Patent Publication Number: US-7710613-B2

Title: Image information apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present document incorporates by reference the entire contents of Japanese priority document, 2004-073005 filed in Japan on Mar. 15, 2004. 
   BACKGROUND OF THE INVENTION 
   1) Field of the Invention 
   The present invention relates to image information apparatuses such as digital copying machines, facsimile apparatuses, printers, scanners, network file servers, and digital multifunction products. 
   2) Description of the Related Art 
   Considerable progress has been made in recent years in the information processing related technology. Similarly, remarkable improvement has been made in the data transfer rates of large capacity storages, and the data compression ratios and the processing speeds of data compressing units. 
   It has become common to connect, as secondary storages, large and high-speed capacity storages to image information apparatuses. When such secondary storages are provided, it becomes possible to employ a configuration capable of inputting and outputting a plurality of image data in parallel. However, in this case, how efficiently the processing for storing (writing) image data in and reading image data from the secondary storage is performed becomes an important factor that decides the processing efficiency. 
   Assume that a variety of image inputting and outputting units are connected to an image information apparatus. In this case, it is difficult with the conventional memory control to maintain the processing efficiency by making the most of abilities of the secondary storage and the data compressing unit. One approach to solve this problem is to use a memory control system that employs a DMA for managing acquisition and release of resources for realizing maximum efficiency of use according to a processing ability of the secondary storage. 
   Precisely, in the conventional technique disclosed in Japanese Patent No. 2,950,962, images on a front side and a back side of an original are read in parallel, the image data of the front side and the image data of the back sides are connected by a unit of one line and stored in a buffer memory. The connected image data are separated into image data on the front side and image data on the back side when outputting the image data to the next stage. On the other hand, the image data can be output to the next stage as is, i.e., without separating. 
   Moreover, in the conventional technique disclosed in Japanese Patent Application Laid-open No. 2002-135544, images on a front side and a back side of an original are read in parallel, the image data of the front side and the image data of the back side are connected by a unit of one line. The connected image data is stored in a buffer memory (image memory), and simultaneously, read out and directly transferred to a hard disk. As a result, transfer of the image data to the hard disk can be started before writing of the image data in the buffer memory ends. 
     FIG. 10B  is an example of a structure of a conventional digital multifunction product. In this digital multifunction product, image data on a front side and a back side of an original are respectively transferred to a secondary storage in parallel through, for example, a peripheral component interconnect (PCI) bus. Precisely, each of image input devices  133  and  134 , which can be CCDs, read images on the front side and the back side of the original in parallel. The image data on the front side is stored in a frame memory  135   a  and the image data on the back side is stored in a frame memory  135   b.    
   A transfer unit  162  reads out, via a selector  161 , a predetermined amount of image data from the frame memory  135   a  with a delay of, for example, a predetermined time from the start of reading of the images by the image input devices  133  and  134 , and passes the read image data to a PCI transfer controller  152 . The PCI transfer controller  152  transfers the image data to a primary storage (which can be a semiconductor memory)  116  through a PCI bus. Next, the transfer unit  162  reads out, via the selector  161 , a predetermined amount of image data from the frame memory  135   b , and passes the image data to the PCI transfer controller  152 . The PCI transfer controller  152  transfers the image data to the primary storage  116  through the PCI bus. Thus, the transfer unit  162  first transfers the image data from the frame memory  135   a  to the PCI transfer controller  152  and then repeats the processing for transferring the image data from the frame memories  135   a  and  135   b  to the PCI transfer controller  152  alternately. 
   Thus, in the conventional technique, the image data from the frame memory  135   a  is transferred first to the PCI transfer controller  152 . Therefore, although the image data from the frame memory  135   b  is ready for transfer, if the image data from the frame memory  135   a  is not ready for transfer, transfer of the image data is not stated. In other words, although the PCI transfer controller can process transfer requests from plural request sources in parallel, the function is not fully utilized. 
   Thus, in the conventional techniques, most of the functions (parallel reading, reading speed, output speed, etc.) of the image input/output units are not fully used. 
   For example, when image reading units, which are capable of reading image data on both sides of an original in parallel, transfer the image data on the front and the back sides to a secondary storage side, the image reading units often transfer the image data read from the front and the back sides to the secondary storage sequentially for each side. This is because, although processing of image data is improved compared with that in the past, depending on a combination of image input/output units that execute processing for transferring image data to, storing image data in, and readout image data from the secondary storage side simultaneously, it is difficult to process plural image data in parallel because of a problem of speed. 
   However, taking into account freedom of structure, extension, and the like of an image information apparatus, a data transfer unit like a universal serial bus (USB) or a PCI is often used for a data transfer (transmission and reception) unit for inputting and outputting image data to and from the secondary storage side such that transfer of plural data can be executed by an identical transfer unit (e.g., the PCI transfer controller described above) simultaneously (in parallel). Under such circumstances, it is inevitable to transfer plural image data between the image information apparatus and the secondary storage in parallel. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to at least solve the problems in the conventional technology. 
   An image information apparatus according to an aspect of the present invention includes an least two image reading units, the image reading units read, in parallel, images on corresponding sides of a double-sided original and acquire image data of the corresponding sides; a primary storage unit that temporarily stores the image data of one or both the sides that is acquired by the image reading units; a secondary storage unit that receives the image data that is stored in the primary storage unit from the primary storage unit and stores the image data received; at least two transfer control units, each transfer control unit corresponds to an image reading unit, wherein the transfer control units transmit, in parallel and individually, the image data acquired by the corresponding image reading units to the primary storage unit via a communication path; and a communication control unit that controls transmission of data in the communication path from the transfer control units. 
   The other objects, features, and advantages of the present invention are specifically set forth in or will become apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic of a digital copying machine according to a first embodiment of the present invention; 
       FIG. 2  is a top view of an original stand of the digital copying machine shown in  FIG. 1 ; 
       FIG. 3  is a timing chart of operations of the digital copying machine shown in  FIG. 1 ; 
       FIG. 4  is a detailed structure of a storage unit shown in  FIG. 1 ; 
       FIG. 5  is a detailed structure of a memory control unit shown in  FIG. 4 ; 
       FIG. 6  is a software diagram of a digital copying machine according to a second embodiment of the present invention; 
       FIG. 7  is a hardware diagram of the digital copying machine according to the second embodiment; 
       FIG. 8  is a detailed structural diagram of a local memory and a controller shown in  FIG. 7 ; 
       FIG. 9  is a structural block diagram of an engine unit  124  shown in  FIG. 7 ; 
       FIG. 10A  is a schematic diagram of a digital multifunction product according to a first example of the present invention, and  FIG. 10B  is a schematic diagram of a digital multifunction product according to a conventional technique; 
       FIG. 11  is an example of a flowchart of the operations performed by the digital multifunction product shown in  FIG. 10A ; 
       FIG. 12  is another example of a flowchart of the operations performed by the digital multifunction product shown in  FIG. 10A ; 
       FIG. 13  is an example of a flowchart of the operations performed by a digital multifunction product according to a second example of the present invention; 
       FIG. 14  is another example of a flowchart of the operations performed by the digital multifunction product according to the second example; 
       FIG. 15  is still another example of a flowchart of the operations performed by the digital multifunction product according to the second example; 
       FIG. 16  is an example of a flowchart of the operations performed by a digital multifunction product according to a third example of the present invention; 
       FIG. 17  is another example of a flowchart of the operations performed by the digital multifunction product according to the third example; and 
       FIG. 18  is still another example of a flowchart of the operations performed by the digital multifunction product according to the third example. 
