JPH0816893B2 - Communications system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a communication system including an image reading device, an image recording device, a processing device, and a connection switching device.

[Prior Art] In a conventional system such as an image processing system, at least one image input device such as an image reader and at least one image output device such as an image printer are connected to each central processing unit (hereinafter referred to as CPU). There are many cases.
However, in this type of system, the usage rate of these image input / output devices in the total processing time is extremely small, and despite such usage conditions, each CP
It is very wasteful to connect expensive image input / output devices to each U. For this reason, there has been proposed a system in which a printer control device generally called a print server is provided and a printer is shared by a plurality of CPUs by a local area network (hereinafter referred to as LAN). However, in such a system, LAN control and shared control become large,
Not suitable for small scale shared control.

It is also possible to perform a copying operation as a copying machine using an image reader and an image printer. At that time, if the operator is allowed to perform a mode switching operation, it is convenient for the operator who was performing the copying work. Will be bad.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-described conventional example, and prevents improper switching operation without adopting a complicated configuration and performs copying work. Copying work can be easily performed without causing the operator who wants to perform a troublesome switching operation, and it is easy to determine whether or not the processing device that requested the use of the image reading device can currently use the image reading device. It is an object of the present invention to provide a communication system capable of making a decision.

[Means for Solving Problems] In order to achieve the above object, the communication system of the present invention has the following configuration. That is, in a communication system including an image reading device, an image recording device, a processing device, and a connection switching device, the image reading device has a master mode for controlling the image recording device and a slave mode controlled by the processing device. However, the connection switching device executes the copying operation by the image reading device and the image recording device by pressing the start key so that the image reading device operates in the master mode until the connection request from the processing device is detected. When the connection request from the processing device is detected by monitoring whether the image reading device and the image recording device are communicating with each other, the image reading device and the image recording device If communication is in progress, an unacceptable message is returned to the processing device,
If the image reading device and the image recording device are not in communication, the image reading device connects the processing device and the image reading device so that the image reading device operates in the slave mode, and further, a disconnection request from the processing device. Is detected, the copying operation by the image reading device and the image recording device is made ready by pressing the start key so that the image reading device operates in the master mode.

[Operation] In the above configuration, the image reading apparatus operates in the master mode until the connection request from the processing apparatus is detected, so that the copying operation by the image reading apparatus and the image recording apparatus can be executed by pressing the start key. Leave it
When the connection request from the processing device is detected, if the image reading device and the image recording device are communicating, an unacceptable message is returned to the processing device, while the image reading device and the image recording device When not in communication, the image reading device connects the processing device and the image reading device so that the image reading device operates in the slave mode. Further, when a disconnection request from the processing device is detected, the image reading device operates so that the copying operation by the image reading device and the image recording device can be executed by pressing the start key so as to operate in the master mode. .

[Embodiment] An embodiment of the present invention will be described in detail below with reference to the drawings.

[Connection Diagram (FIG. 2)] FIG. 2 is a connection diagram showing an embodiment according to the present invention.
Image readers 1 and 2 are shared by the CPU via the shared control device 3.
And the image printer 5 are shared. The image reader 4 inputs the reflected light of the original image to the photoelectric conversion element by the optical means, converts the input light into an electric signal sequence by the photoelectric conversion element, and outputs it as image data.

The image printer 5 inputs the image data as an electric signal sequence and reproduces the image on a sheet as a dot image.
This image print has a so-called laser beam printer or a so-called laser beam printer that scans a laser beam to form a latent image corresponding to data on a photosensitive drum, and prints on a sheet by development and transfer. It is possible to use an electrostatic printer, an ink jet printer that ejects and prints ink particles, or a thermal printer (including a thermal transfer printer) that prints by heat-sensitive color development. The image reader 4 can also directly connect to the image printer 5 to function as a copying machine.

The shared control device 3 connects a predetermined CPU to the image reader 4 or the image printer 5 in response to a connection request from the CPU 1 or the CPU 2. When neither the CPU 1 nor the image reader 4 is using the image reader 4 or the image printer 5, the image reader 4 and the image printer 5 can be automatically connected and used as a transfer machine. ing.

[Configuration diagram of shared control device (FIG. 1)] FIG. 1 is a block diagram showing a configuration of a shared control device 3 according to an embodiment of the present invention.

