JPH01219925A - Printer buffer device - Google Patents

Abstract

PURPOSE:To improve the processing efficiency of each personal computer by providing individual data input means, whose number corresponds to the number of personal computers, and prescribed storage areas. CONSTITUTION:A printer buffer device 10 allows two personal computers 30 and 32 to share one printer 50. Data output terminals of personal computers 30 and 32 are connected to input terminals of input circuits 12 and 14 through data busses 34 and 36, and control terminals are connected to control terminals of a control circuit 26 through control lines 38 and 40. Input circuits 12 and 14 take in data character by character and give it to RAMs 16 and 20, and write/read control signals or the like for this data are given from the control circuit 26. The control circuit 26 transmits and receives control signals and controls each part in the buffer device 10. When one personal computer requests the printing output while data from the other personal computer is outputted by the printer 50, this request is accepted by RAMs 16 and 20 to hold data in a prescribed area and the output processing is performed thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printer buffer device for allowing a plurality of computers to share one printer.

[Prior Art] FIG. 2 shows a conventional example of this type of printer buffer device. This printer buffer device 100 allows two personal computers (personal computers) 108 and 110 to share one printer 112 by switching a switch or a multiplexer 102.

When the printer 112 is not in use, the computer 108
sends a predetermined request signal to control line 1 to perform printout.
18, the control circuit 1 of the buffer device 100
06 accepts the request and switches the switch 102 to the personal computer 108 side. As a result, data output from the personal computer 108 onto the data bus 114 is written to the RAM 104 via the switch 102. This allows the personal computer 108 to finish outputting data for printout in a short time and move on to other processing. In the buffer device 100, the control circuit 106 is a RAM
Data is read out character by character from 104 and provided to printer 112 using a predetermined transmission procedure.

[Problems to be Solved by the Invention] A problem occurs when a printout request is received from another personal computer 110 while data from the personal computer 108 is being printed out by the printer 112 as described above.

In this case, the personal computer 110 sends a predetermined request signal to the control line 1.
However, since the RAM 104 is in use, the control circuit 106 returns a signal indicating that the request will not be accepted. Therefore, the personal computer 110 should not wait while requesting print output.Normally, once the personal computer requests print output, it will be unable to perform other processing.
The pan controller 110 remains in a standby state, which is unfavorable in terms of processing efficiency. However, if you switch to another process and then request print output again after a while, the control becomes complicated and the system becomes expensive.

In the above example, there were two personal computers, but the same problem occurs when there are three or more personal computers, or two or more word processors or other computer equipment.

The present invention has been made in view of such problems, and an object of the present invention is to provide a printer buffer device that eliminates the need for any of a plurality of computers to stand by for print output.

[Means for Solving the Problems] To achieve the above object, the present invention provides a printer buffer device that is connected between a plurality of computers and one printer and selectively supplies data from the computers to the printer. a data input means for individually inputting data from the computers; and a storage means for storing the data for each computer inputted to the data input means in a predetermined storage area allocated in advance to each computer. and; data reading and sending means for selectively reading data for each computer from the storage means and sending it to the printer.

[Function] In the present invention, by providing a number of individual data input means and storage areas corresponding to the number of computers, data from one computer can be printed out by a printer while data from another computer is being printed out. When there is a request for print output from the computer, the storage means accepts the request and holds the data from the computer in a predetermined storage area. When the print output process for the previous computer is completed, the data reading and sending means switches to the print output process for the next printer.

This eliminates the need for any computer to stand by for print output, increasing processing efficiency.

[Embodiment] FIG. 1 shows the configuration of a printer buffer device according to an embodiment of the present invention. This printer buffer device 10 includes two
One personal computer 30.324Z (7) and one printer 50 are shared.

The data output terminals of the personal computer 30.32 are respectively connected to the input terminals of the input circuit 12.14 via a data bus 34.36. Further, the control terminals of these personal computers are respectively connected to corresponding control terminals of the control circuit 26 via control lines 38 and 40.

Input circuits 12 and 14 take in data one character at a time and apply it to RAMs 16 and 20, respectively. These R.A.
The storage capacity of the M16.20 has been selected to be large enough to store the maximum amount of data normally output at one time by the PC 30.32. Addresses for writing and reading RAM 16.20 are respectively provided by address circuits 18.22 containing address counter circuits. In addition, chip enable signals and write/read control signals for the RAMs 18 and 20 are provided from the control circuit 26 (
However, the control lines for this are not shown). RAM16.
The data output from 20 is output character by character onto data bus 52 via output circuit 24 including a selector circuit.

