JP2013097420A - Information processing apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information processing apparatus that automatically releases lock of a bus to improve convenience of a user.SOLUTION: In an information processing apparatus, after any device of a plurality of devices issued a processing request to another device, if a bus control unit 140 detects lock of a bus 1 caused by absence of transmission of a completion signal indicating completion of processing to the bus 1 from the device that has issued the processing request or the device that has received the processing request, transmits a completion signal to the bus 1 by proxy.

Description

  The present invention relates to an information processing apparatus and an image forming apparatus.

  2. Description of the Related Art Conventionally, various apparatuses including an information processing apparatus (for example, an image forming apparatus) employ a control system in which a device that makes a processing request and a device that receives the processing request are connected to each other via a bus. For example, a device that makes a processing request is called a bus master, and a device that receives a processing request is called a bus slave.

  In such an information processing apparatus, a processing request is transmitted from the bus master to the bus slave, and the bus slave performs a request processing from the bus master. For this reason, if an abnormality occurs in the bus master, an appropriate processing request is not transmitted to the bus slave, and the mechanism controlled by the bus slave may malfunction.

  Therefore, conventionally, when an abnormality occurs in the bus master, a technique for causing the bus slave to detect the abnormality of the bus master and resetting a control signal from the bus slave to the mechanism unit has been proposed (for example, Patent Documents). 1). In this way, the mechanism unit controlled by the bus slave stops without malfunctioning, so that it is possible to suppress the occurrence of inconvenience due to malfunction of the mechanism unit.

Japanese Patent Laid-Open No. 2001-154928

  Incidentally, in Patent Document 1, a plurality of bus masters and bus slaves are connected to the same bus. In this configuration, normally, a bus master other than the predetermined bus master cannot use the bus while the predetermined bus master is using the bus. Therefore, for example, when an abnormality occurs in a predetermined bus master while the predetermined bus master is using the bus, the bus is continuously used by the predetermined bus master, and until the state is resolved, A bus master other than the predetermined bus master cannot use the bus (the bus is locked). For this reason, it is necessary for the user to perform an operation for releasing the lock of the bus (for example, an operation for restarting the entire apparatus). As a result, it is not convenient for the user.

  The present invention has been made to solve the above problems, and provides an information processing apparatus and an image forming apparatus capable of improving user convenience by automatically unlocking a bus. For the purpose.

  In order to achieve the above object, an information processing apparatus according to the present invention includes a bus that is a data transmission path, a plurality of devices that transmit and receive data via the bus, and whether or not the bus is locked. A bus control unit for detection. Then, after one of the plurality of devices makes a processing request to the other device, the bus control unit indicates completion of processing from the processing request source device or the processing request destination device to the bus. When the lock of the bus due to the absence of signal transmission is detected, the bus lock is released by transmitting a completion signal to the bus by proxy.

  Here, after one of a plurality of devices makes a processing request to another device, normally, a completion signal is transmitted to the bus from the processing request source device or the processing request destination device. Until the request is made, the requesting device continues to use the bus. Accordingly, when the completion signal is not transmitted from the process request source device or the process request destination device to the bus, the use of the bus by the process request source device is continued and the bus is locked. For this reason, a device other than the device that caused the bus lock cannot be used. In this case, the user must perform some operation such as restarting the entire apparatus, which is not convenient.

  Therefore, in the information processing apparatus of the present invention, the bus control unit detects a lock of the bus caused by no transmission of a completion signal indicating completion of processing to the bus from the processing request source device or the processing request destination device. When this is done, a completion signal is transmitted to the bus as a proxy. For this reason, the use of the bus by the processing request source device can be ended, and the lock of the bus is automatically released. This eliminates the need for the user to perform an operation for unlocking the bus, thus improving user convenience.

  In the above configuration, the bus control unit preferably prevents the device that caused the lock of the bus from accessing the bus after transmitting the completion signal to the bus by proxy. Here, if the device that previously caused the lock of the bus accesses the bus again and makes a processing request, the bus may be locked in the same manner as before.

