JP2005159705A - Image formation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image formation system that suppresses a decrease in the productivity of printing processing by reducing an occupation quantity of a memory in a slave, and reduces an occupation quantity of traffic on a network. <P>SOLUTION: A compression section 411 creates compressed image data from original image data (step S22). A compression selector 412 compares the size of the original image data with that of the compressed image data (step S23), selects the compressed image data as data to be transmitted when a size of compressed data is smaller than that of the original image data (step S24), and selects the original image data as data to be transmitted when the size of the compressed data is larger than or is the same as that of the original image data (step S25). An expander 413 successively expands the compressed image data (step S31). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming system that performs printing simultaneously from a plurality of image forming apparatuses connected via a network.

  In an image forming system in which a plurality of image forming apparatuses are connected via a network, a certain image forming apparatus (master) scans an image with a scanner, for example, and stores the obtained image data in a memory for printing. In addition, there is a technique called so-called linked copy or linked print that improves printing productivity by transferring to other image forming apparatuses (slave) and storing the image data in the slave memory for printing. .

  In an image forming apparatus represented by an MFP (Multi Function Peripheral) that operates a plurality of image processing processes, in recent years, the size of image data to be handled has increased with the increase in color, resolution, and quality of image data. ing. When image data with a large data size is handled in this way, a large amount of master and slave memory is consumed and free memory is reduced, so that productivity of each image processing process such as scan processing, print processing, and image conversion processing is increased. descend.

  In Patent Document 1, when there is no more space in a memory of a certain slave, the master interrupts transmission of image data to the slave, deletes the transmitted image data, and prints on another image forming apparatus. A method is described in which image data that has already been transmitted is printed and the transmission of the image data is resumed after the memory becomes empty. In this case, since the master cannot transmit image data until the slave memory becomes empty, productivity of the entire printing process is lowered. When data is retransmitted to another slave, the image data flowing through the network increases accordingly.

  When the master and the slave are connected on a one-to-one basis, even if a large amount of image data is sent to the network, it does not affect other devices. On the other hand, when a master and a slave are connected to various other devices via a network, image data can be sent using the network bandwidth significantly by linked copy operation. Reduce the performance of the action you perform.

JP 2000-261595 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming system in which the amount of slave memory is reduced to suppress a decrease in productivity of print processing and the amount of traffic on the network is reduced.

  An image forming system according to the present invention includes a plurality of image forming apparatuses connected via a network and transferring image data from any one of the image forming apparatuses to at least one other image forming apparatus. The forming apparatus includes a compression unit, a comparison selection unit, and an expansion unit. The compression unit compresses image data to be transferred. The comparison / selection unit compares the size of the image data before compression with the size of the image data after compression, and if the size of the image data after compression is smaller than the size of the image data before compression, the image data after compression is selected. If the size of the image data after compression is larger than or the same as the size of the image data before compression, the image data before compression is selected as the image data to be transferred. The decompressing unit decompresses the received compressed image data.

  Further, the comparison / selection unit provided in the image forming system of the present invention compares the size of the image data before compression with the size of the image data before compression by comparing the size of the image data before compression with a coefficient larger than 0 and less than 1 If the size of the image data after compression is smaller than the size obtained by multiplying the image data by a coefficient, select the image data to which the compressed image data is transferred, and select the image after compression by the size obtained by multiplying the image data before compression by the coefficient. If the data size is large or the same, the image data before compression may be selected as the image data to be transferred. Further, the user may set a coefficient.

  Further, it is preferable that the printing operation is performed by both the transfer source image forming apparatus and the transfer destination image forming apparatus.

  The image forming method of the present invention prints image data formed or read image data in any one of a plurality of image forming apparatuses connected via a network, compresses the image data, and compresses the image data. Compare the size of the previous image data with the size of the image data after compression. If the size of the image data after compression is smaller than the size of the image data before compression, select the image data to transfer the compressed image data. If the size of the image data after compression is larger than or equal to the size of the image data before compression, the image data before compression is selected as the image data to be transferred, and the selected image data is selected as at least one other image data. If the transferred image data is compressed in the image forming apparatus that has been transferred to the image forming apparatus and has received the image data transfer, the image Decompresses the over data, prints the image data.

