JP2010098426A - Controller, image forming apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize transfer condition for transferring data to a data transmission channel according to the amount of data being transmitted through the data transmission channel. <P>SOLUTION: The controller includes: a primary PCI bus 61 for transferring data, a secondary PCI bus 164 for transferring data and connected to the primary PCI bus 61, and a setting means for setting a transfer condition for transferring data using the primary PCI bus 61 and the secondary PCI bus 164 on the basis of the transfer rate required for the device issuing a request to use the primary PCI bus 61. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device, an image forming apparatus, and a program.

  In an image forming apparatus such as a printer or a copying machine, various types of image processing such as color processing and gradation processing are performed on image data. However, in recent years, user needs related to image editing and image representation have been diversified. For this reason, the function expansion device is equipped with special image processing functions related to the OCR (Optical Character Recognition) function, color conversion processing, filter processing, etc. An image forming apparatus using the function expansion device as an optional device is provided. In that case, the function expansion device is connected to the image forming apparatus via a data transmission path (bus), and the image forming apparatus and the function expansion apparatus share the data transmission path to transfer data.

  For example, in Patent Document 1, in a data transfer method for a parallel processing system in which a plurality of processing elements share and use a transmission path, the occupation time of the right to use the transmission path of each processing element is set separately for each processing element A technique for finely setting the priority of the data transmission capability in the bus is described.

JP 2001-238019 A

In general, when different apparatuses such as an image forming apparatus and a function expansion apparatus share a data transmission path, data transmission on the data transmission path may be performed depending on the operating state of the apparatus connected to the data transmission path. It may be obstructed, and the free band generated in the data transmission path on the other side may increase.
An object of the present invention is to optimize transfer conditions when data is transferred to a data transmission path in accordance with the amount of data transmitted through the data transmission path.

  The invention according to claim 1 is a first data transfer path for transferring data, a second data transfer path for transferring data and connected to the first data transfer path, and the first data Based on the transfer rate required for the device making a use request for the first data transfer path, the transfer condition when transferring data using the transfer path and the second data transfer path And a setting means for setting.

The invention according to claim 2 further comprises arbitration means for arbitrating permission / non-permission of use of the first data transfer path for the device making a request for use of the first data transfer path. The setting means sets, based on the transfer speed, the amount of data to be transferred at one use permission given from the arbitration means as the transfer condition or the time to occupy the first data transfer path. The control device according to claim 1.
The invention according to claim 3 further comprises arbitration means for arbitrating use permission / non-permission of the first data transfer path for the device making a request for use of the first data transfer path. The setting unit monitors the transfer rate required for the device based on the use permission from the arbitration unit, and sets the transfer condition according to the transfer rate in the device to which the use permission is granted. The control device according to claim 1, wherein the control device is set.
According to a fourth aspect of the present invention, the setting unit sets the transfer condition in consideration of an elapsed time since the last use permission is sent to the device in the device to which the use permission is granted. The control device according to claim 3.
The invention according to claim 5 further includes arbitration means for arbitrating use permission / non-permission of the first data transfer path with respect to the device making a request to use the first data transfer path. The setting unit holds a plurality of transfer conditions with different amounts of data transferred from the arbitration unit at one use permission, and sets any one of the plurality of transfer conditions. The control device according to claim 1.

  According to a sixth aspect of the present invention, there is provided image forming means for forming an image based on image data, a first data transfer path to which the image forming means is connected and transferring the image data, and transferring the image data. Transfer conditions for transferring the image data using the second data transfer path connected to the first data transfer path, the first data transfer path, and the second data transfer path An image forming apparatus comprising: a setting unit configured to set an image based on a transfer speed required for the image forming unit that is requesting use of the first data transfer path.

According to a seventh aspect of the present invention, the setting unit transfers the image forming unit with one use permission given from an arbitration unit that arbitrates use permission / non-permission of the first data transfer path. The image forming apparatus according to claim 6, wherein an amount of image data to be performed or a time for occupying the first data transfer path is set as the transfer condition.
According to an eighth aspect of the present invention, the setting unit arbitrates a transfer speed required for the image forming unit to arbitrate use permission / non-permission of the first data transfer path with respect to the image forming unit. 7. The image formation according to claim 6, wherein monitoring is performed based on a use permission from the means, and the transfer condition is set according to a transfer speed required for the image forming means to which the use permission is given. Device.
According to a ninth aspect of the present invention, the setting unit transfers the transfer in consideration of an elapsed time since the previous use permission is sent to the image forming unit in the image forming unit to which the use permission is given. The image forming apparatus according to claim 8, wherein conditions are set.
According to a tenth aspect of the present invention, the setting unit transfers the image forming unit with one use permission given from an arbitration unit that arbitrates use permission / non-permission of the first data transfer path. 7. The image forming apparatus according to claim 6, wherein a plurality of transfer conditions having different amounts of image data to be held are held, and any one of the plurality of transfer conditions is set.

  According to an eleventh aspect of the present invention, there is provided a function of monitoring a transfer rate required for a device that is requesting a computer to use a first data transfer path through which data is transferred; When transferring data using the data transfer path and the second data transfer path connected to the first data transfer path, the device needs transfer conditions for transferring the data. And a function for setting based on a transfer rate.

According to the first aspect of the present invention, as compared with the case where the present invention is not adopted, the transfer condition for transferring data to the data transmission path is optimized in accordance with the amount of data transmitted through the data transmission path. be able to.
According to claim 2 of the present invention, the transfer capability of the first data transfer path can be used more effectively than when the present invention is not adopted.
According to the third aspect of the present invention, when data is transferred using the first data transfer path and the second data transfer path, the first data transfer is compared with the case where the present invention is not adopted. It is possible to set transfer conditions that guarantee transfer of data to a device connected to the path and that effectively use the transfer capability of the first data transfer path.
According to claim 4 of the present invention, the continuity of data between the previous data transfer and the current data transfer is determined, and the transfer of data to the device in the first data transfer path is guaranteed, Further, it is possible to more accurately determine the data transfer condition that effectively uses the transfer capability of the first data transfer path as compared with the case where the present invention is not adopted.
According to claim 5 of the present invention, as compared with the case where the present invention is not adopted, the transfer of data to the device in the first data transfer path is guaranteed, and the transfer capability of the first data transfer path is increased. Data transfer conditions that are used effectively can be set in accordance with the amount of data transferred through the first data transfer path.

