, for example, when they are in distribution, it is still possible to realize a digital duplicating machine by just connecting the digital scanner to the digital printer. In, this case, because the digital scanner and the digital printer are fabricated separately, the characteristic parameters of the digital scanner and the digital printer are originally stored in their own non-volatile memories. In this case, because generally the digital scanner and the digital printer include built-in micro-computers to control their respective operations, the micro-computers may communicate with each other to realize the function of a duplicating machine.  
           [0006]    However, when a digital scanner and a digital printer fabricated separately are connected later, the characteristic parameters of the digital scanner have to be modified to fit the overall performance of the digital duplicating machine. In this case, there arises a problem of management of the characteristic parameters, and this problem may make it difficult to realize the function of a digital duplicating machine.  
         SUMMARY OF THE INVENTION  
         [0007]    Accordingly, it is a general object of the present invention to solve the above problem of the related art.  
           [0008]    A first specific object of the present invention is to provide an image recording apparatus able to realize a function of a digital duplicating machine by connecting a digital scanning device to a digital printing device even when the digital scanning device and the digital printing device are in distribution.  
           [0009]    A second specific object of the present invention is to provide an image recording apparatus able to ensure the performance of a digital scanning device and manage characteristic parameters of the digital scanning device from a digital printing device.  
           [0010]    A third specific object of the present invention is to provide an image recording apparatus able to ensure the performance of a digital scanning device, manage characteristic parameters of the digital scanning device from a digital printing device, and maintain compatibility even when a different digital scanning device is connected to the digital printing device.  
           [0011]    A fourth specific object of the present invention is to provide an image recording apparatus able to ensure the performance of a digital scanning device, and maintain compatibility even when the digital scanning device is newly connected or the digital scanning device is connected to a different digital printing device.  
           [0012]    A fifth specific object of the present invention is to provide an image recording apparatus able to ensure the performance of a digital scanning device and eliminate the necessity of adjusting characteristic parameters of the digital scanning device even when the digital scanning device is newly connected.  
           [0013]    To attain the above objects, according to a first aspect of the present invention, there is provided an image forming apparatus, comprising a digital printing device that prints an image according to image signals input thereto, the digital printing device including a first nonvolatile memory for storing first parameters that optimize performance thereof, and a digital scanning device, connectable to the digital printing device, that scans an image and converts the image into electric signals, the digital scanning device including a second nonvolatile memory for storing second parameters that optimize performance thereof, wherein the digital printing device includes control means for modifying the second parameters when the digital scanning device is connected to the digital printing device.  
           [0014]    Preferably, the control means comprise reading means for reading the second parameters stored in the second nonvolatile memory of the digital scanning device when the digital scanning device is connected to the digital printing device, modification means for modifying the second parameters read by the reading means, and writing means for writing the modified second parameters to the second nonvolatile memory of the digital scanning device when the digital scanning device is connected to the digital printing device.  
           [0015]    Preferably, the control means comprise reading means for reading the second parameters stored in the second nonvolatile memory of the digital scanning device when the digital scanning device is connected to the digital printing device, modification means for modifying the second parameters read by the reading means, and writing means for writing the modified second parameters to the first nonvolatile memory of the digital printing device and the second nonvolatile memory of the digital scanning device when the digital scanning device is connected to the digital printing device.  
           [0016]    Preferably, the control means comprise reading means for reading the second parameters stored in the second nonvolatile memory of the digital scanning device when the digital scanning device is connected to the digital printing device, modification means for modifying the second parameters read by the reading means, and writing means for writing values equal to the modifications made by the modification means to the second nonvolatile memory of the digital scanning device when the digital scanning device is connected to the digital printing device.  
           [0017]    Preferably, the control means comprise reading means for reading the second parameters stored in the second nonvolatile memory of the digital scanning device when the digital scanning device is connected to the digital printing device, modification means for modifying the second parameters read by the reading means, and writing means for writing values equal to the modifications made by the modification means to the first nonvolatile memory of the digital printing device and the second nonvolatile memory of the digital scanning device when the digital scanning device is connected to the digital printing device.  
           [0018]    To attain the above objects, according to a second aspect of the present invention, there is provided a digital printing device that prints an image according to image signals input thereto, the digital printing device forming an image forming apparatus when connected with a digital scanning device that scans the image and converts the image into the image signals, the digital printing device including a first nonvolatile memory for storing first parameters that optimize performance thereof, and the digital scanning device including a second nonvolatile memory for storing second parameters that optimize performance thereof, the digital printing device comprising control means for modifying the second parameters when the digital scanning device is connected to the digital printing device.  
           [0019]    These and other objects, features, and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments given with reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a block diagram showing a hardware configuration of an image forming apparatus according to a first embodiment of the present invention;  
         [0021]    [0021]FIGS. 2A and 2B are views of memory maps of the EEPROM  18  and NVRAM  25  of the image forming apparatus according to the first embodiment of the present invention;  
         [0022]    [0022]FIG. 3 is a flow chart showing an example of the operation of the image forming apparatus according to the first embodiment of the present invention;  
         [0023]    [0023]FIGS. 4A and 4B are views of memory maps of the EEPROM  18  and NVRAM  25  of an image forming apparatus according to a second embodiment of the present invention;  
         [0024]    [0024]FIG. 5 is a flow chart showing an example of the operation of the image forming apparatus according to the second embodiment of the present invention;  
         [0025]    [0025]FIG. 6 is a flow chart showing another example of the operation of the image forming apparatus according to the second embodiment of the present invention;  
         [0026]    [0026]FIG. 7 is a flow chart showing an example of the operation of an image forming apparatus according to a third embodiment of the present invention;  
         [0027]    [0027]FIGS. 8A and 8B are views of memory maps of the EEPROM  18  and NVRAM  25  of an image forming apparatus according to a fourth embodiment of the present invention;  
         [0028]    [0028]FIG. 9 is a flow chart showing an example of the operation of the image forming apparatus according to the fourth embodiment of the present invention;  
         [0029]    [0029]FIGS. 10A and 10B are views of memory maps of the EEPROM  18  and NVRAM  25  of an image forming apparatus according to a fifth embodiment of the present invention;  
         [0030]    [0030]FIG. 11 is a flow chart showing an example of the operation of the image forming apparatus according to the fifth embodiment of the present invention;  
         [0031]    [0031]FIGS. 12A and 12B are views of memory maps of the EEPROM  18  and NVRAM  25  of an image forming apparatus according to a sixth embodiment of the present invention; and  
         [0032]    [0032]FIG. 13 is a flow chart showing an example of the operation of the image forming apparatus according to the sixth embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]    Below, preferred embodiments of the present invention are explained with reference to the accompanying drawings.  