  However, in the information processing apparatus of the present invention, the bus control unit does not allow the device that caused the lock of the bus to access the bus. For this reason, it is possible to prevent the bus from being locked in the same manner as before.

  In the above configuration, more preferably, the device further includes a switch unit for accessing the bus, and the bus control unit transmits a completion signal to the bus on behalf of the device, and then causes the device that caused the bus lock to occur. Let the switch block the connection with the bus. With this configuration, it is possible to easily prevent the device that caused the bus lock from accessing the bus.

  In the above configuration, the bus control unit preferably resets only the device that caused the lock of the bus. With this configuration, when an abnormality has occurred in the device that has caused the lock of the bus, the device can be easily restored from the abnormal state.

  An image forming apparatus of the present invention includes the above information processing apparatus. In the image forming apparatus configured as described above, the bus can be automatically unlocked, thereby improving the convenience for the user.

  As described above, according to the present invention, it is possible to easily obtain an information processing apparatus and an image forming apparatus that can improve user convenience by automatically unlocking a bus.

1 is an overall configuration diagram of an image forming apparatus including an information processing apparatus according to an embodiment of the present invention. The block diagram which showed the hardware constitutions of the information processing apparatus by one Embodiment of this invention The figure for demonstrating the function of the bus control part contained in the information processing apparatus by one Embodiment of this invention The flowchart for demonstrating operation | movement (operation | movement when releasing the lock | rock of a bus) of the information processing apparatus by one Embodiment of this invention.

  The overall configuration of the image forming apparatus 100 including the information processing apparatus 150 according to an embodiment of the present invention will be described below with reference to FIG.

  The image forming apparatus 100 according to the present embodiment is a multifunction machine capable of executing a plurality of types of jobs such as a copy, a printer, a scanner, and a fax machine. The image forming apparatus 100 includes an operation panel 101, an image reading unit 102, a paper feeding unit 103, a conveyance path 104, an image forming unit 105, a fixing unit 106, and the like. In the following description, the mechanism unit including the paper feeding unit 103, the conveyance path 104, the image forming unit 105, and the fixing unit 106 may be referred to as an engine unit 107.

  The operation panel 101 includes a liquid crystal display unit 11 whose display surface is covered with a touch panel. The liquid crystal display unit 11 displays a menu for performing various settings and setting keys (soft keys), and also displays a message indicating the device status and the like. The operation panel 101 is also provided with a numeric keypad 12 for accepting setting instructions that require numerical input, a start key 13 for accepting instructions for starting execution of various jobs, and the like.

  The image reading unit 102 reads a document and generates image data of the document. Although not shown, the image reading unit 102 is provided with optical system members such as an exposure lamp, a mirror, a lens, and an image sensor. Then, when reading the document placed on the placement reading contact glass 21, the image reading unit 102 irradiates the document with the light of the exposure lamp and A / D converts the output value of the image sensor that receives the reflected light. After that, image data is generated by performing various corrections (such as shading correction) on the data after A / D conversion. Thus, printing can be performed based on the image data obtained by the original reading operation by the image reading unit 102. In addition, image data obtained by a document reading operation by the image reading unit 102 can be accumulated.

  The image reading unit 102 is provided with a document cover 22. When the original is read by the placement reading contact glass 21, the original placed on the placement reading contact glass 21 can be pressed by the original cover 22. The document cover 22 may have a function as a document conveying device. In this case, the manuscript cover 22 can feed manuscripts one by one to the feed reading contact glass 23.

  The paper feed unit 103 has a plurality of cassettes 31 for storing paper P, and supplies the paper P stored in the plurality of cassettes 31 to the conveyance path 104. The paper feed unit 103 is provided with a pickup roller 32 that pulls out the stored paper P, a separation roller pair 33 for suppressing double feeding of the paper P, and the like.

  The conveyance path 104 conveys the paper P inside the apparatus. More specifically, the paper P supplied from the paper supply unit 103 passes through the image forming unit 105 and the fixing unit 106 in this order by the conveyance path 104 and is guided to the discharge tray 41. A plurality of transport roller pairs 42 that transport the paper P are provided in the transport path 104. Further, a registration roller pair 43 is also provided that waits for the paper P in front of the image forming unit 105 and sends the paper P to the image forming unit 105 in time.

