JP5001223B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus having a one-pass double-sided simultaneous reading mechanism that reads a document image on the front and back sides of a document with a single sheet passing, and a local memory that stores the read image data.

  In recent years, scanners and digital multi-function peripherals having a mechanism for simultaneously reading the front and back of a double-sided original (one-pass double-sided simultaneous reading mechanism) with a single sheet passing through the original reading unit have been commercialized. These products aim to improve the productivity of reading double-sided originals by reading both sides simultaneously, reduce the load damage to the originals by reading both sides in one pass without inverting the original, and reduce noise by one pass. is there.

  In such a scanner or digital multi-function peripheral having a one-pass double-sided simultaneous reading mechanism, the reading time can be shortened since reading for two sides can be performed with the reading time for one side, but image data for two sides is reduced. To send to the output device, double the image processing unit on the input device side, double the data transfer capacity between the input device and the output device, sufficient bandwidth of the bus, CPU (central processing unit) on the output device side In order to satisfy these requirements, there is a problem that the total cost increases significantly.

To solve this problem, a configuration has been proposed in which an inexpensive local memory is arranged on the input device side, and the scanned images for the two surfaces are temporarily stored in the local memory, sequentially processed one by one, and transferred to the output device. Has been. By adopting such a configuration, it is possible to improve the reading productivity of double-sided originals while reducing the total cost.
JP-A-6-103225 JP 2000-158724 A

  However, in the case of one-pass duplex reading using the one-pass duplex reading mechanism, the reading sensor (CCD line image sensor, etc.) of the reading unit is physically different for the front side and the back side. Etc. are different from the front and back. In order to solve this problem, it is necessary to adjust the image quality of the front and back, and it is necessary to switch the parameters for adjusting the image quality alternately on the front and back. In recent years, opportunities for color originals have increased, and the amount of parameters for image quality adjustment for color image signals has become enormous.

  However, in the configuration of the input 2-pass output 1-pass using the local memory described above, the image processing unit and the image transfer unit process only one side at a time while reading the two sides of the front and back sides of the document simultaneously. Since this is not possible, there is a problem that in the pass after output from the local memory, the processing time between images becomes overhead due to frequent parameter switching on the front and back sides, and a huge amount of parameters, leading to the improvement in productivity.

  In order to deal with these problems, the present invention provides means by continuously processing the same surface of the front surface or the back surface.

  The present invention has been made in view of such circumstances, and an image that can reduce the number of parameter switchings that occur in the case of one-pass duplex reading using a one-pass duplex reading mechanism and minimize overhead. An object is to provide a reader.

The present invention is an image reading apparatus having a one-pass double-sided simultaneous reading mechanism for reading original images on the front and back sides of a document with a single sheet passing, and a local memory for storing the read image data. Image data processing means for simultaneously reading both front and back images using a simultaneous reading mechanism, storing the read image data in a local memory, taking out the stored image data, and performing image processing and image output; When the image data processing means sequentially performs processing for each surface, it reads a plurality of continuous sheets, stores the image data obtained thereby in the local memory, takes out the image data from the local memory, performs image processing and when the image output, by treating the surface or back surface of continuous successive one frame, further, the image data processing means, The capacity and the original size of Karumemori, in which so as to determine the number of documents in the best frame.

  Further, the reading operation is stopped when image processing or transfer is not in time.

  Also, a warning is urged when the reading operation is stopped when image processing or transfer is not in time.

  In addition, the reading operation is stopped when the image processing or the transfer is not in time, and the reading operation is resumed when the image processing or the transfer for the image data stored in the local memory is completed. .

In addition, the distance between the document in the frame is controlled.

Also, the number of documents in the determined frame and the image data size are compared with the image processing speed and the image transfer speed.

In addition, an optimum frame interval is selected for the number of documents in the determined frame.

The user can select whether or not to perform frame reading control.

  Therefore, according to the present invention, since the front and back surfaces of a plurality of documents to be continuously read are processed as the same frame data, this occurs in the case of one-pass duplex reading using the one-pass duplex reading mechanism. The effect of reducing the number of times of parameter switching and minimizing the overhead is obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an example of a schematic configuration of a compound machine according to an embodiment of the present invention. Here, an image forming apparatus in which the functions of each apparatus such as a printer, a copy, a facsimile, and a scanner are housed in one casing is hereinafter referred to as a multi-function apparatus.