According to the sixth aspect of the present invention, compared with the case where the present invention is not adopted, the image data is transferred to the data transmission line in accordance with the amount of data transmitted through the data transmission line, compared to the case where the present invention is not adopted. It is possible to optimize transfer conditions when transferring.
According to the seventh aspect of the present invention, as compared with the case where the present invention is not adopted, the transfer of the image data to the image forming means in the first data transfer path is ensured, and the transfer of the first data transfer path is ensured. The image data can be transferred while effectively using the capability.
According to the eighth aspect of the present invention, when transferring image data using the first data transfer path and the second data transfer path, the first data is compared with the case where the present invention is not adopted. Transfer conditions that guarantee transfer of image data to the image forming means on the transfer path and that effectively use the transfer capability of the first data transfer path can be set.
According to the ninth aspect of the present invention, the continuity of data between the previous data transfer and the current data transfer is determined, and the image data is transferred to the image forming means in the first data transfer path. The transfer condition of image data that guarantees and effectively uses the transfer capability of the first data transfer path can be determined more accurately than in the case where the present invention is not adopted.
According to the tenth aspect of the present invention, as compared with the case where the present invention is not adopted, the transfer of image data to the image forming means in the first data transfer path is guaranteed, and the first data transfer path It is possible to set the transfer condition of the image data that effectively uses the transfer capability according to the usage status of the first data transfer path.
According to the eleventh aspect of the present invention, as compared with the case where the present invention is not adopted, the transfer condition for transferring data to the data transmission path is optimized in accordance with the amount of data transmitted through the data transmission path. be able to.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
<Overall description of image forming apparatus>
FIG. 1 is a block diagram illustrating an example of the overall configuration of an image forming apparatus 1 to which the exemplary embodiment is applied. The image forming apparatus 1 shown in FIG. 1 includes a control unit 10 that controls the operation of the image forming apparatus 1 according to a predetermined program. In addition, the image forming apparatus 1 includes, as an example of a component (device) that executes various functions, a communication unit 31 that performs communication with a network that is an example of a communication unit such as a LAN (Local Area Network) or the Internet, and communication. A network interface (I / F) 21 that controls transmission / reception of data to / from the unit 31 is provided. Also, a card input / output unit 32 that is connected to a USB (Universal Serial Bus) port and inputs / outputs various information to / from an IC card, for example, and a USB interface that controls transmission / reception of data to / from the card input / output unit 32 (I / F) 22 is provided.

Further, the image forming apparatus 1 includes an operation panel 33 that receives an operation input from the user and displays various information for the user, and an operation panel interface (I / F) 23 that controls transmission and reception of data with the operation panel 33. I have. In addition, an image reading unit 34 that reads reflectance data of each color component from a document and generates image data, and a scanner interface (I / F) 24 that controls transmission and reception of data with the image reading unit 34 are provided.
Further, the image forming apparatus 1, as an example of an image forming unit, forms an image on a sheet based on image data (hereinafter also referred to as video data), and transmits / receives data to / from the image forming unit 35. Is provided with a video interface (I / F) 25. Here, as the image forming unit 35, for example, an electrophotographic image forming engine is used.
Further, the image forming apparatus 1 is configured with, for example, a hard disk drive (HDD), a flash memory, or the like, and includes an auxiliary storage unit 40 in which programs, data, and the like are stored.

The control unit 10 is executed by a CPU (Central Processing Unit) 11 that performs arithmetic processing when performing operation control in the image forming apparatus 1, a RAM (Random Access Memory) 12 that is used as a working memory of the CPU 11, and the CPU 11. A ROM (Read Only Memory) 13 is stored which stores various data used in the program. These are connected to each other by a system bus 63 and connected to a primary PCI (Peripheral Components Interconnect bus) bus 61 as an example of a first data transfer path through an ASIC_A 71 having a bus bridge function, an image processing function, and the like. ing.
The ASIC_A 71 is also connected to a video data storage unit 45 that stores video data to be subjected to image processing when image processing such as color processing and screen processing is executed by the ASIC_A 71.

Each of the network I / F 21, USB I / F 22, operation panel I / F 23, scanner I / F 24, and video I / F 25 is connected to the secondary PCI bus 62 in the apparatus main body, and has an ASIC_B 72 functioning as a bus bridge. Is connected to the primary PCI bus 61. The auxiliary storage unit 40 is also connected to the primary bus 61 via the ASIC_B 72.
The ASIC_B 72 has a function as a DMAC (Direct Memory Access Controller), and performs data transfer to various interfaces (I / F) connected to the secondary PCI bus 62 at high speed.

  A bus arbitration unit 50 as an example of arbitration means for arbitrating the bus use right of the primary PCI bus 61 is connected to the primary PCI bus 61 that interconnects each device via the ASIC_A 71 and the ASIC_B 72. Each device sends a request signal (REQ #) for acquiring the right to use the primary PCI bus 61 to the bus arbitration unit 50. The bus arbitration unit 50 arbitrates the bus use right request signal (REQ #) sent from each device, and then outputs a bus use permission / non-permission signal (GNT #) to each device. The use of the PCI bus 61 is permitted / not permitted. Since the primary PCI bus 61 performs handshaking of a request signal (REQ #) and a bus use permission / non-permission signal (GNT #), address information (address data) necessary for handshaking is defined for each device. The device to which the bus use right is given from the bus arbitration unit 50 outputs a bus use notification signal (FRAME #) notifying that the device starts data transfer to the primary PCI bus 61.

  The primary PCI bus 61 is connected to an image processing option device 100 as an example of a function expansion device configured to be externally attached to the main body of the image forming apparatus 1. The image processing option device 100 executes special image processing on video data that is a base when an image is formed in the image forming unit 35 on the main body side of the image forming apparatus 1, for example, a digital signal processor (Digital Signal Processor). The image processing unit 120 is provided as an example of the image processing means configured by (1). The image processing unit 120 performs special image processing that is not performed by the control unit 10 and ASIC_A 71 on the apparatus main body side that perform general image processing relating to color conversion processing, gradation processing, and the like.