         [0034]    In the following descriptions, as an example, the nonvolatile storage medium may be an NVRAM (NonVolatile Random Access Memory), which includes a power supply, or an EEPROM (Electrically Erasable Programmable Read-Only Memory), or an OTPROM (One Time Programmable Read-Only Memory), or a PROM (Programmable Read-Only Memory).  
         [0035]    First Embodiment  
         [0036]    [0036]FIG. 1 is a block diagram showing a hardware configuration of an image forming apparatus according to a first embodiment of the present invention.  
         [0037]    The image forming apparatus according to the first embodiment of the present invention includes a digital scanner  1  and a digital printer  2  connected to each other, thus having the function of a digital duplicating machine. The digital scanner  1  has an EEPROM  18 , and the digital printer  2  has an NVRAM  25 , which are nonvolatile memories.  
         [0038]    In the digital scanner  1 , a manuscript is placed on a glass window and is irradiated by a lamp  16 ; when a carriage holding the lamp  16  and an optical system moves, the manuscript is scanned in the sub scan direction; the light reflected from the manuscript or the light transmitted through the manuscript passes through the optical system, and is detected by a CCD  12  that acts as an image sensor; the light detected by the CCD  12  is converted into electrical signals in the CCD  12 , and from the image signals, the image on the manuscript is obtained by the digital scanner  1 . The image signals are amplified, combined, and are converted into digital signals (A/D conversion) in a signal processing unit  13 , and then are output to an image processing unit  26  of the digital printer  2 .  
         [0039]    The controller  11 , which comprises an IC chip, controls all parts of the digital scanner  1 ; specifically, the controller  11  switches ON or OFF an inverter  15  that drives the lamp  16 , drives a motor  17  to move the carriage mentioned above, accepts detection signals from a sensor  14  that detects the movement of the carriage, and accesses the EEPROM  18 .  
         [0040]    In the digital printer  2 , the main control section  21  has a CPU  22  that controls a not-illustrated engine of the digital printer  2  and the controller  11  of the digital scanner  1 . The CPU  22  operates according to the program stored in a ROM  23 ; it controls the digital printer  2  to work as a printer when the digital scanner  1  is not connected to the digital printer  2 , and when the digital scanner  1  is connected to the digital printer  2 , it controls all the components in the digital printer  2  and the digital scanner  1  so that the digital printer  2  and the digital scanner  1  together work as a digital duplicating machine.  
         [0041]    The RAM  24  temporarily stores data generated when the CPU  22  is in operation, and the NVRAM  25  stores characteristic parameters of the digital printer  2 . The characteristic parameters of the digital scanner  1  are stored in the EEPROM  18  connected to the controller  11 . Those parameters are written to the digital scanner  1  and the digital printer  2 , respectively, when they are fabricated in the factory. The image processing unit  26  receives and processes the image signals from the signal processing unit  13 , and outputs the image signals to the engine of the digital printer  2 . The engine of the digital printer  2  records an image on a medium, such as paper, according to the image signals from the image processing unit  26 .  
         [0042]    [0042]FIGS. 2A and 2B are views of memory maps of the EEPROM  18  and NVRAM  25 , respectively, of the image forming apparatus according to the first embodiment of the present invention.  
         [0043]    As illustrated in FIG. 2A, in the EEPROM  18 , for example, a header  31  is allocated in a region of a few bytes located from the address 0000H, and a data region  32  is allocated next to the header  31  to store the characteristic parameters of the digital scanner  1 .  
         [0044]    Similarly, as illustrated in FIG. 2B, in the NVRAM  25 , for example, a header  41  is allocated in a region of a few bytes located from the address 0000H, and a data region  43  is allocated next to the header  41  to store the characteristic parameters of the digital printer  2 .  
         [0045]    When the digital scanner  1  is fabricated, the characteristic parameters of the digital scanner  1  are stored in the data region  32 , and the initial values of the characteristic parameters are stored in the header  31  of the EEPROM  18 .  
         [0046]    Similarly, when the digital printer  2  is fabricated, the characteristic parameters of the digital printer  2  are stored in the data region  43 , and the initial values of the characteristic parameters are stored in the header  41  of the NVRAM  25 .  
         [0047]    [0047]FIG. 3 is a flow chart showing an example of the operation of the image forming apparatus according to the first embodiment of the present invention. Specifically, FIG. 3 shows the procedure for adjusting values of the parameters of the digital scanner  1  when the digital scanner  1  is connected to the digital printer  2  as an option after the digital scanner  1  and the digital printer  2  are shipped and in distribution.  