  The image forming unit 105 forms a toner image based on the image data, and transfers the toner image onto the paper P. The image forming unit 105 includes a photosensitive drum 51, a charging device 52, an exposure device 53, a developing device 54, a transfer roller 55, a cleaning device 56, and the like.

  In the toner image formation process and the toner image transfer process to the paper P, first, the photosensitive drum 51 is rotationally driven, and the surface of the photosensitive drum 51 is charged to a predetermined potential by the charging device 52. The exposure device 53 outputs a light beam L based on the image data, and scans and exposes the surface of the photosensitive drum 51. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 51. Subsequently, the developing device 54 supplies toner to the electrostatic latent image formed on the surface of the photosensitive drum 51 and develops it.

  The transfer roller 55 is in pressure contact with the surface of the photosensitive drum 51. Thereafter, the registration roller pair 43 measures the timing and causes the paper P to enter between the transfer roller 55 and the photosensitive drum 51. At this time, a predetermined voltage is applied to the transfer roller 55. As a result, the toner image on the surface of the photosensitive drum 51 is transferred to the paper P. When the transfer process is finished, the cleaning device 56 removes the toner remaining on the surface of the photosensitive drum 51.

  The fixing unit 106 heats and presses the toner image transferred onto the paper P to fix it. The fixing unit 106 includes a fixing roller 61 having a built-in heat source, and a pressure roller 62 that is pressed against the fixing roller 61. The paper P on which the toner image is transferred is heated and pressed by passing between the fixing roller 61 and the pressure roller 62. As a result, the toner image is fixed on the paper P and printing is completed. The printed paper P is guided to the transport path 104 and is sent to the discharge tray 41 by the transport roller pair 42.

  Next, the hardware configuration of the image forming apparatus 100 will be described with reference to FIG.

  The main control unit 110 controls the entire apparatus of the image forming apparatus 100. The main control unit 110 includes a CPU 111 that is a central processing unit. The main control unit 110 (CPU 111) is connected to the storage unit 112 via the bus 1. The storage unit 112 includes a ROM 112a, a RAM 112b, an HDD 112c, and the like. Note that the main control unit 110 may be provided with a storage unit 112.

  The main control unit 110 is connected to the operation panel 101, the image reading unit 102, and the engine unit 107 (the paper feeding unit 103, the conveyance path 104, the image forming unit 105, and the fixing unit 106) via the bus 1. Thereby, the main control unit 110 performs overall control, calculation, and the like based on various programs and data stored in the storage unit 112.

  The operation panel 101 includes a display control unit 101a composed of a CPU or the like, and the display control unit 101a performs display control of the operation panel 101. The image reading unit 102 includes a reading control unit 102a including a CPU, and the reading control unit 102a performs reading control of the image reading unit 102. The engine unit 107 includes an engine control unit 107a including a CPU or the like, and the engine control unit 107a performs control of the engine unit 107 (for example, on / off control of a motor that rotates various rotating bodies).

  The main control unit 110 is connected to the image processing unit 120 via the bus 1. The image processing unit 120 is composed of, for example, an ASIC or memory dedicated to image processing. Then, the image processing unit 120 performs various image processing such as density conversion processing, enlargement / reduction processing, rotation processing, and compression / expansion processing on the image data. Note that the image processing unit 120 may be divided into, for example, a plurality of blocks (in this embodiment, an example in which the image processing unit 120 is divided into two, the first image processing unit 121 and the second image processing unit 122). ). In this case, only one of the first image processing unit 121 and the second image processing unit 122 may perform image processing, or the first image processing unit 121 and the second image processing unit 122. Both may perform image processing.