That is, the control unit 10 on the apparatus body side analyzes image data in, for example, a PDL (Page Description Language) format, generates intermediate data, and prints the generated intermediate data expressed in an array of pixels. To develop (render) video data (raster image data). Further, the ASIC_A 71 performs color conversion processing for color-converting rendered video data into color system image data (YMCK) suitable for printing processing, and screen processing (gradation processing) for the color-converted video data. Etc.
On the other hand, the image processing unit 120 of the image processing option device 100 specifies a character by collating with a prestored pattern, for example, with respect to a handwritten character read by the image reading unit 34 or a printed character. For example, an OCR (Optical Character Recognition) function for converting character data (character data), color conversion processing for converting color data expressed in 256 gradations into color data of 16 palettes, Special image processing that is not normally performed by the control unit 10 on the apparatus body side, such as a function for performing image processing, compression processing, or the like suitable for the character portion and the image portion, respectively, by separating the image area from the character portion and the image portion. Do.

  Such an image processing function included in the image processing option device 100 is set in accordance with user needs regarding image editing, image expression, and the like. As a result, the user selects the image processing option device 100 having an image processing function that meets his needs, and attaches the image processing option device 100 to the main body of the image forming apparatus 1 as an option device. In that case, as described above, the image processing option device 100 is connected to the primary PCI bus 61 in the primary PCI bus 61 of the main body of the image forming apparatus 1.

  In addition, the image processing option device 100 includes a control unit 110 that performs operation control and the like in the image processing option device 100 in accordance with a predetermined program. The control unit 110 includes a CPU 111 that performs arithmetic processing when performing operation control in the image processing option device 100, a RAM 112 that is used as a working memory of the CPU 111, various data that are used in programs executed by the CPU 111, and the like. A ROM 113 is provided. The CPU 111 has a function as a DMAC, and performs data transfer to each device connected to the secondary PCI bus 164 at a high speed.

In the image processing option device 100, the control unit 110 and the image processing unit 120 are connected to a secondary PCI bus 164 as an example of a second data transfer path. The secondary PCI bus 164 of the image processing option apparatus 100 is connected to the primary PCI bus 61 on the apparatus main body via a PCI-PCI bus bridge 200 as an example of a control apparatus that performs data transfer control.
The secondary PCI bus 164 is connected to a bus arbitration unit 130 that arbitrates the right to use the bus in the secondary PCI bus 164. Then, the bus arbitration unit 130 performs arbitration regarding permission / non-permission of use of the secondary PCI bus 164 for each device connected to the secondary PCI bus 164.

<Description of PCI-PCI bus bridge>
Next, the PCI-PCI bus bridge 200 provided in the image processing option device 100 will be described.
The PCI-PCI bus bridge 200 according to the present embodiment uses the primary PCI bus 61 through which video data is transmitted (transferred) when performing data transfer control between the primary PCI bus 61 and the secondary PCI bus 164. To monitor. Then, the transfer rate (bandwidth) of data transferred via the primary PCI bus 61 between the device provided in the image processing option apparatus 100 and the device of the apparatus main body is changed according to the use status of the primary PCI bus 61. Adjustment processing (hereinafter, also referred to as “data transfer bandwidth setting processing”).

  FIG. 2 is a block diagram illustrating a functional configuration of the PCI-PCI bus bridge 200. As shown in FIG. 2, the PCI-PCI bus bridge 200 according to the present embodiment includes a secondary PCI bus 164 to which devices in the image processing option device 100 are connected, and a primary PCI bus to which devices of the apparatus main body are connected. 61 includes a transfer control unit 210 that controls data transfer to and from 61. The PCI-PCI bus bridge 200 includes a PCI interface (PCI_I / F) 221 that controls transmission and reception of data between the primary PCI bus 61 and the transfer control unit 210, and a connection between the secondary PCI bus 164 and the transfer control unit 210. PCI interface (PCI_I / F) 222 for controlling transmission / reception of data. In addition, the transfer control unit 210 is connected to a data storage unit 280 as a buffer memory that temporarily stores data transferred between the primary PCI bus 61 and the secondary PCI bus 164.

The PCI-PCI bus bridge 200 is a data transfer as an example of a data transfer condition on the primary PCI bus 61 that is set when data is transferred between a device in the image processing option apparatus 100 and a device in the apparatus main body. A determination unit 230 that determines the speed (data transfer bandwidth) according to the usage status of the primary PCI bus 61 is provided. The determination unit 230 also includes a determination condition storage unit 260 including a register that stores determination conditions used when determining the data transfer bandwidth on the primary PCI bus 61. Here, the “data transfer speed” refers to the amount of image data transferred at one use permission given by the bus arbitration unit 50.
Further, the PCI-PCI bus bridge 200 includes an address information storage unit 240 that stores address data (address information) of a device to which the bus use right on the primary PCI bus 61 is granted by the bus arbitration unit 50, and an address information storage unit 240. If the address data stored in (1) is address data assigned to a device (for example, the video I / F 25) that requires the guarantee of the data transfer bandwidth, the device (video I) that requires the guarantee of the transfer bandwidth. / F25) includes a time measuring unit 250 that measures time from the start of data transfer to the start of the next data transfer.
The determination unit 230, the determination condition storage unit 260, the time measurement unit 250, and other components as necessary set the data transfer conditions (for example, the data transfer rate) on the primary PCI bus 61. And functions as control means for setting and controlling the data transfer conditions.
In addition, the PCI_I / F 221, the address information storage unit 240, the determination unit 230, and other components as necessary are necessary for the usage state of the primary PCI bus 61 (that is, a device using the primary PCI bus 61). It functions as a monitoring means for monitoring the transfer rate).

  The PCI-PCI bus bridge 200 is a low register composed of a register that stores a data transfer band (first data transfer band as an example of a transfer condition) used when the determination unit 230 determines that the data transfer band is set low. High bandwidth band register 271 includes a register for storing a data transfer band (second data transfer band as an example of a transfer condition) used when the determination unit 230 determines that the data transfer band is set high. A burst length storage unit 272 is provided. For example, assuming that the PCI-PCI bus bridge 200 transfers data between the primary PCI bus 61 and the secondary PCI bus 164 in 32-bit parallel, the low-band burst length storage unit 271 has 32 bits per clock during data transfer. Set value data having a burst length of 16 clocks representing the number of data (number of clocks) that can be transferred continuously is stored. The high band burst length storage unit 272 stores setting value data having a burst length of 64 clocks.

In the present embodiment, a register for setting two burst lengths is provided. However, a burst length storage unit composed of registers for setting three or more burst lengths may be provided. The burst length setting value data stored in the low-band burst length storage unit 271 and the high-band burst length storage unit 272 may be changed.
In addition, this register may store setting value data that defines the time for which the primary PCI bus 61 is occupied during data transfer, instead of the burst length that defines the data transfer rate. However, in that case, the PCI-PCI bus bridge 200 performs data transfer control between the primary PCI bus 61 and the secondary PCI bus 164 via the primary PCI bus 61 as an example of data transfer conditions. Adjustment processing for changing the transfer time of the data to be transferred according to the usage status of the primary PCI bus 61 is performed. Here, the “data transfer time” refers to the time for which the primary PCI bus 61 is occupied by one use permission given by the bus arbitration unit 50.