  First, the reading process of the reading unit 1 and the image forming process of the image forming unit 2 will be briefly described with reference to FIG. FIG. 2 is a view of the document table 1a as viewed from above. FIG. 1 shows a configuration that does not include a one-pass double-sided simultaneous reading mechanism. The specific configuration of the one-pass double-sided simultaneous reading mechanism is well known and will not be described.

  The document PP is scanned and exposed by an exposure lamp 1b movable along the document table 1a, and the reflected light is subjected to photoelectric conversion by a CCD (image sensor) 1c to obtain an electrical signal corresponding to the intensity of the light.

  An IPU (image processing unit) 1d performs processing such as shading correction on the electrical signal to perform A / D conversion to obtain an 8-bit digital signal, and further performs image processing such as scaling and dithering to generate an image synchronization signal. At the same time, an image signal is sent to the image forming unit 2.

  In order to execute the above process, the scanner control unit 1e performs detection of various sensors, control of a drive motor, and the like, and sets various parameters in the IPU 1d. The above is the reading process.

  In the image forming unit 2, the constant rotating photoconductor 1b uniformly charged by the charging charger 2a is exposed by a laser beam modulated by image data from the writing unit 2c. An electrostatic latent image is formed on the photoconductor 2b, and a developed toner image is developed by developing the toner with toner using the developing device 2d.

  The transfer paper that has been fed and conveyed from the paper feed tray 2f by the paper feed roller 2e in advance and is waiting by the registration roller 2g is conveyed in time with the photoconductor 2b, and the toner on the photoconductor 2b is transferred by the transfer charger 2h. Electrostatic transfer is performed on the paper, and the transfer paper is separated from the photoreceptor 2b by the separation charger 2i. Thereafter, the toner image on the transfer paper is heated and fixed by the fixing device 2j, and is discharged onto the discharge tray 2l by the discharge roller 2k.

  On the other hand, the toner image remaining on the photosensitive member 2b after electrostatic transfer is removed by the cleaning device 2m being pressed against the photosensitive member 2b, and the photosensitive member 2b is discharged by the discharging charger 2n. The plotter control unit 2p performs detection of various sensors and control of a drive motor and the like in order to execute the above process. The above is the image forming process.

  Here, the state of the image synchronization signal output from the IPU 1d of the reading unit 1 will be described with reference to FIGS.

  The frame gate signal / FGATE is a signal representing the effective image range for the image area in the sub-scanning direction, and image data during which this signal is at a low level (low active) is valid. The frame gate signal / FGATE is asserted or negated at the falling edge of the line synchronization signal / LSYNC.

  The line synchronization signal / LSYNC is asserted for a predetermined number of clocks at the rising edge of the pixel synchronization signal PCLK, and image data in the main scanning direction is validated after a predetermined clock after the rising of this signal. The transmitted image data is one for one period of the pixel synchronization signal PCLK, and is divided into 400 DPI (dot per inch) equivalent from the arrow portion in FIG. The image data is sent out as raster format data starting from the arrow. Further, the sub-scanning effective range of image data is usually determined by the transfer paper size.

  Returning to FIG. 1, the system control unit 3 detects an input state to the operation unit 4 by the operator, and various parameters to the reading unit 1, the storage unit 5, the image forming unit 2, the FAX unit 6, and the I / F unit 7. Settings, process execution instructions, etc. are performed via communication. The state of the entire system (including a warning light for the user) is displayed on the operation unit 4. An instruction to the system control unit 3 is made by key input to the operation unit 4 by the operator.

  In response to an instruction from the system control unit 3, the FAX unit 6 performs binary compression on the received image data based on the G3 / G4 FAX data transfer rules and transfers the image data to the telephone line. The data transferred from the telephone line to the FAX unit is restored to binary image data, which is sent to the writing unit of the image forming unit 2 to be visualized.

  The I / F unit 7 transmits data in the storage unit 5 to the outside or receives it from the outside and stores it in the storage unit 5 with support from the system control unit 3. The command selector unit 8 changes the selection state according to an instruction from the system control unit 3, and sets the source of image data for image formation as the reading unit 1, the storage unit 5, the FAX unit 6, and the I / F unit 7. Select from either.

  The storage unit 5 normally stores image data of a document input from the IPU 1d, and is used for a copy application such as repeat copy or rotation copy. Further, it is also used as a buffer memory for temporarily storing binary image data from the FAX unit 6. Further, it is used as means for storing unique information of the input / output device means. These data storage instructions are given by the system control unit 3.