   

   DETAILED DESCRIPTION 
   Exemplary embodiments of the present invention are explained in detail below with reference to the accompanying drawings. Note that components and types, combinations, shapes, and relative positions of the components described in these embodiments are not meant to limit a scope of this explanation only to the types, combinations, shapes, and relative positions of the components unless specifically described otherwise and are simple explanatory examples. 
     FIG. 1  is a schematic of a digital copying machine according to a first embodiment of the present invention. The digital copying machine is only an example of the image information apparatuses, and the present invention is not limited to digital copying machines. 
   As shown in  FIG. 1 , the digital copying machine includes a reading unit that includes an original stand  11  for placing an original, an exposing lamp  12  that can move along the original stand  11 . The reading unit  1  optically scans a surface of an original, which is set on the original stand  11 , while the exposing lamp  12  exposes the surface of the original. Precisely, the reading unit  1  detects light reflected from of the surface of the original with a CCD (image sensor)  13  and performs photoelectric conversion to obtain an electric signal corresponding to the detected light. The reading unit  1  includes an imaging processing unit (IPU)  14  that applies various processings, such as shading correction, to the electric signal, subjects the electric signal to A/D conversion to obtain digital data of 8 bits, applies various image processings, such as magnification processing and dither processing, to the digital data to obtain image data, and sends the image data to an image forming unit  2  together with an image synchronization signal. 
     FIG. 2  is a top view of the original stand  11 . The original stand  11  is, for example, 12-inch wide in a main scanning direction and 17-inch long in a sub-scanning direction. 
   The reading unit  1  includes a scanner control unit  15  that detects various parameters by using various sensors to provide a control over a motor that drives the exposing lamp  12 . Moreover, the scanner control unit  15  sets various parameters in the IPU  14  so that the IPU  14  can optimally perform various processings. 
   The image forming unit  2  includes a rotating photosensitive member  22 . A charger  21  uniformly charges the photosensitive member  22 . A writing unit  23  modulates a laser beam based on the image data received from reading unit  1  and exposes the charged photosensitive member  22  with the modulated laser beam. As a result, an electrostatic latent image is formed on the photosensitive member  22 . A developing device  24  develops the electrostatic latent image with a toner to thereby visualize the electrostatic latent image and form a toner image. 
   The image forming unit  2  includes a sheet feeding tray  26 , a sheet feeding roller  25 , a registration roller  27 , a transfer charger  28 , and a separating charger  29 . The sheet feeding tray  26  houses transfer sheets (paper). The sheet feeding roller  25  picks up a transfer sheet from the sheet feeding tray  26 . The picked-up transfer sheet is conveyed to the registration roller  27  where it remains in a stand-by state. When the formation of the toner image on the photosensitive member  22  is complete, the transfer sheet that is in the stand-by state at the registration roller  27  is conveyed to the transfer charger  28 . As a result, the toner image on the photosensitive member  22  is transferred to the transfer sheet. The separating charger  29  separates the transfer sheet with the toner image from the photosensitive member  22 . The transfer sheet with the toner image is then conveyed to a fixing device  30 . The fixing device  30  fixes the toner image on the transfer sheet by applying heat and/or pressure to the toner image. A sheet discharging roller  31  conveys the transfer sheet with the toner image fixed to a sheet discharge tray  32  to discharge the transfer sheet out of the digital copying machine. 
   The image forming unit  2  includes a cleaning device  33  that is in pressed contact with the photosensitive member  22  and that removes any toner remaining on the photosensitive member  22  after the toner image is transferred to the transfer sheet. Subsequently, an electric-charge removing charger  34  removes any electric charge remaining on the photosensitive member  22 . A plotter control unit  35  performs detection by various sensors and control for a drive motor or the like to execute the process described above. 
     FIG. 3  is a timing chart of operations of the digital copying machine shown in  FIG. 1 . A frame gate signal (/FGATE) is a signal that represents an image effective range for an image area in the sub-scanning direction. Image data is made effective while this signal is at a low level. The /FGATE is asserted (brought into a state in which a signal is present) or negated (brought into a state in which a signal is absent) at a rising edge of a line synchronization signal (/LSYNC). 
   The /LSYNC is asserted by a predetermined clock at a rising edge of a pixel synchronization signal (PCLK) and, after the rising of this signal, image data in a main scanning direction is made effective after the predetermined clock. One image data is sent for one cycle of the PCLK and is divided into the number of data equivalent to 400 DPI with a position, where a range indicated by arrows in  FIG. 3  ends, as a starting point. The image data is sent as data of a luster format. A sub-scanning effective range of the image data usually depends on a size of the transfer sheet. 
   Returning to  FIG. 1 , a system control unit  3  detects a state input to an operation unit  4  by a user and, for example, sets various parameters in the reading unit  1 , the image forming unit  2 , a storage unit  5 , a facsimile (FAX) unit  6 , and an interface (I/F) unit  7  and instructs these units to execute processes. In addition, the system control unit  3  displays a state of an entire system on the operation unit  4 . Note that an instruction to the system control unit  3  is made by key input to the operation unit  4  by the user. 
   The FAX unit  6  encodes image data passed from the system control unit  3  based on a data transfer provision of G3 or G4 facsimile communication and sends the image data to a telephone line. In addition, the FAX unit  6  restores data transferred to the FAX unit  6  from the telephone line to change the data to binary image data and sends the image data to a writing unit  23  of the image forming unit  2 . 
   The I/F unit  7  sends data in the storage unit  5  to the outside and stores data received from the outside in the storage unit  5  according to an instruction from the system control unit  3 . 
   A selector unit  8  changes a state of a selector according to an instruction from the system control unit  3  and selects a source of image data at the time of image formation out of the reading unit  1 , the storage unit  5 , the FAX unit  6 , and the I/F unit  7 . 
   Since the storage unit  5  usually stores image data of an original input from the IPU  14 , the storage unit  5  is used for a copy application like remote copy or rotational copy. In addition, the storage unit  5  is also used as a buffer memory to temporarily store the binary image data from the FAX unit  6 . Moreover, the storage unit  5  is also used as means for storing peculiar information that is input from an input/output device via the I/F unit  7 . The system control unit  3  instructs the storage of the data. 