<Description of Determination Process Performed by PCI-PCI Bus Bridge for Data Transfer Rate>
Next, determination processing performed by the PCI-PCI bus bridge 200 according to the present embodiment regarding the data transfer rate on the primary PCI bus 61 will be described.
FIG. 3 is a flowchart showing the contents of the determination process performed by the PCI-PCI bus bridge 200 regarding the data transfer speed on the primary PCI bus 61. As shown in FIG. 3, the PCI_I / F 221 receives the bus use notification signal (FRAME #) output from the device to which the bus use right is given from the bus arbitration unit 50 from the primary PCI bus 61 (S101). Triggered by the PCI_I / F 221 receiving the bus use notification signal (FRAME #), the address information storage unit 240 uses the PCI_I to transfer the address data included in the transfer data for the device to which the bus use right of the primary PCI bus 61 is granted. Obtained from the primary PCI bus 61 via / F221 and stores this address data (S102).

Subsequently, the determination unit 230 determines whether or not the address data stored in the address information storage unit 240 is address data given to a device that requires guarantee of a data transfer band on the primary PCI bus 61. To do. In the present embodiment, it is assumed that the video I / F 25 is a device that requires guarantee of the data transfer band on the primary PCI bus 61. Therefore, specifically, the determination unit 230 determines whether the address data stored in the address information storage unit 240 is address data defined in the video I / F 25 (S103).
When the address data stored in the address information storage unit 240 is address data defined in the video I / F 25 (Yes in S104), the determination unit 230 performs time measurement in the time measurement unit 250. It is determined whether or not there is (S105). When the time measurement is being performed by the time measurement unit 250 (Yes in S106), the determination unit 230 resets the time measurement in the time measurement unit 250 and instructs the start of the next time measurement (S107). ). And the determination part 230 acquires the measurement time measured before resetting the time measurement from the time measurement part 250 (S108).

On the other hand, when the address data stored in the address information storage unit 240 is not the address data defined in the video I / F 25 (No in S104), the determination unit 230 is stored in the high-band burst length storage unit 272. The transfer control unit 210 is instructed to set the second data transfer band (for example, a burst length of 64 clocks) (S112). In this case, even if the data transfer band is set high, it is unlikely that the data transfer in the device (video I / F 25) that requires the guarantee of the data transfer band on the primary PCI bus 61 is hindered. is there.
If the address data stored in the address information storage unit 240 is address data defined in the video I / F 25, but the time measurement unit 250 has not performed time measurement (No in S106), The time measurement unit 250 is instructed to start time measurement (S109). Then, the determination unit 230 instructs the transfer control unit 210 to set the first data transfer band (for example, a burst length of 16 clocks) stored in the low-band burst length storage unit 271 (S113). In this case, if the data transfer band is set high, data transfer in the device (video I / F 25) that requires guarantee of the data transfer band on the primary PCI bus 61 may be hindered.

  Subsequent to step 108, the determination unit 230 uses the measurement time acquired from the time measurement unit 250 in step 108 as a determination reference time (for example, 10 seconds) as an example of the determination condition stored in the determination condition storage unit 260. Compare (S110). If the measurement time acquired from the time measurement unit 250 is equal to or greater than the determination reference time (Yes in S111), the determination unit 230 uses the second data transfer band (stored in the high-band burst length storage unit 272). For example, the transfer control unit 210 is instructed to set a burst length of 64 clocks (S112). In this case, even if the data transfer is performed by a device (video I / F 25) that requires the guarantee of the data transfer band on the primary PCI bus 61, the data transfer may be continuous with the previous data transfer. Is low. For this reason, even if the data transfer band is set high, for example, there is a low possibility that data transfer in the video I / F 25 is hindered.

On the other hand, when the measurement time acquired from the time measurement unit 250 is shorter than the determination reference time (No in S111), the determination unit 230 uses the first data transfer band (stored in the low-band burst length storage unit 271). For example, the transfer control unit 210 is instructed to set a burst length of 16 clocks (S113). In this case, there is a high possibility that the data transfer in the device (video I / F 25) requiring the guarantee of the data transfer band on the primary PCI bus 61 is a data transfer that is continuous with the previous data transfer. For this reason, if the data transfer band is set high, there is a high possibility that data transfer in the video I / F 25 is hindered, for example.
Then, after the instruction of the data transfer band to the transfer control unit 210 by the determination unit 230 is completed in step 112 and step 113, the process returns to step 101 and the reception processing of the bus use notification signal (FRAME #) is continued.

As described above, in the PCI-PCI bus bridge 200 according to the present embodiment, it is determined whether or not a bus use right is granted to a device (video I / F 25) that requires a guarantee of a data transfer band on the primary PCI bus 61. To do. For example, when the right to use the bus is given to a device other than the video I / F 25, the data transfer band used when the transfer control unit 210 controls the data transfer is stored in the high-band burst length storage unit 272. Is set to the second data transfer band.
For example, when the bus use right is given to the video I / F 25, the time (interval) between data transfer performed by the video I / F 25 is measured. In the PCI-PCI bus bridge 200, when the measurement time between the data transfer performed by the video I / F 25 is equal to or longer than a predetermined determination reference time, the transfer control unit 210 controls the data transfer. Is set to the second data transfer band stored in the high-band burst length storage unit 272. On the other hand, if the measurement time is shorter than the predetermined determination reference time, the data transfer band used when the transfer control unit 210 controls the data transfer is set to the first data transfer band stored in the first data transfer band. To do.

<Description of image processing procedure performed by image processing option device>
Next, the flow of processing for video data when image processing is performed by the image processing option device 100 will be described.
When the image processing option device 100 performs image processing, the control unit 110 of the image processing option device 100 activates the DMAC, and the image before image processing is started from the RAM 12 which is the main memory of the control unit 10 of the apparatus body. Data (pre-processing image data) is read out via the PCI-PCI bus bridge 200. Then, the image processing unit 120 of the image processing option device 100 executes predetermined image processing (for example, OCR processing) on the pre-processing image data. Then, the control unit 110 of the image processing option device 100 activates the DMAC, and the image processed image data (processed image data) is stored in the RAM 12 of the control unit 10 of the apparatus body via the PCI-PCI bus bridge 200. Write out.
In this case, the data transfer band set by the PCI-PCI bus bridge 200 when reading the pre-processing image data from the RAM 12 of the control unit 10 of the apparatus main body is the above-described process of FIG. 3 (data transfer band setting process). Is set. Similarly, the data transfer band set by the PCI-PCI bus bridge 200 when the processed image data is written to the RAM 12 of the control unit 10 of the apparatus main body is set by the above-described processing of FIG.