  The image memory of the image forming apparatus that receives the image data is less likely to be occupied by the image data, and other image processing processes can operate using sufficient image memory. In addition, it is possible to reduce the network traffic and suppress the performance degradation of the operation performed by other devices via the network. Furthermore, according to the user's request, it can be selected whether to give priority to the reduction of network traffic or the shortening of the expansion process.

  In the image forming system 1 of the present invention, a plurality of image forming apparatuses 2 are connected via a network 3 as shown in the block diagram of FIG. The network 3 may be a general-purpose network configured by a LAN such as Ethernet (registered trademark) or a serial I / F such as IEEE1394, or may be a network specialized for an image forming apparatus.

  Each image forming apparatus 2 includes a controller 4, a scanner engine 5, and a plotter engine 6 as shown in the configuration diagram of FIG. 2. In the controller 4, the image transfer bus 41 is connected to the CPU bus 43 via the bridge 42. The image transfer bus 41 includes a compression unit 411, a comparison / selection unit 412, an expansion unit 413, an image memory 414, a DMAC (Direct Memory Access Controller) 415, a NIC (Network Interface Controller) 416, a scanner buffer 417, a plotter buffer 418, and a hard disk. 419 is connected. The image transfer bus 41 needs to transfer image data at a high speed, and may be a dedicated bus designed to transfer image data efficiently or may be a diverted general-purpose high-speed bus.

  The compression unit 411 generates compressed image data by compressing the original image data to be printed, and stores the compressed image data in the image memory 414. The compression method is arbitrary, and it is desirable to employ a compression method suitable for the original image data based on information such as binary image, multi-value image, monochrome, color, dither, and error diffusion. The comparison / selection unit 412 compares the size of the original image data and the size of the compressed image data, and if the size of the compressed data is smaller than the coefficient K times the size of the original image data, selects the compressed image data as data to be transferred. If the size of the compressed data is equal to or larger than the factor K times the size of the original image data, the original image data is selected as data to be transferred. When the original image data is selected as data to be transferred and when the compressed image data has been transferred, the compressed image data is released from the image memory 414. The decompression unit 413 creates original image data by decompressing the compressed image data.

  The image memory 414 is an area for storing image data. The image data input from the image input unit such as the scanner engine 5 and the image data sent from the network 3 through the NIC 416 are stored as they are, or the image data compressed or expanded is stored. This image data may be any kind of image, and for example, image data of various formats such as black and white / color, binary / multi-value, compression / non-compression, low resolution / high resolution, and the like can be considered. The image data stored on the image memory 414 is transferred to the plotter engine 6 at the time of printing, transmitted to the network 3 through the NIC 416, and stored in the hard disk 419.

  The DMAC 415 is a controller that transfers image data flowing through the image transfer bus 41 at high speed, and performs a process of transferring a large amount of data collectively. For example, when the image data sent to the scanner buffer 417 at the time of scanning is written to a specified area of the image memory 414 through the image transfer bus 41 and the image data is stored, the image data stored in the image memory 414 is stored in the hard disk 419. The image data stored in the image memory 414 at the time of printing is sent to the plotter buffer 418. The address to be written in the image memory 414 and the size of data to be transferred are designated in advance by the CPU 433.

  The NIC 416 is a module that controls the I / F with the network 3, receives image data and other data sent through the network 3, flows data to the image transfer bus 41 according to a request sent through the bus, and Data flowing on the transfer bus is transmitted to the network 3.

  The scanner buffer 417 temporarily stores and accumulates image data transferred through the scanner I / F 51, and outputs it in accordance with the bus cycle of the image transfer bus 41 in response to a request from the DMAC 415. The plotter buffer 418 temporarily stores the image data sent through the image transfer bus 41 and outputs it to the plotter engine 6 according to the speed of the plotter I / F 61. The hard disk 419 stores image data and other information.

  The bridge 42 absorbs the speed difference and the bus width difference between the CPU bus 43 and the image transfer bus 41, and performs endian conversion for defining the byte order within each word in each memory. For example, access from the CPU 433 to the image memory 414 is realized by the bridge 42 converting a CPU bus access cycle by the CPU 433 into an image transfer bus access cycle.