  FIG. 4 shows a configuration example of the storage unit 5.

  In the figure, an image input / output DMAC 5a is composed of a CPU and a logic, communicates with the memory control unit 5c, receives a command, performs operation settings according to the command, and changes the state of the image input / output DMAC 5a. It is sent as status information for notification.

  When an image input command is received, the input image data is packed as memory data in units of 8 pixels according to the input image synchronization signal, and is output to the memory control unit 5c together with the memory access signal as needed. When an image output command is received, the image data from the memory control unit 5c is output in synchronization with the output image synchronization signal.

  The image memory 5b stores image data, and is composed of a semiconductor storage element such as a DRAM. The total amount of memory is 400 DPI, 4 Mbytes of A3 size of binary image data, and 4 Mbytes of memory for storing electronic sorts. The data transfer work area 6 MB and the image data management area 2 MB are 16 MB in total. Reading and writing are controlled from the memory control unit 5c.

  The memory control unit 5c is composed of a CPU and logic, communicates with the system control unit 3, receives a command, performs operation settings according to the command, and also serves as status information to inform the state of the storage unit 5. Send.

  The operation commands from the system control unit 3 include image input, image output, compression, decompression and the like. Image input and image output commands are input to the image input / output DMAC 5a, and compression-related commands are image transfer DMAC 5d and code transfer DMAC 5e. Are transmitted to the compression / decompression unit 5f.

  Here, FIG. 5 shows the configuration of the address generation unit and the comparison unit of the memory control unit 5c, and the function of the memory control unit 5c will be described for each block.

  The input / output image address counter 5ca is an address counter that counts up in response to an input / output memory access request signal, and outputs a 22-bit memory address indicating a storage location where the input / output image data is stored. The address is initialized once at the start of memory access.

  The transfer image address counter 5cb is an address counter that counts up in response to a transfer memory access permission signal, and outputs a 22-bit memory address indicating a storage location where transfer image data is stored. The address is initialized once at the start of memory access.

  When the semiconductor memory is used as a buffer at the time of image input, the line setting unit 5cc compares a value to be compared with the difference result between the input processing line and the transfer line output from the difference calculation unit 5cd by the difference comparison unit 5ce. Set from 3. An arbitrary value can be set.

  When inputting an image, the difference calculation unit 5cd subtracts the number of input / output processing lines output from the image input / output unit DMAC 5a from the number of transfer processing lines output from the compression / decompression unit 5f, and outputs the result to the difference comparison unit 5ce.

  The difference comparison unit 5ce compares the number of difference lines output from the difference calculation unit 5cd with the set value output from the line setting unit 5cc at the time of image input, and if the difference line number equals the set value, an error signal is output. If the difference line number becomes 0, the transfer request mask signal of the comparison result output to the arbiter is made active. Otherwise, active is not output in the state where the input / output image is not in operation.

  The address selector 5cf is a selector selected by the arbiter 5cg, and selects either the input image or the transfer image address.

  The arbiter 5cg outputs a memory access permission signal for accessing the compression / decompression unit. A memory access permission signal is output under the condition that the address comparison signal is active and the input / output memory access signal is inactive.

  The request mask unit 5ch masks the transfer memory access request signal for accessing the compression / decompression unit 5f based on the comparison result from the difference comparison unit 5ce, and stops the transfer process.

  The access control circuit 5ci divides the input physical address into a row address / column address corresponding to a DRAM which is a semiconductor memory, and outputs it to an 11-bit address bus. Further, in accordance with an access start signal from the arbiter 5cg, a DRAM control signal (RAS, CAS, WE) is output.

  In response to an image input instruction from the system control unit 3, the memory control unit 5 c is initialized and enters a standby state for image data, and the image data is input to the storage unit 5 when the reading unit 1 operates. The input image data is once written in the semiconductor memory. The number of processing lines of the written image data is counted by the image input / output DMAC 5a and input to the memory control unit 5c.

  The compressor / decompressor 5f receives the image transfer command and outputs a transfer memory access request signal. However, the request signal is masked by the request mask unit 5ch of the memory control unit 5c, and actual memory access is not performed. . When one line of input data from the image input / output DMAC 5a is completed, the mask of the transfer memory access request signal is released, the semiconductor memory is read, and the transfer operation of the image data to the compression / decompression device 5f is started. . Further, even during operation, the difference calculation unit 5cd calculates the difference between the two processing lines, and when it becomes 0, the transfer memory access request signal is masked so that the address is not overtaken.