FIG. 4 is a flowchart showing the processing contents when the image processing option device 100 performs image processing on the video data. As shown in FIG. 4, first, the control unit 110 of the image processing option device 100 activates the DMAC and sends the pre-processing image data from the RAM 12 of the control unit 10 of the device main body to the PCI-PCI bus bridge 200. A read request is made (S201). Accordingly, the PCI-PCI bus bridge 200 sends a request signal (REQ #) for acquiring the right to use the primary PCI bus 61 to the bus arbitration unit 50 (S202). At the same time, the PCI-PCI bus bridge 200 executes the data transfer band setting process shown in FIG. 3 to set the data transfer band when reading the pre-processed image data from the RAM 12 of the control unit 10 of the apparatus main body ( S203).
Thereafter, the bus arbitration unit 50 arbitrates the request signal (REQ #) sent from each device including the PCI-PCI bus bridge 200 and then sends a bus use permission signal (to the PCI-PCI bus bridge 200). GNT #) is output. Thereby, the PCI-PCI bus bridge 200 acquires a bus use permission signal (GNT #) from the bus arbitration unit 50 (S204).

When the bus use permission signal (GNT #) is acquired from the bus arbitration unit 50, the transfer control unit 210 (see FIG. 2) of the PCI-PCI bus bridge 200 uses the data transfer band set in step 203 to Communication with the RAM 12 of the control unit 10 of the main body is performed (S205). Thereby, the control unit 110 of the image processing option device 100 reads the pre-processing image data from the RAM 12 of the control unit 10 of the apparatus main body, and sends the pre-processing image data to the image processing unit 120 (see FIG. 1) (S206).
Then, the image processing unit 120 executes predetermined image processing (for example, OCR processing) on the pre-processing image data, and generates post-processing image data (S207).

Next, the control unit 110 of the image processing option device 100 activates the DMAC and requests the PCI-PCI bus bridge 200 to write the processed image data to the RAM 12 of the control unit 10 of the apparatus body (S208). ). As a result, the PCI-PCI bus bridge 200 sends a request signal (REQ #) for acquiring the right to use the primary PCI bus 61 to the bus arbitration unit 50 (S209). At the same time, the PCI-PCI bus bridge 200 executes the data transfer band setting process of FIG. 3 described above, and sets the data transfer band for writing the processed image data to the RAM 12 of the control unit 10 of the apparatus main body ( S210).
Thereafter, the bus arbitration unit 50 arbitrates the request signal (REQ #) sent from each device including the PCI-PCI bus bridge 200 and then sends a bus use permission signal (to the PCI-PCI bus bridge 200). GNT #) is output. Thereby, the PCI-PCI bus bridge 200 acquires a bus use permission signal (GNT #) from the bus arbitration unit 50 (S211).

  When the bus use permission signal (GNT #) is acquired from the bus arbitration unit 50, the transfer control unit 210 of the PCI-PCI bus bridge 200 uses the data transfer band set in step 210, and the control unit 10 of the apparatus main body. Communication with the RAM 12 is performed (S212). Thereby, the control unit 110 of the image processing option device 100 writes the processed image data to the RAM 12 of the control unit 10 of the apparatus body (S213).

  As described above, in the image processing option apparatus 100 according to the present embodiment, when data is transmitted / received to / from the apparatus body, the data transfer band setting process shown in FIG. Set the data transfer bandwidth in. Then, data transfer is performed with the apparatus main body using the set data transfer bandwidth.

<Description of video data transfer status>
As described above, when data transmission / reception is performed between the image processing option device 100 and the apparatus main body, the PCI-PCI bus bridge 200 according to the present embodiment performs a primary operation according to the usage status of the primary PCI bus 61. The PCI bus 61 adjusts the transfer band of data transmitted and received between the image processing option apparatus 100 and the apparatus main body. As a result, in the primary PCI bus 61, for example, data transfer in a device such as the video I / F 25 that requires a guaranteed transfer band is prioritized, and transmission of video data to the video I / F 25 is interrupted. And the continuity of the video data is ensured. On the primary PCI bus 61, when a device such as a video I / F 25 that requires a guaranteed transfer band is not transferring data, data transfer between the image processing option device 100 and the device main body is performed. Is set corresponding to the data transfer capacity of the primary PCI bus 61, the primary PCI bus 61 is used effectively, and data transfer is performed efficiently.

FIG. 5 is a timing chart showing the transfer state of video data in this embodiment. As shown in FIG. 5, from a device such as the control unit 110 connected to the secondary PCI bus 164 of the image processing option device 100, for example, the RAM 12 in the control unit 10 connected to the primary PCI bus 61 of the apparatus main body. When the data transmission request (Read) to the device is performed ((A) in FIG. 5), the PCI-PCI bus bridge is transmitted by the data transmission request (Retry) several times ((B) in FIG. 5). 200 (PPB) acquires the right to use the bus on the primary PCI bus 61 from the bus arbitration unit 50. Thereby, the PCI-PCI bus bridge 200 (PPB) reads data (for example, video data) from the RAM 12 via the primary PCI bus 61 ((C) of FIG. 5). In this case, the PCI-PCI bus bridge 200 (PPB) uses the second data transfer band (for example, the data transfer band stored in the high-band burst length storage unit 272 by the data transfer band setting process in FIG. 3 described above. 64 burst length).
Then, the control unit 110 reads video data from the data storage unit 280 (see FIG. 2) of the PCI-PCI bus bridge 200 (PPB) via the secondary PCI bus 164 using the DMAC function ((D in FIG. 5). )).

  On the other hand, in the primary PCI bus 61, after the video data is read from the PCI-PCI bus bridge 200 (PPB), the bus arbitration unit 50 grants the bus right to use the primary PCI bus 61 to the video I / F 25. Suppose that Thereby, on the primary PCI bus 61, ASIC_B 72, which is a bus bridge to the video I / F 25, performs data transfer ((E) of FIG. 5). Thereby, the ASIC_B 72 performs a process of transferring the video data to the video I / F 25 via the secondary PCI bus 62 ((F) in FIG. 5).