The control circuit 26 connects to the personal computer 3 via control lines 38 and 40.
0.32 and the printer 50 via the control line 54, and controls each section within the buffer device 10. especially,
The address circuit 18.22 is instructed to start and end the generation of address signals, and the output circuit 24 is instructed to
6. Instruct switching to either side of 20. The control circuit 26 also receives data output from the output circuit 24 in order to detect data indicating the end of printing.

Thus, in this embodiment, input circuits 12 and 14 constitute input means, RAM 16.20, address circuit 18.22 and control circuit 26 constitute storage means, and address circuit 18.22 and control circuit 26 constitute storage means. and the output circuit 24 constitute data reading and sending means.

Next, the operation of the printer buffer device 10 having such a configuration will be explained. Now, when the printer 50 is not in use,
Assume that the personal computer 3o outputs a predetermined request signal onto the control line 38 in order to perform printout. Then, the control circuit 26 outputs a signal permitting this onto the control line 38 and instructs the address circuit 18 to generate an address signal. As a result, data from the personal computer 30 is input character by character into the input circuit 12, and then R
It is written to a predetermined location of AM18. At this time, the address circuit 18 generates an address signal in synchronization with the input of the input circuit 12. In this way, data for one printout from the personal computer 30 is stored in the RAM 18.

When the output of all data from the personal computer 30 is completed, the personal computer 30 outputs a predetermined control signal and proceeds to execute other processing. In response to the control signal, the control circuit 26 outputs the output circuit 24.
is switched to the RAM16 side, and the RAM18
The address circuit 18 generates an address specifying the first address of the address.

As a result, the first data for one character read from the RAM 16 passes through the output circuit 24 and is transferred to the data bus 5.
2 is output. At the same time, the control circuit 2
6 outputs a strobe signal onto the control line 54 to notify the printer 50 that data has been sent. In response to this, the printer 50 takes in the data. When the printer 50 is ready to receive the next data, the printer 50 stops the busy signal and issues an acknowledge signal. Then, the control circuit 26 reads data at the next address from the RAM 18, and transfers this data to the printer 5 in the same manner as the first data.
Give to 0. In this manner, buffer circuit 10 provides data character by character to printer 50 in the same manner as if personal computer 30 provides data to printer 50.

Assume that while the printer 50 is printing out data from the personal computer 30, the personal computer 32 requests the printout. The control circuit 26 allows the
2 is stored in the RAM 20 via the input circuit 14. With this, the personal computer 32 finishes outputting data for printout in a short time and starts other processing.

On the other hand, the control circuit 26 monitors the data output from the output circuit 24, and when the last data is detected, the control circuit 26 outputs the data from the output circuit 24.
is switched to the RAM20 side, and the RAM20
The address circuit 22 generates an address specifying the first address of the address, and the output circuit 24 outputs the first data for one character read from the RAM 20 onto the data bus 52. As a result, the data is taken into the printer 50 and printed out.

As mentioned above, this printer buffer Hf1lO has 2
By providing two independent input circuits 12, 14 and RAM 16° 20 corresponding to two computers 30, 32, it is possible to request print output from one computer while printing data from the other computer. is issued, accept it, retain the data from that computer in a designated storage area, and wait until the print output processing on the previous computer side is completed before printing it on the subsequent computer side. Let the process execute. therefore,
Each personal computer does not have to wait for print output, so its processing efficiency does not decrease.

Note that for three or more personal computers, an input circuit and a storage device may be added. Furthermore, the same applies not only to personal computers but also to word processors and other computer equipment.

Further, although the above-described embodiment uses a RAM as a storage device, it is also possible to use a disk device.

[Effects of the Invention] The present invention, having the above-described configuration, provides the following effects.

By providing a number of individual data input means and a predetermined storage area corresponding to the number of computers, while data from one computer is being printed out by a printer, data from another computer can be printed out. When a request is made, it accepts the request, holds the data from the computer in a designated storage area, and issues the request once the print output process that was being executed at the time of the request has finished. Since the print output processing is switched to the computer, there is no need for any computer to wait for print output, and the processing efficiency of each computer can be increased.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a printer buffer device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional printer buffer device. In the drawings, 10... Printer buffer device, 12.14... Input circuit, 16.20... RAM. 18.22...address circuit, 24...output circuit, 26...control circuit, 50...printer.

Claims (1)

[Scope of Claim] A printer buffer device connected between a plurality of computers and one printer, and selectively providing data from these computers to the printer, comprising: a data input means for inputting the data separately for each computer; a storage means for storing the data for each computer input to the data input means in a predetermined storage area allocated in advance to each computer; A printer buffer device comprising: data reading and sending means for reading out another data and sending it to the printer.