  The above is the description of the configuration of the memory control unit 5c.

  The image transfer DMAC 5d is composed of a CPU and logic, communicates with the memory control unit 5c, receives a command, performs operation settings according to the command, and transmits it as status information to inform the state. When a compression command is received, a memory access request signal is output to the memory control unit 5c. When the memory access permission signal is active, image data is received and transferred to the compression / decompression unit. In addition, an address counter that counts up in response to a memory access request signal is built in, and a 22-bit memory address indicating a storage location where image data is stored is output.

  The code transfer DMAC 5e is composed of a CPU and logic, communicates with the memory control unit 5c, receives a command, performs operation settings according to the command, and transmits it as status information to inform the state. When a decompression command is received, a memory access request signal is output to the memory control unit 5c. When the memory access permission signal is active, image data is received and transferred to the compression / decompression unit 5f. In addition, an address counter that counts up in response to a memory access request signal is built in, and a 22-bit memory address indicating a storage location where image data is stored is output. The descriptor access operation of the DMAC will be described later.

  The compression / decompression unit 5f includes a CPU and logic, communicates with the memory control unit 5c, receives a command, performs operation settings according to the command, and transmits it as status information to notify the state. . Binary data is processed by the MH encoding method.

  The magnetic disk drive (HDD) controller 5g is composed of a CPU and logic, communicates with the memory control unit, receives commands, performs operation settings according to the commands, and status information for informing the state. Send as. Reads the status of the magnetic disk device 5h and transfers data. The magnetic disk device 5h constitutes a secondary storage device.

  The above is the description of the configuration of the storage unit 5.

  As the overall operation of the storage unit 5, image data is written to or read from a predetermined image area of the image memory 5b by an image transfer DMAC 5d according to an instruction from the system control unit 3 when inputting an image and storing data. . At this time, the image transfer DMAC 5d counts the number of image lines.

  FIG. 6 is a block diagram for explaining the software configuration of the compound machine. The multi-function apparatus 1S is configured to include a software group 2S, a multi-function apparatus starting unit 3S, and a hardware resource 4S.

  The MFP starter 3S is executed first when the MFP 1S is powered on, and starts the application layer 5S and the platform 6S. For example, the multi-function apparatus activation unit 3S reads the programs of the application layer 5S and the platform 6S from a hard disk device (hereinafter referred to as HDD) corresponding to the external storage unit, transfers the read programs to the memory area, and activates them. . The hardware resource 4S includes a monochrome laser printer (B & W LP) 11S, a color laser printer (Color LP) 12S, and a hardware resource 13S such as a scanner or a facsimile.

  The software group 2S includes an application layer 5S and a platform 6S activated on an operating system (hereinafter referred to as OS) such as UNIX (registered trademark). The application layer 5S includes a program for performing processing unique to each user service related to image formation such as a printer, a copy, a fax, and a scanner.

  The application layer 5S includes a printer application 21S that is a printer application, a copy application 22S that is a copy application, a fax application 23S that is a fax application, and a scanner application 24S that is a scanner application.

  Further, the platform 6S interprets a processing request from the application layer 5S and generates a hardware resource 4S acquisition request, and manages one or more hardware resources 4S to control the control service layer 9S. A system resource manager (hereinafter referred to as SRM) 39S that arbitrates acquisition requests from the SRM 39 and a handler layer 10S that manages hardware resources 4S in response to acquisition requests from the SRM 39S.

  The control service layer 9S includes a network control service (hereinafter referred to as NCS) 31S, a delivery control service (hereinafter referred to as DCS) 32S, an operation panel control service (hereinafter referred to as OCS) 33S, and a fax control service (hereinafter referred to as FCS) 34S. , One or more engine control service (hereinafter referred to as ECS) 35S, memory control service (hereinafter referred to as MCS) 36S, user information control service (hereinafter referred to as UCS) 37S, system control service (hereinafter referred to as SCS) 38S The service module is configured to be included.

  The platform 6S is configured to have an API 53S that can receive a processing request from the application layer 5S using a predefined function. The OS executes the software of the application layer 5S and the platform 6S in parallel as processes.

  The NCS 31S process provides a service that can be commonly used for applications that require network I / O. Data received from each network according to each protocol is distributed to each application, and data from each application Mediation when sending to the network side.