  Further, the main control unit 110 is connected to the communication unit 130 via the bus 1. The communication unit 130 is connected to the external computer 200 via a network (or a communication cable), for example, so that communication is possible. Thereby, printing can be performed based on the image data transmitted from the computer 200. In addition, image data obtained by a document reading operation by the image reading unit 102 can be transmitted to the computer 200. Further, for example, a modem or the like may be built in the communication unit 130. In this case, fax communication with the external fax machine 300 can be performed via a network such as a telephone line.

  Thus, in this embodiment, a plurality of devices are connected to the common bus 1, and data communication between the plurality of devices is performed via the common bus 1. In this embodiment, the storage unit 112, the display control unit 101a, the reading control unit 102a, the engine control unit 107a, the image processing unit 120, the communication unit 130, and the like correspond to devices, and a bus system including these devices. Corresponds to the information processing apparatus 150. Each device of the information processing apparatus 150 can be a bus master (a device that makes a processing request) or a bus slave (a device that receives a processing request).

  By the way, in the information processing apparatus 150 in which a plurality of bus masters are connected to the common bus 1, the plurality of bus masters cannot use the bus 1 at the same time. Therefore, the information processing apparatus 150 is provided with a bus control unit 140 for arbitrating use of the bus 1 of each bus master. Note that the main control unit 110 may have the function of the bus control unit 140.

  For example, a bus master attempting to access a bus slave transmits a signal requesting permission to use the bus 1 to the bus control unit 140 when accessing the bus slave. The bus control unit 140 determines whether or not the bus 1 is currently used. If the bus 1 is not used, the bus control unit 140 grants the use permission of the bus 1 to the bus master that has requested the use permission of the bus 1. Returns the signal.

  Note that there may be a request for permission to use the bus 1 from two or more bus masters, thereby competing requests for permission to use the bus 1. For this reason, for example, a priority order regarding the use of the bus 1 is set in the plurality of bus masters. When two or more bus masters request permission for use of the bus 1 at the same time, the bus control unit 140 becomes a bus master having a higher priority among the two or more bus masters that have requested permission to use the bus 1. A signal to give permission to use the bus 1 is transmitted preferentially.

  As a result, the bus master granted the use permission of the bus 1 from the bus control unit 140 can use the bus 1. The bus control unit 140 does not grant other bus masters permission to use the bus 1 while the bus master who has given permission to use the bus 1 is using the bus 1. In other words, a bus master other than the bus master to which use permission of the bus 1 is granted cannot use the bus 1.

  The bus master granted the use permission of the bus 1 from the bus control unit 140 requests some processing from the bus slave. For example, when the bus master is the image processing unit 120 and the bus slave is the storage unit 112, the image processing unit 120 requests the storage unit 112 to write or read image data. When the processing is completed, the bus master or the bus slave transmits a completion signal indicating the processing completion to the bus 1.

  Here, for example, if any abnormality occurs in any of a pair of devices (bus master and bus slave) using the bus 1, even if processing requests are transmitted and received between the pair of devices. In some cases, the processing is not performed and the completion signal is not transmitted to the bus 1. In such a case, even if the bus 1 remains in use and another device requests the bus control unit 140 to use the bus 1, the other device cannot obtain the right to use the bus 1. (Bus 1 cannot be used). That is, the bus 1 is maintained in a locked state. When the bus 1 is locked, the image forming apparatus 100 must be restarted, which is inconvenient for the user.

  In order to eliminate such an inconvenience, the bus control unit 140 according to the present embodiment allows the processing request source device or the processing request destination after any of the plurality of devices makes a processing request to another device. It is detected whether or not the bus 1 is locked due to the absence of transmission of a completion signal indicating completion of processing from the device to the bus 1. When the bus control unit 140 detects the lock of the bus 1, the bus control unit 140 releases the lock of the bus 1 by transmitting a completion signal to the bus 1 by proxy.

  Specifically, as shown in FIG. 3, the bus control unit 140 includes a lock detection circuit 141 and a proxy response circuit 142. Note that the lock detection circuit 141 and the proxy response circuit 142 may be provided separately from the bus control unit 140.