         [0048]    As illustrated in FIG. 3, in step S 31 , a user or a service person operates a panel on the digital printer  2  to select a mode for adjusting the values of the characteristic parameters of the digital scanner  1 . Upon that, the CPU  22  receives a signal from the panel indicating selection of the adjustment mode, and based on the signal, the CPU  22  displays a menu on the panel, allowing adjustment of the values of the characteristic parameters of the digital scanner  1 .  
         [0049]    In step S 32 , on the panel, the user or the service person selects a parameter of the digital scanner  1  which is to be adjusted.  
         [0050]    In step S 33 , the CPU  22  receives a signal from the panel indicating selection of the desired parameter, and based on the signal, the CPU  22 , via the controller  11 , reads the selected parameter from the data region  32  of the EEPROM  18 , in which the parameters of the digital scanner  1  are stored, and displays the value of the selected parameter on the panel.  
         [0051]    In step S 34 , the user or the service person inputs a new value of the selected parameter of the digital scanner  1  on the panel.  
         [0052]    In step S 35 , the CPU  22  stores the value of the selected parameter input from the panel in the RAM  24  temporarily.  
         [0053]    In step S 36 , the user or the service person is required to confirm that the change of the value of the selected parameter will really be made.  
         [0054]    In step S 37 , when it is confirmed that the change is to be made, the CPU  22  reads the value of parameter temporarily saved in the RAM  24 , and writes the value to the address of the selected parameter in the data region  32 .  
         [0055]    In step S 38 , after all desired parameters are adjusted following the above steps S 31  through S 37 , the user or the service person is required to make confirmation again, and the adjustment of the characteristic parameters of the digital scanner  1  is completed after the confirmation.  
         [0056]    In the above adjustments, when adjusting the values of the characteristic parameter of the digital scanner  1 , which is connected to the digital printer  2  to realize a digital duplicating machine after the digital scanner  1  and the digital printer  2  are shipped and in distribution, because the new values of the parameters are stored in the EEPROM  18 , which is a nonvolatile storage medium, the new values do not disappear even after the power is turned off, and thus the performance of the digital scanner  1  is ensured.  
         [0057]    According to the present embodiment, because the digital printer  2  and the digital scanner  1  are equipped with nonvolatile memories (EEPROM  18  and NVRAM  25 ), therefore, even after the digital scanner  1  and the digital printer  2  are shipped and in distribution, the function of a digital duplicating machine can be realized by connecting the digital scanner  1  to the digital printer  2 .  
         [0058]    Second Embodiment  
         [0059]    The image forming apparatus of the present embodiment has the same configuration as that described in the first embodiment with reference to FIG. 1. That is, using the same numeral references as in the first embodiment for the same components, the image forming apparatus of the second embodiment includes a digital scanner  1  and a digital printer  2  connected to each other, thus having the function of a digital duplicating machine. The digital scanner  1  has an EEPROM  18 , and the digital printer  2  has an NVRAM  25 , which are nonvolatile memories.  
         [0060]    The image forming apparatus of the present embodiment is different from that in the first embodiment in the aspect that one more data region is allocated in the NVRAM  25  of the digital printer  2  to store the characteristic parameters of the digital scanner  1 .  
         [0061]    [0061]FIGS. 4A and 4B are views of memory maps of the EEPROM  18  and the NVRAM  25 , respectively, of the image forming apparatus according to the second embodiment of the present invention.  
         [0062]    As illustrated in FIG. 4A, in the EEPROM  18 , for example, a header  31  is allocated in a region of a few bytes located from the address 0000H, and a data region  32  is allocated next to the header  31  to store the characteristic parameters of the digital scanner  1 .  
         [0063]    Similarly, as illustrated in FIG. 4B, in the NVRAM  25 , for example, a header  41  is allocated in a region of a few bytes located from the address 0000H. A data region  42  is allocated next to the header  41  for storing the characteristic parameters of the digital scanner  1 . Furthermore, a data region  43  is allocated next to the data region  42  for storing the characteristic parameters of the digital printer  2 .  
         [0064]    In the fabrication process of the digital scanner  1 , the characteristic parameters of the digital scanner  1  are stored in the data region  32 , and the initial values of the parameters are stored in the header  31  in the EEPROM  18 .  
         [0065]    Similarly, in the fabrication process of the digital printer  2 , the characteristic parameters of the digital printer  2  are stored in the data region  43 , and the initial values of the parameters are stored in the header  41  in the NVRAM  25 . In the fabrication process of the digital printer  2 , the data region  42  contains only certain initial values.  
         [0066]    [0066]FIG. 5 is a flow chart showing an example of the operation of the above image forming apparatus according to the present embodiment when power is turned on to start the image forming apparatus. One typical case as shown in FIG. 5 is the case in which the control section of the digital scanner  1  including the EEPROM  18  is exchanged, and thus, the characteristic parameters of the digital printer  2  have been written into the header  41  of the NVRAM  25 , but the data in the header  31  of the EEPROM  18  are still the initial values of the digital scanner  1 .  
         [0067]    In step S 51 , when it is confirmed that the digital scanner  1  has been connected to the digital printer  2 , the CPU  22  reads data from the header  41  of the NVRAM  25 .  
         [0068]    In step S 52 , the CPU  22  confirms whether the data read from the header  41  are the initial values of the parameters of the digital printer  2 .  
         [0069]    If the data read from the header  41  are the initial values of the parameters of the digital printer  2 , the routine proceeds to step S 53 , otherwise, the routine proceeds to step S 57 .  
         [0070]    In step S 53 , the CPU  22 , via the controller  11 , reads values of the characteristic parameters of the digital scanner  1  from the data region  32  in the EEPROM  18 , and saves the data to the RAM  24 .  
         [0071]    In step S 54 , the CPU  22  writes the values of the characteristic parameters of the digital scanner  1  saved in the RAM  24  to the data region  42  of the NVRAM  25 .  