  A ROM 431 and a RAM 432 are connected to the CPU bus 43 and the CPU 433 is directly connected thereto. The ROM 431 stores a program for operating the CPU 433, and the RAM 432 is used for temporary work of the CPU 433. The CPU 433 outputs instructions such as start and stop of scanning for the scanner engine 5, start and stop of printing for the plotter engine 6, and start and stop of data transfer for the DMAC 415, and controls the operation of the controller 4.

  The scanner engine 5 captures an image, creates image data, and transfers the image data to the scanner buffer 417 through the scanner I / F 51. The plotter engine 6 takes in the image data sent from the plotter buffer 418 through the plotter I / F 61 and prints it.

  At the time of linked copying in which a plurality of image forming apparatuses 2 perform print processing in parallel, for example, the image forming apparatus 2a becomes a master that transmits image data, and the remaining image forming apparatuses 2b, 2c, and 2d become slaves that receive the image data. The image data is transmitted and received through the network 3. A flow of concatenated copy in which the master transfers the original image data captured from the scanner engine 5 by the scan process to the slave and prints from the master and a plurality of slaves will be described. Note that the master may concatenately copy image data stored in the hard disk 419, image data captured from the network, or the like as original image data.

  FIG. 3 is a flowchart of scan processing in the master. The CPU 433 requests the scanner engine 5 to start scanning (step S10), and requests the DMAC 415 to start DMA transfer for transferring image data from the scanner buffer 417 to the image memory 412 (step S11). The scanner engine 5 accumulates the read image data in the scanner buffer 417 as needed (step S12), and the DMAC 415 reads image data of a preset size from the scanner buffer 417 and transfers it to the image memory 412 through the image transfer bus 41. (Step S13). Reading and storing image data by the scanner engine 5 and transferring and storing image data by the DMAC 415 are repeated (step S14), the scanner engine 5 stores image data for one page in the scanner buffer 417, and the DMAC 415 stores one page. When the image data is stored in the image memory 414, the CPU 433 requests the scanner engine 5 to end scanning (step S15), and then requests the DMAC 415 to end DMA transfer (step S16). The CPU 433 requests the DMAC 415 to start DMA transfer for transferring the image data from the image memory 414 to the hard disk 419 (step S17), and the DMAC 415 reads out image data of a preset size from the image memory 414 to obtain an image. The data is transferred to the hard disk 419 through the transfer bus 41 and stored (step S18), and all image data is transferred and stored (step S19), and the process is terminated.

  FIG. 4 is a flowchart of the transfer process from the master to the slave. The master DMAC 415 secures an original image area in a size that can store the original image data in the master image memory 414 (step S20). For example, when the size of the original image data is 4 MB, an original image area for 4 MB is secured as shown in FIG. The master DMAC 415 reads the original image data from the master hard disk 419 and develops it in the reserved original image area (step S21). On the master side, the printing process of the original image data can be performed in parallel with other processes from the time when the development is completed. After the expansion, the master compression unit 411 compresses the expanded original image data to create compressed image data, and secures and stores a compressed image area in the master image memory 414 (step S22). For example, as shown in FIG. 5A, when the size of the original image data is 4 MB and the size of the compressed image data is ½ of 2 MB, a compressed image area of 2 MB is secured in the image memory 414. .

  The master comparison / selection unit 412 compares the size of the original image data with the size of the compressed image data (step S23). If the size of the compressed data is smaller than the size of the original image data, the master comparison / selection unit 412 transfers the compressed image data. When the size of the compressed data is larger than or the same as the size of the original image data, the original image data is selected as the data to be transferred (step S25). The compressed image data is selected from the master image memory 414. Open (step S26). When the entropy of the original image data is high, the size of the compressed image data may be equal to or larger than the size of the original image data depending on the compression method, and instead of transmitting the original image data, the compressed image data is transferred. However, the effect of reducing the amount of data is expected to be small. In such a case, it is possible to prevent the master side from transferring the compressed image data and the slave from performing unnecessary decompression processing.