  The lock detection circuit 141 is a circuit for detecting that the bus 1 is locked. For example, the lock detection circuit 141 determines that the bus 1 is locked if a completion signal is not transmitted to the bus 1 within a predetermined time after the processing request is transmitted and received between the pair of devices. Alternatively, the lock detection circuit 141 determines that the bus 1 is locked if processing is not performed within a predetermined time after the processing request is transmitted and received between the pair of devices. Note that the time used as a determination criterion when detecting the lock of the bus 1 may be set to a time that is practically impossible. When detecting the lock of the bus 1, the lock detection circuit 141 notifies the proxy response circuit 142 of the detection result.

  When the proxy response circuit 142 is notified from the lock detection circuit 141 that the bus 1 is locked, the proxy response circuit 142 transmits a completion signal to the bus 1 by proxy. As a result, the communication between the pair of devices via the bus 1 is completed, so that the bus 1 is released.

  However, if the device that previously caused the lock of the bus 1 accesses the bus 1 again after the bus 1 is opened, there is a high possibility that the bus 1 will be locked. Therefore, the bus control unit 140 according to the present embodiment prevents the device that caused the lock of the bus 1 from accessing the bus 1 after transmitting the completion signal to the bus 1 by proxy. .

  Specifically, a switch unit 2 (for example, a part including a transistor) is connected between the device and the bus 1 so that the bus control unit 140 controls on / off of the switch unit 2. It has become. Then, the bus control unit 140 transmits a completion signal to the bus 1 by proxy, and then causes the switch unit 2 to shut off the device that caused the lock of the bus 1 and the bus 1.

  Furthermore, the bus control unit 140 resets the bus 1 by transmitting a reset signal only to the device that has caused the lock of the bus 1. As a result, if an abnormality has occurred in the device that has caused the lock of the bus 1, the device may recover from the abnormal state. At this time, for example, the bus control unit 140 resets the device causing the lock of the bus 1 after blocking the bus 1 from the device causing the lock of the bus 1. Thereafter, the bus control unit 140 causes the switch unit 2 to perform connection between the reset device and the bus 1. As a result, the device that previously caused the lock of the bus 1 can access the bus 1 again.

  Although not shown, a reset circuit may be provided between a power source (not shown) and the device, and reset may be performed by shutting off the power supply to the device that caused the lock of the bus 1. .

  Next, with reference to FIG. 4, an operation from when the bus 1 is locked until the bus control unit 140 unlocks the bus 1 will be described.

  First, at the start of the flow of FIG. 4, for example, the right to use the bus 1 is assigned to the first image processing unit 121 (processing request source device, bus master), and the first image processing unit 121 is stored in the storage unit 112. A processing request is being sent to the processing request destination device (bus slave). Then, when the first image processing unit 121 makes a processing request to the storage unit 112, the flow of FIG. 4 starts.

  In step S1, the bus control unit 140 (lock detection circuit 141) indicates a processing request signal indicating that the first image processing unit 121 (processing request source device) has requested processing to the storage unit 112 (processing request destination device). Receive.

  In step S2, the bus control unit 140 (lock detection circuit 141) detects whether or not the bus 1 is locked. If the bus 1 is not locked, the process proceeds to step S3, and the bus control unit 140 determines between the first image processing unit 121 (processing request source device) and the storage unit 112 (processing request destination device). Continue processing performed in. On the other hand, if the bus 1 is locked, the process proceeds to step S4. Note that the fact that the bus 1 is locked is highly likely that an abnormality has occurred in the first image processing unit 121.

  In step S4, the bus control unit 140 (proxy response circuit 142) transmits a completion signal to the bus 1 by proxy. As a result, the lock of the bus 1 is released.

  In step S <b> 5, the bus control unit 140 causes the switch unit 2 to disconnect the connection between the first image processing unit 121 (processing request source device) and the bus 1. For this reason, the first image processing unit 121 cannot access the bus 1. However, devices other than the first image processing unit 121 (for example, the second image processing unit 122) can access the bus 1. Therefore, in this case, for example, if the subsequent image processing is performed only by the second image processing unit 122, there is no need to interrupt the job.