  For example, the NCS 31S controls data communication with a network device connected via a network using HTTP (HyperText Transfer Protocol) by HTTP (HyperText Transfer Protocol Daemon).

  The DCS 32S process performs control such as distribution of stored documents. The process of the OCS 33S controls an operation panel serving as information transmission means between the operator and the main body control. The FCS34S process provides APIs to perform fax transmission and reception using the PSTN or ISDN network from the application layer 5S, registration / quotation of various fax data managed in the backup memory, fax reading, fax reception printing, etc. To do.

  The ECS 35S process controls engine units such as the black and white laser printer 11S, the color laser printer 12S, and the hardware resource 13S. The process of the MCS 36S performs memory control such as acquisition and release of memory and use of the HDD. The UCS 37S manages user information.

  The process of the SCS 38S performs processing such as application management, operation unit control, system screen display, LED display, hardware resource management, and interrupt application control.

  The process of the SRM 39S controls the system and manages the hardware resource 4S together with the SCS 38S. For example, the process of the SRM 39S mediates and controls execution according to an acquisition request from an upper layer using the hardware resource 4S such as the black and white laser printer 11S and the color laser printer 12S.

  Specifically, the process of the SRM 39S determines whether or not the requested hardware resource 4S is available (whether it is not used by another acquisition request). The upper layer is notified that the resource 4S is available. Further, the process of the SRM 39S performs scheduling for using the hardware resource 4S in response to an acquisition request from an upper layer, and the request contents (for example, paper conveyance and image forming operation by the printer engine, memory allocation, file generation, etc.) Has been implemented directly.

  The handler layer 10S includes a fax control unit handler (hereinafter referred to as FCUH) 40S for managing a fax control unit (hereinafter referred to as FCU), which will be described later, and an image for allocating memory to the process and managing the memory allocated to the process. And a memory handler (hereinafter referred to as IMH) 41S. The SRM 39S and the FCUH 40S make a processing request for the hardware resource 4S by using the engine I / F 54 that can transmit a processing request for the hardware resource 4S by a predefined function.

  The multi-function apparatus 1S can centrally process processes commonly required for each application on the platform 6S. Next, the hardware configuration of the multifunction machine 1S will be described.

  FIG. 7 shows a hardware configuration diagram of an embodiment of the multi-function apparatus 1S according to the present invention. The multi-function apparatus 1S includes a controller 60, an operation panel 70, an FCU 80, a USB device 90, an IEEE 1394 device 100, and an engine unit 120.

  The controller 60 includes a CPU 61, a system memory (MEM-P) 62, a north bridge (hereinafter referred to as NB) 63, a south bridge (hereinafter referred to as SB) 64, an ASIC 66, and a local memory (MEM-C). ) 67 and HDD 68.

  The operation panel 70 is connected to the ASIC 66 of the controller 60. Further, the MLC 43, FCU 80, USB device 90, IEEE 1394 device 100, and engine unit 120 are connected to the ASIC 66 of the controller 60 via a PCI bus.

  In the controller 60, the local memory 67, the HDD 68, and the like are connected to the ASIC 66, and the CPU 61 and the ASIC 66 are connected via the NB 63 of the CPU chip set. In this way, if the CPU 61 and the ASIC 66 are connected via the NB 63, it is possible to cope with a case where the interface of the CPU 61 is not disclosed.

  The ASIC 66 and the NB 63 are not connected via the PCI bus, but are connected via an AGP (Accelerated Graphics Port) 65. Thus, in order to control the execution of one or more processes forming the application layer 5S and the platform 6S in FIG. 6, the ASIC 66 and the NB 63 are connected via the AGP 65 instead of the low-speed PCI bus to prevent performance degradation. It is out.

  The CPU 61 performs overall control of the compound machine 1S. The CPU 61 starts and executes NCS 31S, DCS 32S, OCS 33S, FCS 34S, ECS 35S, MCS 36S, UCS 37S, SCS 38S, SRM 39S, FCUH 40S, and IMH 41S as processes on the OS, and also forms a printer application 21S that forms an application layer 5S, a copy application 22S, fax application 23S, and scanner application 24S are activated and executed.

  The NB 63 is a bridge for connecting the CPU 61, the system memory 62, the SB 64, and the ASIC 66. The system memory 62 is a memory used as a drawing memory or the like of the multifunction machine 1S. The SB 64 is a bridge for connecting the NB 63 to the ROM, PCI bus, and peripheral device. The local memory 67 is a memory used as a copy image buffer and a code buffer.

