JP2006018406A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can prevent an underrun or an overrun due to transmission to a plotter, can permit access from other devices, and accordingly has reduced dead time due to the nonuse of a bus, by observing the transfer quantity of data transferred on the bus as a general-purpose bus and by obtaining the status of use of the bus based on the transfer quantity, that is to say, the magnitude of a load on the bus. <P>SOLUTION: The image forming apparatus comprises a scanner controller 21 which controls data read by a scanner 20 and controls data transfer to a controller ASIC14 on a PCI bus 15; a plotter controller 23 which transfers data from the controller ASIC14 to a plotter 22 by a request form the controller ASIC14; option devices A24, B25 each having an arbitrary function; and the controller ASIC14 which has a bus arbiter 26 for controlling the right of use of the bus on the PCI bus 15, a bus monitor 27 for monitoring data on the bus, and an ASIC28 having a function for managing the data volume. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly, to a data transfer method for managing data transfer of each device connected on a PCI bus to improve bus specification efficiency.

2. Description of the Related Art Conventionally, as an image forming apparatus, there is a composite copying machine (MFP) having a composite function such as a copy, a printer, and a FAX. In such a composite copying machine, an image read by a scanner is stored in an image memory or a local storage. Alternatively, the operation of transferring the image data instructed from the host computer to the plotter is performed by parallel processing. In addition, an MFP can be provided with various functions such as changing the image format by attaching an optional device on the bus for image transfer.
In recent years, with improvement in engine performance, engine writing / reading speed has been increased. The situation is the same in the MFP, and the load on the bus for transferring both write data and read data cannot be ignored due to the improvement of the transfer performance of the engine. As the types of image data are diversified, the size of the image data is, for example, 256 tones, 600 dpi A4 size data is about 36 MB, and for RGB three colors, it is 108 MB.
As the amount of data per page increases in this way, the amount of data transferred within one line cycle also increases in proportion to this, so that it is necessary to further increase the bus transfer rate within one line cycle. However, even in a general-purpose bus such as a PCI capable of high-speed transfer, the load on the bus is large, and an increase in bus width and an increase in bus frequency are being studied. However, implementation is difficult due to cost and hardware scale / constraints.
Therefore, it is conceivable to prevent data loss by efficiently controlling each bus master connected to the general-purpose bus. However, it is difficult to control, and as disclosed in Japanese Patent Application Laid-Open No. 2000-332924, there is known a method for preventing data loss and the like by always setting the priority of the scanner and plotter to a high priority.
JP 2000-332924 A

However, although the image transfer necessary for the image forming apparatus can be protected by the conventional technique disclosed in Patent Document 1, since the priority order of the scanner and the plotter is not lowered, it is optional when there are other optional devices. There is a problem that transfer of devices is significantly limited. In other words, depending on the optional device used, there is a device that must transfer the amount of data determined by the specification within a certain time.
In view of such problems, the present invention observes the transfer amount of data transferred on a general-purpose bus, and obtains the bus usage status, that is, the load applied to the bus based on the transfer amount. Since an underrun or overrun can be prevented by transfer of a plotter, and access to other devices can be permitted, an image forming apparatus that reduces the dead time due to the bus not being used is provided. For the purpose.

In order to solve such a problem, the present invention provides a scanner controller that controls data read by a scanner that reads an original image and performs photoelectric conversion, and controls data transfer to the controller, and Controls the right to use the plotter controller that transfers data from the controller to the plotter that prints the printed image on the recording paper according to the request, at least one optional device having an arbitrary function, and the bus on the PCI bus An image forming apparatus comprising an arbiter and a controller that monitors data on the PCI bus and manages the amount of data, wherein the controller processes a large amount of data by high-speed transfer within one line period Scanners, plotters, and optional devices are transferring on the PCI bus To, by counting the image data transfer amount of the various transfer data, characterized by managing the transfer amount during any time.
In the present invention, a device such as a scanner or plotter that requires high-speed transfer in order to process a large amount of data within one line period, or other optional device is performing transfer on the PCI bus for an arbitrary period of time. It manages how much data can be transferred. This makes it possible to determine whether each device can process the designated transfer amount without delay.
According to a second aspect of the invention, the controller can change the setting of the PCI bus based on the counted image data transfer amount.
The present invention is a means for preventing system failure. Based on the data transfer amount obtained in claim 1, when the PCI bus is expandable, the bus width is changed and the clock frequency used by the bus is increased. In this way, the processing speed is increased so that data transfer can be performed without excess or deficiency.
According to a third aspect of the present invention, the controller displays / notifies the data transfer status of each device on the PCI bus based on the counted image data transfer amount.
The present invention displays and notifies the data transfer status of each device on the PCI bus based on the data transfer amount obtained in claim 1. As a result, it can be understood which device is burdening the transfer of the PCI bus, and when the load on the bus is large, the failure of the bus can be prevented by changing the setting of a device that can reduce the load.