     FIG. 4  shows a detailed structure of the storage unit  5 . The storage unit  5  includes an image input/output DMA controller (DMAC)  51  and a memory control unit  52 . Although not shown, the image input/output DMAC  51  includes a CPU and a logical circuit. The image input/output DMAC  51  communicates with the memory control unit  52  to receive a command, performs operation setting corresponding to the command, and transmits a state of the image input/output DMAC  51  to the memory control unit  52  as status information. When the image input/output DMAC  51  receives a command for image input, the image input/output DMAC  51  packs input image data as memory data by a unit of eight pixels according to an input image synchronization signal and outputs the memory data to the memory control unit  52  together with a memory access signal as occasion arises. In addition, when the image input/output DMAC  51  receives a command for image output, the image input/output DMAC  51  outputs image data from the memory control unit  52  in synchronization with an output image synchronization signal. 
   The storage unit  5  includes an image memory  53  that stores image data. The image memory  53  can be a semiconductor storage element such as a DRAM. A total storage capacity of the image memory  53  is 16 megabytes consisting of 4 megabytes for an A3 size of 400 DPI binary image data, 4 megabytes as a capacity for electronic sort accumulation, 6 megabytes as a work area for data transfer, and 2 megabytes as an image data management area. The memory control unit  52  controls reading and writing of data in the image memory  53 . 
   Although not shown, the memory control unit  52  includes a CPU and a logical circuit. The memory control unit  52  receives commands from the system control unit  3 , performs operation setting corresponding to the commands, and transmits a state of the storage unit  5  to the system control unit  3  as status information. The operation commands include commands for image input, image output, compression, expansion, and the like. If the command relates to image input or image output, the memory control unit  52  transmits data to the image input/output DMAC  51 . If the command relates to compression, the memory control unit  52  transmits data to a compressing and expanding device  56  via an image transfer DMAC  54  or a code transfer DMAC  55 . 
     FIG. 5  is a detailed structure of the memory control unit  52 . The memory control unit  52  includes an input/output image address counter  61  that counts up according to an input/output memory access request signal. The input/output image address counter  61  outputs a 22-bit memory address that indicates the location of the input/output image data. Note that the address is initialized once at the start of memory access. 
   The memory control unit  52  includes a transfer image address counter  62  that counts up according to a transfer memory access permission signal. The transfer image address counter  62  outputs a 22-bit memory address that indicates the location of the transfer image. Note that the address is initialized once at the start of memory access. 
   When a semiconductor memory is used as a buffer at the time of image input, the system control unit  3  sets a value for comparing a difference between input processing lines and transfer lines, which is outputted from a difference calculating unit  65 , in a difference comparing unit  64 . Note that, at the time of image input, the difference calculating unit  65  subtracts the number of input/output processing lines outputted by the image input/output DMAC  51  from the number of transfer processing lines outputted by the compressing and expanding device  56  and outputs a result of the subtraction to the difference comparing unit  64 . 
   At the time of image input, the difference comparing unit  64  compares the number of difference lines outputted by the difference calculating unit  65  and a set value outputted by the line setting unit  63 , outputs an error signal when the number of difference lines is equal to the set value. When the number of difference line is zero, the difference comparing unit  64  activates a transfer request mask signal for a comparison result signal that is outputted to an arbiter  66 . Otherwise, or in a state in which an input/output image is not under operation, the difference comparing unit  64  does not output the active transfer request mask signal. The arbiter  66  outputs a memory access permission signal for access by the compressing and expanding device  56 . The arbiter  66  outputs the memory access permission signal under conditions that an address comparison signal is active and an input/output memory access signal is inactive. 
   An address selector  67  is a selector that is selected by the arbiter  66 . An address of an input image or a transfer image is selected. A request mask  68  masks (i.e., brings into a disenable state) a transfer memory access request signal for access by the compressing and expanding device  56  according to a result of comparison by the difference comparing unit  64  and stops transfer processing. 
   An access control circuit  69  divides an inputted physical address into a row address and a column address corresponding to an image memory (e.g., DRAM)  53  and outputs the addresses to an address bus of 11 bits. In addition, the access control circuit  69  outputs DRAM control signals (RAS, CAS, WE, etc.) according to an access start signal from the arbiter  66 . 
   The storage unit  5  is initialized by an image input instruction from the system control unit  3  and comes into an image data pending state. When the reading unit  1  operates to input image data to the storage unit  5 , the memory control unit  52  writes the image data in the image memory  53  once. In that case, the memory control unit  52  counts the number of processing lines of the written image data with the image input/output DMAC  51 . At this point, the compressing and expanding device  56  outputs a transfer memory access request signal in response to a command for image transfer. However, since the request signal is masked by the request mask unit  68  in the memory control unit  52 , actual memory access is not performed. Thereafter, data input for one line from the image input/output DMAC  51  ends, whereby the mask for the transfer memory access request signal is released, the image data is read out from the image memory  53 , and an operation for transferring the image data to the compressing and expanding device  56  is started. During this operation, the difference calculating unit  65  calculates a difference between the numbers of the two processing lines and, if the difference is zero, the request mask unit  68  masks the transfer memory access request signal such that overtaking of an address does not occur. 
   The image transfer DMAC  54  includes a CPU and a logical circuit. The image transfer DMAC  54  communicates with the memory control unit  52  to receive a command, performs operation setting corresponding to the command, and transmits status information for informing the memory control unit  52  of a state of the image transfer DMAC  54 . When the image transfer DMAC  54  receives a command for compression, the image transfer DMAC  54  outputs a memory access request signal to the memory control unit  52 . When a memory access permission signal is active, the image transfer DMAC  54  receives image data and transfers the image data to the compressing and expanding device  56 . The image transfer DMAC  54  incorporates an address counter, which counts up according to the memory access request signal, and outputs a memory address of 22 bits indicating a storage place where the image data is stored. 
   The code transfer DMAC  55  includes a CPU and a logical circuit. The code transfer DMAC  55  communicates with the memory control unit  52  to receive a command, performs operation setting corresponding to the command, and transmits status signal for informing the memory control unit  52  of a state of the code transfer DMAC  55 . When the code transfer DMAC  55  receives a command for expansion, the code transfer DMAC  55  outputs a memory access request signal to the memory control unit  52 . When a memory access permission signal is active, the code transfer DMAC  55  receives image data and transfers the image data to the compressing and expanding device  56 . The code transfer DMAC  55  incorporates an address counter, which counts up according to the memory access request signal, and outputs a memory address of 22 bits indicating a storage place where the image data is stored. 
   The compressing and expanding device  56  includes a CPU and a logical circuit. The compressing and expanding device  56  communicates with the memory control unit  52  to receive a command, performs operation setting corresponding to the command, and transmits status information for informing the memory control unit  52  of a state of the compressing and expanding device  56 . In addition, the compressing and expanding device  56  processes binary data with an MH encoding method. 
