JP2716411B2 - Synchronously controllable printer LAN adapter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an Ethernet LA.
More particularly, the present invention relates to a network print server adapter for connecting a printer to a network and connecting the printer to a network, and more particularly to a synchronous control method for starting up an interface between the adapter and the printer when power is turned on.

[0002]

2. Description of the Related Art A network print server adapter (hereinafter, referred to as a printer LAN adapter or simply an adapter) is an external type in which an Ethernet LAN and a printer are connected to each other and used as an option board in a printer. Types are widely used.

As shown in FIG. 5, a communication control circuit 2 for controlling communication with an Ethernet line is provided inside the adapter.
1, a memory 22 for storing data and control programs, an ASIC 24 for editing and processing data, a printer interface circuit 25 for inputting and outputting data to and from a printer, and a CPU 23 for controlling these components in accordance with a program sequence.

[0004] Here, when the operation of each part is sequentially examined after the power supply of the power supply unit 30 of the adapter is turned on, the power supply circuit 26 is activated by turning on the power switch, and the control unit 20 receives + 5V.
Supply. Next, the CPU starts the operation by the control program stored in the memory. Immediately after power-on, C
The PU operation is almost spent for the initialization of the communication control circuit 21 and the ASIC 24, during which the signal condition of the printer interface circuit 25 is usually not determined. Only after the initialization is completed and the execution of the control program shifts to the step of specifically controlling the communication means of each interface, the signal condition of the printer interface circuit 25 becomes a state in which transmission and reception with the printer are enabled, and the printer recognizes the signal condition. Leads to. During that time, printer operation is not guaranteed.

When the operation of each part when the power supply to the adapter is cut off is sequentially examined, first, the power supply circuit 26 does not operate due to the turning off of the power supply switch, and the voltage of +5 V supplied to the control unit 20 gradually decreases. To go. When the supply voltage has dropped the rating of the logic element used in the circuit, the control unit 20 has stopped functioning. Therefore, the signal condition of the printer interface circuit 25 is not determined again, and the printer itself recognizes a state where transmission and reception are impossible.

On the other hand, even if the state of the adapter and the printer interconnection interface when the printer power switch is turned on and off is viewed, the same conditions as those in the operation of each adapter described above may occur. In other words, in any case, even temporarily until the power supply is determined and the operating conditions are determined,
It is inevitable that the logic state of the interface becomes indefinite and the side that mistakenly recognizes it causes a malfunction.

Conventionally, the power of the adapter is often turned on or off frequently because of its usage. In addition, the operation of the printer is started after the operation of the adapter is started from the position of the network print server, or the operation of the printer is stopped. A common procedure is to stop the adapter operation after that. Therefore, in that case, only the malfunction of the adapter that would be caused by the indetermination of the interface signal when the printer power is turned on or off with the adapter turned on is taken up. Since the printer is originally used by a host connection, measures for preventing problems in the same use environment as in the case of the above-described adapter operation are taken by the printer.

In this method, a circuit is generally constructed so that a DCN signal to be output when all other signals output from the printer among the output signals of the printer are valid is assured. is there. In other words, the low level is maintained from when the printer power is turned on until the printer operation is determined,
This is a method of setting a high level for the first time when permitting an interface operation.

[0009]

The first problem is that, in the prior art, if the power supply of the adapter and the printer is turned on in a non-procedural manner, there is a high possibility that one or both of them will malfunction. This is particularly noticeable when the printer power is turned on and the adapter power is turned on later.

[0010] The reason is that the adapter outputs data to the printer or resets the data. Therefore, it is difficult to suppress signals even transiently.・ Because few printers take in and monitor the logic high signal.

[0011] Printers that capture the host logic high signal are the most recently adopted IEEE p12.
The printer conforms to the 84 standard, and the printer before that executes printing as long as it receives a strobe signal and data.

Therefore, in the case of the latter printer, there are not a few cases where a condition which has occurred transiently when the above problem is involved is erroneously detected, resulting in erroneous printing or paper ejection.

A second problem is that, in the prior art, when a communication failure occurs between each PC client and the adapter on the Ethernet LAN, it is necessary to restart not only the adapter but also the printer. Normal recovery is not possible in many cases.