         [0072]    In step S 55 , the CPU  22  writes the values of the characteristic parameters of the digital scanner  1  to the header  31  of the EEPROM  18  through the controller  11 .  
         [0073]    In step S 56 , at the same time with the step S 55 , the CPU  22  also writes the values of the characteristic parameters of the digital printer  2  to the header  41 . After that, the routine is completed.  
         [0074]    In step S 57 , if the data read from the header  41  are not the initial values of the parameters of the digital printer  2 , the CPU  22  reads data from the header  31  in the EEPROM  18  through the controller  11 .  
         [0075]    In step S 58 , the CPU  22  confirms whether the data read from the header  31  are the initial values of the parameters of the digital scanner  1 . If they are, the routine proceeds to step S 53 , and the operations in steps S 53  through S 56  are executed as described above. Otherwise, the routine is completed.  
         [0076]    By the above process, the characteristic parameters of the digital scanner  1  can be stored in the digital printer  2  in advance.  
         [0077]    [0077]FIG. 6 is a flow chart showing another example of the operation of the image forming apparatus according to the present embodiment. Specifically, FIG. 6 shows the procedure for adjusting values of the parameters of the digital scanner  1  when the digital scanner  1  is connected to the digital printer  2  as an option after the digital scanner  1  and the digital printer  2  are shipped and in distribution.  
         [0078]    As illustrated in FIG. 6, in step S 61 , a user or a service person operates a panel on the digital printer  2  to select a mode for adjusting the values of the characteristic parameters of the digital scanner  1 . Upon that, the CPU  22  receives a signal from the panel indicating selection of the adjustment mode, and based on the signal, the CPU  22  displays a menu on the panel, allowing adjustment of the values of the characteristic parameters of the digital scanner  1 .  
         [0079]    In step S 62 , on the panel, the user or the service person selects a parameter of the digital scanner  1  which is to be adjusted.  
         [0080]    In step S 63 , the CPU  22  receives a signal from the panel indicating selection of the desired parameter, and based on the signal, the CPU  22 , via the controller  11 , reads, the selected parameter from the data region  42  of the NVRAM  25 , in which the parameters of the digital scanner  1  are stored, and displays the value of the selected parameter on the panel.  
         [0081]    In step S 64 , the user or the service person inputs a new value of the selected parameter of the digital scanner  1  on the panel.  
         [0082]    In step S 65 , the CPU  22  stores the value of the selected parameter input from the panel to the RAM  24  temporarily.  
         [0083]    In step S 66 , the user or the service person is required to confirm that the change of the value of the selected parameter will really be made.  
         [0084]    In step S 67 , when it is confirmed that the change is to be made, the CPU  22  reads the value of parameter temporarily saved in the RAM  24 , and writes the value to the address of the selected parameter in the data region  42 .  
         [0085]    In step S 68 , after all desired parameters are adjusted following the above steps S 61  through S 67 , the user or the service person is required to make confirmation again, and the adjustment of the characteristic parameters of the digital scanner  1  is completed after the confirmation.  
         [0086]    Because of the above adjustments, when the digital printer  2  and the digital scanner  1  are connected to realize the function of a digital duplicating machine after the digital scanner  1  and the digital printer  2  are shipped and in distribution, it is possible to perform memory management for both the digital printer  2  and the digital scanner  1  on the digital printer  2  side.  
         [0087]    According to the present embodiment, when a digital scanner  1  is newly connected to the digital printer  2 , because the data of the characteristic parameters in the EEPROM  18  of the digital scanner  1  can be stored in the NVRAM  25  of the digital printer  2 , memory management for the digital printer  2  and the digital scanner  1  can be performed on the side of the digital printer  2 . In addition, when modifying the values of the parameters, because the corrected values can also be stored in the NVRAM  25  of the digital printer  2 , the performance of the digital scanner  1  is ensured.  
         [0088]    Third Embodiment  
         [0089]    The image forming apparatus of the present embodiment has the same configuration as that described in the first embodiment with reference to FIG. 1. That is, using the same numeral references as in the first embodiment for the same components, the image forming apparatus of the present embodiment includes a digital scanner  1  and a digital printer  2  connected to each other, thus having the function of a digital duplicate machine. The digital scanner  1  has an EEPROM  18 , and the digital printer  2  has an NVRAM  25 , which are nonvolatile memories.  
         [0090]    Furthermore, as illustrated in FIGS. 4A and 4B, a header  31  is allocated in the EEPROM  18 , and a data region  32  is allocated next for storing the characteristic parameters of the digital scanner  1 ; a header  41  is allocated in the NVRAM  25 , and a data region.  42  and a data region  43  are allocated in order for storing the characteristic parameters of the digital scanner  1  and the characteristic parameters of the digital printer  2 , respectively. Moreover, the characteristic parameters of the digital scanner  1  are stored into the data region  32 , and the initial values of the parameters are stored in the header  31  in the EEPROM  18  in the fabrication process of the digital scanner  1 ; and the characteristic parameters of the digital printer  2  are stored in the data region  43 , and the initial values of the parameters are stored in the header  41  in the NVRAM  25  in the fabrication process of the digital printer  2 . Further, the data region  42  contains certain initial values in fabrication.  
         [0091]    [0091]FIG. 7 is a flow chart showing an example of the operation of the image forming apparatus according to the third embodiment of the present invention. Specifically, FIG. 7 shows the procedure for adjusting values of the parameters of the digital scanner  1  when the digital scanner  1  is connected to the digital printer  2  as an option after the digital scanner  1  and the digital printer  2  are shipped and in distribution.  
