JPH071474B2 - Printer - Google Patents

Description

The present invention relates to a printer equipped with both a parallel interface such as a Centronics interface and a serial interface such as an RS232C interface.

[Prior Art] For example, some printers that are connected to a host computer and receive print data from the host computer to print data include both a parallel interface and a serial interface. This enhances the versatility of the printer by making it possible to select whether to use the parallel interface or the serial interface depending on which device is used as the host computer.

By the way, the parallel interface is a device (printer)
Is provided with an output terminal that sends a BUSY signal when it becomes unable to receive data, and when the cause is the paper end, head-up, ribbon end, etc. of the device, the PAUSE signal is sent, and it is caused by an error in the device. Sometimes an output terminal is provided to send FAULT signal. However, the serial interface only has an output terminal that sends a BUSY signal when the device cannot receive data.

[Problems to be Solved by the Invention] Therefore, when such a printer is connected to the host computer via the serial interface, when the host computer cannot transmit data to the printer, only the BUSY signal comes from the printer. It is impossible to distinguish whether the cause was caused by the data buffer full on the printer side, paper end, head up, ribbon end, or error occurrence. It was impossible to distinguish whether the state was released or the BUSY state was not released without some release operation on the device side.

For this reason, for example, when the BUSY state is entered at the paper end, the operator waits for the time required to release the BUSY state when the host computer side is full of data buffers.
After that, it was determined that the cause of BUSY was on the device side, and I had to work for it.

The present invention has been made in view of such a point. Even when the host computer is connected to the host computer using the serial interface, the cause of the BUSY state is released after waiting for a certain period of time. It is intended to provide a printer that can immediately determine whether or not the release operation should be performed.

[Means for Solving Problems] According to the present invention, when a device cannot receive data to a host computer, a BUSY signal is transmitted and the status occurs at the paper end, head up, ribbon end, etc. of the device. When the device becomes unable to receive data, the parallel interface has an output terminal that sends the PAUSE signal when it occurs, and the FAULT signal when it occurs due to an error in the device. Only the output terminal that sends the BUSY signal when the device cannot receive data. In a printer that has a serial interface that has a serial interface and that connects one of the interfaces to a host computer and receives print data from the host computer and prints data, the serial interface PAUSE signal and FAUL signal An output terminal for transmitting a logical sum signal of the T signal is provided.

[Operation] In the present invention having such a configuration, when the host computer is connected using the serial interface, when the host computer receives only the BUSY signal from the printer, it is released after a lapse of time such as data buffer full. It is judged that it is in the BUSY state and waits. Further, when the logical sum signal of the PAUSE signal and the FAULT signal is received from the printer together with the BUSY signal, it is judged that the printer end needs to perform the release operation because a paper end, a ribbon end or an error occurs in the printer.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a printer and 2 is a host computer connected to the printer 1.

The printer 1 includes a CPU 11 that constitutes a control unit main body,
11 is a ROM 12 in which program data for controlling each part and a character code for printing are stored, a RAM 13 in which various memories for data processing such as a memory for storing printer data are provided, a printer controller 14,
Stepping motor 15 and print head 16 controlled by this printer controller 14, Centronics interface 17 as parallel interface, RS232C interface as serial interface
18 are provided.

The stepping motor 15 drives, for example, a carrier having a print head 16, and the print head 16 is of a dot printing type.

The printer 1 is, for example, RS23 for the host computer 2.
It is connected via the 2C interface 18. In addition,
Depending on the type of host computer, it may be connected via the Centronics interface 17.

The RS232C interface 18 is, as shown in FIG.
I / O port 18 ₁ , multiple gate circuits 18 ₂ , 18 ₃ , 18 ₄ , 18 ₅ ,
A plurality of inverters 18 _6, 18 _7, 18 _8, made such as the output terminal 18 _9, the host computer 2 and the I / O port 18 gate circuit signals transmitted and received between ₁ 18 _{2-18 5,} inverter 18 _6-18 It is supposed to be done through ₈ . Especially I / O port 18 ₁ DT
The BUSY signal is output from the R terminal to the output terminal 18 ₉ via the gate circuit 18 _5, and the RSFLT signal as a logical sum signal input from the Centronics interface 17 described later is output to the output terminal 18 ₉ via the gate circuit 18 _2. Is output to.