The reason is that a communication sequence is established between the adapter and the printer by handshaking. If one of the adapters asynchronously forcibly stops the operation, the other causes an error. This is because it may cause it. Whether the lock state occurs or not depends on the conditions under which the operation is stopped and under what conditions, or the granularity of adapter and printer processing support, but in any case, it is extremely difficult to suppress the occurrence under all conditions .

A third problem is that when the adapter is installed on the back side of the printer or in a place away from the printer from an installation environment, forgetting to turn off the power is likely to occur.

The reason is that the adapter has a smaller volume than the printer, so that the adapter tends to be in the shadow of an object.
In addition, in a network environment, the printer and the adapter are often set apart from each other, so that it is difficult for the operator to see it.

An object of the present invention is to solve the first, second, and third problems described above, to significantly improve the operability of a printer LAN adapter, and to perform a communication operation between the adapter and the printer when the power is turned on / off. It is an object of the present invention to provide a printer LAN adapter capable of performing synchronous control for setting up an interface for realizing an adapter capable of ensuring reliability of the printer.

[0018]

SUMMARY OF THE INVENTION A printer LAN according to the present invention
The adapter includes an operation detecting means (4 in FIG. 1) for judging an operable state of the printer from a printer signal when starting up the adapter operation after turning on the printer power, and a control unit of the printer LAN adapter based on the judgment result of the operable state. Power supply means (5 in FIG. 1) for controlling on / off of power supply to the power supply; time measuring means (6 in FIG. 1) for counting a predetermined time from the start of power supply to the control unit; The inside includes signal blocking means (7 in FIG. 1) for blocking a signal sent to the printer.

More specifically, the operation of each means will be described. When the power of the printer is turned on and the system for receiving data is prepared, the printer sends out a fixed state as an output signal. The adapter determines the operable state of the printer according to a predetermined printer output condition. This is the role of the motion detecting means. The determination result of the operation detecting unit is transmitted to the power supply unit, and when it is determined that the printer is operable, power supply to each control unit is started. When the power supply is started, the output signal from the adapter to the printer is cut off for a certain period of time by the measuring means and the signal cutoff means. The output signal is prohibited from being transmitted until the control unit starts operation and can determine the printer interface, that is, until the adapter itself is ready. Only after the interface of the adapter is determined is the output signal cut off, and all signals are sent to the printer simultaneously. Now that the signal states of both the printer and the adapter have been determined, the conditions for normal communication can be set here.

As described above, the start of the adapter operation, the determination of the output signal, and the sequential control are advanced in synchronization with the printer power-on and the subsequent printer operable state, thereby creating an intercommunicable state. In this sequence, a fixed procedure is always performed, and the sequence is not disrupted. The same applies to a case where the power of the printer is once turned off and restarted due to a communication error or the like.

[0021]

Next, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG.
Printer LAN adapter 1 according to an embodiment of the present invention
Is a controller that controls the entire adapter, a printer interface circuit 3 that controls input / output signals 10 to and from the printer, and one or more signals 11 input from the printer through the printer interface circuit 3 to enable the printer to operate. An operation detection circuit 4 for judging a state, a power supply circuit 5 for starting power supply to the adapter by a remote signal 12 transmitted when the operation detection circuit 4 determines that the printer is operable, and detecting the start of power supply. A power-on reset circuit 6 for sending out a reset pulse 13 having a fixed time width, and forcibly outputting one or a plurality of signals 14 output from the printer interface circuit 3 to the printer only for a certain time corresponding to the reset pulse width. And a signal cutoff circuit 7 for inhibiting.

Next, the operation of the embodiment of the present invention will be described.
This will be described in detail with reference to FIGS.

First, as shown in FIG. 2, when the printer power is turned on (step 40), the operation follows the following sequence. After the power is turned on, the printer LAN adapter 1 takes in the signal 10 output by the printer via the printer interface circuit 3 (step 41), and the operation detection circuit 4 constantly monitors the input signal group 11. This signal group only needs to be able to determine the operation state of the printer,
We are not particular about the number. For example, if a DCN signal, which is an output of the printer, is transmitted from the printer and the printer enters an operable state, the operation detection circuit 4
Upon detecting the CN signal, the remote signal 12 is generated (steps 42 and 43). Upon receiving this remote signal, the power supply circuit 5 operates and starts supplying +5 V into the adapter (step 44).