         [0092]    As illustrated in FIG. 7, in step S 71 , a user or a service person operates a panel on the digital printer  2  to select a mode for adjusting the values of the characteristic parameters of the digital scanner  1 . Upon that, the CPU  22  receives a signal from the panel indicating selection of the adjustment mode, and based on the signal, the CPU  22  displays a menu on the panel, allowing adjustment of the values of the characteristic parameters of the digital scanner  1 .  
         [0093]    In step S 72 , on the panel, the user or the service person selects a parameter of the digital scanner  1  which is to be adjusted.  
         [0094]    In step S 73 , the CPU  22  receives a signal from the panel indicating selection of the desired parameter, and based on the signal, the CPU  22 , via the controller  11 , reads the selected parameter from the data region  42  of the NVRAM  25 , in which the parameters of the digital scanner  1  are stored, and displays the value of the selected parameter on the panel.  
         [0095]    In step S 74 , the user or the service person inputs a new value of the selected parameter of the digital scanner  1  on the panel.  
         [0096]    In step S 75 , the CPU  22  stores the value of the selected parameter input from the panel to the RAM  24  temporarily.  
         [0097]    In step S 76 , the user or the service person is required to confirm that the change of the value of the selected parameter will really be made.  
         [0098]    In step S 77 , when it is confirmed that the change is to be made, the CPU  22  reads the value of parameter temporarily saved in the RAM  24 , and writes the value to the address of the selected parameter in the data region  42  of the NVRAM  25 , and to the address of the parameter in the data region  32  of the EEPROM  18 .  
         [0099]    In step S 78 , after all desired parameters are adjusted following the above steps S 71  through S 77 , the user or the service person is required to make confirmation again, and the adjustment of the characteristic parameters of the digital scanner  1  is completed after the confirmation.  
         [0100]    Because of the above adjustments, when the digital printer  2  and the digital scanner  1  are connected to realize the function of a digital duplicating machine after the digital scanner  1  and the digital printer  2  are shipped and in distribution, it is possible to manage data stored in memories of both the digital printer  2  and the digital scanner  1  on the side of the digital printer  2 , and in addition, the adjusted parameters can also be stored in the digital scanner  1 . As a result, it is not necessary to adjust the characteristic parameters of the digital scanner  1  again even when the digital scanner  1  is connected to a different digital printer  2 .  
         [0101]    According to the present embodiment, in a digital duplicating machine including the digital scanner  1  and the digital printer  2  which are connected to each other, when the values of the characteristic parameters of the digital scanner  1  are changed, the new values of the characteristic parameters are stored in both the EEPROM  18  of the digital scanner  1  and the NVRAM  25  of the digital printer  2 , and therefore, memory management can be performed from the side of the digital printer  2 , and the performance of the digital scanner  1  is ensured. Furthermore, compatibility of the digital scanner  1  is ensured even when a different digital scanner is connected to the digital printer  2 .  
         [0102]    Fourth Embodiment  
         [0103]    The image forming apparatus of the present embodiment has the same configuration as that described in the first embodiment with reference to FIG. 1. That is, using the same numeral references as in the first embodiment for the same components, the image forming apparatus of the present embodiment includes a digital scanner  1  and a digital printer  2  connected to each other, thus having the function of a digital duplicating machine. The digital scanner  1  has an EEPROM  18 , and the digital printer  2  has an NVRAM  25 , which are nonvolatile memories.  
         [0104]    The image forming apparatus of the present embodiment is different from those of the previous embodiments in the aspect that corrections to the original values of the characteristic parameters of the digital scanner  1  are stored in the NVRAM  25 .  
         [0105]    [0105]FIGS. 8A and 8B are views of memory maps of the EEPROM  18  and NVRAM  25  of the image forming apparatus according to the fourth embodiment of the present invention.  
         [0106]    As illustrated in FIG. 8A, in the EEPROM  18 , for example, a header  31  is allocated in a region of a few bytes located from the address 0000H, and a data region  32  is allocated next to the header  31  to store the characteristic parameters of the digital scanner  1 .  
         [0107]    Similarly, as illustrated in FIG. 8B, in the NVRAM  25 , for example, a header  41  is allocated in a region of a few bytes located from the address 0000H, and a data region  44  is allocated next to the header  41  to store the corrections to the original values of the characteristic parameters of the digital scanner  1 . Furthermore, a data region  43  is allocated next to the data region  44  for storing the characteristic parameters of the digital printer  2 .  
         [0108]    In the fabrication process of the digital scanner  1 , the characteristic parameters of the digital scanner  1  are stored in the data region  32 , and the initial values of the parameters are stored in the header  31  in the EEPROM  18 .  
         [0109]    Similarly, in the fabrication process of the digital printer  2 , the characteristic parameters of the digital printer  2  are stored in the data region  43 , and the initial values of the parameters are stored in the header  41  in the NVRAM  25 . The initial values of the data region  44  are zero.  
         [0110]    [0110]FIG. 9 is a flow chart showing an example of the operation of the image forming apparatus according to the fourth embodiment of the present invention. Specifically, FIG. 9 shows the procedure for adjusting values of the parameters of the digital scanner  1  when the digital scanner  1  is connected to the digital printer  2  as an option after the digital scanner  1  and the digital printer  2  are shipped and in distribution.  
         [0111]    As illustrated in FIG. 9, in step S 91 , a user or a service person operates a panel on the digital printer  2  to select a mode for adjusting the values of the characteristic parameters of the digital scanner  1 . Upon that, the CPU  22  receives a signal from the panel indicating selection of the adjustment mode, and based on the signal, the CPU  22  displays a menu on the panel, allowing adjustment of the values of the characteristic parameters of the digital scanner  1 .  