A connection switching circuit 11 switches the connection between the image reader 4 and the image printer 5 and the CPUs 1 and 2 by a switching signal 16 from the control unit 10. It should be noted that part of the interface signals of the image reader 4 and the image printer 5 is converted into a status signal by the signal lines 14 and 15, respectively, as a status signal.
0 is input, and the control unit 10 determines the image reader 4 and the image printer 5 based on these status signals.
Monitor the operating status of. A control unit 10 controls the shared control device 3 based on each status signal and interface signals 17 and 18, and a microprocessor (MPU) 1
00, a ROM 101 containing the control program and data thereof, and a RAM 102 as a work area.

Reference numerals 17 and 18 are control signals input from the CPU 1 and the CPU 2 to the control unit 10 for shared control, and here, data transmission / reception by serial data is performed. 19,21 is C
Image reader interface signal of PU1 and CPU2, 20,
Reference numerals 22 are image printer interface signals of CPU1 and CPU2, respectively. Switches 12 and 13 in the connection switching circuit 11 are operated in cooperation with each other by a switching signal 16 from the control unit 10 to switch the contacts to any of A to C,
It controls the connection between U, image reader 4, and image printer 5.

The image reader interface signal 23 and the image printer interface signal 24 are roughly divided into a communication system signal for communicating commands and statuses and an image system signal for inputting / outputting image data. The signal 23 and the image printer interface signal 24 are the image system signals whose input and output directions are opposite to each other.

When functioning as a copying machine, the image reader 4 is a master mode in which the image printer 5 is directly controlled, and this mode is called an offline mode. At this time, the switches 12 and 13 are switched to the contact C side by the switching signal 16 from the control unit 10.

On the other hand, when the image reader 4 is connected to one of the CPUs 1 and 2, the image reader 4 operates in the slave mode, and the read operation is performed under the control of the CPUs 1 and 2. This mode is called the online mode. Now, for example, when the copy start key of the image reader 4 is pressed in the offline mode, the image reader 4 starts reading an image, sends image data to the image printer 5 to execute printing, and performs a copy operation as a copying machine. Run.

Note that such switching between the online mode and the offline mode is performed by issuing an online command or an offline command from the control unit 10 to the image reader 4 via the signal line 14 by a communication system signal of the image reader interface signal. Done.

The interface signals 17 and 18 are serial interface signals commonly known as RS232C,
Through this serial interface signal, the control unit 10
Communicates commands and status for shared control with CPU1 and CPU2. If the CPU1 wants to use the image printer 5 now, the CPU1 checks the status of the shared control device 3 through the interface signal 17, issues an open command if the image printer 5 is available, and declares that the CPU1 will use it exclusively. To do. When the open command is accepted and the exclusive state is reached, predetermined printing is performed, and after the printing is completed, a close command is issued to declare the release of the exclusive state, and the series of sequences is ended.

When the control unit 10 switches the connection state with the connection switching circuit 11, it may not be switched depending on the operation states of the image reader 4 and the image printer 5. First of all, this is an image reader 4 and an image printer 5.
Is the time when the CPU1 or CPU2 is in the exclusive state, which means from the reception of the open command to the reception of the close command from the CPU. Secondly, even in the offline mode, that is, in the state in which no CPU is monopolized, it must be prohibited during so-called local copying such as operating as a copying machine. Therefore, the control unit 10 needs to monitor the communication system signal of the image reader interface signal to intercept the communication between the image reader 4 and the image printer 5 and detect whether or not it is during the copying period.

The sequence of the copy operation is as follows. First, the photosensitive drum of the image printer 5 is rotated, and when the rotation reaches a certain number of rotations, the paper is fed from the paper cassette to a predetermined start position. The above is the copy preparation stage. Next, copying is performed by synchronizing the read operation of the image reader 4 and the print operation of the image printer 5. After discharging the paper, stop the rotation of the photosensitive drum,
A check is made to see if there is an abnormality such as a jam, and a series of copy operations is completed. Therefore, the control unit 10 uses the image reader 4
And the image printer 5 are intercepted, the period from the photosensitive drum rotation start command to the end status after the photosensitive drum rotation stop command is detected to detect the copy period, and the switching prohibition period is set. .

The communication system signals of the image reader interface signal and the image printer interface signal both always return the status in response to the command.
It is needless to say that signals must not be switched between the issuance of these commands and the return of the status.

[Description of Operation of Shared Control Device (FIG. 3)] FIG. 3 is a flow chart of a reception operation from the CPU of the MPU 100, which is stored in the ROM 101 of the control unit 10 of the shared control device 3.

First, when an open command is received from the CPU 1 or 2 in step S1, the process proceeds to step S2 to check the usage status of another CPU. If there is an open command from CPU1, if CPU2 is not in use, proceed to step S3 to check if copying is in progress. While copying, or step S2
When CPU2 is in use, the process proceeds to step S4, and an unacceptable message is sent to CPU1.