  When the master comparison / selection unit 412 selects data to be transferred, the master DMAC 415 starts to transfer the selected image data to the slave. The master DMAC 415 performs transfer to the slave via the master and slave NICs 416. The master DMAC 415 notifies the slave DMAC 415 of the size of the selected image data (step S27), and the slave DMAC 415 secures a transfer image area corresponding to the notified transfer data size in the slave image memory 414. Then, the master DMAC 415 is notified (step S28). For example, when the transfer data is 2 MB compressed image data, a 2 MB transfer image area is secured as shown in FIG. 5B, and when the transfer data is 4 MB original image data, 4 MB A transfer image area is secured. For example, when transferring image data to a plurality of slaves through IEEE1394 capable of one-to-many transfer, transfer is started once transfer image areas are secured in the image memories of all slaves. Do.

  The master DMAC 415 receives from the slave DMAC 415 the notification of the end of securing the transfer image area, reads the selected image data from the master image memory 414, and starts transfer to the slave (step S29). The slave DMAC 415 stores the image data received through the slave NIC 416 in the transfer image area of the slave image memory 414 (step S30). When the image data stored in the transfer image area is compressed image data, the slave decompression unit 413 secures the decompressed image area in the slave image memory 414 where the original image data can be stored, and transfers the transfer image area. The compressed image data is sequentially decompressed and stored in the decompressed image area (step S32), and if it is original image data, the decompression processing is not performed. For example, when the original image data is compressed image data of 4 MB, a 4 MB expanded image area is secured as shown in FIG. The master DMAC 415 repeats the transfer until all the image data is transferred (step S33), the slave DMAC 415 receives and stores all the image data, and receives the compressed image data until all the decompression unit 413 performs the decompression process. The storage and decompression process is repeated (step S34). When the data to be transferred is compressed image data, the master comparison / selection unit 412 releases the compressed image area in the master image memory 414 as shown in FIG. 6A after the transfer is completed (step S35), and the slave The decompression unit 413 releases the transfer image area as shown in FIG. 6B after the decompression process is completed (step S36). On the slave side, the printing process of the original image data can be performed in parallel with other processes from the end of the decompression process.

  FIG. 7 is a flowchart of the printing process. Similar processing is performed in both the master and the slave. The CPU 433 requests the DMAC 415 to start DMA transfer for transferring original image data from the image memory 414 to the plotter buffer 418 (step S40), and requests the plotter engine 5 to start printing (step S41). The DMAC 415 transfers and stores the original image data from the image memory 414 to the plotter buffer 418 through the image transfer bus (step S42), and the plotter engine 5 reads and prints the original image data stored in the plotter buffer 418 (step S42). S43). The transfer and storage of the original image data by the DMAC 415 and the reading and printing of the original image data by the plotter engine 6 are repeated (step S44), and the CPU 433 transfers all of the original image data of the image memory 414 to the plotter buffer 418 and the plotter engine. When printing is started from 5, the DMAC 415 is requested to end DMA transfer (step S45), and the plotter engine is requested to end printing (step S46).

  Thus, the traffic on the network 3 can be reduced by performing the transfer on the network 3 using the compressed image data. This is more effective as the number of slaves increases. In addition, when the size of the compressed image data is larger than the size of the original image data, the use of the original image data can prevent performance degradation.

  The slave may decompress the transferred compressed image in addition to sequentially decompressing the transferred compressed image. The slave is compressed except for the image data being printed, and it is sufficient to decompress the compressed image data when performing the printing process. Therefore, the required image memory capacity is small, and the slave image memory 414 is free. A large amount of capacity is ensured, and a decrease in print processing performance is suppressed.