According to the first aspect of the present invention, when the controller of the image forming apparatus performs transfer on the PCI bus by a device that requires high-speed transfer in order to process a large amount of data within one line cycle. By counting the transfer amount of image data of transfer data, it manages how much transfer can be performed during an arbitrary time, so it is possible to judge whether each device can process the specified transfer amount without delay. .
According to the second aspect of the present invention, since the PCI bus setting can be changed based on the image data transfer amount counted by the controller, it is possible to prevent a general-purpose bus specification over, that is, a system failure, and efficient transfer. It can be performed.
According to the third aspect of the present invention, since the data transfer status of each device on the PCI bus is displayed / notified based on the image data transfer amount counted by the controller, system failure can be prevented without changing the system configuration. it can.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .
As an example of the image forming apparatus of the present invention, a description will be given below of a case where the present invention is a digital copying machine such as an MFP (Multi Function Printer) and a PCI bus is used as a general-purpose bus.
FIG. 1 is a block diagram showing an example of a controller configuration in the present invention. The controller 100 reads the image data from the CPU 1 and the scanner that control the controller as a whole, stores the image data sent from the ENGINE 2 and the ENGINE 2 for creating the stored image data, and processes the image data. SDRAM 3 for storage, HDD 4 serving as a storage device for storing a large amount of image data and job history, an operation unit 5 for setting prints and displaying a print state, and printers such as ROM 6, CARD 7, and FONT 8 Program device 9 for controlling the entire system including the FAX / scanner, NVRAM 10 for recording system log / system setting / log information, NIC 11 for connecting printer to LAN, and compressing image data And decompress the compressed data A compression / decompression unit having a function, an FCU 12 that performs a FAX control, an IEEE 1284 (13) for simultaneously transferring data using a plurality of signal lines, a controller ASIC 14 for controlling these devices, and an ASIC 14 And a PCI bus 15 for connecting ENGINE2, FCU12, IEEE1284 (13) and the like.

The document image read as shown in FIG. 1 is stored as it is in the SDRAM 3 via the PCI bus 15 from the ENGINE side, or once read out from the SDRAM 3 and compressed by the compression / decompressor and then stored in the SDRAM 3 again. . Although other storage methods exist, the present invention will be described by limiting only the main storage method. Further, it is assumed that an image processing controller 16 for converting image data into various image formats is connected to the PCI bus 15 as an example. The image data once stored in the SDRAM 3 is transferred to the image processing controller 16 through the PCI bus 15, and after appropriate processing is performed by the image processing controller 16, the format-converted data is transferred to the SDRAM 3 via the PCI bus 15. Is written.
FIG. 2 is a block diagram of devices connected to a bus when a PCI bus is used as a general-purpose bus. The same components will be described with the same reference numerals. A scanner controller 21 that controls data read by the scanner 20 on the PCI bus 15 and controls data transfer to the controller ASIC 14, and a plotter controller that transfers data from the controller ASIC 14 to the plotter 22 in response to a request from the controller ASIC 14. 23, optional devices A24 and B25 having arbitrary functions, a bus arbiter 26 for controlling the right to use the bus on the PCI bus 15, a bus monitor 27 for monitoring data on the bus, and a function for managing the amount of data. The controller ASIC 14 having the ASIC 28 is configured. Although not shown in FIG. 2, various optional devices can be connected to the PCI bus 15 to add a plurality of functions to the digital copying machine.