   An HDD controller  57  includes a CPU and a logical circuit. The HDD controller  57  communicates with the memory control unit  52  to receive a command and performs operation setting corresponding to the command. In addition, the HDD controller  57  transmits status information for informing the memory control unit  52  of a state of a hard disk storage (HDD)  58  serving as a secondary storage, obtains a status from the HDD  58 , and performs data transfer with the HDD  58 . 
   As an operation of the entire storage unit  5 , in the case of image input and data accumulation, the image input/output DMAC  51  writes image data in a predetermined image area of the image memory  53 . On the other hand, the image input/output DMAC  51  reads out the image data from the image memory  53 . At this point, the image transfer DMAC  54  counts the number of image lines. 
   In the first embodiment, for example, image reading units described in claims are realized by the image reading units  1 , a primary storage unit described in claims is realized by the image memory  53 , a secondary storage unit described in claims is realized by the HDD  58 , and transfer control units described in claims is realized by the memory control unit  52 , the image transfer DMAC  54 , the code transfer DMAC  55 , and the like. 
   When an image is read, read one image data is stored entirely or partially in the image memory  53 . The image transfer DMAC  54  transfers the image data to the compressing and expanding device  56 . The compressing and expanding device  56  compresses the image data according to MH encoding and the code transfer DMAC  55  transfers the encoded image data to the HDD  58 . 
     FIG. 6  is a software diagram of a digital multifunction product according to a second embodiment of the present invention. Note that, here, an image information apparatus, in which functions of apparatuses like a printer, a copying machine, a facsimile apparatus, and a scanner are housed in one housing, is referred to as a digital multifunction product (hereinafter, “multifunction product”). 
   This multifunction product includes a program (software) group  71  consisting of an application program group  74  and a platform program group  75 , a starting unit  72 , and hardware resources  73 . When power is supplied to the multifunction product, the starting unit  72  operates first to start the application program group  74  and the platform program group  75 . For example, the starting unit  72  reads out the application program group  74  and the platform program  75  from a hard disk storage (HDD) or the like serving as the secondary storage unit, transfers the read-out computer programs to a memory area, and starts the computer programs. The hardware resources  73  include a black and white laser printer (B&amp;W LP)  76 , a color laser printer (Color LP)  77 , and other hardware resources  78  like a scanner and a facsimile apparatus. Moreover, although not shown, the hardware resources  73  include a CPU, a semiconductor memory, and various logical circuits to be described later, which are hardware resources, as an operation environment of the program group  71 . 
   The application program group  74  includes computer programs for performing processing peculiar to user services for image reading and image formation, respectively, like a printer application  81 , a copy application  82 , a facsimile application  83 , and a scanner application  84 . 
   The platform program group  75  includes control service programs  79  for interpreting a processing request from the application program  74  and issuing an acquisition request for the hardware resources  73  and a system resource manager (SRM)  86  for managing one or more hardware resources  73  and arbitrating the acquisition request from the control service programs  79 . 
   The control service programs  79  include an operation panel control service program (OCS)  93 , a facsimile control service program (FCS)  94 , an engine control service program (ECS)  95 , and a system control service program (SCS)  98 . The platform program group  75  includes an application interface (API)  90  for receiving a processing request from the application program group  74  according to a function defined in advance. 
   The SRM  86  and an FCUH  99  use functions defined in advance to send a processing request to the hardware resources  73  via an engine I/F  101 . 
   In this multifunction product, it is possible to perform processing commonly required by the respective application programs with the platform program group  75  unitarily. 
     FIG. 7  is a hardware diagram of the multifunction product according to the second embodiment. The multifunction product includes a controller  110 , an operation panel  120 , an FCU  121 , a USB device  122 , an IEEE1394 device  123 , and an engine unit  124 . The controller  110  includes a CPU  111 , a system memory (MEM-P)  112 , a north bridge (NB)  113 , a south bridge (SB)  114 , and an application specific integrated circuit (ASIC)  115 , a local memory (MEM-C)  116  serving as a primary storage unit, and an HDD  117  serving as a secondary storage unit. The operation panel  120  is connected to the ASIC  115  in the controller  110 . The FCU  121 , the USB device  122 , the IEEE1394 device  123 , the engine unit  124  serving as an image input/output unit, and the like are connected to the ASIC  115  via a PCI bus. 
   In the controller  110 , the local memory  116  and the HDD  117  are connected to the ASIC  115 , and the CPU  111  and the ASIC  115  are connected via the NB  113 . If the CPU  111  and the ASIC  115  are connected via the NB  113  in this way, it is possible to cope with a case in which an interface of the CPU  111  is not made public. Note that the ASIC  115  and the NB  113  are connected via an accelerated graphics port (AGP)  118  instead of the PCI bus. The ASIC  115  and the NB  113  are connected via the AGP  118  instead of the low-speed PCI bus in this way, whereby decline in performance is prevented when one or more processes (computer programs) constituting the application program group  74  and the platform program group  75  shown in  FIG. 6  are controlled to be executed. 
   The CPU  111  controls the entire multifunction product. The CPU  111  starts and executes the SRM  86 , the OCS  93 , the FCS  94 , the ECS  95 , an MCS  96 , the SCS  98 , the FCUH  99 , and an IMH  100  shown in  FIG. 6  on an OS as processes. The CPU  111  also starts and executes the printer application  81 , the copy application  82 , the facsimile application  83 , the scanner application  84 , and the like constituting the application programs  74 . 
   The NB  113  is a bridge for connecting the CPU  111 , the system memory  112 , the SB  114 , and the ASIC  115 . The system memory  112  is a memory that is used as a memory for drawing or the like of this multifunction product. The SB  114  is a bridge for connecting the NB  113  with a ROM (not shown in the figure), the PCI bus, and peripheral devices. The local memory  116  is a memory that is used as an image buffer for copy and a code buffer. 
   The ASIC  115  is an integrated circuit dedicated for an image processing application that has a hardware element for image processing. The HDD  117  is a secondary storage for storing image data, document data, computer programs, font data, forms, and the like. The operation panel  120  is an operation unit that receives input operation from a user and performs display for the user. The ASIC  115  has a DMA transfer function for transferring image data and performs DMA transfer with the engine unit  124  via the PCI bus. 
   Specifically, as shown in  FIG. 8 , the controller  110  includes two channels of video input DMA controllers (DMACs) and a video output DMA controller in the ASIC  115  and can perform video data transfer of a scanner input  1 , a scanner input  2 , and a plotter output in parallel. For example, when the controller  110  transfers image data on both sides of an original read by a scanner to the local memory  116  simultaneously (in parallel), in response to a request sent from the SRM  86 , the IMH  100  secures a memory equivalent to transfer image sizes in the local memory  116  and sets transfer image sizes Xw and Yw and an address of the secured memory in the video input DMA controller in the ASIC  115  to thereby make it possible to transfer the image data. 