As shown in FIG. 3, the Centronics interface 17 includes an I / O port 17 ₁ and a D-type flip-flop 17 ₂ , 1.
7 ₃ , monostable circuit 17 ₄ , multiple inverters, output terminal 17 ₅ ,
It made like the OR gate circuit 17 _6, each inverter transmission and reception of signals between the host computer 2 and the I / O port 17 _1,
Flip-flops 17 ₂ and 17 ₃ , a monostable circuit 17 ₄ and an output terminal 17 ₅ are used. Especially BUSY signal to the output terminal 17 ₅ through the inverters, PAUSE signal, FAULT
RSFLT obtained by ORing the OR gate circuit 17 ₆ with each signal output and the logical sum of the PAUSE and FAULT signals
The signal is output to the RS232C interface 18.

In the RS232C interface 18 and the Centronics interface 17, when the BUSY signal becomes data buffer full on the printer 1 side, PAUSE state, error state, etc., the receiving process is not in time because it is operating etc. The data is output to the host computer 2 when the data cannot be received. In the Centronics interface 17, PA
The USE signal is output to the host computer 2 when the printer 1 side is in the PAUSE state such as the paper end state, the head-up state or the ribbon end state, and the FAULT signal is the host when the printer 1 side is in the error state. It is output to the computer 2.

In this embodiment having such a configuration, the printer 1 is connected to the RS232C interface 18 with respect to the host computer 2.
When an error condition occurs in the printer 1 or a PAUSE condition occurs when the printer 1 is connected via, the data reception is stopped as shown in FIG. BUSY signal is output as shown in b),
And FAULT at Centronics interface 17
Signal, RSF since PAUSE signal is generated from the output terminal 18 ₉ RS232C interface 18 as shown in the FIG. 4 (c)
The LT signal is also output. Then the host computer 2
Since the RSFLT signal is also received together with the BUSY signal, it can be determined that the cause of the data transmission failure is the printer 1 side. Thus, the operator can immediately inspect the printer 1 and perform work for releasing the BUSY state, such as setting of paper and ribbon, head-down and error checking.

When the data buffer becomes full in the printer 1, the reception of data is stopped as shown in FIG. 5 (a) and the BUSY signal is output as shown in FIG. 5 (b). As shown in FIG. 5 (c), the RSFLT signal is not output. Since the host computer 2 receives only the BUSY signal, the host computer 2 determines that the cause of the data transmission failure is the data buffer full, and waits until the printer 1 is ready to receive data.

Even when the host computer 2 is connected to the host computer 2 via the RS232C interface 18 which is a serial interface, the host computer 2 must cancel the BUSY state of the printer 1 due to the data unreceivable state of the printer 1. It is possible to determine for sure whether or not it will be released after a while.

When the printer 1 is connected to the host computer via the Centronics interface 17,
Since the PAUSE signal and the FAULT signal are output together with the BUSY signal, the host computer can surely determine the cause of the data unreceivable state of the printer 1 at this time.

[Effects of the Invention] As described in detail above, according to the present invention, even if the host computer is connected to the host computer using the serial interface, the cause of the BUSY state is released after waiting for a certain time, or the device side It is possible to provide a printer that can immediately determine whether or not some sort of release operation must be performed.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a block diagram, FIG. 2 is a concrete circuit diagram of an RS232C interface,
FIG. 3 is a specific circuit diagram of the Centronics interface, and FIGS. 4 and 5 are timing charts showing signal output timing when the printer is in the BUSY state by using the RS232C interface. 1 ... Printer, 2 ... Host computer, 11 ... CP
U, 17 ... Centronics interface, 18 ... RS2
32C interface, 17 ₆ …… Or gate circuit.

Claims (1)

[Claims] 1. A BUSY signal is sent to a host computer when the device becomes unable to receive data, and a PAUSE signal is sent when the status occurs at the paper end, head up, ribbon end, etc. of the device, and It has a parallel interface that has an output terminal that sends a FAULT signal when an error occurs in the device, and a serial interface that has only an output terminal that sends a BUSY signal when the device cannot receive data to the host computer. In a printer that connects one of the interfaces to a host computer and receives print data from the host computer and prints data, sends a logical sum signal of the PAUSE signal and FAULT signal of the parallel interface to the serial interface. A printer provided with an output terminal for switching.