JPH02130180A - Printer - Google Patents

Abstract

PURPOSE:To effectively and selectively use a printer and to alleviate the user's work and the like of a host computer by monitoring the presence or absence of the communication of the computer by using clocking means. CONSTITUTION:A CPU 21 monitors whether any host computer is communicated with a printer or not, controls a counting clock.reset signal generator 26 if communicating, and supplies a reset signal 31 to a counter 14. Thus, the counted value of the counter 14 is always reset while the printer receives printing data from the computer. On the other hand, if the communication of the computer is finished or the supply of the printing data is temporarily interrupted, the CPU 21 controls the generator 26 to sent one counting clock 32 to the counter 14. When a time is elapsed in this state and the counter 14 counts a predetermined value, a control signal is sent to a communication unit switching circuit 25 to be switched to a communication unit 11 or 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printer device connected to a plurality of host computers.

[Conventional technology]

For example, a relatively expensive printer device such as a laser printer that can perform printing processing at a relatively high speed is often connected to a plurality of host computers for economic reasons. However, many of these printer devices operate simultaneously with these multiple host computers! , : Does not have the function of communication. Therefore, in reality, a device called a printer switcher is placed between the printer device and these higher-level host computers, and by pressing the selection switch on the panel of this device, The printer device was connected to a desired upper host combination coater.

[Problem to be solved by the invention]

However, when using such a printer switching device, the following problem occurred.

(b) When a higher-level host computer wants a printer to print out, the user must switch the printer switch, but in this case, if another higher-level host computer is in use. It is necessary to confirm whether or not this is the case, and if this is neglected, a problem arises in that the printing operation currently in progress is unilaterally interrupted.

(b) The person making the switch had to go all the way to the printer switch, which was complicated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a printer device that allows the device side to select an upper host computer with which to communicate.

[Means to solve the problem]

The present invention provides (i) a plurality of print data communication means each connected to a host computer and receiving print data; (1) selection means for selecting one of these print data communication means; and (iii) a selection means for selecting one of these print data communication means. (1v) a reset means for resetting the timekeeping operation of the timekeeping means when the upper host computer selected by the selection means is communicating; and (V) a timekeeping means for counting a predetermined time. The printer device is provided with selection control means for causing the selection means to select another print data communication means when the time is counted.

That is, in the present invention, when the selected higher-level host computer is not communicating, the timing means determines this, and the selection control means connects it to the next higher-level host computer, so that it is sequentially connected to the next higher-level host computer. Switch the upper host computer. Note that the time measured by the clock means may include a difference between the time for detecting a communication interruption time in a higher-level host computer during communication and the time during standby when no higher-level host computer is communicating. good. That is, by shortening the time required to complete time measurement during standby, there is an advantage that the response to the appearance of a higher-level host computer that starts communication becomes faster.

〔Example〕

The present invention will be described in detail with reference to Examples below.

FIG. 1 shows the main parts of a printer device according to an embodiment of the present invention. To simplify the explanation, it is assumed that the printer device of this embodiment is connected to two upper host computers.

Of course, the printer device of the present invention can be configured to be connected to three or more host combinations.

Now, this printer device includes a first communication section 11 for communicating with a first host computer, and a second communication section 12 for communicating with a second host computer. . These communication units 11 and 12 are connected to a control unit 1 configured by a microcomputer, for example.
Connected to 3. The control section 13 is connected to a counting circuit 14 . The counting circuit 14 can be provided with a dedicated counter for counting clocks, but it can also be realized by writing the counted value into a RAM (random access memory) area that constitutes the control section 13.

FIG. 2 shows the main parts of the control section.

The control unit 13 includes a CPU (central processing unit) 21, and connects the ROM 23 and R via a bus 22 such as a data bus.
It is connected to the AM 24, the communication section switching circuit 25, and the counting clock/reset signal generation circuit 26. Here RO
M23 is a read-only memory that stores a program for controlling this printer device, and RAM2
71 is a working memory for temporarily storing various data. Further, the communication section switching circuit 25 is a circuit that switches between the first communication section 11 and the second communication B12 shown in FIG.
is a circuit that outputs a counting clock or cent signal to the counting circuit shown in FIG. Note that the control unit 1
3 is a circuit section or I that controls a recording section, etc. (not shown)
Although there are 10 ports, they are omitted because they are not directly related to the description of the present invention.