     FIG. 9  is a structural block diagram of the engine unit  124  at the time when simultaneous reading of front and back sides of a double-sided original is realized. 
   In the engine unit  124 , an image data control IF controller (hereinafter, “controller”)  131  is directly controlled by a CPU  132 . The controller  131  includes image input devices  133  and  134  such as CCDs, a DRAM  135  that is a frame memory for temporarily storing an input signal, and a GAVD  136  that is an output device. The controller  131  is connected to a data bus like a PCI and is capable of outputting input data to the secondary storage (an external storage, the HDD  117 ) side and inputting output data from the secondary storage side. Image input devices  133  and  134  are image reading elements such as CCDs and reads images from both sides of an original simultaneously (in parallel). 
   The frame memory  135  stores image data from the image input devices  133  and  134  temporarily. Using this frame memory  135 , the controller  131  adjusts timing for inputting image data on front and back sides of an original at the time when both the sides are read simultaneously and a data transfer rate for transferring data to the PCI bus. Note that the image data on the front and the back sides are written in different continuous areas in the frame memory  135 , respectively. A DRAM controller  140  performs addressing at the time of the writing. Transfer units  151   a  and  151   b  corresponding to the front and the back sides include buffer memories. The transfer units  151   a  and  151   b  capture image data on the front side or image data on the back side for each unit of transfer and pass the image data to the PCI transfer controller  152 . 
   In the second embodiment, for example, the image reading units described in claims are realized by the engine unit  124 , the primary storage unit described in claims is realized by the local memory, the secondary storage unit described in claims is realized by the HDD  117 , the transfer control units described in claims is realized by the transfer unit  151 , the communication control unit described in claims is realized by the PCI transfer controller  152  and the PCI interface  153 , and the selecting unit described in claims is realized by the CPU  132  or the like. 
   Concrete examples of the second embodiment are explained below in detail. 
   It is assumed that, in the multifunction product according to the second embodiment, it is possible to execute writing of input image data in the frame memories  135  and readout of input image data from the frame memories  135  in parallel and, when reading of both sides is executed, it is possible to execute writing of front side image data and writing of back side image data in the frame memories  135  in parallel. 
   First, a data flow at the time when images on an original are read will be explained with reference to  FIG. 9 . Note that an image reading operation is divided into two operations: 
   (1) An operation for writing image data, which are inputted by the image input devices  133  and  134 , in the frame memory  135  in parallel, and 
   (2) An operation for reading out the image data on front and back sides of an original stored in the frame memory  135  in parallel, subjecting the image data to image processing like data compression (data conversion), transferring the image data to the local memory  116  in parallel via a data bus, and storing the image data in the HDD  117 . 
   However, depending on a structure of the multifunction product, when the multifunction product does not include a frame memory or a memory capacity of a frame memory is small, it is also possible to transfer the image data directly to the data bus without dividing the image reading operation into the two operations (1) and (2). 
   The operation (1) will be hereinafter explained with reading of image data on the front side as an example. First, an image signal inputted from the image input device  133  for display is inputted to an image data input IF  138  via a shading processing unit  200 . Then, the image data (image signal) is transferred to the frame memory  135  via the DRAM controller  140 . The DRAM controller  140  addresses the inputted image data and sequentially writes and stores the inputted image data in continuous area for front side data in the frame memory  135 . 
   Next, the operation (2) will be explained. First, the transfer unit  151   a  transfers image data for a unit of transfer in the image data on the front side stored in the frame memory  135  to the PCI transfer controller  152  via the image data processing unit  141  to  145 . Then, the PCI transfer controller  152  transfers the transferred data to the local memory  116  via the PCI data bus and saves the data in the HDD  117 . Note that, as the image data processing unit, there are mask processing units  141  and  146 , filter processing units  142  and  147 , magnification processing units  143  and  148 , area expansion/reduction processing units  144  and  149 , image compression processing units  145  and  150 , and the like. The PCI transfer controller  152  transfers two image data, which the respective transfer units  151  requests to transfer, to the local memory  116  through the PCI data bus. In this case, for each image data, the PCI transfer controller  152  can set a data capacity and an image data transfer rate necessary for outputting the image data to the local memory  116 . In addition, the PCI transfer controller  152  performs channel setting such that a transfer destination via the PCI bus is set to, for example, a DMAC  1  or a DMAC  2  (see  FIG. 8 ). 
     FIGS. 10A and 10B  are structural block diagrams of a portion, which extends from the frame memories  135  to the local memory (the fist storage unit)  116  and the HDD (the second storage unit) through the PCI bus, shown as a model.  FIG. 10A  is a structural block diagram of the first embodiment and  FIG. 10B  is a structure block diagram of a conventional technique that is used for the purpose of comparison. In the structure shown in  FIG. 10A , in first embodiment, a single data path (a communication path) like a PCI bus (which may be a USB) is used in a portion for executing image data transfer, and plural image data are mixed by plural channels to make it possible to transmit and receive the image data bit-serially and add a channel for data transfer relatively easily. 
   It is assumed that input start timing, a data capacity, a transfer rate, and the like of image data, which are inputted by the image input devices  133  and  134  such as CCDs, may be different depending on a physical arrangement of the image input devices  133  and  134 . Therefore, the two transfer units  151   a  and  151   b , which carry out transfer of image data on front and back sides of an original, are provided and data transfer processes (computer programs) for the front and the back sides to be described later are associated with the front and the back sides, respectively, such that the PCI transfer controller  152  can receive transfer requests from both the transfer units  151   a  and  151   b  in parallel. Thus, the PCI transfer controller  152  performs transfer processing for the image data asynchronously for each image data on the front and the back sides. The PCI transfer controller  152  not only transfers plural image data simultaneously and synchronously but also transfer the image data individually, asynchronously, and in parallel (in the same period). With such a structure, it is possible to change a method of transferring image data easily according to a function of reading a double-sided original, a data transfer rate, and timing for reading image data. 
     FIG. 11  is an example of a flowchart of the operations performed by the digital multifunction product shown in  FIG. 10A . These operations relate to reading image data from an original. These operations are programmed as processes (consisting of computer programs) in the scanner application  84  and the engine unit  124 . The CPU  111  sends a request to the engine unit  124  using the platform program  75  such as the SRM  86  and the ECS  95  according to the scanner application  84 . The CPU  132  in the engine unit  124  continues to execute this operation flow according to the request. 
   First, with the operation panel  120 , a user instructs the multifunction product to perform simultaneous reading of both sides, and the CPU  111  recognizes the instruction and notifies the CPU  132  in the engine unit  124  of contents of the instruction (step S 1 ). Consequently, to read image data on front and back sides of an original in parallel, the CPU  132  starts a front side reading process (step S 3 ) and a back side reading process (step S 6 ) that are executed by the CPU  132  itself. The CPU  132  also starts data transfer processes (see  FIG. 12 ) for the front and the back sides, respectively. Concretely, in the front side reading process, when the original is conveyed to a predetermined position (“Yes” in step S 2 ), the CPU  132  starts the front side reading and the DRAM controller  140  stores the image data in the frame memory  135   a  (step S 3 ). 