  The ASIC 66 is an IC for use in image processing having hardware elements for image processing. The HDD 68 is a storage for storing image data, document data, programs, font data, forms, and the like. The operation panel 70 is an operation unit that accepts an input operation from an operator and performs display for the operator.

  The ASIC 66 has a DMA controller function for transferring images, and is connected to the scanner and plotter of the engine unit 120 through the PCI bus as shown in FIG.

  Further, as shown in the figure, the ASIC 66 has two channels of video input DMA controllers and a video output DMA controller, which are assigned different PCI bus addresses, scanner input 1, scanner input 2, and plotter output. The video data can be transferred in parallel.

  Here, the front side read image data output from an image reading unit (not shown) provided with a one-pass double-sided simultaneous reading mechanism is the scanner input 1, and the back side read image data is the scanner input 2.

  When the images read by the image reading unit are transferred to the MEM-C67 simultaneously on both sides, the IMH 41S secures the memory for the transfer image size in the MEM-C67 in response to the process request from the SRM 39S, and the transfer image sizes Xw, Yw Transfer is possible by setting the reserved memory address in the video input DMA controller.

  FIG. 9 is a functional block diagram of the engine unit showing an example of realizing simultaneous reading of the front and back sides of a double-sided document.

  The image data control IF controller 2B is directly controlled by the CPU 1B.

  There are image input means 3B and 4B for inputting two types of image data of front side read image data and back side read image data output from an image reading unit equipped with a one-pass double-sided simultaneous reading mechanism. It has a frame memory 5B such as DRAM for storing, and has one or more output means 6B such as GAVD (image signal processing means).

  It is connected to a data bus such as a PCI, and can output data from an external storage device while inputting data to the external storage device.

  This is used to adjust the input timing on the front and back sides and the data transfer rate to the PCI bus when reading both sides simultaneously.

  In this embodiment, it is assumed that the input image writing to the frame memory 5B and the input image reading from the frame memory 5B can be performed in parallel, and when performing double-sided reading, the front image to the frame memory 5B. The writing of the image and the writing of the back image can be executed in parallel.

  A signal flow when reading a document will be described based on this functional block diagram.

The document reading operation is divided into the following two operations.
(1) The image signal input by the document reading unit is written in the frame memory.
(2) The image signal stored in the frame memory is read and transferred to the storage device via the data bus.

  First, the operation (1) will be described by taking the surface reading as an example.

  The image signal input from the image input means 3B for inputting the surface read image data is input to the image data control IF 2B via the shading function block 7B. Data received by the image data control IF 2B is transferred to the frame memory 5B side by the selector B 26 via the DRAM controller B3. In the frame memory 5B, input data is sequentially written and stored.

  Next, the operation (2) will be described.

  Data stored in the frame memory 5B is transferred to the PCI transfer controller 27B by the selector B26 via various image signal processing function blocks. The transferred data is stored in a storage device (not shown) via the data bus (PCI_Bus) by the PCI transfer controller B27.

  As the image signal processing functional blocks, there are a mask B4, a filter B5, a scaling B6, an area expansion / reduction B7, an image compression B8, a blank sheet detection B9, and the like.

  The selector B26 includes a plurality of image input units and a plurality of image output units, and has a function of switching image data for outputting input image data to an arbitrary image output unit.

  The PCI transfer controller B27 has a function of outputting a plurality of image data output from the selector B26 to the storage device. It is possible to set a data capacity and an image data transfer speed necessary for outputting each image data to the storage device.

  A procedure for performing double-sided simultaneous reading with the above configuration will be described.

(Description of overall flow)
A control sequence for simultaneous reading on both sides will be described.

  First, double-sided simultaneous reading is set.

  In order to process the front and back simultaneously in parallel, the front side reading process and the back side reading process are started.

  Start transporting the document. Here, in the configuration of this embodiment, it is assumed that the reading operation of the next original is continued if the reading of the previous original is completed and the next original exists at that time. If there is no next original, the transport operation is terminated after the final original is discharged.

  In the surface reading process, frame reading of the surface is started and waits until reading of one frame is completed. Further, in the back side reading process, frame reading on the back side is started and waits until reading of one frame is completed.

  Wait for completion of reading the front and back frames and check the next document.

  If the next original exists, the next frame reading is started in both the front side reading process and the back side reading process.