FIG. 3 is a diagram for explaining control when the printer device configured as described above switches the communication section.

The CPU 21 monitors whether or not this printer device is communicating with any of the upper host computers (step ■), and if it is communicating (Y), controls the counting clock/reset signal generation circuit 26. Counting circuit 14
A reset signal 31 is supplied to (step ■). As a result, the count value of the counting circuit 14 is always reset while the printer device is receiving print data from the host combination coater.

On the other hand, when the communication with the host computer ends or the supply of print data is temporarily interrupted (step ■; N), the CPU 21 controls the counting clock/reset signal generation circuit 26 to send the counting clock to the counting circuit 14. 3
Send one 2 (step ■). Then, the count value information 33 of the counting circuit 14 is inputted manually, and it is determined whether the count value information 33 has reached a predetermined value (step 2). If this value has not been reached (N), the host computer currently communicating interprets that the transmission of print data has been temporarily interrupted, and resumes the control shown in this Figure 3 from step ■. (return). That is, in this case, until the counting circuit 14 reaches a predetermined value, the connected state with the currently connected upper host combination will be maintained.

When time elapses in this state and the counting circuit 14 counts a predetermined value (step 2; Y), the CPU 21 controls to generate the reset signal 31 to reset the counted value (step 2). Then, a control signal is sent to the communication section switching circuit 25 to switch the first communication section 11 to the second communication section 12 if it is connected. Second communication unit 12
If it is connected, it will be switched to the first communication section 11 (step 2). Thereafter, control is resumed from step (3), and if the newly selected higher-level host computer is communicating, it will respond to this and start sending print data.

Note that, for example, if communication is terminated in the first communication unit 11 and switched to the second communication unit 12, and it is found that communication is not being performed in this second communication unit 12, either of the upper hosts It is possible to quickly respond to the start of communication by alternately and quickly switching between the two communication units IL12 until the combiator starts communication. Therefore, it is also effective to set the predetermined value in step (2) to be different when no upper host combicoater is communicating and when monitoring interruption of communication.

Furthermore, in the embodiment, a description of the case where two or a plurality of higher-level host computers start communication one after another is omitted; The problem can be solved by sending out the problem. That is, the upper host computer to which the connection was not made detects that this control signal has not been sent within a predetermined period of time, and after a certain period of time, attempts communication again. If none of the other higher-level host computers are communicating at this retransmission stage, the printer device selects the higher-level host computer for this retransmission and the connection is fixed, and it is ready to receive print data. It will become.

〔Effect of the invention〕

As explained above, according to the printer device of the present invention, since the timekeeping means is used to monitor the presence or absence of communication with the host computer, there is a possibility that communication of print data may be interrupted for a short period of time for some reason. The connection status with the higher-level host computer is maintained even when the host computer is connected to the host computer. As a result, printer devices can be reliably selected and used among a plurality of host computers, and the work of the user of the host computer is reduced, which improves office efficiency.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention, of which FIG. 1 is a block diagram showing the main parts of the printer device, and FIG. 2 is a block diagram showing the main parts of the control section shown in FIG. 1. figure,
FIG. 3 is a flowchart showing control when the printer device switches communication units. DESCRIPTION OF SYMBOLS 11...First communication unit, 2...Second communication unit, 13...Control unit, 4...Counting circuit, 21... ...cpu. 3...ROM, 24...RAM. 5...Communication section switching circuit, 6...Counting clock/reset signal generation circuit,
1...Reset signal, 2...Counting clock. Applicant: NEC Co., Ltd. Agent: Patent attorney: Umeo Yamauchi (twice)

Claims (1)

[Scope of Claims] A plurality of print data communication means each connected to a host computer and receiving print data, a selection means for selecting one of these print data communication means, and a clock means for timing a predetermined time. and reset means for resetting the timekeeping operation of the timekeeping means when the upper host computer selected by the selection means is communicating; and when the timekeeping means has timed a predetermined time, the selection means receives other print data. A printer device comprising: selection control means for selecting a communication means.