On the other hand, the power-on reset circuit 6 in the adapter detects this +5 V, and turns on the reset pulse 13 having a certain width at the same time as the rise of +5 V (step 45). While the reset pulse is being output, the signal cutoff circuit 7 cuts off the output signal group 14 sent from the printer interface circuit 3 and does not send it to the printer (step 46). Then, when the reset pulse is released, the transmission of the output signal group 14 is permitted (steps 47 and 48). The number of signals to be cut off depends on the circuit conditions of each adapter and printer, and cannot be limited. The above flow is also shown in the operation time chart of FIG.

Next, as shown in FIG. 3, when the printer power is turned off (step 51), the operation follows the following sequence. Now, the operation detecting circuit 4 outputs the output D of the printer.
If the CN signal is being monitored (step 52), the DCN signal is turned off by turning off the printer power, and the remote signal is also turned off (step 53, step 53).
54). Therefore, the operation of the power supply circuit 5 is stopped, and each input / output signal is in an undefined state (step 55). The above flow is also shown in the latter half of the operation time chart of FIG.

Here, it should be added that, since +5 V is not supplied to the adapter until the power supply circuit 5 is activated after the printer becomes operable, a part of the printer interface circuit 3 and the operation detection circuit 4 and the power supply The switching unit of the supply circuit 5 includes a printer input / output signal group 10.
Needless to say, it must be operable by a supplied current source.

As described above, the start of the adapter operation, the determination of the output signal, and the sequential control are advanced in synchronization with the printer power-on and the subsequent printer operable state, thereby creating an intercommunicable state. In this sequence, a certain procedure is always performed, and there is no disruption.

[0028]

The first effect is that the present invention controls the power supply of the adapter only by operating the power supply of the printer, so that the procedure for turning on the power supply is realized as a result. The reason for this is that the remote control of the adapter power supply and the occurrence of transient signal failures that occur when the power is turned on can be suppressed.

The second effect is that even if the adapter is installed on the back side of the printer or in a place away from the printer from the installation environment, it is expected that the number of forgetting to turn off the power is reduced. The reason for this is that the remote control is performed such that only the operation of the printer power supply is performed and the adapter power supply is interlocked with the operation.

The network print server adapter produced by the above technical effects can remarkably improve the ease of use required by the user and the prevention of a decrease in reliability due to operation.

[Brief description of the drawings]

FIG. 1 is a block diagram of a printer LAN adapter according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of the printer LAN adapter of FIG. 1;

FIG. 3 is a flowchart illustrating an operation of the printer LAN adapter of FIG. 1;

FIG. 4 is a time chart illustrating an operation of the printer LAN adapter of FIG. 1;

FIG. 5 is a block diagram showing a configuration of a conventional printer LAN adapter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer LAN adapter 2 Control part 3 Printer interface circuit 4 Operation detection circuit 5 Power supply circuit 6 Power-on reset circuit 7 Signal cutoff circuit 10 I / O signal group 11 Input signal group 12 Remote signal 13 Reset pulse

Claims (3)

(57) [Claims] 1. A local area network (LAN)
Operation detecting means for judging a printer operable state from a printer signal when starting up the adapter operation after turning on the printer power, in a printer LAN adapter for connecting the printer and the printer and transmitting / receiving data to / from the printer; Power supply control means for controlling on / off of the power supply inside the printer LAN adapter from the determination result of the possible state, time measuring means for counting a certain time from the start of the power supply, and a sending signal to the printer during the certain time And a signal blocking unit for blocking a signal. 2. A printer LAN adapter for connecting a LAN to a printer, comprising: a printer interface circuit connected to the printer; and one or more signals input from the printer through the interface circuit to enable the printer to operate. A power supply circuit for starting power supply to the adapter when the operation detection circuit determines that the printer is operable, and transmitting a pulse having a predetermined time width upon detecting the start of power supply. A printer LAN adapter, comprising: a power-on reset circuit; and a signal cutoff circuit for forcibly prohibiting output of one or a plurality of signals output from the interface circuit to the printer only for a predetermined time corresponding to the pulse width. 3. The power supply control part of the operation detection means and the power supply control means is supplied with power from the printer until the power supply is started. Printer LAN adapter.