  If there is no next original, the reading operation is terminated.

(Explanation of table reading flow)
Next, a control sequence at the time of reading the front frame will be described. Here, the number of documents in the frame is N.

  First, in order to execute document reading (input from the image input unit 3B to the frame memory 5B) and image processing and image transfer (output from the frame memory 5B to the PCI bus) in parallel, the surface image input process and the surface Start the image output process.

(Explanation of table input procedure)
The surface image input process will be described.

  First, the front frame internal document counter is reset.

  In the surface image input process, when the original arrives at a predetermined reading position, the surface reading is started. The input data from the image input means 3B is accumulated from the top address of the surface area in the frame memory 5B. Thereafter, the process waits until the document arrives at the prescribed image reading end position.

  When the original reaches the reading end position, the in-frame original counter is incremented.

  Check for the presence of the next manuscript. If there is a next original and the in-frame original counter is less than N, reading of the next original is started. Wait for the document to reach the reading position.

  When the original arrives at the prescribed reading position, the front side reading is started in the same manner as before.

  The input data from the image input means 3B is accumulated from the address of the final position + 1 of the preceding image data. Thereafter, the same operation is repeated for the number of documents in the frame.

  If there is no next document or the in-frame document counter is N, the front image input process is terminated, assuming that one frame has been read.

(Explanation of table output procedure)
Next, the surface image output process will be described.

  In the surface image output process, image processing parameters such as surface processing and image quality for the surface, and image transfer settings are immediately set. After setting, wait until the condition for starting the surface image output is satisfied.

  If the condition for starting the surface image output is satisfied, image processing and image transfer are started.

  Thereafter, the process waits until the image transfer of the final input data is completed.

  When the image transfer is finished, the surface image output process is finished.

(Description of back reading flow)
Next, a control sequence at the time of reading the back frame will be described.

  First, in order to execute document reading (input from the image input unit 4B to the frame memory 5B), image processing and image transfer (output from the frame memory 5B to the PCI bus) in parallel, the back side image input process and the back side image are performed. Start the output process.

(Description of back entry procedure)
First, the back side image input process will be described.

  Reset the document counter in the back frame.

  In the back side image input process, the back side scanning is started when the document arrives at a predetermined reading position. The input data from the image input means 4B is accumulated from the top address of the back area in the frame memory 5B. Thereafter, the process waits until the document arrives at the prescribed image reading end position. When the original reaches the reading end position, the in-frame original counter is incremented.

  Check for the presence of the next manuscript.

  When there is a next original and the in-frame original counter is less than N, reading of the next original is started. Wait for the document to reach the reading position.

  When the original arrives at the prescribed reading position, the back side scanning is started as before.

  Input data from the image input means 4B is accumulated from the address of the final position + 1 of the preceding image data.

  Thereafter, the same operation is repeated for the number of documents in the frame.

  If the next original does not exist or the in-frame original counter is N, it is determined that reading of one frame has ended, and the back side image input process is ended.

(Description of back output procedure)
The backside image output process will be described.

  In the back side image output process, the process waits until the back side image output start condition is satisfied. Here, the end of the front surface image output process is set as a start condition.

  If the conditions for starting the back image output are satisfied, the image processing parameters such as the spatial processing and image quality for the back surface, and the image transfer are immediately set. Start image processing and image transfer.

After setting, wait until the condition for starting the surface image output is satisfied.
Then, image processing and image transfer are started.

  Thereafter, the process waits until the image transfer of the final input data is completed.

  As described above, in the case of a reading device having a two-pass input and one-pass output configuration using a local memory, for example, when N double-sided originals are processed when the number of originals in a frame is N, conventional double-sided simultaneous In reading, the number of reading surface (N × 2 times) parameter switches are performed. However, the apparatus of this embodiment can be realized with two parameter switches regardless of N. As a result, frequent parameter switches are not required, and it can be expected that the productivity of simultaneous reading on both sides is improved.

  Here, in the above description, when the number N of documents in the frame is designated, the total amount FMem of the image data in one frame is calculated from the document size S and various reading conditions (such as variable magnification and color mode).

  Then, the capacity SLMMem that can be used for one frame of the local memory is compared with the memory amount MemF in one frame, and when the SLMMem is smaller, a warning display and stop processing are performed.

  Therefore, it is predicted that the local memory will overflow with the size of the document to be read and the designated number of documents in the frame, and it is possible to prevent malfunction by stopping the warning and reading operation in advance by the user.