         [0112]    In step S 92 , on the panel, the user or the service person selects a parameter of the digital scanner  1  which is to be adjusted.  
         [0113]    In step S 93 , the CPU  22  receives a signal from the panel indicating selection of the desired parameter, and based on the signal, the CPU  22 , via the controller  11 , reads the selected parameter from the data region  32  of the EEPROM  18 , in which the parameters of the digital scanner  1  are stored. In addition, the CPU  22  reads the correction to the original value of the selected parameter from the data region  44  of the NVRAM  25 , and makes calculations using the original value of the selected parameter and the correction to the original value, and the result is used as the present value of the selected parameter. Then the CPU  22  displays the present value of the selected parameter on the panel.  
         [0114]    Here, the calculation made by the CPU  22  may be the summation of the original value of the selected parameter stored in the EEPROM  18  and the correction to the original value of the selected parameter stored in NVRAM  25 , this sum giving the present value of the selected parameter.  
         [0115]    In step S 94 , the user or the service person inputs a new value of the selected parameter of the digital scanner  1  on the panel.  
         [0116]    In step S 95 , the CPU  22  calculates the difference between the new value of the selected parameter input from the panel and the value of the selected parameter stored in the EEPROM  18 , and stores the difference in the RAM  24  temporarily as the correction.  
         [0117]    In step S 96 , the user or the service person is required to confirm that the change of the value of the selected parameter will really be made.  
         [0118]    In step S 97 , when it is confirmed that the change is to be made, the CPU  22  reads the correction to the parameter temporarily saved in the RAM  24 , and writes the value of the correction to the corresponding address in the data region  44  of the NVRAM  25 .  
         [0119]    In step S 98 , after all desired parameters are adjusted in the same way following the above steps S 91  through S 97 , the user or the service person is required to make confirmation again, and the adjustment of the characteristic parameters of the digital scanner  1  is completed after the confirmation.  
         [0120]    Because of the above adjustments, when adjusting the characteristic parameters of the digital scanner  1  which is connected to the digital printer  2  to realize the function of a digital duplicating machine after the digital scanner  1  and the digital printer  2  are shipped and in distribution, it is not necessary to modify the original values of the characteristic parameters of the digital scanner  1  determined in the factory, but just store the corrections to the original values in the NVRAM  25  of the digital printer  2 . Therefore it is possible to maintain compatibility even when the digital scanner  1  is changed. Further, it is not necessary to adjust again the values of the characteristic parameters of the digital scanner  1 , and the values of the characteristic parameters determined previously based on the combination of the digital printer  2  and the former digital scanner  1  are still usable.  
         [0121]    According to the present embodiment, in a digital duplicating machine including the digital scanner  1  and the digital printer  2  that are connected to each other, because only the corrections to the original values are stored in the NVRAM  25  of the digital printer  2 , the performance of the digital scanner  1  is ensured. Furthermore, because values of the characteristic parameters determined in the factory are stored in the EEPROM  18  of the digital scanner  1 , compatibility of the digital scanner  1  is ensured even when a different digital scanner is connected to the digital printer  2 .  
         [0122]    Fifth Embodiment  
         [0123]    The image forming apparatus of the present embodiment has the same configuration as that described in the first embodiment with reference to FIG. 1. That is, using the same numeral references as in the first embodiment for the same components, the image forming apparatus of the present embodiment includes a digital scanner  1  and a digital printer  2  connected to each other, thus having the function of a digital duplicating machine. The digital scanner  1  has an EEPROM  18 , and the digital printer  2  has an NVRAM  25 , which are nonvolatile memories.  
         [0124]    However, the image forming apparatus of the present embodiment is different from those of the previous embodiments in the aspect that both the original values and the corrections to the original values of the characteristic parameters of the digital scanner  1  are stored in the NVRAM  25 .  
         [0125]    [0125]FIGS. 10A and 10B are views of memory maps of the EEPROM  18  and NVRAM  25 , respectively, of the image forming apparatus according to the fifth embodiment of the present invention.  
         [0126]    As illustrated in FIG. 10A, in the EEPROM  18 , for example, a header  31  is allocated in a region of a few bytes located from the address 0000H, and a data region  32  is allocated next to the header  31  to store the characteristic parameters of the digital scanner  1 .  
         [0127]    Similarly, as illustrated in FIG. 10B, in the NVRAM  25 , for example, a header  41  is allocated in a region of a few bytes located from the address 0000H, and data regions  42 ,  44 , and  43  are allocated next to the header  41  in order. The data regions  42  and  44  are used to store the original values and the corrections to the original values, respectively, of the characteristic parameters of the digital scanner  1 . The data region  43  is used to store the characteristic parameters of the digital printer  2 .  
         [0128]    In the fabrication process of the digital scanner  1 , the characteristic parameters of the digital scanner  1  are stored in the data region  32 , and the initial values of the parameters are stored in the header  31  in the EEPROM  18 .  
         [0129]    Similarly, in the fabrication process of the digital printer  2 , the characteristic parameters of the digital printer  2  are stored in the data region  43 , and the initial values of the parameters are stored in the header  41  in the NVRAM  25 . The initial values of the data region  44  are zero. In addition, the initial values of the characteristic parameters of the digital scanner  1  are stored in the data region  42  when the digital printer  2  is fabricated, and when the digital scanner  1  is connected to the digital printer  2 , data of the characteristic parameters of the digital scanner  1  stored in the data region  32  of the EEPROM  18  are transferred to the data region  42 , as described in the second embodiment.  
         [0130]    [0130]FIG. 11 is a flow chart showing an example of the operation of the image forming apparatus according to the fifth embodiment of the present invention. Specifically, FIG. 11 shows the procedure for adjusting values of the parameters of the digital scanner  1  when the digital scanner  1  is connected to the digital printer  2  as an option after the digital scanner  1  and the digital printer  2  are shipped and in distribution.  
