JP3814205B2 - Data transmission / reception system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to data transmission and reception system, in particular, a digital copying power supply system in the image forming system in which a separate digital copying machine which is provided with a bit map image data input-output device is configured by connecting to each BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission / reception system that transmits and receives data between a computer and a bitmap image data input / output device .
[0002]
[Prior art]
In recent years, as the functions of copying machines have advanced, copying machines themselves have been configured by connecting a plurality of devices. For example, a digital copier has a printer controller that develops image data for printing from a host into a bitmap on a main unit having a copy function, and compresses the read bitmap data into a standard format and converts it into a host as a file. The main body device inputs / outputs image data to / from an external device such as a host via the above-described controller. Large digital copiers capable of handling large-area paper such as A0 are required to transfer data to and from the controller at high speed due to an increase in the amount of image data due to bitmap data. In addition, with the recent improvement in the performance of personal computers, there is one that realizes the functions of the two types of controllers described above with a single personal computer. In such a case, the main body device of the digital copying machine and the controller can be installed far apart from each other.
[0003]
In such a case, each device operates with an independent power source, and signals between each other are cable-connected via an interface element such as LVDS (Low Voltage Differential Signaling). For example, a technique described in Japanese Patent Application Laid-Open No. 8-214138 is known as a related art relating to an image forming system configured by connecting a main body of a digital copying machine that operates with an independent power source and a controller. ing. In this prior art, the inactivity of the counterpart device is determined by detecting a break on the serial communication data line.
[0004]
[Problems to be solved by the invention]
The method according to the prior art described above is a device in which, when one of the devices is turned off, the device is in a no-communication state, and the other device that is turned on cannot detect a break and becomes inactive. On the other hand, there is a problem in that the normal operation is continued and the state falls into an abnormal state or a function stop state, the power is turned off / on, the power is turned on again, or a manual recovery operation is required.
[0005]
If one of the devices is a personal computer or the like, it takes a long time to start up the general-purpose OS and dedicated software, and the recovery operation is complicated. The controller and the copier itself are installed far apart. In such a case, it is difficult to restart both of them easily.
[0006]
The object of the present invention is to solve the above-mentioned problems of the prior art, and even if the power of one device is turned off, the device with the other power turned on detects a break in the serial communication data line. The main unit having a copy function that operates with an independent power source and a controller are connected to each other, so that recovery work such as restarting caused by turning off the power can be made unnecessary. An object of the present invention is to provide a data transmission / reception system that transmits and receives data between a main body apparatus having a copying function and a controller in the image forming system configured.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a data transmission / reception system in which a first device and a second device , each having an independent power source, are connected by a cable and transmit / receive data. In the system , the first device and the second device have their own devices turned off at terminals that control the output signal level of the other receiver through resistors pulled up to the respective power sources. When a signal indicating that the power of the counterpart device is turned off is applied to the terminal, all the output signals are connected to a level indicating a serial communication break state. It is characterized by having the following functions .
[0008]
According to a second aspect of the present invention, in the first aspect, when the signal line cable connecting the first device and the second device is disconnected, the receiver outputs the entire output signal. Has a function of setting a level indicating a break state of serial communication .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an image forming system according to the present invention will be described below in detail with reference to the drawings.
[0013]
FIG. 1 is a block diagram showing a configuration of an image forming system according to an embodiment of the present invention. In FIG. 1, 10 is a digital copying machine, 11 and 21 are receivers, 12 and 22 are transmitters, 13 and 23 are UARTs, 20 is a controller, and 30 is a cable.
[0014]
In an image forming system according to an embodiment of the present invention, a cable 30 includes a digital copier 10 configured to include a receiver 11, a transmitter 12, and a UART 13, and a controller 20 configured to include a receiver 21, a transmitter 22, and a UART 23. Are connected to each other. The controller 20 is a printer controller that develops image data for printing from a host configured in a personal computer or the like into a bitmap, and compresses the read bitmap data into a standard format, and sends it to the host as a file. It may be a bitmap image data input / output device configured with a scanner controller, or may be one of the aforementioned controllers. The digital copying machine 10 and the controller 20 are each configured with an independent power source (not shown). Further, an external device such as a host is connected to the controller 20 so that image data can be transmitted and received mutually.
[0015]