   When the transfer of the image data on the front side ends (“Yes” in step S 4 ), the CPU  132  ends the front side reading process. 
   On the other hand, in the back side reading process, when the original is conveyed to a predetermined reading position (“Yes” in step S 5 ), the CPU  132  starts the back side reading and the DRAM controller  140  stores the image data on the back side in the frame memory  135   b  in parallel with the storage of the image data on the front side (step S 6 ). 
   When the transfer of the image data to the local memory  116  ends (“Yes” at step S 7 ), the CPU  132  judges whether the data transfer for the front side has ended and, if the data transfer for the front side has ended, and checks whether next original is present (step S 8 ). If the next original is present (“Yes” at step S 8 ), the CPU  132  repeats the steps S 1  to S 8  for the next original. If no next original is present, the CPU  132  ends the process. 
     FIG. 12  is another example of a flowchart of the operations performed by the digital multifunction product shown in  FIG. 10A . These operations relate to reading image data on respective sides and transferring the image data. 
   First, in the reading process, after starting the process, the CPU  132  starts reading of a front side (or a back side) of an original if the original is conveyed to a predetermined reading position (step S 11 ), and the DRAM controller  140  stores read image data in the frame memory  135 . Then, when the original is read to a reading end position of the original and the reading of the image data on the front side (or the back side) ends (“Yes” at step S 12 ), the CPU  132  ends the reading process. 
   On the other hand, in the data transfer process for transferring image data on a front and a back sides of an original, after starting the process, the CPU  132  judges whether the conditions for starting the data transfer is satisfied and, if the condition is not satisfied, waits until the condition is satisfied (step S 13 ). Note that it is assumed that the conditions for starting the data transfer are set in advance. The data transfer can be started, for example, just after the image reading process is started, or when the number of lines written in a frame memory reaches a predetermined value. 
   If the condition for staring the data transfer is satisfied (“Yes” at step S 13 ), the CPU  132  starts the data transfer (step S 14 ). Specifically, the DRAM controller  140  reads out image data on a corresponding side, which are stored in the frame memory  135 , in order from the top. On the front side, the respective image data processing units  141  to  145  (on the back side, the respective image data processing units  146  to  150 ) apply image processing to the image data. On the front side, the transfer unit  151   a  (on the back side, the transfer unit  151   b ) sequentially captures the image data and passes the image data to the PCI transfer controller  152 . Then, the PCI transfer controller  152  transfers the passed image data from the respective transfer units  151  to the local memory  116  through the PCI bus according to a transfer request using a channel, in which the DMAC  1  or the DMAC  2  is set as a destination, properly. 
   Thereafter, the CPU  132  continues the process until the transfer of the front side data (or the back side data) ends (step S 15 ). When the transfer ends (“Yes” at step S 15 ), the CPU  132  ends the front side or the back side data transfer process. 
   In this way, according to the first example, when a double-sided original parallel reading unit is connected as an image input unit, it is possible not only to transfer image data on both sides of an original to the local memory serving as the primary storage unit in parallel but also to transfer the image data at arbitrary timing without adjusting the timing to transfer timing of the image data on the other side. 
   A second embodiment relates to a structure, when image data on both sides of an original are transferred to the local memory, that makes it is possible to select whether the image data on both the sides are to be transferred in parallel or transferred in time series. 
     FIG. 13  is an example of a flowchart of the operations performed by a digital multifunction product according to a second example of the present invention. These operations relate to reading image data from an original. These operations are programmed as processes (computer programs) in the scanner application  84  and the engine unit  124 . The CPU  111  sends a request to the engine unit  124  using the platform program  75  such as the SRM  86  and the ECS  95  according to the scanner application  84 . The CPU  132  in the engine unit  124  continues to execute this operation flow according to the request. 
   First, with the operation panel  120  a user instructs the multifunction product to perform simultaneous reading of both sides, and the CPU  111 , which recognizes the instruction, notifies the CPU  132  in the engine unit  124  to that effect and also notifies the CPU  132  of a size of an unused area or the like of the local memory  116  (step S 21 ). Consequently, the CPU  132  resets a front side reading end flag (UpsideReadFlag) in the DRAM  155  and stores the size of the unused area of the local memory  116  in the DRAM  155  (step S 22 ). 
   Subsequently, to read image data on front and back sides of an original in parallel, the CPU  132  starts a front side reading process and a back side reading process that are executed by the CPU  132  itself. The CPU  132  also starts data transfer processes for the front and the back sides shown in  FIGS. 14 and 15 . Then, in the front side reading process, when the original is conveyed to a predetermined position (“Yes” at step S 23 ), the CPU  132  starts front side reading and the DRAM controller  140  stores the image data in the frame memory  135  (step S 24 ). 
   When the reading of the image data on the front side and transfer of the image data on the front side to be described later end (“Yes” at step S 25 ), the CPU  132  ends this front side reading process. 
   On the other hand, in the back side reading process, when the original is conveyed to a predetermined reading position (“Yes” at step S 26 ), the CPU  132  starts back side reading and the DRAM controller  140  stores the image data on the back side in the frame memory  135  in parallel with the storage of the image data on the front side (step S 27 ). 
   When the reading of the image data on the back side and transfer of the image data on the back side to the local memory  116  according to a back side data transfer process to be described later end in this way (“Yes” at step S 28 ), the CPU  132  judges whether a front side reading end flag, which is set by the front side data transfer process, is set. If the front side reading end flag is set, the CPU  132  confirms presence of the next original (step S 29 ). Then, if the next original is present (“Yes” at step S 29 ), the CPU  132  executes the simultaneous reading of both sides again. If no next original is present, the CPU  132  ends the process. 
     FIG. 14  is another example of a flowchart of the operations performed by the digital multifunction product according to the second example. These operations relate to reading image data from respective sides of the original and transferring the image data. 
   First, in the front side reading process, after starting the process, the CPU  132  starts front side reading when an original is conveyed to a predetermined reading position (step S 31 ) and the DRAM controller  140  stores read image data in the frame memory  135 . Then, when the original is read to a reading end position of the original and the reading of the image data on the front side ends (“Yes” at step S 32 ), the CPU  132  ends the front side reading process. 
   On the other hand, in the front side data transfer process, after starting the process, the CPU  132  waits until the condition for starting the data transfer is satisfied (step S 33 ). Note that it is assumed that the conditions for starting the data transfer are set in advance. The data transfer can be started, for example, just after the image reading process is started, or when the number of lines written in a frame memory reaches a predetermined value. 