  The comparison / selection unit 412 included in each image processing apparatus 2 in the image forming system according to the second embodiment uses the coefficient K in the comparison between the size of the original image data and the size of the compressed image data, and the size of the compressed data is the original size. If the image data size is smaller than the coefficient K times, the compressed image data is selected as data to be transferred. If the compressed data size is larger than or equal to the original image data size K, the original image data is transferred. Select as data to be used. The coefficient K is predetermined within a range of 0 <K <1. For example, if the size of the original image data is 4 MB when the coefficient K is set to 0.8, the original image data is transferred when the size of the compressed image data is 3.2 MB or larger. When the size of the compressed image data is smaller than 3.2 MB, the compressed image data is transferred. Other configurations are the same as those of the image forming system in the first embodiment. Even if the size of the compressed image data is smaller than the size of the original image data by using the coefficient K, the master side transfers the compressed image data and the slave is wasted if the effect of reducing the data amount is considered to be small. Can be prevented.

  As shown in FIG. 8, the image forming system according to the third embodiment includes an operation unit 7 in each image forming apparatus 2, and the other configuration is the same as the configuration of the image forming system in the second embodiment. . The operation unit 8 is connected to the CPU bus 43 of the controller 4, receives the input of the coefficient K from the user, and sets the coefficient K in the comparison / selection unit 412. As a result, it is possible to perform an operation suitable for the user's intention, such as increasing the coefficient K to give priority to a reduction in traffic on the network 3 or reducing it to give priority to shortening the decompression processing time of the compressed image data.

1 is a configuration diagram of an image forming system. 1 is a configuration diagram of an image forming apparatus. It is a flowchart of a scanning process. It is a flowchart of a transfer process. It is an example of the contents of a master and a slave image memory. It is an example of contents after releasing the master and slave image memories. It is a flowchart of a printing process. FIG. 10 is a configuration diagram of an image forming apparatus according to a third embodiment.

Explanation of symbols

1; image forming system, 2; image forming apparatus, 3; network,
4; controller, 5; scanner engine, 6; plotter engine,
7; operation unit, 41; image transfer bus, 42; bridge, 43; CPU bus,
51; Scanner I / F, 61; Plotter I / F, 411; Compression unit,
412; comparison selection unit, 413; expansion unit, 414; image memory,
415; DMAC, 416; scanner buffer, 417; plotter buffer,
418; NIC, 419; hard disk, 431; ROM, 432; RAM,
433; CPU

Claims (5)

In an image forming system for connecting a plurality of image forming apparatuses via a network and transferring image data from any one of the image forming apparatuses to at least one other image forming apparatus.
Each of the image forming apparatuses includes a compression unit, a comparison selection unit, and an expansion unit.
The compression unit compresses image data to be transferred,
The comparison / selection unit compares the size of the image data before compression with the size of the image data after compression, and if the size of the image data after compression is smaller than the size of the image data before compression, the image data after compression If the image data size after compression is larger than or the same as the size of the image data before compression, select the image data before compression as the image data to be transferred,
The decompression unit decompresses the received compressed image data. In an image forming system for connecting a plurality of image forming apparatuses via a network and transferring image data from any one of the image forming apparatuses to at least one other image forming apparatus.
Each of the image forming apparatuses includes a compression unit, a comparison selection unit, and an expansion unit.
The compression unit compresses image data to be transferred,
The comparison / selection unit compares a size obtained by multiplying a size of image data before compression by a coefficient larger than 0 and smaller than 1 and a size of image data after compression, and a size obtained by multiplying image data before compression by the coefficient. If the size of the image data after compression is smaller, select the image data to be transferred as compressed image data, and the size of the image data after compression is larger or the same as the size obtained by multiplying the image data before compression by the coefficient. If it is, select the image data before compression as the image data to be transferred,
The decompression unit decompresses the received compressed image data.   The image forming system according to claim 2, wherein a user can set the coefficient.   The image forming system according to claim 1, wherein a printing operation is performed by both the transfer source image forming apparatus and the transfer destination image forming apparatus. Prints image data formed or read image data in any one of a plurality of image forming apparatuses connected via a network, compresses the image data, and compresses the size and compression of the image data before compression. Compare the size of the post-compression image data. If the post-compression image data size is smaller than the pre-compression image data size, select the post-compression image data as the image data to be transferred. If the size of the image data after compression is larger than or the same as the size, select the image data before compression as the image data to be transferred, transfer the selected image data to at least one other image forming apparatus,
An image forming method for receiving image data transfer, wherein, when the transferred image data is compressed, the image data is expanded and the image data is printed.

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