The cable 30 that connects the digital copying machine 10 and the controller 20 includes data lines 31 and 34 that send image information from the transmitters 12 and 22 of both apparatuses to the receivers 21 and 11 of the partner apparatus, and digital copying from the transmitter 22 of the controller 20. A command line 32 for sending a command to the receiver 11 of the machine 10, a signal line 35 for sending a status signal from the transmitter 12 of the digital copying machine 10 to the receiver 21 of the controller 20, and a ground line 37. Including signal lines 33 and 36 for sending a power-down signal to the power-down control terminal (PWRDWN) of the receivers 11 and 21 of the counterpart device through resistors pulled up to the respective power sources of both devices It is out.
[0016]
In the foregoing, the receivers 11 and 21 continue normal operation when the applied voltage at their power-down control terminals is at a high (H) level, and when the applied voltage is at a low (L) level, It has an inactive state and a function of setting all output signals to L level. When the power supplies of the devices 10 and 20 are operating normally, the power-down control terminal (PWRDWN) of the receivers 11 and 21 receives the pull-up resistor and power-down control as the power supply voltage of the counterpart device pulled up. The H level voltage divided by the resistor connected to the terminal is applied, and the receivers 11 and 21 can continue to operate normally.
[0017]
Now, it is assumed that the power of one device, for example, the controller 20 is turned off. At this time, the pulled-up voltage from the controller 20 disappears, and the power-down control terminal of the receiver 11 of the digital copying machine 10 is connected to the ground via a resistor connected between this terminal and the ground. A potential, that is, an L-level potential is applied. As a result, the receiver 11 becomes inactive, and all output signals are set to L level.
[0018]
The UART 13 connected to the receiver 11 and the transmitter 12 has a function of converting a parallel signal into a serial signal, or conversely, converting the serial signal into a parallel signal. Then, it is detected that all output signals from the receiver 11 have become L level. As a result, the UART 13 can detect the break state of the signal on the output side corresponding to the input side to which the serial communication data signal is connected, that is, the state of the brane section on the serial signal data line. In this case, it can be detected that the controller 20 is turned off and inactive.
[0019]
As described above, since the digital copying machine 10 can know the power-off of the controller 20 of the counterpart device, it turns off the power of its own device and tries to continue normal operation with respect to the controller 20. It is possible to eliminate an extra operation such as re-raising or manually performing a recovery operation.
[0020]
In the above description, it has been described that the power-off of the controller 20 on the digital copying machine 10 side when the power of the controller 20 is turned off is detected. However, when the power of the digital copying machine 10 is turned off, the controller 20 The power OFF of the digital copying machine 10 can be detected in exactly the same manner as described above.
[0021]
Further, in the embodiment of the present invention described above, even when the cable 30 connecting the digital copying machine 10 and the controller 20 is disconnected, the disconnection of the cable 30 can be detected in the same manner as described above. That is, when the cable 30 is disconnected, the power down control terminals of the receivers 11 and 21 of both the digital copying machine 10 and the controller 20 are connected to the ground potential via a resistor connected between the terminal and the ground. That is, an L level potential is applied. As a result, the receivers 11 and 21 are inactivated and all output signals are set to the L level.
[0022]
Therefore, when the cable is disconnected, the digital copying machine 10 and the controller 20 recognize that the other party's power source is turned off, and the power source of their own device is turned on as in the case described above. It is possible to eliminate the need for extra operations such as turning off / on and restarting or manually performing a recovery operation.
[0023]
According to an embodiment of the present invention described above, in the data transmission and reception system in which the controller and the Ru is formed by connecting as a digital copier and a second device as the first device, one power supply is turned OFF Therefore, it is possible to eliminate the manual recovery work such as restarting the other. In addition, it is possible to eliminate the need for manual recovery work such as restarting both of the devices caused by disconnection of the cable connecting the digital copying machine and the controller.
[0024]
【The invention's effect】
As described above, according to the present invention, in a system in which a digital copying machine as the first device and a controller as the second device are connected, even when one of the power supplies is turned off or the connection cable is disconnected. Manual recovery work such as restarting can be made unnecessary.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an image forming system according to an embodiment of the present invention.
[Explanation of symbols]
10 Digital copier 11, 21 Receiver 12, 22 Transmitter 13, 23 UART
20 Controller 30 Cable

Claims (2)

The first device and the second device is configured by connecting a cable, each having a power which is independent, in the data transmission and reception system for transmitting and receiving data,
The first device and the second device are signals indicating that the power supply of their own device has been turned off to a terminal for controlling the output signal level of the receiver on the other side via resistors pulled up to the respective power supplies. Connect the signal line to send
The receiver has a function of setting all output signals to a level indicating a break state of serial communication when a signal indicating that the power of the counterpart device is turned off is applied to the terminal. data transmission and reception system to be. When the signal cable connecting the first device and the second device is disconnected,
The receiver, the data transmission and reception system according to claim 1, characterized in that it has a function of a level of total output signal means a break status of the serial communication.

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