When none of the CPUs are in use, that is, in the so-called offline mode and when copying is not in progress, that is, when the image reader 4 and the image printer 5 are available, an online command is issued to the image reader 4 in step S5, and the offline mode is set. Switch to online mode more.

At step S6, the switching signal 16 is output and connected to the contacts A of the switches 12 and 13 so as to connect the CPU 1 to the image reader 4 and the image printer 5. This puts CPL1 in a dedicated use state. In step S7, it is checked whether or not the close command is received from the CPU 1, and if it is received, the process proceeds to step S8, and the switching signal 16 switches the contacts of the switches 12 and 13 from A to C. At step S9, an offline command is issued to the image reader 4 to switch from the online mode to the offline mode, and the online standby state is set.

[Description of State Transition Diagram (FIG. 4)] FIG. 4 is a state transition diagram showing state transitions of the image reader 4, the image printer 5, and the sharing control device 3.

After the power is turned on, a predetermined initialization process is performed in 40, and then in the state 41, the offline mode is entered and the offline standby state is entered. Exclusive request from CPU1 and CPU2 (open command)
Is issued, the state shifts to state 42 by issuing an online command to the image reader 4, and the mode is switched to the online mode. Depending on whether it is open from CPU1 or open from CPU2, it becomes the exclusive state of CPU1 or CPU2,
Go to state 43 or 44.

From the exclusive state of CPU1 or CPU2, close CPU1 or CP
When the U2 close command is entered, the online standby state is entered, an offline command is automatically issued to the image reader 4, the state 42 is changed to the state 41, and the standby state is entered again.

When the copy start key is pressed during the offline standby, the state shifts to the state 45 to perform the local copy, and upon completion, the state returns to the state 41 again to enter the offline standby state.

Although the number of CPUs is two in this embodiment, the number of CPUs is not limited to this, and the number of CPUs can be used without limitation.

Although RS232C is used as the serial interface signal for sharing control, another serial interface signal may be used, or a parallel interface signal may be used.

Furthermore, although the connection switching circuit 11 simultaneously switches the image reader interface signal and the image printer interface signal to the same CPU, they may be switched to different CPUs at different timings.

As described above, various modifications can be made without departing from the scope of the present invention.

Although the input / output device has been described as an image input / output device in this embodiment, it is not limited to this and other input / output devices may be used.

As described above, according to this embodiment, there is an effect that a plurality of central processing units can share an image input / output device without changing the interface signal of the original image input / output device.

Furthermore, when the image input / output device is not connected to the central processing unit, the image input / output device can be connected to each other to operate as a copying machine, so that the input / output device can be effectively used.

[Effects of the Invention] As described above, according to the present invention, it is possible to reliably set the mode of the image reading apparatus having the master mode and the slave mode, and prevent the inappropriate operation in the wrong mode. At the same time, the copying operation can be executed without causing the operator who wants to perform the copying work to perform a troublesome selection operation. Further, there is an effect that the processing device that requests the use of the image reading device can easily determine whether or not the image reading device is currently available.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a shared control device according to an embodiment of the present invention, FIG. 2 is a diagram showing connections of the shared control device according to the present embodiment, FIG. 3 is a reception operation flow chart of a control unit, and FIG. FIG. 4 is a state transition diagram of the shared control device. In the figure, 1, 2 ... CPU, 3 ... Shared control device, 4 ... Image reader, 5 ... Image printer, 10 ... Control unit, 11
...... Connection switching circuit, 12, 13 ...... switch, 14, 15 ...... signal line, 16 ...... switching signal, 17, 18 ...... interface signal.

Claims (1)

[Claims] 1. A communication system comprising an image reading device, an image recording device, a processing device and a connection switching device, wherein the image reading device is a master mode for controlling the image recording device and a slave mode controlled by the processing device. The connection switching device controls the copying operation by the image reading device and the image recording device so that the image reading device operates in the master mode until the connection request from the processing device is detected. When the image reading device and the image recording device are in communication with each other by being pressed, the image reading device and the image recording device are monitored when a connection request from the processing device is detected. If the device is in communication, an unacceptable message is returned to the processing device, and the image reading device and the image recording device If the image reading device is not communicating, the image reading device connects the processing device and the image reading device so that the image reading device operates in the slave mode, and when the disconnection request from the processing device is detected, the image reading device masters the image reading device. A communication system characterized in that a copying operation by the image reading device and the image recording device to be operated in a mode is made executable by pressing a start key.