After the right to use the bus on the primary PCI bus 61 is granted to the video I / F 25, the PCI-PCI bus bridge 200 (PPB) makes several data transmission requests (Retry) ((G) in FIG. 5). Suppose that the bus use right is acquired from the bus arbitration unit 50. Thereby, the PCI-PCI bus bridge 200 (PPB) reads, for example, video data from the RAM 12 via the primary PCI bus 61 ((H) in FIG. 5).
In this case, before the PCI-PCI bus bridge 200 (PPB) reads the video data, the PCI-PCI bus bridge 200 (PPB) sends a bus use notification signal (for the next device) output from the bus arbitration unit 50 ( FRAME #) is received ((I) in FIG. 5). Then, the PCI-PCI bus bridge 200 (PPB) executes the data transfer band setting process shown in FIG. That is, the address data included in the transfer data of the device to which the bus use right is granted in the primary PCI bus 61 is acquired with the reception of the bus use notification signal (FRAME #) as a trigger. The PCI-PCI bus bridge 200 (PPB) is, for example, the video I / F 25 in which the address data needs to guarantee the data transfer band on the primary PCI bus 61, and the measurement time acquired from the time measurement unit 250 is used. By determining that it is shorter than the determination reference time, the first data transfer band (for example, 16 clock bursts) stored in the low-band burst length storage unit 271 is set.
As a result, when the PCI-PCI bus bridge 200 (PPB) reads, for example, video data from the RAM 12 via the primary PCI bus 61 ((H) in FIG. 5), data transfer is performed with a burst length of 16 clocks. Then, the control unit 110 reads video data from the data storage unit 280 of the PCI-PCI bus bridge 200 (PPB) via the secondary PCI bus 164 using the DMAC function ((J) in FIG. 5).

  For example, reading of video data ((H) in FIG. 5) by the PCI-PCI bus bridge 200 (PPB) is performed with a first data transfer band (for example, a burst length of 16 clocks) and a low band. Therefore, the data transfer (K in FIG. 5) performed by the ASIC_B 72 that is a bus bridge to the video I / F 25 to which the next bus use right is granted is the data transfer (ASIC (B) in FIG. 5) performed last time. The interval from the end of)) can be shortened. Thereby, the process in which the ASIC_B 72 transfers the video data to the video I / F 25 via the secondary PCI bus 62 ((L) in FIG. 5) is changed to the process in which the previous video data is transferred ((F) in FIG. 5). It is done continuously. As a result, the occurrence of interruption in the video data transferred to the video I / F 25 is suppressed, and the occurrence of voids (image skipping) in the image formed by the image forming process in the image forming unit 35 is suppressed. It is done.

<Description of Video Data Transfer State in First Comparative Example>
Here, as a first comparative example, when data is transmitted / received between the image processing option apparatus 100 and the apparatus main body, the PCI-PCI bus bridge 200 is connected to the image processing option apparatus 100 and the apparatus main body on the primary PCI bus 61. A case will be described in which the transfer band of data transmitted / received to / from is constantly set high, for example, as a burst length of 64 clocks.

FIG. 6 is a timing diagram showing the video data transfer state when the transfer band of data transmitted and received between the image processing option apparatus 100 and the apparatus main body is always set to a fixed high value, for example, as a burst length of 64 clocks. It is a chart. As shown in FIG. 6, for example, the RAM 12 in the control unit 10 connected to the primary PCI bus 61 of the apparatus main body from a device such as the control unit 110 connected to the secondary PCI bus 164 of the image processing option device 100. When a data transmission request (Read) to the device is performed ((A) in FIG. 6), the PCI-PCI bus bridge is transmitted in response to the data transmission request (Retry) several times ((B) in FIG. 6). 200 (PPB) acquires the right to use the bus on the primary PCI bus 61 from the bus arbitration unit 50. Thereby, the PCI-PCI bus bridge 200 (PPB) reads data (for example, video data) from the RAM 12 via the primary PCI bus 61 ((C) in FIG. 6). In this case, the PCI-PCI bus bridge 200 (PPB) definitely sets the data transfer band to a burst length of 64 clocks.
Then, the control unit 110 reads video data from the data storage unit 280 (see FIG. 2) of the PCI-PCI bus bridge 200 (PPB) via the secondary PCI bus 164 using the DMAC function ((D in FIG. 6). )).

  On the other hand, in the primary PCI bus 61, after the video data is read from the PCI-PCI bus bridge 200 (PPB), the bus arbitration unit 50 grants the bus right to use the primary PCI bus 61 to the video I / F 25. Suppose that Thereby, on the primary PCI bus 61, ASIC_B 72, which is a bus bridge to the video I / F 25, performs data transfer ((E) of FIG. 6). Thereby, the ASIC_B 72 performs a process of transferring the video data to the video I / F 25 via the secondary PCI bus 62 ((F) in FIG. 6).

After the right to use the bus on the primary PCI bus 61 is granted to the video I / F 25, the PCI-PCI bus bridge 200 (PPB) makes several data transmission requests (Retry) ((G) in FIG. 6). Suppose that the bus use right is acquired from the bus arbitration unit 50. Thereby, the PCI-PCI bus bridge 200 (PPB) reads, for example, video data from the RAM 12 via the primary PCI bus 61 ((H) in FIG. 6).
In this case, the PCI-PCI bus bridge 200 (PPB) receives the bus use notification signal (FRAME #) for the next device output from the bus arbitration unit 50 ((I) in FIG. 5). However, in the PCI-PCI bus bridge 200 (PPB), the device to which the right to use the bus in the primary PCI bus 61 is given next needs to guarantee the data transfer band in the primary PCI bus 61, for example, video I / F 25 Even so, the data transfer bandwidth is definitely set to a burst length of 64 clocks.
As a result, when the PCI-PCI bus bridge 200 (PPB) reads, for example, video data from the RAM 12 via the primary PCI bus 61 ((H) in FIG. 6), data transfer is performed with a burst length of 64 clocks. Then, the control unit 110 reads video data from the data storage unit 280 of the PCI-PCI bus bridge 200 (PPB) via the secondary PCI bus 164 using the DMAC function ((J) in FIG. 6).