   If the condition for staring the data transfer is satisfied (“Yes” at step S 33 ), the CPU  132  starts the data transfer (step S 34 ). More specifically, the DRAM controller  140  reads out image data on the front side, which are stored in the frame memory  135 , in order from the top. The respective image data processing units  141  to  145  apply image processing to the image data. The transfer unit  151   a  sequentially captures the image data and passes the image data to the PCI transfer controller  152  for each unit of transfer. Then, the PCI transfer controller  152  transfers the passed image data to the local memory  116  through the PCI bus using a channel in which the DMAC  1  is set as a destination. Thereafter, the CPU  132  continues the process until the transfer of the front side data ends (step S 35 ) and, when the transfer ends (“Yes” at step S 35 ), sets a front side reading end flag (UpsideReadFlag) (step S 36 ). 
   Next, an outline of an operation flow of the back side reading process and an operation flow of the back side data transfer process will be explained with reference to  FIG. 15 . 
   First, in the back side reading process, after starting the process, the CPU  132  starts back side reading when an original is conveyed to a predetermined reading position (step S 41 ) and the DRAM controller  140  stores read image data in the frame memory  135 . Then, when the original is read to a reading end position of the original and the reading of the image data on the back side ends (“Yes” at step S 42 ), the CPU  132  ends the back side reading process. 
   On the other hand, in the back side data transfer process, after starting the process, the CPU  132  waits until the condition for starting the data transfer is satisfied (step S 43 ). Note that it is assumed that the conditions for starting the data transfer are set in advance. The data transfer can be started, for example, just after the image reading process is started, or when the number of lines written in a frame memory reaches a predetermined value. 
   If the condition for staring the data transfer is satisfied (step S 43 ), the CPU  132  judges whether the image data are to be transferred in parallel or sequentially (step S 44 ). For example, when a size of an unused area of the local memory  116  stored in the DRAM  155  is small and the image data overflow from the local memory  116  in a transfer destination if the image data are transferred in parallel or when there is only one unused channel in a bus, the CPU  132  judges that the image data cannot be transferred in parallel. Therefore, in such a case, the CPU  132  judges that the image data are to be transferred sequentially (“Yes” at step S 44 ) and waits until a front side reading end flag (UpsideReadFlag) is set. 
   On the other hand, when the parallel transfer is possible or when the front side reading end flag is set (“No” at step S 44 ), the CPU  132  starts data transfer (step S 45 ). More specifically, the DRAM controller  140  reads out the image data on the back side stored in the frame memory  135  in order from the top, the respective image data processing units  146  to  150  apply image processing to the image data, and the transfer unit  151   b  sequentially captures the image data and passes the image data to the PCI transfer controller  152  for each unit of transfer. Then, the PCI transfer controller  152  transfers the image data to the local memory  116  through the PCI bus using a channel in which the DMAC  2  is set as a destination. Thereafter, the CPU  132  continues the process until the transfer of the back side data ends (step S 46 ) and, when the transfer ends (“Yes” at step S 46 ), ends the back side data transfer process. 
   In this way, according to second example, when image data read from both sides of an original in parallel are to be transferred to a secondary storage, it is possible to select the parallel transfer or the sequential transfer according to circumstances. As a result, it becomes possible to make the most of the functions of the image input unit, and therefore, improve efficiency of use of the image information apparatus. 
   A third example relates to a structure that makes it is possible to freely design a structure of the image information apparatus and the image reading units. The selection of the parallel transfer and the sequential transfer in the second embodiment is performed according to the structure of the image information apparatus. 
     FIG. 16  is an example of a flowchart of the operations performed by a digital multifunction product according to a third example of the present invention. These operations relate to reading image data from an original. These operations are programmed as processes (computer programs) in the scanner application  84  and the engine unit  124 . The CPU  111  sends a request to the engine unit  124  using the platform program  75  such as the SRM  86  and the ECS  95  according to the scanner application  84 . The CPU  132  in the engine unit  124  continues to execute this operation flow according to the request. 
   First, with the operation panel  120  a user instructs the multifunction product to perform simultaneous reading of both sides, and the CPU  111 , which recognizes the instruction, notifies the CPU  132  in the engine unit  124  to that effect (step S 51 ). Consequently, the CPU  132  resets a front side reading end flag (UpsideReadFlag) in the DRAM  155  (step S 52 ). 
   Subsequently, the CPU  132  judges whether the image information apparatus has a structure in which the sequential transfer is possible (step S 53 ). For example, when a storage capacity of the frame memory  135  is not enough for storing one page of the original, the CPU  132  judges that image data on both sides of the original cannot be transferred sequentially. Note that the CPU  132  obtains apparatus structure data for this judgment in advance and stores the apparatus structure data in the DRAM  155 . 
   In this way, if the image information apparatus has a structure in which the sequential transfer is possible (“Yes” at step S 53 ), the CPU  132  takes into account other conditions and selects, for example, the sequential transfer (or may select the parallel transfer depending on conditions) and sets sequential transfer flag (SeqTranceFlag) in the DRAM  155  (step S 54 ). In addition, if the image information apparatus has a structure in which the sequential transfer is impossible (“No” at step S 53 ), the CPU  132  selects the parallel transfer regardless of other conditions and resets the sequential transfer flag (step S 55 ). 
   Next, to read image data on front and back sides of an original in parallel, the CPU  132  starts a front side reading process and a back side reading process that are executed by the CPU  132  itself. The CPU  132  also starts data transfer processes for the front and the back sides shown in  FIGS. 17 and 18 . Then, in the front side reading process, when the original is conveyed to a predetermined position (“Yes” at step S 56 ), the CPU  132  starts front side reading and the DRAM controller  140  stores read image data in the frame memory  135  (step S 57 ). 
   In this way, when the reading of the front side image data and transfer of the front side image data to be described later end (“Yes” at step S 58 ), the CPU  132  ends this front side reading process. 
   On the other hand, in the back side reading process, when an original is conveyed to a predetermined reading position (“Yes” at step S 59 ), the CPU  132  starts back side reading and the DRAM controller  140  stores read image data on the back side in the frame memory  135  in parallel with the storage of the front side image data (step S 60 ). 
   In this way, when the reading of the back side image data and the transfer of the back side image data to the local memory  116  according to the back side data transfer end (“Yes” at step S 61 ), the CPU  132  judges whether a front side reading end flag, which is set by the front side data transfer process, is set. If the front side reading end flag is set, the CPU  132  confirms presence of the next original (step S 62 ). Then, if the next original is present (“Yes” at step S 62 ), the CPU  132  executes the simultaneous reading of both sides again from step S 51 . If the next original is not present, the CPU  132  ends the process directly. 
     FIG. 17  is another example of a flowchart of the operations performed by the digital multifunction product according to the third example. These operations relate to reading image data on respective sides and transferring the image data. 