         [0131]    As illustrated in FIG. 11, in step S 111 , a user or a service person operates a panel on the digital printer  2  to select a mode for adjusting the values of the characteristic parameters of the digital scanner  1 . Upon that, the CPU  22  receives a signal from the panel indicating selection of the adjustment mode, and based on the signal, the CPU  22  displays a menu on the panel, allowing adjustment of the values of the characteristic parameters of the digital scanner  1 .  
         [0132]    In step S 112 , on the panel, the user or the service person selects a parameter of the digital scanner  1  which is to be adjusted.  
         [0133]    In step S 113 , the CPU  22  receives a signal from the panel indicating selection of the desired parameter, and based on the signal, the CPU  22  reads the selected parameter from the data region  42  of the NVRAM  25 , in which the parameters of the digital scanner  1  are stored, and reads the correction to the original value of the selected parameter from the data region  44  of the NVRAM  25 . The CPU  22  makes calculations using the original value of the selected parameter and the correction to the original value, and the result is used as the present value of the selected parameter. Then the CPU  22  displays the present value of the selected parameter on the panel.  
         [0134]    For example, the calculation made by the CPU  22  may be the summation of the original value of the selected parameter stored in the data region  42  and the correction to the original value of the selected parameter stored in the data region  44  of the NVRAM  25 , this sum giving the present value of the selected parameter.  
         [0135]    In step S 114 , the user or the service person inputs a new value of the selected parameter of the digital scanner  1  on the panel.  
         [0136]    In step S 115 , the CPU  22  calculates the difference between the new value of the selected parameter input from the panel and the value of the selected parameter stored in the data region  42  of the NVRAM  25 , and stores the difference in the RAM  24  temporarily as the correction.  
         [0137]    In step S 116 , the user or the service person is required to confirm that the change of the value of the selected parameter will really be made.  
         [0138]    In step S 117 , when it is confirmed that the change is to be made, the CPU  22  reads the correction to the parameter temporarily saved in the RAM  24 , and writes the value of the correction to the corresponding address in the data region  44  of the NVRAM  25 .  
         [0139]    In step S 118 , after all desired parameters are adjusted in the same way following the above steps S 111  through S 117 , the user or the service person is required to make confirmation again, and the adjustment of the characteristic parameters of the digital scanner  1  is completed after the confirmation.  
         [0140]    Because of the above adjustments, when the digital printer  2  and the digital scanner  1  are connected to realize the function of a digital duplicating machine, it is possible to perform memory management for both the digital printer  2  and the digital scanner  1  on the digital printer  2  side.  
         [0141]    According to the present embodiment, in a digital duplicating machine including the digital scanner  1  and the digital printer  2  that are connected toh each other, when the characteristic parameters of the digital scanner  1  are modified, because only the corrections to the original values are stored in the NVRAM  25  of the digital printer  2 , the performance of the digital scanner  1  is ensured, and because values of the characteristic parameters determined in the factory are stored in the EEPROM  18  of the digital scanner  1  and the NVRAM  25 , compatibility of the digital scanner  1  is ensured even when the digital scanner is connected to a different digital printer  2 .  
         [0142]    Sixth Embodiment  
         [0143]    The image forming apparatus of the present embodiment has the same configuration as that described in the first embodiment with reference to FIG. 1. That is, using the same numeral references as in the first embodiment for the same components, the image forming apparatus of the present embodiment includes a digital scanner  1  and a digital printer  2  connected to each other, thus having the function of a digital duplicating machine. The digital scanner  1  has an EEPROM  18 , and the digital printer  2  has an NVRAM  25 , which are nonvolatile memories.  
         [0144]    However, the image forming apparatus of the present embodiment is different from those of the previous embodiments in the aspect that the original values and the corrections to the original values of the characteristic parameters of the digital scanner  1  are stored in both the EEPROM  18  and the NVRAM  25 .  
         [0145]    [0145]FIGS. 12A and 12B are views of memory maps of the EEPROM  18  and NVRAM  25  of the image forming apparatus according to the sixth embodiment of the present invention.  
         [0146]    As illustrated in FIG. 12A, in the EEPROM  18 , for example, a header  31  is allocated in a region of a few bytes located from the address 0000H, and a data region  32  is allocated next to the header  31  to store the original values of the characteristic parameters of the digital scanner  1 . Furthermore, a data region  33  is allocated next to the data region  32  to store the corrections to the original values of the characteristic parameters of the digital scanner  1 .  
         [0147]    Similarly, as illustrated in FIG. 12B, in the NVRAM  25 , for example, a header  41  is allocated in a region of a few bytes located from the address 0000H, and data regions  42 ,  44 , and  43  are allocated next to the header  41  in order. The data regions  42  and  44  are used to store the original values and the corrections to the original values, respectively, of the characteristic parameters of the digital scanner  1 ; the data region  43  is used to store the characteristic parameters of the digital printer  2 .  
         [0148]    In the fabrication process of the digital scanner  1 , the characteristic parameters of the digital scanner  1  are stored in the data region  32 , and the initial values of the parameters are stored in the header  31  in the EEPROM  18 . The initial values of the data region  33  are zero.  
         [0149]    Similarly, in the fabrication process of the digital printer  2 , the characteristic parameters of the digital printer  2  are stored in the data region  43 , and the initial values of the parameters are stored in the header  41  in the NVRAM  25 . The initial values of the data region  44  are zero. In addition, the initial values of the characteristic parameters of the digital scanner  1  are stored in the data region  42  when the digital printer  2  is shipped, and when the digital scanner  1  is connected to the digital printer  2 , data of the characteristic parameters of the digital scanner  1  stored in the data region  32  of the EEPROM  18  are transferred to the data region  42 , as described in the second embodiment.  