  For example, video data reading (H in FIG. 6) by the PCI-PCI bus bridge 200 (PPB) is performed with a burst length of 64 clocks and a high band. Therefore, the data transfer (K in FIG. 6) performed by the ASIC_B 72 that is a bus bridge to the video I / F 25 to which the next bus use right is granted is the data transfer (ASIC (B) in FIG. 6) performed last time. The interval from the end of)) becomes longer. Therefore, the process in which the ASIC_B 72 transfers the video data to the video I / F 25 via the secondary PCI bus 62 ((L) in FIG. 6) is the process for transferring the previous video data ((F) in FIG. 6). It will be performed discontinuously. As a result, the video data transferred to the video I / F 25 may be interrupted, and an image formed by the image forming process in the image forming unit 35 may be lost (image skipping).

<Description of Video Data Transfer State in Second Comparative Example>
Here, as a second comparative example, when data is transmitted / received between the image processing option apparatus 100 and the apparatus main body, the PCI-PCI bus bridge 200 is connected to the image processing option apparatus 100 and the apparatus main body on the primary PCI bus 61. A case will be described in which the transfer band of data transmitted / received to / from is constantly set low, for example, as a burst length of 16 clocks.

FIG. 7 is a timing diagram illustrating a transfer state of video data when the transfer band of data transmitted and received between the image processing option apparatus 100 and the apparatus main body is constantly set to a low value, for example, as a burst length of 16 clocks. It is a chart. As shown in FIG. 7, for example, a RAM 12 in the control unit 10 connected to the primary PCI bus 61 of the apparatus main body from a device such as the control unit 110 connected to the secondary PCI bus 164 of the image processing option device 100. When a data transmission request (Read) to the device is performed ((A) in FIG. 7), the PCI-PCI bus bridge is transmitted in response to the data transmission request (Retry) several times ((B) in FIG. 7). 200 (PPB) acquires the right to use the bus on the primary PCI bus 61 from the bus arbitration unit 50. Thereby, the PCI-PCI bus bridge 200 (PPB) reads data (for example, video data) from the RAM 12 via the primary PCI bus 61 ((C) in FIG. 7). In this case, the PCI-PCI bus bridge 200 (PPB) definitely sets the data transfer band to a burst length of 16 clocks.
Then, the control unit 110 reads video data from the data storage unit 280 (see FIG. 2) of the PCI-PCI bus bridge 200 (PPB) via the secondary PCI bus 164 using the DMAC function ((D in FIG. 7). )).

  On the other hand, in the primary PCI bus 61, after the video data is read from the PCI-PCI bus bridge 200 (PPB), the bus arbitration unit 50 grants the bus right to use the primary PCI bus 61 to the video I / F 25. Suppose that Thereby, on the primary PCI bus 61, ASIC_B 72, which is a bus bridge to the video I / F 25, performs data transfer ((E) of FIG. 7). Thereby, the ASIC_B 72 performs a process of transferring the video data to the video I / F 25 via the secondary PCI bus 62 ((F) in FIG. 7).

After the right to use the bus on the primary PCI bus 61 is granted to the video I / F 25, the PCI-PCI bus bridge 200 (PPB) makes several data transmission requests (Retry) ((G) in FIG. 7). Suppose that the bus use right is acquired from the bus arbitration unit 50. Thereby, the PCI-PCI bus bridge 200 (PPB) reads, for example, video data from the RAM 12 via the primary PCI bus 61 ((H) in FIG. 7).
In that case, the PCI-PCI bus bridge 200 (PPB) receives the bus use notification signal (FRAME #) for the next device output from the bus arbitration unit 50 ((I) in FIG. 7). However, in the PCI-PCI bus bridge 200 (PPB), for example, in the video I / F 25 in which the device to which the right to use the bus on the primary PCI bus 61 is granted next needs to guarantee the data transfer band on the primary PCI bus 61. Even if a long time has elapsed since the previous data transfer process (the state where the primary PCI bus 61 is free), the data transfer band is definitely set to a burst length of 16 clocks.
As a result, when the PCI-PCI bus bridge 200 (PPB) reads, for example, video data from the RAM 12 via the primary PCI bus 61 ((H) in FIG. 7), data transfer is performed with a burst length of 16 clocks. Then, the control unit 110 reads video data from the data storage unit 280 of the PCI-PCI bus bridge 200 (PPB) via the secondary PCI bus 164 using the DMAC function ((J) in FIG. 7).

  For example, video data reading ((H) in FIG. 7) by the PCI-PCI bus bridge 200 (PPB) is performed with a burst length of 16 clocks and a low band. Therefore, the data transfer ((K) in FIG. 7) performed by the device (Device) to which the next bus use right is granted is an interval from the end of the data transfer ((E) in FIG. 5) performed last time by ASIC_B72. Becomes longer. Therefore, from the time when the previous ASIC_B 72 performed data transfer on the primary PCI bus 61 ((E) in FIG. 7) until the device performs data transfer ((K) in FIG. 7), the primary PCI bus 61 has Free bandwidth increases. As a result, the data transfer capacity of the primary PCI bus 61 is not used effectively, and data transfer is performed at a low speed between the image processing option apparatus 100 and the apparatus main body, resulting in waste.

In contrast to the first comparative example and the second comparative example, the PCI-PCI bus bridge 200 according to the present embodiment performs data transmission / reception between the image processing option apparatus 100 and the apparatus main body. The transfer bandwidth of data transmitted / received between the image processing option device 100 and the apparatus main body on the primary PCI bus 61 is adjusted according to the usage status of the primary PCI bus 61.
As a result, on the primary PCI bus 61, for example, data transfer in a device such as the video I / F 25 that requires a guaranteed transfer band is prioritized. Therefore, interruption of transmission of video data to a device that requires a guaranteed transfer band is suppressed, and continuity of video data is ensured.
Further, it is not necessary to keep the data transfer rate of the function expansion device low in accordance with the video data transfer band set in the image forming apparatus 1.

  Next, FIG. 8 is a diagram showing a hardware configuration of the PCI-PCI bus bridge 200. As shown in FIG. 8, the PCI-PCI bus bridge 200 performs a digital operation process according to a predetermined program when performing data transfer control between the primary PCI bus 61 and the secondary PCI bus 164. CPU 201 as an example of means, RAM 202 used as a work area of CPU 201, ROM 203 storing data such as setting values used in programs executed by CPU 201, rewritable data even when power supply is interrupted And an interface (I / F) unit 205 that constitutes a PCI interface (PCI_I / F) 221 and a PCI interface (PCI_I / F) 222.