  In step S6, the bus control unit 140 resets only the first image processing unit 121 (processing request source device). If it does in this way, the 1st image processing part 121 may return from an abnormal state.

  In step S <b> 7, the bus control unit 140 causes the switch unit 2 to connect the reset first image processing unit 121 (reset device) and the bus 1. As a result, the first image processing unit 121 can access the bus 1. If the first image processing unit 121 returns from the abnormal state in the operation of step S6, the bus 1 will not be locked when the first image processing unit 121 performs processing next time.

  In the present embodiment, as described above, the bus control unit 140 receives a processing request from one of a plurality of devices to another device, and then from the processing request source device or the processing request destination device. When the lock of the bus 1 due to the absence of the transmission of the completion signal indicating the completion of processing to the bus 1 is detected, the completion signal is transmitted to the bus 1 by proxy.

  Here, after any one of the plurality of devices makes a processing request to another device, a completion signal is normally sent to the bus 1 from the processing request source device or the processing request destination device. The device requesting processing continues to use the bus until it is transmitted. Accordingly, when no completion signal is transmitted from the process request source device or the process request destination device to the bus 1, the use of the bus 1 by the process request source device is continued and the bus 1 is locked. Become. For this reason, a device other than the device that caused the bus 1 to be locked cannot use the bus 1. In this case, the user must perform some operation such as restarting the entire apparatus, which is not convenient.

  Therefore, in this embodiment, the bus control unit 140 detects the lock of the bus 1 due to the absence of transmission of a completion signal indicating completion of processing from the processing request source device or the processing request destination device to the bus 1. Then, a completion signal is transmitted to the bus 1 by proxy. For this reason, the use of the bus 1 by the processing request source device can be terminated, and the lock of the bus 1 is automatically released. This eliminates the need for the user to perform an operation for unlocking the bus 1, thereby improving user convenience.

  In the present embodiment, as described above, the bus control unit 140 transmits a completion signal to the bus 1 by proxy, and then accesses the device that caused the lock of the bus 1 to access the bus 1. Don't do it. Here, if a device that has previously caused the lock of the bus 1 accesses the bus 1 again and makes a processing request, the bus 1 may be locked in the same manner as before.

  However, in the present embodiment, the bus control unit 140 does not allow the device that caused the lock of the bus 1 to access the bus 1. For this reason, it can suppress that the bus | bath 1 locks similarly to before.

  In the present embodiment, as described above, the bus control unit 140 transmits a completion signal to the bus 1 by proxy, and then connects the device that has caused the lock of the bus 1 to the bus 1. The switch unit 2 is shut off. With this configuration, it is possible to easily prevent the device that caused the lock of the bus 1 from accessing the bus 1.

  In the present embodiment, as described above, only the device that caused the lock of the bus 1 is reset. According to this configuration, when an abnormality has occurred in the device that has caused the lock of the bus 1, the device can be easily restored from the abnormal state.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown not by the description of the above-described embodiment but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Bus 2 Switch part 100 Image forming apparatus 140 Bus control part 150 Information processing apparatus

Claims (5)

A bus that is a data transmission path;
A plurality of devices transmitting and receiving data via the bus;
A bus control unit that detects whether or not the bus is locked,
The bus control unit indicates completion of processing from the processing request source device or the processing request destination device to the bus after any one of the plurality of devices makes a processing request to another device. When detecting the lock of the bus due to the absence of transmission of a completion signal, the information processing apparatus releases the lock of the bus by transmitting the completion signal to the bus as a proxy .   2. The bus control unit according to claim 1, wherein after the completion signal is transmitted to the bus as a proxy, the device that causes the lock of the bus is not allowed to access the bus. The information processing apparatus described in 1. A switch unit for accessing the bus;
The bus control unit, after transmitting the completion signal to the bus as a proxy, causes the switch unit to cut off the connection between the device causing the lock of the bus and the bus. The information processing apparatus according to claim 2.   The information processing apparatus according to claim 2, wherein the bus control unit resets only a device that causes the bus to be locked.   An image forming apparatus comprising the information processing apparatus according to claim 1.

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