         [0150]    [0150]FIG. 13 is a flow chart showing an example of the operation of the image forming apparatus according to the fifth embodiment of the present invention. Specifically, FIG. 13 shows the procedure for adjusting values of the parameters of the digital scanner  1  when the digital scanner  1  is connected to the digital printer  2  as an option after the digital scanner  1  and the digital printer  2  are shipped and in distribution.  
         [0151]    As illustrated in FIG. 13, in step S 131 , a user or a service person operates a panel on the digital printer  2  to select a mode for adjusting the values of the characteristic parameters of the digital scanner  1 . Upon that, the CPU  22  receives a signal from the panel indicating selection of the adjustment mode, and based on the signal, the CPU  22  displays a menu on the panel, allowing adjustment of the values of the characteristic parameters of the digital scanner  1 .  
         [0152]    In step S 132 , on the panel, the user or the service person selects a parameter of the digital scanner  1  which is to be adjusted.  
         [0153]    In step S 133 , the CPU  22  receives a signal from the panel indicating selection of the desired parameter, and based on the signal, the CPU  22  reads the selected parameter from the data region  42  of the NVRAM  25 , in which the parameters of the digital scanner  1  are stored, and reads the correction to the original value of the selected parameter from the data region  44  of the NVRAM  25 . The CPU  22  makes calculations using the original value of the selected parameter and the correction to the original value, and the result is used as the present value of the selected parameter. Then the CPU  22  displays the present value of the selected parameter on the panel.  
         [0154]    For example, the calculation made by the CPU  22  may be the summation of the original value of the selected parameter stored in the data region  42  and the correction to the original value of the selected parameter stored in the data region  44  of the NVRAM  25 , this sum giving the present value of the selected parameter.  
         [0155]    In step S 134 , the user or the service person inputs a new value of the selected parameter of the digital scanner  1  on the panel.  
         [0156]    In step S 135 , the CPU  22  calculates the difference between the new value of the selected parameter input from the panel and the value of the selected parameter stored in the data region  42  of the NVRAM  25 , and temporarily stores the difference in the RAM  24  as the correction to the parameter.  
         [0157]    In step S 136 , the user or the service person is required to confirm that the change of the value of the selected parameter will really be made.  
         [0158]    In step S 137 , when it is confirmed that the change is to be made, the CPU  22  reads the correction to the parameter temporarily saved in the RAM  24 , and writes the value of the correction to the corresponding address in the data region  44  of the NVRAM  25 , and to the corresponding address in the data region  33  of the EEPROM  18 .  
         [0159]    In step S 138 , after all desired parameters are adjusted in the same way following the above steps S 131  through S 137 , the user or the service person is required to make confirmation again, and the adjustment of the characteristic parameters of the digital scanner  1  is completed after the confirmation.  
         [0160]    Because of the above adjustments, when the digital printer  2  and the digital scanner  1  are connected to realize the function of a digital duplicating machine, because the corrections to the characteristic parameters of the digital scanner  1  are stored in both the digital scanner  1  and the digital printer  2 , it is possible to maintain compatibility even when either the digital scanner  1  or the digital printer  2  is changed.  
         [0161]    According to the present embodiment, when a digital scanner  1  is newly connected to the digital printer  2 , because the data of the characteristic parameters of the digital scanner  1  are stored in the NVRAM  25  of the digital printer  2 , memory management for the digital printer  2  and the digital scanner  1  can be performed on the side of the digital printer  2 . In addition, when the values of the parameters of the digital scanner  1  are modified, because the corrections to the original values can be stored in both the NVRAM  25  of the digital printer  2  and the EEPROM  18  of the digital scanner  1 , the performance of the digital scanner  1  is ensured. Furthermore, because values of the characteristic parameters of the digital scanner  1  determined in the factory are stored in the EEPROM  18  of the digital scanner  1 , compatibility of the digital scanner  1  is ensured even when the digital scanner is connected to a different digital printer  2 . In addition, new adjustment of the parameters of the digital scanner  1  is not needed even if a digital scanner  1  is newly connected to a digital printer  2 .  
         [0162]    While the present invention has been described with reference to specific embodiments chosen for purpose of illustration, it should be apparent that the invention is not limited to these embodiments, but numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention.  
         [0163]    For example, the present invention is applicable to any kind of image forming apparatus, such as a fax machine as well as a digital printer, to which a digital scanner can be connected when necessary.  
         [0164]    Summarizing the effect of the present invention, because the digital printing device and the digital scanning device are equipped with nonvolatile memories, the functions of a digital duplicating machine can be realized by connecting the digital scanning device to the digital printing device even when the devices are in distribution after their shipment.  
         [0165]    In addition, because the data of the characteristic parameters of the digital scanning device are stored in the nonvolatile memory of the digital printing device, memory management for the two devices can be performed on the side of the digital printing device, and the performance of the digital scanning device is ensured. In addition, compatibility of the performance of the digital scanning device is ensured even when a different digital scanner is connected to the digital printer  2 .  
         [0166]    In addition, compatibility of the performance of the digital scanning device is ensured even when a different digital scanning device is newly connected to a different digital printing device, or when the digital scanning device is connected to a different digital printing device.  
         [0167]    Furthermore, it is not necessary to adjust values of the characteristic parameters of the digital scanning device, even when the digital scanning device is newly connected to the digital printing device.  
         [0168]    This patent application is based on Japanese priority patent application No. 2002-193658 filed on Jul. 2, 2002, the entire contents of which are hereby incorporated by reference.