  Here, for example, a program executed by the PCI-PCI bus bridge 200 is stored in the external storage unit 150 arranged in the image processing option device 100, and the PCI-PCI bus bridge 200 reads this program, whereby Data transfer control is executed. That is, a program or the like for executing data transfer control is read into the RAM 202 of the PCI-PCI bus bridge 200 from, for example, a flash memory or the like as the external storage unit 150. Then, based on the program read into the RAM 202, the CPU 201 performs various processes. As another providing form regarding this program, there is a form in which the program is provided in a state stored in the ROM 203 in advance and loaded into the RAM 202. Further, when the rewritable ROM 203 such as an EEPROM is provided, there is a form in which only the program is installed in the ROM 203 and loaded into the RAM 202 after the image processing option device 100 is set. Further, there is a form in which a program is transmitted to the PCI-PCI bus bridge 200 via a network (not shown) such as the Internet, installed in the ROM 203 of the PCI-PCI bus bridge 200, and loaded into the RAM 202. Furthermore, there is a form in which the RAM 202 is loaded from an external recording medium such as a DVD-ROM or a flash memory.

As described above, in the image forming apparatus 1 according to the present embodiment, the PCI-PCI bus bridge 200 transmits and receives data between the image processing option apparatus 100 and the apparatus main body. The transfer bandwidth of data transmitted / received between the image processing option apparatus 100 and the apparatus main body is adjusted on the primary PCI bus 61 according to the use situation.
Thereby, on the primary PCI bus 61, priority is given to data transfer in a device such as the video I / F 25 that requires a guaranteed transfer band.

  Application examples of the present invention include application to image forming apparatuses such as copying machines and printers using an electrophotographic system to which a function expansion device such as an image processing board can be attached, and function expansion devices such as an image processing board Can be mounted and applied to a personal computer or the like that outputs image data to an image display unit or the like.

1 is a block diagram illustrating an example of the overall configuration of an image forming apparatus to which the exemplary embodiment is applied. It is a block diagram explaining the functional structure of a PCI-PCI bus bridge. It is the flowchart which showed the content of the determination process which a PCI-PCI bus bridge performs regarding the data transfer speed on a primary PCI bus. It is a flowchart which shows the processing content in the case of performing image processing to video data with an image processing option apparatus. 4 is a timing chart showing a transfer state of video data in the present embodiment. 6 is a timing chart showing a video data transfer state when a transfer band of data transmitted and received between the image processing option device and the apparatus main body is constantly set to a fixed high value, for example, as a burst length of 64 clocks. 10 is a timing chart showing a video data transfer state when a transfer band of data transmitted and received between the image processing option device and the apparatus main body is always set to a fixed low value, for example, as a burst length of 16 clocks. It is the figure which showed the hardware constitutions of the PCI-PCI bus bridge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 10, 110 ... Control part, 25 ... Video interface (I / F), 35 ... Image forming part, 50, 130 ... Bus arbitration part, 61 ... Primary PCI bus, 71 ... ASIC_A, 72 ... ASIC_B , 120 ... Image processing unit, 164 ... Secondary PCI bus, 200 ... PCI-PCI bus bridge, 210 ... Transfer control unit, 221 and 222 ... PCI interface (PCI_I / F), 230 ... Determination unit, 240 ... Address information storage unit , 250 ... Time measuring section, 260 ... Determination condition storage section, 271 ... Low band burst length storage section, 272 ... High band burst length storage section, 280 ... Data storage section

Claims (11)

A first data transfer path for transferring data;
A second data transfer path for transferring data and connected to the first data transfer path;
A transfer condition for transferring data using the first data transfer path and the second data transfer path is required for the device making a use request for the first data transfer path. And a setting means for setting based on the transfer rate. Arrangement means for arbitrating use permission / non-permission of the first data transfer path for the device making a use request to the first data transfer path,
The setting means sets, based on the transfer speed, a data amount to be transferred at one use permission given from the arbitration means as the transfer condition or a time for occupying the first data transfer path. The control device according to claim 1, wherein: Arrangement means for arbitrating use permission / non-permission of the first data transfer path for the device making a use request to the first data transfer path,
The setting unit monitors a transfer rate required for the device based on the use permission from the arbitration unit, and sets the transfer condition according to the transfer rate in the device to which the use permission is granted. The control device according to claim 1.   The said setting means sets the said transfer condition in consideration of the elapsed time after the said last use permission was sent to the said device in the said device to which the said use permission was given. Control device. Arrangement means for arbitrating use permission / non-permission of the first data transfer path for the device making a use request to the first data transfer path,
The setting unit holds a plurality of the transfer conditions that are different from each other in the amount of data transferred from the arbitration unit, and sets any one of the plurality of transfer conditions. The control device according to claim 1. Image forming means for forming an image based on image data;
A first data transfer path to which the image forming means is connected and transfers the image data;
A second data transfer path that transfers the image data and is connected to the first data transfer path;
The image formation in which the transfer condition for transferring the image data using the first data transfer path and the second data transfer path is used as a request for use of the first data transfer path. An image forming apparatus comprising: setting means for setting based on a transfer speed required for the means.   The setting means transfers the amount of image data transferred at one use permission given from the arbitration means for arbitrating use permission / non-permission of the first data transfer path to the image forming means, or the first 7. The image forming apparatus according to claim 6, wherein a time for occupying a data transfer path is set as the transfer condition.   The setting unit monitors a transfer speed required for the image forming unit based on a use permission from an arbitration unit that arbitrates use permission / non-permission of the first data transfer path with respect to the image forming unit. The image forming apparatus according to claim 6, wherein the transfer condition is set according to a transfer speed required for the image forming unit to which the use permission is given.   The setting unit sets the transfer condition in consideration of an elapsed time since the previous use permission is sent to the image forming unit in the image forming unit to which the use permission is given. The image forming apparatus according to claim 8.   The setting means includes a plurality of the image data amounts to be transferred in one use permission given from the arbitration means that arbitrates use permission / non-permission of the first data transfer path to the image forming means. 7. The image forming apparatus according to claim 6, wherein a transfer condition is held, and any one of the plurality of transfer conditions is set. On the computer,
A function for monitoring a transfer rate required for a device making a use request to the first data transfer path through which data is transferred;
When transferring data using the first data transfer path and the second data transfer path connected to the first data transfer path, transfer conditions for transferring the data are set as the device A program for realizing a function for setting based on a transfer rate required for the computer.

Images