  Also, the maximum number Nmax of documents in a frame is calculated from the capacity SLMMe that can be used for one frame of the local memory based on the document size S and various reading conditions (magnification and color mode, etc.).

  By doing so, the optimum number of documents in the frame can be determined according to the capacity of the local memory and the size of the document to be read. It can be expected to operate with the highest productivity in simultaneous reading on both sides.

  Also, if for some reason the image data input to the local memory overtakes the image data output (the next data is written to the local memory area where the pre-output data is saved), warning display and stop processing I do.

  Specifically, the write address and read address of the local memory and the input speed to the local memory are monitored, and when it is predicted that the write address will overtake the read address, the conveyance of the document is temporarily stopped.

  Then, when the document conveyance is stopped, the image data stored in the local memory is subjected to image processing and image transfer, and after the image transfer is completed, the reading operation is resumed.

  In this way, when processing delays occur due to any cause, it is possible to prevent malfunctions by stopping the warning and reading operations, and restarting document reading after the problem has been resolved, so that re-execution operations can be performed. A simple image reading apparatus which is not bothered can be provided.

  Also, the input speed to the local memory, the time required for image processing and image transfer, and the like are measured in advance, and the processing capability in the processing system is grasped and stored. For example, the optimum frame interval in the processing system is determined based on the document size S and various reading conditions (such as variable magnification and color mode). Then, the user can designate whether or not to perform these controls.

  In this way, when the image processing and image transfer capabilities are inferior to the image input speed, it is possible to prevent malfunctions by controlling the document interval between frames and delaying the input speed. By controlling at an optimal frame interval based on the above, it is possible to provide an image reading apparatus with high productivity and reliability in simultaneous reading on both sides.

  Further, it is possible to provide an image reading device that can be used even when the output device does not have the function required by the input device (change of image order).

The schematic block diagram which showed an example of schematic structure of the compound machine concerning one Example of this invention. Schematic showing how the document table is seen from above. 4 is a waveform diagram illustrating an example of an image synchronization signal output from the IPU 1d of the reading unit 1. FIG. FIG. 3 is a block diagram showing a configuration example of a storage unit 5. The block diagram which showed the structure of the address generation part of the memory control part 5c, and a comparison part. The block diagram for demonstrating the software structure of a multi-functional machine. Block diagram for explaining the hardware configuration of the compound machine FIG. 3 is a schematic block diagram for explaining a configuration when reading image data output from an image reading unit (not shown) including a one-pass duplex reading mechanism is stored in a memory or read out. The functional block diagram of the engine part which shows the example which implement | achieves the simultaneous reading of the surface of a double-sided document, and a back surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reading part 3 System control part 5 Memory | storage part 5c Memory control part 5b Image memory

Claims (8)

An image reading apparatus having a one-pass double-sided simultaneous reading mechanism for reading a document image on the front and back sides of a document by one sheet passing, and a local memory for storing the read image data,
Image data processing means for simultaneously reading both the front and back images using the one-pass duplex reading mechanism, storing the read image data in a local memory, taking out the stored image data, and performing image processing and image output With
When the image data processing means sequentially performs processing for each surface, the image data processing unit reads a plurality of continuous images, accumulates image data obtained thereby, and extracts the image data from the local memory to perform image processing. And when outputting an image, the continuous front surface or continuous back surface is processed as one frame ,
further,
The image data processing unit determines an optimum number of documents in a frame based on a capacity of a local memory and a document size. The image reading apparatus according to claim 1, characterized in that to stop the reading operation in the image processing and the transfer is not in time. 3. The image reading apparatus according to claim 2 , wherein a warning is urged when the reading operation is stopped when image processing or transfer is not in time. Stop operation readings when the image processing and the transfer is not in time, After completion the image processing and the transfer of the image data stored in the local memory, according to claim 3, characterized in that to resume the reading operation The image reading apparatus described. Image of the mounting serial to any one of claims 1 to 4, characterized in that to control the spacing of the document and the document in the frame reader. Number of documents and the image data size and the image processing speed of the determined frame, the image reading apparatus according to claim 5, wherein comparing the image transfer speed. The image reading apparatus according to claim 6 , wherein an optimal frame interval is selected for the number of documents in the determined frame. 8. The image reading apparatus according to claim 7 , wherein the user can select whether to perform frame reading control.