Example 1
In the invention of the first embodiment, devices such as the scanner 20 and the plotter 22 that require high-speed transfer in order to process a large amount of data within one line period, and other optional devices 24 and 25 perform transfer on the PCI bus 15. It manages how much transfer can be performed during an arbitrary time. This makes it possible to determine whether each device can process the designated transfer amount without delay.
FIG. 3 is a timing chart showing the basic movement of each signal on the PCI bus when image transfer is performed. Each signal is LSYNC: line synchronization signal, DREQ: data request, DATA: data required for one line, XREQ: bus request, XGNT: bus grant, TRANZ: bus transaction, PCICLK: clock, XFRAME: FRAME signal, XDEVSEL: DEVSEL signal, XIRDY: IRDY signal, XTRDY: TRDY signal, AD [31: 0]: address signal, CBE: command / byte enable signal.
In FIG. 3, when the controller ASIC 14 asserts XREQ from each device, the ASIC asserts XGNT to one of them to give the right to use the bus. The device that has become the bus master can transfer data while being given the right to use the bus. When the requested transfer amount has been processed, XREQ is deasserted and the right to use the bus is returned to the ASIC. Basically, it is known that the right of use is passed in order in a round robin format so that each device can be given a bus evenly. However, in the image forming processing apparatus, if the transfer of the scanner, plotter, etc. is not completed while LSYNC is asserted, the image will not be printed normally. Therefore, in general, priority is given to the bus use right, and processing is performed so that such a problem does not occur by assigning higher priority to the scanner and the plotter. It is well known that a lot of bus time is allocated to scanners and plotters.
However, as a problem here, if the scanner and plotter always have a high priority, a device with a low priority cannot readily use the bus. Furthermore, such devices have a small bus occupancy time allocation, and some devices must perform predetermined transfers within a certain period of time, otherwise the system may hang due to an error or the like There is sex.

(Example 2)
The invention of the second embodiment is for preventing the system from failing. If the PCI bus can be expanded based on the data transfer amount obtained in the first embodiment, the bus width is changed or the bus is changed. By increasing the processing frequency by increasing the clock frequency to be used, data transfer can be performed without excess or deficiency. However, if expansion is performed as it is, the change of the system becomes large, and it takes time to change the software that controls the hardware, so it is desirable to make the change as small as possible. Therefore, by selecting an optimal change from the obtained data amount, it is possible to reduce the influence of the entire system and to prevent the system from failing.
Further, by knowing the transfer amount of each device, adjusting the transfer amount of a device that performs transfer of unit time more than necessary, it is possible to assign the transfer amount to other devices that require more. For example, when a device that stores data in an SDRAM is connected via a network, the bus has a short occupancy time because this device has no restriction on transfer time. In this case, if a bus usage right is allocated more than necessary to a scanner that processes a large amount of data, the device is processed for a long time. Therefore, by calculating the extra time given to the scanner, the extra processing time can be assigned to the storage device, and the bus is not wasted and is effectively used.

Example 3
The invention of the third embodiment displays and notifies the data transfer status of each device on the PCI bus based on the data transfer amount obtained in the first embodiment. As a result, it can be understood which device is burdening the transfer of the PCI bus, and when the load on the bus is large, the failure of the bus can be prevented by changing the setting of the device that can reduce the load. In addition, it is possible to easily change the system configuration or the like by knowing which device has applied what level of load when the bus fails.

It is the block diagram which showed an example of the controller structure of this invention. It is a block diagram of a device connected to a bus when a PCI bus is used as a general-purpose bus. It is a timing chart which shows the fundamental motion of each signal on the PCI bus | bath when performing image transfer.

Explanation of symbols

  14 controller ASIC, 15 PCI bus, 21 scanner controller, 22 plotter, 23 plotter controller, A24, B25 optional device, 26 bus arbiter, 27 bus monitor, 28 ASIC

Claims (3)

From the controller to a scanner controller that controls data read by a scanner that reads a document image and performs photoelectric conversion, and controls data transfer to the controller, and a plotter that prints a print image on recording paper in response to a request from the controller Data amount is managed by monitoring the data on the PCI bus, the plotter controller that transfers the data, at least one optional device with any function, the arbiter that controls the right to use the bus on the PCI bus An image forming apparatus comprising:
The controller counts the image data transfer amount of various transfer data when the scanner, plotter, and optional device that process a large amount of data at high speed transfer within one line cycle are transferring on the PCI bus. An image forming apparatus that manages a transfer amount during an arbitrary time.   The image forming apparatus according to claim 1, wherein the controller is configured to change the setting of the PCI bus based on the counted image data transfer amount.   The image forming apparatus according to claim 1, wherein the controller displays and notifies a data transfer status of each device on the PCI bus based on the counted image data transfer amount.

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