   First, in the front side reading process, after starting the process, the CPU  132  starts front side reading when the original is conveyed to a predetermined reading position (step S 71 ) and the DRAM controller  140  stores read image data in the frame memory  135 . Then, when the original is read to a reading end position of the original and the reading of the front side image data ends (“Yes” at step S 72 ), the CPU  132  ends the front side reading process. 
   On the other hand, in the front side data transfer process, after starting the process, the CPU  132  waits until the condition for starting the data transfer is satisfied (step S 73 ). Note that it is assumed that the conditions for starting the data transfer are set in advance. The data transfer can be started, for example, just after the image reading process is started, or when the number of lines written in a frame memory reaches a predetermined value. 
   If the condition for staring the data transfer is satisfied (“Yes” at step S 73 ), the CPU  132  starts data transfer (step S 74 ). More specifically, the DRAM controller  140  reads out image data on the front side, which are stored in the frame memory  135 , in order from the top. The respective image data processing units  141  to  145  apply image processing to the image data. The transfer unit  151   a  sequentially captures the image data and passes the image data to the PCI transfer controller  152  for each unit of transfer. Then, the PCI transfer controller  152  transfers the image data to the local memory  116  through the PCI bus using a channel in which the DMAC  1  is set as a destination. Thereafter, the CPU  132  continues the process until the transfer of the front side data ends (step S 75 ) and, when the transfer ends (“Yes” at step S 75 ), sets a front side reading end flag (UpsideReadFlag) (step S 76 ). 
   Next, an outline of an operation flow of the back side reading process and an operation flow of the back side data transfer process will be explained with reference to  FIG. 18 . 
   First, in the back side reading process, as described above, after starting the process, the CPU  132  starts back side reading when an original is conveyed to a predetermined reading position (step S 81 ) and the DRAM controller  140  stores read image data in the frame memory  135 . Then, when the original is read to a reading end position of the original and the reading of the image data on the back side ends (“Yes” at step S 82 ), the CPU  132  ends the back side reading process. 
   On the other hand, in the back side data transfer process, after starting the process, the CPU  132  waits until the condition for starting the data transfer is satisfied (step S 83 ). Note that it is assumed that the conditions for starting the data transfer are set in advance. The data transfer can be started, for example, just after the image reading process is started, or when the number of lines written in a frame memory reaches a predetermined value. 
   If the condition for staring the data transfer is satisfied (“Yes” at step S 83 ), the CPU  132  judges whether a sequential transfer flag (SeqTranceFlag) is set (step S 84 ). If the sequential transfer flag is set, the CPU  132  waits until a front side reading end flag (UpsideReadFlag) is set (step S 84 ). On the other hand, when the sequential transfer flag is not set or the front side reading end flag is set (“No” at step S 84 ), the CPU  132  starts data transfer (step S 85 ). More specifically, the DRAM controller  140  reads out the image data on the back side stored in the frame memory  135  in order from the top, the respective image data processing unit  146  to  150  apply image processing to the image data, and the transfer unit  151   b  sequentially captures the image data and passes the image data to the PCI transfer controller  152  for each unit of transfer. Then, the PCI transfer controller  152  transfers the image data to the local memory  116  through the PCI bus using a channel in which the DMAC  2  is set as a destination. 
   Thereafter, the CPU  132  continues the process until the transfer of the back side data ends (step S 86 ) and, when the transfer ends (“Yes” at step S 86 ), ends the back side data transfer process. 
   In this way, according to the third example, it is possible not only to simply transfer image data, which are read from both sides of an original in parallel, to the secondary storage side in parallel but also to select the parallel transfer or the sequential transfer according to a structure of the image information apparatus. Thus, even when a user can establish a structure of the apparatus freely, it is possible to improve efficiency of use of the entire image information apparatus as much as possible. 
   The communication path between the image reading units and the primary storage unit has been explained to be the PCI bus and the communication control unit, which controls communication via the communication path, has been explained to be the PCI transfer controller. However, the communication path can be a USB or an IEEE1394 bus and the communication control unit can be a USB transfer controller or an IEEE1394 transfer controller. Other communication paths and communication control units can also be used as long as plural transfer data with different transmission sources and transmission destinations can be mixed in the communication paths and the communication control units. 
   According to the present invention, the image information apparatus includes the secondary storage unit that saves image data stored in the primary storage unit that temporarily stores the image data. The image information apparatus further includes the communication path, which serves as a transfer path for image data on both sides of a double-sided original, and the communication control unit, which controls communication via the communication path, between the image reading units, which are capable of reading images on the front and the back sides of the double-sided original in parallel, and the primary storage unit. The image information apparatus can pass the read image data on both the sides to the communication control unit in parallel and individually. Thus, when the image data on both the sides are transferred, the image information apparatus can transfer the image data on the one side at arbitrary timing without adjusting the timing to transfer timing of the image data on the other side. Therefore, control by the image information apparatus is simplified and queuing for adjusting the timing for transferring the image data on the one side to the transfer timing of the image data on the other side is eliminated. As a result, transfer efficiency is also improved. 
   Moreover, the communication control unit can receive transfer requests from plural transfer request sources in parallel, the communication path can transfer respective image data from the plural transfer request sources in a mixed state, and the front side data transfer process and the back side data transfer process operating in parallel, which constitute the transfer control unit, can issue transfer requests to the communication control unit independently from each other. Thus, it is possible to realize the image information apparatus according to the first aspect of the invention easily. 
   Furthermore, the communication path is the PCI bus and the communication control unit is the PCI control unit that is capable of receiving transfer requests from plural transfer request sources in parallel. Thus, it is possible to realize the image information apparatus according to the first aspect of the invention easily. 
   Moreover, the communication path is the USB bus and the communication control unit is the USB control unit that is capable of receiving transfer requests from plural transfer request sources in parallel. Thus, it is possible to realize the image information apparatus according to the first aspect of the invention easily. 
   Furthermore, the communication path is the IEEE1394 bus and the communication control unit is the IEEE1394 control unit that is capable of receiving transfer requests from plural transfer request sources in parallel. Thus, it is possible to realize the image information apparatus according to the first aspect of the invention. 
   Moreover, when image data on both sides of an original are sent to the primary storage unit, it is possible to transfer the image data on both the sides in parallel or transfer the image data in time series. This makes it possible to perform parallel transfer and time series transfer according to circumstances. Therefore, it is possible to make the most of functions of the image input unit and improve efficiency of use of the entire image information apparatus. 
   Furthermore, it is possible to select whether image data on both sides of an original is to be transferred in parallel or transferred in time series according to a structure of the image information apparatus. Thus, it is possible to improve efficiency of use of the entire image information apparatus as much as possible even when a user can establish a structure of an apparatus freely. 
   Moreover, when the image reading units cannot transfer image data on both sides of an original sequentially, the selecting unit selects an operation for always transferring the image data on both the sides in parallel. Thus, even if the image reading units cannot transfer the image data on both the sides sequentially, it is possible to process the transfer of the image data without deficiency. 
   Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.